emagtm

8/12/2019 emagtm

http://slidepdf.com/reader/full/emagtm 1/246

8/12/2019 emagtm


8/12/2019 emagtm


NISA/EMAG Training Manual Table of Contents

i

Table of Contents

Chapter 1 Introduction.................................................................................................... 1-1

Chapter 2 Installation Instructions ................................................................................. 2-1

Chapter 3 DISPLAY III – How it Works ....................................................................... 3-1

Chapter 4 DISPLAY III – Basic Options for Geometric Modeling ............................... 4-1

Chapter 5 DISPLAY III – Basic Options for Finite Element Modeling ........................ 5-1

Chapter 6 DISPLAY III – Miscellaneous Options ......................................................... 6-1

Chapter 7 Low Frequency Analysis ............................................................................... 7-1

Chapter 8 Modeling Session 1 ....................................................................................... 8-1

Chapter 9 Modeling Session 2 ....................................................................................... 9-1

Chapter 10 Modeling Session 3 ..................................................................................... 10-1







8/12/2019 emagtm


8/12/2019 emagtm


NISA/EMAG Training Manual Introduction

1-1

CHAPTER 1

INTRODUCTION

NISA/EMAG (Numerically Integrated elements for System Analysis, forELECTROMAGNETIC problems) is a general purpose finite element based computationalelectromagnetic code developed and maintained by EMRC to analyze electromagnetic field problems encountered in Electrical Engineering. NISA/EMAG is coupled with NISA/HEATfor analyzing coupled electrical and heat problems. Electromagnetic field analysis forarbitrary shaped domains with various possible boundary conditions require numerical toolssince the Maxwell’s equations and the equation of continuity must be satisfied along witharbitrarily specified boundary conditions. The material encountered can in general beanisotropic and non-linear. NISA/EMAG incorporates such tools into an integrated package.2D, axisymmetric and 3D arbitrary geometry can be simulated for all electromagnetic field problems. This program is comprised of two modules: Low frequency and High frequency.

The Low frequency module of NISA/EMAG handles electrical charges flowing or varyingat low frequency. For this the effect of Displacement current can be neglected. Itsapplications span a wide range of Electrical industries manufacturing Transformers,Electrical machines, Capacitors, Inductors, Resistors, Solenoids, Electrostatic devices,Biomedical equipments, High voltage equipments, Integrated circuit Technology, Electricalfurnaces and ovens, Electro-chemical cells etc.

The High frequency module of NISA/EMAG analyses high frequency devices ( Microwave,Millimeter and Optic frequency range) viz. Transmission lines, waveguides, waveguidediscontinuities, Integrated circuits, Couplers, Isolators, Circulators, Resonators, Antennasand scattering surfaces.

A brief overview of NISA/EMAG capabilities is given below.

Pre-processing

NISA/EMAG directly interfaces with the pre-processing module of the DISPLAY program;a 3D interactive color graphic program with extensive modeling capabilities for finiteelement model generation and problem definition. Highlights of the capabilities are:

• Both command and menu driven modes, with on-line help.

• 3-D geometric modeling including points, lines, arcs, curves, surfaces and solids as well

as surface intersections.

• Geometric transformations including translation, rotation, scaling, mirror imaging anddragging a curve along an arbitrary 3-D path.

• 3-D interactive finite element mesh generation including automatic node and elementgeneration.

• Mesh grading with uniform or non-uniform spacing.

8/12/2019 emagtm


Introduction NISA/EMAG Training Manual

1-2

• Merging separate models into larger one.

• Definition of element attributes including material and geometric properties.

• Specification of boundary conditions.

• Extensive model editing capabilities.

• Extensive plotting options including boundary line, hidden line removal and shrinkelement plots for selected elements or regions.

• Color shading and light effects.

• Model checking including calculation of element areas, volumes, normals and distortionindex.

•

Complete NISA/EMAG data deck generation.

Input data structure

• Simple modular input data structure and easy to use free format.

• Descriptive data group identification names reflecting the function of each data group.For example, electromagnetic material properties are entered in *MATEMAG datagroup.

• The data deck consists of three data blocks : The executive commands specifying theoverall control parameters in simple alphanumeric format, the model data block

describing the model characteristics and finally the analysis data block specifying thecurrent density, charge density, magnetic coercivity, boundary conditions and outputoptions.

• Data groups may appear in any order within each data block, with very few exceptions.

• Annotation echo of the input data.

• Extensive data checking and self-explanatory diagnostic messages.

Analysis Capability

Low frequency

The Low frequency module of NISA/EMAG is coupled with NISA/HEAT. Majorcapabilities of the Low frequency module of NISA/EMAG are categorized as follows:

• Main Analysis Types! Electric Field Analysis

8/12/2019 emagtm



1-3

! Magnetic Field Analysis

• Sub-Analysis Types! Electric Field Analysis

♦ Electrostatic Analysis♦ Steady State current flow

! Magnetic Field Analysis♦ Magnetostatic Analysis

# Using Magnetic vector potential# Using Magnetic scalar potential

♦ Magnetodynamic Analysis# For sinusoidal time variation using Magnetic vector potential# For arbitrary time variation using Magnetic vector potential

• Problem Dimensions! 2D!

Axisymmetric! 3D

• Types of Boundary Conditions! Dirichlet Boundary Conditions

# Electrostatic scalar Potential# Magnetic scalar and Vector Potential

! Neumann Boundary Conditions# Electric Flux Density# Magnetic Flux Density

! Source Boundary Condition# Electric Current Density# Electric Charge Density# Magnetic Coercivity# Current Density

• Non-linear Material specification! Magnetic material Properties

# B – H curve in Tabular form

• Property specification! Temperature Dependent Material Properties

♦ Permeability♦ Permittivity♦ Conductivity

# Tabular# Polynomial

! Orthotropic Properties

8/12/2019 emagtm



1-4

# Conductivity# Permeability# Permitivity

Major capabilities of the Heat module of NISA/HEAT are categorized as follows:

• Types of heat transfer analysis! Conduction Heat Transfer Analysis! Forced Convection Analysis! Natural Convection Analysis! Mixed Convection Analysis! Phase Change Analysis! Surface Radiation Analysis

• Types of Boundary Conditions! Dirichlet Boundary Conditions

# Temperature

! Neumann Boundary Conditions# Heat Flux

! Surface Convection Boundary Condition

! Radiative Boundary Condition

! Surface Radiation# Symmetry Plane# Outlets# Surfaces

! Time-dependent Boundary Condition# Temperature# Element Heat Generation# Surrounding/ambient temperature# Heat Flux

! Boundary Conditions in Local Coordinate Systems# Convection Heat Transfer Coefficient# Emissivity# Element heat generation# Heat Flux

! Nodal Heat Source and Element Generation

• Property specification! Temperature Dependent Material Properties

# Tabular# Polynomial

8/12/2019 emagtm



1-5

! Orthotropic Properties# Conductivity

High Frequency

Major capabilities of the High frequency module of NISA/EMAG are categorized as

follows:

• Type of analysis! Quasi-Static Analysis! Full Wave Analysis for Guided Waves! Full Wave Analysis for Resonant Cavities! Wave Scattering

• Problem Dimensions! 2D! Axisymmetric! 3D

• Type of boundary conditions# Electric Field Intensity# Magnetic Field Intensity# Absorbing Boundary conditions

Output Features

Various combinations of results at each node can be chosen to meet individual interest. Theformat of these results is consistent with the input format of DISPLAY III. The results

depend on the type of Analysis and Sub-Analysis chosen as given below:• Low Frequency

! Electric Field Analysis♦ Electrostatic Analysis

# Electric Field Intensity# Electric Flux Density# Electrostatic Scalar Potential

♦ Steady State current flow# Electric Field Intensity# Electric Current Density# Electrostatic Scalar Potential

• Magnetic Field Analysis♦ Magnetostatic Analysis

# Magnetic Field Intensity# Magnetic Flux Density# Magnetic Scalar or Vector Potential

♦ Magnetodynamic Analysis# Magnetic Field Intensity# Magnetic Flux Density# Magnetic Vector Potential

8/12/2019 emagtm



1-6

# Eddy Current Density# Total Current Density

• High Frequency! Quasi-Static Analysis

# Electric Field Intensity# Electric Flux Density

# Electric Scalar Potential! Full-Wave Analysis for Guided waves and Resonant Cavities

# Propagation constants for various Modes# Mode shapes for Electric Field Intensity# Mode shapes for Magnetic Field Intensity

! Scattering of Waves# Mode shapes for Electric Field Intensity# Mode shapes for Magnetic Field Intensity

Apart from the nodal results, some results are available in elemental form and some aslumped parameters. They are:• Low Frequency

! Electric Field Analysis♦ Electrostatic Analysis

# Stored Energy in each Element# Total Stored Energy# Capacitance

♦ Steady State current flow# Dissipated Energy in each Element# Total Dissipated Energy# Conductance

• Magnetic Field Analysis

♦ Magnetostatic Analysis# Stored Energy in each Element# Total Stored Energy# Inductance

♦ Magnetodynamic Analysis# Stored Energy in each Element# Total Stored Energy# Inductance# Dissipated Energy in each Element# Total Dissipated Energy# Conductance

• High Frequency

! Quasi-Static Analysis# Stored Energy in each Element# Total Stored Energy# Capacitance and Inductance Matrices

! Full Wave Analysis of Guided Waves# Wave Impedances# Scattering Parameters

! Full Wave Analysis for Resonant Cavities

8/12/2019 emagtm



1-7

# Wave Impedances# Scattering Parameters# Resonant Frequencies

Postprocessing

Graphical representation of results may be obtained interactively using post processingmodule of 3-D color Graphics DISPLAY program following a successful NISA run. A briefaccount of the postprocessing features are given below.

• Various geometry plotting options including hidden line removal, boundary and featureline plots and view manipulation including rotation, scaling and zooming.

• EMAG vector plots for Electric and Magnetic fields and current density components.

• Contour plots for Electrostatic and Magnetostatic Potentials, Electric and Magnetic FieldIntensities, Electric and Magnetic Flux densities, Different Current Densities andtemperature.

• Contour plots for cut sections of 3-D models.

• XY profiles plots for various output quantities.

• Time history plots for various output quantities.

8/12/2019 emagtm



1-8

This page intentionally left blank

8/12/2019 emagtm


NISA/ EMAG Training Manual Installation Instructions

2-1

CHAPTER 2

INSTALLATION INSTRUCTIONS

This is version 7.0 installation guide for NISA family of programs on PC, i.e., on DOS,Windows 95 and Windows NT operating systems using CD-ROM.

SYSTEM REQUIREMENTS

• DOS or Microsoft Windows NT or Microsoft Windows 95.• PC with 80386 (or higher) microprocessor, math co-processor and CD-ROM drive.• Minimum 8 MB RAM.• Minimum 90 MB hard disk for DOS installation (for All Modules).• Minimum 120 MB hard disk for Windows installation (for All Modules).

For Windows NT/95: VGA or higher resolution video adapter. A 256-color video adapter (orhigher) is required for DISPLAY III. Super VGA resolution is recommended.

PREPARATION

Earlier versions of EMRC NISA/DISPLAY must either be deleted or saved under a differentname.

Windows NT:

• The PC should be booted in the high resolution mode and not in the VGA mode.

Windows NT/95:

• The Color Palette in Display Settings (under Control Panel) must be set to 256 colors.• The option "show only true type fonts in Applications" in the "True Type" setting under

"Fonts->Option" (under Control Panel) must be UNCHECKED.

Insert the EMRC CD in the CD-ROM drive.

If installing the Production Version:• Connect the EMRC Security Plug to the parallel port of your computer.• Insert the 3.5" Master Installation Disk (containing the file EMRCPCV7.SEC) in the floppy

drive.

Note: If the Computer (e.g. Laptop) does not have a simultaneous access to BOTH the 3.5"floppy drive and the CD-ROM drive, do the following:

1. Copy the file EMRCPCV7.SEC from the Mater Installation Disk to the hard drive (atthe root level, C:\).2. During the installation from the CD-ROM, use DRIVE C for the "Security FileDrive".

8/12/2019 emagtm


Installation Instructions NISA/ EMAG Training Manual

2-2

INSTALLING DOS VERSION

At the DOS Prompt, run "<CD-ROM drive letter>:\DOS\INSTALL" and follow theinstructions on the screen.

Verifying the DOS Installation:

The file EMRCDRIV.DAT should be created at the root level (under C:\). The following two (2)directories should be present under your hard drive:

EMRCNISA

EMRCVERF

The EMRCNISA directory should contain the file EMRCPCV7.SEC. (This file can be found inthe Master Installation Disk.)

At the DOS Prompt, execute SET and check the following:

Path=...;<hard drive letter>:\EMRCNISA;... NISA=<hard drive letter>:\EMRCNISA NISALOCL=<hard drive letter>:\EMRCNISA

Notes: The DOS version can be executed only when the PC is booted directly to DOS.

The use of SMARTDRV.EXE is recommended. The following options with SMARTDRVshould be entered in your AUTOEXEC.BAT file:

C:\DOS\SMARTDRV.EXE C+ D+ E+ F+ /CC:\DOS\SMARTDRV.EXE C+ D+ E+ F+ /R

where C, D, E, and F designate the hard drive letters. The appropriate hard drive letters of your

computer must be used.

A DOS Mouse Driver must be installed to run NDSHELL when the PC is booted directly toDOS.

The NISA modules will NOT run if EMM386.EXE is used as the system memory manager. Theuse of HIMEM.SYS is recommended. The memory manager is defined in the CONFIG.SYSfile.

The DOS installation procedure is now complete. Please REBOOT your computer and refer tothe "NISA/DISPLAY Operations Guide" for full details on the DOS version of NISA/DISPLAY

Programs.

INSTALLING WINDOWS 95 VERSION

Click on Start, point to Run, enter "<CD-ROM drive letter>:\I386\SETUP" (For NEC PC, enter"<CD-ROM drive letter>:\I386\SETUPNEC"), click the OK button and follow the instructionson the screen.

8/12/2019 emagtm



2-3

After the installation of the NISA Family of Programs, if requested, SETUP will launch theinstallation of Exceed. Exceed is an X-Windows simulator that is used by DISPLAY III for itsX-Window applications.

During the installation of Exceed:

• Select the default options (Personal setup type and Express method).• !! Important !! Define the Exceed home directory as "<hard drive letter>:\EXCEED.95"

instead of the default directory "C:\Program Files\exceed.95".• Select Yes to tune Exceed. Tuning Exceed may take some time.• Error messages may be issued regarding not being able to install some Windows System

files. If the error occurs and Exceed DID NOT get tuned:

- Select Yes to restart Windows.- Click on Xconfig from the Exceed Folder.

- Click on Performance then Tune.- Select RUN ALL.- Resuming the installation procedure.

Configuring Exceed:

• Click on Xconfig from the Exceed Folder.• Click on Performance.• Set "Maximum Backing Store" to Always, "Default Backing Store" to When Mapped, and

"Minimum Backing Store" to When Mapped.• Uncheck "Draft Mode" and Click on Tune.

• Set "Graphics Operation" to FillPolygonSolid, "Window Method" to Method 1, and "PixmapMethod" to Method 1. Choose Ok.

• Choose the Ok button and select Yes.

Setting NISA and Exceed environments:

• Edit AUTOEXEC.BAT and insert:PATH=<hard drive letter>:\EXCEED.95;%PATH%

For NEC PC Only!:

• Edit AUTOEXEC.BAT and insert:SET PCDRIVE=A:\

The Windows 95 installation procedure is now complete. Please REBOOT Windows 95 beforeusing the NISA Family of Programs.

8/12/2019 emagtm



2-4

Verifying the Windows 95 Installation:

• The following files should be created at the root level (under C:\ for PC and A:\ for NECPC).

EMRCDRIV.DAT

EMRCWIND.DAT

Note: If these files are not found, they can be easily created. These files must contain a onecharacter line identifying the <hard drive letter>.

• The following directories should be present under your hard drive:EMRCNISA.NTEXCEED.95EMRCVERFEMRCRUN

• The EMRCNISA.NT directory should contain the file EMRCPCV7.SEC.

(This file can be found in the Master Installation Disk.)

At the DOS Prompt, execute SET and check the following:Path=..;<hard drive letter>:\EXCEED.95;..

Note: !! IMPORTANT !! If you get the error "A required .DLL file, XLIB.DLL, was not Found"when starting DISPLAY III, this means that Exceed was not installed under <hard driveletter>:\EXCEED.95. Please refer to the section "Path to Exceed" under Trouble Shooting toresolve the problem.

• For NEC PC, At the DOS Prompt, execute SET and check the following:

PCDRIVE=A:\

INSTALLING WINDOWS NT VERSION

For Windows NT 3.51:

In The Windows Program Manager, choose Run from the File menu.

For Windows NT 4.0:

Click on Start and choose Run.

In the Command line box, type "<CD-ROM drive letter>:\I386\SETUP" (For NEC PC, enter"<CD-ROM drive letter>:\I386\SETUPNEC"), choose the OK button and follow the instructionson the screen.

8/12/2019 emagtm



2-5

After the installation of the NISA Family of Programs, if requested, SETUP will launch theinstallation of Exceed. Exceed is an X-Windows simulator that is used by DISPLAY III for itsX-Window applications.

During the installation of Exceed:

• Select the default options (Personal setup type and Express method).• !! Important !! Define the Exceed home directory as "<hard drive letter>:\EXCEED.NT"

instead of the default directory "C:\Program Files\exceed.nt" (for Windows NT 4.0) or"C:\win32app\exceed" (for Windows NT 3.51).

• Select Yes to tune Exceed. Tuning Exceed may take some time.

Note: Some error messages regarding Start Service (when no network is available) might beissued. These messages should be ignored.

Configuring Exceed:

• Click on Xconfig from the Exceed Folder.• Click on Performance.• Set "Maximum Backing Store" to Always, "Default Backing Store" to When Mapped, and

"Minimum Backing Store" to When Mapped.• Choose the Ok button and select Yes.

Setting NISA and Exceed environments:

• From the Control Panel, Click on System. (For Windows NT 4.0) select the Environment tab.

• In the Variable line box, type "Path".• In the Value line box, type "<hard drive letter>:\EXCEED.NT", and select Set.

For NEC PC only!:

• In the Variable line box, type "PCDRIVE".• In the Value line box, type "A:\" and select Set.

Updating DESKTOP (Windows NT 3.51 only!):

• Click on Desktop from Control Panel.• Under Applications, "Fast "Alt+Tab" Switching" should be CHECKED and "Full Drag"

Should be UNCHECKED.• Choose the OK button.

8/12/2019 emagtm



2-6

Installing Sentinel Security Drives:(can be executed only at the System Administrator level)

For Windows NT 3.51:

• In The Windows Program Manager, choose Run from the File menu.

For Windows NT 4.0:

• Click on Start and choose Run.• In Command line box, type "<CD-ROM drive letter>:\NT_PLUG\INSTALL", and choose

the Ok button.• Click on Functions, select "Install Sentinel Drives", and choose the Ok button.

The Windows NT installation procedure is now complete. Please REBOOTWindows NT before using the NISA Family of Programs.

Verifying the Windows NT Installation:

• The following files should be created at the root level (under C:\ for PC and A:\ for NECPC).

EMRCDRIV.DATEMRCWIND.DAT

Note: If these files are not found, they can be easily created. These files must contain a onecharacter line identifying the <hard drive letter>.

• The following directories should be present under your hard drive:EMRCNISA.NTEXCEED.NTEMRCVERFEMRCRUN

• The EMRCNISA.NT directory should contain the file EMRCPCV7.SEC. (This file can befound in the Master Installation Disk.)

• At the DOS Prompt, execute SET and check the following:Path=..;<hard drive letter>:\EXCEED.NT;..

Note: !! IMPORTANT !! If you get the error "A required .DLL file, XLIB.DLL, was not Found"

when starting DISPLAY III, this means that Exceed was not installed under <hard driveletter>:\EXCEED.NT. Please refer to the section "Path to Exceed" under Trouble Shooting toresolve the problem.

• For NEC PC, At the DOS Prompt, execute SET and check the following:PCDRIVE=A:\

8/12/2019 emagtm



2-7

• The Sentinel Security Driver must be properly installed and activated. To verify:* Double click on the Devices Icon from the Control Panel.* Scroll down and search for Sentinel under the Device Column* The Status column should indicate "Started" and the Startup column

should indicate "Automatic".

IMPORTANT NOTES

ON-LINE HELP FOR WINDOWS NT/95 VERSION:

An on-line HELP is installed under the EMRC Help icon for the Windows NT/95 versions. Thisincludes information about using the GUI Windows Interface, using NISA/DISPLAY modulesand other utilities, such as printing.

EXTRACTING HARD COPY IMAGES FROM DISPLAY III:

Either the whole or a partial DISPLAY III window can be sent directly to an attached printer orto a bitmap file (directly to a BMP file or to Windows Clipboard) through the Edit menu of the Xicon (for Windows 95 or Windows NT 4.0) or button (for Windows NT 3.51) located at theupper left corner of your DISPLAY III window. For further details, please refer to the topic"printing" in the on-line HELP.

The Exceed tool bar can be closed by clicking the upper left corner button, or moved elsewhere by dragging it through the top bar. It can also be customized (through the toolbar customizeicon) to include all the edit menu options (printing, copying to a file, etc.).

In order to obtain an image from DISPLAY III with a white background, the REVERSE

SCREEN option must be selected in DISPLAY III before extracting the bitmap image.

RUNNING ANALYSIS MODULES FROM WITHIN DISPLAY III:

The Windows NT/95 version of DISPLAY III can now execute many NISA modules directlyfrom within DISPLAY III through the menu syntax:

NISA DATA GROUP --> EXECUTION SETUP --> EXECUTE NISA.

The default path for NISA II is <hard drive letter>:\EMRCNISA.NT\16MEG. In order to changethis path, you need to edit the file EMRCWIND.DAT and insert the line

<hard drive letter>:\EMRCNISA.NT\XXMEGwhere XX is the new MEG version.

For instance, if you installed an 8MEG version of the software in drive D, the contents ofEMRCWIND.DAT should be as follows:

DD:\EMRCNISA.NT\8MEG

8/12/2019 emagtm



2-8

BATCH OPERATION:

Under each verification directory (e.g., EMRCVERF\STATIC), a batch file is created [e.g.,

EMAG.BAT (for DOS) or WEMAG.BAT (for NT/95)]. Executing such a file from the MS-DOS prompt will run all the verification problems in the directory and create a log file(NISARUN.LOG). You can refer to this file to create your own batch files to run your NISAapplications.

Note: The directories "<hard drive letter>:\EMRCNISA.NT\ALLMEG" and"<hard drive letter>:\EMRCNISA.NT\XXMEG" (where XX is the MEGversion) need to be added to the path before running the batchfiles under Windows NT/95.

GENERAL GUIDELINES FOR EXECUTING NISA/DISPLAY

The NISA modules can be executed either by double clicking on the module icon or from theMS-DOS Prompt Command box. Executing the NISA modules at the MS-DOS Prompt allowsthe user to run the NISA applications in a BATCH mode.

For instance, if the 16 MEG version of the NISA Modules is installed in drive D, the commandto execute EMAG at the MS-DOS Prompt is as follows:

D:\EMRCNISA.NT\16MEG\EMAGS input_file output_file nopause where, input_file andoutput_file are the names of the input and output files respectively.

One can also add the directory D:\EMRCNISA.NT\16MEG to the PATH (in the fileAUTOEXEC.BAT). The command to execute EMAG is then simply:EMAGS input_file output_file nopause

One can also create a batch file (.BAT) that will execute the NISA Modules multiple times withdifferent input files. A batch file that will execute EMAG (for example, named SAMPLE.BAT)with two different input files will contain the following lines:

D:\EMRCNISA.NT\16MEG\EMAGS input_file1 output_file2 nopause | RK_NTLOGD:\EMRCNISA.NT\16MEG\EMAGS input_file2 output_file2 nopause | RK_NTLOG

RK_NTLOG is a program that will save the information output on the screen to a log file named NISARUN.LOG. RK_NTLOG.EXE is installed at the root level (C:\) and underEMRCNISA.NT.

The Batch file SAMPLE.BAT can be executed at the MS-DOS Prompt by typing: SAMPLE

8/12/2019 emagtm



2-9

EVALUATION VERSION

The Evaluation Version of the NISA Family of Programs is limited to 600 Degrees of Freedom.It does not require a software license and has been designed to execute without the presence of asecurity plug in the parallel port. A special security file, EMRCPCV7.SEC, is available in the

EMRC CD-ROM to allow users to execute an Evaluation Version of any software module,licensed or not, in the NISA Family of Programs.

Note: The original security file must be restored to the EMRCNISA.NT directory in order toexecute the Production Version of the licensed software modules.

For users who are familiar with DISPLAY III can skip Chapter 3 to 6.

8/12/2019 emagtm



2-10


8/12/2019 emagtm


NISA/ EMAG Training Manual DISPLAY III – How it Works

3-1

CHAPTER 3

DISPLAY III — How it Works

The DISPLAY III pre-processor is a state-of-the-art three-dimensional interactive graphics program for easy modeling in color. The look and feel of the program is CAD like, but its primary goal is to provide an easy user interface for creating the input files for the finite elementsolver. The first step in the modeling process is to create a geometric representation of thecomponent or system. After successful completion of this step, finite elements are generated andloads and boundary conditions are imposed to obtain the finite element model. This FEA modelis then used to create input files for different solvers offered within NISA.

The modeling process can be divided into two broad steps:

1. Geometric Modeling:

The purpose of the geometric modeling phase is to represent given geometry in terms of points(grids), lines, surfaces (patches) and volumes (hyperpatches). Suppose, a two-dimensional non-fringing parallel plate capacitor is to be modeled. An approach to this modeling will be togenerate four corner points (grids) by defining their coordinates or by snapping the cursor on thescreen. Now, join the grids to create four lines. At this stage, join two opposite lines to create asurface (patch). This surface is the geometric representation of the non-fringing parallel platecapacitor. However, if the third dimension is of significance, one may decide to model it as asolid structure. In that case, the existing patch is translated in the third dimension by the amountof thickness. By joining opposite patches in the direction of thickness, a volume geometry(hyperpatch model) is obtained. This representation of the geometry in terms of grids, lines, patches and hyperpatches is referred to in this tutorial as the geometric model.

2. Finite Element Modeling:

The finite element modeling is described as the representation of the geometric model in terms offinite number of elements and nodes, which are the building blocks of the numericalrepresentation of the model for solution. In addition to information about element and nodes,this model also contains information about material and other properties, electromagnetic sourcesand boundary conditions. This phase of modeling is easily performed if the user follows thefollowing steps:

a) Finite Element Generation: The user maps the geometric entities created in the previous stepwith finite elements and nodes at this step. The complete geometry is now defined as anassemblage of discrete pieces called elements, and are connected together at a finite numberof points called nodes. The mapping is achieved by automatic and semi-automatic optionsavailable in DISPLAY III. If complete automatic means are used (automatic mesh

8/12/2019 emagtm


DISPLAY III – How it Works NISA/ EMAG Training Manual

3-2

generation) to create the mesh, the user can skip the next step of the model verification and proceed with the other steps.

b) Model Verification: At this stage, verify the model to ensure that the model is physically andnumerically correct. It makes sure that all the elements generated earlier are acceptable to

Finite Element Solver. Any warped, skewed or distorted elements would be highlighted inthis procedure. The user should pay special attention to verification of the model to checkfor discontinuities by using the boundary plot. The user should also check for aspect ratios,included angle, warping index by using the distortion index check, and the elementconnectivity check for proper orientation. Use different viewing orientations, remove hiddenlines and shrink elements to confirm that the model is correct.

c) Problem Definition: Element and material properties, along with electromagnetic sources and boundary conditions, are defined for the model during this stage.

d) Editing and File Management: This is the last stage of modeling and is useful in order to

customize the NISA input file to be generated as per the needs of the particular analysis andsub-analysis type. The user can specify all material properties again, time varying sources,time integration schemes, time history schemes to be selected in output and print controls.

The above are the guidelines for easy modeling with DISPLAY III. The actual strategy formodeling a realistic practical problem is essentially an art, and there are no rigid rules to follow.However, some general guidelines can be evolved for modeling and these are given in chapters10 and 11. The same problem can be modeled by a variety of approaches. DISPLAY III pre- processor offers unparalleled flexibility by offering numerous options for construction ofgeometry and finite elements. The user is strongly encouraged to obtain a copy of the DISPLAYIII user manual to find detailed information on the capabilities and options available inDISPLAY III.

DISPLAY III MENU STRUCTURE

DISPLAY III can be used in the command mode (commands typed at the keyboard) as well as inthe menu mode (using the mouse). Some experienced users prefer to use the command mode forspeedy modeling. The command mode, however, requires knowledge of the DISPLAYcommand structure.

Most users prefer the menu mode where the user interfaces with the program using the mouse.

Working with the menu system does not require any knowledge of the DISPLAY commandsyntax.

The menu structure in DISPLAY III is built with the concept of global menus and subsequentlower level submenus. The ‘tree’ structure of the menu system changes dynamically and offersthe next logical choice of menus. One can thus move around until a desired operation is performed and then go back to a higher level of menus or directly go to another global menu to perform another set of instructions. DISPLAY III is also equipped with ‘HOT’ buttons, which

8/12/2019 emagtm



3-3

can be executed from any level of the menu for operations, which occur most frequently. The program also provides a friendly ‘numeric keypad’ or graphical keyboard area, which may beused with the cursor to enter numerical data without using the keyboard.

SWITCHING BETWEEN MENU AND COMMAND MODES

Once you get more acquainted with the program, you may want to use both menu mode for easeand command mode for speed. You will use the basic commands to make the modeling fasterand use the menu options when you are at a loss. DISPLAY III allows simple ways to move.Any time you want to switch to command mode, simply click the hot button ‘COM’ or just typein ‘C’ from the keyboard. Make sure, however, that you are not in the middle of an operation.

If you want to return to menu mode, simply type in ‘MENU’ from the keyboard.

USING THE MOUSE

The three button mouse is the most common device for communicating with the program. Theleft button is the positive or accept button whereas the right button is the negative or reject button. When selecting options from the menu, the left button is used. The right button istreated as reject (or escape) and is used to move back to a higher level in the menu tree. Thisdefault can be changed by options available under the global menu SET/SHOW. On systemswith one mouse button, the button is used as the positive or accept button and the negative orreject response is given through the keyboard.

To select an entity (suppose, a grid) the cursor is moved by the mouse near the grid and the left

button is pressed. If the cursor is not near enough to the grid and there are various other gridsnear by, the program will highlight the nearest grid and ask ‘Do you want to pick this entity(Y/N)’. The user can accept by typing ‘Y’ on the keyboard or by clicking the left button. Toreject type ‘N’ or click the right button.

8/12/2019 emagtm



3-4

THE SCREEN AND THE MENUS

The DISPLAY screen is divided into the following regions or boxes.

1. Plot Area: Center of the screen where the model is displayed.

2. Dialogue Area: Displays messages and instructions prompted by the program. The user mayor may not need to insert some data at this region. This region is also used for keyboardentries in the command mode of operation.

3. Top Bar Menu: The top level of the menu tree. This region is always active and displayed.Any one of the eight global options at this top level can be accessed at any time by clickingthe mouse on the selected option. The top bar menu offers the following selections:

GEOM: For creating all geometric entities such as grids, lines, surface patches, volumehyperpatches.

FEM: For creating finite elements, nodes, boundary conditions, loads, material and realconstant properties.

DYMES: This selection is for options related to the DYMES program.

VIEW: For view manipulation such as rotations, windowing and zooming, etc.

Fig. 3.1

8/12/2019 emagtm



3-5

POST: Provides result interpretation and post-processing options for different analysis.

MISC: Provides miscellaneous options such as layers, sets, device colors, etc.

SET/S: To set or show default parameters that control DISPLAY operation.

FILES: Provides access to all file manipulation options such as read and write of varioustypes of files, ending or restarting in a session.

4. Current Option Menu: This region offers the different options available for furtherexecutions at any stage of the menu operations. At any time, this area reflects the logicalchoices available as next available options depending on the previously performedoperations. At the beginning of a session, the choices in this region coincide with the optionsavailable from the top bar menu. Thereafter, this area displays the dynamically changingoptions available to the user.

GEOM FEM NISA DYMES VIEW POST MISC SET/S FILES

GLOBAL OPTIONS

GEOMETRY OPTIONS

GRIDLINEPATCHHYPERPATCHPLANE PRIMITIVELCS SYSTEM

WORK PLANE NURB CURVESDATA ENTITY

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAYOCT/01/97 3:03:01

ROTX

ROTY

ROTZ K E Y B O A R D /

T R I A D A R E A

H O T O P T I O N S

M E N U

O P E

R A T I O N

M E N

U

S U B - L E V E L

M E N U

8/12/2019 emagtm



3-6

Suppose we select the GEOM option from the top bar menu as a starting point in creating a patch (surface). Once the top menu GEOM is selected, the current option menuautomatically changes to options available within this GEOM selection. This is shown in

Fig. 3.2.

Now, to create a patch we select the PATCH option from this menu. The programautomatically brings different options available for creation of a patch as a submenu in thisregion. All the selections under this submenu are relevant to creation/modification/copyingor miscellaneous options related to a patch. This is shown in Fig. 3.3.


GLOBAL OPTIONS

GEOMETRY OPTIONS

GRIDLINEPATCHHYPERPATCHPLANE PRIMITIVELCS SYSTEMWORK PLANE NURB CURVESDATA ENTITY

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0

K E Y B O A R D

/

T R I A D A R E A

H O T O P T I O N S

M E N U

O P E R A T I O N

M E N U

S U B - L

E V E L

M E N U

GLOBAL OPTIONS

GEOMETRY OPTIONS

PATCH OPTIONS

CREATECREATE ON GEOMCREATE ON PRIMMODIFYMOVECOPYMISC OPTIONS

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX

0ROTY0

ROTZ0 K

E Y B O A R

D /

T R I A D A R E A

H O T O P T I O N S

M E N U

O P E R A T I O N

M E N U

S U B

- L E V E L

M E N

U

Fig. 3.3

8/12/2019 emagtm



3-7

Once you select CREATE option from the above menu, the program will change theavailable options to those related specifically to the creation of a new patch. There are

various ways to create a new patch and the available options are displayed in Fig. 3.4.

You may choose the WORKPLANE option to create a new patch and the program offers yetanother submenu to ask you related information about the workplane on which you want tocreate a patch by using the cursor. The new options on this region will look as shown in Fig.3.5.

GLOBAL OPTIONS

GEOMETRY OPTIONSPATCH OPTIONS

CREATECREATE ON GEOMCREATE ON PRIMMODIFY

MOVECOPYMISC OPTIONS

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0 K

E Y B O A R D /

T R I A D A R E A

H O T O P T I O N S

M E N U

O P E R A T

I O N

M E N U

S U B - L E V E L

M E N U

GLOBAL OPTIONS

GEOMETRY OPTIONS

GRIDLINEPATCHHYPERPATCH

PLANE PRIMITIVELCS SYSTEMWORK PLANE NURB CURVESDATA ENTITY

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0 K

E Y B O A R D /

T R I A D A R E A

H O T O P T I O N S

M E N U

O P E R A T

I O N

M E N U

S U B - L E V E L

M E N U

GLOBAL OPTIONS

GEOMETRY OPTIONSPATCH OPTIONSCREATE PATCHES

GRIDMETHOD NODE METHODLINE METHODARC

CONSTRACTIONWORKPLANE

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0 K

E Y B O A R D /

T R I A D A R E A

H O T O P T I O N S

M E N U

O P E R A T

I O N

M E N U

S U B - L E V E L

M E N U


Fig. 3.4

8/12/2019 emagtm



3-8

5. Sublevel Menu: This region reflects the menu level where the user is in at any time andhelps the user keep track of previous menu operations. The user can click the mouse at anygiven level here to backtrack and choose different sets of options to branch out in the menutree.

Operation Menu: This menu contains ‘tokens’ relating to any particular option picked bythe user. These tokens are displayed in the same area as in the ‘Current Options Menu’. The‘tokens’ are input that are needed to perform a certain operation. Suppose it is required to

GLOBAL OPTIONS

GEOMETRY OPTIONSPATCH OPTIONS

CREATECREATE ON GEOMCREATE ON PRIMMODIFYMOVECOPYMISC OPTIONS

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0

GLOBAL OPTIONS

GEOMETRY OPTIONS

GRIDLINEPATCHHYPERPATCHPLANE PRIMITIVELCS SYSTEMWORK PLANE NURB CURVESDATA ENTITY

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0


GLOBAL OPTIONS

GEOMETRY OPTIONSPATCH OPTIONSCREATE PATCHES

GRIDMETHOD NODE METHODLINE METHODARCCONSTRACTIONWORKPLANE

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0

GLOBAL OPTIONSGEOMETRY OPTIONSPATCH OPTIONSCREATE PATCHESPATCH WPL

WORKPLANE IDSNAP MODE NO-OF-POINTSUVW-KEYINUVW-LCS-TYPECURSOR ON WPLPATCH OUT IDEXECUTE (GO)

PLO ERA SRH DEL

SVW ORN COL LAB

HLP EXE UND RES

REG CLR WIN PAN

HOT REG UNW COM

KBD ABT

EMRC NISA DISPLAY

OCT/01/97 3:03:01

ROTX0

ROTY0

ROTZ0

Fig. 3.5

8/12/2019 emagtm



3-9

translate an existing line to create another new line. It is necessary that the followinginformation is supplied to the program:

a. ID of the line to be translated.

b. ID of the new line to be created.

c. Distance by which the existing line is to be translated in each global direction (DX, DY, DZ).

The above information needed to perform the translation operation are ‘tokens’ for thetranslation option. Suppose you select the ‘Translate’ option in the ‘Current Level Menu’, the program then automatically displays the related tokens as a part of the ‘Operation Menu’.

Tokens are color coded and are used for the following purposes:

White Tokens: For these tokens, default values are used unless you override them with

values.

Red Tokens: These tokens require user specified data for execution and no default valuesare assumed.

Green Tokens: These tokens result in execution with user specified input and/or systemdefaults.

Most operation menus have EXECUTE (GO) as the last token. After all other tokens have beenspecified or the default values accepted, you should click this token for execution.

Triad Area: This region on the right hand lower portion of the screen which displays the globalaxes orientation for the model.

Auxiliary Keyboard Area: If the hot button KBD is clicked by the mouse, a numeric keypadappears on top of the triad area as shown in Figure 3.6. This is an auxiliary keyboard, which can be used to insert some numerical values simply by clicking the mouse on different numericvalues. Clicking the KBD hot button at the end of using the keyboard or execution of thecommand will return it to displaying the global triad axis.

7 8 9 , F1 F2 F34 5 6 / F4 F5 F6

1 2 3 – Delete

0 . E + Enter

Fig. 3.6

8/12/2019 emagtm



3-10

Label Boxes: Just above the triad area there are three boxes, which are used for labeling purposes. The topmost box is used to declare the NISA version, the middle box shows the timeand date of your session, and the lowermost box indicates, with a blink, if the program isexecuting a command or not. The yellow dot on the red bar blinks when the program isexecuting a command and remains steady when the program is waiting for further instructions

from the user.

6. Hot Options Menu: This region contains a few “hot” buttons, which can be executed at anytime of the modeling process. These buttons generally provide access to major auxiliarycommands such as aborting execution of a previous command, viewing the model from adifferent angle or simply replotting the whole or part of the model. The options provided inthese hot buttons are executed instantly and the control is returned to the original menu levelwhere the user was before clicking in the hot button. Sometimes a new list of options mayappear in the current level menu as a result of executing a hot button, but it is merely anavailable option for the hot button operation itself. The original current menu level will become active as soon as the hot button operation is performed.

The hot buttons are in two colors — yellow and white. White buttons are “super-hot” in thesense that they can be executed at all times when DISPLAY is waiting for input of any nature,even in the middle of some other operation. Yellow buttons cannot be picked when the programis expecting some other input during execution of another option. Yellow buttons, are alsodifferent in the sense that they usually bring up a list of options to choose from.

The following “hot” buttons are as will look as shown in Figure 3.7 and are described brieflyfollowing the figure.

PLO ERA SRH DELSVW ORN COL LAB

HLP EXE UND RES

RGN CLR WIN PAN

HOT REG UNW COM

↑ ↓ KBD ABT

PLO: Used to plot entities. It opens up another menu and allows you to specify which entities

are to be plotted.

SVW: Allows you to change current viewing angles from a set of standard views such as planview, front/back view, isometric view and other predefined views.

HLP: Offers access to the DISPLAY system help options. The user can select from differenttopics simply by clicking the cursor from selection of help.

Fig. 3.7 Hot button area

8/12/2019 emagtm



3-11

RGN: To regenerate a view on the screen, which is partially rubbed out because ofinsertion/deletion of entities on an existing view.

HOT: Clicking on this button brings up another set of “hot” buttons on the palette as shown inFigure 3.8. As the available options grow in the program, the blank spaces in the palette will be

used to provide more hot buttons in the future.

ERA: To erase entities from the database by selecting another set of options. This enables theuser to temporarily remove unnecessary entities from the active set without actually deletingthem from the database.

ORN: Allows you to change current viewing angles by snapping the cursor on positions from

Fig. 3.8

Fig. 3.9

8/12/2019 emagtm



3-12

the horizontal/vertical/ring bar area. This dynamic viewing option is extremely useful whentrying to view a complicated model from different angles. The change of angles and viewing isinstantaneous. The representation of viewing angles are shown in Figure 3.9.

EXE: Allows execution of user or system defined commands.

CLR: Allows the user to clear the screen and remove everything from the active set. Note thatentities, however, remain in the database.

REG: Allows the user to create a new region on the screen where the plotting should be done.

↑: Allows you to scroll up the dialogue area and see what commands/responses weregiven/obtained from the program in previous operations.

↓ : To scroll the dialogue area down.

SRH: To search and highlight entities of the model.

COL: To change colors of existing entities in the model.

UND: To undo the most recent command that has been executed and is useful whereaccidentally catastrophic instructions were given in the previous command.

WIN: Allows you to create a window by zooming in to a part of the model where magnifiedviews are needed for inspection.

UNW: Allows you to get out of a window and recreate the model as an original, after you have

used the WIN or PAN options.

KBD: This is a toggle, which acts as a switch between the numeric keypad and the global triadaxes display area. More description of this keyboard is available during description of thisnumeric keypad in the later part of this section.

DEL: To delete selected entities from the model. This option opens a menu where selections areto be made for entities, which are to be deleted from the database.

LAB: Is used to set the ID labels of entities as plot ON/plot OFF. If set ON, the correspondingentities will be plotted with their ID numbers on the screen.

RES: Allows you to reset the complete graphics area including the menu areas.

PAN: Allows you to slide a window any direction to enable you to view parts of the model,which are otherwise not visible.

COM: Allows you to switch back to command mode of operations should you prefer to key inthe commands instead of using the menu mode.

8/12/2019 emagtm



3-13

ABT: Allows you to abort the current display option. If you have made a mistake, which is being executed and is taking too long a time, this is a good way to get out of that.

REV: Allows reversing the parametric directions of different entities.

DIR: Used to plot parametric directions of different entities.

QRY: On-line query system used in post-processing. Allows the user to point at entities andobtain the corresponding numeric values.

RCR: To set the recording mode on/off.

EDG: Enables you to plot the edges of the geometric and elemental entities, which are selected,from the menu.

B.C.: This hot option will bring a hot BC-management menu on the fly, which is used tomanage boundary condition data. From a BC-entity set menu, selected boundary condition datacan be erased, plotted, deleted, searched, etc. on the fly. Also a BC-status form gives a complete picture of current boundary conditions.

FAC: Enables you to plot the faces of geometric or elemental entities.

EVA: Brings up the evaluator (scientific calculator) for evaluation of expressions.

Distance between two screen points

To specify whether inside or outside of the box/border to be selected

Set the values of the contours for the contour plots

Ζοοm: To zoom a portion of the screen

To create lines from the grid points selected by the pointing device

For extracting grid points

COM: To toggle between menu mode and command mode

KBD: For activating graphical key board pad

ABT: To abort the current operation

HOT: For toggling between the two hot menus

8/12/2019 emagtm



3-14

‘FORMS’ IN DISPLAY III

In finite element modeling, a good portion of data do not have any graphical meaning and aretherefore, not represented graphically. Element material properties are such an example. Themodel cannot graphically interpret (except showing different colors) the material property values

supplied by the user. In these cases, you will find the need to use ‘FORMS’. Forms enable youto input information without having to remember the command structure and with as little usageof the keyboard as possible. A typical form is shown in Figure 3.10.

You may enter the required data corresponding to boxes and then save/reset and quit from theform. Note that the forms may be very long and you may need to use the horizontal or verticalscroll bars to look for additional data.

MODELING IN COMMAND MODE

In the command mode, you type in valid DISPLAY III commands in the dialogue area of thescreen and interact with the program. You may type in one command at a time or you may alsotype in multiple commands on the same line and execute them at one time.

Fig. 3.10 Material Property Form

8/12/2019 emagtm



3-15

The most general form of DISPLAY III command structure is shown below:

Entry No. 1 2 3 4 5

NAME FUNCTIONS INPUT-ID-LIST OUTPUT-ID-LIST DATA

entry variable/(token) description

1 NAME A valid keyword — usually indicates the type of entity being created, edited or manipulated.

2 FUNCTION Usually indicates the option or function being performedsuch as ADD, DEL, etc.

3 INPUT-ID-LIST The list of existing entities on which the function is being

performed.

4 OUTPUT-ID-LIST The list of IDs for new entities that are being generated.

5 DATA The data used by the command to perform the function.

As an example, let us consider the command:

LIN, TRS, 1, 2, 10

The first entry LIN, is the entity on which the function TRS (Translate) will be performed tomove existing line 1 (input line-ID) by a distance of 10 units in the global X direction (data) tocreate a new line ID 2 (output line ID).

Note that the above is the general form for commands. Most of the commands for creation,manipulation are covered by this form. However, there are some exceptions. To know moreabout the forms of commands, refer to the DISPLAY III User Manuals. You will gain moreinsight in the following sections about use of the command structure.

MODELING WITH SESSION FILES

This useful feature for DISPLAY III allows you to write an ASCII session file input for themodeling session and execute in the batch mode for speedy modeling. The session files areautomatically generated during an interactive session and reside in the working directory asDSP##.SES where ## is a numeric string showing the latest ID of the session file. Keeping thesession files for future use is a smart way of saving a model since these files are relatively small.Experienced users modify the session files to create a model in case of mistakes in previoussessions and then create the model in the batch mode. This saves time and effort for the analyst.

Variable

8/12/2019 emagtm



3-16

CONTROLS OF GRAPHIC DISPLAY

As a user you will have control over the graphics display as to what is displayed on the screenand how it is displayed. The following controls are available:

a) LABELS: These are the IDs assigned to an entity. In most cases you want the program toautomatically assign these numbers. You may display these IDs along with the graphicsrepresentation or you may turn them off.

b) SIZES: The screen size of symbols for certain conditions such as boundary condition, forces,etc. can be controlled by the user.

c) COLOR: Each entity in the program has a unique default color. You may change thesecolors if needed.

d) CURVE AND SURFACE PLOTTING: You may increase the segmentation for plotting

purposes. High values of segmentation will take more time but will draw much smootherlines and surfaces when they are curved.

e) WINDOW/PAN/UNWINDOW: You may zoom into any part of the model to investigatelocal areas of interest. You may also slide or pan a window to view other local areas withoutzooming out.

f) VIEWING TRANSFORMATION: The program offers various options for orienting themodel to obtain the best possible view. You may use continuously changing views or storeyour own selected views to get the best possible views.

g) HIDDEN LINE REMOVAL/BOUNDARY LINE/SHADED IMAGE: To enhance modelvisualization you may obtain plots with hidden lines removed. You may also obtain modelswith only boundaries. This helps locate unwanted cracks in the model.

h) POST PROCESSING: Post processing features within DISPLAY III allows you to readanalysis results files and plot graphs, deformed geometry and contour lines, etc.

8/12/2019 emagtm


NISA/ EMAG Training Manual DISPLAY III – Basic Options for Geometric Modeling

4-1

CHAPTER 4

DISPLAY III — Basic Options for Geometric Modeling

The DISPLAY III basic commands for geometric modeling are described in this section. Thefirst thing to learn will be the ‘entities’ that are supported in the program. These entities arecreated, moved, copied, manipulated and edited through the different operations of the program.The entities can be grouped within different headers in terms of their use as following:

a) Geometric entities: These are entities which are used in the creation of a geometric model.The following are worth mentioning:

GRD: Grids are points in 3D space and are basic building blocks of the model.

LIN: Straight or curved parametric cubic lines created through joining of two or moregrids.

PAT: Patches are geometric entities which define a surface in 3D space. These arerepresented internally as a parametric bi-cubic surface. Elements or nodes for a plate model are created on this surface.

HYP: Hyperpatches are geometric entities which define a volume in 3D space. Theseare represented internally as parametric tricubic solids. Solid meshing is createdon these entities to create a 3D solid model.

b) Plane Primitives: These are analytically defined 2D shapes which are incorporated within

the program to speed up the modeling process. You can extract geometric entities directlyfrom the primitives and it saves a good amount of time. The following plane primitives arecurrently available in DISPLAY III.

CIR: These are circular shaped primitives to create ellipses, circles and annular rings.

RCT: These are rectangular shaped plane primitives to facilitate creation of rectanglesand squares within the program.

c) Solid Primitives: These are 3D shapes in the program which can be created instantaneously.Geometric entities can be extracted from these primitives for easy modeling.

CYL: Defines shapes of solid cylinder primitives.

SPH: Defines shape of solid spherical primitives.

CON: Defines shape of solid cone primitives. The cones may be truncated, if desired.

CUB: Defines shape of solid parallelepiped primitive.

8/12/2019 emagtm


DISPLAY III – Basic Options for Geometric Modeling NISA/ EMAG Training Manual

4-2

TOR: Defines shape of solid torus primitives to create circular or elliptical shaped torusgeometry.

WED: Defines solid wedge primitives.

PRY: Defines pyramid shapes. The base is defined as an equilateral n-side polygonspecified by its circumcircle or the radius of the inner circle tangent to all sides.

ROD: Defines solid rods with two end holes.

d) Other Entities: Within this subgroup we include special entities which can be created,moved, copied, manipulated and edited within the program.

LCS: The program offers three fundamental coordinate systems: cartesian, cylindricaland spherical, as global coordinate systems. You may create your own local

coordinate system oriented anywhere in space to facilitate model generation.Local coordinate systems may also be created for imposing load and boundaryconditions at some cases. Local coordinate systems are treated as entities whichcan be created, moved, copied, manipulated and edited by the program. There arevarious ways to create a local coordinate system. You should refer to theDISPLAY III User’s Manual for more information.

WPL: A workplane is an infinite plane in 3D space and is designed to facilitate thecreation of planar geometry with maximum use of mouse or other pointingdevices. The workplane can be cartesian or polar type and local cartesian orcylindrical coordinate systems can be defined. Construction points are drawn on

a workplane at increments of local dx and dy distances and the user picks upconstruction points simply by picking the points by the mouse. The density ofinternal construction points as well as the origin and extent of a workplane is usercontrolled. Using workplanes may be a rewarding experience in modeling.

LAY: Layers are used to group some entities of the model under a layer name and thencopied, moved, manipulated or stored. This feature of DISPLAY is extremelyuseful while modeling a large problem.

The DISPLAY functions listed below are global in the sense that they can be used on all of theabove entities (excepting layers). These are the most frequently used options and you may want

to familiarize yourself with their positions in the menu structure. Some of these functions arealso available through the hot buttons. If you prefer to use the command mode, you may want tofind out the command syntax from the DISPLAY manual and keep a copy next to your modelingworkbench.

8/12/2019 emagtm



4-3

Options for creation or modification of entities:

ADD: Create new entities by providing related data.

TRS: Create new entities by translating existing entities.

TRSM: Modify existing entities by translating (moving) them.

ROT: Create new entities by rotating existing entities about an axis.

ROTM: Modify existing entities by rotating (moving) them.

MIR: Create new entities by mirroring existing entities about a plane.

MIRM: Modify existing entities by mirroring (moving) them.

SCL: Create new entities by scaling existing entities.

SCLM: Modify existing entities by scaling (moving) them.

Options for entity manipulation and image enhancement:

SRH: Search for existing entities and report the database status.

ERA: Erase entities from the screen and remove them from the active set only.

COL: Change color of existing entities for all future plotting.

PLO: Plot entities and add them in the active set.

DEL: Delete existing entities from the database.

LAB: Change label status to turn on/off displaying ID numbers of entities.

NEC: To set new entity color.

SIZ: To set symbol size of entities.

DIS: To find distance between two entities.

DIR: To show parametric direction of geometric entities.

REV: To reverse parametric directions.

In the following pages, you will find a summary of commonly used commands which may beused to create, manipulate and edit different entities.

8/12/2019 emagtm



4-4

GRIDS (GRD):

General command format (some exceptions apply):

GRD, Option, Input ID, Output ID, Data

Option Description

ADD Create grids by specifying coordinatesWPL Create grids by picking points on workplaneLIN Extract grids from endpoints of existing linesPAT Extract grids from corners of existing patchHYP Extract grids from corners of existing hyperpatchCIR Create grid at the center of an existing circleRCT Create grid at the corners of existing rectangleCUB Create a grid at the corners of existing cubeSPH Create a grid at the center of existing sphereCYL Create grids at the base and top center of cylinder

CON Create grids at the base and top center of a coneTOR Create a grid at the center of an existing torusPYR Create grids at the corners of a pyramidWED Create grids at the corners of a wedgeROD Create grids at the end points of a rod NOD Create a grid at the location of a nodeELE Create grids at the corners of an elementCCL Create a grid at any position of a lineCCP Create a grid at any position of a patchINT Create a grid at the intersection of two lines

LPI Create a grid at intersection of a line and patchTRSM Translate an existing gridROTM Rotate an existing grid about an axisMIRM Mirror an existing grid about a planeSCLM Scale an existing grid about a pointTRS Create a grid by translating an existing gridROT Create a grid by rotating an existing gridMIR Create a grid by mirroring an existing gridSCL Create a grid by scaling a grid about a pointSRH Search for a grid or overall grid statusERA Erase a grid from the active set

COL Reassign color to a set of gridsPLO Plot one or a number of gridsDEL Delete one or many grids from the databaseLAB Plot/not plot grid IDs on the screen NEC Set or change the color of gridsSIZ Change the size of the grid symbol on the screenDIS Find distance between grids

8/12/2019 emagtm



4-5

LINES (LIN):


LIN, Option, Input-ID, Output ID, Data

Option Description

2GD Create a straight line between two grids3GD Create a smooth curve through three grids4GD Create a smooth curve through four grids NGD Create a spline curve through a number of grids2ND Create a straight line between two nodes3ND Create a smooth curve through three nodes4ND Create a smooth curve through four nodes NND Create a smooth curve through a number of nodes

ARC Create an arc lineEXD Create a curve of extension2WP Create a line through 2 points on workplane NWP Create a spline on a workplaneBEZ Create a Bezier curveCNC Create conic curvesHLX Create helical curvesINV Create involute curvesPAT Create lines at the boundary edges of a patchHYP Create lines at the boundary edges of a hyperpatchCIR Create lines from the boundary curve of a circle

RCT Create lines from the edges of a rectangleCUB Create lines from the edges of a cubeSPH Create lines on the surface of sphereCYL Create lines on the surface of a cylinderCON Create lines on the surface of a coneTOR Create lines on the surface of a torusPYR Create lines from the edges of a pyramidWED Create lines from the edges of a wedgeROD Create lines from the edges of a rodELE Create lines from the edges of an element

2GL Create a line on an existing line connecting two grids2GP Create a line on a patch connecting two grids on itCCL Create a line on a line by parameters or cursorCCP Create a line on a patch by parameters or cursorINT Create a line at an intersection of two patchesFIL Create line at a fillet between two linesMER Merge two lines to form a linePBR Break a line into two by parametric values

8/12/2019 emagtm



4-6

GBR Break a line into two on a specified gridEXT Extend a line along its tangent at the endpointBLE Blend a set of linesTRSM Translate an existing lineROTM Rotate an existing line about an axis

MIRM Mirror an existing line about a planeSCLM Scale an existing line about a pointTRS Create a line by translating an existing lineROT Create a line by rotating a line about an axisMIR Create a line by mirroring a line about a planeSCL Create a line by scaling a line about a pointSRH Search for a line or line statusERA Erase a line from screen and active setCOL Reassign colors to a set of linesPLO Plot a lineDEL Delete a line from the databaseLAB Switch off/on the display of line Ids NEC Set or change the color of linesDIR Find parametric direction of a lineREV Reverse parametric direction of a line

PATCHES (PAT):

The general command format (some exceptions apply):

PAT, Option, Input-ID, Output-ID, Data

Option Description

3GD Create a triangular patch with 3 corner grids4GD Create a patch with 4 corner grids16GD Create a patch through a 4x4 grid mesh3ND Create a triangular patch with 3 corner nodes4ND Create a patch with 4 corner nodes16ND Create a patch through a 4x4 node mesh2LN Create a patch by joining two opposite lines3LN Create a patch by joining 3 lines parallel in space4LN Create a patch by joining 4 lines parallel in space NLN Create a skinning surface through N lines3ED Create a triangular patch with lines as its boundary4ED Create a patch with 4 lines as its boundaryARC Create a surface of revolutionGLI Create a surface by sweepingEXD Create a surface of extrusion

8/12/2019 emagtm



4-7

NOR Create a surface of offsetBEZ Create a bezier surfaceWPL Create a patch on a workplaneHYP Create patches at the boundary face of a hyperpatchCIR Create patches from a circle

RCT Create patches from a rectangleCUB Create patches from the faces of a cubeSPH Create patches from the surface of a sphereCYL Create patches from the surface of a cylinderCON Create patches from the surface of a coneTOR Create patches from the surface of a torusPYR Create patches from the faces of a pyramidWED Create patches from the faces of a wedgeROD Create patches from the surface of a rodELE Create patches at the boundary face of an element2LP Create a patch connecting two lines on existing patchCCP Create a patch with 4 corner points on existing patchMER Merge a set of patches to form another setPBR Break a patch into two at specified parametric locationBLE Blend a set of patchesORG Move C1 and C2 direction from one corner to anotherTRSM Translate an existing patchROTM Rotate an existing patch about an axisMIRM Mirror an existing patch about a planeSCLM Scale an existing patch about a pointTRS Create a patch by translating an existing patch

ROT Create a patch by rotating an existing patchMIR Create a patch by mirroring an existing patchSCL Create a patch by scaling a patch about a pointSRH Search for a patch or patch statusERA Erase a patch from the screen and active setCOL Reassign colors to a set of patchesPLO Plot a patchDEL Delete a patch from the geometric modelLAB Plot/not plot the patch ID numbers NEC Set a color for future patches NLIN Set the number of lines in a patch wireframe drawingEDG Highlight the edges of a patchDIR Indicate the C1 and C2 directions of a patchREV Reverse the parametric directions (C1 and C2)

8/12/2019 emagtm



4-8

HYPERPATCHES (HYP):

The general command format (some exceptions apply):

HYP, Option, Input-ID, Output-ID, Data

Option Description

2PA Create hyperpatch by connecting two patches3PA Create hyperpatch by connecting 3 patches parallel in spac4PA Create hyperpatch by connecting 4 patches parallel in spac NPA Create a skinning solid through N patches6PA Create hyperpatch with six boundary patchesARC Create a solid of revolutionGLI Create a solid of sweepEXD Create a solid of extrusion

NOR Create a solid of offsetCUB Create hyperpatches from a cubeSPH Create hyperpatches from a sphereCYL Create hyperpatches from a cylinderCON Create hyperpatches from a coneTOR Create hyperpatches from a torusPYR Create hyperpatches from a pyramidWED Create hyperpatches from a wedgeROD Create hyperpatches from a rodELE Create a hyperpatch from solid elementMER Merge a set of hyperpatches to form a new one

PBR Break a hyperpatch into two at parametric locationsBLE Blend a set of hyperpatchesORG Move the origin of hyperpatch from a corner to otherTRSM Translate an existing hyperpatch about an axisROTM Rotate an existing hyperpatch about an axisMIRM Mirror an existing hyperpatch about a planeSCLM Scale an existing hyperpatch about a pointTRS Create a hyperpatch by translating an existing oneROT Create a hyperpatch by rotating an existing oneMIR Create a hyperpatch by mirroring an existing oneSCL Create a hyperpatch by scaling an existing hyperpatchSRH Search for a hyperpatch or statusERA Erase a hyperpatch from the screen and active setCOL Reassign colors to a set of hyperpatchesPLO Plot a hyperpatchDEL Delete a hyperpatch from the geometric modelLAB Plot/not plot the hyperpatch Ids NEC Set the color of future hyperpatches

8/12/2019 emagtm



4-9

NLIN Set the number of lines in hyperpatch wireframe plotEDG Highlight the edges of a hyperpatchFAC Highlight the faces of a hyperpatchDIR Indicate the C1, C2 and C3 directions of a hyperpatchREV Reverse the parametric directions of a hyperpatch

LOCAL COORDINATE SYSTEM (LCS):

The general command format is (some exceptions apply):

LCS, Option, Input-ID, Output-ID, Data

Option Description

ADD Create LCS with 3 grids, 3 nodes or 3 coordinatesANG Create LCS by specifying origin and three rotationsVEC Create LCS by specifying origin and two vectors

All other options TRSM, ROTM, MIRM, TRS, ROT, MIR, SRH, ERA, COL, PLO, DEL, LAB,

NEC and SIZE are available for LCS. These are not repeated here and their purposes were

described before.

WORKPLANES (WPL):

The general command format is (some exceptions apply):

WPL, Option, Input-ID, Output-ID, Data

Option Description

ADD Create workplaneDEL Delete user created workplanesPLO Plot a workplaneSRH Search and highlight a workplaneERA Erase a workplaneTRS Translate a workplaneROT Rotate a workplane

MXT Modify extents of a workplaneMDN Modify grid density and grid reference of a workplaneMDS Modify display of a workplaneCOL Change color of a workplaneLAB Switch on/off workplane label plotting NEC Specify new color for future workplanes

8/12/2019 emagtm



4-10

PLANE AND SOLID PRIMITIVES:

CIRCLE (CIR):


CIR, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a circle by its center and radius2PN Create a circle by its center and circumference point3PT Create a circle by three circumference pointsELP Create an ellipseRIN Create a circular ring

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,PLO, DEL, LAB, NEC apply as previously described.

RECTANGLE (RCT):


RCT, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a rectangle by its center width and length

2PT Create a rectangle by its diagonal corners3PT Create a rectangle by its three cornersRIN Create a rectangular ring


CUBE (CUB):

General command format (exceptions apply):

CUB, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a cube by its center, length, width and length2PT Create a cube by its two diagonal corners3PH Create a cube by its 3 base corners and heightTUB Create a tubular cube

8/12/2019 emagtm



4-11


SPHERE (SPH):


SPH, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a sphere by its center and radius2PT Create a sphere by its center and circumference pointELP Create an ellipsoidCUT Create a truncated sphere

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,

PLO, DEL, LAB, NEC, NLIN apply as previously described.

CYLINDER (CYL):


CYL, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a cylinder by its center, radius and height2PR Create a cylinder by its base, top centers and radius3PH Create cylinder by 3 base circumference points and radiusELP Create an elliptical cylinder.TUB Create a tubular cylinder

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,PLO, DEL, LAB, NEC, NLIN apply as previously described.

CONE (CON):


CON, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a cone by its base center, radii and height2PR Create a cone by its base, top centers and radiiRHA Create a cone by its taper angleELP Create an elliptical coneTUB Create a tubular cone

8/12/2019 emagtm



4-12

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,PLO, DEL, LAB, NEC, NLIN apply as previously described.

TORUS (TOR):

The general command format (exceptions apply):

TOR, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a torus by its base center and radii2PR Create a torus by its center and radius pointELP Create an elliptical torusCUT Create a truncated torus

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,PLO, DEL, LAB, NEC, NLIN also apply as previously described.

PYRAMID (PYR):


PYR, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a pyramid by its base center, radii and height

RHA Create a pyramid by its taper angle3PR Create a pyramid by its base and top center and radiusTUB Create a tubular pyramid

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,PLO, DEL, LAB, NEC also apply as previously described.

WEDGE (WED):


WED, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a wedge by a corner and three edge length2PA Create a wedge by its sloping angle3PH Create a wedge by its three base cornersCUT Create a truncated wedge

8/12/2019 emagtm



4-13

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,PLO, DEL, LAB, NEC also apply as previously described.

ROD (ROD):


ROD, Option, Input-ID, Output-ID, Data

Option Description

ADD Create a rod by its 2 centers and the end axes2PV Create a rod by its start axis and direction vector3PT Create a rod by start axis and endpoint of end axisCUT Create an one-end rod

Other options such as TRSM, ROTM, MIRM, SCLM, TRS, ROT, MIR, SCL, SRH, ERA, COL,PLO, DEL, LAB, NEC, NLIN also apply as previously described.

8/12/2019 emagtm



4-14


8/12/2019 emagtm


NISA/ EMAG Training Manual DISPLAY III – Basic Options for Finite Element Modeling

5-1

CHAPTER 5

DISPLAY III — Basic Options for Finite Element Modeling

Once the geometric modeling is complete, finite element meshes are mapped on the geometricmodel and load and boundary conditions are imposed on the model. At the end of the process, aninput file for the solver is automatically generated by the program.

The basic entities for finite element modeling are ELEMENTS (ELE) and NODES (NOD).Elements and nodes are the building blocks of the discretized model and are created by themeshing operation.

The finite element mesh may be generated in one of the following ways:

1. AUTOMATIC MESH GENERATION (AUTOMESH): This process is used to create

finite element model from a purely geometric definition of the boundary of a structure.

Automatic mesh generation can be used to create meshing for the following types ofmodels:

a) For a 2 Dimensional geometry lying in one plane, meshes can be generated from simpleline models only. Only a merged boundary line is needed for the geometry. The program will automatically create a completely quad or tri-quad mesh according to theuser’s wish. The user may even specify linear or parabolic elements for meshgeneration. The program, by default, will create a non-uniform mesh by creating a finemesh at the location of sharp geometry changes and a coarse mesh at areas of uniform potential gradient. You can also control the meshing by selecting a finer meshing.

MOREOPTIONS

ORDER(Ist quad)

MESHSIZE

GRADEDSIZE

GLOBAL DENSITY (.8)LOCAL DENSITY

FEM

MESH

AUTOMESH

2DFLAT

ENTIREMODEL

As an example, let us consider automesh of a 2D arbitrary shape with local mesh control

(at local density prompt, enter 4/111/1)

8/12/2019 emagtm


DISPLAY III – Basic Options for Finite Element Modeling NISA/ EMAG Training Manual

5-2

The Geometry Consisting of Lines

The Resulting Mesh

8/12/2019 emagtm



5-3

b) For a 3 dimensional plate model, the geometry must consist of properly merged patches. The mesh generator will create quad or tri-quad mesh according to userrequest. It can also create linear or parabolic elements. The mesh will be non-uniformand properly graded. The user has the option of automatically making the generatedmesh even finer.

c) For a 3 dimensional solid model, the geometry must consist of patches enclosing total boundary. The generated mesh will consist of tetrahedrals or hexahedrals or mixture of both.

2. FINITE ELEMENT GENERATION (FEG) MAPPED METHOD: These are semi-automatic means of generating mesh on a geometric model. The FEG option is used togenerate a finite element mesh by mapping elements and nodes on geometric entities likeLINES, PATCHES and HYPERPATCHES. The mesh size may also be controlled by thezoom factor to obtain a finer mesh at a particular region. The FEG command supportsvarious options as shown below:

Option Description

BAR FEG a line patch to create bar/beam elements

QUA FEG a patch to create quadrilateral plate/shell elements

TRI FEG a patch to create triangular plate/shell elements

HEX FEG a hyperpatch to create hexagonal solid elements

WED FEG a hyperpatch to create wedge shaped solid element

TET FEG a hyperpatch to generate tetrahedral solid elements

SRH Searches a FEG table for a geometric entity

DEL Deletes a FEG table for a geometric entity

As an example, let us consider the QUA option to generate quadrilateral elements on a planesurface in the 2 dimensional space. The command syntax will consist of the following entries:

COMMAND SYNTAX

Entry No. 1 2 3 4 5 6 7 8

FEG QUA PAT-ID ELEM-ID NODE-IDS E1/E2 NKTP/NORDR/MID/PID R1/R2Variable

8/12/2019 emagtm



5-4

MENU SYNTAX

VlARIABLE/TOKEN DESCRIPTION


3 PAT-ID List of patches to be FEGed, i.e., on which finite(INPUT-PATCH-IDS) elements are to be generated.

4 OUTPUT-ELEM-IDS List of IDs for the generated elements.

5 OUTPUT-NODE-IDS List of IDs for the generated nodes.

6 E1/E2 The number of subdivisions in the U- and V- parametric directions, respectively.

7 NKTP The stiffness type of the NISA element to begenerated. (default=20, 3D general shell element).

NORDR The order of the elements generated. NORDR forthese element can be 1, 2 or 3 depending on NKTP.

MID (MATERIAL ID) Material index for the generated elements(default=1).

PID (PROPERTY ID) Property index for the generated elements(default=1).

8 R1/R2 The zoom factor in the U- and V- parametricdirection, respectively (default=1.0/1.0). Zoomfactor is the ratio of the length of the last element tothe length of the first element in a given direction.

FEM

MESHFEG OPTION QUADRILATERAL

INPUT-PATCH-IDSE1/E2

ORDERSTIFFNESS-TYPEMATERIAL-IDPROPERTY-IDR1/R2OUTPUT-ELEM-IDSOUTPUT-NODE-IDSEXECUTE (G0)

FEM Opt Menus

Current OptMenu-1

Current OptMenu-2

Operation Menu

Specify tokens

8/12/2019 emagtm



5-5

EXAMPLES

To create elements with NORDR=2, NKTP=102 (i.e., eight noded isoparametric elements) using patch 10 with material identification number equal to 1 , and applying zoom factors of 0.3 alongC1 direction and 0.4 along C2 direction, type:

FEG, QUA, 10, , , 2/4, 102/2/1/, 0.3/0.4

3. FINITE ELEMENT GENERATION WITH TOPOLOGICAL ZOOM (FZM):

This is an extension of the FEG command and automates the mesh refinement process.This allows you to create local high densities of mesh and make a smooth transition toareas where the mesh is coarse. The basic command structure is identical to that of theFEG command with a few extra options and a list of locations about which the mesh is to

be refined or ‘zoomed’.

8/12/2019 emagtm



5-6

4. FINITE ELEMENT GENERATION WITH AUTOMATED MESH TRANSITION (FAM):

The FAM command is used to generate a finite element mesh on patches andhyperpatches. The command structure is similar to that of the FEG command except thatin this command the user may specify the number of elements desired on each of the four

edges of the patch (and the 3rd parametric direction in the case of a hyperpatch). Thetransitions required to maintain compatibility of elements are automatically generated.You may also individually specify the zoom factors on each of the four edges of the patch(and the 3rd parametric direction for the hyperpatch).

The FAM command supports various options as shown below:

Option Description

QUA to FAM a 4-sided patch and create quad elementsTRI to FAM a 4-sided patch and create triangular elementsHEX to FAM a hpatch and create hexagonal elements

WED to FAM a hpatch and create wedge elements

As an example of the FAM option, let us use the QUA option to create elements on a planesurface in the 2 dimensional space.

To generate FINITE ELEMENT MESH on a patch:

• If you use FEG, you can chose how many elements to create in each direction. (The meshcan be described as A X B elements.)

• If you use FZM, you can create two or four times as many elements along a particular edge.

• FAM gives you an option to create different numbers of elements along all four edges of the patch. Thus, we can generate five elements along edge #1, four along edge #2, three alongedge #3 and two along edge #4. The program takes care of the transition.

COMMAND SYNTAX

Entry No. 1 2 3 4 5 6 7 8

FAM QUA PAT-I ELEM-I NODE-ID E1/E2/E3/E4/IEDT NKTP/NORDR/MID/PI R1/R2/R3/R

Variable

8/12/2019 emagtm



5-7

MENU SYNTAX

VARIABLE/TOKEN DESCRIPTION

Entry variable/(token) description

3 PAT-ID List of patches on which finite element generation(INPUT PATCH-IDS) with automatic mesh transition is to be performed

(referred to here after as ‘FAMed’).

4 ELE-ID List of IDs for the generated elements.(OUTPUT-ELEM-IDS)

5 NOD-ID List of IDs for the generated nodes.(OUTPUT-NODE-IDS)

6 E1/E2/E3/E4 The number of elements generated along edges 1, 2,3 and 4 respectively, of the patch.

IEDTR This is to control the transition inside the patch.Valid values are:= 0 - transition inside the patch= 1 - transition on the edges of the patch

FEM

MESH FAM OPTION QUADRILATERAL

INPUT-PATCH-IDSE1/E2/E3/E4

ORDERSTIFFNESS-TYPEMATERIAL-IDPROPERTY-IDR1/R2/R3/R4OUTPUT-ELEM-IDSOUTPUT-NODE-IDSEXECUTE (G0)

GEOMEntities Menu

Entity OptsMenu

Current OptMenu-1

Operation Menu

Specify tokens

8/12/2019 emagtm



5-8


7 NKTP The stiffness type of the NISA element to be generated.(STIFFNESS TYPE) (Default=20 for 3D general shell element).

NORDR The order of the elements generated. NORDR for theseelements can be1, 2 or 3 depending on NKTP.

MID (MATERIALID) Material index for the generated elements (default=1).PID (PROPERTY ID) Property index for the generated elements (default=1).

8 R1/R2/R3/R4 The zoom factor along edges 1, 2, 3, and 4 of the patch(default = 1.0/1.0/1.0/1.0). Zoom factor is the ratio of thelength of the last element to the length of the first elementin a given direction.

8/12/2019 emagtm



5-9

EXAMPLES

1. To FAM patch 1 to get 2nd order QUA elements with 4, 8, 8 and 4 elements on edges 1, 2,3 and 4 of the patch and assign material identification number 1, NKTP = 102 type and NORDR = 1:

FAM, QUA, 1, , , 4/8/8/4, 102/1/1/ or FAM, QUA, 1, , , 4/8/8/4/1, 102/1/1/

2. To FAM patch 1 to get 2nd order QUA elements with 4, 8, 10 and 4 elements on edges 1,2, 3 and 4 of the patch and assign material identification number 1, NKTP = 102, type and NORDR = 1 :

FAM, QUA, 1, , , 4/8/10/4, 102/1/1/ or FAM, QUA, 1, , , 4/8/10/4/1, 102/1/1/

transition inside the patch transition on the edges of the patch

8/12/2019 emagtm



5-10

MANIPULATION OF MODEL DATA:

The element and nodes created by the meshing operation are part of the ‘Model Data’ in finiteelement modeling. When a mesh is created by Automesh or FEG/FZM/FAM options, you neednot worry about node or element manipulation much. DISPLAY III, however, offers special

options to create, move, copy, clean, and edit these data. You may never need them, but they areextremely useful in special circumstances.

Node Manipulation

These options shown below:

Optio Description

ADD Create a node with given coordinate dataWPL Create nodes on a workplane

GRD Create nodes at grid locationsCLN Delete all unreferenced nodes from databaseMER Merge nodes within a user specified toleranceDLC Change the displacement local coordinate system of nodeDIS Find distance between two nodes

Other options such as TRS, TRSM, ROT, ROTM, MIR, MIRM, SCL, SCLM, SRH, ERA, COL,PLO, DEL, LAB, NEC, SIZ are also available for nodes and were previously discussed.

Element Manipulation

The available options also include options to verify the quality of the elements and are shown below:

Option Description

ADD Create elements individually by node connectivityREV Reverse nodal connectivity of existing elementsRN Reverse normals of a set of elements w.r.t anotherMPG Change linear elements to parabolic elementsMPR Change parabolic elements to linear elements

MO Modify element parameters and attributesBRK Split a 2D or shell type elements into 2, 3 or 4 elementsRGN Generate solid elements by translating shell elementsCGN Generate solid elements by rotating shell elementsSSG Generate solid elements by offsetting shell elementsDIX Calculate distortion index of elementsCHK Check skewness, warping, aspect ratio and angles of elements

8/12/2019 emagtm



5-11

NIS Verify that elements meet NISA requirements NOR Display normal vectors of specified elementsBND Boundary line plot of specified elements or whole modelPAI Paint elements based on material, properties or typeFAC Show element faces

CON Show element connectivity

In addition, other options such as TRS, TRSM, ROT, ROTM, MIR, MIRM, SRH, ERA, COL,PLO, DEL, LAB, NEC are available and were described in earlier chapters.

PHYSICAL PROPERTY SPECIFICATION

Finite element analysis requires physical properties to formulate stiffness matrix. These arematerial properties and will differ for different materials. Material properties are required in allthe elements.

Material properties are also defined through the NISA ‘form’ structure.

Material Properties:

When elements are created in DISPLAY III, a part of their data is in the material-ID. Thematerial-ID, serves as a link between the finite element entities and the actual property values.Required material property values depend on the type of analysis that will be performed.

Material properties are identified by labels. Following is a description of some labels requiredfor Electromagnetic analysis.

Electromagnetic Analysis:

EXX Dielectric permittivity in X direction

EYY Dielectric permittivity in Y direction

EZZ Dielectric permittivity in Z direction

MUXX Permeability in X direction

MUYY Permeability in Y direction

MUZZ Permeability in Z direction

SIXX Electric Conductivity in X direction

SIYY Electric Conductivity in Y direction

8/12/2019 emagtm



5-12

SIZZ Electric Conductivity in Z direction

NUXX Reluctivity in X direction

NUYY Reluctivity in Y direction

NUZZ Reluctivity in Z direction

For specifying material properties of elements using HEAT analysis, refer to the NISA/HEATTraining Manual.

The material properties are defined in FORMs as shown below:

In the menu mode the following path invokes the Material Property Form:

Material Property Form:

Figure 5.1 shows the Material Property Form. It shows one frame button and three pick buttons.

FE GENERATION FE MODEL DATA MATERIAL DATA

Figure 5.1 : Material Property Data

8/12/2019 emagtm



5-13

Frame button:

Pick this to quit the form.

Pick buttons:

Pick this to add a new material property specification to the DISPLAYdatabase. It invokes the Material Properties Add Form.

Pick this to see which materials have already been defined by you. It invokesthe Materials List Edit Form which lists defined Material Ids and names andlets you pick the one you want to examine or change.

Pick this to delete an existing material specification. It invokes the MaterialsList Delete form which lists defined Material IDs and names and lets you pickthe one you want to delete.

Pick this to get list of material properties available in last database.

Pick this to delete a material property from list of material properties availablein last database.

Quit

Add

List

Delete

Lstmat

Delmat

8/12/2019 emagtm



5-14

Material Properties Add Form:

Figure 5.2 shows the Material Property Add Form.

This form lets you modify or specify material properties for a material. If you are editing anexisting material, the form will show the existing material property values when it first comesup. If you are defining a new material all the fields will be blank. It has three frame buttons anda number of data fields.

Frame buttons:

Pick this to write the material properties to the Material File. The properties are stored under the material name entered in thecharacter field

Pick this when you are satisfied with the material propertiescurrently displayed in the form — it saves the materialspecification in the DISPLAY database and exits the form.

Pick this if you have made mistakes and want to reset all the valuesto those that existed when the form first came up.

Pick this to exit the form without saving the currently displayedmaterial specification.

SAVEMAT

OK

Reset

Quit

Figure 5.2 : Material Property Add Form

8/12/2019 emagtm



5-15

The database fields are:

Material ID: This is an integer field. Materials are uniquely identified by thisinteger. Thus if you modify this ID and pick OK — you are

specifying a new material. If the ID specified here already exists, youwill be prompted whether you want to overwrite the previousspecification.

Material Name This is a character field 12 characters long. It is for your referenceonly. DISPLAY does not check uniqueness of material names.

Material Property Value The rest of the form is made up of these real fields. The propertyname is indicated to the left of the fields. You do not have to specifyall the property values. Specify only those that are needed for yourintended analysis. Thus, if you are doing EFIELD analysis — ignore

the Permeability and Reluctivity properties.

Materials List Edit Form:

Figure 5.3 shows this form. Its function is to list IDs and names of currently defined materialsand to let you pick the one you want to edit or examine.

It has one frame button — Quit — which quits this form.

The rest of the form is made of pick buttons which are the material IDs. To the right of the ID pick buttons are the corresponding names of the materials. You can pick any of the IDs to edit orexamine the corresponding material specification. Picking one of the ID buttons invokes theMaterials Property Add Form initialized with the picked materials data.

QUIT

LIST OF MATERIALS

MATERIAL ID MATERIAL NAME

1

2

3

MAT_1

MAT_2

MAT_3

Figure 5.3 : Materials List Form

8/12/2019 emagtm



5-16

Materials List Delete Form:

This form is identical in appearance to the Materials List Edit Form. The difference is that picking any one of the Material ID buttons results in deletion of that material specification fromthe DISPLAY database.

ELECTROMAGNETIC SOURCES & BOUNDARY CONDITIONS

The type of sources and boundary conditions specified in the model data depend on the type ofanalysis being performed. DISPLAY III graphically displays all types of boundary conditions onthe model and they are defined by using the mouse. While Electromagnetic analysis may requirenodal potentials or elemental flux, current or charge densities, heat transfer may require nodal

temperatures. The following is a list of valid boundary conditions supported in the program forelectromagnetic analysis.

Option Description

SPF Nodal electrical or magnetic potentialsINI Nodal initial electrical or magnetic potential for transient

AnalysisEFL Electric flux density at specified element facesMFL Magnetic flux density at specified element faces

CHR Elemental Charge densityCUR Elemental Current densityPMA Elemental Permanent Magnet Coercive field strength

Note that electric or magnetic potentials, flux densities, and current, charge or coercive density

are specified in a different fashion. Each group of specified boundary conditions is identified by

a set ID number. Each set may contain one type of boundary condition applied on various nodes

or elements.

Once boundary conditions are specified, you may list, search, erase, plot or delete such sets usingdifferent options as shown below:

Option Description

SRH Search for boundary conditions under a setERA Erase boundary condition set from screen and active set

8/12/2019 emagtm



5-17

COL Re-assign a color to a boundary condition setPLO Plot a boundary condition set and keep it in active setDEL Delete a boundary conditions setLAB Control plotting of boundary condition set NEC Specify a new color for a boundary condition set

SIZ Set the plotting size of boundary condition set symbol

8/12/2019 emagtm



5-18

This page is intentionally left blank

8/12/2019 emagtm


NISA/ EMAG Training Manual DISPLAY III – Miscellaneous Options

6-1

CHAPTER 6

DISPLAY III - Miscellaneous Options

This section describes various other features of DISPLAY III. DISPLAY III offers various other powerful options for model generation. They will be briefly described in the following pages.

MODEL VIEWING:

DISPLAY III offers various convenient options for easy model viewing. These features includeseveral display options such as geometry scaling, model shrinking, hidden line plot, boundaryline plot, light source shading etc. Standard views such as top, bottom, front, back, side andisometric views can be invoked by simply clicking the mouse on hot buttons. There are also userdefined views that can be stored in the program and the model can be plotted at those anglessimply by the hot buttons. The following VIEW options are available in DISPLAY III:

Option Description

SCL Set model scaling option.SHK Set element shrink option.SHG Set the geometry shrink option.HID Set the hidden line plot mode for elements on.HDN Set the hidden line plot mode for geometry on.BND Set the boundary line plot mode on.

The following standard views are available in DISPLAY III.

Option Description

TOP Set viewing angles to top view X rot/Y rot/Z rot=90/0/0BOT Set viewing angles to bottom view (-90/0/0).FRON Set viewing angles to front view (0/0/0).BACK Set viewing angles to back view (0/180/0).LEFT Set viewing angles to left-side view (0/-90/0).RIGHT Set viewing angles to right side view (0/90/0).ISO Set viewing angles to isometric view (-45/0/-45).ANG1 User defined angle set 1.

ANG2 User defined angle set 2.ANG3 User defined angle set 3.ANG4 User defined angle set 4.ABS Set viewing angle to user defined absolute rotations.REL Set viewing angle to user defined relative rotations.SCR Set viewing angles by rotating about screen axes.EYE Set viewing angles by specifying the eye position.

8/12/2019 emagtm


DISPLAY III – Miscellaneous Options NISA/ EMAG Training Manual

6-2

MODEL PARAMETERS

There are several parameters that may need changing depending on the modeling session. Forexample, if the nodal dimensions are too large or too small, the default tolerance parameters fordistance may need to be changed for better modeling practices. These options are available

under SET/SHOW top bar menu. The available options are:

Option Description

TOLD Set tolerance for distance to check equality of points.TOLC Set tolerance for picking entities on screen.SNAP Set snap mode for workplane operations.DWPL Set default workplane ID for workplane operation.ANG1 Assign user defined viewing rotation angle 1.ANG2 Assign user defined viewing rotation angle 2.ANG3 Assign user defined viewing rotation angle 3. NSEG Set number of segments for display of curved lines.CPAI Set point color indexes.LTHK Set line thickness for curve plotting. NCSEG Set number of circular segments to plot circles.CHIDE Set element fill color for hidden line plots.MOUSE Set the definition of mouse.LABA Set the label-ID plotting status for all entities.SCRL Set number of scroll lines in dialogue area.WAIT Set the wait time for PAUSE command in time units.COL Show the current device color indexes.

LAYERS & SETS

DISPLAY III allows you to group certain entities of the model under a layer name and storethese layers in the database for future use. In a similar way, certain entities may be lumped intoa set and given a set ID number.

Layers are identified by a layer name of up to 12 characters and there is no limit on the numberof layers that can be stored in the program. Layers offer various options for creating, modifying,manipulating and editing. These options are listed below:

Option DescriptionADD Create a layer with user defined group of entities.SRH Search for existence of a layer.ERA Erase all entities belonging to a layer from active set.COL Re-assign a color to a particular layer.PLO Plot all entities belonging to a layer.DEL Delete a layer name from database.

8/12/2019 emagtm



6-3

MISCELLANEOUS COMMANDS

There are various commands available which are not entity related but perform global functions.The following options are used in DISPLAY III:

CLIN Position dimension lines on screen with/without arrow heads.

CTXT Position text on screen for user defined texts/titles.

END End the current modeling session and save database file.

ERASE/CLR Erase plotting screen and reset active set to NULL.

HCPY Get a hard copy (screen dump) of present screen.

HELP Get general help or specific DISPLAY command help.

LOAD Load the last saved database file via 'END' command.

MENU Change the command mode to menu mode.

NEW Start a new modeling session.

NISA Define NISA data groups via screen editor.

ORN Specify viewing angle with cursor on viewing aids.

PAN Specify center point of region for panning operation.

PAS,ON Pause program until further keyboard entry.

PAS,TIME Pause program for user-defined time units.

PLOT Plot current active set.

PLOT, ACAD Plot active set and generate AUTOCAD.DXF file.

PLOT, ACT Plot the current active set with remapping.

PLOT, ALL Plot all entities in the database.

QUIT Exit from DISPLAY program.

REG Prompt for two points where future plots are directed.

RESET Refresh graphics area for plot and global menu area.

8/12/2019 emagtm



6-4

STATUS Get a quick listing of database entities.

SYSTEM Allow user enter operating system commands.

UNDO Undo the last database changes.

UNW Un-window the last PAN or WIN command action.

WIN Prompt user for window creation and redraw entities.

TEXT EDITING IN DISPLAY III

The pre-processor offers a screen editor within DISPLAY III to edit text files. This is aconvenient editor to perform editing of the NISA input file without getting out of DISPLAY III.The editor comes equipped with frame button search, save, exit and other standard options for a

good screen editor.

MACRO PROGRAMMING IN DISPLAY III

A macro is a set of statements (program) which can be executed in DISPLAY III to modelgeometries in terms of variables and thereby creating parametric models by inserting differentvalues for variables.

Macros use control structures in a fashion similar to any high level programming language. Ifyou enjoy programming, macros will let you add your own commands to DISPLAY.

Macros can be written with all DISPLAY commands and also programming commands likeLABEL, GOTO, CONTINUE, LET, IF, ENDIF, REPEAT, BREAK, LABEL, IF-THEN, ELSE,ENDMACRO.

FILE STRUCTURE:

This section is devoted to explaining the file structure and understanding the significance ofdifferent files and their formats for effective use of the programs. Some of the important filesused for pre\post-processing and analysis are explained below. It is a good practice to use theseextensions when naming a file.

DATABASE FILE (DBS): This file contains the geometry and finite element information for amodel in the binary format. This file is easily retrievable and it is good practice to save such afile during the progression of an interactive session in DISPLAY III thereby avoiding data lossdue to a sudden shutdown of the system.

NEUTRAL FILE (NEU): This file contains either all or selective geometry and finite elementinformation for a model in the ASCII format. Even though this file is not as easily retrievableand occupies more hard disk space than DBS files, it does offer may advantages. The user can

8/12/2019 emagtm



6-5

edit a neutral file to make minor changes in the mode. Also, this file is easily transferred fromone computer to another since it is in ASCII format. One major advantage of using a neutral fileis that one can break up a complicated model into different parts and model each partindependently. The user can then read the neutral file associated with each part, one afteranother, into the pre-processor to create the complete model. Neutral files can be written as both

DISPLAY III format as well as DISPLAY II format.

NISA INPUT FILE (NIS): This file is the actual NISA data file which is required for executionof any of the NISA programs. This file can be generated directly from DISPLAY III and thenviewed and edited within it. Since this file is in ASCII format, it is a good idea to view and checkthis file before submitting it for a NISA execution run. This file can also be read into the pre- processor to review and/or modify the model. You are encouraged to become as familiar as possible with the structure of this file since a thorough understanding of this file is necessary tomaster finite element analysis with the NISA family of programs.

SESSION FILE (SES): The pre- and post-processing operations are performed interactively by

the user. Also, the same programs can be executed in a batch mode through the use of sessionfiles. In the pre-processor DISPLAY III, after each session is over the program automaticallysaves a file which has a default name such as DSP#.SES. The character '#' designates the sessionnumber. In post-processing with DISPLAY III, similarly session files are saved as POSTSES.#.These session files contain all the commands that were entered during the session. Often, itseems logical to rename these files and preserve them because they can be read into the pre/post- processor to recreate the model, step by step. These session files are in ASCII format and can,therefore, be edited.

OUTPUT FILE (OUT): This file contains the results from a NISA analysis in ASCII format.This is a standard output file which contains information such as displacements, stresses,reaction forces, strain energy, etc. This file also contains any warning or error messagesgenerated during the analysis. If a NISA execution run crashes, the cause for the programtermination is usually fully documented in this output file. The user has complete control overthe size of this output file through the use of the *SET and *PRINTCNTL cards.

POST PROCESSING FILES (*26.DAT and *39.DAT): These files are the binary output files,which are used in the DISPLAY III post processor DISPLAY-POST for viewing and printing thegraphical results of the problem. These files are saved through the 'SAVE=' and 'FILE='executive cards at the beginning of the NISA input file. For example, in the first modelingsession of this tutorial, files EFIE26.DAT and EFIE39.DAT may have been saved for post- processing because of existence of the following executive cards in the NISA input file, whichwas saved at the end of the modeling session.

SAVE=26,27FILE=EFIE

The file EFIE26.DAT contains geometry information of the model and solutions. At present thefile 39 is not used, but it will be utilized in future versions.

8/12/2019 emagtm



6-6

TEMPORARY FILES (TMP): These are temporary files created during execution of a NISA job and are automatically deleted at the end of a successful NISA run. These are basicallyscratch files which are opened during the NISA analysis to store information such as the elementmass matrices, element stiffness matrices, etc. The information in these files is in binary format

and therefore, these files are of no interest to the user. If a NISA job suddenly crashes becauseof some error, you will find these files in the work directory.

To summarize, the NISA/DISPLAY file structure can be represented as shown in Figure 6.1.

DBS B

NEU A

NIS A

SES A

SCN B

NIS A

OUT A

26 / 39 B

TMP B

DISPLAY III

EMAG

( SOLVER )

8/12/2019 emagtm



6-7

SES A

SCN B

26 / 39 B

DISPLAY II

( POST )

Fig. 6.1

8/12/2019 emagtm



6-8


8/12/2019 emagtm


NISA/ EMAG Training Manual Low Frequency

7-1

CHAPTER 7

LOW FREQUENCY ANALYSIS

Theoretical Overview

Electromagnetism deals with the study of electric and magnetic fields. These fields are vectorquantities and their behavior is governed by a set of laws known as Maxwell’s equations.Originally, Maxwell’s equations are a set of four integral equations resulting from such basiclaws as Faraday’s Law, Ampere’s Law and Gauss’ Law. Maxwell’s equations in integral formsgovern the interdependence of certain field and source quantities associated with regions inspace, i.e., contours, surfaces and volumes.

However, the integral forms of Maxwell’s equations do not permit the direct study of theinteraction between the field vectors and their relationships with the source densities atindividual points. As a result, a set of Maxwell’s equations in differential form are derived using

the Stoke’s and Divergence theorems. Hence, in finite element analysis, the Maxwell’s equationsin differential form are used.

Maxwell’s Equations in Differential Form

The usual electromagnetic field equations are expressed in terms of six quantities. They are:

E ( r, t) , the electric field strength (V/m) H ( r, t) , the magnetic field strength (A/m) D ( r, t) , the electric flux density (C/m2) B ( r, t) , the magnetic flux density (Wb/m2)

J ( r, t) , the electric current density (A/m2

)ρ ( r, t) , the electric volume charge density (C/m3)

and they obey the following Maxwell’s equations:

t

B E

∂∂

−=×∇!

!

……(7.1)

t

D J H

∂∂

+=×∇!

!!

……(7.2)

ρ =•∇ D!

…..(7.3)

0=•∇ B!

…..(7.4)

8/12/2019 emagtm


NISA/EMAG Training Manual Low Frequency

7-2

In addition to the above expressions, one needs equations specifying the characteristics of the

medium in which the field exists. These equations are known as the constitutive relations.

The constitutive relations can be written simple as

D = ε E where ε = permittivity (F/m) (7.5) B = µ H where µ = permeability (H/m) (7.6) J = σ E where σ = conductivity (mho/m) (7.7)

In free space void of any matter, σ = 0, ε = ε o and µ = µ o , where, µ o = 4 π x 10-7 H/mε o = 8.854 x 10-12 F/m

The quantities ε, µ and σ are not necessarily simple constants, a notable exception being the

case of ferromagnetic materials for which B – H

relationship may be nonlinear. Furthermore, ε and µ may represent anisotropic materials, in such case the constitutive constants have to bewritten as tensors, i.e.,

Where

The Maxwell’s equation with the constitutive relations include the information contained in theequation of continuity

0=∂∂

+•∇t

J ρ !

…..(7.10)

E D!!

ε = …..(7.8)

H B!!

µ = …..(7.9)

=

z

y

x

ε

ε

ε

ε

00

00

00

;

=

z

y

x

µ

µ

µ

µ

00

00

00

8/12/2019 emagtm



7-3

The Finite Element Approach for Solving Differential Equations in terms of Potentials

Analysis of the electric and magnetic fields in electromagnetic devices are performed by solvingdifferential equations for potential quantities obtained from Maxwell’s equations. In this section,the behavior of the electromagnetic fields at low frequencies are investigated.

Under the limits of the static case (i.e., ∂/∂t = 0), Maxwell’s equations become decoupled; i.e. theelectric and the magnetic fields become independent of each other. Then the electric field is produced either by static charges or by the steady flow of currents. Similarly, the magnetic fieldis produced either by the currents flowing in the conducting regions or by the permanentmagnets.

At relatively low frequencies, i.e. when the rate of time variation are sufficiently slow, the

displacement-current term ∂D/∂t in the Maxwell equation (7.2) can be neglected. Such anassumption is also valid when the linear dimensions of the device are small compared with theelectromagnetic wavelength. This is invariably the case at power frequencies. Then if theconduction in the media is sufficiently high, both electric and magnetic fields interact with eachother.

Once the differential equations are obtained, the potential quantities that determine the electricand magnetic fields are solved by the finite element method. It is well known that the satisfying adifferential equations in any region having Neumann and Dirichlet boundary conditions, isequivalent to extremizing a functional which gives the total energy of the region of interest.

Different types of Analysis at Low Frequencies

Electrostatic Fields

Electric fields and potentials due to either stationary electric charges (electrostatic analysis) ordue to steady flow of electric charges ( steady current flow analysis) are covered here.

Electrostatic Analysis

By setting ∂/∂t = 0, in equation (7.1), one obtains

And by making use of the fact that curl of gradient of any scalar function is zero one can write

0=×∇ E !

……(7.11)

8/12/2019 emagtm



7-4

Where φ is known as the electrostatic potential (V). Then, by substituting (7.12) and (7.5) into

(7.4) one obtains the Poisson’s equation for the electric potential.

A space-charge distribution is regarded as given and the boundary condition will often be of theDirichlet type where the potential φ being specified on some boundary surfaces. The natural boundary is of Neumann type, that is, ∂φ/∂n = 0.

The total stored energy is given by

The capacitance of the device is calculated using either

Where V is the voltage difference applied; or

Where Q is the total charge on the conductor and is given by

Where ρs is the surface charge density on the conductor surface S.

Steady Current Flow Analysis

When dealing with conducting materials, the differential equation for the electric scalar

potential can be obtained by making use of the Ohm’s law

φ ∇−= E !

……(7.12)

ρ φ ε −=∇•∇ )( ……(7.13)

)14.7(......21 2 Ω= ∫ Ω

d E W e!

ε

)15.7(......2

2V

W C e=

)16.7(.......2

2

eW

QC =

)17.7(......∫ Ω

=s

sS d Q ρ

)18.7(...... E J !!

σ =

8/12/2019 emagtm



7-5

Where J is the conduction current density and σ is the conductivity of the material.

Consequently, by substituting (7.18) and (7.12) into equation (7.10) and setting ∂/∂t = 0 ,

one can form the Laplace equation

The boundary specification would again commonly be Dirichlet or the natural boundary

condition.

The total dissipated power in the device is given by

And the conductance is calculated using

Where V is the voltage difference applied.

Magnetostatic Fields

Here, the steady magnetic fields produced by the current carrying region and permanent

magnets are stated.

From equation (7.3) and making use of the fact that the divergence of the curl is zero, one

can write

Where A is known as the magnetic vector potential (Wb/m). The differential equation for

the magnetic vector potential A is obtained by substituting (7.22) into (7.2) and then

setting ∂/∂t = 0 ,

)19.7(......0)( =∇•∇ φ σ

)20.7(......

2

Ω= ∫ Ω d

J

Pd σ

!

)21.7(......2

V

PG d =

)22.7(...... A B

!!

×∇=

)23.7......( J A!!

=×∇×∇ ν

8/12/2019 emagtm



7-6

Where ν = 1/µ is the reluctivity of the material (m/H). By using vector identities and

the Coulomb’s condition (∇ • A = 0), equation (7.23) can be reduced to the vector

Poisson equation

The total stored magnetic energy is given by

And the inductance of the device is given by

Where I is the current in the conductor and is obtained using

Where J is the current density on the conductor cross section St .

Magnetostatic Analysis for the Translation symmetry Case

For this case, when the current density J and the magnetic vector potential A possess onlylongitudinally directed components; the vector Poisson equation degenerates to its scalarcounterpart

Current density is regarded as given and the boundary condition is of the Dirichlet type where A is specified on some boundary surfaces. The natural boundary condition is Ht = 0.

Magnetostatic Analysis for the Axisymmetric Case

For the axisymmetric case, both the current density J and the magnetic vector potential A possess only θ components; equation (7.23) reduces in the rz plane to

)24.7(......)( J A!!

=∇•∇ ν

)25.7(......2

1 2

Ω= ∫ Ω

d BW h!

ν

)26.7(......2

2

I

W L h=

)27.7(......∫ •=t S

sd J I !

!

)28.7(......)( J A =∇•∇ ν

)29.7(......)(1

J z

A

zr

Ar

r r −=

∂∂

∂∂

+

∂

∂∂∂

ν γ

8/12/2019 emagtm



7-7

The magnetic flux density lies in the rz plane and is related to A by

One can see that the equipotential lines of r A coincide with the flux lines.

Magnetostatic Analysis for the three dimensional Case

The calculation of magnetostatic fields in three dimensions using finite elements can be carriedout using either the full vector potential approach or the reduced scalar potential approach. Thereduced scalar potential method has the inherent advantage over the vector potential method of

having fewer unknowns per node, however, it suffers from what is so-called as the cancellationerror in iron materials near the current carrying regions. Both methods are available in NISA/EMAG for the users to choose the appropriate method for their applications.

The vector potential approach

Governing equation is 7.23. Current density is regarded as given and the boundary condition ofthe Dirichlet type where A is specified on some boundary surfaces.

The reduced scalar potential approach

In many cases the magnetic field intensity H can be separated into two parts

H = H s + H m (7.31)

Where H s is directly the result of the current sources and H m is the magnetization enclosed in thematerial. H s is entirely independent of the material and can be obtained from the Biot-Savartlaw. The vector H m is irrotational, i.e. ,

∇ × H m = 0 (7.32)

Hence, H m can be written as

Where φm is the reduced magnetic scalar potential. A reduced scalar differential equation for the potential can be obtained by using equations (7.31), (7.2) into (7.4) and is given by

( ) )30.7(......

1

)(

1ˆ

^

Ar r r

z Ar zr

r B

∂

∂

+∂

∂

−=

)33.7(......mm H φ ∇−=

( ) ( ) )34.7......(sm H µ φ µ •∇=∇•∇

8/12/2019 emagtm



7-8

Where µ is the permeability of the media.

Again, a space-current density is given and the boundary condition is of the Dirichlet type.

Nonlinear magnetic materials

The problem of nonlinearity in magnetostatic analysis can arise when dealing with materialswhose reluctivity depends on the magnetic field. Applications for material nonlinearities areevident for example in performing magnetic field computations in electric machines while takinginto account the saturation effects of the magnetic materials.

To attempt solution of Equation (7.23) by finite element methods, a suitable functional must first be defined. Assuming that the B – H curve for the magnetic material to be monotonicallyincreasing, then the quantity

is recognised as the stored energy density in the magnetization of the material.

Solution Scheme :

The nonlinear magnetostatic analysis is implemented using an iterative procedure based on the Newton-Raphson method.

For nonlinear magnetostatic problems, the stored energy is given by

And the stored coenergy is given by

Problems involving permanent magnets

Here, the solution of problems involving permanent magnet materials with magnetization isconsidered. It is of the form

B = µ ( H + H c ) (7.38)

∫ •= )35.7(.......)( Bd B H nξ

)36.7(......0

Ω

•= ∫ ∫

Ω

d Bd H W

B

h

)37.7(......0

Ω

•= ∫ ∫

Ω

d H d BW

H

c

8/12/2019 emagtm



7-9

Where H c is the coercive field strength of the material. The type of magnetization characteristiccorresponding to (7.38) is shown in Figure (7.1).

B

Nonlinear Permanent Br (remenance)Magnetic Material

Linear PermanentMagnetic Material

- H c H

( magnetic coercivity)

Figure 7.1 Magnetization characteristic for a permanent magnet material.

The vector potential formulation for permanent magnet materials is given by

For linear permanent magnet materials, the material property (reluctivity) is given by

Where H c is the magnetic coercivity and Br is the remenance. While for nonlinear permanentmagnet material, the material property is defined through its demagnetization B – H curveshifted to the first quadrant by H c as shown in Figure (7.2)

)39.7......( J H A c

!!!

=×∇−×∇×∇ ν

)40.7......(r

c

B

H =ν

8/12/2019 emagtm



7-10

B

Actual Demagnetization

Curve B – H Demagnetization Curve

- H c H c H

( magnetic coercivity)

Figure 7.2 B – H curve for nonlinear permanent magnet materials.

Analysis of Time-Varying Magnetic Fields

In electromagnetic devices, time-varying currents give rise to time-varying magnetic fields,which in turn induce currents in the conducting materials, called eddy currents. If these currentsare large enough, they can cause numerous problems to the device of interest. In general, eddycurrent time-fluctuation rates are low enough for the simplification of Maxwell’s equations by

neglecting the displacement current ( i.e.,

∂ D

/∂t = 0 ). The differential equation for the magneticvector potential A is then given by

Where ν is the reluctivity of the device and σ the conductivity of the materials present.

The induced eddy currents are given by

For the two-dimensional case ( i.e., J s flowing only in the axial direction ), equation (7.41)reduces to

)41.7(......)(s J

t

A A

!

!

!

=∂∂

+×∇×∇ σ ν

)42.7(......t

A J

e ∂

∂

−= σ

)43.7(......)(s J

t

A A −=

∂∂

−∇•∇ σ ν

8/12/2019 emagtm



7-11

Equation (7.43) is applicable to the general two-dimensional time-varying case where nonlinearmagnetic materials may be present.

Transient Field analysis

In the case of transient excitation J s(t), equation (7.43) is solved using the time integrationmethod. Three different types of time integration schemes are available and are controlled by thetime integration parameter α :

1. Trapezoidal ( Crank-Nicholson ) (α = 0.5 )2. Galerkin (α = 0.67 )3. Backward difference ( Implicit Euler ) (α = 1.0 )

The variation of the excitation can be represented by piecewise linear curves of time vs.amplitude. For accurate results it is important that the time-step ∆t should be sufficiently fine.

Hence, the size of the time steps can be fixed or varying. This time step method can also dealwith nonlinear problems.

Time-Harmonic Field Analysis (Magnetodynamic Analysis)

When considering the case in which J s represents a time-harmonic excitation at frequency ω (rad/s) and ν corresponding to a linear material (steady with time), equation (7.43) can be writtenas

Where A and J s are now complex quantities.

The impedance per unit length of the device is given by

Z = R + j ω L (7.45)

R is the resistance of the conductor and is calculated using

Where Pd is the dissipated power in the conductor and I is the total current in the conductor. L isthe inductance of the conductor and is calculated using

Where Wh is the total stored energy.

)44.7(.......)( s J A j A −=−∇•∇ σ ω ν

)46.7(......2

I

P R d =

)47.7(......2

2 I

W L h=

8/12/2019 emagtm



7-12

Note : In magnetodynamic analysis, the magentic fields penetrate into the conductor only to acertain depth causing the currents to concentrate near the surface of the conductor (skin effect).This depth parameter is known as the skin depth and is given by

Consequently, in order to capture the skin effect, the mesh in the conductor region needs to befine ( ≈ 1/3 δ ).

Force and Torque Calculations

Many electromagnetic devices are designed to produce mechanical force or torque. The forceand torque calculation method used in NISA/EMAG is based on the virtual work principle.

Force calculations

The virtual work expression for force is given by

Where s is the displacement parameter in the force direction and W is the work or energy. Oneway to approximate equation (7.49) is

Where the object on which the force is desired is displaced by a small amount ∆ s in thedirection of the unknown force. W is calculated for both positions and the force is then

computed using (7.50). This method is referred to in NISA/EMAG as the displacement method.

Another way to approximate equation (7.50) in finite element is the local Jacobian derivative ofthe integral energy form versus the displacement parameter. For instance, in electrostaticanalysis, the stored electric energy is obtained using

)48.7(.......2µ σ ω

δ =

)49.7(......s

W F

∂∂

=

)50.7(......)()(

s

sW ssW F

∆−∆+

=

)51.7(.......2

∫ Ω

Ω= d E W e ε

8/12/2019 emagtm



7-13

The electrostatic force can then be calculated using

This method is referred to in NISA/EMAG as the volume integration method.

The magnetic forces in nonlinear magnetostatic problems are more accurately computed with theaid of the stored coenergy, i.e. ,

Where Wc is the stored coenergy and s is the displacement parameter of the moving object.

In addition, NISA/EMAG computes the Lorentz forces in the current carrying regions using

Where, J is the current density, B is the magnetic flux density and ΩJ is the volume of thecurrent carrying region

Torque calculations

Similar to force calculations, torque calculations in electric motors, generators and other rotatingdevices are carried out using the virtual work principle, i.e. ,

Where Wc is the stored coenergy in the device and θ is the angular displacements of the

rotating object in radians. Both the displacement method and the volume integration method areused for the torque calculations in NISA/EMAG.

Coupled Magneto-Thermal Analysis

The presence of currents in electromagnetic devices (conduction currents, eddy currents)

)52.7(.......2

∫ Ω

∂

∂= d E

s

F e ε

)53.7(......s

W F c

h ∂∂

=

)54.7(.......∫ Ω

Ω×= J

d B J F !!!

)55.7(........θ ∂

∂= cW

T

8/12/2019 emagtm



7-14

produce power losses in the form of heat dissipation which alter the temperature

distribution in the device. This change in temperature can affect the device parameters,

thereby changing the performance of the device. Here, the calculation of the temperature

distribution in electromagnetic devices is given.

Once the current density is obtained from the electromagnetic analysis, the loss density Qin the device is calculated using

Where J is the current density and σ is the electric conductivity. For the steady current

flow analysis, J is the conduction current density. Whereas, for the magnetodynamic

analysis, the time averaged loss density is calculated by using:

Where J is the complex value of the current density and J * is the complex conjugate of J.

The temperature distribution T is then computed using the heat transfer equation

Where k is the thermal conductivity, λ = ρ C p, where ρ is the mass density and C p is the

specific heat. Q is the heat generation per unit volume obtained from (7.56) or (7.57). For

more details on heat transfer analysis, the user is referred to the NISA/HEAT User’s

Manual.

Temperature Dependent Material Properties

The electromagnetic properties of materials are actually temperature dependent. The

coupled HEAT-ELECTROMAGNETIC analysis are carried out using Iterative

schemes.

The material properties that are temperature dependent are:

)56.7(.......2

σ

J Q =

)57.7(.......*

σ

J J Q

•=

)58.7(......Q

t

T T k =

∂

∂+∇•∇− λ

8/12/2019 emagtm



7-15

1. Permittivity2. Permeability (Reluctivity)3. Conductivity

The variation of these properties with respect to temperature can be given in two ways:

1. Polynomial function2. Tabular Form

Infinite Element

The correct solution of an electromagnetic problem is obtained when the governingequation is solved along with the specified boundary conditions. Most of the real lifeelectromagnetic problems possess open geometry in full or part of their problem domain.This is because some of the boundary conditions are specified only at the boundary of theunbounded domain and these regions have therefore to be considered. Some example ofthese boundary conditions are the electrostatic potential φ and components of themagnetic vector potential A. In all these cases, value of this boundary condition is zero, because the electromagnetic fields at a point in the unbounded region varies roughly asthe reciprocal of the distance between that point and the electromagnetic sources presentin the problem. When the distance becomes large the fields tend to zero. If the problem isconsidered theoretically the field value at the open boundary is exactly zero, since thedistance is infinitely large. When the finite element method is used to solve the problem,one has to truncate the open boundary to achieve a practical problem region that can bemodeled. The truncation has to be judiciously decided.

The reduction of the modeling effort and the computation time can be considerable wheninfinite elements are used. At all portions of the open boundary infinite elements are placed. The shape function of these elements is chosen in such a way that the fields decayalong the outward direction of the open boundary. By a proper selection of the decay parameters, it is possible to reasonably match the field decay with that actually present inthe original problem. Alternatively, the usual shape function of the finite elements can beretained in the infinite element, but the portion of the infinite element lying on the open boundary can be made to approach infinity.

NISA/EMAG both the approaches for the infinite element have been used.

Infinite elements have been implemented for all analysis and sub-analysis types.

The classes of elements available are : 1. Element with Exponential Decay of potential 2. Element with Reciprocal decay of potential 3. Element with geometry mapped to infinity

8/12/2019 emagtm



7-16

The type of elements available are :

1. For Two-dimensional problems with NKTP = 101 and 102

and NORDR = 1 and 2

2. For Axisymmetric problems with NKTP = 103

and NORDR = 1 and 2

3. For Three-dimensional problems with NKTP = 104 and 105

and NORDR = 1 and 2

EMAG CAPABILITIES

Electric Field Analysis ( EFIELD )

Electric field analysis in electromagnetic devices induced by :a. Static charge distribution or static voltage distribution - ESTAT b. Steady state flow of electric charges or DC current - SCFL

Electrostatics ( ESTAT )

Electric field calculations in dielectric materials due to specified :1. Static electric charges2. Voltage distribution

Inputs :

- Specified static electric charges or voltage distribution or both

Outputs :- Electrostatic potential distribution- Electric field intensity distribution- Electric flux density distribution- Stored electric energy for each element- Total stored electric energy- Capacitance

Post processing is available for the potential, electric field intensity and the electric

flux density

Typical Problems:1. Capacitors2. Electrostatic precipitator3. Transmission lines4. Multi-conductor distribution with specified voltages5. Transformers and wall bushings

8/12/2019 emagtm



7-17

6. Outdoor insulators7. Supporting insulator blocks8. Design of corona shields9. Dielectric breakdown in High Voltage Engineering problems

Steady state current flow ( SCFL )

Electric field calculations in conducting materials due to specified:1. Steady flow of electric charges or DC current2. Voltage distribution

Inputs:- Specified steady flow of electric charges ( DC current ) or voltage distribution

or both

Outputs:

- Electrostatic potential distribution- Electric field intensity distribution- Current density distribution- Dissipated power for each element- Total dissipated power- Conductance

Post processing is available for the potential, electric field intensity and the currentdensity

Typical Problems:1. Particle counter in Tomography2. Particle detection in Bio-Medical Engineering3. Resistance of arbitrary shaped conductors

Magnetic Field Analysis ( MFIELD )

Magnetic field analysis in electromagnetic devices with direct current ( dc ) sources or time

varying current sources ( alternating ( ac ) or transient ). The magnetic material can be linear,

saturable ( nonlinear ) and / or permanent magnet

Magnetostatics

Magnetic field calculations in magnetic materials due to specified :1. Direct current ( dc ) excitation2. Permanent magnet

8/12/2019 emagtm



7-18

Types:1. 2 D planar and Axisymmetric Magnetostatic analysis using the magnetic vector

potential approach ( MGSV ).2. 3 D Magnetostatic analysis using the reduced scalar potential approach (MGSS)3. 3 D Magnetostatic analysis using the magnetic vector potential approach

( MGVP )Inputs:Specified direct current ( dc ) or permanent magnets or both

Outputs :- Magnetic vector potential or scalar potential distribution- Magnetic Flux density distribution- Magnetic field distribution- Stored magnetic energy and coenergy for each element- Magnetic force or torque ( when applicable )- Total stored magnetic energy and coenergy

- Inductance

Post processing is available for the magnetic vector potential or magnetic scalar potential,magnetic field intensity and the magnetic flux density.

Typical Problems:1. Solenoids2. Transmission lines3. Transformers4. D C Machines5. Circuit breakers6. Relays, Etc.

Magnetodynamics ( MGDN )

Magnetic field calculations in magnetic and conducting materials due to specified:Sinusoidal current ( ac ) excitation

Inputs:Specified Sinusoidal current ( ac )

Outputs:- Magnetic vector potential distribution- Magnetic Flux density distribution- Magnetic field distribution- Eddy current density distribution- Total current density distribution- Electric field distribution due to Eddy currents

8/12/2019 emagtm



7-19

- Total Electric field distribution- Power loss density distribution- Stored magnetic energy density for each element- Total stored magnetic energy- Total power loss

- Inductance- Resistance

Post processing is available for the magnetic vector potential, magnetic field intensity,magnetic flux density, eddy current density, total current density and instantaneous (orsnapshots ) time results

Typical Problems:1. Solenoids2. Transmission lines and bus bars3. Transformers

4. Induction Machines5. Synchronous Machines

Transient Magnetic Field Analysis ( TMAG )

Magnetic field calculations in magnetic and conducting materials due to specifiednon-Sinusoidal current ( ac ) excitation

Inputs:Specified arbitrary current excitation

Outputs :- Magnetic vector potential distribution- Magnetic Flux density distribution- Magnetic field distribution- Induced Eddy current density distribution- Electric field distribution due to Eddy currents- Power loss density distribution- Stored magnetic energy and coenergy for each element- Total stored magnetic energy and coenergy

Post processing is available for the magnetic vector potential , magnetic field intensity ,magnetic flux density at different time steps

Typical Problems:1. Solenoids2. Induction furnace3. Transformers4. Induction Machines5. Synchronous Machines

8/12/2019 emagtm



7-20

Coupled EMAG - HEAT Analysis

Coupled Heat transfer analysis in electromagnetic devices due to the power losscaused by the applied and induced currents. This analysis can be carried out coupling

heat with steady state current flow analysis, magnetostatics, transient magnetic fieldanalysis and magnetodynamic analysis. You can define the material properties asfunction of temperature.

Outputs:- Thermal and electric/magnetic field distributions.

Typical Problems:1. Solenoids2. Transformers3. Induction furnace

4. Electric furnace5. Induction Machines6. Synchronous Machines

Other Important Capabilities

Infinite elements:

a. Are available for all Analysis types. b. Three types of infinite elements are available :

1. Exponential Decay type2. Reciprocal Decay type3. Mapped element type

c. Infinite elements are available for :1. NKTP = 101, 102, 103, 104 and 105 and

NORDR = 1 and 2

Temperature Function:

Material properties can be defined as functions of temperature for CoupledHEAT analysis.

Tetrahedral Elements:

Tetrahedral elements are now available for 3 D analysis.

8/12/2019 emagtm



7-21

ELEMENT LIBRARY

A comprehensive library of finite and infinite elements is available in NISA/EMAG. Eachelement in library is identified by two variables, NKTP and NORDR. The variable NKTPspecifies the element types where as the variable NORDR specifies the element shape and no of

nodes.

Finite Elements

Element

(NKTP)

Element Description No. of

Nodes

DOF Analysis Types

101 Shell Element 3 to 8 1 EFIELD, MFIELD102 2-D Element 3 to 8 1 EFIELD, MFIELD103 Axisymmetric Element 3 to 8 1 EFIELD, MFIELD104 3-D Element 8 to 20 1, 3 Except TMAG, MGDN

105 Thick Shell element 8 to 20 1, 3 Except TMAG, MGDN120 Tetrahedral Element 4 1, 3 Except TMAG, MGDN

Infinite Elements

Element

(NKTP)

Element Description No. of

Nodes

DOF Analysis Types

101 Shell Element 4, 8 1 EFIELD, MFIELD102 2-D Element 4, 8 1 EFIELD, MFIELD

103 Axisymmetric Element 4, 8 1 EFIELD, MFIELD104 3-D Element 8 , 20 1, 3 Except TMAG, MGDN105 Thick Shell element 8, 20 1, 3 Except TMAG, MGDN

The input data for typical NISA/EMAG analysis type consists of three data blocks and a dataterminator.

- Executive commands data block- Model data block

- Analysis data block- Data terminator

Executive commands

The executive command data block is the first data block in a typical NISA input deck. Itconsists of command cards, which specify general control parameters for the execution of the program, such as: type of analysis, restart option, post-processing files, etc.

8/12/2019 emagtm



7-22

These are the list of executive commands used in NISA/3D-EMAG.

ANALYSIS Specifies analysis typeBLANK Specifies Blank common storage limit

CHEAT Specifies Coupled Magneto-Thermal analysisELEMENT ECHO Echoes element inputEXECUTION Selects execution / checking runFILE NAME Specifies NISA file prefixINITIAL POTENTIAL Defines initial potential for the whole problemNODE ECHO Echoes node inputORTHOTROPIC Specifies Orthotropic direction definitionRESEQUENCE Specifies Element resequencingSAVEFILE Saves specific NISA fileSTEP Total number of steps for transient magnetic field

Analysis

SUBA NALYSIS Specifies Sub-analysis typeWARNING Sets warning flag

- Acceptable minimum abbreviations are in bold face

Model Data

The model data block describes the model characteristics of the problem domain, e.g.,coordinates, connectivitiy, material properties, etc. It consists a *TITLE card, followed bydistinct data groups that are arranged arbitrarily to form the block.

These are list of Model Data used in NISA/EMAG.

*TITLE Problem title*ELTYPE Element type selection*ELEMENTS Element definition*RCTABLE Real constant table*LCSTSTEM Local coordinate system*NODES Nodal coordinates*MATDIR1 Orthotropic material axes at nodes*MATDIR2 Orthotropic material axes at elements

*MATEMAG Material property data*SETS Definition of a set of numbers (e.g., for *PRINTCNTL)*BHTAB Magnetic saturation curves ( BH tables )*TEMPFN Definition of temperature amplitude curve*TIMEAMP Definition of time amplitude curve


8/12/2019 emagtm



7-23

Analysis Control Data

The analysis data block describes data pertinent to boundary conditions. Print controls andspecific output features are also described in the analysis data. Specified zero and non-zero boundary conditions are considered as applied boundary conditions for a particular degree of

freedom and they are defined in the analysis data block.

*EMAGCNTL EMAG analysis control*TIMEINTEG Time integration parameters*STEPSIZE User specified time steps*MGDNPARM Magnetodynamic analysis parameters*INIFPOT Initial field potential for transient analysis*SPFPOT Voltage or magnetic scalar or vector potential*EFLUX Electric flux density*MFLUX Magnetic flux density

*CHRDEN Charge density*CURDEN Current density*CURSYM Current density symmetry*PMAG NET Permanent magnet coercive field strength*INFELE Specifies infinite element*FPOTHISTORY Field potential history*FPOTOUT Time steps for transient magnetic field output*FORCE Force data*TORQUE Torque data


Data Terminator

The input data signals the end of the data deck. The *ENDDATA group identification card

represents the data deck terminator which must be the last card in the input data deck.

*ENDDATA Input data terminator

The next section will give some useful hints to be taken care while modeling and doing analysis.It will also show the user step by step procedure to solve various types of problem encounteredin Electromagnetic analysis at low frequency. This section also includes some example problems showing the various capabilities of NISA/EMAG module.

8/12/2019 emagtm



7-24

HINTS FOR USING NISA/EMAG

This chapter gives useful hints for running NISA/EMAG. Both modeling and analysis hints arediscussed in this chapter. Modeling hints give information that an EMAG user should knowabout DISPLAY III. The analysis hints cover the NISA/EMAG module itself. The analyses are

categorized based on type of analysis such as electrostatic analysis, steady current flow,magnetostatic etc.

MODELING HINTS

Your Electromagnetic Problem

The basic steps to be followed for solving your electromagnetic problem:

Use the steps below to solve your problem.

1. Define your electromagnetic problem.

2. Identify your problem region in two or three dimension space. If part of your problem possesses open geometry, then you have to choose the problem space depending onwhether you are using infinite elements or not.

a. If you are using all finite elements : Choose sufficiently large space for the problem sothat some of fields or their derivatives decay to zero or negligible at the problem boundary. These fields will depend on the type of problem. b. If you using infinite elements on the open boundary: Choose sufficient space so that

the open problem region is roughly 3-10 times the dimesions of the electromagneticsources.

3. Define the various materials in the problem and their material properties.

4. Identify which of the fields or their derivatives tend to zero at the problem boundary.

a. If you are using all finite elements: Put these boundary conditions on the finiteelements

b. If you using infinite elements on the open boundary: Identify the faces of theinfinite elements that tend to infinity.

Also identify all other boundary conditions in the problem. e.g. currents in coppercoils, charge on a capacitor plate etc. Define the correct locations of these boundaryconditions.

5. Identify the analysis type which will depend on the governing equation.

6. Choose any one but only one self-consistent system of units for all the quantities. e.g.MKS units

8/12/2019 emagtm



7-25

7. Solve this governing equation subject to the defined material properties and boundaryconditions. The solution will yield the value of the fields mentioned in 4. Use thissolution to compute all other required quantities.

The basic steps to be followed for solving your electromagnetic problems by Finite Element

method :Use the steps below to solve your problem.1. Define your electromagnetic problem.2. Identify your problem region in two or three dimensional space. Choose sufficient

space as explained above.3. Define the various materials in the problem and their material properties.4. Identify all the boundary conditions as explained above.5. Identify the analysis type which will depend on the governing equation.6. Choose any one but only one self-consistent system of units for all the quantities. e.g.

MKS units.7. Subdivide the problem region into finite elements. During subdivision please note that

you have to put more number of elements in subregions where the spatial field variationis large and vice versa. Also the higher the number of elements you use the better theaccuracy you get. While subdivision you have to note that no element should definemore than one material, that is, the element face will always lie on the interface of twoor more materials. Thus the elements demarcate different materials. The creation ofelements automatically entails the creation of nodes depending on what type of elementyou are using. Defining the nodes means specifying the spatial position of all the nodesin the chosen coordinate system. Next define proper connectivity between the nodesand elements. Then your finite element mesh is fully defined.

8. Define the material properties of all the materials in the problem, that is, define theirnumerical values in the system of units you have chosen. Put these values for all theelements depending on what material they define.

9. Put the value of the relevant potentials equal to zero at the problem boundarydepending on how the problem is defined. Put these values on the boundary nodes or onthe face of the element that lies on the boundary. Again this will depend on the type offield mentioned above. For electric field analysis, the unspecified boundary willassume a homogeneous Neumann boundary, where, no flux/current can cross this boundary and for magnetic field analysis, any unspecified boundary will assume thetangential magnetic field along the boundary to be zero.

10. Put all the remaining boundary conditions at the correct spatial locations. Put thesevalues on the nodes or on the face of the element or on the whole element that definethe correct location for the boundary conditions. Again this will depend on the type of boundary condition defined above.

11. Define the analysis type identified earlier and solve the problem using the correct FiniteElement solver. The solution will yield the value of the fields mentioned in 4. Use thissolution to compute all other required quantities.

12. For more details on the Finite Element method, please consult any basic book on the

Finite Element method .

8/12/2019 emagtm



7-26

DISPLAY III : Post-Processing for EMAG

After you have run your EMAG solver two files are created :1. A post file > *26.dat as given above.2. A OUT file > *.out. The * corresponds to the filename you had given to your NIS

file by default or to some other name you had specified. This is an ASCII filewhich contains all your input finite element data and all results from EMAGsolver. You can edit this file for more processing or simply to get a hard copy.Read the post file in DISPLAY.

In the main menu you will see POST RESULTS. Select this. You will see the sub-menus. Theyare explained below:

1. CONTOURS : This menu is used to plot your EMAG results on the screen ascontours. Select this and you see the following sub-menus:

a. PICK RESULTS : This is to select a particular quantity from a list of quantities

that was produced as an output by the EMAG solver. b. CONTOUR STATUS : This is to set contour plotting parameters.

2. GRAPHS : This menu is used to plot your EMAG results in graphical form on thescreen or record them in files.

3. MISCELLANEOUS : In this menu select EMAG ARROW PLOTS. Then select therequired quantity to see it in the field plotting mode with directions of thefields shown by arrows.

HINTS REGARDING ELECTROMAGNETIC PROBLEM

The theoretical aspects of electromagnetic problems at low frequency are given at the beginning of this chapter. The practical approach for solving these problems is given below.

Electrostatic fields :

Electrostatic analysis :

In this the solution is found for the electrostatic scalar potential at the nodal locations in the problem region you have defined. It is important to note that you have to choose your

problem region properly as explained below.

i. Decide whether your problem is 2 or 3 dimensional. If the potential variation in onedirection is negligible or you are not interested in the potential variation in one particular direction then you can solve your problem in 2 D. If this does not hold thensolve your problem in 3 D. Also if your problem is axisymmetric the solve your problem in 2 D such that your 2 D coincides with the any plane passing through the tryaxis of symmetry.

8/12/2019 emagtm



7-27

ii. Choose your problem region in 2 or 3 D space large enough such that the potentialvalue at the boundary of the problem is negligible or tends to zero as compared to itsmaximum value in the problem ( say 0.1 to 1 % ). There will be two cases:a. If you are using finite elements only: A simple thumb rule is that you locate the

boundary at about 5 to 50 times the maximum dimension of your source region. As

you get experience you will be able to apply your judgement. b. If you using infinite elements on the open boundary: Choose sufficient space so thatthe open problem region is roughly 3-10 times the dimension of the electromagneticsources.

iii. Identify whether there is any symmetry in the problem, that is, the lines which are perpendicular to the equipotential lines (which are the lines of symmetry). If these linesare regular and can be identified easily you can use the concept of symmetry, otherwisedon't use this concept. The Electric field is parallel to these lines and hence the normal

electric field or the derivative of the potential normal to these lines is zero.

After you have defined your problem region adequately, use the following steps:

1. Define the complete geometry you will use for your finite element model generationincluding the problem regions as defined above. As far as possible choose the exactgeometry of the actual problem. In some cases the geometry may be quite involved andconverting some of the geometry to simple shapes may not affect the solution: you canthen choose the simplified geometry. If the solution gets affected than do not go forsimplification and choose the actual geometry. Identify clearly all the materials thatdefine the geometry.

2. Use DISPLAY III to define your geometry using grids (points), lines, curves and primitive geometry entities if possible. Next you use them to create patches for 2 D andhyperpatches for 3 D problems. Note that the patches ( for 2 D ) or hyperpatches (

for 3 D ) should cover your entire geometry without overlapping. The only

exception to this is the portion where you want to create finite elements from

nodes. These patches or hyperpatches are a must for creating the finite element

mesh.3. In DISPLAY III use the patches or hyperpatches to create the finite elements. Assign

each element to the proper material. These elements should cover the entire geometrywithout any overlap. All adjacent elements should be connected to each other. For this

use

NODES -> NODE MANAGEMENT - > NODE MERGE.

To verify whether you have done this correctly use

VIEW -> DISPLAY -> BOUNDARY -> ALL ELEMENTS.

The display should show white lines only at the problem boundary. Any

intermediate white lines show that the conditions given above do not hold and you

have to check for the same.4. Enter your material properties, that is, the value of permittivity of the material. Use FE

MODEL DATA. For isotropic material enter the permittivity in EXX only and keepingEYY and EZZ blank. For anisotropic case enter the proper values in EXX, EYY andEZZ.

5. Enter the boundary conditions:

8/12/2019 emagtm



7-28

a. Identify all the portions of the problem boundary where the potential tends to zero.Use FE BOUNDARY CONDITIONS -> EMAG -> SFPPOT

to put the potential = 0 at those boundary nodes. b. At the remaining portion of the boundary the normal derivative of the potential is zero

or is specified ( see c.3 below). ∂φ/∂n = 0 is a natural boundary condition for the

finite element analysis. Hence you should not specify any boundary conditionfor nodes on these portions.

c. Identify all the other given boundary conditions in the problem viz : boundaryconditions due to sources. These will be in 3 forms;

1. The electrostatic potential is given -> use SFPPOT

2. The charge density is given -> use CHRDEN

3. The normal electric field is given at some portion of the problem boundary -> useEFLUX

6. Use NISA FORMS to define the analysis type, analysis data, the ouput file names andany print controls. For analysis type use EFIELD and SUBA = ESTAT.

7. Finally save your database, nisa and session files.

8. Run your nisa file in EMAG and get the solution.9. Use DISPLAY III to see the output POST files or an ordinary ASCII editor to see theOUT file.

10. The force or torque on a moving object can be computed by using FORCE orTORQUE option in NISA FORMS -> NISA DATA GROUP -> MFIELD.

Steady state current flow:

All the information given above applies except for the following differences:

1. The normal derivative of potential or the normal electric field will not be specified but

the normal current density is specified. Hence use the EFLUX option to enter thevalue of normal current density only. Note the current can be DC only.2. There will not be any charge density. Hence do not use the CHRDEN option.3. You can use Coupled Thermal analysis to obtain the temperature distribution.4. For analysis type use EFIELD and SUBA = SCFL.

Magnetostatic fields :

Magnetostatic analysis using magnetostatic vector potential A: In this the solution is found forthe magnetostatic vector potential at the nodal locations in the problem region you have defined.All the information given above applies except for the following differences:

1. Use magnetostatic vector potential A instead of electrostatic potential φ. 2. Use magnetic field intensity H instead of electric field E . 3. Use magnetic flux density B instead of electric flux density D. 4. Since ∇ × A = B, when the normal derivative of A is zero then B is perpendicular to

the line of symmetry. When normal derivative of A is not zero then the tangentialcomponent of B is specified at the boundary. For the other case use MFLUX to specifythe tangential component of B.

8/12/2019 emagtm



7-29

5. Enter your material properties, that is, the value of permeability of the material. Use FE

MODEL DATA.a. For isotropic material enter the permeability in MUXX only and keeping MUYY and

MUZZ blank. For anisotropic case enter the proper values in MUXX, MUYY andMUZZ. Note : you have to enter the reciprocal of permeabilty.

b. For ferromagnetic materials use MUXX for entering any dummy value. Then click tothe right of MUXX and enter the B-H curve identification number. Next in NISA FORMS -> NISA DATA GROUP -> MFIELD click B-Htable and enter the H and B values.

c. For permanent magnets if the B-H table is specified then you have to find the value ofmagnetic coercivity from the B-H curve. This is the value of H at the point where thecurve cuts the B = 0 axis. You have to choose the absolute value of H. Then you shiftthe B-H curve to the right by the value of coercivity found above. Enter the B-H tableas in b. above. If B-H curve is not specified then you should know the value ofmagnetic coercivity. To enter the value of magnetic coercivity use PMAGNET option and specify Hcx, Hcy and Hcz in x , y and z directions. You have to specify

this for both the cases.

6. Enter the boundary conditions:a. Identify all the portions of the problem boundary where the magnetic potential tends to

zero. Use FE BOUNDARY CONDITIONS -> EMAG -> SFPPOT to put the potential = 0 at those boundary nodes, that is, Ax = Ay = Az = 0.

b. At the remaining portion of the boundary the tangential magnetic field zero or isspecified ( see c.3 below). This is a natural boundary condition for the finite elementanalysis. Hence you should not specify any boundary condition for nodes on

these portions.c. Identify all the other given boundary conditions in the problem viz : boundary

conditions due to sources. These will be in 4 forms ;1. The magnetostatic potential is given -> use SFPPOT

2. The current density is given -> use CURDEN

3. The tangential magnetic flux density is given at some portion of the problem boundary -> use MFLUX (for 2 D only)

3. The magnetic coercivity is given. Use the PMAGNET option as givenabove.

8. For analysis type use MFIELD andSUBA = MGSV for 2 D problems.

and SUBA = MGVP for 3 D problems.For problems with B-H curve (nonlinear) you have to specify the number of iterations,relaxation parameter etc. in NISA FORMS -> NISA DATA GROUP -> MFIELD.Then use the EMAGCNTRL option


8/12/2019 emagtm



7-30

Magnetostatic analysis using magnetostatic scalar potential φφφφ :

In this the solution is found for the magnetostatic scalar potential at the nodal locations in the problem region you have defined. All the information given above applies except for thefollowing differences:

1. Use magnetostatic scalar potential φm instead of magnetostatic potential A. 2. Since H = −−−− ∇ φ m , when the normal derivative of φ is zero then B is parallel to the

line of symmetry. When normal derivative of φm is not zero then the normalcomponent of B is specified at the boundary. For the case of ∂φ/∂n = 0 you need not putany boundary condition. For the other case the MFLUX option is not available.

3. For analysis type use MFIELD and SUBA = MGSS for 3 D problems only.For problems with B-H curve (nonlinear) you have to specify the number of

iterations, relaxation parameter etc. inNISA FORMS -> NISA DATA GROUP -> MFIELD. Then use the

EMAGCNTRL option


Magnetodynamic fields :

Magnetodynamic analysis for sinusoidal time varying currents or magnetic

fields using vector potential A :

In this the solution is found for the vector potential at the nodal locations in the problem region.At present the analysis is available in 2 D only and only the z or θ component of A is obtained.

All the information given above applies except for the following differences:

1. In CURDEN you have to specify the frequency and phase of the current2. You can change the value of frequency using MGDNPARM where you can specify

frequency, the output type ( polar or real/imaginery form ) and the chosen conductor.3. For analysis type use MFIELD and SUBA = MGDN for 2 D problems only.4. The solutions can be viewed at different electrical angles ( 0 to 360 degrees ). For this use

FPOTOUT in NISA FORMS -> NISA DATA GROUP -> MFIELD.

5. Permanent magnet capability is not applicable.

8/12/2019 emagtm



7-31

Transient Magnetic analysis for arbitrary time varying currents or magnet fields

using vector potential A :

In this the solution is found for the vector potential at the nodal locations in the problem regionyou have defined. At present this analysis is available in 2 D only and therefore, only the z or θ

component of A canl be obtained. All the information given above applies except for thefollowing differences:

1. Permanent magnet capability is available.2. In CURDEN you have to specify the TIME AMPLITUDE identification number. Then

choose NISA FORMS -> NISA DATA GROUP -> MFIELD. Enter the values ofcurrent for various time instants in the TIME AMPLITUDE option.

3. You have to enter the time integration data parameters inNISA FORMS -> NISA DATA GROUP -> MFIELD. Then choose the optionTIMEINTEG or STEPSIZE.

4. The solutions can be viewed at different time instants. For this use FPOTOUT

NISA FORMS -> NISA DATA GROUP -> MFIELD.5. The force or torque on a moving object can be computed by using FORCE or TORQUE

option in NISA FORMS -> NISA DATA GROUP -> MFIELD.

6. For analysis type use MFIELD and SUBA = TMAG for 2 D problems only.

Coupled Electromagneto-Thermal analysis :

In this you can do a heat transfer analysis in electromagnetic devices due to the power losses produced by the presence of currents. This analysis can be carried out coupled with :

a. EFIELD -> SCFL b. MFIELD -> MGSV

-> MGVP

-> MGSS

-> MGDN

-> TMAG

For more details about the use of heat transfer analysis please refer to the HEAT Manual.For using HEAT analysis coupled with EMAG please note the following:

1. First model the EMAG problem and create the corresponding NISA file. In this NISAfile you add :

a. CHEAT = ON after SUBA = .... b. Put SAVE = 20,26 instead of SAVE = 26.

2. Use the same model and remove all the material properties and boundary conditions.Then add the material properties and boundary conditions for HEAT analysis. Changethe analysis type from EMAG to HEAT and also add all the required analysis parameters print controls etc. Create the corresponding NISA file. In this NISA file youadd: read, EMAGNISfilename20.dat after the boundary conditions.

8/12/2019 emagtm



7-32

3. For static analysis type use SHEAT4. For transient analysis type use THEAT5. Solutions are obtained for the temperature distribution only.

8/12/2019 emagtm


NISA/ EMAG Training Manual MODELING Session 1

8-1

CHAPTER 8

MODELING SESSION 1

A simple modeling session will be presented in this chapter. You will use the menu mode(mouse driven) to communicate with the program. This mode is easy to operate and requires noknowledge of the DISPLAY command syntax.

Although the menu mode is user friendly, describing the steps to be followed for such amodeling assignment is an enormous task. In this text, menu selections are described as a chainof commands and follow a set of conventions. It is very important to get used to theseconventions before attempting these sample sessions. The conventions adhered to are as follows :

a) Bold capital entries in shaded boxes are selections from the top level menu. b) Underlined entries in shaded boxes sre selections from the sublevel menu.

c) Ordinary capital in shaded boxes are selections from the operation menu (tokens).d) Italic capital entries in shaded double boxes are selections from the hot button menu.e) The symbol ‘→’ means clicking the left button of the mouse.f) The symbol ‘←’ means clicking the right button of the mouse.g) Entries in non shaded boxes mean inserting data from the keyboard or the numeric pad.h) The symbol <CR> is used to describe a carriage return.

Also, remember that the left mouse button (→) is used for accepting a certain operation and to proceed to the next level of operations. Clicking the right button of the mouse is generally doneat the end of one complete set of instructions to get out of that chain. Almost all the stepsdescribed in this tutorial, thus, end with the symbol ‘←’ to instruct that the right button of the

mouse be clicked to end that set of instructions. Please keep an eye open for these symbols. Thecomplete chain of menu instructions for a certain task is kept within border lines to identifythem.

If you commit an error during the modeling session, you may use the “UNDO’ hot button toundo the last command. ‘ESC’ on the keyboard will abort the current operation.

The goal of this session is to model a nonlinear inductor, as shown in Figure 8.0. Due tosymmetry of the problem only a quarter of the inductor is modeled in the global XY plane. Thecoil is excited with 2000 A/m2. The material property (reluctivity) of copper and steel are definedas follows :

Material = IsotropicMUXX (steel) = BH table is used, see table (.8.1)MUXX (copper) = 7.957 x 10+5 Hm –1

Since the geometry of this inductor model is in the XY plane therefore 2D planar element ischosen. NISA offers one of the most complete element libraries among commercial softwares,and a list of currently available elements can be found in the User’s manual.

8/12/2019 emagtm


MODELING Session 1 NIISA/ EMAG Training Manual

8-2

The first step in modeling this problem is to create the geometry of the inductor cross-section interms of lines. Lines are created by joining grids (points in space with predefined coordinates).Once the geometry is obtained in terms of lines, automatic mesh generation is used and the meshis created. Then, excitation (i.e., current density) and boundary conditions along with material

and geometric properties are defined for the elements. Furthermore, analysis and sub analysistypes are defined at this stage. Finally, at the end of modeling a NISA ASCII file is obtained to perform a nonlinear magnetostatic analysis.

5 8 9

Core 0.24 6 7

Coils

• 1.0

0.2

1 2 3

1.0

Figure 8.0 A Quarter model of a nonlinear inductor

8/12/2019 emagtm



8-3

Step 1 Now create grid points for the given geometry. Enter the coordinate (0/0/0) usingkeyboard and hit <CR>. The user will see grid no. 1 appearing on the screen.Similarly, repeat this operation for the following grids, i.e. 2, 3, 4, 5, 6, 7, 8 and 9

respectively. See Figure (8.1),

Figure 8.1 Grid Generation

GEOM GRID CREATE XYZ COORDINATE XYZ DATA

Figure 8.1 Grid generation

8/12/2019 emagtm



8-4

Step 2 Now create lines by joining two grid points. Pick two grid points 1 and 2 using cursor.

User will see line no. 1 appearing on the screen. Repeat this Figure 8.2 is obtained.

User can skip this step and proceed directly to step 4 if user chooses to create patches by picking4 grid points.

GEOM LINE CREATE WORK PLANE 2 GRIDS

CURSOR PICK

Figure 8.2 Patch generation

8/12/2019 emagtm



8-5

Step 3 To generate a patch follow the command sequences given below. Pick two lines tocreate a patch or pick four grid points to create a patch. In this example step 3 is skipped, hencegrid method is chosen for patch creation.

Now pick grid points 1, 2, 4 and 6, respectively with cursor, user will see patch #1 appearing onscreen. Similarly, pick grid points, 2, 3, 6 and 7 for patch 2, grid points 6, 7, 9 and 8 for patch 3and finally pick grid points 4, 6, 9 and 5 to create patch #4.

Step 4 To generate finite element mesh choose the following command sequence. In this problem quadrilateral elements (element type 102) are chosen. Also E1/E2 are definedas 5/5, which means a patch will be descretized with 25 elements 5 in each direction,see Figure 8.3. User must be careful when descretizing different patches asconnectivity of the nodal points should always exist in the model.

Now pick patches 1, 2, 3 and 4, respectively, to create finite elements in the model, see Figure8.3.

GEOM PATCH CREATE LINE METHOD 2 LINES

CURSOR PICK

GEOM PATCH CREATE GRID METHOD 4 GRIDS

CURSOR PICK

FE GENRATION MESH FEG OPTION QUADRILATERAL E!/E2

CURSOR PICKINPUT PATCH

8/12/2019 emagtm



8-6

Once the finite element mesh is generated, user must delete all unreferenced nodes. Also usermust merge the inactive nodes. This is an important step, because if inactive nodes are present inthe FE model then the analysis results will not be correct.

Figure 8.3 Finite Elements

FE GENRATION MESH FEG OPTION QUADRILATERAL E!/E2

CURSOR PICKINPUT PATCH

8/12/2019 emagtm



8-7

Step 5 Now user must define the material properties. In this nonlinear inductor problem twomaterials exist, they are copper and steel. For steel BH curve is accounted, see Table8.1, for copper reluctivity = 7.957 x 10+5 Hm-1 is used.

In order to define reluctivity of each material follow the command syntax (1), see forms shownin Figure 8.4 and 8.5a respectively. User will define the material constants depending on theanalysis types. For the nonlinear material, the user should enter 1.0 in the first column of MUXXand click on the adjacent tile. The form in Figure 8.5a will appear. At this stage the user mustenter the BH curve number under IDCURV.

(1)

OR

(1)

NISA DATA GROUP NISA FORMS MATERIALMFIELD

FE GENERATION FE MODEL DATA MATERIAL DATA

ADD Emag

FE GENRATION NODES NODE MANAGEMENT DELETE INACTIVE

ALL

FE GENRATION NODES NODE MANAGEMENT MERGE NODES

ALL

8/12/2019 emagtm



8-8

Figure 8.4 Model data form

ADD Emag

8/12/2019 emagtm



8-9

For nonlinear steel follow the command and sequence (2) and enter the BH table data’s in theform shown in Figure 7.6. The BH table used here is also given in table 1.

(2)

NISA DATA GROUP NISA FORMS BH TABLE

ADD

MFIELD

ENTER BH TABLE

Figure 8.5a Material property form

Figure 8.5b BH Curve ID form

8/12/2019 emagtm



8-10

Table 8.1. BH Table

H B150.53 1.0154.41 1.025

158.33 1.05162.3 1.075166.33 1.1170.43 1.125174.65 1.25179.01 1.175183.55 1.2188.34 1.225

Figure 8.6 BH table form

8/12/2019 emagtm



8-11

193.46 1.25199.03 1.275205.2 1.3212.18 1.325220.27 1.35

229.87 1.375241.53 1.4256.03 1.425274.45 1.45298.32 1.475329.79 1.5371.87 1.525428.89 1.55506.97 1.575614.92 1.6765.39 1.625976.66 1.651275.2 1.6751699.7 1.72306.6 1.7253178.9 1.754439.0 1.7756268.2 1.88936.8 1.82512848.0 1.8518607.0 1.875

27128.0 1.939793.0 1.92558704.0 1.9587072.0 1.975129826.0 2.0

Step 6 Now user can define the boundary conditions for the nonlinear inductor model. TheDirichlet boundary condition is defined on the two sides of the steel core of theinductor, as shown in Figure 8.7.

FE GENERATION BOUNDARY CONDN. SPFPOTEMAG

BORDER

8/12/2019 emagtm



8-12

Step 7 At this stage user can define the excitation for the nonlinear inductor. In this examplecurrent density Jz = 2000 A/m2 is used in the elements as shown in Figure 8.8.

FE GENERATION BOUNDARY CONDN. CURDENEMAG

BORDER

Figure 8.7 Dirichlet boundary condition

8/12/2019 emagtm



8-13

Step 8 Finally, user must define the title, the EMAG control, and the executive command cardssuch as analysis type, and sub analysis type. The forms of which are shown in Figures8.9, 8.10 and 8.11 respectively. Follow the command sequences given below.

TITLE

EMAG CONTROL

Figure 8.8 Current density

NISA DATA GROUP NISA FORMS TITLEMFIELD

NISA DATA GROUP NISA FORMS EMAGCONTROL

MFIELD

8/12/2019 emagtm



8-14

ANALYSIS / SUB ANALYSIS TYPE

NISA DATA GROUP NISA FORMS SUBAMFIELD

Figure 8.9 Title form

8/12/2019 emagtm



8-15

Figure 8.10 EMAG control form

Figure 8.11 Sub analysis form

8/12/2019 emagtm



8-16

Step 9 The physical geometric properties are defined in this step. These properties aredependent on the type of element chosen. The nodal thicknesses are defined through entries inthe Element Property form shown in Figures 7.12 and 7.13

Step 10 After obtaining the finite element mesh of the problem, you have to check whether theelements are proper viz : warping, distortion, aspect ratio, connectivity etc. for thisfollow the menu sequence.

Step 11 Futhermore, user must write .NIS, .DBS and .NEU files. NISA input file will be usedfor running the EMAG analysis, whereas .DBS (binary file) and NEU (ASCII file)contains the geometry and the finite element information of the model. The files arewritten by the following the procedure given below

FE GENERATION →→→→ FE MODEL DATA →→→→ PROPERTY DATA →→→→

1) select ADD button in the ‘ELEMENT PROPERTIES’ form.

2) Select SHELL button in the ‘ELEMEMT TYPE’ form.

3) The form for inserting nodal thicknesses appears. Click the mouse button ‘→→→→’ tohighlight the box for Nodal Thickness 1. Insert the thickness value as 0.1.

4) Now click the box ‘ALL’ to repeat above thickness for all the nodes.

5) Click the ‘OK’ button to accept the defined values.

6) Now click the ‘QUIT’ button.

FILE MANAGEMENT →→→→ WRITE →→→→ NISA FILE →→→→ filename →→→→

FILE MANAGEMENT →→→→ WRITE →→→→ DATABASE FILE →→→→ filename →→→→

FILE MANAGEMENT →→→→ WRITE →→→→ NEUTRAL FILE →→→→ filename →→→→

You should enter the name of the file in which you want to store the above files.

FE GENERATION ELEMENTS. ELEMENT CHECKVERIFICATION

FE GENERATION ELEMENTS. NISA CHECKVERIFICATION

8/12/2019 emagtm



8-17

Figure 8.12 Property forms

Figure 8.13 Property forms

8/12/2019 emagtm



8-18

Step 12 Program has its own editor and you may view and edit the created NISA file. You areencouraged to view this file and understand the format of this file., which isthoroughly documented in the EMAG User’s manual.. In many cases, you may make

minor changes and add more information regarding data groups which are notsupported through DISPLAY III. Figure 8.14 illustrates the NISA file.

Step12 The modeling is now done and you can quit DISPLAY III now (as shown below)

FILE MANAGEMENT →→→→ EDIT →→→→ filename →→→→

The NISA input file will now appear on the screen. You may scroll the file by using thescrollbar at the right side of the screen. For now, do not attempt to make any changes inthe file. After viewing, exit the editor by clicking the mouse in the ‘QUIT’ box

Figure 8.14 NISA file

FILE MANAGEMENT→→→→ QUIT PROGRAM →→→→ (Y)

8/12/2019 emagtm



8-19

This completes modeling of the demonstration problem.

RUNNING EMAG CODE :

The next step is to run the analysis using EMAG. On workstations, user can type EMAG at prompt to run EMAG analysis. Whereas on PC choose option N in NISA386 menu OR executeEMAG through WINDOWS 95 if your version is WINDOWS based. Type the NISA input filename you had chosen earlier and hit <CR> to use the same file name as the output file.

POST PROCESSING : For viewing the results after a successful run of EMAG analysis followthe procedure below :

1)

2)

Now user will see the form which contains the output parameters to be post processed, seeFigure 8.15.

In this example we have chosen the Resultant Flux density (B) to be viewed. Figure 8.16 showsthe contour lines of the Magnetic Flux density distribution.

FILE MANAGEMENT READ POST FILES

POST RESULTS CONTOURS PICK RESULTS

8/12/2019 emagtm



8-20

Figure 8.15 Output Parameters

Figure 8.16 Magnetic Flux density distribution in a nonlinear inductor

8/12/2019 emagtm



9-1

CHAPTER 9

MODELING SESSION 2

Before going through this session, read the information given at the beginning of the Modelingsession 1. Current distribution in a steel plate with a square punchout hole at the centre isconsidered in this session. The problem geometry is shown in Figure 9.1 along with grid points.Two copper electrodes are connected at the two ends of the plate. A constant current density of J= 1.0 A/m2 is injected into the right electrode. The left electrode is maintained at a constant potential of 0 volts. You have to determine the current density and the temperature distributionin the steel plate.

The material property (conductivity) of copper, steel and air are defined as follows :

Material = Isotropic

SIXX (steel) = 1.0 x 10+6

mho/mSIXX (copper) = 5.8 x 10+7 mho/m

SIXX (air) = 1.0 x 10-15 mho/m

Since the geometry of this steel plate model spans the three dimensional space therefore 3Dhexahedral element is chosen. NISA offers one of the most complete element libraries amongcommercial softwares, and a list of currently available elements can be found in the User’smanual.

Square punchout hole at the centre of size 0.04 x 0.04 m16 9 14

7Steel Plate right

12 15 copperelectrode

left 8 10copper 0.08 melectrode 6 11

0.01 m 0.10 m3 4

0.02m1 2 2 5 13

Thickness of the plate is = 0.04 metres

( All dimensions in meteres)

Figure 9.0 Geometry of the steel plate with a square punchout hole at the center

8/12/2019 emagtm



9-2

The first step in modeling this problem is to create the problem geometry. The lines are created by joining grids (points in space with predefined coordinates). These lines are used to createsurfaces called patches. These surfaces are used to create volumes called hyperpatches in such a

way that the full model is spanned. Once the geometry is obtained in terms of hyperpatches,automatic mesh generation is used to create the 3D mesh. Then, excitation (i.e., current densityand applied voltage) and the boundary conditions along with material and geometric propertiesare defined for the elements. Furthermore, analysis and sub analysis types are defined at thisstage. Finally, at the end of modeling a NISA ASCII file is obtained to perform a steady statecurrent flow analysis.

Step 1 Now create grid points for the given geometry. Enter the coordinate (-0.06/-0.04/-0.02)using keyboard and hit <CR>. The user will see grid no. 1 appearing on the screen.Similarly, repeat this operation for the following grids, i.e. 2, through 16 respectively.The grids are marked in Figure (9.0). The grids appear as in Figure (9.1).



8/12/2019 emagtm



9-3

Step 2 Now create lines by joining two grid points. Pick two grid points 1 and 2 using cursor.User will see line no. 1 appearing on the screen. Repeat this Figure 9.2 is obtained.

Figure 9.2 Generation of lines

Step 3 To generate a patch follow these command sequences. Pick two lines to create a patch or pick four grid points to create a patch. In this example patches are created using twolines. This is shown in Figure 9.3. For example Patch #1 is created using line nos # 1and 2.

GEOM LINE CREATE WORK PLANE 2 GRIDS

CURSOR PICK


CURSOR PICK

8/12/2019 emagtm



9-4

Figure 9.3 Generation of patches

Step 4 Now hyperpatches can be created using a number of methods. Note that, in the previoussteps, grids, lines and patches were created in an XY plane at z = -0.02 m. To model thesteel plate hyperpatches should cover the area between the XY planes z = -0.02 and z =0.02 m., since the structure is uniform in the z direction. The different methods forcreating hyperpatches is given below:

a. Translate all the grids by an amount z = 0.04 m. Use the grids in the two XY planes to

create hyperpatches. b. Translate all the grids by an amount z = 0.04 m . Join these grids by lines : use the lines in

the two XY planes to create hyperpatches.c. Translate all the grids by an amount z = 0.04 m . Join these grids by lines. Use these lines

to create patches : use the patches in the two XY planes to create hyperpatches.d. Translate all the lines by an amount z = 0.04 m . Use these lines to create patches : use the

patches in the two XY planes to create hyperpatches.


CURSOR PICK

8/12/2019 emagtm



9-5

e. Translate all the lines by an amount z = 0.04 m . Use these lines in the two XY planes tocreate hyperpatches.

f. Translate all the patches by an amount z = 0.04 m. Use the patches in the two XY planesto create hyperpatches.

And there can be many other methods. In some cases you may not be required to generatehyperpatches at all, that is, when the problem is uniform in the z direction or when the problem isaxisymmetric. In this case, the problem is uniform in the z direction.

Step 5 To generate finite element mesh you can follow two methods

1. If you have created hyperpatches choose the following command sequence. In this problem hexahedral elements (element type 104) are chosen. If E1/E2/E3 are defined as5/5/5, it means a hyperpatch will be descretized with 625 elements 5 in each direction

2. If you have created patches only in the XY plane z = -0.02 m, then discretize the patchesfirst, choose the following command sequence (see Figure 9.3). User must be carefulwhen descretizing different patches as connectivity of the grid points should always existin the model.

Now pick patches 1 through 9 respectively, to create finite elements in the model, seeFigure 9.4.

FE GENRATION MESH FEG OPTION HEXAHEDAL E!/E2/E3

CURSOR PICKINPUT HYPERPATCH

FE GENRATION MESH FEG OPTION QUADRILATERAL

E1/E2 CURSOR PICKINPUT PATCH

8/12/2019 emagtm



9-6

Figure 9.4 Finite element generation on all patches using 2D elements of type 102 and order 1

Once the finite element mesh is generated for 2D elements (type 102 with order 1), choose thefollowing command sequence

Then in NORMAL-VECTOR choose the Z-AXIS. In DISTANCE put the value 0.04,which, isthe thickness of the steel plate. In NUM-OF-COPIES put 4 (say) for a layer of 4 elements in thez direction.

Next, you have to delete the 2D elements of type 102. Choose the following command sequence.

FE GENRATION ELEMENTS CONSTRUCTION

LINEAR SWEEP

FE GENRATION ELEMENTS CONSTRUCTION DELETE

MORE OPTIONS… ELEMENT TYPES

8/12/2019 emagtm



9-7

Enter 102 for the ELEMENT TYPES.

Step 6 Once the finite element mesh is generated, user must delete all unreferenced nodes. Alsouser must merge the inactive nodes. This is an important step, because if inactive nodesare present in the FE model then the analysis results will not be correct. The final result

is shown in Figure 9.5.

Figure 9.5 The finite element mesh with element type 104 and order 1


ALL


ALL

8/12/2019 emagtm



9-8

Step 7 Now user must define the material properties. In this steel plate problem three materialsexist, they are copper, steel and air. For steel conductivity = 1.0 x 10+6 mho/m,, forcopper conductivity = 5.8 x 10+7 mho/m and for air conductivity = 1.0 x 10-15 mho/m.

In order to define conductivity of each material follow the command syntax (1), see formsshown in Figure 9.6a and 9.6b respectively. User will define the material constants depending onthe analysis types. For the steel plate, copper electrode and air, the user should enter therespective values in the first column of SIXX .

(1)

OR

(1)

NISA DATA GROUP NISA FORMS MATERIALMFIELD

FE GENERATION FE MODEL DATA

ADD

MATERIAL DATA

ADD Emag

Emag

8/12/2019 emagtm



9-9

Figure 9.6a Model data form

Figure 9.6b Material property form

8/12/2019 emagtm


8/12/2019 emagtm



9-11

Now, the user should do the following : in SET-ID , the set id number should be entered 2 (say),in FACE-NUMBER the value 5 should be entered, in FLUX RATE the value 1.0 should beentered and in ELEMENT-IDS choose BOX CORNER and select the required elements. Theuser can find the face number 5 by the following command sequence

Now cursor pick an element on the right edge of the right copper electrode.

Figure 9.8 The injected current density on the right copper electrode

Step 10 Finally, user must define the title, the EMAG control, and the executive command cardssuch as analysis type, and sub analysis type. The forms of which are shown in Figures9.9, 9.10 and 9.11 respectively. Follow the command sequences given below.

FE GENERATION BOUNDARY CONDN. CURDENEMAG

ADD ON ELEMENTS

HOT FAC CURSOR PICK

8/12/2019 emagtm



9-12

TITLE

EMAG CONTROL



NISA DATA GROUP NISA FORMS TITLEEFIELD

NISA DATA GROUP NISA FORMS EMAG CONTROLEFIELD

NISA DATA GROUP NISA FORMS EXECUTIVE

SUBA

EFIELD

8/12/2019 emagtm



9-13


Figure 9.11 SUB analysis form

8/12/2019 emagtm



9-14

Step 11 After obtaining the finite element mesh of the problem, you have to check whether theelements are proper viz : warping, distortion, aspect ratio, connectivity etc. for thisfollow the menu sequence.

Step 12 Futhermore, user must write .NIS, .DBS and .NEU files. NISA input file will be usedfor running the EMAG analysis, whereas .DBS (binary file) and NEU (ASCII file)contains the geometry and the finite element information of the model. These files arewritten by the following the procedure given below

Step 13 The program has its own editor and you may view and edit the created NISA file. Youare encouraged to view this file and understand the format of this file, which isthoroughly documented in the EMAG User’s manual. In many cases, you may makeminor changes and add more information regarding data groups which are notsupported through DISPLAY III. Figure 9.12 illustrates the NISA file.



FILE MANAGEMENT →→→→ WRITE →→→→ NISA FILE→→→→ filename →→→→ FILE MANAGEMENT →→→→ WRITE →→→→ DATABASE FILE→→→→ filename →→→→

FILE MANAGEMENT →→→→ WRITE →→→→ NEUTRAL FILE→→→→ filename →→→→

You should enter the name of the file in which you want to store the above files

FE GENERATION ELEMENTS. ELEMENT CHECKVERIFICATION

FE GENERATION ELEMENTS. NISA CHECKVERIFICATION

8/12/2019 emagtm



9-15

Figure 9.12 Nisa file



RUNNING EMAG CODE :

The next step is to run the analysis using EMAG. On workstations, user can type EMAG atcommand prompt to run EMAG analysis. Whereas on PC choose option N in NISA386 menuOR execute EMAG through WINDOWS 95 if your version is WINDOWS based. Type the NISA input file name you had chosen earlier and hit <CR> to use the same file name as theoutput file.


FILE MANAGEMENT→→→→ QUIT PROGRAM →→→→ (Y)

8/12/2019 emagtm



9-16

1)

2)

Now user will see the form which contains the output parameters to be post processed, seeFigure 9.13.

Figure 9.13 Form for picking the Resultant current density

In this example we have chosen the Resultant Current density (J) to be viewed. Figure 9.14shows the contour lines of the Current density distribution.



8/12/2019 emagtm



9-17

Figure 9.14 The distribution of the Resultant current density

You can see the resultant current density field arrow plots using the following commandsequence. This is shown in Figure 9.15

POST RESULTS MISC. RESULTS EMAG ARROW PLOTS

CURRENT DENSITY

VIEW DISPLAY OPTIONS BOUNDARY LINE

ALL ELEMENTS

8/12/2019 emagtm



9-18

Figure 9.15 The arrow field plot for the Resultant current density

8/12/2019 emagtm



10-1

CHAPTER 10

MODELING SESSION 3

Before going through this session, read the information given at the beginning of the Modelingsession 1. The problem of a very long (can be considered infinite) parallel conducting plate ofnegligible thickness forming a capacitor is considered. The problem geometry is shown inFigure 10.0a. The voltage of the upper plate is assumed to be 100 volts and that of the lower plate to be –100 volts. You have to determine the electric field and the voltage distribution in themedium surrounding the two plates.

Upper conducting plate

100 volts

Lower conducting plate0.01 m

-100 volts

0.01The plates are very thin and are very long as shown by wavy lines

( All dimensions in meters )

Figure 10.0a Parallel plate capacitor

The material property (permittivity) of the air medium surrounding the two conducting plates isdefined as follows :

Material = Isotropic

EXX (air) = 8.85 x 10-12

F/m

The parallel conducting plates are very long in the direction perpendicular to this page. Hence,only a 2D model of the problem is necessary. This 2D model is taken in the XY plane. The platesare taken parallel to the X-axis and are centred with respect to the origin. Due to odd symmetryabout the X-axis, the potential φ on the X-axis is 0 volts. Due to even symmetry about the Y axisthe voltage φ is a mirror image of itself with respect to the Y axis. Hence, on the Y-axis theelectric field is tangential to it( i.e. x component is zero). Hence, only one fourth of the 2D

8/12/2019 emagtm



10-2

model is necessary for analysis; which is taken as the first quadrant. On the X axis, the voltage φ is set to 0 volts, on the Y axis the normal component of the gradient of the potential φ is 0volts/m and at the infinite radial distance in the first quadrant voltage φ tends to 0 volts. This isshown in Figure 10.0b.

Y

The potential φ = 0 on all the infinitePortions of the first quadrant

0.005 m

One half of upper plate0.005 m at potential φ = 100

XOn X Axis potential φ = 0

Figure 10.0b The portion in 2D required for analysis

Since the geometry of this capacitor model is in 2D, therefore quadrilateral element is chosen. NISA offers one of the most complete element libraries among commercial softwares, and a listof currently available elements can be found in the User’s manual.

The first step in modeling this problem is to create the geometry of one-fourth of the capacitorcross-section in terms of lines. The lines are created by joining grids (points in space with predefined coordinates). These lines are used to create surfaces called patches. Once thegeometry is obtained in terms of patches, automatic mesh generation facility is used and themesh is created. Then, excitation (i.e., applied voltage) and the boundary conditions along withmaterial properties are defined for the elements. Furthermore, analysis and sub analysis typesare defined at this stage. Finally, at the end of modeling a NISA file is obtained to perform an

Electrostatic analysis.

Step 1 It should be noted that all dimensions are in metres, that is, of the order of 0.01 metre orless. In DISPLAY III, the distance tolerance for plotting and other computations are set to 0.001 by default. For the present problem this tolerance will be high. Hence put new tolerance value of0.00001. This is can be done by using the following command sequence. For each case enter avalue 0.00001.

O n Y A x i s

∂ φ / ∂ n

= 0

8/12/2019 emagtm



10-3

AND

Step 2 Now create grid points for the modeled geometry. Enter the coordinate (0/0/0) usingkeyboard and hit <CR>. The user will see grid no. 1 appearing on the screen.Similarly, repeat this operation for the following grids, i.e. 2, 3 and 4 respectively. SeeFigure (10.1),


Step 3 Now create a circle with center (0/0/0) and radius = 0.1. Use the following commandsequence. Now click CENTRE and KEY IN XYZ DATA and enter 0/0/0/. Next, clickRADIUS and enter 0.01 and finally click EXECUTE (GO) and Figure 10.2 is obtained.


SET/SHOW TOLERANCE PICK TOLERANCE

SET/SHOW TOLERANCE DIST TOLERANCE

8/12/2019 emagtm


8/12/2019 emagtm



10-5

(2)

Figure 10.3 Generation of lines

Delete the lines numbered 6 through 11 using the command sequence (3) given below.

(3)

2 GRIDS CURSOR PICK

GEOMETRY LINE CREATE ON PRIM. CIRCLE

DELETE ENTITY-SETS LIN BORDEREXIT

8/12/2019 emagtm



10-6

Figure 10.4 Deletion of lines

Step 5 To generate a patch follow the following command sequences. Pick two lines to create a patch. In this example patches are created using two lines. This is shown in Figure 9.3.For example Patch #1 is created using line nos # 5 and 2.


CURSOR PICK


CURSOR PICK

8/12/2019 emagtm



10-7

Figure 10.5 Generation of patches

Step 6 To generate finite element mesh you can following command sequence. For example,you enter 8/8 in E1/E2 with ORDER 1, STIFFNESS TYPE 102 and MATERIAL ID 1.

Then pick patch # 3. Repeat this for patches 1 and 2, using E1/E2 as 8/12 and R1/R2 as1.0/0.4. Please note, if you have not changed ORDER, STIFFNESS TYPE andMATERIAL ID; they remain same, that is, 1, 102 and 1 respectively. This is shown inFigure 10.6.

FE GENRATION MESH FEG OPTION QUADRILATERAL

E1/E2 CURSOR PICKINPUT PATCH

8/12/2019 emagtm



10-8

Figure 10.6 Finite element generation on all patches using 2D elements of type 102 and order 1

Step 7 Once the finite element mesh is generated, user must delete all unreferenced nodes. Alsouser must merge the inactive nodes. This is an important step, because if inactive nodesare present in the FE model then the analysis results will not be correct. The final resultis shown in Figure 10.7.


ALL


ALL

8/12/2019 emagtm



10-9

Figure 10.7 Merging and deletion of inactive nodes

Step 8 Now user must define the material properties. In this capacitor problem there is only onematerial, that is, air. For air permittivity = 8.854 x 10-12 F/m.

In order to define permittivity of air follow the command syntax (1), see forms shown in Figure10.8a and 10.8b respectively. User will define the material constants depending on the analysistypes. For the capacitor, the user should enter the permittivity of air in the first column of EXX .

(1)

OR

(1)

NISA DATA GROUP NISA FORMS MATERIALEFIELD

FE GENERATION FE MODEL DATA

ADD

MATERIAL DATA

ADD Emag

Emag

8/12/2019 emagtm



10-10

Figure 10.8a Model data form

Figure10.8b Material property form

Step 9 Now user can define the boundary conditions for the capacitor model. The Dirichlet boundary condition is only defined, that is voltage = 0 volts, is defined on all the nodes

8/12/2019 emagtm



10-11

corresponding to Figure 10.0b and voltage = 100 volts on the nodes lying on the upper plate, as shown in Figure 10.9.

Now, in SET-ID put set-id number 1 (say); in SPEC. FIELD POT put value 0.0 and in NODE-ID select BORDER and choose the nodes stated earlier. Use left mouse button for each of them.Repeat the same with SPEC. FIELD POT as 100 for nodes on the upper plate.

Figure 10.9 Dirichlet boundary condition

Step 10 Finally, user must define the title, the EMAG control, and the executive command cards

such as analysis type, and sub analysis type. The forms of which are shown in Figures10.10, 10.11 and 10.12 respectively. Follow the command sequences given below.

TITLE

FE GENERATION BOUNDARY CONDN. SPFPOTEMAG

NISA DATA GROUP NISA FORMS TITLEEFIELD

ADD ON NODES

8/12/2019 emagtm



10-12

EMAG CONTROL



NISA DATA GROUP NISA FORMS EMAG CONTROLEFIELD

NISA DATA GROUP NISA FORMS EXECUTIVE

SUBA

EFIELD

8/12/2019 emagtm



10-13


Figure 10.12 SUB analysis form

8/12/2019 emagtm



10-14

Step 11 Futhermore, user must write .NIS, .DBS and .NEU files. NISA input file will be usedfor running the EMAG analysis, whereas .DBS (binary file) and NEU (ASCII file)contains the geometry and the finite element information of the model. The files arewritten by the following the procedure given below

Step 12 The program has its own editor and you may view and edit the NISA file. You areencouraged to view this file and understand the format of this file, which is thoroughlydocumented in the EMAG User’s manual. In many cases, you may make minorchanges and add more information regarding data groups which are not supportedthrough DISPLAY III. Figure 10.13 illustrates the NISA file.



FILE MANAGEMENT →→→→ WRITE →→→→ NISA FILE →→→→ filename →→→→

FILE MANAGEMENT →→→→ WRITE →→→→ DATABASE FILE →→→→ filename →→→→

FILE MANAGEMENT →→→→ WRITE →→→→ NEUTRAL FILE →→→→ filename →→→→

You should enter the name of the file in which you want to store the above files

8/12/2019 emagtm



10-15

Figure 9.12 Nisa file



RUNNING EMAG PROGRAM:

The next step is to run the analysis using EMAG. On workstations, user can type EMAG at prompt to run EMAG analysis. Whereas on PC choose option N in NISA386 menu OR executeEMAG through WINDOWS 95 if your version is WINDOWS based. Type the NISA input filename you had chosen earlier and hit <CR> to use the same file name as the output file.


FILE MANAGEMENT →→→→ QUIT PROGRAM →→→→ (Y)

8/12/2019 emagtm



10-16

1)

2)

Now user will see the form which contain the output parameters to be post processed, see Figure10.14.

Figure 10.14 Form for picking the Voltage

In this example we have chosen the Voltage to be viewed. Figure 10.15 shows the contour linesof the Voltage distribution.



8/12/2019 emagtm



10-17

Figure 10.15 The Voltage distribution

You can see the resultant electric field arrow plots using the following command sequence. Thisis shown in Figure 10.16

POST RESULTS MISC. RESULTS EMAG ARROW PLOTS

ELECTRIC FIELD

VIEW DISPLAY OPTIONS BOUNDARY LINE

ALL ELEMENTS

8/12/2019 emagtm



10-18

Figure 10.16 The arrow field plot for the electric field

8/12/2019 emagtm



11-1

CHAPTER 11

MODELING SESSION 4

The problem of a very long (can be considered infinite) H-shaped copper bus bar is consideredcarrying a uniform current density of Jz = 100.0 Amp/m2 . The uniform cross-section of the bus bar is H-shaped and lies in the XY plane. The problem geometry is shown in Figure 11.0a. Youhave to determine the magnetic vector potential, the resultant magnetic flux density, the resultanteddy current density and the induced electric field distribution in the problem region.

0.06

Y

0.02

X

0.02 0.02 0.02

Z


Figure 11.0a H-shaped copper bus bar

The material property (permeability and conductivity) of the copper and the air medium are

defined as follows :

Material = IsotropicMUXX (copper) = 795780.0 m/HSIXX (copper) = 5.8 x 10+07 mho/mMUXX (air) = 795780.0 m/HSIXX (air) = 0.0 mho/m

8/12/2019 emagtm



11-2

The H-shaped copper bus bar is very long in the direction perpendicular to this page. Hence, onlya 2D model of the problem is necessary. This 2D model is taken in the XY plane. The H-shape ishorizontal with respect to the X-axis and is centred with respect to the origin of the XYcoordinate system. On both the X and Y-axis the Magnetic field is normal to the respective axesand its tangential component is zero. Hence, only a fourth of the 2D model is necessary for

analysis; which is taken as the first quadrant. On the infinite portion of the first quadrant themagnetic vector potential A is set to 0 . This is shown in Figure 10.0b.

Y

The magnetic vector potential = 0 on all the infinite portions of the first quadrant

0.02

0.02 Jz =100 0.03

X0.01 0.1

Figure 11.0b The portion in 2D required for analysis

Since the geometry of the H-shaped copper bus bar model is in 2D, therefore Quadrilateralelements are chosen. NISA offers one of the most complete element libraries among commercialsoftwares, and a list of currently available elements can be found in the User’s manual.

The first step in modeling this problem is to create the geometry of one-fourth of the bus barcross-section in terms of lines. The lines are created by joining grids (points in space with predefined coordinates). These lines are used to create surfaces called patches. Once thegeometry is obtained in terms of patches, mesh generation capability of the package is used and amesh is created. Then, excitation (i.e., current density) and the boundary conditions along withmaterial and geometric properties are defined for the elements. Furthermore, analysis and subanalysis types are defined at this stage. Finally, at the end of modeling a NISA file is writen to perform an Magnetodynamic analysis.

Invoke DISPLAY III on your computer. When the screen appears click mouse on the COM HOT button ( or hit kay ‘c’ on the keyboard ) to get into the command mode. Now enter the followingcommands interactively to generate the model.

8/12/2019 emagtm


8/12/2019 emagtm



11-48

Figure 11.1 Distribution of real part of the magnetic vector potential

8/12/2019 emagtm



11-49


8/12/2019 emagtm



12-1

CHAPTER 12

MODELING SESSION 5

The problem of a long C-shaped magnetic core with an air gap is considered. The uniform cross-section of the magnetic core is C-shaped and lies in the XY plane. The problem geometry isshown in Figure 12.0a. The excitation in the coil is time varying and is given by the Table 12.1.You have to determine the magnetic vector potential, the resultant magnetic flux density, theresultant eddy current density and the induced electric field distribution in the problem region atdifferent time steps.

C-shaped magnetic core

coils0.065 Air medium

Air0.04 0.02 0.25

Air gap

0.020.05

0.25


Figure 12.0a C-shaped magnetic core excited by the current in the coils

The material property (permeability and conductivity) of the iron, copper and the air mediumsurrounding the core is defined as follows :

Material = IsotropicMUXX (copper) = 795780.0 m/HSIXX (copper) = 6.0 x 10+07 mho/mMUXX (iron) = 400.0 m/H

SIXX (iron) = 5.0 x 10+07

mho/mMUXX (air) = 795780.0 m/HSIXX (air) = 0.0 mho/m

The C-shaped magnetic core is long in the direction perpendicular to this page. Hence, only a 2Dmodel of the problem is necessary. This 2D model is taken in the XY plane. The C-shape ishorizontal with respect to the X axis and its left bottom corner lies at the origin of the XY

8/12/2019 emagtm


8/12/2019 emagtm



12-3

The first step in modeling this problem is to create the geometry of magnetic core cross-sectionin terms of lines as shown in Figures 12.0a and b. The lines are created by joining grids (pointsin space with predefined coordinates). These lines are used to create surfaces called patches.Once the geometry is obtained in terms of patches, mesh generation is used and the mesh iscreated. Then, excitation (i.e., current density) and the boundary conditions along with material

and geometric properties are defined for the elements. Furthermore, analysis and sub analysistypes are defined at this stage. Finally, at the end of modeling a NISA file is created for performing an Transient Magnetic analysis.


COMMANDS DESCRIPTION

SET,TOLC,.1E-04 Since the dimensions are of order

SET,TOLD,.1E-04 or 0.01 or less set the PICK and

DIST tolerance to 100 times less

GRD,ADD,1,0.0/0.0/0.0 Create grid at the origin of the

global coordinate system (0/0/0)

GRD,ADD,2,0.05/0.0/0.0 Create grid # 2 at (0.05/0/0)





GRD,TRS,1T6,B7/1,0.0/0.05/0.0/0,1

Translate grids #1 through #6 by

distance 0.05 in the Y direction

and number them 7 through 12

GRD,TRS,7T12,B13/1,0.0/0.055/0.0/0,1


Distance 0.055 in the Y direction


GRD,TRS,18,19,0.02/0.0/0.0/0,1

Translate grids #18 by Distance

0.02 in the X direction and number

it 19

GRD,TRS,13,20,-0.02/0.0/0.0/0,1

Translate grids #13 by Distance-0.02 in the X direction and

number it 20

GRD,TRS,13T20,B21/1,0.0/0.01/0.0/0,1


Distance 0.01 in the Y direction


GRD,MIR,1T28,B29/1,Y0.125

8/12/2019 emagtm



12-4

Mirror grids #1 through #28 about

XZ plane at Y = 0.125 and number

them 29 through 56

LIN,2GD,1,2,1 Join grids 1, 2 to create line # 1







LIN,2GD,9,10,8 Join grids 9, 10 to create line #8

LIN,2GD,10,11,9 Join grids 10,11 to create line #9

LIN,2GD,11,12,10 Join grids 11,12 to create line #

10


11


12


13


14


15


16


17



19


20


21


22


23LIN,2GD,26,27,24 Join grids 26,27 to create line #

24

LIN,MIR,1T24,B27/1,Y0.125 Mirror lines 1 through 24 about

the XZ plane at Y = 0.125 creating

lines starting at numbers 27

PAT,2LN,6,1,1 Use lines 6 and 1 to create patch

# 1

8/12/2019 emagtm



12-5


# 2


# 3


# 4


# 5


# 6


# 7


# 8


# 9

PAT,2LN,16,10,10 Use lines 16 and 10 to create

patch # 10


patch # 11


patch # 12


patch # 13


patch # 14


patch # 15

PAT,2LN,23,16,16 Use lines 23 and 16 to createpatch # 16


patch # 17


patch # 18


patch # 19


patch # 20


patch # 21PAT,2LN,48,22,22 Use lines 48 and 22 to create

patch # 22


Patch # 23


patch # 24

PAT,MIR,1T17,B25/1,Y0.125 Mirror patches 1 through 17 about

8/12/2019 emagtm



12-6

the XZ plane at Y = 0.125 creating

patches starting at numbers 25

PAT,NLIN,0/0/0 Set patch plotting lines as 0/0/0

SET,LABA,OFF Set all labels off

PAT,LAB,ON Set Patch labels on

FEG,QUA,1,,,2/2,102/1/1/ Mesh patch # 1 using E1/E2 as 2/2,

order as 1, stiffness type as 102

and material as 1



and material as 1



and material as 1



and material as 1



and material as 1



and material as 1

FEG,QUA,10,,,2/2,102/1/1/ Mesh patch #10 using E1/E2 as 2/2,


and material as 1



and material as 1FEG,QUA,16,,,2/2,102/1/1/ Mesh patch #16 using E1/E2 as 2/2,


and material as 1



and material as 1



and material as 1


order as 1, stiffness type as 102and material as 1



and material as 1



and material as 1

8/12/2019 emagtm



12-7



and material as 1



and material as 1



and material as 1



and material as 1



and material as 1



and material as 2



and material as 2



and material as 2



and material as 2


order as 1, stiffness type as 102and material as 2



and material as 2



and material as 2



and material as 2

FEG,QUA,31,,,2/2,102/1/2/ Mesh patch #31 using E1/E2 as 2/2,order as 1, stiffness type as 102

and material as 2



and material as 2



8/12/2019 emagtm



12-8

and material as 2



and material as 2



and material as 2



and material as 2

FEG,QUA,15,,,2/2,102/1/2/ , Mesh patch #15 using E1/E2 as 2/2,


and material as 2

FEG,QUA,17,,,2/2,102/1/2/ , Mesh patch #17 using E1/E2 as 2/2,


and material as 2



and material as 3



and material as 3



and material as 3



and material as 3

FEG,QUA,18,,,2/2,102/1/3/ Mesh patch #18 using E1/E2 as 2/2,order as 1, stiffness type as 102

and material as 3



and material as 3

NOD,CLN,ALL Delete all inactive nodes

NOD,MER,ALL,.1E-04 Merge all nodes with tolerance

0.1E-04

Y Type Y

NOD,CMP,ALL,1 Compact all node numbers

ELE,CMP,ALL,1 Compact all element numbersMAT,ADD,1,MUXX,400.0,0 For material # 1 (iron) put

permeability value

MAT,ADD,1,SIXX,.5E+08,0 For material # 1 (iron) put

conductivity value

MAT,ADD,2,MUXX,795780.0,0 For material # 2 (air) put

permeability value

MAT,ADD,3,MUXX,795780.0,0 For material # 3 (copper) put

8/12/2019 emagtm



12-9

permeability value

MAT,ADD,3,SIXX,.6E+08,0 For material # 3 (copper) put

conductivity value

SFP,ADD,BRD,1,0.0, Put Dirichlet boundary condition (

A = 0) using BORDER and picking

all nodes on the boundary as

listed below

ENTITY-IDS: 58

1 4 7 8 9 10 13 26

27 35 36 44 45 48 51 53

54 57 60 97 103 106 112 115

116 117 125 126 134 135 143 144

147 150 152 153 156 159 192 195

198 294 296 297 325 328 331 332

337 340 346 349 350 362 365 366

367 368

CRD,ADD,BOX,2,0.0/0.0/-1.0/0.0/0.0, /1

Put source current density ( Jz

= -1.0) using BORDER and picking

all elements on the coil side as

listed below. Put Time Amplitude

curve number = 1

ENTITY-IDS: 12

133 134 135 136 137 138 139 140

141 142 143 144

CRD,ADD,BOX,2,0.0/0.0/1.0/0.0/0.0, /1


= 1.0) using BORDER and picking

all elements on the coil side aslisted below. Put Time Amplitude

curve number = 1

ENTITY-IDS: 12

145 146 147 148 149 150 151 152

153 154 155 156

NFORM Use NISA DATA FORMS → NISA FORM.

Then do the following :

1.Select MFIELD.

a. Then select EMAG CONTROL, enter number of iteration =

10 (say) and save itb. Select TITLE, enter title and save it

c. Select TIME AMPLITUDE → ADD with IDCURVE #1, enter the

current values as given in table 12.1 and save it

d. Select TIME INTEGRATION → ADD : integration scheme as

backward difference = 1.0, initial step size = 10.0

and maximum time = 200.0

8/12/2019 emagtm



12-10

e. Select FPOTOUT → ADD : EMAG ANALYSIS ID = 1, number of

step selections = 1, Starting time = 0.0, ending time

= 200.0 and increment = 10.0

f. Select FPOTHISTORY → ADD : number of nodes = 1 and the

node number = 14.

2.Select EXECUTIVE → MFIELD, select SUBA → TMAG and enterfilename for post file.

WRI NIS CCORE.NIS Save NISA file in CCORE.NIS

END End the DISPLAY III session

This completes the pre-processing (or modeling) phase of the problem.

Now you should use a text editor to edit CCORE.NIS file (or you can use editor available insideDISPLAY III, as shown in modeling session 1). You can edit this file if the EXECUTIVE cardsare not correct. Save the file (if modified) under the same name. The correct NISA file should

look as shown below

**EXECUTIVE

ANAL=MFIELD

SUBA=TMAG

FILE=CCORE

SAVE=26

*TITLE

C-shaped magnetic core with airgap (Transient Analysis)

*ELTYPE

1, 102, 1

*NODES1,,,, 0.00000E+00, 1.15000E-01, 0.00000E+00, 0

2,,,, 0.00000E+00, 1.10000E-01, 0.00000E+00, 0

3,,,, 0.00000E+00, 1.05000E-01, 0.00000E+00, 0

4,,,, 2.50000E-02, 1.15000E-01, 0.00000E+00, 0

5,,,, 2.50000E-02, 1.10000E-01, 0.00000E+00, 0

••••••

••••••

••••••

*ELEMENTS

1, 1, 1, 2, 0

1, 2, 5, 4,2, 1, 1, 2, 0

2, 3, 6, 5,

3, 1, 1, 2, 0

4, 5, 8, 7,

4, 1, 1, 2, 0

5, 6, 9, 8,

5, 1, 1, 2, 0

8/12/2019 emagtm


8/12/2019 emagtm



12-12

106,,,,1

.000E+00, .000E+00, 1.0E+00, .000E+00, .000E+00

107,,,,1

.000E+00, .000E+00, 1.0E+00, .000E+00, .000E+00

108,,,,1

.000E+00, .000E+00, 1.0E+00, .000E+00, .000E+00

109,,,,1

.000E+00, .000E+00, 1.0E+00, .000E+00, .000E+00

110,,,,1

.000E+00, .000E+00, 1.0E+00, .000E+00, .000E+00

111,,,,1

.000E+00, .000E+00, 1.0E+00, .000E+00, .000E+00

112,,,,1

.000E+00, .000E+00, 1.0E+00, .000E+00, .000E+00

113,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

114,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

115,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

116,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

117,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

118,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

119,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

120,,,,1.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

121,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

122,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

123,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

124,,,,1

.000E+00, .000E+00,-1.0E+00, .000E+00, .000E+00

*FPOTHISTORY

1,14*FPOTOUT

**Output control**

0,200.0,10.0

*ENDDATA

8/12/2019 emagtm



12-13

Now you can run the EMAG solver. For DOS version execute NISA386 and choose ELECTRO-MAG (N); for WINDOWS version run EMAGS; for WORKSTATIONS execute EMAG. AT prompt for the input file name type : CCORE.NIS and accept the default CCORE.OUT as theoutput file name.

POST-PROCESSING :

DISPLAY III can now be used to view the results of the analysis graphically. A file namedCCORE26.DAT will be created by the EMAG solver when you run it (remember you had giventhe post filename as CCORE). This file is needed for post-processing.

Invoke DISPLAY III on your computer. The EMRC logo appears on the screen and the programis ready for interactive usage. By default, the menu mode becomes active so that the user can usethe mouse to execute different commands interactively.

To use this manual effectively, we suggest that you get into the command mode and execute the

commands discussed here by typing in from keyboard. After getting comfortable with this procedure, you should experiment with the menu mode and follow similar steps for post- processing results.

To get into the command mode, you need to move the cursor into the area on the screendisplaying ‘COMMAND’ and hit the ENTER key. You may also type in the letter ‘C’ to get intothe command mode.

For this session only one plot is viewed. You are encouraged to make use of the on-line HELPoption and experiment with various other options available to generate other plots of interest.

For post-processing, type the following commands


REA,POS,CCORE Read the post-processing data file

CTR,ADD,MVP Select contour as the

magnetic vector potential

CTR,CLB,LNUM Select contours with lines and

numbers

PST,CSS,1 Select plot for time = 0.0

PLO Plot the contours

PST,CSS,4 Select plot for time = 40.0

PLO Plot the contours

8/12/2019 emagtm


8/12/2019 emagtm



12-15

Figure 12.2 The magnetic vector potential distribution at time t = 40.0 sec

8/12/2019 emagtm



12-16


8/12/2019 emagtm



13-1

CHAPTER 13

MODELING SESSION 6

The problem of a three dimensional transformer is considered. The transformer core is alignedwith the XY plane and is made of a magnetic material like steel. The coil is made of copper. The problem geometry is shown in Figure 13.0. The excitation in the coil is assumed to be DC. Youhave to determine the magnetic scalar potential, the resultant magnetic flux density and theresultant magnetic field intensity distribution in the problem region.

(All dimensions in metres)

Figure 13.0 3 Dimensional Transformer excited by a DC current in the one coil

Transformer :

l = 20 cmh = 20 cms = 16 cmw = 2 cmExterior Region :L = 20 cmH = 20 cmW = 11.5 cmCoil :lc = 4 cmwc = 0.5 cmJ = Jx = Jx =

1.6 x 106 A/m2

Y

Z X

0=∂

∂

n

φ φ = 0

φ = 0

8/12/2019 emagtm



13-2

The material property (permeability) of the steel, copper and the air medium surrounding thecore is defined as follows:

Material = IsotropicMUXX (steel) = 5.867 x 10-03 H/m

MUXX (air) = 12.56 x 10

-07

H/mMUXX (copper) = 12.56 x 10-07 H/m

The three-dimensional core of the Transformer is aligned with the XY plane. It can be easilyseen that the transformer is symmetric with respect to all the three coordinate planes viz : XY,YZ and ZX. Hence, only a one-eighth of the model of the problem is necessary for solution. It isassumed that the magnetic scalar potential φm tends to 0 on the boundary shown in Figure 13.0.

Since the geometry of the Transformer model is in 3D, 3D Hexahedral element is chosen. NISAoffers one of the most complete element libraries among commercial softwares, and a list ofcurrently available elements can be found in the User’s manual.

The first step in modeling this problem is to create the geometry of the transformer in terms oflines as shown in Figures 13.0. The lines are created by joining grids (points in space with predefined coordinates). These lines are used to create surfaces called patches. These plane patches are employed to create hyperpatches such that these hyperpatches fully cover thetransformer model. Once the geometry is obtained in terms of hyperpatches, mesh generation isused and the mesh is created. Then, excitation (i.e., DC current density) and the boundaryconditions along with material and geometric properties are defined for the elements.Furthermore, analysis and sub analysis types are defined at this stage. Finally, at the end ofmodeling a NISA file is obtained to perform a Three-dimensional Magnetostatic analysis usingthe magnetic scalar potential.






GRD,ADD,1,0/0/0 Create grid at the origin of the


GRD,ADD,2,0.02/0/0 Create grid # 2 at (0.02/0/0)




GRD,TRS,1T5,B6/1,0.0/0.02/0.0/0,1

Translate grids 1 through 5 by

0.02 in Y direction

GRD,TRS,1T5,B11/1,0.0/0.08/0.0/0,1

8/12/2019 emagtm



13-3


0.08 in Y direction

GRD,TRS,1T5,B16/1,0.0/0.1/0.0/0,1


0.1 in Y direction

GRD,TRS,1T5,B21/1,0.0/0.2/0.0/0,1


0.2 in Y direction

GRD,TRS,1/6/11/16/21,B26/1,0.2/0.0/0.0/0,1

Translate grids 1/6/11/16/21 by

0.2 in X direction





LIN,2GD,5,26,5 Join grids 5,26 to create line # 5

LIN,TRS,1T5,B6/1,.0/.02/.0/0,1

Translate lines 1 through 5 by

0.02 in the Y direction

LIN,TRS,1T5,B11/1,.0/.08/.0/0,1



LIN,TRS,1T5,B16/1,.0/.1/.0/0,1



LIN,TRS,1T5,B21/1,.0/.2/.0/0,1



SET,LABA,OFF Set all labels offPAT,2LN,6,1,1 Use lines 6 and 1 to create patch

# 1


# 2


# 3


# 4


# 5

PAT,2LN,11,6,6 Use lines 11 and 6 to create patch# 6


# 7


# 8


# 9

8/12/2019 emagtm



13-4

PAT,2LN,15,10,10 Use lines 15 & 10 to create patch

# 10


# 11


# 12


# 13


# 14


# 15


# 16


# 17


# 18


# 19


# 20


PAT,TRS,1T20,B21/1,0.0/0.0/-0.01/0,1

Translate patches #1 through # 20

by –0.01 in the Z direction

PAT,TRS,1T20,B41/1,0.0/0.0/-0.015/0,1


by –0.015 in the Z directionPAT,TRS,1T20,B61/1,0.0/0.0/-0.115/0,1


by –0.115 in the Z direction

HYP,2PA,1T20,21T40 Create hyperpatches by using patch

set from 1 to 20 and patch set

from 21 to 40


set from 21 to 40 and patch set

from 41 to 60


set from 41 to 60 and patch setfrom 61 to 80

HYP,NLIN,0/0/0 Set hyperpatch plotting lines as

0/0/0

VEW,HID,ON Put hidden lines for element

plotting on

ELE,PAI,MAT Set element painting by material

on

8/12/2019 emagtm


8/12/2019 emagtm



13-6

FEG,HEX,17,,,1/6/2,//2/,1.0/0.25/1.0

Mesh hyperpatch #17 using E1/E2/E3

as 1/6/2,order as 1,stiffness type

as 104, R1/R2/R3 as 1.0/0.25/1.0

and material as 2

FEG,HEX,20,,,6/6/2,//2/,4.0/0.25/1.0



as 104, R1/R2/R3 as 1.0/0.25/1.0

and material as 2

FEG,HEX,21,,,3/3/1,104//3/,1.0/1.0/1.0



as 104, R1/R2/R3 as 1.0/1.0/1.0

and material as 3

FEG,HEX,22,,,1/3/1,104//3/,1.0/1.0/1.0



as 104, R1/R2/R3 as 1.0/1.0/1.0

and material as 3

FEG,HEX,24/31/34,,,3/3/1,104//2/,1.0/1.0/1.0

Mesh hyperpatches #24/31/34

using E1/E2/E3 as 3/3/1,order as

1,stiffness type as 104, R1/R2/R3

as 1.0/1.0/1.0 and material as 2

FEG,HEX,26/29,,,3/6/1,104//2/,1.0/1.0/1.0

Mesh hyperpatches #26/29 using

E1/E2/E3 as 3/6/1,order as

1,stiffness type as 104, R1/R2/R3as 1.0/1.0/1.0 and material as 2

FEG,HEX,23,,,6/3/1,104//2/,1.0/1.0/1.0



as 104, R1/R2/R3 as 1.0/1.0/1.0

and material as 2

FEG,HEX,27,,,1/6/1,104//2/,1.0/1.0/1.0



as 104, R1/R2/R3 as 1.0/1.0/1.0

and material as 2FEG,HEX,28,,,6/6/1,104//2/,1.0/1.0/1.0



as 104, R1/R2/R3 as 1.0/1.0/1.0

and material as 2

FEG,HEX,25/35,,,6/3/1,104//2/,4.0/1.0/1.0


8/12/2019 emagtm



13-7




FEG,HEX,30,,,6/6/1,104//2/,4.0/1.0/1.0



as 104, R1/R2/R3 as 4.0/1.0/1.0

and material as 2

FEG,HEX,36,,,3/6/1,104//2/,1.0/0.25/1.0



as 104, R1/R2/R3 as 1.0/0.25/1.0

and material as 2

FEG,HEX,37,,,1/6/1,104//2/,1.0/0.25/1.0



as 104, R1/R2/R3 as 1.0/0.25/1.0

and material as 2

FEG,HEX,38,,,6/6/1,104//2/,1.0/0.25/1.0



as 104, R1/R2/R3 as 1.0/0.25/1.0

and material as 2

FEG,HEX,39,,,3/6/1,104//2/,1.0/0.25/1.0



as 104, R1/R2/R3 as 1.0/0.25/1.0

and material as 2

FEG,HEX,40,,,6/6/1,104//2/,4.0/0.25/1.0Mesh hyperpatch #40 using E1/E2/E3


as 104, R1/R2/R3 as 4.0/0.25/1.0

and material as 2

FEG,HEX,41/44/51/54,,,3/3/6,104//2/,1.0/1.0/4.0

Mesh hyperpatches #41/44/51/54

using E1/E2/E3 as 3/3/6,order as



FEG,HEX,46/49,,,3/6/6,104//2/,1.0/1.0/4.0

Mesh hyperpatch #46/49 usingE1/E2/E3 as 3/6/6,order as



FEG,HEX,43/53,,,6/3/6,104//2/,1.0/1.0/4.0




8/12/2019 emagtm



13-8


FEG,HEX,42/52,,,1/3/6,104//2/,1.0/1.0/4.0





FEG,HEX,47,,,1/6/6,104//2/,1.0/1.0/4.0



as 104, R1/R2/R3 as 1.0/1.0/4.0

and material as 2

FEG,HEX,48,,,6/6/6,104//2/,1.0/1.0/4.0



as 104, R1/R2/R3 as 1.0/1.0/4.0

and material as 2

FEG,HEX,45/55,,,6/3/6,104//2/,4.0/1.0/4.0





FEG,HEX,50,,,6/6/6,104//2/,4.0/1.0/4.0



as 104, R1/R2/R3 as 4.0/1.0/4.0

and material as 2

FEG,HEX,56/59,,,3/6/6,104//2/,1.0/0.25/4.0


E1/E2/E3 as 3/6/6,order as1,stiffness type as 104, R1/R2/R3


FEG,HEX,57,,,1/6/6,104//2/,1.0/0.25/4.0



as 104, R1/R2/R3 as 1.0/0.25/4.0

and material as 2

FEG,HEX,58,,,6/6/6,104//2/,1.0/0.25/4.0



as 104, R1/R2/R3 as 1.0/0.25/4.0and material as 2

FEG,HEX,60,,,6/6/6,104//2/,4.0/0.25/4.0



as 104, R1/R2/R3 as 4.0/0.25/4.0

and material as 2

PLO Regenerate the plot

8/12/2019 emagtm



13-9

NOD,CLN,ALL Delete all inactive nodes


0.1E-04

Y Type Y


ELE,CMP,ALL,1 Compact all element numbers

VEW,BND,ON Put boundary line viewing on


VEW,BND,OFF Put boundary line viewing off

MAT,ADD,1,MUXX,.005867,0 For material # 1 (steel) put

permeability value

MAT,ADD,2,MUXX,.1256E-05,0 For material # 2 (air) put

permeability value

MAT,ADD,3,MUXX,.1256E-05,0 For material # 3 (copper) put

permeability value

SFP,ADD,BRD,1,0.0, Put Dirichlet boundary condition (

φm = 0) using BORDER and pickingall nodes on the boundary as

listed below

ENTITY-IDS: 570

13 14 15 16 29 30 31 32

45 46 47 48 61 62 63 64

77 78 79 80 93 94 95 96

331 332 333 334 335 336 355 356

357 358 359 360 379 380 381 382

383 384 552 558 564 565 566 567

568 569 570 576 582 588 589 590

591 592 593 594 600 606 612 613

614 615 616 617 618 624 630 636642 648 654 660 666 672 678 684

690 696 702 708 714 720 726 732

738 744 750 756 762 768 774 780

781 782 783 784 805 806 807 808

829 830 831 832 853 854 855 856

877 878 879 880 901 902 903 904

925 926 927 928 929 930 961 962

963 964 965 966 997 998 999 1000

1001 1002 1033 1034 1035 1036 1037 1038

1044 1050 1056 1062 1068 1069 1070 1071

1072 1073 1074 1080 1086 1092 1098 11041105 1106 1107 1108 1109 1110 1116 1122

1128 1134 1140 1153 1154 1155 1156 1160

1173 1174 1175 1176 1264 1265 1266 1267

1268 1310 1316 1322 1323 1324 1325 1326

1327 1328 1334 1340 1346 1352 1358 1364

1370 1376 1382 1383 1384 1385 1386 1407

1414 1415 1416 1417 1418 1419 1455 1456

8/12/2019 emagtm



13-10

1457 1473 1474 1475 1476 1477 1478 1484

1490 1496 1502 1508 1521 1522 1523 1524

1537 1538 1539 1540 1553 1554 1555 1556

1569 1570 1571 1572 1585 1586 1587 1588

1601 1602 1603 1604 1617 1618 1619 1620

1633 1634 1635 1636 1649 1650 1651 1652

1665 1666 1667 1668 1681 1682 1683 1684

1697 1698 1699 1700 2151 2152 2153 2154

2155 2156 2175 2176 2177 2178 2179 2180

2199 2200 2201 2202 2203 2204 2223 2224

2225 2226 2227 2228 2247 2248 2249 2250

2251 2252 2271 2272 2273 2274 2275 2276

2618 2624 2630 2631 2632 2633 2634 2635

2636 2642 2648 2654 2655 2656 2657 2658

2659 2660 2666 2672 2678 2679 2680 2681

2682 2683 2684 2690 2696 2702 2703 2704

2705 2706 2707 2708 2714 2720 2726 2727

2728 2729 2730 2731 2732 2738 2744 2750

2751 2752 2753 2754 2755 2756 2762 2768

2774 2780 2786 2792 2798 2804 2810 2816

2822 2828 2834 2840 2846 2852 2858 2864

2870 2876 2882 2888 2894 2900 2906 2912

2918 2924 2930 2936 2942 2948 2954 2960

2966 2972 2978 2984 2990 2996 3002 3008

3014 3020 3026 3032 3038 3044 3050 3056

3062 3068 3074 3080 3081 3082 3083 3084

3105 3106 3107 3108 3129 3130 3131 3132

3153 3154 3155 3156 3177 3178 3179 3180

3201 3202 3203 3204 3225 3226 3227 32283249 3250 3251 3252 3273 3274 3275 3276

3297 3298 3299 3300 3321 3322 3323 3324

3345 3346 3347 3348 3369 3375 3381 3387

3393 3399 3405 3406 3407 3408 3409 3435

3436 3437 3438 3439 3465 3466 3467 3468

3469 3495 3496 3497 3498 3499 3525 3526

3527 3528 3529 3555 3556 3557 3558 3559

3585 3586 3587 3588 3589 3590 3596 3602

3608 3614 3620 3621 3622 3623 3624 3625

3626 3632 3638 3644 3650 3656 3657 3658

3659 3660 3661 3662 3668 3674 3680 36863692 3693 3694 3695 3696 3697 3698 3704

3710 3716 3722 3728 3729 3730 3731 3732

3733 3734 3740 3746 3752 3758 3764 3765

3766 3767 3768 3769 3770 3776 3782 3788

3794 3800

VEW,LEFT

SFP,ADD,BOX,1,0.0, Put Dirichlet boundary condition (

8/12/2019 emagtm



13-11

φm = 0) using BOX and pickingall nodes on the boundary as

listed below

ENTITY-IDS: 380

1589 1590 1591 1592 1593 1594 1595 1596

1597 1598 1599 1600 1601 1602 1603 16041685 1686 1687 1688 1689 1690 1691 1692

1693 1694 1695 1696 1697 1698 1699 1700

1781 1782 1783 1784 1785 1786 1787 1788

1789 1790 1791 1792 1793 1794 1795 1796

1877 1878 1879 1880 1881 1882 1883 1884

1885 1886 1887 1888 1889 1890 1891 1892

1993 1994 1995 1996 1997 1998 1999 2000

2001 2002 2003 2004 2005 2006 2007 2008

2009 2010 2011 2012 2113 2114 2115 2116

2117 2118 2119 2120 2121 2122 2123 2124

2125 2126 2127 2128 2129 2130 2131 2132

2253 2254 2255 2256 2257 2258 2259 2260

2261 2262 2263 2264 2265 2266 2267 2268

2269 2270 2271 2272 2273 2274 2275 2276

2409 2410 2411 2412 2413 2414 2415 2416

2417 2418 2419 2420 2421 2422 2423 2424

2425 2426 2427 2428 2429 2430 2431 2432

2458 2459 2460 2461 2462 2588 2589 2590

2591 2592 2593 2594 2595 2596 2597 2598

2599 2600 2601 2602 2603 2604 2605 2606

2607 2608 2609 2610 2611 2612 2733 2734

2735 2736 2737 2738 2739 2740 2741 2742

2743 2744 2745 2746 2747 2748 2749 27502751 2752 2753 2754 2755 2756 2877 2878

2879 2880 2881 2882 2883 2884 2885 2886

2887 2888 2889 2890 2891 2892 2893 2894

2895 2896 2897 2898 2899 2900 3051 3052

3053 3054 3055 3056 3057 3058 3059 3060

3061 3062 3063 3064 3065 3066 3067 3068

3069 3070 3071 3072 3073 3074 3075 3076

3077 3078 3079 3080 3201 3202 3203 3204

3205 3206 3207 3208 3209 3210 3211 3212

3213 3214 3215 3216 3217 3218 3219 3220

3221 3222 3223 3224 3345 3346 3347 33483349 3350 3351 3352 3353 3354 3355 3356

3357 3358 3359 3360 3361 3362 3363 3364

3365 3366 3367 3368 3399 3400 3401 3402

3403 3404 3555 3556 3557 3558 3559 3560

3561 3562 3563 3564 3565 3566 3567 3568

3569 3570 3571 3572 3573 3574 3575 3576

3577 3578 3579 3580 3581 3582 3583 3584

8/12/2019 emagtm



13-12

3765 3766 3767 3768 3769 3770 3771 3772

3773 3774 3775 3776 3777 3778 3779 3780

3781 3782 3783 3784 3785 3786 3787 3788

3789 3790 3791 3792 3793 3794 3795 3796

3797 3798 3799 3800

YG

VEW,TOP View along XY plane looking

through Z axis

ELE,ERA,MAT/1T2 Erase all elements of material 1 &

2

PLO,ACT Plot all active entities

VEW,TOP View along XY plane looking

through Z axis

CRD,ADD,BOX,2,0/0/-1.0E6/0/0,


= -1.0E6) using BOX and picking

elements on the coil as listed

below.

ENTITY-IDS: 9

223 224 225 226 227 228 694 695

696

CRD,ADD,BOX,2,-1.0E6/0/0/0/0,

Put source current density ( Jx

= -1.0E6) using BOX and picking

elements on the coil as listed

below.

ENTITY-IDS: 9

685 686 687 688 689 690 691 692

693NFORM Use NISA DATA FORMS → NISA FORM.

Then do the following :

1.Select MFIELD.

a. Then select EMAG CONTROL, and save it

b. Select TITLE, enter title and save it

2.Select EXECUTIVE → MFIELD, select SUBA → MGSS and enter

filename for post file.

WRI NIS TRANS3D.NIS Save NISA file in TRANS3D.NIS

END End the DISPLAY III session

This completes the pre-processing (or modeling) phase of the problem.

Now you should use a text editor to edit TRANS3D.NIS file (or you can use editor availableinside DISPLAY III, as shown in modeling session 1). You can edit this file if the EXECUTIVEcards are not correct. You have to enter the CURSYM card in NISA file because it cannot beentered in DISPLAY III. First, enter *CURSYM after the *CURDEN cards. Since you have

8/12/2019 emagtm


8/12/2019 emagtm



13-14

8, 1, 1, 1, 0

10, 11, 15, 14, 26, 27, 31, 30,

9, 1, 1, 1, 0

11, 12, 16, 15, 27, 28, 32, 31,

10, 1, 1, 1, 0

17, 18, 22, 21, 33, 34, 38, 37,

•••••• ••••••

••••••

*MATEMAG

MUXX, 1,0, 0,0.005867,0

MUXX, 2,0, 0,0.1256E-05,0

MUXX, 3,0, 0,0.1256E-05,0

MUXX, 4,0, 0,0.1256E-05,0

*EMAGCNTL, ID= 11,1,1,0.001,1.0

*SPFPOT

** SPFPOT SET = 1

1, 0.00000E+00

2, 0.00000E+00

3, 0.00000E+00

4, 0.00000E+00

17, 0.00000E+00

18, 0.00000E+00

19, 0.00000E+00

20, 0.00000E+00

•••••• ••••••

••••••

*CURDEN

** CURDEN SET = 1

187,,,,,

0.000E+00,0.000E+00,-.100E+07,0.000E+00,0.000E+00

188,,,,,

0.000E+00,0.000E+00,-.100E+07,0.000E+00,0.000E+00

189,,,,,

0.000E+00,0.000E+00,-.100E+07,0.000E+00,0.000E+00

190,,,,,

0.000E+00,0.000E+00,-.100E+07,0.000E+00,0.000E+00

191,,,,,

0.000E+00,0.000E+00,-.100E+07,0.000E+00,0.000E+00

192,,,,,

0.000E+00,0.000E+00,-.100E+07,0.000E+00,0.000E+00

8/12/2019 emagtm



13-15

685,,,,,

-.100E+07,0.000E+00,0.000E+00,0.000E+00,0.000E+00

686,,,,,

-.100E+07,0.000E+00,0.000E+00,0.000E+00,0.000E+00

687,,,,,

-.100E+07,0.000E+00,0.000E+00,0.000E+00,0.000E+00

688,,,,,

-.100E+07,0.000E+00,0.000E+00,0.000E+00,0.000E+00

689,,,,,

-.100E+07,0.000E+00,0.000E+00,0.000E+00,0.000E+00

690,,,,,

-.100E+07,0.000E+00,0.000E+00,0.000E+00,0.000E+00

•••••• •••••• ••••••

*CURSYM

8

JX,1,1,-1

JZ,-1,1,1

*ENDDATA

Now you can run the EMAG solver. For DOS version execute NISA386 and choose ELECTRO-MAG (N); for WINDOWS version run EMAGS; for WORKSTATIONS execute EMAG. AT prompt for the input file name type : TRANS3D.NIS and accept the default TRANS3D.OUT asthe output file name.

POST-PROCESSING :

DISPLAY III can now be used to view the results of the analysis graphically. A file namedTRANS3D26.DAT is created by the EMAG solver when you run it (remember you had giventhe post filename as TRANS3D). This file is needed for post-processing.

Invoke DISPLAY III on your computer. The EMRC logo appears on the screen and the programis ready for interactive usage. By default, the menu mode becomes active so that the user can usethe cursor to execute different commands interactively.

To use this manual effectively, we suggest that you get into the command mode and execute thecommands discussed here by typing in from keyboard. After getting comfortable with this procedure, you should experiment with the menu mode and follow similar steps for post- processing results.


8/12/2019 emagtm


8/12/2019 emagtm



14-1

CHAPTER 14

MODELING SESSION 7

The problem of a three dimensional C-shaped magnetic core with an air gap is considered. Theuniform cross-section of the magnetic core is C-shaped and lies in the XY plane. The problemgeometry is shown in Figure 14.0. The excitation in the coil is D C current of current density1.0E+06 Amp/m2 . You have to determine the magnetic vector potential and the resultantmagnetic flux density distribution in the problem region .

0.05

coils

0.065Air

0.04 0.02 Air medium 0.25Air gap

0.020.05

0.25

Figure 14.0 A C-shaped magnetic core excited by the current in the coils

The material property (permeability) of the iron, copper and the air medium surrounding the coreis defined as follows :

Material = IsotropicMUXX (iron) = 400.0 m/HMUXX (air) = 795780.0 m/H

MUXX (copper) = 795780.0 m/H

The C-shaped magnetic core is as shown in Figure 14.0. Hence, a 3D model of the problem isconsidered. The C-shape is horizontal with respect to the X axis and its left bottom corner lies atthe origin of the XY Z coordinate system. It is assumed that the magnetic vector potential Atends to 0 on the boundary shown in Figure 14.0.

8/12/2019 emagtm



14-2

Since the geometry of the C-shaped magnetic core model is in 3D, therefore 3D Hexahedralelement is chosen. NISA offers one of the most complete element libraries among commercialsoftwares, and a list of currently available elements can be found in the User’s manual.

The first step in modeling this problem is to create the geometry of C-shaped magnetic core interms of lines as shown in Figures 14.0. The lines are created by joining grids (points in spacewith predefined coordinates). These lines are used to create surfaces called patches. The patchesare used to create hyperpatches. Once the geometry is obtained in terms of hyperpatches, meshgeneration is used and the mesh is created. Then, excitation (i.e., current density) and the boundary conditions along with material and geometric properties are defined for the elements.Furthermore, analysis and sub analysis types are defined at this stage. Finally, at the end ofmodeling a NISA ASCII file is obtained to perform a Magnetostatic analysis using magneticvector potential.

Invoke DISPLAY III on your computer. When the screen appears click mouse on the COM HOT button ( or hit key ‘c’ on the keyboard ) to get into the command mode. Now enter the followingcommands interactively to generate the model.





GRD,ADD,1,0.0/0.0/0.0 Create grid at the origin of the







GRD,TRS,1T6,B7/1,0.0/0.05/0.0/0,1



GRD,TRS,7T12,B13/1,0.0/0.055/0.0/0,1



GRD,TRS,18,19,0.02/0.0/0.0/0,1Translate grids 18 by 0.02 in the

X direction

GRD,TRS,13,20,-0.02/0.0/0.0/0,1

Translate grids 13 by -0.02 in the

X direction

GRD,TRS,13T20,B21/1,0.0/0.01/0.0/0,1


8/12/2019 emagtm



14-3


GRD,MIR,1T28,B29/1,Y0.125 Mirror grids 1 to 28 about the XZ

plane at Y = 0.125








LIN,2GD,9,10,8 Join grids 9,10 to create line # 8


LIN,2GD,11,12,10 Join grids 11, 12 to create line

#10

LIN,2GD,20,13,11 Join grids 20, 13 to create line #

11


12


13


14


15


16


17

LIN,2GD,28,21,18 Join grids 28, 21 to create line #18


19


20


21


22


23LIN,2GD,26,27,24 Join grids 26, 27 to create line #

24

LIN,MIR,1T24,B27/1,Y0.125 Mirror lines 1 through 24 about XZ

plane at Y = 0.125


# 1


8/12/2019 emagtm



14-4

# 2


# 3


# 4


# 5


# 6


# 7


# 8


# 9


patch # 10


patch # 11


patch # 12


patch # 13


patch # 14


patch # 15


patch # 16PAT,2LN,24,17,17 Use lines 24 and 17 to create

patch # 17


patch # 18


patch # 19


patch # 20


patch # 21

PAT,2LN,48,22,22 Use lines 48 and 22 to createpatch # 22


patch # 23


patch # 24

PAT,MIR,1T17,B25/1,Y0.125 Mirror patches 1 through 17 about

the XZ plane at Y = 0.125

8/12/2019 emagtm



14-5



PAT,LAB,ON Set Patch labels on

PAT,TRS,BRD,B42/1,0.0/0.0/0.07/0,1

Translate patches in BORDER by Z =

0.07 creating patches starting at

numbers 42

ENTITY-IDS: 27

7 8 9 11 12 13 14 15

16 17 18 19 20 21 22 23

24 31 32 33 35 36 37 38

39 40 41

PAT,TRS,BOX,B69/1,0.0/0.0/-0.09/0,1

Translate patches in BOX by Z =

-0.09 creating patches starting at

numbers 69

ENTITY-IDS: 27

42 43 44 45 46 47 48 49

50 51 52 53 54 55 56 57

58 59 60 61 62 63 64 65

66 67 68

PAT,TRS,BOX,B96/1,0.0/0.0/0.05/0,1

Translate patches in BOX by Z =

0.05 creating patches starting at

numbers 96

ENTITY-IDS: 41

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

17 18 19 20 21 22 23 2425 26 27 28 29 30 31 32

33 34 35 36 37 38 39 40

41

HYP,NLIN,0/0/0 Set hypepatch plotting lines as

0/0/0

HYP,2PA,1T41,96T136 Create hyperpatches by using

patches from the set 1 through 41

and set 96 through 136


patches from the set 102 through

104 and set 42 through 44HYP,2PA,106T112,45T51 Create hyperpatches by using


111 and set 45 through 51





8/12/2019 emagtm



14-6






FEG,HEX,1T68,,,2/2/2,104/1//,1.0/1.0/1.0

Mesh patch # 1 through 68 using

E1/E2/E3 as 2/2/2, order as 1,

stiffness type as 102 and material

as 1

MAT,ADD,1,MUXX,400.0,0 For material # 1 (iron) put

permeability value

MAT,ADD,2,MUXX,795780.0,0 For material # 2 (air) put

permeability value

MAT,ADD,3,MUXX,795780.0,0 For material # 3 (copper) put

permeability value

ELE,TRS,BOX,,,.0/.0/-0.07/0,1 Translate elements in BOX by –0.07

in the Z direction

ENTITY-IDS: 216

329 330 331 332 333 334 335 336

337 338 339 340 341 342 343 344

345 346 347 348 349 350 351 352

353 354 355 356 357 358 359 360

361 362 363 364 365 366 367 368

369 370 371 372 373 374 375 376

377 378 379 380 381 382 383 384

385 386 387 388 389 390 391 392

393 394 395 396 397 398 399 400

401 402 403 404 405 406 407 408409 410 411 412 413 414 415 416

417 418 419 420 421 422 423 424

425 426 427 428 429 430 431 432

433 434 435 436 437 438 439 440

441 442 443 444 445 446 447 448

449 450 451 452 453 454 455 456

457 458 459 460 461 462 463 464

465 466 467 468 469 470 471 472

473 474 475 476 477 478 479 480

481 482 483 484 485 486 487 488

489 490 491 492 493 494 495 496497 498 499 500 501 502 503 504

505 506 507 508 509 510 511 512

513 514 515 516 517 518 519 520

521 522 523 524 525 526 527 528

529 530 531 532 533 534 535 536

537 538 539 540 541 542 543 544

VEW,HID,ON Put hidden line on for elements

8/12/2019 emagtm



14-7

ELE,PAI,MAT Paint all elements by material

Number

NOD,CLN Delete all inactive nodes


0.1E-04

Y Type Y


ELE,CMP,ALL,1 Compact all element numbers

ELE,MOD,BRD,MAT,2 Change material properties of

elements in BORDER to material

number 2

ENTITY-IDS: 384

49 50 51 52 53 54 55 56

57 58 59 60 61 62 63 64

65 66 67 68 69 70 71 72

105 106 107 108 109 110 111 112

113 114 115 116 117 118 119 120

129 130 131 132 133 134 135 136

161 162 163 164 165 166 167 168

169 170 171 172 173 174 175 176

177 178 179 180 181 182 183 184

185 186 187 188 189 190 191 192

241 242 243 244 245 246 247 248

249 250 251 252 253 254 255 256

257 258 259 260 261 262 263 264

297 298 299 300 301 302 303 304

305 306 307 308 309 310 311 312

321 322 323 324 325 326 327 328

329 330 331 332 333 334 335 336337 338 339 340 341 342 343 344

345 346 347 348 349 350 351 352

377 378 379 380 381 382 383 384

385 386 387 388 389 390 391 392

401 402 403 404 405 406 407 408

409 410 411 412 413 414 415 416

417 418 419 420 421 422 423 424

425 426 427 428 429 430 431 432

457 458 459 460 461 462 463 464

465 466 467 468 469 470 471 472

473 474 475 476 477 478 479 480481 482 483 484 485 486 487 488

513 514 515 516 517 518 519 520

521 522 523 524 525 526 527 528

537 538 539 540 541 542 543 544

545 546 547 548 549 550 551 552

553 554 555 556 557 558 559 560

561 562 563 564 565 566 567 568

8/12/2019 emagtm



14-8

593 594 595 596 597 598 599 600

601 602 603 604 605 606 607 608

617 618 619 620 621 622 623 624

625 626 627 628 629 630 631 632

633 634 635 636 637 638 639 640

641 642 643 644 645 646 647 648

673 674 675 676 677 678 679 680

681 682 683 684 685 686 687 688

689 690 691 692 693 694 695 696

697 698 699 700 701 702 703 704

729 730 731 732 733 734 735 736

737 738 739 740 741 742 743 744

753 754 755 756 757 758 759 760

ELE,ERA,MAT/2 Erase elements of material no. 2

ELE,MOD,BOX/BOX,MAT,2 Change material properties of

elements in BOX to material

number 2

ENTITY-IDS: 32

393 394 395 396 397 398 399 400

529 530 531 532 533 534 535 536

609 610 611 612 613 614 615 616

745 746 747 748 749 750 751 752

ELE,ERA,MAT/2



number 3

ENTITY-IDS: 144

97 98 99 100 101 102 103 104

153 154 155 156 157 158 159 160289 290 291 292 293 294 295 296

369 370 371 372 373 374 375 376

449 450 451 452 453 454 455 456

505 506 507 508 509 510 511 512

585 586 587 588 589 590 591 592

665 666 667 668 669 670 671 672

721 722 723 724 725 726 727 728

81 82 83 84 85 86 87 88

137 138 139 140 141 142 143 144

273 274 275 276 277 278 279 280

353 354 355 356 357 358 359 360433 434 435 436 437 438 439 440

489 490 491 492 493 494 495 496

569 570 571 572 573 574 575 576

649 650 651 652 653 654 655 656

705 706 707 708 709 710 711 712



8/12/2019 emagtm


8/12/2019 emagtm



14-11

951 958 959 960 961 962 963 964

965 966 967 968 969 970 971 972

979 980 981 982 983 984 985 986

987 992 993 994 995 996 997 998

999 1004 1005 1012 1013 1014 1015 1016

1017 1022 1023 1024 1025 1030 1031 1032

1033 1038 1039 1040 1041 1046 1047 1048

1049 1054 1055 1056 1057 1062 1063 1064

1065 1066 1067 1068 1069 1070 1071 1078

1079 1080 1084 1085 1088 1089 1092 1093

1096 1097 1098 1099 1104 1105 1106 1107

YG

SFP,SIZ,.005 Select symbol size for SPFPOT as

0.05

CRD,ADD,BOX,2,1E6/0/0/0/0, Put current density in X direction

as 1.0E+06 for elements in BOX

ENTITY-IDS: 72

353 354 355 356 357 358 359 360

361 362 363 364 365 366 367 368

369 370 371 372 373 374 375 376

433 434 435 436 437 438 439 440

441 442 443 444 445 446 447 448

449 450 451 452 453 454 455 456

489 490 491 492 493 494 495 496

497 498 499 500 501 502 503 504

505 506 507 508 509 510 511 512

CRD,ADD,BOX,2,-1E6/0/0/0/0, Put current density in X direction

as -1.0E+06 for elements in BOX

ENTITY-IDS: 72569 570 571 572 573 574 575 576

577 578 579 580 581 582 583 584

585 586 587 588 589 590 591 592

649 650 651 652 653 654 655 656

657 658 659 660 661 662 663 664

665 666 667 668 669 670 671 672

705 706 707 708 709 710 711 712

713 714 715 716 717 718 719 720

721 722 723 724 725 726 727 728

CRD,ADD,BOX,2,0/0/1E6/0/0, Put current density in Z direction

as 1.0E+06 for elements in BOXENTITY-IDS: 24

81 82 83 84 85 86 87 88

137 138 139 140 141 142 143 144

273 274 275 276 277 278 279 280

CRD,ADD,BOX,2,0/0/-1E6/0/0, Put current density in X direction

as -1.0E+06 for elements in BOX

ENTITY-IDS: 24

8/12/2019 emagtm


8/12/2019 emagtm



14-13

7,,,, 1.80000E-01, 2.50000E-01, 2.50000E-02, 0

8,,,, 1.80000E-01, 2.25000E-01, 2.50000E-02, 0

9,,,, 1.80000E-01, 2.00000E-01, 2.50000E-02, 0

10,,,, 2.00000E-01, 2.50000E-01, 2.50000E-02, 0

••••••

••••••

••••••

*ELEMENTS

1, 1, 1, 1, 0

1, 2, 5, 4, 7, 8, 11, 10,

2, 1, 1, 1, 0

2, 3, 6, 5, 8, 9, 12, 11,

3, 1, 1, 1, 0

7, 8, 11, 10, 13, 14, 17, 16,

4, 1, 1, 1, 0

8, 9, 12, 11, 14, 15, 18, 17,

5, 1, 1, 1, 0

19, 20, 23, 22, 28, 29, 32, 31,

6, 1, 1, 1, 0

20, 18, 17, 23, 29, 12, 11, 32,

7, 1, 1, 1, 0

22, 23, 26, 25, 31, 32, 35, 34,

8, 1, 1, 1, 0

23, 17, 16, 26, 32, 11, 10, 35,

9, 1, 1, 1, 0

28, 29, 32, 31, 37, 38, 41, 40,

10, 1, 1, 1, 0

29, 12, 11, 32, 38, 6, 5, 41,

••••••

••••••

••••••

*MATEMAG

MUXX, 1,0, 0,400.0,0

MUXX, 2,0, 0,795780.0,0

MUXX, 3,0, 0,795780.0,0

*EMAGCNTL, ID= 1

1,1,1,0.001,1.0

*SPFPOT

** SPFPOT SET = 1

1, 0.00000E+00

2, 0.00000E+00

3, 0.00000E+00

4, 0.00000E+00

8/12/2019 emagtm



14-14

5, 0.00000E+00

6, 0.00000E+00

7, 0.00000E+00

10, 0.00000E+00

13, 0.00000E+00

14, 0.00000E+00

15, 0.00000E+00

16, 0.00000E+00

17, 0.00000E+00

18, 0.00000E+00

19, 0.00000E+00

20, 0.00000E+00

••••••

••••••

••••••

*CURDEN

** CURDEN SET = 1

333,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

334,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

335,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

336,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

337,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

338,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

339,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

340,,,,,

-.200E+08,0.000E+00,0.000E+00,0.000E+00,0.000E+00

••••••

••••••

••••••

*ENDDATA

Now you can run the EMAG solver. For DOS version execute NISA386 and choose ELECTRO-MAG (N); for WINDOWS version run EMAGS; for WORKSTATIONS execute EMAG. AT prompt for the input file name type: ACOR3D.NIS and accept the default ACOR3D.OUT as theoutput file name.

8/12/2019 emagtm



14-15

POST-PROCESSING :

DISPLAY III can now be used to view the results of the analysis graphically. A file namedACOR3D26.DAT is created by the EMAG solver when you run it (remember you had given the

post filename as ACOR3D). This file is needed for post-processing.







REA,POS,acor3d26.dat Read the post processing data

file

CTR,ADD,MVP Select contour as magnetic vector

potential

CTR,CLB,LNUM Select contour plotting as lines

with numbers

VEW,BND,ON Put boundary line plotting for allelements on

SSC,SWI,ON Put switch for solid sections on

SSC,ADD, ,Z0.025 Add a section plane parallel to XY

plane at Z = 0.025


VEW,ANG,1 Change viewing to Angle set 1

CTR,ADD,BRES Select contour as magnetic flux

8/12/2019 emagtm



14-16

density


Figure 14.1 The magnetic vector potential distribution

8/12/2019 emagtm



14-17

Figure 14.2 The magnetic flux density distribution

8/12/2019 emagtm



14-18


8/12/2019 emagtm



15-1

CHAPTER 15

MODELING SESSION 8

The steel plate problem of modeling session 2 is considered here for the HEAT analysis. Heat isgenerated due to current flowing in the steel plate. The boundary of the problem is assumed to beat 0 degrees centigrade at all times. You have to determine the temperature distribution in thesteel plate and the punchout hole.

The material property (for HEAT analysis) of copper, steel and air are defined as follows:

Material = IsotropicKXX (air) = 0.024 W/moCDENS(air) = 1.29 kg/m3

C(air) = 1005.0 J/kgoC

KXX (steel) = 80.0 W/mo

CDENS(steel) = 7000.0 kg/m3

C(steel) = 470.0 J/kgoC

KXX (copper) = 398.0 W/moC

DENS(copper) = 8900.0 kg/m3

C(copper) = 4600.0 J/kgoC

Since the geometry, the finite element mesh etc. of this steel plate model is already created inmodeling session 2 the same is used here. For this use the NISA file DC4E.NIS.

Invoke DISPLAY III on your computer. When the screen appears click mouse on the COM HOT button ( or hit key ‘c’ on the keyboard ) to get into the command mode. Now enter the followingcommands interactively to generate the model.


REA,NIS,DC4E.NIS Read the EMAG NISA file


ELE,PAI,MAT Paint all elements by material

VEW,HID,OFF Put hidden line for elements on

PLO,ALL Plot all entitiesHBC,DEL,BC_DATA Delete all EMAG boundary

conditions

ENTITY-IDS: 100

466000001 12500 466000001 12515 466000001 12530

466000001 12545 466000001 12680 466000001 12695

466000001 12710 466000001 12725 466000001 12860

466000001 12875 466000001 12890 466000001 12905

8/12/2019 emagtm



15-2

466000001 13040 466000001 13055 466000001 13070

466000001 13085 466000001 13220 466000001 13235

466000001 13250 466000001 13265 419000001 3720

419000001 3765 419000001 3810 419000001 3855

419000001 3900 419000001 3945 419000001 18810

419000001 18825 419000001 18840 419000001 18855

419000001 18990 419000001 19005 419000001 19020

419000001 19035 419000001 19170 419000001 19185

419000001 19200 419000001 19215 419000001 19350

419000001 19365 419000001 19380 419000001 19395

419000001 19530 419000001 19545 419000001 19560

419000001 19575 419000001 19710 419000001 19725

419000001 19740 419000001 19755

SPT,ADD,BRD,1,.0, Put Dirichlet boundary condition ,

that is, temperature = 0 at all

nodes inside BORDER

ENTITY-IDS: 280

1 2 3 4 5 6 7 113

114 115 116 117 118 119 120 125

130 135 140 145 154 159 164 169

174 179 180 181 182 183 184 225

226 227 228 229 230 231 232 235

238 241 244 245 246 247 248 249

250 251 254 257 260 263 264 265

266 267 268 269 270 271 272 273

274 275 276 277 278 279 280 281

282 283 284 285 286 287 288 289

290 291 292 293 714 715 716 717

718 719 720 721 722 723 724 725726 727 728 729 730 731 732 733

734 735 736 737 738 739 740 741

742 743 744 745 762 763 764 765

782 783 784 785 802 803 804 805

822 823 824 825 842 843 844 845

878 879 880 881 898 899 900 901

918 919 920 921 938 939 940 941

958 959 960 961 978 979 980 981

982 983 984 985 986 987 988 989

990 991 992 993 994 995 996 997

998 999 1000 1001 1162 1163 1164 11651166 1167 1168 1169 1170 1171 1172 1173

1174 1175 1176 1177 1178 1179 1180 1181

1182 1183 1184 1185 1186 1187 1188 1189

1190 1191 1192 1193 1202 1203 1204 1205

1214 1215 1216 1217 1226 1227 1228 1229

1238 1239 1240 1241 1242 1243 1244 1245

1246 1247 1248 1249 1250 1251 1252 1253

8/12/2019 emagtm



15-3

1254 1255 1256 1257 1258 1259 1260 1261

1262 1263 1264 1265 1266 1267 1268 1269

1278 1279 1280 1281 1290 1291 1292 1293

1302 1303 1304 1305 1314 1315 1316 1317

1318 1319 1320 1321 1322 1323 1324 1325

VEW,LEFT

SPT,ADD,BOX,1,.0, Put Dirichlet boundary condition ,


nodes inside BOX

ENTITY-IDS: 265

269 273 277 281 285 289 293 297

301 305 309 313 317 321 325 329

333 337 341 345 349 353 357 361

365 369 373 377 381 385 389 393

397 401 405 409 413 417 421 425

429 433 437 441 445 449 453 457

461 465 469 473 477 481 485 489

493 497 501 505 509 513 517 521

525 529 533 537 541 545 549 553

557 561 565 569 573 577 581 585

589 593 597 601 605 609 613 617

621 625 629 633 637 641 645 649

653 657 661 665 669 673 677 681

685 689 693 697 701 705 709 713

717 721 725 729 733 737 741 745

749 753 757 761 765 769 773 777

781 785 789 793 797 801 805 809

813 817 821 825 829 833 837 841

845 849 853 857 861 865 869 873877 881 885 889 893 897 901 905

909 913 917 921 925 929 933 937

941 945 949 953 957 961 965 969

973 977 981 985 989 993 997 1001

1005 1009 1013 1017 1021 1025 1029 1033

1037 1041 1045 1049 1053 1057 1061 1065

1069 1073 1077 1081 1085 1089 1093 1097

1101 1105 1109 1113 1117 1121 1125 1129

1133 1137 1141 1145 1149 1153 1157 1161

1165 1169 1173 1177 1181 1185 1189 1193

1197 1201 1205 1209 1213 1217 1221 12251229 1233 1237 1241 1245 1249 1253 1257

1261 1265 1269 1273 1277 1281 1285 1289

1293 1297 1301 1305 1309 1313 1317 1321

1325

YG

SPT,ADD,BOX,1,.0, Put Dirichlet boundary condition,


8/12/2019 emagtm



15-4

nodes inside BOX

ENTITY-IDS: 265

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

17 18 19 20 21 22 23 24

25 26 27 28 29 30 31 32

33 34 35 36 37 38 39 40

41 42 43 44 45 46 47 48

49 50 51 52 53 54 55 56

57 58 59 60 61 62 63 64

65 66 67 68 69 70 71 72

73 74 75 76 77 78 79 80

81 82 83 84 85 86 87 88

89 90 91 92 93 94 95 96

97 98 99 100 101 102 103 104

105 106 107 108 109 110 111 112

113 114 115 116 117 118 119 120

121 122 123 124 125 126 127 128

129 130 131 132 133 134 135 136

137 138 139 140 141 142 143 144

145 146 147 148 149 150 151 152

153 154 155 156 157 158 159 160

161 162 163 164 165 166 167 168

169 170 171 172 173 174 175 176

177 178 179 180 181 182 183 184

185 186 187 188 189 190 191 192

193 194 195 196 197 198 199 200

201 202 203 204 205 206 207 208

209 210 211 212 213 214 215 216217 218 219 220 221 222 223 224

225 226 227 228 229 230 231 232

233 234 235 236 237 238 239 240

241 242 243 244 245 246 247 248

249 250 251 252 253 254 255 256

257 258 259 260 261 262 263 264

265

MAT,DEL,1,ALL Delete all entries of EMAG for

material # 1

MAT,ADD,1,DENS,1.29,0 Put density for material #1

MAT,ADD,1,KXX,.024,0// 0 Put conductivity for material #1MAT,ADD,1,C,1005.0,0// 0 Put specific heat for material #1


material # 2


MAT,ADD,2,KXX,80.0,0// 0 Put conductivity for material #1

MAT,ADD,2,C,470.0,0// 0 Put specific heat for material #1


8/12/2019 emagtm



15-5

material # 3


MAT,ADD,3,KXX,398.0,0// 0 Put conductivity for material #1

MAT,ADD,3,C,4600.0,0// 0 Put specific heat for material #1

NFORM Select NISA DATA GROUP → NISA

FORMS. Then do the following1. Select TRANSIENT HEAT

a. Select HEATCNTL, put number of iterations = 10 and

save it

b. Select TITLE, put the title and save it

c. Select TEMPERATURE HISTORY, put nodes as 3 and enter

455, 615 and 477

d. Select TEMPERATURE POUT, put time steps as 1 and

enter 0.0 as starting time, 250.0 as ending time and

25.0 as time step.

e. Select TIME INTEGRATION, put time step as 25.0 and

maximum time as 250.0

2. Select EXECUTIVE → THEAT ,enter save file as 26 and 39

and enter filename as DC4H

WRI,NIS,dc4h.nis Write NISA file

Now to do coupled heat analysis you have to do some changes in the NISA files for

EMAG and HEAT . Read these files in an ASCII editor and do changes as follows :

1. For NISA file DC4E.NISa. Enter CHEAT = ON after the line SUBA = SCFL

b. Put SAVE = 26,202. For NISA file DC4H.NIS

a. Enter READ DC4E20.DAT after the *SPTEMP cards

The NISA file DC4E.NIS will look as follows :

**EXECUTIVE data deck for EMAG [EMRC NISA]

ANALYSIS = EFIELD

SUBA = SCFL

FILE = dc4e

SAVE=26,20

CHEAT = ON*TITLE

THERMAL ANALYSIS OF STEEL PLATE (EMAG FILE)

*ELTYPE

1, 104, 1

*NODES

1,,,,-6.00000E-02,-2.00000E-02,-4.00000E-03, 0

2,,,,-6.00000E-02,-2.66667E-02,-4.00000E-03, 0

8/12/2019 emagtm



15-6

3,,,,-5.66667E-02,-2.66667E-02,-4.00000E-03, 0

4,,,,-5.66667E-02,-2.00000E-02,-4.00000E-03, 0

5,,,,-6.00000E-02,-2.00000E-02,-2.00000E-03, 0

••••••

•••••• ••••••

*ELEMENTS

1, 3, 1, 1, 0

1, 2, 3, 4, 5, 6, 7, 8,

2, 3, 1, 1, 0

2, 9, 10, 3, 6, 11, 12, 7,

3, 3, 1, 1, 0

9, 13, 14, 10, 11, 15, 16, 12,

4, 3, 1, 1, 0

4, 3, 17, 18, 8, 7, 19, 20,

5, 3, 1, 1, 0

3, 10, 21, 17, 7, 12, 22, 19,

••••••

••••••

••••••

*MATEMAG

**STEEL

SIXX, 1,0, 0,0.1E+07,0

**AIR

SIXX, 2,0, 0,0.1E-14,0

**COPPER

SIXX, 3,0, 0,0.58E+08,0

*EMAGCNTL, ID= 1

1,1,1,0.001,1.0

*SPFPOT

** SPFPOT SET = 1

1, 0.00000E+00

2, 0.00000E+00

5, 0.00000E+00

6, 0.00000E+00

9, 0.00000E+00

11, 0.00000E+00

13, 0.00000E+00

15, 0.00000E+00

••••••

••••••

8/12/2019 emagtm



15-7

••••••

*ENDDATA

The NISA file DC4H.NIS will look as follows :

ANALYSIS = THEAT

FILE = dc4h

SAVE=26

*TITLE

THERMAL ANALYSIS OF STEEL PLATE (HEAT FILE)

*ELTYPE

1, 104, 1

*NODES

1,,,,-6.00000E-02,-2.00000E-02,-4.00000E-03, 0

2,,,,-6.00000E-02,-2.66667E-02,-4.00000E-03, 0

3,,,,-5.66667E-02,-2.66667E-02,-4.00000E-03, 0

4,,,,-5.66667E-02,-2.00000E-02,-4.00000E-03, 0

5,,,,-6.00000E-02,-2.00000E-02,-2.00000E-03, 0

6,,,,-6.00000E-02,-2.66667E-02,-2.00000E-03, 0

7,,,,-5.66667E-02,-2.66667E-02,-2.00000E-03, 0

8,,,,-5.66667E-02,-2.00000E-02,-2.00000E-03, 0

9,,,,-6.00000E-02,-3.33333E-02,-4.00000E-03, 0

10,,,,-5.66667E-02,-3.33333E-02,-4.00000E-03, 0

••••••

••••••

••••••

*ELEMENTS

1, 3, 1, 1, 0

1, 2, 3, 4, 5, 6, 7, 8,

2, 3, 1, 1, 0

2, 9, 10, 3, 6, 11, 12, 7,

3, 3, 1, 1, 0

9, 13, 14, 10, 11, 15, 16, 12,

4, 3, 1, 1, 0

4, 3, 17, 18, 8, 7, 19, 20,

5, 3, 1, 1, 03, 10, 21, 17, 7, 12, 22, 19,

6, 3, 1, 1, 0

10, 14, 23, 21, 12, 16, 24, 22,

7, 3, 1, 1, 0

18, 17, 25, 26, 20, 19, 27, 28,

8, 3, 1, 1, 0

17, 21, 29, 25, 19, 22, 30, 27,

8/12/2019 emagtm


8/12/2019 emagtm



15-9

*TEMPOUT

0.0,250.0,25.0

*ENDDATA

Now you can run the EMAG solver. For DOS version execute NISA386 and choose ELECTRO-MAG (N); for WINDOWS version run EMAGS; for WORKSTATIONS execute EMAG. AT prompt for the input file name type: DC4E.NIS and accept the default DC4E.OUT as the outputfile name. Then you will be asked for the HEAT filename: type DC4H.NIS and DC4H.OUT.

POST-PROCESSING :

DISPLAY III can now be used to view the results of the analysis graphically. Files namedDC4E26.DAT and DC4H26.DAT are created by the EMAG solver when you run it (rememberyou had given these post filenames). These files are needed for post-processing.





You have already seen the post processing results for DC4E26.DAT. For post-processing ofHEAT analysis, type the following commands


REA,POS,dc4h26.dat Read the post processing data

file

CTR,ADD,TEMP Select contour as temperature


with numbers


VEW,ANG1 View plot at viewing angle 1

8/12/2019 emagtm



15-10

VEW,BND,ON Put boundary line plotting for all

elements on


Figure 15.1 The temperature distribution

8/12/2019 emagtm



16-1

CHAPTER 16

MODELING SESSION 9

The problem of two very long (can be considered infinite) parallel plates forming a capacitor isconsidered. This problem is explained in modeling session 3. In this problem infinite elementsare used at the truncated boundary of the problem. You have to determine the electric field andthe voltage distribution in the medium surrounding the two plates.

The material property (permittivity) of the air medium surrounding the two conducting plates isdefined as follows:

Material = IsotropicEXX (air) = 8.85 x 10-12 F/m

The geometry, material, the model and the boundary conditions are explained in modelingsession 3. On the truncated portion of the first quadrant the voltage φ tends to 0 volts in theoutward direction. Infinite elements are placed on this truncated boundary and they replace thefinite elements of session 3.

This is achieved as follows

1. Read the NISA file (say) CAP.NIS in DISPLAY III. Delete the boundary condition φ = 0on the truncated portion of the first quadrant.

2. Replace finite elements on the truncated portion of the first quadrant by infinite elements:at present this cannot be done in DISPLAY III. So you have to enter the infinite element

data in the NISA file using ASCII editor.

Each of these steps are elaborated below:

1. Invoke DISPLAY III on your computer. When the screen appears click mouse on the COMHOT button ( or hit key ‘c’ on the keyboard ) to get into the command mode. Now enter thefollowing commands interactively to generate the model.


REA,NIS,CAP.NIS Read the NISA file of session 3

SET,LABA,OFF Set all labels offPLO,ALL Plot all entities

SFP,PLO,ALL,1T2,8 Plot all Dirichlet boundary

conditions

SFP,DEL,BRD,1T2 Delete Dirichlet boundary

conditions that lie on the

truncated portion of the first

quadrant, that is on the circle.

8/12/2019 emagtm



16-2

ENTITY-IDS: 17

82 83 84 85 86 87 88 89

90 190 191 192 193 194 195 196

197


ELE,FAC,162 Find the faces of elements that

ELE,FAC,165 lie on the truncated portion of

ELE,FAC,65 the first quadrant. Find the face

ELE,FAC,68 that tends to infinity. You will

Find that this face is # 1 for all

elements on truncated portion.


ELE,SRH,BRD Now search all elements that lie

on the truncated portion boundary.

Note these numbers for future use

ENTITY-IDS: 16

65 66 67 68 69 70 71 72

161 162 163 164 165 166 167 168

WRI NIS CAP9.NIS Write the modified NISA file

END Quit DISPLAY III

2.Invoke an ASCII editor. Read file CAP9.NIS, which is an ASCII

file. Now before you commence changes in the file, please note

the format for including infinite elements in your model. At

present you cannot prescribe these elements in DISPLAY III :

so you have to describe them in NISA file according to a

format as shown below :

******************************************************************************

*INFELE data group - Element specified as infinite element and direction of infinity

Applicable analysis types: EFIELD, MFIELD

This data group may be used in all types of analysis: electric field or magnetic field tospecify which elements are infinite, the infinite element type, which faces of the infiniteelement go to infinity and the choice of number of Gaussian points. The data group isvalid for 2D and 3D.

Group ID card: *INFELE

Free format data for a typical infinite element input consists of two card sets

Card set 1 : Element identification card (one card)

Entry No : 1 2 3

8/12/2019 emagtm



16-3

Variable : NELID LASTEL INC

Max Char: 6 6 6entry variable description

1 NELID element number of the infinite element2 LASTEL last element of a range of elements with the same infinite element

description3 INC increment for the range of elements

Card set 2 : The infinite element type, the number of faces, the face numbers of theelement tending to infinity and the number of Gaussian points to be chosenfor Gauss-Laguerre integration scheme , see note 4

Entry No : 1 2 3

Variable : INFTY NFAC FAC1 FAC2 FAC3 NGL

Max Char: 6 6 6 6 6 6

entry variable description

1 INFTY type of the infinite element= 1 - Exponential decay type, see note 1= 2 - Reciprocal decay type, see note 1= 3 - Mapped Element decay type, see note 2

2 NFAC the number of faces of the infinite element tending to infinityspatially, at present a maximum of three is allowed, that is, NFAC = 1, 2 or 3

3 FAC1 face number of the first face tending to infinity, see note 34 FAC2 face number of the second face tending to infinity, see note 35 FAC3 face number of the third face tending to infinity, see note 36 NGL the number of Gaussian points for Gauss-Laguerre integration in any

of the three directions.

Note :1. The Exponential, the Reciprocal and the Mapped type elements are currentlyavailable for:

- NKTP = 102 and 103, NORDR = 1 and NORDR = 2 only

- NKTP = 104 and 105, NORDR = 1 and NORDR = 2 only

2. For any infinite element a maximum of two faces for NKTP = 102 and 103 and threefaces for NKTP = 104 and 105 are allowed to tend to infinity: For one face , enter

8/12/2019 emagtm


8/12/2019 emagtm



16-5

*ELEMENTS

1, 1, 1, 1, 0

1, 10, 11, 2,

2, 1, 1, 1, 0

2, 11, 12, 3,

3, 1, 1, 1, 0

3, 12, 13, 4,

4, 1, 1, 1, 0

4, 13, 14, 5,

5, 1, 1, 1, 0

5, 14, 15, 6,

6, 1, 1, 1, 0

6, 15, 16, 7,

7, 1, 1, 1, 0

7, 16, 17, 8,

8, 1, 1, 1, 0

8, 17, 18, 9,

9, 1, 1, 1, 0

10, 19, 20, 11,

10, 1, 1, 1, 0

11, 20, 21, 12,

•••••••••

•••••••••

•••••••••

*MATEMAG

EXX , 1,0, 0,.8854003E-11,0

*EMAGCNTL, ID= 1

1,1,1,.001,1.0

*SPFPOT

** SPFPOT SET = 1

1, 1.00000E+02

2, 1.00000E+02

3, 1.00000E+02

4, 1.00000E+02

5, 1.00000E+02

6, 1.00000E+02

7, 1.00000E+02

8, 1.00000E+029, 1.00000E+02

73, 0.00000E+00

74, 0.00000E+00

75, 0.00000E+00

76, 0.00000E+00

77, 0.00000E+00

78, 0.00000E+00

8/12/2019 emagtm



16-6

79, 0.00000E+00

80, 0.00000E+00

81, 0.00000E+00

190, 0.00000E+00

198, 0.00000E+00

206, 0.00000E+00

214, 0.00000E+00

222, 0.00000E+00

230, 0.00000E+00

238, 0.00000E+00

246, 0.00000E+00

254, 0.00000E+00

262, 0.00000E+00

270, 0.00000E+00

278, 0.00000E+00

*INFELE

65,,,

3,1,1,0,0,2

66,,,

3,1,1,0,0,2

67,,,

3,1,1,0,0,2

68,,,

3,1,1,0,0,2

69,,,

3,1,1,0,0,2

70,,,

3,1,1,0,0,2

71,,,3,1,1,0,0,2

72,,,

3,1,1,0,0,2

161,,,

3,1,1,0,0,2

162,,,

3,1,1,0,0,2

163,,,

3,1,1,0,0,2

164,,,

3,1,1,0,0,2165,,,

3,1,1,0,0,2

166,,,

3,1,1,0,0,2

167,,,

3,1,1,0,0,2

168,,,

8/12/2019 emagtm



16-7

3,1,1,0,0,2

*ENDDATA

Save the file CAP9.NIS.

Now you can run the EMAG solver. For DOS version execute NISA386 and choose ELECTRO-MAG (N); for WINDOWS version run EMAGS; for WORKSTATIONS execute EMAG. AT prompt for the input file name type: CAP9.NIS and accept the default CAP9.OUT as the outputfile name.

POST-PROCESSING :

DISPLAY III can now be used to view the results of the analysis graphically. A file namedCAP926.DAT is created by the EMAG solver when you run it (remember you had given the postfilename as CAP9). This file is needed for post-processing.







REA,POS,cap926.dat Read the post processing data

file

CTR,ADD,VOLT Select contour as Voltage


with numbers

8/12/2019 emagtm



16-8


DEF,ADD,EFL Select arrow plot as Electric

field

VEW,BND,ON Put boundary line plotting for all

elements on


Figure 16.1 Plot of voltage distribution

8/12/2019 emagtm



16-9

Figure 16.2 Arrow field plot of electric field distribution

8/12/2019 emagtm



emagtm

Documents

Transcript of emagtm