HyperMesh 11.0 LS-DYNA Tutorials

HyperMesh 11.0 TutorialsLS-DYNA Solver Interface

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HyperMesh 11.0 Tutorials - LS-DYNA Solver Interface iAltair Engineering

Proprietary Information of Altair Engineering

HyperMesh 11.0 Tutorials - LS-DYNA Solver Interface

......................................................................................................................................... 1LS-DYNA

........................................................................................................................................ 2HM-4600: General Introduction to HyperMesh - DYNA Interface

........................................................................................................................................ 6HM-4605: Defining LS-DYNA Model and Load Data, Controls, and Output

........................................................................................................................................ 21HM-4610: Using Curves, Beams, Rigid Bodies Joints, and Loads in DYNA

........................................................................................................................................ 41HM-4615: Model Importing, Airbags, Exporting Displayed, and Contacts using DYNA

........................................................................................................................................ 50HM-4620: Rigid Wall, Model Data, Constraints, and Output using DYNA

........................................................................................................................................ 60HM-4625: Assemblies using DYNA

........................................................................................................................................ 85HM-4630: Interfacing for Arbitrary - Lagrangian - Eulerian Capability using DYNA

........................................................................................................................................ 91HM-4635: Checking Penetration, Creating Joints and Checking Minimum Time Step

........................................................................................................................................ 96HM-4640: Dummy Positioning, Seatbelt Routing, and Control Volumes

1 HyperMesh 11.0 Tutorials - LS-DYNA Solver Interface Altair Engineering


LS-DYNA

The following LS-DYNA tutorials are available:

HM-4600: General Introduction to HyperMesh - DYNA Interface

HM-4605: Defining LS-DYNA Model and Load Data, Controls, and Output

HM-4610: Using Curves, Beams, Rigid Bodies Joints, and Loads in DYNA

HM-4615: Model Importing, Airbags, Exporting Displayed, and Contacts using DYNA

HM-4620: Rigid Wall, Model Data, Constraints, and Output using DYNA

HM-4625: Assemblies using DYNA

HM-4630: Interfacing for Arbitrary - Lagrangian - Eulerian Capability using DYNA

HM-4635: Checking Penetration, Creating Joints and Checking Minimum Time Step

HM-4640: Dummy Positioning, Seatbelt Routing, and Control Volumes

Altair Engineering HyperMesh 11.0 Tutorials - LS-DYNA Solver Interface 2


HM-4600: General Introduction to HyperMesh - DYNA Interface

In this tutorial, you will learn to understand the following components of the LS-DYNA interface:

LS-DYNA FE input reader

LS-DYNA FE output template

LS-DYNA Utility Menu

LS-DYNA user profile

Online help for the HyperMesh DYNA interface

HyperMeshs LS-DYNA FE input translator, FE output template, Utility Menu, and user profile sets thefoundation for using LS-Dyna with HyperMesh.

DYNA Utility Menu

The DYNA Utility Menu contains tools specific to using DYNA with HyperMesh. The menu has eight pagesof tools. The pages and some menu tools are described below.

Page Page description

Geom/Mesh Contains a set of macros related to working with model geometry,as well as a set for working with FE mesh.

User For user-defined macros.

Disp HyperMesh entities in several different ways such as: turn thedisplay of individual entity types on and off, isolate only a specificentity type, or turn off the display of everything except entities oftype. Contains a variety of macros that allow you to modify thegraphical display of models.

QA/Model Contains many tools to help you quickly review and clean up thequality of a pre-existing mesh.

Tools in the Tools page of the DYNA Utility Menu

Error check Checks your LS-DYNA deck for potential problems withcomponents, properties, materials, rigids, joints, boundaryconditions, and other entities and reports them on-screen. Thereport identifies the problem entity by ID, describes the error,and then enables you to isolate the entity in the model.

Part Info Summarizes a parts statistics in a dialog.

Name Mapping Provides the ability to change names for various entity types toeither the HyperMesh name or the LS-DYNA name, since both









applications maintain separate names for parts.

Clone Part Clones a given part with the option of duplicating or reusing,section and material properties assigned to the existing part.

Create Part Creates a new part, with the option of either creating new orreusing existing section and material properties through a singlepanel.

Part Replacement Allows you to replace the elements in an existing component(*PART) with new elements; typically replacing a similar partremeshed or slightly reshaped.

Convert To Rigid Converts a portion or whole model to rigid; creates*CONSTRAINED_RIGID_BODIES

Find Free Identifies rigids and welds that have a free end

Find Fix Free Removes free ends of rigids and welds

Fix Incorrect Merges *CONSTRAINED_NODAL_RIGID_BODIES that sharecommon nodes

RLs With Sets *CONSTRAINED_NODAL_RIGID_BODIES in HyperMesh 5.0and older binary files updated to have a *SET_NODE_LIST(entity set). This allows you to have control over the set IDs.

Component Table Summarize, create, and edit parts, sections in the model









Material Table Summarize, create, and edit materials in the model

C-Interfto50 Converts display of DYNA contacts to HyperMesh 5.0 style forDYNA models created from HyperMesh 5.1 Release (noHyperMesh 5.1 DYNA update installed)

Online Help

HyperMesh online help describes how to create every supported DYNA card.

To access the online help do the following:

From the Help menu, click HyperMesh and BatchMesher.

DYNA FE Input Translator

The DYNA FE input translator imports DYNA input files. Three translators exist:

FE input reader Supported DYNA input file

DYNA KEY Version 960, 970 and 971 keyword format

DYNA SEQ Version 936 sequential format

Select an input translator.

To import a DYNA input file click on the Import icon, select the appropriate file and click Import.



DYNA FE Output Template

A DYNA FE output template contains DYNA-specific formatting instructions that HyperMesh uses to createa DYNA input file. Several DYNA templates exist:

FE output template DYNA input file generatedfrom template

Keyword971 Version 971 keyword format



To export an LS-DYNA keyword file click on the Export icon, select the appropriate templatefile, enter the file name and click Export.

DYNA User Profile

To set the user profile, go to the Preferences menu and click User Profiles. Setting the user profile to DYNAsaves you time and does the following:

Sets the FE input reader to DYNA KEY

Loads the dyna.key FE output template

Loads the DYNA Utility Menu

Aligns the graphical user interface to focus on DYNA tools; Re-names and removes certain panels

Enables the ALE Setup panel.

Changing the DYNA user profile to another profile, such as OptiStruct, does not alter the DYNA model.



HM-4605: Defining LS-DYNA Model and Load Data, Controls,and Output

In this tutorial, you will learn to:

View DYNA keywords in HyperMesh as they will appear in the exported DYNA input file

Understand part, material, and section creation and element organization

Create sets

Create velocities

Understand the relation of DYNA entity type to HyperMesh element and load configurations

Create nodal single point constraints

Create contacts with set segment ID

Define output and termination

Export models to LS-DYNA formatted input files

Tools/Utilities

The following tools/utilities set the foundation for settings up an Ls-Dyna input deck with HyperMesh:

LS-Dyna FE input translator

FE output template

Ls-Dyna Utility Menu

User Profile

.

Exercises

This tutorial contains the following exercises:

Exercise 1: Define Model Data for the Head and A-Pillar Impact Analysis

Exercise 2: Define Boundary Conditions and Loads for the Head and A-Pillar Impact Analysis

Exercise 3: Define Termination and Output for the Head and A-Pillar Impact Analysis

Section 1: Define Model Data

Relation of *PART, *ELEMENT, *MAT, and *SECTION to Each Other

*ELEMENT EID PID



*PART PID SID MID

*SECTION SID

*MAT MID

A *PART shares attributes such as section properties (*SECTION) and a material model (*MAT). A group ofelements (*ELEMENT) sharing common attributes generally share a common part ID (PID). The figure belowshows how the keywords *PART, *ELEMENT, *MAT and *SECTION relate to each other. A unique PIDassigns a material ID (MID) and a section ID (SID) to an element.

The figure below shows how the keywords *ELEMENT, *PART, *SECTION, and *MAT are organized inHyperMesh.

*ELEMENT EID PID Elements are organized into a componentcollector

*PART PID SID MID Component collectors card image

*SECTION SID Property collector with a property card image.Assign a property to a *PART by pointing to theproperty collector in the component collectorscard image.

*MAT MID Material collector with a material card image.Assign the material to the *PART by associatingthe material collector to the componentcollector.

Component, property and material collectors are created and edited from the Collectors panel.

View DYNA Keywords in HyperMesh

A HyperMesh card image allows you to view the image of keywords and data lines for defined DYNA entitiesas interpreted by the loaded template. The keywords and data lines appear in the exported DYNA input fileas you see them in the card images. Additionally, for some card images, you can define and edit variousparameters and data items for the corresponding DYNA keyword.

Card images can be viewed using the Card Editor panel which can be accessed from either the Tool menu,the Card Editor icon in the toolbar, or from the right-click context menus in the Model Browser and SolverBrowser.

Create *MAT

In HyperMesh, a *MAT is a material collector with a card image. To relate it to a *PART, the materialcollector is associated to a component collector. A material collector can be created from the ModelBrowser, Solver Browser or by selecting the Material drop down menu and choosing Create.

Update a Components Material

Update any component with any material from the Component Collectors panel, update subpanel.



Material Table Utility

This utility allows you to do the following:

View a list of all existing materials in the model and attributes for them.

Create, edit, merge and check for duplicate materials.

This utility is located in the LS-DYNA Utility tab under DYNA Tools page.

Create *SECTION

In HyperMesh, *SECTION is a property collector with a card image. This is created in the Property Collectors panel, create subpanel.

Exercise 1: Define Model Data for the Head and A-Pillar ImpactAnalysis

The purpose for this exercise is to help you become familiar with defining LS-DYNA materials, sections andparts using HyperMesh.

This exercise comprises of setting up the model data for an LS-DYNA analysis of a hybrid III dummy headimpacting an A-pillar. The head and A-pillar model is depicted below.

Head and A-pillar model

This exercise contains the following tasks.

Define the material *MAT_ELASTIC for the A-pillar part and head part.

Define *SECTION_SHELL for the A-pillar.



Define *SECTION_SOLID for the head.

Define *PART for the A-pillar and the head.

Step 1: Load the LS-DYNA user profile1. From the menu bar , click Preferences > User Profiles.

2. Select the LsDyna profile and click OK.

Step 2: Retrieve the HyperMesh file

1. From the toolbar, click the Open Model icon and browse to the file head_start.hm. 2. Click Open.

The model loads into the graphics area.

Step 3: Define the material *MAT_ELASTIC for the A-pillar and head1. Right click in the Model Browser and pick Create > Material.

The Create material dialog appears.

2. For Name, enter elastic.3. For Card image, select MATL1.

4. Click Card edit material upon creation to activate the option.

5. Click Create to create the material and edit its card image.

6. Click the [Rho] field and enter 1.2 E-6 for the density. 7. For Youngs modulus [E], specify 210.8. For Poissons ratio [Nu], specify 0.26.9. Click return to exit the panel.

Step 4: Define property (*SECTION_SHELL) with a thickness of 3.5 mm for the A-pillar1. Right click in the Model Browser and pick Create > Property.

The Create property dialog appears.

2. For Name, enter section3.5.3. In the Type field, select SURFACE.

4. For Card image, select SectShll.



5. Click Card edit property upon creation to activate the option.

6. Click Create to create the property and edit the card.

7. For T1, enter 3.5.8. Click return to exit the panel.

Step 5: Define *SECTION_SOLID for the head1. Right click in the Model Browser and pick Create > Property.

2. For the Name field, type solid.3. In the Type field, select SURFACE.

4. For Card image, select SectSld.

5. Click Card edit property upon creation to deactivate the option.

6. Click Create to create the property.

Step 6: Define *PART for the A-pillar

MAT_ELASTIC is the material collector named "elastic". *SECTION_SHELL is the property collector named"section3.5".

1. Right click on the pillar component in the Model Browser and pick Edit.

2. For Card image, select Part.

3. Click the Material tab.

4. Click the Assign material option to activate it.

5. For Name, select elastic.

6. Click the Property tab.

7. Click Assign property to activate the option.

8. For Name, select section3.5.

9. Click Update.

Step 7: Define *PART for the head

*MAT_ELASTIC is the material collector named "elastic". *SECTION_SOLID is the property collector named"solid".

1. Right click on the component head in the Model Browser and pick Edit.

2. For Card image, select Part.

3. Click the Material tab.



4. Click the Assign material option to activate it.

5. For Name, select elastic.

6. Click the Property tab.

7. Click the Assign property option to activate it.

8. For Name, select solid.

9. Click Update to update the component.

The exercise is complete. Save your work to a HyperMesh file.

Section 2: Define Boundary Conditions and Loads

*INITIAL_VELOCITY_(Option)

The table below describes DYNA keywords for defining initial velocity.

DYNA keyword Velocity applied to Setup in HyperMesh

*INITIAL_VELOCITY set of nodes,*SET_NODE_LIST

Entity set of nodes, load collector with InitialVel card image

*INITIAL_VELOCITY_GENERATION

one *PART or set of parts,*SET_PART_LIST

Entity set of comps, load collectorwith InitialVel card image

*INITIAL_VELOCITY_NODE individual nodes Created from Velocity panel,organized in load collector with no cardimage

*SET

With the exception of *SET_SEGMENT, all *SET types are created from the Entity Sets panel, from clickingTools > Create > Sets. Graphically view a sets contents with the review function in the Entity Sets panel.*SET_SEGMENT is created from the Contactsurfs panel and is discussed in this chapter.

HyperMesh Entity Configurations and Types

HyperMesh elements and loads have two identifiers: configuration and type. Configuration is a HyperMeshcore feature. Type is defined by the loaded FE output template. A configuration can support multiple types.Before creating elements or loads, select the desired type from either the Elem Types panel.

Use the Load Types subpanel only when creating loads directly on nodes or elements. For all other cases,the load is defined by creating a load collector with a card image. For example, *INITIAL_VELOCITY_NODE(applied directly to nodes) is created from the Velocities panel while *INITIAL_VELOCITY (applied to nodesin a set) is a load collector with the InitialVel card image.

You can see a list of element and load configurations in the Elem Types panel and the Load Types panel,respectively. These panels are pictured below.



elem types panel

load types panel

Some element configurations are rigid and quad4. When a dyna.key template is loaded, types of the rigidconfiguration are RgdBody, ConNode and GenWeld (*CONSTRAINED_NODAL_RIGID_BODY,*CONSTRAINED_NODE_SET and *CONSTRAINED_GENERALIZED_WELD_SPOT).

Similarly, some load configurations are force and pressure. Types of the pressure configuration are ShellPres and SegmentPre (*LOAD_SHELL_ELEMENT and *LOAD_SEGMENT).

Most element and load configurations have their own panels. For example, rigids are created from the Rigidspanel and constraints are created from the Constraints panel.

*BOUNDARY_SPC_(Option)

The table below describes DYNA keywords for defining nodal single point constraints.

DYNA keyword Constraint applied to Setup in HyperMesh

*BOUNDARY_SPC_NODE individual nodes These are constraints created fromthe Constraints panel andorganized into a load collector withno card image.

*BOUNDARY_SPC_SET a set of nodes*SET_NODE_LIST

This is an entity set of nodesreferenced in a load collectors BoundSpcSet card image.

*CONTACT and *SET_SEGMENT

With the exception of *CONTACT_ENTITY, DYNA contacts are created from the Interfaces panel from theBCs menu. (*CONTACT_ENTITY is created from the Rigid Walls panel from the BCs menu.)

A DYNA contact is a HyperMesh group. When you want to manipulate a *CONTACT, such as delete,renumber, or display it off, you select groups.

DYNA Contact Master and Slave Types

DYNA has multiple contact master and slave types from which to choose. The table below lists these types.



While HyperMesh supports all of them, this chapter focuses on contacts with slave and master type 0, setsegment ID. Chapter three focuses on the other slave and master types.

*SET_SEGMENT and Contactsurfs Panel

*SET_SEGMENT is created from the Contactsurfs panel. Additionally, from this panel, you can add andremove elements from an existing *SET_SEGMENT and adjust the normal of segments without adjusting thenormal of elements.

The graphical representation of a contactsurf is pyramids, one pyramid for each segment. The orientation of apyramid represents the normal orientation of the segment. By default, the orientation of a pyramid is thesame as the normal of the element underneath.

A *SET_SEGMENT is specified in a *CONTACT from the Interfaces panel, add subpanel with master: orslave: type set to csurfs.

Exercise 2: Define Boundary Conditions and Loads for theHead and A-Pillar Impact Analysis

The purpose for this exercise is to help you start becoming familiar with defining LS-DYNA boundaryconditions, loads and contacts using HyperMesh.

This exercise comprises of setting up the boundary conditions and loads data for an LS-DYNA analysis of ahybrid III dummy head impacting an A-pillar. The head and A-pillar model is depicted below.


This exercise contains the following three tasks.

Define velocity on all nodes of the head with *INITIAL_VELOCITY



Constrain the pillars end nodes in all six degrees of freedom with *BOUNDARY_SPC_NODE

Define a contact between the head and A-pillar with *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE

Step 1: Make sure the LS-DYNA user profile is still loaded1. From the menu bar, click Preferences > User Profiles.

2. Select LsDyna.

Step 2: Retrieve the HyperMesh file head_2.hm1. Retrieve the model file, head_2.hm. 2. Take a few moments to observe the model using various visual options available in HyperMesh (rotation,

zooming, etc.).

Step 3: Create a node set, *SET_NODE_LIST, containing all the nodes in the headcomponent1. Click Tools > Create > Sets.

2. For Name, enter Vel_Nodes.3. For Card image, select Node.

4. With the nodes selector active, click nodes >> by collector and select the component head.

5. Click create to create the set.

6. Click return to close the panel.

Step 4: Define the velocity1. Right click in the Model Browser and pick Create > Load Collector.

2. For Name, enter init_vel.3. For Card image, select InitialVel.4. Activate the Card edit loadcollector upon creation option if not already activated.

5. Click Create to create the load collector and edit its card image.

6. In the node set ID [NSID] field, select the entity set Vel_Nodes.

7. For the initial velocity in the global x-direction, VX field, specify 5.8. Click return to exit the panel.



Step 5: Create a load collector for the constraints to be created1. Right click in the Model Browser and pick Create > Load Collector.

2. For Name, type SPC.3. For Card image, select none.

4. Optionally select a Color for the load collector.

5. Deactivate the Card edit loadcollector upon creation option.

6. Click Create to create the load collector.

Step 6: Create constraints on the pillars end nodes1. Click BCs > Create > Constraints.

2. Leave the entity selector set to nodes.

3. Click nodes >> by sets and select the pre-defined entity set nodes for SPC.

Notice the nodes at the pillars ends are highlighted.

4. Leave all six degrees of freedom, dof1 thru dof6, active.

5. Set the load type as BoundSPC.

6. Click create to create the constraints.


Step 7: Define a *SET_SEGMENT for the slave entities, the A-pillar elements1. Click BCs > Create > Contact Surfaces.

2. For Name, type pillar_slave.3. For Card image, select setSegment.

4. Optionally select a color for the contactsurf.

5. With the elems selector active, click elems >> by collector and then select the pillar component.

6. Click create to create the contactsurf.

7. Review the contactsurf to make sure its pyramids are pointing out of the pillar.

8. Stay in this panel for the next step.

Step 8: Define a *SET_SEGMENT for the master entities, the head elements1. Select the solid faces subpanel.



2. For Name, type headmaster.3. For Card image, select setSegment.


5. With the elems selector active, click elems >> by collector and then select the head component.

6. Leave the toggle set to nodes on face.

7. Click the yellow nodes selector to make it active.

8. Select three nodes belonging to the same face of a solid element.

9. For the break angle, leave it set to 30.


11. Review the contactsurf to make sure its pyramids are pointing out of the head.


Step 9: Create a HyperMesh group with the SurfaceToSurface card image1. Click BCs > Create > Interfaces.

2. Go to the create subpanel.

3. For Name, type contact.4. For Type, select SurfaceToSurface.

5. Click create to create the group.

6. Stay in the Interfaces panel for the next step.

Step 10: Add the slave and master contactsurfs to the HyperMesh group1. Select the add subpanel.

2. For the master type, select csurfs.

3. Click the contactsurfs selector and select the headmaster contactsurf.

4. Click update in the master: line, to the right of the yellow contactsurfs selector.

5. For the slave type select csurfs.

6. Click the contactsurfs selector in the slave: line and select pillar_slave.

7. Click update in the slave: line.


Step 11: Edit the groups card image to define the AUTOMATIC option



1. Select the card image subpanel.

2. Click edit to edit the groups card image.

3. Under Options, click the toggle to select Automatic.

4. Click return to go back to the Interfaces panel.


Step 12: Review the groups master and slave surfaces1. Select the add subpanel.

2. For name, select contact.

3. Click review.

4. Notice the master and slave entities are temporarily displayed blue and red, respectively.



Section 3: Define Control Cards and Specify Output

*CONTROL and *DATABASE

The *CONTROL cards are optional and can be used to change defaults and activate solution options, suchas mass scaling, adaptive meshing and an implicit solution. It is advisable to define*CONTROL_TERMINATION in a model to specify a jobs end time.

The *DATABASE cards are optional, but are necessary to obtain output files containing results.

In HyperMesh, with the exception of the cards listed in the table below, all *CONTROL and *DATABASEcards are created from the Control Cards panel from either the Setup menu or the Analysis page.

*DATABASE cards NOT created from control cards panel

DYNA card Panel used to create card

*DATABASE_CROSS_SECTION_(Option) PLANE option, Rigid Walls panel

SET option, Interfaces panel

*DATABASE_HISTORY_(Option) Output Blocks panel

*DATABASE_NODAL_FORCE_GROUP Interfaces panel



Exercise 3: Define Termination and Output for the Head and A-Pillar Impact Analysis

The purpose for this exercise is to help you become familiar with defining LS-DYNA control data and outputrequests using HyperMesh.

This exercise comprises of defining the termination and output for an LS-DYNA analysis of a hybrid IIIdummy head impacting an A-pillar. The head and A-pillar model is shown in the image below.


This exercise contains the following four tasks.

Specify the time at which LS-DYNA is to stop the analysis with *CONTROL_TERMINATION

Specify ASCII output with *DATABASE_(Option) cards

Specify the output of d3plot files with *DATABASE_BINARY_D3PLOT

Export the model to an LS-DYNA 970 formatted input file

Step 1: Make sure the LS-DYNA user profile is still loaded

Step 2: Retrieve the HyperMesh file head_3.hm



Step 3: Specify the time at which you want LS-DYNA to stop the analysis with*CONTROL_TERMINATION1. Click Setup > Create > Control Cards to open the Control Cards panel.

2. Click next to scroll through the list.

3. Select CONTROL_TERMINATION.

A card image pops up.

4. For the termination time of the analysis, ENDTIM, specify 2.5.5. Click return to go back to the Control Cards panel.

Step 4: Specify the output of d3plot files with *DATABASE_BINARY_D3PLOT1. Click next to scroll through the list and go to the next page if necessary.

2. Select DATABASE_BINARY_D3PLOT.

3. For the interval between outputs in the D3PLOT file, [DT] field, specify 0.1.4. Click return to go back to the Control Cards panel.

Step 5: Specify ASCII output with *DATABASE_(Option) cards1. Click next to scroll through the list and go to the next page.

2. Select DATABASE_OPTION.

3. For the GLSTAT file, [GLSTAT] field, specify 0.1.

This specifies the output of global data at every 0.1 ms.

4. For the MATSUM file, [MATSUM] field, specify 0.1.

This specifies the output of material energies every 0.1 ms.

5. For the SPCFORC file, [SPCFORC] field, specify 0.1.

This specifies the output of SPC reaction forces every 0.1 ms.

6. Click return to go back to the Control Cards panel.


Step 6: Export the model as an Ls-Dyna keyword file1. Click File > Export > Solver Deck to open the Export tab.

2. Make sure Ls-Dyna is selected as the File type and the appropriate template is selected.



3. Enter the file name as head_complete.key.4. Click Export.

Step 7 (Optional): Submit the LS-DYNA input file to LS-DYNA 9701. From the desktops Start menu, open the LS-DYNA Manager program.

2. From the solvers menu, select Start LS-DYNA analysis.

3. Load the file head_complete.key. 4. Click OK to start the analysis.

Step 8 (Optional): Post-process the LS-DYNA results using HyperView




HM-4610: Using Curves, Beams, Rigid Bodies Joints, andLoads in DYNA

In this tutorial, you will learn how to:

Create XY curves to define non-linear materials

Define beam elements with HyperBeam

Create constrained nodal rigid bodies

Create joints

Define *DEFORMABLE_TO_RIGID

Define *LOAD_BODY

Define *BOUNDARY_PRESCRIBED_MOTION_NODE

Use the HyperMesh Component Table tool to review the models data

Tools

The following tools are covered in this tutorial:

DYNA Tools

Component Table

Curve Editor

The Dyna Tools menu can be accessed from the Utility Menu.

The Component Table is part of the DYNA Tools menu. With this tool, you can view a summary of themodels parts as well as create and edit parts. Below is a list of the tool's functionality.

Create a list of displayed or all parts and view them in the graphics area

Display parts with same section or material

Rename and renumber parts, sections and materials

Update thickness

Create new parts

Assign sections and materials to parts

Export table to file with comma separated format

In the Component Table window, place the cursor over each button to see an explanation of each button.

Below is a sample image of the Component Table.



The Curve Editor can be accessed by clicking XYPlots > Curve Editor from the menu bar.

The Curve Editor is a pop-up window that allows you to view and modify graphed curves in a more intuitiveand holistic way than the individual xy plots panels provide.

Below is a list of the tools functionality.

Change curve attributes

Change graph attributes

Display curves in the graph area

Create a new curve

Delete a new curve

Rename a curve

Below is a sample image of the Curve Editor.



Exercises

This tutorial contains the following exercises:

Exercise 1: Define Model Data for Seat Impact Analysis

Exercise 2: Define Boundary Conditions and Loads for the Seat Impact Analysis

Process

This section describes how to define model data.

*DEFINE_CURVE

The *DEFINE_CURVE card defines a curve in LS-DYNA. Curves are often used to define non-linear materialsand loads. There are a few methods for creating DYNA curves in LS-DYNA in HyperMesh. A few methods aredescribed below.

Method 1: Create using the Curve Editor

From the menu bar, click XYPlots > Curve Editor.



Method 2: Input XY Data from a File

Create *DEFINE_CURVE by inputting an XY data file from the Read Curves or Edit Curves panel in the xyplots menu. The figure below displays a sample XY data file with a format supported by these panels.

XYDATA,

x1 y1

x2 y2

ENDDATA

XYDATA,

x1 y1

x2 y2

ENDDATA

XY Data File Format

Engineers often receive test data in Excel file format. Data exported from Excel in comma or space delimitedformat can be read into HyperView. Data exported from HyperView in XY data format can be read intoHyperMesh to create curves. In HyperView, from the Plot client, select Export Curves from the File menu.Select the XY Data format from the pop-up window.

Method 3: Create with Math Expressions

Create *DEFINE_CURVE with math expressions from the Edit Curves panel. From this panel, you can alsocreate *DEFINE_CURVE with a math expression and an XY data file combination.

Plots

The HyperMesh naming convention for curves is curveN where N is a number. Curves are displayed in plots.Turn a curve's display on and off by turning it's plot display on and off from the Display panel in the ModelBrowser.

Export Only XY Curves

Export only curves to a LS-DYNA input file using one of the following templates. Click File > Export... andselect Custom as the File type. Choose Curves.key as the template file.

HyperMesh template DYNA input file generated from template

ls-dyna\curves.key Version 970 keyword format for curves only



ls-dyna960\curves.key Version 960 keyword format for curves only

These templates are in the folder ALTAIR_HOME\templates\feoutput. Import the exported file intoHyperMesh from the using the Import tab.

*DEFINE_TABLE

*DEFINE_TABLE defines a table. It consists of a *DEFINE_TABLE card followed by n lines of input. Each ofthe n additional lines define a numerical value in ascending order corresponding to a *DEFINE_CURVE inputwhich follows the *DEFINE_TABLE command and the related input.

In HyperMesh, *DEFINE_TABLE is created from a dummy *DEFINE_CURVE. Create a dummy curve usingthe method explained above. Edit the dummy curve from the Card Edit panel. In the pop-up card imageactivate the DEFINE_TABLE option to create *DEFINE_TABLE and specify values and load curves. Thefigure below shows the *DEFINE_TABLE card image.

If, for example, ten stress-strain curves for ten different strain rates are given, HyperMesh will write ten cardsto the DYNA input file after the first card for *DEFINE_TABLE. The ten corresponding *DEFINE_CURVEspecifications will immediately follow in the exported input file.

Beam Elements

*ELEMENT_BEAM is created from the Bars panel. In this panel, you need to always specify node 3, whichdetermines the initial configuration of the cross section. However, not every beam type requires node 3. Youcan suppress node 3 by card editing the beam elements from the Card Editor panel.

Beam elements are organized into a component collector with the Part card image. Specify the THICKNESSand PID options by card editing the beam elements from the Card Editor panel.

*SECTION_BEAM

*SECTION_BEAM is a property collector.

HyperBeam



HyperBeam supports *SECTION_BEAM when ELFORM is 2 or 3. The HyperBeam panel is located in the1D page. HyperBeam allows you to create a beam cross-section entity and this is saved to the HyperMeshdatabase as a beamsec. Select a beamsec from the *SECTION_BEAM card image to populate its fields A,

Iss, Itt, and Irr. The cross-section can also be seen graphically using the tool bar options and .

Nodal Rigid Bodies

*CONSTRAINED_NODAL_RIGID_BODY can be created by clicking Tools > Create Cards from the menubar, or by clicking Mesh > Create > 1D Elements > Rigids. Below is an image of the Rigids panel. Whenthe panel option attach nodes as set is active, a *SET_NODE_LIST (entity set) containing all of the selectednodes is created. You can renumber the entity set from the Renumbers panel. In the exported DYNA inputfile, the *SET_NODE_LIST immediately follows the *CONSTRAINED_NODAL_RIGID_BODY card.

Rigids panel

Joints

All DYNA joints are created by clicking Tools > Create Cards, or by clicking Mesh > Create > 1D Elements> Joints. They are organized into a component collector with no card image.

Unlike other 1D elements, you do not specify the DYNA joint type from the Elem Types panel. Rather,specify it in the panel used to create it, the FE Joints panel.

The FE Joints panel has the property= selector. As a DYNA user, you can disregard this selector. If theHyperMesh user profile is loaded, the panel also has the orientation option. As a DYNA user, you candisregard this option also.

Coincident Node Picking

For DYNA joints, the nodal points in the nodal pairs should coincide in the initial configuration. The coincident picking option can be turned on by clicking Preferences > Graphics. It allows you to graphicallyselect a desired node from a stack of coincident nodes. This option also supports coincident picking forelements, loads, and systems.

Create Coincident Nodes

Create a node "like" an existing node from the Nodes panel in the Geom page. Select the type in sub-panel.Click as node, select a node in the graphics area and then click create.

*CONSTRAINED_JOINT_STIFFNESS

*CONSTRAINED_JOINT_STIFFNESS_OPTION is a HyperMesh property collector with the JointStff card



image.

*DEFORMABLE_TO_RIGID

The table below lists the DYNA *DEFORMABLE_TO_RIGID keywords.

DYNA keyword Purpose

*DEFORMABLE_TO_RIGID Switch parts to rigid at the start of the calculation

*DEFORMABLE_TO_RIGID_AUTOMATIC Switch parts to rigid or to deformable at some state inthe calculation

*DEFORMABLE_TO_RIGID_INERTIA Define inertial properties for the new rigid bodiescreated when the deformable parts are switched

Below is the card format for specifying parts for these keywords:

1 2 3 4 5 6 7 8

PID MRB

PID is the ID of the slave part to be switched

MRB is the part ID of the master rigid body to which the part is merged. This field exists only for*DEFORMABLE_TO_RIGID and for *DEFORMABLE_TO_RIGID_AUTOMATIC when the partis to be switched to rigid.

In HyperMesh, rather than specify one part at a time, you specify an entity set containing all of the desiredslave parts. On export, the entity sets part IDs are written to the DYNA input file according to the above cardformat.

Exercise 1: Define Model Data for the Seat Impact Analysis

This exercise will help you continue to become familiar with defining LS-DYNA model data usingHyperMesh.

This exercise is comprised of defining and reviewing model data for an LS-DYNA analysis of a vehicle seatimpacting a rigid block. The seat and block model is shown in the image below.



Seat and block model

Step 1: Load the LS-DYNA user profile1. Click Preferences > User Profiles, or click the User Profiles icon.

2. Select LsDyna.

Step 2: Retrieve the HyperMesh file 1. Browse to the file seat_start.hm. 2. Take a few moments to observe the model using various visual options available in HyperMesh (rotation,

zooming, etc.).

Step 3: Create an xy plot1. Click XY Plots > Create > Plots to open the Plots panel.

2. For plot=, enter seat_mat.3. Verify the plot type is set to standard.

4. Leave the like = field empty.

When an existing plot is selected, the new plot adopts its attributes.

5. Click create plot.

6. Click return.



Step 4: Input data from a file to create two stress-strain curves1. Click XYPlots > Create > Curves > Read Curves to access the Read Curves panel.

2. For plot =, leave it set to seat_mat.3. Click browse... and locate the file named seat_mat_data.txt.4. Click input to input the file.

5. Notice two curves are created and are named 0.001 strain rate for steel (curve1) and 0.004 strain ratefor steel (curve2).

6. Click return.

Step 5: Create a dummy xy curve to be used to create *DEFINE_TABLE1. Click XYPlots > Edit > Curves to access the Edit Curves panel.

2. Go to the create subpanel.

3. For plot =, select seat_mat.

4. Activate the math option.

5. In the x = field enter {0.0, 0.2}.6. In the y = field enter {0.4, 0.4}.7. Click create to create the curve.

8. Notice the curve is displayed in the seat_mat plot and has the name curve3.


Step 6: Create *DEFINE_TABLE from the dummy curve1. Right click on curve3 in the Model Browser and pick Card Edit.

2. Activate the option DEFINE_TABLE.

3. In the card image, in the [ArrayCount] field, specify 2.

This is the number of strain rate values to be specified.

4. For the strain rate VALUE(1) field, specify 0.001.5. For the strain rate VALUE(2) field, specify 0.004.6. Click on CurveId(1) and select curve1.

7. Click on CurveId(2) and select curve2.

8. Click return to exit the panel.



Step 7: Create the non-linear material (*MAT_PIECEWISE_LINEAR_PLASTICITY)1. Click View > Browsers > HyperMesh > Solver to open the Solver Browser.

2. Right-click anywhere in the Solver Browser and click Create > *MAT > MAT (1-50) > 24-*MAT_PIECEWISE_LINEAR_PLASTICITY.

3. For Name: type steel and click OK.

Notice *MAT_PIECEWISE_LINEAR_PLASTICITY card is created.

4. For density [Rho] field, specify 7.8 E-6.5. For Youngs Modulus [E] field, specify 200.6. For Poissons ratio [NU] field, specify 0.3.7. For yield stress [SIGY] field, specify 0.25.8. For the *DEFINE_TABLE id [LCSS] field, select curve3 (id=5).

9. Click return to close the card image.

Step 8: Update the base_frame and back_frame components with the new non-linear material1. Click Tools > Component Table.

2. From the Table menu, click Editable.

3. Select the components base_frame by clicking on its row to highlight it.

4. For Assign Values:, select Material name.

5. For HM-Mats:, select steel.

6. Click Set and click Yes to confirm.

7. Repeat steps 3 - 6 for the component back_frame.

8. Close the Component Table.

Steps 9-11: Create a beam element, *ELEMENT_BEAM, to completethe seats back_frame connection to the side_frame on the left side

Step 9: Restore a pre-defined view 1. In the Model Browser open the Views folder.

2. Click next to Beam_view to see the beam view.



Step 10: Set the current component to beams

1. In the Model Browser, right-click on the beams component and select Make Current to set the beamcomponent as the current collector.

Step 11: Create the beam1. Click Mesh > Create > 1D Elements > Bars to open the panel.

2. Click the leftmost switch and select node.

A direction node is selected later to define the beams section orientation.

3. Click the Node A selector to make it active.

4. Select the center node of the left nodal rigid body for Node A.

Node B is active now.

5. Select the center node of the right nodal rigid body for Node B.

6. Select any non-center node of one of the nodal rigid bodies for the direction node.

7. Notice the beam is created.


Step 12: Display node IDs for ease of following the next steps

1. Click on the numbers icon to open the Numbers panel.

2. Change the entity selector set to nodes.

3. Click nodes and select by id. Enter 425-427, 431 and press Enter.4. Activate the display checkbox, and click on to display the IDs.

5. Click return.

Step 13: Set the current component to welding

1. In the Model Browser, right-click on the welding component and select Make Current to set thewelding component as the current collector.

Step 14: Select the RgdBody type for the HyperMesh rigid configuration1. Click Mesh > Assign > Element Type.

2. Click on rigid = select RgdBody.



3. Click return.

Step 15: Create the nodal rigid body (*CONSTRAINED_NODAL_RIGID_BODY)1. Click Mesh > Create > 1D Elements > Rigids.

2. Set nodes 2-n to multiple nodes.

3. Select the beams free end for node1.

4. Select nodes 425, 426, 427 and 431 for nodes 2-n.

5. Leave the attach nodes as set option active.

6. Click create to create the nodal rigid body.

7. Click return.

A *CONSTRAINED_JOINT_STIFFNESS is not created; it is not needed for this joint to work.

Step 16: Display node IDs for ease of following the next steps

1. Click on the numbers icon to open the Numbers panel.

2. Leave the entity selector set to nodes.

3. Click nodes and select by id. Type 1635, 1636 and press Enter.4. Activate the display checkbox, and click on to display the IDs.

5. Click return.

6. From the toolbar, click the Wireframe Elements (Skin Only) icon to change to standard graphicsmode.

Step 17: Activate coincident picking1. Click Preferences > Graphics.

2. Activate coincident picking.

3. Click return.

Step 18: Set the current component to joint

1. In the Model Browser, right-click on the joint component and select Make Current to set it as thecurrent collector.

Step 19: Create a revolute joint between two nodal rigid bodies



(*CONSTRAINED_JOINT_REVOLUTE)

The rigid bodies must share a common edge along which to define the joint. This edge, however, must nothave the nodes merged together. The two rigid bodies will rotate relative to each other along the axis definedby the common edge.

1. Right-click in the Solver Browser and pick Create > *CONSTRAINED >*CONSTRAINED_JOINT_REVOLUTE.

2. Set the joint type to revolute.

node1 is active.

3. Click on node 1635.

Notice the coincident picking mechanism displays two nodes 1635 and 1633.

4. Move the mouse to node 1635 in the coincident picking display and click on it to select it for node 1 inrigid body A.

node2 is now active.

5. Click on node 1635 again to see the coincident picking mechanism and select node 1633 for node 2 inrigid body B.


6. Click on node 1636.

Two coincident nodes are displayed 1636 and 1634

7. Select node 1636 for node 3 in rigid body A.


8. Select node 1634 for node 4 in rigid body B.

9. Click create to create the joint.

10. Click return.

Steps 20-22: Define *DEFORMABLE_TO_RIGID to set up the movingseat as rigid until the time of impact with the block, to reducecomputation time

Step 20: Create an entity set that contains the components base_frame,back_frame, and cover1. Click Tools > Create > Sets.

2. For name =, enter set_part_seat.3. For card image, select Part



Notice the entity selector is set to comps.

4. Click the yellow comps button and select the base_frame, back_frame and cover components.


6. Click return.

Step 21: Define *DEFORMABLE_TO_RIGID to switch the deformable seat to rigid atthe beginning of the analysis1. Right click in the Solver Browser and pick Create > *DEFORMABLE_TO_RIGID >

*DEFORMABLE_TO_RIGID.

2. For Name:, enter dtor and click OK to create the card.3. Click the part set ID, [PSID] button twice and select set_part_seat.

4. Click the master rigid body, [MRB], button twice and select back_frame.

5. Click return.

Step 22: Create *DEFORMABLE_TO_RIGID_AUTOMATIC to switch the rigid seat todeformable when contact between the seat and block is detected1. Right click in the Solver Browser and pick Create > *DEFORMABLE_TO_RIGID >

*DEFORMABLE_TO_RIGID_AUTOMATIC.

2. For Name:, type dtor_automatic and click OK to create the card.3. For the unique set number for this automatic switch set, [SWSET], enter 1.4. For the activation switch code [CODE] select 0.

The switch will take place at [TIME1].

5. For [TIME1] enter 175.

The switch will not take place before this time.

6. Activate R2D_Flag in the menu area.

On export, the number of rigid parts to be switched to deformable is written to the R2D field (card 2, field6). This number is based on the number of parts in the entity set you select next.

7. Move the scroll bar on the left side of the card image down to see [PSIDR2D].

8. Click the [PSIDR2D] button twice and select set_part_seat.

9. Click return.

Steps 23-27: Review the models component data using the ModelBrowser, Solver Browser or Component Table tool



Using the Model Browser approach:

Step 23: Display only parts with a particular material (Ex: steel)

1. In the Model Browser, click on the Material View icon .

2. Highlight the material steel, then right click on it and choose isolate to see only components that havethe selected material assigned.

3. To review several materials, click on the isolate icon then select a material and scroll through thematerial using the arrow keys in the model browser. The corresponding parts are automatically isolatedin the view.

4. Follow the above steps to select components using the By Properties option.

Step 24: Display all components

1. In the Model Browser, click on the Material View icon .

Step 25: Rename a part

1. In the Model Browser, click on the Component View icon .

2. Select the part to rename and right click on it. Choose rename from the extended menu options and thebecomes editable to enter a new name.

Notice the part's new name in the Solver and Model Browser.

Step 26: Renumber a part ID1. In the Model Browser, right-click on the Part ID field.

2. Enter a number that does not conflict with the existing part IDs.

3. Click Yes to confirm.

Using the Solver Browser approach:


1. Expand the Materials folder to see all available materials in the model.

2. Right-click on the material Steel and select Isolate from the menu.

3. Complete steps 1 and 2 to select components based on properties using the *section folder.




1. In the Solver Browser, click on the Material View icon .


1. In the Solver Browser, click on the Component View icon .

2. Select the part to rename and right click on it. Choose rename from the extended menu options and thebecomes editable to enter a new name.


Step 26: Renumber a part ID1. In the Model Browser, right-click on the Part ID field.

2. Enter a number that does not conflict with the existing part IDs.


Using the Component Table approach:


1. Click Tools > Component Table.

2. From the Display menu, click By Material.

3. Select material steel and click proceed.

Notice that the GUI and the Component Table show only those components with material steelassigned. All other components get turned off.

5. Follow the above steps to select components using the By Properties and By thickness option.


1. From the Display menu, click All.

2. Notice now that the GUI shows all components of the model.


1. From the Table menu, click Editable to make the table editable. (All columns with a white background



can be edited. Ex: Part name, Part id, Thickness etc.)

2. Click on any part name field to edit it.



Step 26: Renumber a part ID

1. Click on the Part Id field.

2. Type a number that does not conflict with the existing part IDs.



Step 27: Review the models data using the Solver Browser

The created solver entities are listed in the corresponding folder in Solver Browser. Each entity has thefollowing options Show, Hide, Isolate, and Review to help user navigate through the model

1. Select dtor in the *DEFORMABLE_TO_RIGID folder

2. Right-click and choose Isolate to show only the entities that are referred in this keyword.

3. Right click and choose Review to highlight the entities.

4. Select the folder *BOUNDARY, right-click and select Show. The entities on which the loads in the folderare defined are displayed, as well as the load handles.

Exercise 2: Define Boundary Conditions and Loads for theSeat Impact Analysis

This exercise will help you continue to become familiar with defining LS-DYNA boundary conditions andloads using HyperMesh.

In this exercise, you will define boundary conditions and load data for an LS-DYNA analysis of a vehicle seatimpacting a rigid block. The seat and block model is shown in the image below.



Seat and block model

This exercise contains the following three tasks.

Define gravity acting in the negative z-direction with *LOAD_BODY_Z

Define the seats acceleration with *BOUNDARY_PRESCRIBED_MOTION_NODE

Export the model to an LS-DYNA 970 formatted input file and submit it to LS-DYNA

Step 1: Make sure the LS-DYNA user profile is still loaded

1. Click Preferences > User Profiles, or click the User Profiles icon.

2. Select LsDyna.

Step 2: Retrieve the HyperMesh file

1. Retrieve the model file, seat_2.hm.

2. Take a few moments to observe the model using various visual options available in HyperMesh (rotation,zooming, etc.).

Step 3: Define gravity acting in the negative z-direction with *LOAD_BODY_Z1. Right click in the Solver Browser and pick Create > LOAD> *LOAD_BODY_Z.

2. For Name:, enter gravity.3. Click OK to create the card.



4. Click on the load curve LCID field twice and select the curve named gravity curve.

5. For the load curve scale factor [SF], specify 0.001.6. Click return.

Steps 4-6: Define the seats acceleration with*BOUNDARY_PRESCRIBED_MOTION_NODE

Step 4: Create a load collector for the acceleration loads to be created

1. Right click in the Model Browser and pick Create > Load Collector.

2. For Name:, type accel.

3. For Card image:, select none.

4. Optionally, select a Color for the load collector.

5. Click create to create the load collector.

6. Click return.

Step 5: Create acceleration loads on nodes1. Click BCs > Create > Accelerations.

2. Set the load types = field to PrcrbAcc.

3. With the nodes selector active, select nodes and select by sets.

4. Select the pre-defined entity set accel_nodes.

5. Change the method to curve, vectors.

6. For magnitude, specify 0.001.

This is the scale factor for the pre-defined curve to be specified in the next step for the accelerationloads. It will define the seats acceleration as a function of time.

7. For the direction selector, select x-axis.

This is the x-translational degree of freedom.

8. Click the yellow curve button and select acceleration curve.

9. For the magnitude% =, specify 1.0E+7.

This is the scale factor for the graphical representation of the acceleration loads. It does not affect theactual acceleration value.

10. Click create to create the acceleration loads.

11. Click return.



Step 6: Export the model to an LS-DYNA 971 formatted input file

1. Click File > Export > Solver Deck.

2. Make sure the template field shows Ls-Dyna.

3. Enter the File name: as seat_complete.key.

4. Click Export.

Step 7 (Optional): Submit the LS-DYNA input file to LS-DYNA 971

1. From the Start menu on your desktop, open the LS-DYNA Manager program.


3. Load the file seat_complete.key.

4. Click OK to start the analysis.

Step 8 (Optional): View the results in HyperView

The exercise is complete. Save your work as a HyperMesh file.



HM-4615: Model Importing, Airbags, Exporting Displayed, andContacts using DYNA


Define *AIRBAG_WANG_NEFSKE for the airbag mesh geometry

Define an initial velocity of 3 mm/ms in the negative x-direction for the head with*INITIAL_VELOCITY_GENERATION

Define a contact between the airbag and head with*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE

Define *CONTACT_AIRBAG_SINGLE_SURFACE for the airbag

Define a contact between the plate and the airbag with *CONTACT_NODES_TO_SURFACE

Import a DYNA model

Warning and Error Messages

On import of a DYNA model, any HyperMesh warning and error messages are written to a file named dynakey.msg or dynaseq.msg, depending on the FE input translator used. This file is created in thesame folder from which HyperMesh is started.

Unsupported Cards

On import, the few DYNA cards not supported by HyperMesh are written to the unsupp_cards panel. Thispanel can be accessed from the menu bar by clicking Setup > Create > Control Cards. The unsupportedcards are exported with the remaining model.

Care should be taken if an unsupported card points to an entity in HyperMesh. An example of this is anunsupported material referenced by a *PART. HyperMesh stores unsupported cards as text and does notconsider pointers.

LSTC Dummy Files

You can read LSTC Hybrid III dummy files into HyperMesh by first converting the tree file to FTSS/ARUP treefile format.

Include Files

HyperMesh supports *INCLUDE. From the menu bar, click File > Import. Use the options to merge,preserve or skip include files. When include files are read, HyperMesh maintains the IDs of non-existingentities and does not use these IDs for new entities.

Export Displayed

From the Export tab, you can select the Displayed option to export only displayed nodes and elements.Only model data associated to the displayed nodes and elements are exported. This model data includesmaterials and their associated curves, properties, portions of contacts, and output requests.



Create and Review Contacts

The table below describes how all slave and master set types are created and specified in contacts.

Slave and master settype

DYNA card Panel used to create card Equivalent type in Interfaces panel, addsubpanel

EQ. 0: set segment id *SET_SEGMENT set_segment (contactsurfs)or

csurfs

Interfaces, add subpanel entity

EQ. 1: shell element set id *SET_SHELL_Option Entity Sets or sets


EQ. 2: part set id *SET_PART_LIST Entity Sets or sets

Interfaces, add subpanel comps

EQ. 3: part id *PART Collectors comps

* EQ. 4: node set id *SET_NODE_Option Entity Sets or sets


* EQ. 5: include all Interfaces, add subpanel all

* EQ. 6: part set id forexempted parts

*SET_PART_LIST Interfaces, add subpanel andthen card image sub-panel

sets

* For slave surface only

Add subpanel

While the Interfaces panel, add subpanel has several master and slave types - comps, sets, entity, etc. -to choose from in order to specify the DYNA master or slave set for a *CONTACT, only the valid master andslave types are selectable for the particular contact you are creating.

When the master or slave type is set to comps and only one component is selected, the DYNA type is 3,part ID, and *PART is created. When multiple components are selected, the DYNA type is 2, part set ID, and*SET_PART_LIST is created.

When the master or slave type is set to sets, only those sets valid for the particular contact you arecreating are selectable. For example, for *CONTACT_NODES_TO_SURFACE, only a list of node sets isavailable for slave; you will not see a list of other set types, like element or part sets.



Review Contacts

You can review contacts with the review button in the Interfaces, add subpanel.

Exercise: Define Airbag, Velocity, and Contacts for the AirbagAnalysis

This exercise will help you become familiar with defining LS-DYNA airbags using HyperMesh. It will also helpyou continue to learn how to define LS-DYNA loads and contacts using HyperMesh.

In this exercise, you will define an airbag, velocity, and contacts for an LS-DYNA analysis of a headimpacting an inflating airbag. The head and airbag model is shown in the image below.

Head and airbag model

Step 1: Load the LS-DYNA user profile1. Click Preferences > User Profiles.

2. Select LsDyna.

Step 2: Import the LS-DYNA model1. From the menu bar, File > Import > Solver Deck.

2. In the File: field, browse to the file airbag_start.key.



3. Click Import.

Steps 3-5: Define *AIRBAG_WANG_NEFSKE for the airbag meshgeometry

Step 3: Create a set of parts, *SET_PART_LIST, containing the AirbagFront andAirbagRear components1. Click Tools > Create > Sets.

2. For name =, type airbag_set.3. For card image, select Part.

4. Click on comps and select the components AirbagFront and AirbagRear.



Step 4: Define the airbag (*AIRBAG_WANG_NEFSKE)1. Click View > Browsers > HyperMesh > Solver to open the Solver Browser.

2. Right click in the Solver Browser and pick Create >.*AIRBAG > *AIRBAG_WANG_NEFSKE.

3. For Name:, type airbag and click OK to create the card.4. Click return to open the Control Volumes panel.

5. Click the set selector button and select the entity set airbag_set. The parts in this set define theairbags geometry.

6. Click update.

7. Click edit to edit card image of the control volume.

8. Enter the following data in the card image.

Field Value Parameter description

CV 1023. 0 Heat capacity at constant volume

CP 1320. 0 Heat capacity at constant pressure

T 780. 0 Temperature of input gas

LCMT cur ve i d 1 Load curve specifying input mass flow rate

C23 1. 0 Vent orifice coefficient



LCA23 cur ve i d 2 Load curve defining vent orifice area as a function ofpressure

CP23 1. 0 Orifice coefficient for leakage

PE 1. 0E- 4 Ambient pressure

RO 1. 0E- 9 Ambient density

GC 1. 0 Gravitational conversion constant

9. Click return twice to close the card image and then close the panel.

Step 5: Define an initial velocity of 3 mm/ms in the negative x-direction for the headwith *INITIAL_VELOCITY_GENERATION1. Right click in the Solver Browser and pick Create > *INITIAL > *INITIAL_VELOCITY_GENERATION.

2. For Name:, type velocity and click OK to close the dialog.3. In the card image, under STYP, switch the toggle to select Part ID for the set type.

4. Click the PID button twice to select the Head component.

5. For velocity in the X direction VX field, specify 3.6. Click return to go back to the main menu.

Steps 6-12: Define a contact between the airbag and head with*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE

Step 6: Create a HyperMesh group with the card image SurfaceToSurface1. Right click in the Solver Browser and pick Create > *CONTACT > CONTACT (A-O) >

*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE.

2. For Name: type Airbag_Head and click OK to create the card.3. Click return to go back to the Interfaces panel.

Step 7: Specify the head to be the master surface with surface type 3, part ID1. Select the add subpanel.

2. Set the master surface type to comps.

3. Click comps and select the Head component.

4. Click update for the master selection.



5. Stay in the add subpanel for the next step.

Step 8: Specify all of the airbag to be the slave surface with surface type 2, part setID1. Set the slave surface type to sets.

2. Click sets and select the pre-defined entity set airbag_set (*SET_PART_LIST).

This set contains the AirbagFront and AirbagRear components.

3. Click update in the slave line to update the slave selection.


Step 9: View the master and slave entities1. Click review.

2. Notice the master and slave entities are temporarily displayed blue and red, respectively. All otherentities are temporarily displayed grey.


Step 10: Define *CONTACT_AIRBAG_SINGLE_SURFACE for the airbag1. Right click in the Solver Browser and pick Create > *CONTACT > CONTACT (A-O) >

*CONTACT_AIRBAG_SINGLE_SURFACE.

2. For Name, type airbag and click OK to create the card.3. Click return to go back to the Interfaces panel.


Step 11: Define all of the airbag to be the slave surface with slave set type 2, partset ID1. Select the add subpanel.

2. Set the slave: surface type to sets.

3. Click sets and select the pre-defined entity set airbag_set (*SET_PART_LIST).

4. Click update to update the slave selection.


Step 12: View the slave entities



1. Click review.

2. Notice the slave entities are temporarily displayed red. All other entities are temporarily displayed grey.


Steps 13- 18: Define a contact between the plate and the airbag with*CONTACT_NODES_TO_SURFACE

Step 13: Due to the dynamics of the contact, define the AirbagRear component tobe the master surface with master type 0, set segment ID1. Click BCs > Create > Contact Surfaces.

2. Select the elems subpanel.

3. For name=, enter AirbagRear_master.4. For card image =, select setSegment.


6. With the elems selector active, select elems and select by collector.

7. Select the AirbagRear component.


9. Notice the contactsurfs pyramids point into the airbag. They should point out. In the next step you willreverse their direction.

10. Stay in this panel for the next step.

Step 14: Reverse the contactsurfs pyramids so they point out of the airbag1. Select the adjust normals subpanel.

2. With the contactsurf button active, select AirbagRear_master.

3. Toggle from by elems to all elems.

4. Click reverse normals.


Step 15: Create *CONTACT_NODES_TO_SURFACE card1. Right click in the Solver Browser and pick Create >.*CONTACT > CONTACT(A-O) >

*CONTACT_NODES_TO_SURFACE.

2. For Name:, type Airbag_Plate and click OK.





Step 16: Specify the AirbagRear_master contactsurf for the contacts mastersurface1. Select the add subpanel.

2. Set the master surface type to csurfs.

3. Click the contactsurfs button and select AirbagRear_master.

4. Click update to update the master selection.


Step 17: Define the plate to be the contacts slave surface with slave type 4, nodeset ID1. Set the slave surface type to entity.

2. Click nodes and select by collector.

3. Select the RigidPlate component.

4. Click add to add the slave selection.


Step 18: View the master and slave entities1. Click review.

2. Notice the master and slave entities are temporarily displayed blue and red, respectively. All otherentities are temporarily displayed grey.

3. Click return to go back to the main menu.

Step 19: Review the created solver entities using the Solver Browser1. Click on the plus sign next to the *contact folder in the Solver Browser to expand it. Expand the sub-

folders as well.

2. Under *CONTACT_AIRBAG_SINGLE_SURFACE, right-click on Airbag and select Review. The slaveentities become highlighted in red and the master entities become highlighted in blue. Right-click againand select Reset Review to return to regular display.

3. Right-click on Airbag_Plate and select Isolate. Only the entities that are part of this contact aredisplayed.

4. Right-click on Airbag again and select Show. The entire airbag is displayed in the screen, as this entity



contains the entire airbag.

5. Expand the *INITIAL folders, right-click on velocity and choose Show from the menu. The entities onwhich the load has been defined will appear (in this case it is head).

Step 20: Export the model to an LS-DYNA 971 formatted input file

1. Click on Export and select the icon Export Solver Deck .

2. Notice File type is set to LsDyna. It is automatically selected since you are in LsDyna user profile.

3. Set Template to Keyword971.

4. Click the Select file icon to select the path and enter the file name as airbag_complete.key.5. Under Export options, set Export: to All.

6. Click Export.

Step 21 (Optional): Submit the LS-DYNA input file to LS-DYNA 970

1. From the Start menu, open the LS-DYNA Manager program.


3. Load the file airbag_complete.key.

4. Click OK to start the analysis.

Step 22 (Optional): View the results in HyperView




HM-4620: Rigid Wall, Model Data, Constraints, and Outputusing DYNA


Create *PART_INERTIA for the component vehicle mass to partially take into account the inertiaproperties and mass of the missing parts.

Create velocity on all nodes but the barrier nodes with *DEFINE_BOX and *INITIAL_VELOCITY.

Make the closest row of nodes of the crash boxes a part of the vehicle mass rigid body with*CONSTRAINED_EXTRA_NODES.

Create a contact between the crash boxes, the bumper and the barrier with*CONTACT_AUTOMATIC_GENERAL.

Specify the output of resultant forces for a plane on the left interior and exterior crash boxes with*DATABASE_CROSS_SECTION_PLANE.

Create a stationary rigid wall to constrain further movement of the barrier after impact with*RIGIDWALL_PLANAR_FINITE.

Specify some nodes to be output to the ASCII NODOUT file with *DATABASE_HISTORY_NODE.

*PART_INERTIA

The INERTIA option allows inertial properties and initial conditions to be defined rather than calculated fromthe finite element mesh. This applies to rigid bodies only.

When importing a DYNA model into HyperMesh, the *PART_INERTIA IRCS parameter value is changed from0 to 1. (The inertia components are changed from global to local axis.) This allows inertia components to beautomatically updated when *PART_INERTIA elements are translated or rotated. When selecting*PART_INERTIA elements to translate or rotate, select elements by comp. This selection method ensuresthe inertia properties are automatically updated.

*CONSTRAINED_EXTRA_NODES

This card defines extra nodes to be part of a rigid body. In HyperMesh, it is created from the SolverBrowser.

*DATABASE_CROSS_SECTION_(Option)

*DATABASE_CROSS_SECTION_(Option) defines a cross section for resultant forces written to the ASCIISECFORC file. The options are PLANE and SET.

For the PLANE option, a cutting plane must be defined. For best results, the plane should cleanly passthrough the middle of the elements, distributing them equally on either side.

The SET option requires the equivalent of the automatically generated input via the cutting plane to beidentified manually and defined in sets. All nodes in the cross-section and their related elements contributingto the cross-sectional force resultants should be defined in sets.

*DATABASE_CROSS_SECTION_SET and *DATABASE_CROSS_SECTION_PLANE are created from the



Solver Browser. Like the Interfaces panel, anything created from the Rigid Walls panel is a HyperMeshgroup. Thus, to rename, renumber or delete a *DATABASE_CROSS_SECTION card, select groups from the Rename, Renumber or Delete panel.

*RIGIDWALL

A *RIGIDWALL provides a method for treating contact between a rigid surface and nodal points of adeformable body.

In HyperMesh, *RIGIDWALL keyword cards are created from the Solver Browser.

Exercise: Set Up the Bumper Model for Impact AnalysisThis exercise will help you become familiar with defining LS-DYNA rigid walls using HyperMesh. It will alsohelp you continue to learn how to define LS-DYNA model data, constraints, and output using HyperMesh.

In this exercise, you will define model data, loads, constraints, a rigid wall, and output for an LS-DYNAanalysis of a bumper in a 40% frontal offset crash. The bumper model is shown in the image below.

Bumper model

Step 1: Load the LS-DYNA user profile

1. On the Preferences menu, click User Profiles or click the User Profile icon.

2. Select LsDyna.



Step 2: Import the LS-DYNA model bumper_start.key1. Click File > Import > Solver Deck.

2. In the File: field, browse to the file bumper_start.key.3. Click Import.

Step 3: Define *PART_INERTIA for the vehicle mass component to partially takeinto account the inertia properties and mass of the missing parts1. Right click on vehicle mass in the Model Browser and click Card Edit.

2. Click the switch under Options and select Inertia.

3. For the center of mass coordinates XC enter 700.4. In the YC field, enter 0.5. In the ZC field, enter 170. 6. For translational mass TM, specify 800.7. For the components of the inertia tensor, specify the following:

IXX IXY IXZ IYY IYZ IZZ

1.5E+07 -5.0E+03 -8.0E+06 5.0E+07 -900 6.0E+07

8. For the initial translational velocity along the X-axis, VTX, specify -10.9. Click return to exit the panel.

Step 4: Create a *DEFINE_BOX that contains all nodes but the barrier nodes1. Right click in the Solver Browser and pick Create > *DEFINE > *DEFINE_BOX.

2. In the name= field, type box velocity.3. Make sure card image= is set to DefineBox.

4. Optionally select a color.

5. Toggle lower bound from corner node to x=, y=, z=.

6. Specify the lower and upper bounds as follows:

lower bound upper bound

X= -530 200



Y= -800 800

Z= 0 300

7. Click create to create the box.


Step 5: Create initial velocity on all nodes but the barrier nodes1. Right click in the Solver Browser and pick Create >*INITIAL > *INITIAL_VELOCITY.

2. For Name, type velocity and click OK to create the card.3. For the initial velocity in the global X direction, VX, specify 10.4. Click on the BOXID field and select the box velocity option.


Note: You can also create velocity boundary condition on a set of nodes by clicking the load collector

icon in the tool bar and picking Initialvel as the card image.

Step 6: View the closest nodes which are in the pre-defined node entity set(*SET_NODES_LIST) named Constrain Vehicle1. Click Tools > Edit > Sets.

2. Click review.

3. Toggle from display RLs to hide RLs.

This filters all nodal rigid body sets from the list.

4. Select the Constrain Vehicle set.

Notice the sets nodes are highlighted.


Step 7: Create *CONSTRAINED_EXTRA_NODES_SET1. Right click in the Solver Browser and pick Create > *CONSTRAINED >

*CONSTRAINED_EXTRA_NODES_SET.

2. In the Name field, type ExtraNodes and click OK to create the card.3. Click the part ID (PID) field to activate it, and then select it again. Select the vehicle mass component.

This is the rigid body to which the nodes will be added. The ID is automatically entered into the card.





Step 8: Define the nodes in the Constrain Vehicle set to be a part of the vehiclemass rigid body1. Select the add subpanel.

2. Make sure name=, is set to ExtraNodes.

3. Set the slave type to sets.

4. Click on sets and select the Constrain Vehicle set.

5. Click select.

6. Click update to update the slave selection.


Note: You can also create extra node set on a set of nodes by clicking BCs > Create > Interfaces withthe Type field set to Xtranode.

Step 9: View the extra nodes that are a part of the vehicle mass rigid body1. Click review.

Notice the extra nodes are temporarily displayed red while the PID (vehicle mass) is temporarilydisplayed blue. All other entities are temporarily displayed grey.


Step 10: Create an entity set, *SET_PART_LIST, for just the vehicle masscomponent

All other components not in this set will be included in the contact.

1. Right click in th

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