Fixed Plate Modeling and Modal analysis By ANSYS
-
Upload
mohammad-ahmad-gharaibeh -
Category
Documents
-
view
274 -
download
4
Transcript of Fixed Plate Modeling and Modal analysis By ANSYS
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
1/55
1
Constrained Plate Natural Frequencies andMode Shapes using ANSYS Modal analysis
Mohammad A Gharaibeh11/19/2014
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
2/55
Goal
This Lecture aims to obtain natural frequencies and mode shapesof a constrained isotropic plate using ANSYS Software
2
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
3/55
Problem Description
3
Problem:
Obtain natural frequencies and mode shapes ofsquared isotropic plate with fixed boundaryconditions using ANSYS Modal analysis
Material Parameter SI units English units
Youngs modulus 73.1 GPa 10.6 MSI
Density 2780 Kg/m3 2.6*10-4 lb.sec2/in4
Poissons ratio 0.3 0.3
Be careful of this!!
Material: Aluminum
Geometry Parameter SI units (m) English units (inch)
Length (a) 0.3 12
Width (b) 0.3 12Thickness (h) 6.35*10-3 0.25
Plate Size:
We will useEnglish units
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
4/55
ANSYS Environment
4
Utility Menu: File controls, plotting, selecting parameters, etc.Input line:Allows you to type in commands directlyToolbar: Used to open and save ANSYS jobs.Main Menu:The place you will use a lot. Preprocessing, Solution and Postprocessing
Graphics window:
Where the model,Postprocessing andresults will appear.
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
5/55
Start modeling - Preprocessing
In this step we will learn how:
Define Element Type.
Specify Material Parameters
Build the Model
Mesh
5
Element type defines the way how do you want to mesh your model. In FEA, it dependson the problem type and it is very necessary to be selected carefully.
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
6/55
Define Element Type
6
Main Menu:
Preprocessor >> Element Type >> Add/Edit/Delete
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
7/55
Define Element Type (contd)
7
Element type window: Add
Library of Element type: Solid >> Brick 8 Node 185This is SOLID185 elementsuitable for various 3-D modeling of solid structures
12
3
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
8/55
Define Element Type - Keyoption
8
We need to specify little more details for this element to make match our desired problem
using element KEYOPTIONElement types window: OptionsSOLID185 element type options: Element technology (K2) >> Simple enhanced Strain
1
3
2
You can testother optionsavailable andcompare withtheoreticalresults
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
9/55
Specify Material Properties - 1
9
Now we need to input material properties
Main Menu: Preprocessor >> Material Props >> Material Models
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
10/55
Specify Material Properties - 2
10
From Window appears
Material Model Number 1 >> Structural >> Linear >> Elastic >> IsotropicThen Type in your values for Youngs Modulus and Poissons ratio >> OK
1 2,3,4,5
6
10.6e6equals to10.6 MSI
Take care ofyour units!
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
11/55
Specify Material Properties - 3
11
Specify density
Material Model Number 1 >> Structural >> DensityThen Type in your value for Density>> OKClose window (X)
Take care ofyour units!
2.6e-4 equalsto 2.6*10-41
23
5
4
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
12/55
Build Geometry - 1
12
Main Menu: Preprocessor >> Modeling >> Create >>Volumes >> Block >> By dimensions
Type in your plate dimensions in x,yand zcoordinates and hit OK.Other Modeling procedure ??Try keypoints, lines, areas and end up with volume
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
13/55
Build Geometry - 2
13
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
14/55
Meshing
14
Meshing is the most essential step in FEA modeling. It means that use the element type you
specified to fill in (mesh) your solid model with nodes and elements.
ImportantYou need nodes and elements for the finite element solution NOT just the
solid model weve just created. The solid model does NOT participate in the FEA solution.
It requires three steps:
Attribute element type and material properties to the solid model
Mesh Controlspecify number of divisions. Meshing the solid model (create elements and nodes)
Solid Model FEA Model
Meshing
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
15/55
15
Main Menu: Preprocessor >> Meshing >> Mesh Attributes >>Picked volumes
Click on the Solid model
Meshing: 1- Attribution
Click on thesolid model
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
16/55
16
Main Menu: Preprocessor >> Meshing >> Mesh Attributes >>Picked volumes
When you click on the solid model its color will turn into Purple
Now, hit OK
Meshing: 1- Attribution
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
17/55
17
Main Menu: Preprocessor >> Meshing >> Mesh Attributes >>Picked volumes
Volume attributes window: OK
Here we specify which material and/or element type to use. In our case, it should look like:
Meshing: 1- Attribution
18
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
18/55
18
In order to specify number of divisions, we need first to observe the LINES
Utility Menu: Plot >> Lines
Meshing: 2- Mesh Control
19
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
19/55
19
In order to specify number of divisions, we need first to observe the LINES
Utility Menu: Plot >> Lines
Meshing: 2- Mesh Control
20
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
20/55
20
In order to specify number of divisions, we need first to observe the LINES and lines NUMBERS
Utility Menu: PlotCtrls >> Numbering
Meshing: 2- Mesh Control
21
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
21/55
21
In order to specify number of divisions, we need first to observe the LINES and lines NUMBERS
Plot Number Controls window: LINE >> ON
Hit OK
Meshing: 2- Mesh Control
Turn this ON
22
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
22/55
22
Meshing: 2- Mesh ControlTo changes the angle of view use Dynamic Model Mode
Or simple using keyboard and mousePress and hold Ctrl + Mouse right clickFor zoomMouse scroll
23
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
23/55
23
Meshing: 2- Mesh ControlAfter plotting lines and numbers we need now to divide them
Main Menu: Preprocessor >> Meshing >> Size Cntrls >> Picked LinesThen, click on the desired lines. In our case just select the in-plane 8 lines (top and bottom) of plate.Hit OK
24
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
24/55
24
Meshing: 2- Mesh ControlAfter plotting lines and numbers we need now to divide them
Element size on Picked Lines window: NDIV type in 50 (or any other number of divisions)OK
25
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
25/55
25
Meshing: 3- Mesh CreationTo create mesh (elements and nodes)
Main Menu: Preprocessor >> Meshing >> Mesh >> Volumes >> Mapped >> 4 to 6 sidedClick on the model (as done previously) >> Hit OK
To plot volumes:
Utility Menu: Plot>> Volumes
26
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
26/55
26
Meshing: 3- Mesh CreationThe FEA Model
27
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
27/55
Constraint application
Applying constraint involves two steps:
Select required nodes based on the problem specifications 0.25 at corners
Add constraintsin our case all directions (all DOF).
27
1 2
34
28
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
28/55
Constraint applicationnode selection
28
Utility Menu: Select >> Entities
29
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
29/55
Constraint applicationnode selection
29
Utility Menu: Select >> Entities
30
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
30/55
Constraint application
corner 1 nodes selection
30
1select nodes atthe bottom of theplate
2reselect nodes atrequired location inx-direction
3reselect nodes atrequired location iny-direction
x
y
x
z
Top view
Side view
Bottom of the platez =0
31
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
31/55
pply constraintsMain Menu: Solution >> Define Loads >> Apply >> Structural >> Displacement >>On NodesPick All
32
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
32/55
pply constraintsIn the Box appearsAll DOFValue = 0
33
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
33/55
pply constraintsIn the Box appearsAll DOFValue = 0
34
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
34/55
Constraint applicationcorner 2 node selection
To select corner 2 nodes - similarly
Utility Menu: Select >> Entities
x
y
35
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
35/55
Constraint application
corner 1 nodes selection
1select nodes atthe bottom of theplate
2reselect nodes atrequired location inx-direction
3reselect nodes atrequired location iny-direction
x
y
x
z Side view
Bottom of the platez =0
Top view
36
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
36/55
pply constraintsMain Menu: Solution >> Define Loads >> Apply >> Structural >> Displacement >>On NodesPick All
37
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
37/55
pply constraintsIn the Box appearsAll DOFValue = 0
38
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
38/55
pply constraints
39
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
39/55
Apply Constraints
Similar procedure can be followed to constrain corner 3 andcorner 4.
1 2
34
40
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
40/55
Four corners constraints
41
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
41/55
Solution of the FE model
After applying constraints (Boundary conditions) on the FEmodel, it is ready for solution.
As we have done last week:
Define analysis typeModal analysis.
Solve
42
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
42/55
Solution: 1- Define analysis typeTo define the analysis type (which is here model analysis)Main Menu: Solution >> Analysis Type >> New AnalysisSelect Modal and OK
43
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
43/55
Solution: 1- Define analysis typeMore analysis optionsMain Menu: Solution >> Analysis Type >> Analysis OptionsSolver: Block LanczosNumber of Modes: 20 (or else)Hit OK
Make sure to have
same number
44
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
44/55
Solution: 1- Define analysis typeMore analysis optionsMain Menu: Solution >> Analysis Type >> Analysis OptionsSpecify frequency range that youd like to look in (make sure to be large enough)
45
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
45/55
Solution: 2- Solve the FE modelSolutionMain Menu: Solution >> Solve >> Current LS (Load Step)OK
46
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
46/55
Solution: 2- Solve the FE modelSolution is DONE!Life is Good!Hit OK and close /Status window.
47
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
47/55
Postprocessing step
As discussed previously ANSYS has three main analysis step:
Preprocessing
Solution
Postprocessing
DONE!
In PostProcessing step: List Natural Frequencies Select mode shape you want to see Plot it!
We are here!
DONE!
48
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
48/55
Postprocessing: 1- List Natural FrequenciesGeneral Postprocessor: Results summaryA list of natural frequencies will appear
49
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
49/55
Postprocessing: 1- List Natural FrequenciesIf you want to save natural frequencies as an ASCII fileFile >> Save
Units here are in Hz!
50
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
50/55
Postprocessing: 2- Select mode shape neededTo select which mode shape to observeMain Menu: General Postproc. >> Read results >> By load step
LSTEP = 1, SBSTEP = 1 >> OK
First Mode shape
51
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
51/55
Postprocessing: 3- Plot mode shapeTo plot mode shapeMain Menu: General Postproc. >> Plot results >> Contour Plot >> Nodal SolutionFrom tree >> DOF Solution >> Displacement vector SUMOK
First Mode shape
52
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
52/55
Postprocessing: 3- Plot mode shapeFirst Mode shape
53
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
53/55
Postprocessing: Animate a mode shape
Utility Menu: PlotCtrls >> Animate>> Mode Shape
54
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
54/55
Postprocessing: Animate a mode shapeSpecify number of frames and delay time.Display type >> DOF Solution >> TranslationUSUM
OK
55
-
8/10/2019 Fixed Plate Modeling and Modal analysis By ANSYS
55/55
Do you want your log file?Main Menu: Session Editor
Everything youve
done is here