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WORKSHOP 30b
Non-Linear Gap Elements
(using constant displacements)
MSC.Nastran 105 Exercise Workbook 30b-1
Objectives
Model contact of beam with another object using constantdisplacement (SPCD and SPC1).
Find the maximum deflection of the beam.
Submit the file for analysis in NASTRAN.
Find the displacement vectors.
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30b-2 MSC.Nastran 105 Exercise Workbook
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WORKSHOP 30b Non-linear Gap Elements
MSC.Nastran 105 Exercise Workbook 30b-3
Model Description:If we assume that the block is infinitely rigid, then we know that atequilibrium the node at the wall/beam interface (Node 6) will be -0.2 inthe Y-direction. Let us just model it in that way.
Figure 30b.1
Assumptions:•Maximum displacements are at the end of the beam.
•The bar touches the wall and it stays there.
Questions:•Does the beam hit the wall? Yes, we had to assume that it does.
•How can we model the wall? We will model it with constant displacement.
•What is the maximum displacement?
Figure 30b.2 - Grid Coordinates and Element Connectivities
25 in0.2 in 10 in
50 lb
5 in
50 in
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30b-4 MSC.Nastran 105 Exercise Workbook
Figure 30b.3 - Beam Cross Section
Table 30b.1 - Beam Properties
Length 50 in
Height 2 in
Width 1 in
Thickness 0.100 in
Area 0.38 in2
I1 0.229 in4
I2 0.017 in4
0.1 in
0.1 in
0.1 in
1.0 in
1.0 in
2.0 in
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WORKSHOP 30b Non-linear Gap Elements
MSC.Nastran 105 Exercise Workbook 30b-5
Suggested Exercise Steps
Modify Example Problem 30a as follows:
Add contraints (SPCD, SPC1), moving the node -0.2 inchesin the Y-direction.
Prepare for a linear static analysis (SOL 101).
Resubmit for analysis.
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30b-6 MSC.Nastran 105 Exercise Workbook
Exercise Procedure:1. Users who are not utilizing MSC.Patran for generating an input file
should go to Step 6, otherwise, proceed to Step 2.
2. Open database created in Problem 30a named prob30a.db.
3. Activate the entity labels by selecting the Show Labels icon on the tool-bar.
4. Create nodal displacements
File/Open Database
Existing Database Name prob30a
OK
Loads/BCs
Action: Create
Object: Displacement
Type: Nodal
New Set Name wall
Input Data...
Translations < , -0.2, >
Rotations < , , >
OK
Select Application Region...
Geometry Filter FEM
Select Nodes Node 6
Add
OK
Apply
Show Labels
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WORKSHOP 30b Non-linear Gap Elements
MSC.Nastran 105 Exercise Workbook 30b-7
5. Now, you will generate the input file for analysis.
An MSC.Nastran input file called prob30b.bdf will be generated. Theprocess of translating your model into an input file is called ForwardTranslation. The Forward Translation is complete when the Heartbeatturns green. MSC.Patran Users should proceed to Step 7.
Analysis
Action: Analyze
Object: Entire Model
Method Analysis Deck
Job Name prob30b
Solution Type...
Solution Type: LINEAR STATIC
Solution Parameters ...
(Deselect Automatic
Constraints.)
Automatic Contraints
OK
OK
Apply
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30b-8 MSC.Nastran 105 Exercise Workbook
Generating an input file for MSC.Nastran Users:MSC.Nastran users can generate an input file using the data from Table30b.1. The result should be similar to the output below.
6. MSC.Nastran input file: prob30b.dat
SOL 101
TIME 600
CEND
TITLE = Beam and Wall with Wall as constant Displacement
ECHO = NONE
MAXLINES = 999999999
SUBCASE 1
SPC = 1
LOAD = 1
DISPLACEMENT=ALL
BEGIN BULK
PARAM AUTOSPC NO
PARAM INREL 0
PARAM ALTRED NO
PBEAML 1 1 I + A
+ A 2. 1. 1. .1 .1 .1 YES + B
+ B 1. 2. 1. 1. .1 .1 .1
CBEAM 1 1 1 2 0. 1. 0.
CBEAM 2 1 2 3 0. 1. 0.
CBEAM 3 1 3 4 0. 1. 0.
CBEAM 4 1 4 5 0. 1. 0.
CBEAM 5 1 5 6 0. 1. 0.
CBEAM 6 1 6 7 0. 1. 0.
CBEAM 7 1 7 8 0. 1. 0.
CBEAM 8 1 8 9 0. 1. 0.
CBEAM 9 1 9 10 0. 1. 0.
CBEAM 10 1 10 11 0. 1. 0.
MAT1 1 1.+7 .3 .101
GRID 1 0. 0. 0.
GRID 2 5. 0. 0.
GRID 3 10. 0. 0.
GRID 4 15. 0. 0.
GRID 5 20. 0. 0.
GRID 6 25. 0. 0.
GRID 7 30. 0. 0.
GRID 8 35. 0. 0.
GRID 9 40. 0. 0.
GRID 10 45. 0. 0.
GRID 11 50. 0. 0.
SPCD 1 6 2 -.2SPC1 1 123456 1
SPC1 1 2 6
FORCE 1 9 0 50. 0. -1. 0.
ENDDATA
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WORKSHOP 30b Non-linear Gap Elements
MSC.Nastran 105 Exercise Workbook 30b-9
Submit the input file for analysis:
7. Submit the input file to MSC.Nastran for analysis.
7a. To submit the MSC.Patran .bdf file for analysis, find anavailable UNIX shell window. At the command promptenter: nastran prob30b.bdf scr=yes. Monitor the run usingthe UNIX ps command.
7b. To submit the MSC.Nastran .dat file for analysis, find anavailable UNIX shell window. At the command promptenter: nastran prob30b scr=yes. Monitor the run using theUNIX ps command.
8. When the run is completed, edit the prob30b.f06 file and searchfor the word FATAL. If no matches exist, search for the wordWARNING. Determine whether existing WARNINGmessages indicate modeling errors.
9. While still editing prob30b.f06, search for the word:
D I S P (spaces are necessary)
What is the displacement at Node 6?
Displacement at Node 6 = __________inches
What is the maximum displacement?
Maximum Diplacement = __________inches
Comparison of Results
10. Compare the results obtained in the .f06 file with the results onthe following page:
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3 0 b - 1 0
M S C . N a s t r a n1 0 5 E x e r c i s e W or k b o ok
D I S P L A C E M E N T V E C T O R
POINT ID. TYPE T1 T2 T3 R1
1 G 0.0 0.0 0.0 0.0 0.0
2 G 0.0 -9.784728E-03 0.0 0.0 0.0
3 G 0.0 -3.698707E-02 0.0 0.0 0.0
4 G 0.0 -7.929719E-02 0.0 0.0 0.0 5 G 0.0 -1.344040E-01 0.0 0.0 0.0
6 G 0.0 -2.000000E-01 0.0 0.0 0.0
7 G 0.0 -2.737616E-01 0.0 0.0 0.0
8 G 0.0 -3.529739E-01 0.0 0.0 0.0
9 G 0.0 -4.349123E-01 0.0 0.0 0.0
10 G 0.0 -5.169440E-01 0.0 0.0 0.0
11 G 0.0 -5.989757E-01 0.0 0.0 0.0
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WORKSHOP 30b Non-linear Gap Elements
MSC.Nastran 105 Exercise Workbook 30b-11
11. MSC.Nastran Users have finished this exercise. MSC.Patran Usersshould proceed to the next step
12. Proceed with the Reverse Translation process, that is importing theprob30b.op2 results file into MSC.Patran. To do this, return to the Anal- ysis form and proceed as follows:
13. When the translation is complete bring up the Results form.
14. To reset the graphics, click on this icon:
You can go back and select any Results Case, Fringe Results or Deformation Results you are interested in.
Quit MSC.Patran when you are finished with this exercise.
Analysis
Action: Read Output2
Object: Result Entities
Method Translate
Select Results File...
Select Results File prob30b.op2
OK
Apply
Results
Action: Create
Object: Marker
Method: Vector
Select Result Case(s) Default, Static Subcase
Select Vector Result Displacements, Translational
Apply
Reset Graphics
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3 0 b - 1 2 M S C . N a s t r a n 1 0 5 E x e r c i s e W o r k b o o k
Disp. @ Node 6 -0.200 in.
Max. Disp. -0.599 in.