workshop 30b

8/18/2019 Workshop 30b

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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


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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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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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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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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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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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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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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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.

workshop 30b

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