Workshop 30a

WORKSHOP 30a

Non-Linear Gap Elements

MSC.Nastran 105 Exercise Workbook 30a-1

Objectives

■ Model the beam.

■ Find the deflection of the node that is 25 inches from fixed end of the beam.

■ Submit the file for analysis in NASTRAN.

■ Find the displacement vectors.

30a-2 MSC.Nastran 105 Exercise Workbook

WORKSHOP 30a Non-linear Gap Elements


Model Description:A cantilever beam (properties shown in Table 30a.1) hangs over the endof a wall. Initially the beam does not touch the wall. A 50 lb. weight isattached to the beam at some location as shown in Figure 30a.1. What isthe maximum deflection of the beam? Where does it occur? If there is nowall, does the analysis stay the same?

Figure 30a.1

Assumptions:•Maximum displacements are at the end of the beam.•The wall thickness is not important since the deflecting beam will hit its

corner.

Questions:•Does the beam hit the wall?•How can we model the wall?•What is the maximum displacement?

Figure 30a.2 - Grid Coordinates and Element Connectivities

25 in 0.2 in 10 in

50 lb

5 in

50 in


Figure 30a.3 - Beam Cross Section

Table 30a.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



Suggested Exercise Steps

■ Explicitly generate a finite element representation of the beam structure (i.e., the nodes (GRID) and element connectivities (CBEAM) should be defined manually, making sure that one node will be at a location of interest; in this case 25 in. from support and 10 in. from the free end).

■ Define material (MAT1) and element (PBEAML) properties.

■ Apply the fixed boundary constraints (SPC1).

■ Apply load (FORCE).

■ Prepare the model for a linear static analysis (SOL 101).

■ Generate an input file and submit it to the MSC.Nastran solver for linear static analysis.

■ Review the results, specifically determine if the gap of 0.2 in. closes.


Exercise Procedure:1. Users who are not utilizing MSC.Patran for generating an input file

should go to Step 12, otherwise, proceed to Step 2.

2. Create a new database named prob30a.db.

In the New Model Preference form set the following:

3. Activate the entity labels by selecting the Show Labels icon on the tool-bar.

4. Create a curve.

5. Create the finite element model and mesh the surface.

File/New Database

New Database Name prob30a

OK

Tolerance ◆ Default

Analysis Code: MSC/NASTRAN

OK

◆ Geometry

Action: Create

Object: Curve

Method XYZ

Vector Coordinates List <50, 0, 0>

Origin Coordinates List [ 0, 0, 0]

Apply

◆ Finite Elements

Action: Create

Object: Mesh

Show Labels



6. Create nodal displacements.

7. Create a force.

Type: Curve

Global Edge Length 5

Curve List Curve 1

Apply

◆ Loads/BCs

Action: Create

Object: Displacement

Type: Nodal

New Set Name cantilever

Input Data...

Translations <T1 T2 T3> <0 0 0>

Rotations <R1 R2 R3> <0 0 0>

OK

Select Application Region...

Geometry Filter ◆ Geometry

Select Geometry Entities Point 1

Add

OK

Apply

◆ Loads/BCs

Action: Create

Object: Force

Type: Nodal

New Set Name weight


8. Create a set of material properties for the bar.

In the Current Constitutive Models data box, you will see Linear Elastic -[,,,,] - [Active] appear. Click on Cancel to close the form.

9. Define the beam properties.

Input Data...

Force <F1 F2 F3> <0, -50, >

OK

Select Application Region...

Geometry Filter ◆ FEM

Select Nodes Node 9

Add

OK

Apply

◆ Materials

Action: Create

Object: Isotropic

Method: Manual Input

Material Name alum

Input Properties...

Elastic Modulus = 10.0E6

Poisson Ratio = 0.3

Density = 0.101

Apply

Cancel

◆ Properties

Action: Create

Dimension: 1D



Click the beam library icon :

10. Now, you will generate the input file for analysis.

Type: Beam

Property Set Name beam

Option(s): Tapered Section

Input Properties...

Material Name(Select from Material Property Sets box)

m:alum

■ Associate Beam Section

New Section Name ibeam

H 2

W1 1

W2 1

t 0.1

t1 0.1

t2 0.1

OK

Bar Orientation Coord 0.2

OK

Select Members Curve 1

Add

Apply

◆ Analysis


An MSC.Nastran input file called prob30a.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 12.

Action: Analyze

Object: Entire Model

Method Analysis Deck

Job Name prob30a

Solution Type...

Solution Type ◆ LINEAR STATIC

Solution Parameters ...

(Deselect Automatic Constraints.)

❒ Automatic Contraints

OK

OK

Apply



Generating an input file for MSC.Nastran Users:MSC.Nastran users can generate an input file using the data from Table2a.1. The result should be similar to the output below.

11. MSC.Nastran input file: prob30a.dat

SOL 101TIME 600CENDTITLE = Beam Deflection without WallECHO = NONEMAXLINES = 999999999SUBCASE 1 SPC = 1 LOAD = 1 DISPLACEMENT=ALLBEGIN BULKPARAM AUTOSPC NOPARAM INREL 0PARAM ALTRED NOPBEAML 1 1 I + A+ A 2. 1. 1. .1 .1 .1 YES + B+ B 1. 2. 1. 1. .1 .1 .1CBEAM 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 .101GRID 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.SPC1 1 123456 1FORCE 1 9 0 50. 0. -1. 0.ENDDATA


Submit the input file for analysis:

12. Submit the input file to MSC.Nastran for analysis.

12a. To submit the MSC.Patran .bdf file for analysis, find anavailable UNIX shell window. At the command promptenter: nastran prob30a.bdf scr=yes. Monitor the run usingthe UNIX ps command.

12b. To submit the MSC.Nastran .dat file for analysis, find anavailable UNIX shell window. At the command promptenter: nastran prob30a scr=yes. Monitor the run using theUNIX ps command.

13. When the run is completed, edit the prob30a.f06 file and search for the word FATAL. If no matches exist, search for the word WARNING. Determine whether existing WARNING messages indicate modeling errors.

14. While still editing prob30a.f06, search for the word:

D I S P (spaces are necessary)

What is the displacement at Node 6?

Displacement at Node 6 = __________inches

Comparison of Results

15. Compare the results obtained in the .f06 file with the results onthe following page:

WO

RK

SH

OP

30a N

on-linear Gap E

lements

MSC

.Nastran 105 E

xercise Workbook

30a-13

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 R2 R3 1 G 0.0 0.0 0.0 0.0 0.0 0.0 2 G 0.0 -1.081110E-02 0.0 0.0 0.0 -4.089125E-03 3 G 0.0 -4.070478E-02 0.0 0.0 0.0 -7.633033E-03 4 G 0.0 -8.695495E-02 0.0 0.0 0.0 -1.063172E-02 5 G 0.0 -1.468342E-01 0.0 0.0 0.0 -1.308515E-02 6 G 0.0 -2.176190E-01 0.0 0.0 0.0 -1.499342E-02 7 G 0.0 -2.965837E-01 0.0 0.0 0.0 -1.635650E-02 8 G 0.0 -3.809990E-01 0.0 0.0 0.0 -1.717432E-02 9 G 0.0 -4.681404E-01 0.0 0.0 0.0 -1.744693E-02 10 G 0.0 -5.553750E-01 0.0 0.0 0.0 -1.744693E-02 11 G 0.0 -6.426097E-01 0.0 0.0 0.0 -1.744693E-02


16. MSC.Nastran Users have finished this exercise. MSC.Patran Usersshould proceed to the next step.

17. Proceed with the Reverse Translation process, that is importing theprob30a.op2 results file into MSC.Patran. To do this, return to the Anal-ysis form and proceed as follows:

18. When the translation is complete bring up the Results form.

19. To reset the graphics, click on this icon:

You can go back and select any Results Case, Fringe Results orDeformation 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 prob30a.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




Disp. @ Node 6-0.2176 in.

Documents

Workshop 30a