WORKSHOP 13c

MSC.Nastran 105 Exercise Workbook 13c-1

Load Analysis of a Beam (using a Rigid Bar)

Objectives:n Account for a beam offset using a rigid connection.

n Prepare a MSC.Nastran input file for a linear static analysis.

n Review analysis results.

n Recover element forces.

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13c-2 MSC.Nastran 105 Exercise Workbook

MSC.Nastran 105 Exercise Workbook 13c-3

WORKSHOP 13c Load Analysis of a Beam

Model Description: Part C (using a RBAR)A third way to model the beam is to create a node off the center ofthe beam cross section and attach it to the beam with a rigidconnection. By applying the load at the new load, a moment will beinduced on the beam through the rigid connection. Table 13c.1 listthe material properties for the model. Table 13c.2 lists thedimensions for the beam cross section.

Figure 13c.1 - Loads and Boundary Conditions

Table 13c.1 - Material Properties

Elastic Modulus = 10E6 lb/in2

Poissons Ratio = 0.3

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13c-4 MSC.Nastran 105 Exercise Workbook

Table 13c.2 - Element Properties

Beam Dimensions

H 4.0 in.

W1 2.0 in.

W2 2.0 in.

t 0.1 in.

t1 0.15 in.

t2 0.15 in.

MSC.Nastran 105 Exercise Workbook 13c-5

WORKSHOP 13c Load Analysis of a Beam

Suggested Exercise Steps:

n Modify lesson 13a as follows:

n Create a new node at the end of the beam.

n Create a RBAR.

n Delete the moment at node 6.

n Add a point force to the newly created Node 7.

n Resubmit the model to MSC.Nastran for analysis.

n Post-process results.

n Review the results.

n Quit MSC.Patran.

13c-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 9 otherwise, proceed to Step 2.

2. Open the database created in lesson 13a named lesson13a.db.

3. Resave this database as lesson13c.db.

Close the current database and open the newly save copylesson13c.db.

4. Select a preset view by selecting the Isoview_1 icon on the toolbar.

5. Verify the beam dimensions and offsets by switching to a 3D viewof the beam.

File/Open...

Existing Database Name lesson13a

OK

File/ Save a Copy...

Save Copy of Database as: lesson13cSave

File/ Close

File/Open...

Existing Database Name: lesson13c

OK

Display/Loads/BC/Elem. Props...

Beam Display 3D: Full-Span + Offsets

Apply

Cancel

Iso 1 View

MSC.Nastran 105 Exercise Workbook 13c-7

WORKSHOP 13c Load Analysis of a Beam

Figure 13c.2 - 3D representation of the beam.

6. Create a node in the location of the applied load, and then connectthis node to the end of the beam with a rigid element.

7. Create the rigid element.

u Finite ElementsAction: Create

Object: NodeMethod: Edit

q Associate with Geometry

q Auto Execute

Node Location List: [50, 2, 0]Apply

u Finite Elements

Action: Create

Object: MPCType: RBAR

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13c-8 MSC.Nastran 105 Exercise Workbook

The dependent node can be selected off the screen or directly typedinto the data box.

Select DOFs by holding the Shift key down while clicking with theleft mouse button.

8. The moment will be accounted for by applying a load off of the cen-ter of the beam. Delete the additional moment from the applied mod-el load.

Define Terms...

Auto Execute

u Create Dependant

Node List Node 7

DOFs: UX UY UZRXRYRZ

Apply

u Create Independent

Node List: Node 6

DOFs: UX UY UZRXRYRZ

Apply

Cancel

Apply

u Loads/BCsAction: Modify

Object: Force

MSC.Nastran 105 Exercise Workbook 13c-9

WORKSHOP 13c Load Analysis of a Beam

Figure 13c.3 - Beam model with rigid element and applied load.

9. Create an input file for analysis.

Type: Nodal

Select Set to Modify loadModify Data...

Force < F1 F2 F3 > < -100, 0, 0 >

Moment < M1 M2 M3 > < >

OK

Modify Application Region...

Geometry Filter: u FEM

Select Nodes: Node 6

Remove

Select Nodes: Node 7Add

OK

Apply

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13c-10 MSC.Nastran 105 Exercise Workbook

A MSC.Nastran input file called lesson13c.bdf will be generated.This process of translating the model into an input file is called theForward Translation. The Forward Translation is complete when theHeartbeat turns green. MSC.Patran Users should proceed to step 10.

u AnalysisAction: Analyze

Object: Entire ModelMethod: Analysis Deck

Job Name: lesson13c

Apply

MSC.Nastran 105 Exercise Workbook 13c-11

WORKSHOP 13c Load Analysis of a Beam

Generating an input file for MSC.Nastran Users:10. MSC.Nastran users can generate an input file using the

data from pages 13a-5, 13a-6, and 13c-3. The result shouldbe similar to the output below (lesson13c.dat):

ID SEMINAR, lesson13cSOL 101TIME 600CENDTITLE = MSC.Nastran jobECHO = UNSORTEDMAXLINES = 999999999SUBCASE 1$ Subcase name : Default SUBTITLE=Default SPC = 2 LOAD = 2 DISPLACEMENT(SORT1,REAL)=ALL SPCFORCES(SORT1,REAL)=ALL STRESS(SORT1,REAL,VONMISES,BILIN)=ALLBEGIN BULKPARAM POST -1PARAM PATVER 3.PARAM AUTOSPC YESPARAM INREL 0PARAM ALTRED NOPARAM COUPMASS -1PARAM K6ROT 0.PARAM WTMASS 1.PARAM,NOCOMPS,-1PARAM PRTMAXIM YES$ Elements and Element Properties for region : beamPBAR 1 1 .97 2.64660 .200308 .005783 + A+ A 2. 1. -2. 1. -2. -1. 2. -1. + B+ B .381443 .618557 0.CBAR 1 1 1 2 0. 1. 0.CBAR 2 1 2 3 0. 1. 0.CBAR 3 1 3 4 0. 1. 0.CBAR 4 1 4 5 0. 1. 0.CBAR 5 1 5 6 0. 1. 0.$ Material Record : mat1MAT1 1 1.+7 .3$ Multipoint Constraints of the Entire ModelRBAR 6 7 6 123456 123456

13c-12 MSC.Nastran 105 Exercise Workbook

$ Nodes of the Entire ModelGRID 1 0. 0. 0.GRID 2 10. 0. 0.GRID 3 20. 0. 0.GRID 4 30. 0. 0.GRID 5 40. 0. 0.GRID 6 50. 0. 0.GRID 7 50. 2. 0.$ Loads for Load Case : DefaultSPCADD 2 1LOAD 2 1. 1. 1$ Displacement Constraints of Load Set : fixedSPC1 1 123456 1$ Nodal Forces of Load Set : loadFORCE 1 7 0 100. -1. 0. 0.$ Referenced Coordinate FramesENDDATA

MSC.Nastran 105 Exercise Workbook 13c-13

WORKSHOP 13c Load Analysis of a Beam

SUBMITTING THE INPUT FILE FOR MSC.Nastran and MSC.Patran USERS:

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

11a. To submit the MSC.Patran .bdf file, find an available UNIXshell window. At the command prompt enter nastranlesson13c.bdf scr=yes. Monitor the run using the UNIX pscommand.

11b. To submit the MSC.Nastran .dat file, find an available UNIXshell window and at the command prompt enter nastranlesson13c scr=yes. Monitor the run using the UNIX pscommand.

12. When the run is completed, edit the lesson13c.f06 file and search forthe word FATAL. If no matches exist, search for the word WARN-ING. Determine whether existing WARNING messages indicatemodeling errors.

12a. While still editing lesson13c.f06, search for the word:

D I S P L A C E (spaces are necessary).

13c-14

MSC.N

astran 105

Exercise W

orkbook

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 -1.030928E-04 3.778421E-04 0.0 0.0 0.0 7.556842E-05 3 G -2.061856E-04 1.511368E-03 0.0 0.0 0.0 1.511368E-04 4 G -3.092783E-04 3.400579E-03 0.0 0.0 0.0 2.267052E-04 5 G -4.123711E-04 6.045473E-03 0.0 0.0 0.0 3.022737E-04 6 G -5.154639E-04 9.446052E-03 0.0 0.0 0.0 3.778421E-04 7 G -1.271148E-03 9.446052E-03 0.0 0.0 0.0 3.778421E-04

MSC.Nastran 105 Exercise Workbook 13c-15

WORKSHOP 13c Load Analysis of a Beam

Comparison of Results:13. Compare the results obtained in the .f06 file with the results on the

previous page:

Also compare the displacement and rotation results on thefollowing page for Node 6 and Node 7 to the results found inLesson 13a and Lesson 13b.

Table 13c.1 - Translation and Rotation Results

LESSON 13a LESSON 13b LESSON 13c

Node 6 6 6 7

X-Translation -5.15E-04 -1.27E-04 -5.15E-04 -1.27E-04

Y-Translation 9.44E-03 9.44E-03 9.44E-03 9.44E-03

Z-Rotation 3.77E-04 3.77E-04 3.77E-04 3.77E-04

13c-16 MSC.Nastran 105 Exercise Workbook

14.MSC.Nastran Users have finished this exercise. MSC.Patran Users should proceed to the next step.

Reset the graphics using the Reset Graphics icon.

15. When the translation is complete and the Heartbeat turns green, bring up the Results form.

Plot the deformation in the X-direction.

u AnalysisAction: Attach XDB

Object: Result Entities

Method: Translate

Select Results File...

Selected Results File lesson13c.xdb

Ok

Apply

u ResultsAction: Create

Object: Deformation

Select Result Case(s) Default, Static SubcaseSelect Deformation Result Displacements, TranslationalShow As: Component

n XX q YY q ZZ

Apply

Reset Graphics

MSC.Nastran 105 Exercise Workbook 13c-17

WORKSHOP 13c Load Analysis of a Beam

Figure 13c.4 - Deformation plot of X component of deflections.:

Note: Compare the results to what was found in the .f06 file on Page 13c-13.

15a. Plot the deformation in the Y-direction.

u ResultsAction: Create

Object: Deformation

Select Result Case(s) Default, Static SubcaseSelect Deformation Result Displacements, TranslationalShow As: Component

o XX n YY q ZZ

Apply

13c-18 MSC.Nastran 105 Exercise Workbook

Figure 13c.5 - Deformation plot of Y component of deflections.:

Note: Compare the results to what was found in the .f06 file on Page 13c-13.

15b.Find the total deformation.

u ResultsAction: Create

Object: Deformation

Select Result Case(s) Default, Static SubcaseSelect Deformation Result Displacements, TranslationalShow As: Resultant

Apply

MSC.Nastran 105 Exercise Workbook 13c-19

WORKSHOP 13c Load Analysis of a Beam

Figure 13c.6 -Deformation of plot of resultant vector of deformations.

Note: Compare the results to what was found in the .f06 file on page 13c-13.

16. Reset the graphics using the Reset Graphics icon.

Quit MSC.Patran when you are finished with this exercise.

Reset Graphics

13c-20 MSC.Nastran 105 Exercise Workbook