NAS102 Dynamic Exercise

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MSC.Nastran Dynamic Analysis NAS102 Workbook

March 2004

Part Number:NA*V2004*Z*Z*Z*SM-NAS102-WBK

DISCLAIMER

MSC.Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice. The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software Corporation assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any information contained herein. User Documentation: Copyright© 2004 MSC.Software Corporation. Printed in U.S.A. All Rights Reserved. This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or distribution of this document, in whole or in part, without the prior written consent of MSC.Software Corporation is prohibited. MSC and MSC. are registered trademarks and service marks of MSC.Software Corporation. NASTRAN is a registered trademark of the National Aeronautics and Space Administration. MSC.Nastran is an enhanced proprietary version developed and maintained by MSC.Software Corporation. MSC.Patran is a trademark of MSC.Software Corporation. All other trademarks are the property of their respective owners.

TABLE OF CONTENTS No.

Title

1.

Modal Analysis of a Flat Plate 2. Modal Analysis of a Flat Plate using Static Reduction 3. Direct Transient Response Analysis 4. Modal Transient Response Analysis 5. Direct Frequency Response Analysis 6. Modal Frequency Response Analysis 6a. Modal Frequency Response Analysis 7a. Direct Transient Response with Base Excitation 8a. Enforced Motion with Direct Frequency Response 9a. Response Spectra 9b. Response Spectra (cont.) 10. Random Analysis 11. Random Analysis 12. Complex Modes of a Pile Driver 13. Nolins in Linear Transient 14a. Modal Analysis of a Beam 14b. Normal Modes with Differential Stiffness 15. Weight Minimization of a Three Bar Truss Appendix Title 1a. Modal Analysis of a Beam (SI Units) 1b. Normal Modes with Differential Stiffness (SI Units) 1c. Normal Modes with Differential Stiffness, using STATSUB 7. Direct Transient Response with Base Excitation 8. Enforced Motion with Direct Frequency Response

WORKSHOP 1 MODAL ANALYSIS OF A FLAT PLATE

NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

WS1-1


WS1-2

Workshop 1 – Modal Analysis of a Flat Plate

Objectives

Produce a MSC.Nastran input file. Submit the file for analysis in MSC.Nastran. Find the first five natural frequencies and mode shapes of the flat plate.


WS1-3


Problem Description

For this workshop, use Lanczos method to find the first five natural frequencies and mode shapes of a flat rectangular plate. One of the edges is fixed (See Figure 1.2). Below is a finite element representation of the rectangular plate. It also contains the geometric dimensions. Table 1.1 contains the necessary parameters to construct the input file.

b

a

Figure 1.1 - Grid Coordinates and Element Connectivities


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Figure 1.2 Loads and Boundary Conditions Length (a)

5 in

Height (b)

2 in

Thickness

0.100 in

Weight Density

0.282 lbs/in3

Mass/Weight Factor

2.59E-3 sec2/in

Elastic Modulus

30.0E6 psi

Poisson’s Ratio

0.3

Table 1.1 NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

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Natural Frequency: Hertz 2 3 1⁄2 λ ij Eh fij = ------------ ---------------------------2 2 2 πa 12 γ( 1 – ν )

Where i = 1,2,3, … j = 1,2,3, …


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Description: Clamped-Free-Free-Free

a = length of plate b = width of plate h = thickness of plate i = number of half-waves in mode shape along horizontal axis j = number of half-waves in mode shape along vertical axis C = clamped edge E = modulus of elasticity F = free edge S = simply supported edge γ = mass per unit area of plate (μh for a plate material with density μ ) υ = Poisson ratio


WS1-7

Workshop 1 – Modal Analysis of a Flat Plate λij2 and (ij)

Mode Sequence

a/b

1

2

3

4

5

6

0.40

3.511

4.786

8.115

13.88

21.64

23.73

(11)

(12)

(13)

(14)

(21)

(22)

3.502

6.406

14.54

22.04

26.07

31.62

(11)

(12)

(13)

(21)

(22)

(14)

3.492

8.525

21.43

27.33

31.11

54.44

(11)

(12)

(21)

(13)

(22)

(23)

3.477

11.68

21.62

39.49

53.88

61.99

(11)

(12)

(21)

(22)

(13)

(31)

3.456

17.99

21.56

57.46

60.58

106.5

(11)

(12)

(21)

(22)

(31)

(32)

2/3

1.0

1.5

2.5

υ = 0.3 NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

WS1-8


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Define the plate structure using grid points (GRID) and elements (CQUAD4). 2. Define material (MAT1) and element (PSHELL) properties. 3. Apply the fixed boundary constraints (SPC1). 4. Prepare the model for a normal modes analysis (SOL 103 and PARAMs). z z

PARAM, WTMASS, 0.00259 PARAM, COUPMASS, 1

5. Create a complete input file prob1.dat. Also create a model file plate.dat which contains only model data. 6. Go to step 9 under MSC.Patran users.


WS1-9

Workshop 1 – Modal Analysis of a Flat Plate ID SEMINAR, PROB1 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 1 – Modal Analysis of a Flat Plate 1

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Workshop 1 – Modal Analysis of a Flat Plate 1

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ENDDATA


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MSC.Nastran MSC.NastranUsers Usersshould shouldgo goto toStep Step99

MSC.Patran Users 1. Create a new database. 2. Create a surface. 3. Create a finite element mesh. 4. Create material properties. 5. Create 2D shell properties. 6. Create boundary conditions. 7. Create an MSC.Nastran model file. 8. Create an MSC.Nastran input file. 9. Review the MSC.Nastran model file and input file. 10. Submit the model to MSC.Nastran for analysis. 11. Review the .F06 file. 12. Attach the XDB file. 13. View Results.


WS1-13

Step 1. Create a Database

a

d Create a new database named prob1.db. a. File / New. b. Enter prob1 as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


e f b

c

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g

Step 2. Create a Surface d

Create a surface. a. Geometry: Create / Surface / XYZ. b. Enter <5 2 0> for the Vector Coordinate List. c. Click Apply. d. Activate the entity labels by selecting the Show Labels icon on the toolbar.

a

b

c


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Step 3. Create Finite Element Mesh

c Create the finite element model. a. Elements: Create / Mesh Seed / Uniform. b. Enter 10 as the Number. c. Screen pick the upper edge. d. Enter 4 as the Number. e. Screen pick the right edge.


a

e

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b

d

Step 3. Create Finite Element Mesh

a Mesh the surface. a. Elements: Create / Mesh / Surface. b. Screen pick the surface c. Click Apply.

b

c NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

WS1-17

Step 4. Create Material Properties

a Create a set of material properties for the plate. a. Materials: Create / Isotropic / Manual Input. b. Enter mat_1 as the material name. c. Click Input Properties. d. Enter 30e6 as the Elastic Modulus. e. Enter 0.30 as the Poisson Ratio. f. Enter .282 as the Density. g. Click OK. h. Click Apply.

d e f

b

g c h NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 5. Create 2D Shell Properties a

a Define the plate thickness. a. Properties: Create / 2D / Shell. b. Enter plate as the property set name. c. Click Input Properties. d. Click the material prop icon. e. select mat_1 from Material Property Sets box. f. Enter 0.100 as the Thickness. g. Click OK.

d f e

b

c

g


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Step 5. Create 2D Shell Properties (cont.)

a. Click in Select Members box. b. Screen pick the surface. c. Click Add. d. Click Apply.

b

a c


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d

Step 6. Create Boundary Conditions

a

a Fix the left side by creating a displacement boundary. a. Loads/BCs: Create / Displacement / Nodal. b. Enter fixed as the New Set Name. c. Click Input Data. d. Enter <0,0,0> for Translations. e. Enter <0,0,> for Rotations. f. Click OK.

d e

b

c

f NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

WS1-21

Step 6. Create Boundary Conditions (cont.)

a. Click Select Application Region. b. Click in Select Geometry Entities box. c. Select Curve or Edge icon. d. Screen pick the left edge. e. Click Add. f. Click OK. g. Click Apply.

b e

d

f c a g NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 7. Create a Model File

a

a Before the complete input file is generated for this analysis, a file that contains only the model data needs to be created. This file is to be used in later workshops. a. Analysis: Analyze / Entire Model / Model Only. b. Enter plate as the Job Name. c. Click Apply.

b


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Step 8. Create the Input File

a

d

Generate the input file for analysis. a. Analysis: Analyze / Entire Model / Analysis Deck. b. Enter prob1 as the Job Name. c. Click Translation Parameters. d. Check XDB and Print. e. Click OK.

b

c

e NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

WS1-24

Step 8. Create the Input File (cont.)

a. Click Solution Type. b. Select NORMAL MODES for Solution Type. c. Click Solution Parameters. d. Select Coupled for Mass Calculation. e. Select Unsorted for Data Deck Echo. f. Enter .00259 for Wt.Mass Conversion. g. Click OK. h. Click OK.

b d e

f

c a h g NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

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a. Click Subcases. b. Select Default under Available Subcases. c. Click Subcase Parameters. d. Enter 5 for Number of Desired Roots. e. Click OK. f. Click Output Requests.

b

d

c f e


a

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a. Select SPCFORCES(SORT1,RE AL)=All FEM. b. Click Delete. c. Click OK. d. Click Apply. e. Click Cancel. f. Click Apply.

a

b

d


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e

f


An MSC.Nastran input file called prob1.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to step 10.


WS1-28

Step 9A: Review Input File for MSC.Nastran Users

For MSC.Nastran users who created the input file using a text editor, the input file (prob1.dat) should be similar to the file below:

ID SEMINAR, PROB1 SOL 103 TIME 600 CEND TITLE = NORMAL MODES EXAMPLE ECHO = UNSORTED SUBCASE 1 SUBTITLE= USING LANCZOS METHOD = 1 SPC = 1 VECTOR=ALL BEGIN BULK PARAM COUPMASS 1 PARAM WTMASS .00259 EIGRL 1 PSHELL 1 1 .1 CQUAD4 1 1 1 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 11 1 12 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 21 1 23 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 31 1 34 =,*1,=,*1,*1,*1,*1 =8

5 1 2

13

1 12

13

24

23

24

35

34

35

46

45


MAT1 1 GRID 1 =,*1,=,*0.5,== =9 GRID 12 =,*1,=,*0.5,== =9 GRID 23 =,*1,=,*0.5,== =9 GRID 34 =,*1,=,*0.5,== =9 GRID 45 =,*1,=,*0.5,== =9 SPC1 1 45 ENDDATA

WS1-29

3.+7

12345

0.

.3 0.

.282 0.

0.

.5

0.

0.

1.

0.

0.

1.5

0.

0.

2.

0.

1

12

23

34

Step 9B: Review Model File for MSC.Nastran Users

For MSC.Nastran users who created the model file using a text editor, the model file (plate.dat) should be similar to the file below: GRID 1 =,*1,=,*0.5,== =9 GRID 12 =,*1,=,*0.5,== =9 GRID 23 =,*1,=,*0.5,== =9 GRID 34 =,*1,=,*0.5,== =9 GRID 45 =,*1,=,*0.5,== =9 PSHELL 1 1 CQUAD4 1 1 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 11 1 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 21 1 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 31 1 =,*1,=,*1,*1,*1,*1 =8 MAT1 1 3.+7 SPC1 1 12345 45


0.

0.

0.

0.

.5

0.

0.

1.

0.

0.

1.5

0.

0.

2.

0.

.1 1

1 2

13

1 12

12

13

24

23

23

24

35

34

34

35

46

45

1

.3 12

.282 23

34

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Step 10: Submitting the Input File for Analysis

Windows Users:

Submit the input file to MSC.Nastran for analysis

Double click on MSC.Nastran icon. Select prob1.bdf or prob1.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


WS1-31


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob1.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob1 scr=yes. Monitor the run using the UNIX ps command.


WS1-32

Step 11: Review F06 File

When the run is completed, edit the prob1.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.

While still editing prob1.f06, search for the word R E A L (spaces are necessary). 1st = __________Hz 2nd = __________Hz 3rd = __________Hz 4th = __________Hz 5th = __________Hz


WS1-33

Step 11: Review F06 File (cont.)

Compare the results obtained in the .f06 file with the following results:

MSC.Nastran MSC.NastranUsers Usershave havefinished finishedthis thisworkshop. workshop. MSC.Patran MSC.PatranUsers Users should shouldproceed proceedto tothe thenext nextstep. step.


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Step 12. Attach the XDB g

f a

Proceed with the Reverse Translation process, that is attaching the prob.xdb results file to MSC.Patran. To do this, return to the Analysis form and proceed as follows. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click Select Results File. c. Select prob1.xdb. d. Click OK. e. Click Apply. f. Turn off entity labels. g. Select Iso 3 view.

a

c

d

b


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Step 13. View Results

a

View the mode shapes. a. Results: Create / Deformation. b. Select Default, A1:Mode 1 : Freq. = 133.69 for Select Results Cases. c. Select Eigenvectors, Translational for Select Deformation Result. d. Click Apply. e. Repeat the procedure to view the other mode shapes. f. Quit MSC.Patran when you are finished with this workshop.

b

c

d NAS102, Workshop 1, January 2004 Copyright© 2004 MSC.Software Corporation

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WORKSHOP 2 MODAL ANALYSIS OF A FLAT PLATE USING STATIC REDUCTION


WS2-1


WS2-2

Workshop 2 – Modal Analysis of a Flat Plate Using Static Reduction

Objectives

Reduce the dynamic math model, created in Workshop 1, to one with fewer degrees of freedom. Produce an MSC.Nastran input file. Submit the file for analysis in MSC.Nastran. Find the first five natural frequencies and mode shapes of the flat plate.


WS2-3


Problem Description

For this example, reduce the dynamic math model created in Workshop 1, using static reduction. Then find the first five natural frequencies and mode shapes using the Automatic Givens method. Use the points indicated in Figure 2.2 for the A-set.

b

a

Figure 2.1 – Grid Coordinates and Element Connectivities


WS2-4


Figure 2.2 – Loads and Boundary Conditions Length (a)

5 in

Height (b)

2 in

Thickness

0.100 in

Weight Density

0.282 lbs/in3

Mass/Weight Factor

2.59E-3 sec2/in

Elastic Modulus

30.0E6 lbs/in2

Poisson’s Ratio

0.3

Table 2.1


WS2-5


MSC.Nastran Users – Generate a MSC.Nastran input 1. Reference a previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Prepare the model for a normal modes analysis (SOL 103 and PARAMs). PARAM, WTMASS, 0.00259 PARAM, COUPMASS, 1 3. Define degrees of freedom in the analysis set (ASET) for grids indicated in Figure 2.2. 4. Generate an input file. 5. Go to step 5 under MSC.Patran users.


WS2-6

Workshop 2 – Modal Analysis of a Flat Plate Using Static Reduction ID SEMINAR, PROB2 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ 3 0 _____________________________________________ 5 _____________________________________________ 5 _____________________________________________ 7 _____________________________________________ 9 _____________________________________________ 0 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 2 – Modal Analysis of a Flat Plate Using Static Reduction 1

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Workshop 2 – Modal Analysis of a Flat Plate Using Static Reduction 1

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Workshop 2: Modal Analysis of a Flat Plate Using Static Reduction


MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8.

Create a new database. Import the input file. Add pre-defined constraints. Create the new analysis deck. Submit the input file for analysis. Review the F06 file. Attach the XDB. View the Results.


WS2-10

Step 1: Create New Database a

d Create a new database called prob2.db. a. File / New. b. Enter prob2 as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


e f b

c

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g

Step 2: Import the Input File h e

a In the Analysis menu, a. Read Input File/Model Data. b. Enter prob2 for job name. c. Click on Select Input File. d. Select plate.bdf. e. Click OK. f. Click Apply. g. Click OK. h. Click on the Show Labels icon.

d

e

b

c f g NAS102, Workshop 2, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 3: Add the Pre-Defined Constraints

a In the Load Cases menu, a. Select Modify for Action. b. Under Existing Load Cases, select Default. c. Select Displ_spc1.1 under Select Individual Loads/BCs. d. Click OK. e. Click Apply.

c

b


d WS2-13

Step 4: Create the New Analysis Deck

In the Analysis menu, a. Analyze/Entire Model/Analysis Deck. b. Enter prob2 for Job Name. c. Click on Translation Parameters. d. Select XDB and Print. e. Click OK. f. Click on Solution Type…

a

d

b

c f


WS2-14

Step 4: Create the New Analysis Deck (cont.)

a. Select NORMAL MODES. b. Click on Solution Parameters… c. Mass Calculation: Coupled, Data Deck Echo: Unsorted, Wt.Mass Conversion = 0.00259. d. Click OK. e. Click OK.

a c

b

d


WS2-15


a. Click on Direct Text Input… b. In the Bulk Data Section, type in the following:

b ASET1,345,3,5,7,9,11 ASET1,345,25,27,29,31,33 ASET1,345,47,49,51,53,55 c. Click OK.

c

a


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b a. Click Subcases… b. Select Create. c. Select Default under Available Subcases. d. Click on Subcase Parameters… e. Select Automatic Givens for Extraction Method. f. Enter 5 as the Number of Desired Roots. g. Click OK.

c

e

f

d

a g


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a. Click on Output Requests… b. Under Output Requests, highlight SPCFORCES(SORT1, REAL)=ALL FEM c. Click on Delete. d. Click OK. e. Click Apply. f. Click Cancel. g. Click Apply.

b

a c


f WS2-18

d

g


An MSC.Nastran input file called prob2.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to Step 6.


WS2-19

Step 5: Review Input File for MSC.Nastran Users

For MSC.Nastran users who created the input file using a text editor, the input file (prob2.dat) should be similar to the file below: ID SEMINAR, PROB2 SOL 103 TIME 10 CEND TITLE = REDUCTION PROCEDURES, NORMAL MODES EXAMPLE SUBTITLE = USING STATIC REDUCTION ECHO = UNSORTED SUBCASE 1 SUBTITLE=USING LANCZOS METHOD = 1 SPC = 1 VECTOR=ALL BEGIN BULK EIGR,1,AGIV,,,,5 PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 INCLUDE ’plate.bdf’ $ $ SELECT A-SET, STATIC REDUCTION IS DONE AUTOMATICALLY $ ASET1,345,3,5,7,9,11 ASET1,345,25,27,29,31,33 ASET1,345,47,49,51,53,55 ENDDATA


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Windows Users:




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Unix Users:




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While still editing prob2.f06, search for the word R E A L (spaces are necessary) 1st = __________Hz 2nd = __________Hz 3rd = __________Hz 4th = __________Hz 5th = __________Hz


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Step 8: Attach XDB f

g

a Proceed with the Reverse Translation process, that is attaching the prob.xdb results file into MSC.Patran. To do this, return to the Analysis form and proceed as follows. a. Analysis: Attach Results / Attach XDB / Result Entities. b. Click Select Results File. c. Select prob2.xdb. d. Click OK. e. Click Apply. f. Turn off entity labels g. Select Iso 3 view.

c

d

b


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Step 9: View the Results

a When the translation is complete bring up the Results form. a. Results: Create / Deformation. b. Select Default, A1:Mode 1 : Freq. = 133.69 for Select Results Cases. c. Select Eigenvectors, Translational for Select Deformation Result. d. Click Apply. e. Repeat the procedure to view the other mode shapes. f. Quit MSC.Patran when you are finished with this exercise.

b

c


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WORKSHOP 3 DIRECT TRANSIENT RESPONSE ANALYSIS


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Workshop 3 – Direct Transient Response Analysis

Objectives

Define time-varying excitation. Produce a MSC.Nastran input file from dynamic math model created in Workshop 1. Submit file for analysis in MSC.Nastran. Compute nodal displacements for desired time domain.


WS3-3


Problem Description

Using the direct method, determine the transient response of the flat rectangular plate, created in Workshop 1, under timevarying excitation. This example structure shall be excited by 1 psi pressure load over the total surface of the plate varying at 250Hz. In addition, a 50 lb force is applied at a corner of the tip also varying at 250Hz but out-of-phase with the pressure load. Both time dependent dynamic loads are applied for the duration of 0.008 seconds only. Use structural damping of g=0.06 and convert this damping to equivalent viscous damping at 250Hz. Carry the analysis for 0.04 seconds.


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1 psi over the total surface

50.00

Figure 3.1 Loads and Boundary Conditions


WS3-5


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Define the time-varying pressure loading (PLOAD2, LSEQ and TLOAD2). (Hint, be certain to specify phase angle since the applied loads are out-ofphase). 3. Define the time-varying tip load (DAREA and TLOAD2). (Again, be certain to specify the phase angle). 4. Combine the time-varying loads (DLOAD). 5. Prepare the model for a direct transient analysis (SOL 109). 6. Specify the structural damping and convert this damping to equivalent viscous damping. z PARAM, G, 0.06 z PARAM, W3, 1571.0 7. Request response in terms of nodal displacement at grid points 11, 33, and 55. 8. Generate an input file and submit it to the MSC.Nastran solver for direct transient analysis. 9. Review the results, specifically the nodal displacements and xy-plot output.


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Workshop 3 – Direct Transient Response Analysis ID SEMINAR, PROB3 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 3 – Direct Transient Response Analysis 1

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Workshop 3 – Direct Transient Response Analysis 1

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MSC.Nastran MSC.NastranUsers Usersshould shouldgo goto tostep step77

MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Create a new database. Import an existing model. Create a load case. Create time dependent fields. Create load/boundary conditions. Create a MSC.Nastran input file. Review the MSC.Nastran input file. Submit the input file to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. View results.


WS3-10

Step 1. Create New Database

a



e f c

b

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g

Step 2. Import Existing Model

e

a b

c

c

Import the model from a Nastran Input File. a. File / Import. b. Select MSC.Nastran Input as the Source. c. Select plate.bdf and click Apply. d. Click OK when the Nastran Input File Import Summary appears. e. Click Show Labels.

d d NAS102, Workshop 3, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 3. Create Load Case

Create a Time Dependent load case called transient_response. a. Load Cases: Create. b. Enter transient_response for the Load Case Name. c. Change the Load Case Type to Time Dependent. d. Click Assign/Prioritize Loads/BCs. e. Select Displ_spc1.1. f. Click OK. g. Click Apply.

a e

b c

d

f g NAS102, Workshop 3, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 4. Create Time Dependent Fields

a

Create a time-dependent non-spatial field. a. Fields: Create / Non Spatial / Tabular Input b. Enter time_dependent_pressure for the Field Name. c. Click [Options…]. d. Enter 21 for Maximum Value of t. e. Click OK.

b d

e


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c

Step 4. Create Time Dependent Fields (cont.)

f. Click Input Data. g. Click Map Function to Table. h. Insert the parameters shown in the figure. i. Click Apply. j. Click Cancel.

h

i

g

j

f


WS3-15


k. For row 21 in the table, enter 0.04 for Time(t) and 0.0 for Value. l. Click OK. m. Click Apply.

k

l

m NAS102, Workshop 3, January 2004 Copyright© 2004 MSC.Software Corporation

WS3-16


a

Create another time-dependent field for the transient response of the nodal force. a. Fields: Create / Non Spatial / Tabular Input b. Enter time_dependent_force for the Field Name. c. Click [Options…]. d. Enter 21 for Maximum Value of t. e. Click OK.

b d

e


WS3-17

c



h

i


g

j

f

WS3-18



k

l


WS3-19

Step 5. Create Load/Boundary Conditions

Create the time-dependent pressure load. a. Loads/BCs: Create / Pressure / Element Uniform. b. Enter pressure for the New Set Name. c. Change the Target Element Type to 2D. d. Click on the Input Data button. e. Enter -1 for Top Surf Pressure, and select time_dependent_pre ssure for the Time/Freq. Dependent Field. f. Click OK. g. Click on Select Application Region. h. Choose FEM i. Select all the elements for the application region. j. Click Add, and click OK. k. Click Apply.

a

e

h

i j


b

f c

d g

j k WS3-20

Step 5. Create Load/Boundary Conditions (cont.)

Create the time-dependent force load. a. Loads/BCs: Create / Force / Nodal. b. Enter force for the New Set Name. c. Click on the Input Data button. d. Enter <0,0,50> for Force, and select time_dependent_for ce for the Time/Freq. Dependent Field. e. Click OK. f. Click on Select Application Region. g. Change the Geometry Filter to FEM. h. Select Node 11 on the bottom right corner of the plate. i. Click Add, and click OK. j. Click Apply.

a

d

g d h i


b

e

c i

f j WS3-21

Step 5. Create Load/Boundary Conditions (cont.) a

b

c

a. Hide labels. b. Switch to Iso 3 View. c. Loads/BCs: Plot Markers. d. Under Assigned Load/BC Sets, select Displ_spc1.1, Force_force, and Press_pressure. e. Under Select Groups, select default_group. f. Click Apply.

d

e


WS3-22

Step 6. Create Input File

a


d

b

c


WS3-23

Step 6. Create Input File (cont.)

Generate the input file for analysis (cont.). a. Click on Solution Type. b. Select Transient Response. c. Change the Formulation to Direct. d. Click on Solution Parameters. e. Enter 0.00259 for WtMass Conversion.

b e

f. Enter 0.06 for Struct. Damping Coefficient and 1571 for W3, Damping Factor. g. Click OK. h. Click OK.

c d

f

a h

g NAS102, Workshop 3, January 2004 Copyright© 2004 MSC.Software Corporation

WS3-24


Generate the input file for analysis (cont.). a. Click on Subcases. b. Select transient_response from the Available Subcases field. c. Click on Subcase Parameters. d. Click on DEFINE TIME STEPS button.

d b

g

e. Change Delta-T to 0.0004. Click Enter. f. Click OK. g. Click OK.

e

c a


WS3-25


Generate the input file for analysis (cont.). a. Click on Output Requests. b. Change Form Type to Advanced. c. Under Output Requests, select SPCFORCES(SORT2, REAL)=All FEM and click Delete. d. Select DISPLACEMENT(SOR T2,REAL)=All FEM and select By Freq/Time under Options: Sorting. e. Click OK. f. Click Apply. g. Click Cancel.

b d

d c

c

a

e f NAS102, Workshop 3, January 2004 Copyright© 2004 MSC.Software Corporation

WS3-26

g


Generate the input file for analysis (cont.). a. Click on Subcase Select. b. Select transient_response and unselect Default. c. Click OK. d. Click Apply.

b

b

c a d NAS102, Workshop 3, January 2004 Copyright© 2004 MSC.Software Corporation

WS3-27




WS3-28



D SEMINAR, PROB3 SOL 109 TIME 30 CEND TITLE= TRANSIENT RESPONSE WITH TIME DEPENDENT PRESSURE AND POINT LOADS SUBTITLE= USE THE DIRECT METHOD ECHO= PUNCH SPC= 1 SET 1= 11, 33, 55 DISPLACEMENT= 1 SUBCASE 1 DLOAD= 700 $ SELECT TEMPORAL COMPONENT OF TRANSIENT LOADING LOADSET= 100 $ SELECT SPACIAL DISTRIBUTION OF TRANSIENT LOADING TSTEP= 100 $ SELECT INTEGRATION TIME STEPS $ OUTPUT (XYPLOT) XGRID=YES YGRID=YES XTITLE= TIME (SEC) YTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER XYPLOT DISP RESPONSE / 11 (T3) YTITLE= DISPLACEMENT RESPONSE AT CENTER TIP XYPLOT DISP RESPONSE / 33 (T3) YTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER XYPLOT DISP RESPONSE / 55 (T3) $ BEGIN BULK PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $


INCLUDE ’plate.bdf’ $ $ SPECIFY STRUCTURAL DAMPING $ 3 PERCENT AT 250 HZ. = 1571 RAD/SEC. $ PARAM, G, 0.06 PARAM, W3, 1571. $ $ APPLY UNIT PRESSURE LOAD TO PLATE $ LSEQ, 100, 300, 400 $ PLOAD2, 400, 1., 1, THRU, 40 $ $ VARY PRESSURE LOAD (250 HZ) $ TLOAD2, 200, 300, , 0, 0., 8.E-3, 250., -90. $ $ APPLY POINT LOAD OUT OF PHASE WITH PRESSURE LOAD $ TLOAD2, 500, 600, , 0, 0., 8.E-3, 250., 90. $ DAREA, 600, 11, 3, 1. $ $ COMBINE LOADS $ DLOAD, 700, 1., 1., 200, 50., 500 $ $ SPECIFY INTERGRATION TIME STEPS $ TSTEP, 100, 100, 4.0E-4, 1 $ ENDDATA

WS3-29

Step 8: Submit Input File for Analysis

Windows Users:




WS3-30

Step 8: Submit Input File for Analysis (cont.)

Unix Users:




WS3-31


MSC.Nastran users use plotps utility to create a postscript file, prob3.ps, from the binary plot file, Prob3.plt.


While still editing prob3.f06, search for the word D I S P L (spaces are necessary) Displacement at Grid 11 Time

T3

.0024 = ___________ .0052 = ___________ .02

= ___________


WS3-32

Step 9: Review F06 File (cont.) Displacement at Grid 33 Time

T3

.0024 = ___________ .0052 = ___________ .02

= ___________

Displacement at Grid 55 Time

T3

.0024 = ___________ .0052 = ___________ .02

= ___________


WS3-33




WS3-34




WS3-35

Step 10. Attach XBD File

Attach the XDB result file. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click on Select Results File. c. Select prob3.xdb. d. Click OK. e. Click Apply.

a

c

d

b

e


WS3-36


Create a X-Y graph of displacement results. a. Results: Create / Graph / Y vs X. b. Under Select Result case(s), click on transient_response, 0 of 101 subcases. c. Select All as the Filter Method. d. Click Filter. e. Click Apply. f. Click Close.

a

b c

d

f

e


WS3-37

Step 11. View Results (cont.)

Create a X-Y graph of displacement results (cont.). a. Select Displacement, Translational for the Select Y Result field. b. Select Z Component as the Quantity. c. Click on the Target Entities icon. d. Change the Target Entity Selection to Nodes. e. Select the bottom right node where the force was applied. f. Click Apply.

c

d e

a

To plot displacements of other nodes, simply select them and click Apply.

b f


WS3-38


Displacement Response at Node 11

Node 55 Displacement


WS3-39




WS3-40




WS3-41


WS3-42

WORKSHOP 4 MODAL TRANSIENT RESPONSE ANALYSIS


WS4-1


WS4-2

Workshop 4 – Modal Transient Response Analysis

Objectives



WS4-3


Problem Description

Using the modal method, determine the transient response of the flat rectangular plate, created in Workshop 1, under timevarying excitation. This example structure shall be excited by 1 psi pressure load over the total surface of the plate varying at 250Hz. In addition, a 25 lb force is applied at a corner of the tip also varying at 250Hz but starting .0004 seconds after the pressure load begins. Both time dependent dynamic loads are applied for the duration of 0.008 seconds only. Use structural damping of g=0.03 and convert this damping to equivalent viscous damping at 250Hz. Carry the analysis for 0.04 seconds.


WS4-4


1 psi over the total surface

25.00



WS4-5


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Specify modal damping as a tabular function of natural frequency (TABDMP1). 3. Define the time-varying tip load (DAREA and TLOAD2). 4. Combine the time-varying loads (DLOAD). 5. Specify integration time steps (TSTEP). 6. Prepare model for a modal transient analysis (SOL 112). 7. Request response in terms of nodal displacement at grid 11, 33, and 55. 8. Generate an input file and submit it to the MSC.Nastran solver for normal modes analysis. 9. Review the results, specifically the nodal displacements.


WS4-6

Workshop 4 – Modal Transient Response Analysis ID SEMINAR, PROB4 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS4-7

Workshop 4 – Modal Transient Response Analysis 1

2

3


4

5

6

WS4-8

7

8

9

10

Workshop 4 – Modal Transient Response Analysis 1

2

3

4

5

6

ENDDATA


WS4-9

7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.



WS4-10


a



e f c

b

WS4-11

g


e

a b

c

c



WS4-12



a e

b c

d

f g NAS102, Workshop 4, January 2004 Copyright© 2004 MSC.Software Corporation

WS4-13


a

Create a time-dependent non-spatial field. a. Fields: Create / Non Spatial / Tabular Input b. Enter time_dependent_pressure for the Field Name. c. Click [Options…]. d. Enter 21 for Maximum Value of t. e. Click OK.

b d

e


WS4-14

c



h

i

g

j

f


WS4-15



k

l


WS4-16


a

Create another time-dependent field for the transient response of the nodal force. a. Fields: Create / Non Spatial / Tabular Input b. Enter time_dependent_force for the Field Name. c. Click [Options…]. d. Enter 32 for Maximum Value of t. e. Click OK.

b d

e


WS4-17

c



h

i


g

j

f

WS4-18



k

l


WS4-19


Create the time-dependent pressure load. a. Loads/BCs: Create / Pressure / Element Uniform. b. Enter pressure for the New Set Name. c. Change the Target Element Type to 2D. d. Click on the Input Data button. e. Enter -1 for Top Surf Pressure, and select time_dependent_pre ssure for the Time/Freq. Dependent Field. f. Click OK. g. Click on Select Application Region. h. Choose FEM i. Select all the elements for the application region. j. Click Add, and click OK. k. Click Apply.

a

e

h

i j


b

f c

d g

j k WS4-20


Create the time-dependent force load. a. Loads/BCs: Create / Force / Nodal. b. Enter force for the New Set Name. c. Click on the Input Data button. d. Enter <0,0,25> for Force, and select time_dependent_for ce for the Time/Freq. Dependent Field. e. Click OK. f. Click on Select Application Region. g. Change the Geometry Filter to FEM. h. Select Node 11 on the bottom right corner of the plate. i. Click Add, and click OK. j. Click Apply.

a

d g

d h i


b e

c i

f j WS4-21


b

c

a. Hide labels. b. Switch to Iso 3 View. c. Loads/BCs: Plot Markers. d. Under Assigned Load/BC Sets, select Displ_spc1.1, Force_force, and Press_pressure. e. Under Select Groups, select default_group. f. Click Apply.

d

e


WS4-22


a


d

b

c


WS4-23


Generate the input file for analysis (cont.). a. Click on Solution Type. b. Select Transient Response. c. Change the Formulation to Modal. d. Click on Solution Parameters. e. Change the Mass Calculation to Coupled. f. Enter 0.00259 for WtMass Conversion.

e b f c d

i


WS4-24

a


Generate the input file for analysis (cont.). a. Click on Eigenvalue Extraction. b. Set the Number of Desired Roots to 5. c. Click OK. d. Click OK. e. Click OK.

b

a e

c


WS4-25



d b

e. Change Delta-T to 0.0004. Click Enter. f. Click OK.

e

c

a f NAS102, Workshop 4, January 2004 Copyright© 2004 MSC.Software Corporation

WS4-26


Generate the input file for analysis (cont.). a. Set Modal Damping to Crit. Damp. (CRIT). b. Click on DEFINE MODAL DAMPING button. c. Click Add Row. d. Enter 0 and 10 for the Frequency, and 0.03 for both values. e. Click OK. f. Click OK.

d

a b

c

f

e


WS4-27



b d

d c

c

a


WS4-28

g



b

b


WS4-29




WS4-30



ID SEMINAR, PROB4 SOL 112 TIME 30 CEND TITLE = TRANSIENT RESPONSE WITH TIME DEPENDENT PRESSURE AND POINT LOADS SUBTITLE = USE THE MODAL METHOD ECHO = UNSORTED SPC = 1 SET 111 = 11, 33, 55 DISPLACEMENT(SORT2) = 111 SDAMPING = 100 SUBCASE 1 METHOD = 100 DLOAD = 700 LOADSET = 100 TSTEP = 100 $ OUTPUT (XYPLOT) XGRID=YES YGRID=YES XTITLE= TIME (SEC) YTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER XYPLOT DISP RESPONSE / 11 (T3) YTITLE= DISPLACEMENT RESPONSE AT TIP CENTER XYPLOT DISP RESPONSE / 33 (T3) YTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER XYPLOT DISP RESPONSE / 55 (T3) $ BEGIN BULK PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE PROBLEM $ INCLUDE ’plate.bdf’


$ $ EIGENVALUE EXTRACTION PARAMETERS $ EIGRL, 100, , ,5 $ $ SPECIFY MODAL DAMPING $ TABDMP1, 100, CRIT, +, 0., .03, 10., .03, ENDT $ $ APPLY UNIT PRESSURE LOAD TO PLATE $ LSEQ, 100, 300, 400 $ PLOAD2, 400, 1., 1, THRU, 40 $ $ VARY PRESSURE LOAD (250 HZ) $ TLOAD2, 200, 300, , 0, 0., 8.E-3, 250., -90. $ $ APPLY POINT LOAD (250 HZ) $ TLOAD2, 500, 600,610, 0, 0.0, 8.E-3, 250., -90. $ DAREA, 600, 11, 3, 1. DELAY, 610, 11, 3, 0.004 $ $ COMBINE LOADS $ DLOAD, 700, 1., 1., 200, 25., 500 $ $ SPECIFY INTERGRATION TIME STEPS $ TSTEP, 100, 100, 4.0E-4, 1 $ ENDDATA

WS4-31


Windows Users:




WS4-32


Unix Users:




WS4-33


MSC.Nastran users use plotps utility to create a postscript file, prob4.ps, from the binary plot file, Prob4.plt.



T3

.0064 = ___________ .0092 = ___________ .02

= ___________


WS4-34


T3

.0068 = ___________ .0092 = ___________ .02

= ___________

Displacement at Grid 55 Time

T3

.0068 = ___________ .0092 = ___________ .02

= ___________


WS4-35




WS4-36




WS4-37



a

c

d

b e


WS4-38



a

b c

d

f

e


WS4-39


Create a X-Y graph of displacement results (cont.). a. Select Displacement, Translational for the Select Y Result field. b. Select Z Component as the Quantity. c. Click on the Target Entities icon. d. Change the Target Entity Selection to Nodes. e. Select the bottom right node where the force was applied. f. Click Apply.

c

d e

a

To plot displacements of other nodes, simply select them and click Apply.

b f


WS4-40


Displacement Response at Loaded Corner (Node 11)


WS4-41


Displacement Response at Tip Center (Node 33)


WS4-42


Displacement Response at Opposite Corner (Node 55)


WS4-43


WS4-44

WORKSHOP 5 DIRECT FREQUENCY RESPONSE ANALYSIS


WS5-1


WS5-2

Workshop 5 – Direct Frequency Response Analysis

Objectives

Define frequency-varying excitation. Produce a MSC.Nastran input file from dynamic math model created in Workshop 1. Submit file for analysis in MSC.Nastran. Compute nodal displacements for desired frequency domain.


WS5-3


Problem Description

Using the direct method, determine the frequency response of the flat rectangular plate, created in Workshop 1, under timevarying excitation. This example structure shall be excited by a unit load at a corner of the free side of the plate. Use a frequency step of 20 Hz between a range of 20 and 1000Hz. Use structural damping of g=0.06.

1.0



WS5-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Define the frequency-varying tip load (DAREA and RLOAD2). 3. Define a set of frequencies to be used in the solution. 4. Prepare the model for a direct frequency response analysis (SOL 108). 5. Specify the structural damping z PARAM, G, 0.06 6. Request response in terms of nodal displacement at grid points 11, 33, and 55. 7. Generate an input file and submit it to the MSC.Nastran solver for frequency response analysis. 8. Review the results, specifically the nodal displacements and phase angles.


WS5-5

Workshop 5 – Direct Frequency Response Analysis ID SEMINAR, PROB5 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS5-6

Workshop 5 – Direct Frequency Response Analysis 1

2

3


4

5

6

WS5-7

7

8

9

10

Workshop 5 – Direct Frequency Response Analysis 1

2

3

4

5

6

ENDDATA


WS5-8

7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.



WS5-9


a



e f g b

c

WS5-10


e

a b

c

c



WS5-11


Create a frequency-dependent load case called frequency_response. a. Load Cases: Create. b. Enter frequency_response for the Load Case Name. c. Change the Load Case Type to Time Dependent. d. Click Assign/Prioritize Loads/BCs. e. Select Displ_spc1.1. f. Click OK. g. Click Apply.

a e

b c

d f g NAS102, Workshop 5, January 2004 Copyright© 2004 MSC.Software Corporation

WS5-12

Step 4. Create Frequency Dependent Fields

Create a frequency-dependent non-spatial field. a. Fields: Create / Non Spatial / Tabular Input b. Enter frequency_dependent_load for the Field Name. c. Select Frequency (f) under Active Independent Variables. d. Click [Options…]. e. Enter 2 for Maximum Value of f. f. Click OK.

a

b e c

f


WS5-13

d

Step 4. Create Frequency Dependent Fields (cont.)

Create a frequency-dependent non-spatial field (cont.). a. Click Input Data… b. Enter 0 and 1000 for Freq(f), and 1.0 for both values in the table. c. Click OK. d. Click Apply.

b

a c


WS5-14


Create the frequencydependent unit force. a. Loads/BCs: Create / Force / Nodal. b. Enter force for the New Set Name. c. Click on the Input Data button. d. Enter <0 0 1> for Force, and select frequency_depende nt_load for the Time/Freq. Dependent Field. e. Click OK. f. Click on Select Application Region. g. Change the Geometry Filter to FEM. h. Select Node 11 on the bottom right corner of the plate. i. Click Add, and click OK. j. Click Apply.

a

d g

d h i


b e c f

i j WS5-15


b

c a. Hide labels. b. Switch to Iso 3 View. c. Loads/BCs: Plot Markers. d. Under Assigned Load/BC Sets, select Displ_spc1.1 and Force_force. e. Under Select Groups, select default_group. f. Click Apply.

d

e


WS5-16


a


d

b

c


WS5-17


Generate the input file for analysis (cont.). a. Click on Solution Type. b. Select Frequency Response. c. Change the Formulation to Direct. d. Click on Solution Parameters. e. Change the Mass Calculation to Coupled. f. Enter 0.00259 for WtMass Conversion.

e b

f

g. Enter 0.06 for Struct. Damping Coefficient. h. Click OK. i. Click OK.

c d

g

a i h


WS5-18


Generate the input file for analysis (cont.). a. Click on Subcases. b. Select frequency_response from the Available Subcases field. c. Click on Subcase Parameters. d. Click on DEFINE FREQUENCIES button.

d b

g

e. Enter 20 for the start freq., 1000 for the end freq., and 49 for the number of increments. f. Click OK. g. Click OK.

e c a


WS5-19



b d

d c

c

a


WS5-20

g


Generate the input file for analysis (cont.). a. Click on Subcase Select. b. Select frequency_response and unselect Default. c. Click OK. d. Click Apply.

b

b


WS5-21




WS5-22



ID SEMINAR, PROB5 SOL 108 TIME 30 CEND TITLE = FREQUENCY RESPONSE DUE TO UNIT FORCE AT TIP ECHO = UNSORTED SPC = 1 SET 111 = 11, 33, 55 DISPLACEMENT(SORT2, PHASE) = 111 SUBCASE 1 DLOAD = 500 FREQUENCY = 100 $ OUTPUT (XYPLOT) $ XTGRID= YES YTGRID= YES XBGRID= YES YBGRID= YES YTLOG= YES YBLOG= NO XTITLE= FREQUENCY (HZ) YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASE XYPLOT DISP RESPONSE / 11 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASE XYPLOT DISP RESPONSE / 33 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASE XYPLOT DISP RESPONSE / 55 (T3RM, T3IP) $


BEGIN BULK PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $ INCLUDE ’plate.bdf’ $ $ SPECIFY STRUCTURAL DAMPING $ PARAM, G, 0.06 $ $ APPLY UNIT FORCE AT TIP POINT $ RLOAD2, 500, 600, , ,310 $ DAREA, 600, 11, 3, 1.0 $ TABLED1, 310, , 0., 1., 1000., 1., ENDT $ $ SPECIFY FREQUENCY STEPS $ FREQ1, 100, 20., 20., 49 $ ENDDATA

WS5-23


Windows Users:




WS5-24


Unix Users:




WS5-25

Step 9: Review Results


While still editing prob5.f06, search for the word X Y – O U T P U T S U M M A R Y (spaces are necessary) Displacement at Grid 11 Frequency (X)

Displacement (Y)

140

=

___________

380

=

___________


WS5-26

Step 9: Review Results (cont.) Displacement at Grid 33 Frequency (X)

Displacement (Y)

140

=

___________

600

=

___________

Displacement at Grid 55 Frequency (X)

Displacement (Y)

140

=

___________

1000

=

___________


WS5-27

Step 9: Review Results (cont.)



WS5-28

Step 9: Review Results (cont.)

MSC.Nastran users use plotps utility to create a postscript file, prob5.ps, from the binary plot file, prob5.plt.



WS5-29



a

c

d

b


WS5-30


Create a graph of Frequency vs. Displacement. a. Results: Create / Graph / Y vs X. b. Under Select Result case(s), click on frequency_response, 0 of 50 subcases. c. Select All as the Filter Method. d. Click Filter. e. Click Apply. f. Click Close.

a

b c

d

e


f

WS5-31


Create a graph of Frequency vs. Displacement (cont.). a. Select Displacement, Translational for the Select Y Result field. b. Select Z Component as the Quantity. c. Click on the Target Entities icon. d. Change the Target Entity Selection to Nodes. e. Select the bottom right node where the force was applied.

c

d e

a

b f


WS5-32


Create a graph of Frequency vs. Displacement (cont.). a. Click on the Plot Options icon. b. Change Complex No. as to Magnitude. c. Click Apply.


a

b


WS5-33


Create a graph of Frequency vs. Displacement (cont.). a. Change Complex No. as to Phase. b. Click Apply.

Phase Angle at Node 11

Repeat the previous steps to plot nodes 33 and 55.

a

b NAS102, Workshop 5, January 2004 Copyright© 2004 MSC.Software Corporation

WS5-34




WS5-35




WS5-36




WS5-37




WS5-38

WORKSHOP 6 MODAL FREQUENCY RESPONSE ANALYSIS


WS6-1


WS6-2

Workshop 6 – Modal Frequency Response Analysis

Objectives

Define a frequency-varying excitation. Produce an MSC.Nastran input file from the dynamic math model created in Workshop 1. Submit the file for analysis in MSC.Nastran. Compute nodal displacements for desired frequency domain.


WS6-3


Problem Description

Using the modal method, determine the frequency response of the flat rectangular plate, created in Workshop 1, excited by a 0.1 psi pressure load over the total surface of the plate and a 1.0 lb. force at a corner of the tip lagging 45o . Use a modal damping of ξ = 0.03. Use a frequency step of 20 hz between a range of 20 and 1000 hz; in addition, specify five evenly spaced excitation frequencies between the half power points of each resonant frequency between the range of 20-1000 hz. Below is a finite element representation of the flat plate. It also contains the load and boundary constraints. 0.1 psi over the total surface

1.0

Figure 6.1 – Loads and Boundary Conditions NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

WS6-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference a previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Specify modal damping as a tabular function of natural frequency (TABDMP1). 3. Define the frequency-varying pressure loading (PLOAD2, LSEQ, and RLOAD2). 4. Define the frequency-varying tip load (DAREA and RLOAD2). 5. Define a set of frequencies to be used in the solution (FREQ1, FREQ4). 6. Prepare the model for a modal frequency response analysis (SOL 111). 7. Define the dynamic load phase lead modal frequency response (DPHASE). 8. Request response in terms of nodal displacement at Grids 11, 33, and 55. 9. Go to Step 8 for MSC.Patran users.


WS6-5

Workshop 6 – Modal Frequency Response Analysis ID SEMINAR, PROB6 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS6-6

Workshop 6 – Modal Frequency Response Analysis 1

2

3


4

5

6

WS6-7

7

8

9

10

Workshop 6 – Modal Frequency Response Analysis 1

2

3

4

5

6

ENDDATA


WS6-8

7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Create a new database. Import the input file. Create a frequency dependent load case for the frequency response. Create a frequency dependent field for the frequency response. Create a frequency dependent unit force. Create forces. Create an MSC.Nastran input file. Review the MSC.Nastran input file. Submit the model to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. Plot the results.


WS6-9


a

Create a new database named prob6.db. a. File / New. b. Enter prob6 as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


d

e f c

b

WS6-10

g

Step 2. Import the Input File h

a Create the model by importing an existing MSC.Nastran file, plate.bdf. a. Analysis: Read Input File/Model Data. b. Enter prob6 for Job Name. c. Click on Select Input File. d. Select plate.bdf. e. Click OK. f. Click Apply. g. Click OK. h. Click on the Show Labels icon.

d

e

b

c f NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

g WS6-11

Step 3. Create a Frequency Dependent Load Case

a e Create a frequency dependent load case for the frequency response: a. Load Cases: Create. b. Enter frequency_response for Load Case Name. c. Select Time Dependent for Load Case Type. d. Click on Assign/Prioritize Loads/BCs. e. Click on Displ_spc1.1 under Select Individual Loads/BCs. f. Click OK. g. Click Apply.

b c

d

g NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

f WS6-12

Step 4. Create a Frequency Dependent Field

Create a frequency dependent field for the frequency response: a. Fields: Create/Non Spatial/Tabular Input. b. Enter frequency_dependent_lo ad for Field Name. c. Select Frequency (f) under Table Definition. d. Click [Options…]. e. Enter 2 for the Maximum Number of f. f. Click OK. g. Click on Input Data… h. Enter the following values into the Data Table:

i. j.

Freq(f)

Value

10.

1.0

1000.

1.0

a

e

b

f

c

h

g d

Click OK. Click Apply.

j NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

i WS6-13

Step 5. Create a Frequency Dependent Unit Force

In the Loads/BCs menu, a. Create/Pressure/Element Uniform. b. Enter pressure as the New Set Name. c. Select 2D as Target Element Type. d. Click on Input Data… e. Enter –0.1 for Top Surf Pressure. f. Click in the Time/Freq. Dependence box and then click on frequency_dependent_load in the Time/Frequency Dependent Fields Box. g. Click OK. h. Click on Select Application Region… i. Select FEM for Geometry Filter. j. Select Elm 1:40 under Select 2D Elements or Edges. k. Click Add. l. Click OK. m. Click Apply.

a

e

i

f j k g b c

l d h


f

WS6-14

Step 6. Create Forces

a Create forces in the Loads/BCs menu. a. Create/Force/Nodal. b. Enter force for New Set Name. c. Click on Input Data… d. Enter <0,0,1> for Force . e. Select frequency_dependent_lo ad from the Time/Freq. Dependence box. f. Click OK. g. Click on Select Application Region…

d

e

f b

c g


WS6-15

Step 6. Create Forces (cont.) f

g

a

a. Select FEM from the Geometry Filter. b. Click on the Select Nodes box then choose Node 11. c. Click Add. d. Click OK. e. Click Apply. f. Click on the Hide Labels icon. g. Change to Iso 3 View.

b c

d b e NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

WS6-16

Step 6: Create Forces (cont.) e

a Plot the markers of the forces created. a. Action: Plot Markers b. Under Assigned Load/BC Sets, highlight Displ_spc1.1, Press_pressure, Force_force. c. Under Select Groups, highlight default_group. d. Click Apply. The model should resemble the figure to the right. e. Click on the Show Labels icon on the toolbar.

b

c


WS6-17


a Create an input file for analysis: a. Analysis: Analyze/Entire Model/Analysis Deck. b. Enter prob6 for the Job Name. c. Click on Translation Parameters… d. Select XDB and Print for Data Output. e. Click OK. f. Click on Solution Type…

d

b

c f


WS6-18


a. Select Frequency Response. b. Select Modal for Formulation. c. Click Solution Parameters… d. Select Coupled for Mass Calculation and enter 0.00259 for Wt.Mass Conversion. e. Click Eigenvalue Extraction… f. Under Frequency Range of Interest, enter 10 for Lower and 2000 for Upper. g. Click OK. h. Click OK. i. Click OK.

d a

f d

b c

i

e

h g


WS6-19


a

e

b a. Click on Subcases… b. Action: Create c. Select frequency_response from Available Subcases. d. Click Subcase Parameters… e. Click on DEFINE FREQUENCIES… f. Click Add Row. g. Enter: Incr. Type

Start Freq.

End Freq.

No. Incr.

Cluster/ Spread

1

Linear

20

1000

49

Not Used

2

Linear

20

1000

5

Not Used

c

d

g

h. Click OK.

f h NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

WS6-20


a. Select Crit. Damp. (CRIT) from Modal Damping. b. Click on DEFINE MODAL DAMPING… c. Click Add Row. d. Enter: Frequency

Value

1

0

.03

2

10

.03

d a b

e. Click OK. f. Click OK.

c

f

e


WS6-21


a. Click on Output Requests… b. Under Output Requests highlight SPCFORCES(SORT1, Real)=ALLFEM. c. Click Delete. d. Click OK. e. Click Apply. f. Click Cancel.

b

a c

d e


f WS6-22


a. Click Subcases Select… b. Click on Default under Subases Selected to deselect it. c. Click on frequency_response under Subcases for Solution Sequence. d. Click OK. e. Click Apply.

c

b

a e NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

d WS6-23




WS6-24

Step 8. Edit Input File for MSC.Nastran Users

Since the phase lead term in the equation of the dynamic function (DPHASE) is not currently supported by PATRAN, you will need to manually edit the file, prob6.bdf, to insert the appropriate phase for the point load. Search for: RLOAD1

9

1

Insert the identification number of the DPHASE entry in the 5th field. The revised RLOAD1 card should look as follows: RLOAD1

8

8

9

92

1

Also, insert the necessary DPHASE card: DPHASE


92

11

WS6-25

3

-45.

Step 9. Review Input File for MSC.Nastran Users

For MSC.Nastran users who created the input file using a text editor, the input file (prob6.dat) should be similar to the file below: ID SEMINAR, PROB6 SOL 111 TIME 30 CEND TITLE = FREQUENCY RESPONSE WITH PRESSURE AND POINT LOADS SUBTITLE = USING THE MODAL METHOD WITH LANCZOS ECHO = UNSORTED SEALL = ALL SPC = 1 SET 111 = 11, 33, 55 DISPLACEMENT(PHASE, PLOT) = 111 METHOD = 100 FREQUENCY = 100 SDAMPING = 100 SUBCASE 1 DLOAD = 100 LOADSET = 100 $ OUTPUT (XYPLOT) $ XTGRID= YES YTGRID= YES XBGRID= YES YBGRID= YES YTLOG= YES YBLOG= NO XTITLE= FREQUENCY (HZ) YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASE XYPLOT DISP RESPONSE / 11 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASE


WS6-26


XYPLOT DISP RESPONSE / 33 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASE XYPLOT DISP RESPONSE / 55 (T3RM, T3IP) $ BEGIN BULK $ $ PARAMETERS FOR POST-PROCESSING PARAM,COUPMASS,1 PARAM,WTMASS,0.00259 $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $ INCLUDE ’plate.bdf’ $ $ EIGENVALUE EXTRACTION PARAMETERS $ EIGRL, 100, 10., 2000. $ $ SPECIFY MODAL DAMPING $ TABDMP1, 100, CRIT, +, 0., .03, 10., .03, ENDT $ $ APPLY UNIT PRESSURE LOAD TO PLATE $ LSEQ, 100, 300, 400 $ PLOAD2, 400, 1., 1, THRU, 40 $


WS6-27

$ APPLY PRESSURE LOAD $ RLOAD2, 400, 300, , ,310 $ TABLED1, 310, , 10., 1., 1000., 1., ENDT $ $ POINT LOAD $ $ IF 'DAREA' CARDS ARE REFERENCED, THEN $ 'DPHASE' AND 'DELAY' CAN BE USED $ RLOAD2, 500, 600, , 320, 310 $ DPHASE, 320, 11, 3, -45. $ $ DAREA, 600, 11, 3, 1.0 $ $ COMBINE LOADS $ DLOAD, 100, 1., .1, 400, 1.0, 500 $ $ SPECIFY FREQUENCY STEPS $ FREQ1, 100, 20., 20., 49 FREQ4, 100, 20., 1000., .03, 5 $ ENDDATA

Step 10. Submitting the Input File for Analysis

Windows Users:




WS6-28


Unix Users:




WS6-29

Step 11. Review F06 File

MSC.Nastran users use plotps utility to create a postscript file, prob6.ps, from the binary plot file, prob6.plt.


MSC.Patran Users should proceed to step 13.


WS6-30

Step 11. Review the F06 File (cont.)

While still editing prob6.f06, search for the word: X Y – O U T P U T S U M M A R Y (spaces are necessary). Displacement at Grid 11 Frequency (X)

Displacement (Y)

140

=

______________

440

=

______________


Displacement (Y)

140

=

______________

660

=

______________


Displacement (Y)

140

=

______________

1000

=

______________


WS6-31

Step 12. Compare the Results


MSC.Nastran MSC.NastranUsers Usershave havefinished finishedthis thisworkshop. workshop. MSC.Patran MSC.PatranUsers Usersshould shouldproceed proceedto tothe thenext nextstep. step. NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

WS6-32

Step 13. Attach the XDB g

f a

a

Proceed with the Reverse Translation process, that is attaching the prob6.xdb results file to MSC.Patran. To do this, return to the Analysis form and proceed as follows. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click Select Results File. c. Select prob6.xdb. d. Click OK. e. Click Apply. f. Turn off entity labels. g. Select Iso 3 view.

c

d

b


WS6-33

Step 14. Plot the Results

a

Plot the results in XY Plots. The first plot is the Displacement versus Frequency plot at Node 11. In the Results menu: a. Create/Graph/Y vs X b. Select Frequency_response, 0 of 54 from Select Results Case. c. Select All as the Filter Method. d. Click Filter. e. Click Apply. f. Click Close.

b c

d

e


WS6-34

f

Step 14. Plot the Results (cont.)

a. Select Displacement, Translational under Select Y Result. b. Select Z Component for the Quantity. c. Select Global Variable for X. d. Select Frequency for Variable. e. Click on the Plot Options icon. f. Select Magnitude for Complex No. as. g. Click on the Display Attributes icon.

e

g

a f b c d


WS6-35


b

a. Select Log for Y Axis Scale. b. Click on the Target Entities icon. c. Select Node 11 under Select Nodes. d. Click Apply.

c

a c


d

WS6-36

Step 14. Plot the Results (cont.) Displacement Response at Loaded Corner (Node 11)


WS6-37


The second plot is the Displacement versus Frequency at Node 33. a. Click in the Select Nodes box and select Node 33. b. Click Apply.

a

a

b NAS102, Workshop 6, January 2004 Copyright© 2004 MSC.Software Corporation

WS6-38

Step 14. Plot the Results (cont.) Displacement Response at Tip Center (Node 33)


WS6-39


The third plot is the Displacement versus Frequency at Node 55. a. Click in the Select Nodes box and select Node 55. b. Click Apply.

a

a

b


WS6-40

Step 14. Plot the Results (cont.) Displacement Response at Opposite Corner (Node 55)


WS6-41


WS6-42

WORKSHOP 6A MODAL FREQUENCY RESPONSE ANALYSIS

NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-1


WS6A-2

MODAL FREQUENCY RESPONSE

Problem Description

Using the Modal Method, determine the frequency response of the flat rectangular plate, created in Workshop 1a, excited by a 0.1 psi pressure load over the total surface of the plate and a 1.0 lb. force at a corner of the tip lagging 45°. Use a modal damping of ξ = 0.03. Use a frequency step of 20 Hz between a range of 20 and 1000 Hz; in addition, specify five evenly spaced excitation frequencies between the half power points of each resonant frequency between the range of 20-1000 Hz.


WS6A-3


Problem Description (cont.)

Below is a finite element representation of the flat plate. It also contains the loads and boundary constraints.

0.1 psi. over the total surface

1.0


WS6A-4


Suggested Exercise Steps 1. 2. 3. 4. 5. 6. 7. 8.

Import the input file. Create a non-spatial field for the pressure load and the force load. Create a time dependent load case. Create the time dependent force load. Create the time dependent pressure load. Submit the model to MSC.Nastran for analysis. Attach the .XDB results file. Post Process results – create X vs Y graph of displacements.


WS6A-5

CREATE NEW DATABASE

a

d Create a new database called ws6.db. a. File / New. b. Enter ws6A as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


e b

c

f g

WS6A-6

Step 1. File / Import h

a Create the model by importing an existing MSC.Nastran file, plate.bdf. a. Analysis: Read Input File/Model Data. b. Enter prob6A for Job Name. c. Click on Select Input File. d. Select plate.bdf. e. Click OK. f. Click Apply. g. Click OK. h. Click on the Show Labels icon.

d

e

b

c f NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

g WS6A-7

Step 2. Field: Create / Non Spatial / Tabular Input

a

Create a Non Spatial field for the pressure load. a. Field: Create / Non Spatial / Tabular Input. b. Enter pressure for the Field Name. c. Select Frequency (f) as the Active Independent Variable. d. Click Input Data. e. Enter the values showed in the table. f. Click OK. g. Click Apply.

b e c

d

f g NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-8

Step 2. Field: Create / Non Spatial / Tabular Input (Cont.)

Create a Non Spatial field for the force load. a. Field: Create / Non Spatial / Tabular Input. b. Enter force for the Field Name. c. Select Complex as the Scalar Field Type. d. Click Input Data. e. Change the Complex Data Format to Magnitude-Phase (degrees). f. Enter the values showed in the table. g. Click OK. h. Click Apply.

a

e b c f

d g

h NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-9

Step 3. Load Cases: Create

Create a Time Dependent load case. a. Load cases: Create b. Enter modal_freq_response for the Load Case Name. c. Select Time Dependent as the Load Case Type. d. Click Assign/Prioritize Loads/ BCs. e. Click on the Displ_constraint in the Select Individual Loads/BCS field. f. Click OK. g. Click Apply.

a e

b c

d f g NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-10

Step 4. Loads/BCs: Create / Force / Element Uniform

Create the time dependent Force load. a. Loads/BCs: Create / Force / Nodal. b. Enter Force for the New Set Name. c. Click on the Input Data button. d. Enter <0,0,1> for Force, and select force for the Time/Freq. Dependent Field. e. Click OK. f. Click on Select Application Region. g. Change the Geometry Filter to FEM. h. Select the node on the bottom right corner. i. Click Add, and click OK. j. Click Apply.

a d g

h i b e

c f

i j NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-11

Step 5. Loads/BCs: Create / Pressure / Element Uniform

Create the time dependent Pressure load. a. Loads/BCs: Create / Pressure / Element Uniform. b. Enter pressure for the New Set Name. c. Change the Target Element Type to 2D. d. Click on the Input Data button. e. Enter -0.1 for Top Surf Pressure, and select pressure for the Time/Freq. Dependent Field. f. Click OK. g. Click on Select Application Region. h. Select all the elements for the application region. i. Click Add, and click OK. j. Click Apply.

a e

h i b f

c d g

i j


WS6A-12

Step 6. Analysis: Analyze / Entire Model / Full Run

Submit the model for analysis. a. Analysis: Analyze / Entire Model / Full Run. b. Click on Solution Type. c. Select Frequency Response. d. Change the Formulation to Modal. e. Click on Solution Parameter button. f. Select Coupled for Mass Calculation. g. Enter 0.00259 for Wt-Mass Conversion. h. Click OK. i. Click OK.

a

f

c

g d e b i

h


WS6A-13

Step 6. Analysis: Analyze / Entire Model / Full Run (Cont.)

Submit the model for analysis (cont.). a. Click on Subcases. b. Select modal_freq_response from the Available Subcases field. c. Click on Subcase Parameters. d. Click on DEFINE FREQUEYNCIES button.

d b

e. Use the values in the table. f. Click OK.

e

c

a

f NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-14


Submit the model for analysis (cont.). a. Change Modal Damping to Crit. Damping (CRIT). b. Click on DEFINE MODAL DAMPING. c. Enter the values showed in the Define Damping window. d. Click OK. e. Click OK. f. Click Apply (on the Subcase form). g. Click Cancel.

a

c b

e d


WS6A-15


Submit the model for analysis (cont.). a. Click on Subcase Select. b. Select modal_freq_response and unselect Default. c. Click OK. d. Click Apply.

b

c a d NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-16

Step 7. Analysis: Access Results / Attach XDB / Result Entities

Attach the XDB result file. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click on Select Result File. c. Select ws6.xdb. d. Click OK. e. Click Apply.

a

c

d

b

e NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-17

Step 8. Results: Create / Graph / Y vs X

Create a X-Y graph of displacement results. a. Results: Create / Graph / Y vs X. b. Click on SC1:MODAL_FREQ_ RESPONSE. c. Select Global Variable as the Filter Method. d. Click Filter. e. Click Apply. f. Click Close.

a

b

c

d


f WS6A-18

Step 8. Results: Create / Graph / Y vs X (Cont.)

Create a X-Y graph of displacement results (cont.). a. Select Displacement, Translational for the Select Y Result field. b. Select Z Component as the Quantity. c. Click on the Target Entities icon. d. Change the Target Entity Selection to Nodes. e. Select the node where force is applied. f. Click Apply.

c

d e

a

f


WS6A-19

b


Create a X-Y graph of displacement results (cont.). a. Click on Display Attribute. b. Change Y Axis Scale from Linear to Log. c. Click on Plot Option. d. Change the Complex No. as to Magnitude. e. Click Apply.

c a

d b


WS6A-20

Step 8. Results: Create / Graph / Y vs X (Cont.) Displacement Magnitude vs. Frequency Plot


WS6A-21


Create a X-Y graph of phase results. a. Change Complex No. as from Magnitude to Phase. b. Change Y Axis Scale from Log to Linear. c. Click Apply.

aa

b NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-22


Alternative method for plotting phase plot: In the output request, change the displacement results format from Rectangular to Polar. a.

When this method is used, the phase plot can be obtained by using the Magnitude option for the Complex No as.

b.

Click on Apply.

a

b NAS102, Workshop 6A, January 2004 Copyright© 2004 MSC.Software Corporation

WS6A-23


WS6A-24

WORKSHOP 7a DIRECT TRANSIENT RESPONSE WITH BASE EXCITATION

NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-1


WS7a-2

Workshop 7a – Direct Transient Response With Base Excitation

Objectives



WS7a-3


Problem Description

Using the direct method, determine the transient response to a unit acceleration sine pulse of 250Hz applied at the base in the z direction. A large mass of 1000lb is applied to the base. Use structural damping of g=0.06 and convert this damping to equivalent viscous damping at 250Hz. Drive Point



WS7a-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Modify base constraints and release displacements in the Z-direction. 3. Define the time-varying unit acceleration (TLOAD2 and DAREA). 4. Create an RBE2 to tie the left edge to the drive point. 5. Specify the structural damping and convert this damping to equivalent viscous damping. z PARAM, G, 0.06 z PARAM, W3, 1571.0 6. Specify integration time steps (TSTEP). 7. Prepare the model for a direct transient analysis (SOL 109). 8. Request response in terms of nodal displacement at grids 11, 33, and 55. 9. Generate an input file and submit it to the MSC.Nastran solver for enforced motion using direct transient analysis. 10. Review the results, specifically the nodal displacements, velocities, and acceleration.


WS7a-5

Workshop 7a – Direct Transient Response With Base Excitation ID SEMINAR, PROB7A _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS7a-6

Workshop 7a – Direct Transient Response With Base Excitation 1

2

3


4

5

6

WS7a-7

7

8

9

10

Workshop 7a – Direct Transient Response With Base Excitation 1

2

3

4

5

6

ENDDATA


WS7a-8

7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Create a new database. Import an existing model. Create a load case. Create a RBE2. Create time dependent fields. Create load/boundary conditions. Create a MSC.Nastran input file. Review the MSC.Nastran input file. Submit the input file to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. View results.


WS7a-9


a

d Create a new database named prob7a.db. a. File / New. b. Enter prob7a as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


e f b

c

WS7a-10

g


e

f

a b

c

c

Import the model from a Nastran Input File. a. File / Import. b. Select MSC.Nastran Input as the Source. c. Select plate.bdf and click Apply. d. Click OK when the Nastran Input File Import Summary appears. e. Click Show Labels. f. Switch to Iso 3 View.

d d NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-11



a e

b c

d

f g NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-12

Step 4. Create a RBE2

Create a RBE2 to tie the left edge to the drive point. a. Elements: Create / MPC / RBE2. b. Click Define Terms. c. Turn Auto Execute off. d. Choose UZ as the DOF for the Dependent Nodes. e. Select 4 nodes on the left edge of the plate, excluding the center node (Nodes 1, 12, 34 and 35). f. Click Apply. g. Select the center node on the left edge of the plate (Node 23). h. Click Apply. i. Click Cancel. j. Click Apply.


a

b j c g

e d

h

i

WS7a-13

f


Create a time-dependent non-spatial field. a. Fields: Create / Non Spatial / Tabular Input b. Enter time_dependent_acceleration for the Field Name. c. Click [Options…]. d. Enter 41 for Maximum Value of t. e. Click OK.

a

b d

e


WS7a-14

c



h

i

g

j

f


WS7a-15



k

l

m NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-16


Create the time-dependent unit acceleration. a. Loads/BCs: Create / Acceleration / Nodal. b. Enter unit_acceleration for the New Set Name. c. Click on the Input Data button. d. Enter <0, 0, 1.0> for Trans. Accel., and select time_dependent_acc eleration for the Time/Freq. Dependent Field. e. Click OK. f. Click on Select Application Region. g. Choose FEM h. Select the center node on the left side of the plate (Node 23). i. Click Add, and click OK. j. Click Apply.

a

d

d

g

h i


b e

c i

f j WS7a-17


a

Modify the original constraint from the imported database. a. Loads/BCs: Modify / Displacement / Nodal. b. Click on spc1.1 in the Select Set to Modify box to select it. c. Click on the Modify Data button. d. Modify Translations to <0,0,>. e. Click OK. f. Click Apply.

d

b

e

e c f NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-18


a

Generate the input file for analysis. a. Analysis: Analyze / Entire Model / Analysis Deck. b. Enter prob7a as the Job Name. c. Click Translation Parameters. d. Check XDB and Print. e. Click OK.

d

b

c

e NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-19


Generate the input file for analysis (cont.). a. Click on Solution Type. b. Select Transient Response. c. Change the Formulation to Direct. d. Click on Solution Parameters. e. Change the Mass Calculation to Coupled. f. Enter 0.00259 for WtMass Conversion.

e

b f

g. Enter 0.06 for Struct. Damping Coefficient and 1571 for W3, Damping Factor. h. Click OK. i. Click OK.

i

h NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

c d

g

WS7a-20

a



d b

g

e. Change No. of Time Steps to 200, and Delta-T to 0.0002. f. Click OK. g. Click OK.

e c a

f NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-21


Generate the input file for analysis (cont.). a. Click on Output Requests. b. Under Output Requests, select SPCFORCES(SORT2, REAL)=All FEM and click Delete. c. Under Select Result Type, select Velocities and Accelerations. d. Click OK. e. Click Apply. f. Click Cancel.

c

b

a b

d NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-22

e

f



b

b

c a d NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-23


An MSC.Nastran input file called prob7a.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to step 9.


WS7a-24


For MSC.Nastran users who created the input file using a text editor, the input file (prob7a.dat) should be similar to the file below:

ID SEMINAR, PROB7A SOL 109 TIME 30 CEND TITLE = TRANSIENT RESPONSE WITH BASE EXCITATION SUBTITLE = USING DIRECT TRANSIENT METHOD, NO REDUCTION ECHO = UNSORTED SPC = 200 SET 111 = 23, 33 DISPLACEMENT (SORT2) = 111 VELOCITY (SORT2) = 111 ACCELERATION (SORT2) = 111 SUBCASE 1 DLOAD = 500 TSTEP = 100 $ OUTPUT (XYPLOT) XGRID=YES YGRID=YES XTITLE= TIME (SEC) YTITLE= BASE ACCELERATION XYPLOT ACCELERATION RESPONSE / 23 (T3) YTITLE= BASE DISPLACEMENT XYPLOT DISP RESPONSE / 23 (T3) YTITLE= TIP CENTER DISPLACEMENT RESPONSE XYPLOT DISP RESPONSE / 33 (T3) $ BEGIN BULK $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $


INCLUDE ’plate.bdf’ PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $ $ SPECIFY STRUCTURAL DAMPING $ PARAM, G, 0.06 PARAM, W3, 1571. $ $ APPLY EDGE CONSTRAINTS $ SPC1, 200, 12456, 1, 12, 23, 34, 45 SPCI, 200, 3, 23 $ $ $ RBE MASS TO REMAINING BASE POINTS $ RBE2, 101, 23, 3, 1, 12, 34, 45 $ $ APPLY LOADING TO FOUNDATION MASS $ TLOAD2, 500, 600, , A, 0.0, 0.004, 250., -90. $ SPCD, 600, 23, 3, 1.0 $ $ SPECIFY INTEGRATION TIME STEPS $ TSTEP, 100, 200, 2.0E-4, 1 $ ENDDATA

WS7a-25


Windows Users:


Double click on MSC.Nastran icon. Select prob7a.bdf or prob7a.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


WS7a-26


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob7a.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob7a scr=yes. Monitor the run using the UNIX ps command.


WS7a-27


MSC.Nastran users use plotps utility to create a postscript file, prob7a.ps, from the binary plot file, prob7a.plt.

When the run is completed, edit the prob7a.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.

While still editing prob7a.f06, search for the word D I S P L (spaces are necessary) Displacement at Grid 23 Time

T3

0

= ___________

.02

= ___________

.04

= ___________


WS7a-28


T3

0

= ___________

.02

= ___________

.04

= ___________

Now search for the word V E L O C (spaces are necessary) Velocity at Grid 23 Time

T3

0

= ___________

.02

= ___________

.04

= ___________


WS7a-29

Step 10: Review F06 File (cont.) Velocity at Grid 33 Time

T3

0

= ___________

.02

= ___________

.04

= ___________

Now search for the word A C C E L (spaces are necessary) Acceleration at Grid 23 Time

T3

0

= ___________

.02

= ___________

.04

= ___________


WS7a-30

Step 10: Review F06 File (cont.) Acceleration at Grid 33 Time

T3

0

= ___________

.02

= ___________

.04

= ___________


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WS7a-32



WS7a-33


MSC.Nastran MSC.NastranUsers Usershave havefinished finishedthis thisworkshop. workshop. MSC.Patran MSC.PatranUsers Users should shouldproceed proceedto tothe thenext nextstep. step. NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

WS7a-34


Attach the XDB result file. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click on Select Results File. c. Select prob7a.xdb. d. Click OK. e. Click Apply.

a

c

d

b


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a

b c

d

f

e


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Create a X-Y graph of displacement results (cont.). a. Select Displacement, Translational for the Select Y Result field. b. Select Z Component as the Quantity. c. Click on the Target Entities icon. d. Change the Target Entity Selection to Nodes. e. Select the center node on the left edge of the plate (Node 23). f. Click Apply.

c

d e

a

b f


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Base Displacement at Node 23


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Create a X-Y graph of displacement results (cont.). a. Select the center node on the right edge of the plate (Node 33). b. Click Apply.

Tip Displacement at Node 33

a

b


WS7a-39


Create a X-Y graph of displacement results (cont.). a. Click Select Results. b. Under Select Y Result, select Velocities, Translational. c. Click on the Target Entities icon. d. Select the center node on the left edge of the plate (Node 23). e. Click Apply.

a

c

d

b

e


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Base Velocity at Node 23


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Tip Velocity at Node 33

a

b


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Create a X-Y graph of displacement results (cont.). a. Click Select Results. b. Under Select Y Result, select Accelerations, Translational. c. Click Target Entities. d. Select the center node on the left edge of the plate (Node 23). e. Click Apply.

a

c

d

b

e


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Base Acceleration at Node 23


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Tip Acceleration at Node 33

a

b NAS102, Workshop 7a, January 2004 Copyright© 2004 MSC.Software Corporation

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WORKSHOP 8a ENFORCED MOTION WITH DIRECT FREQUENCY RESPONSE


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WS8a-2

Workshop 8 – Enforced Motion with Direct Frequency Response

Objectives

Define frequency-varying tip displacement. Produce an MSC.Nastran input file from a dynamic math model created in Workshop 1. Submit the file for analysis in MSC.Nastran. Compute nodal displacements for desired time domain.


WS8a-3


Problem Description

Using the direct method, determine the frequency response of the flat rectangular plate, created in Workshop 1, under a 0.1 displacement at a corner of the tip. Use a frequency step of 20 Hz in the range of 20 to 1000 Hz. Use a structure damping of g = 0.06.

Below is a finite element representation of the flat plate. It also contains the loads and boundary constraints.

0.1

Figure 8.1 – Loads and Boundary Conditions NAS102, Workshop 8a, January 2004 Copyright© 2004 MSC.Software Corporation

WS8a-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference a previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Define the frequency-varying tip displacement (RLOAD2, TABLED1, SPCD). 3. Define a set of frequencies to be used in the solution (FREQ1). 4. Prepare the model for a direct frequency analysis (SOL108). 5. Specify the structural damping. z PARAM, G, 0.06

6. Request response in terms of nodal displacement and grid points 11, 33, and 55. 7. Generate an input file. 8. Go to Step 7 for MSC.Patran users.


WS8a-5

Workshop 8 – Enforced Motion with Direct Frequency Response ID SEMINAR, PROB8A _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 8 – Enforced Motion with Direct Frequency Response 1

2

3


4

5

6

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7

8

9

10

Workshop 8 – Enforced Motion with Direct Frequency Response 1

2

3

4

5

6

ENDDATA


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7

8

9

10


MSC.Nastran MSC.NastranUsers Usersshould shouldgo goto toStep Step7. 7.

MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Create a new database. Import the input file. Create a frequency dependent load case. Create a frequency dependent field for the frequency dependent load. Create a frequency dependent unit force. Create an MSC.Nastran input file. Submit the model to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. Plot the results.


WS8a-9


a

Create a new database named prob8a.db. a. File / New. b. Enter prob8a as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


d

e f c

b

WS8a-10

g

Step 2. Import the Input File h

a Create the model by importing an existing MSC.Nastran file, plate.bdf. a. Analysis: Read Input File/Model Data. b. Enter prob8a for Job Name. c. Click on Select Input File. d. Select plate.bdf. e. Click OK. f. Click Apply. g. Click OK. h. Click on the Show Labels icon.

d

e

b

c f NAS102, Workshop 8a, January 2004 Copyright© 2004 MSC.Software Corporation

g WS8a-11

Step 3. Create a Frequency Dependent Load Case

a e a. Load Cases: Create. b. Enter frequency_response for Load Case Name. c. Select Time Dependent for Load Case Type. d. Click on Assign/Prioritize Loads/BCs. e. Click on Displ_spc1.1 under Select Individual Loads/BCs. f. Click OK. g. Click Apply.

b c

d

g NAS102, Workshop 8a, January 2004 Copyright© 2004 MSC.Software Corporation

f WS8a-12

Step 4. Create a Frequency Dependent Field

Create a frequency dependent field for the frequency dependent load: a. Fields: Create/Non Spatial/Tabular Input. b. Enter frequency_dependent_lo ad for Field Name. c. Select Frequency (f) under Table Definition. d. Click [Options…]. e. Enter 2 for the Maximum Number of f. f. Click OK. g. Click on Input Data… h. Enter the following values into the Data Table:

i. j.

Freq(f)

Value

10.

1.0

1000.

1.0

a

e

b

f

c h g d

Click OK. Click Apply.

j NAS102, Workshop 8a, January 2004 Copyright© 2004 MSC.Software Corporation

i WS8a-13

Step 5. Create a Frequency Dependent Unit Force

In the Loads/BCs menu, a. Create/Displacement/Nodal. b. Enter pt1_disp as the New Set Name. c. Click on Input Data… d. Enter <0 0 0.1> for Spatial Dependence/Translations. e. Select f:frequency_dependent_load from the Time/Freq. Dependence box. f. Click OK. g. Click Select Application Region… h. Select FEM from Geometry Filter. i. Click the Select Nodes box and click on Node 11. j. Click Add. k. Click OK. l. Click Apply.

a d

h

e i j f

b k c g l


e

WS8a-14


a Create an input file for analysis: a. Analysis: Analyze/Entire Model/Analysis Deck. b. Enter prob8a for the Job Name. c. Click on Translation Parameters… d. Select XDB and Print for Data Output. e. Click OK. f. Click on Solution Type…

d

b

c f


WS8a-15


a. Select Frequency Response. b. Select Direct for Formulation. c. Click Solution Parameters… d. Select Coupled for Mass Calculation and enter 0.00259 for Wt.Mass Conversion. e. Enter 0.06 for Struct. Damping Coefficient. f. Click OK. g. Click OK. h. Click on Subcases…

d a d

b c

e h

g f NAS102, Workshop 8a, January 2004 Copyright© 2004 MSC.Software Corporation

WS8a-16


a

a a. Action: Create. b. Select frequency_response from Available Subcases. c. Click Subcase Parameters… d. Click on DEFINE FREQUENCIES… e. Enter the following: Start Freq. = 20 End Freq. = 1000 No. Incr. = 49 f. Click OK. g. Click on Ouput Requests…

e

b

f

d c g


WS8a-17


a. Highlight SPCFORCES(SORT1,Re al)=ALLFEM under Output Requests. b. Click Delete. c. Click OK. d. Click Apply under Subcases. e. Click Cancel under Subcases. f. Click Subcase Select… g. Click on Default under Subcases Selected to delete it. h. Click on frequency_response under Subcases for Solution Sequence: 108. i. Click OK. j. Click Apply.

h

a

g

b i c

f j


WS8a-18


An MSC.Nastran input file called prob8a.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to Step 8.


WS8a-19



ID SEMINAR, PROB8 SOL 108 TIME 30 CEND TITLE= FREQUENCY RESPONSE DUE TO .1 DISPLACEMENT AT TIP SUBTITLE= DIRECT METHOD ECHO= UNSORTED SPC= 1 SET 111= 11, 33, 55 DISPLACEMENT(PHASE, SORT2)= 111 SDISP(PHASE, SORT2)= ALL set 222 = 11 OLOAD= 222 SUBCASE 1 DLOAD= 500 FREQUENCY= 100 $ OUTPUT (XYPLOT) $ $ XTGRID= YES YTGRID= YES XBGRID= YES YBGRID= YES YTLOG= YES YBLOG= NO XTITLE= FREQUENCY (HZ) YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASE XYPLOT DISP RESPONSE / 11 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASE XYPLOT DISP RESPONSE / 33 (T3RM, T3IP)


YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASE XYPLOT DISP RESPONSE / 55 (T3RM, T3IP) $ BEGIN BULK $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $ INCLUDE ’plate.bdf’ PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $ $ SPECIFY STRUCTURAL DAMPING $ PARAM, G, 0.06 $ $ APPLY UNIT DISPLACEMENT AT TIP POINT $ $ RLOAD2, 500, 600, , ,310, , D $ TABLED1, 310, ,0., 1., 1000., 1., ENDT $ SPCD, 600, 11, 3, 0.1 $ $ SPECIFY FREQUENCY STEPS $ FREQ1, 100, 20., 20., 49 $ ENDDATA

WS8a-20


Windows Users:




WS8a-21


Unix Users:




WS8a-22


When the run is completed, use plotps utility to create a postscript file, prob8a.ps, from the binary plot file prob8a.plt.

Edit the prob8a.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.

MSC.Patran Users should proceed to Step 11.


WS8a-23

Step 9. Review the F06 File (cont.)

While still editing prob8a.f06, search for the word: X Y – O U T P U T S U M M A R Y (spaces are necessary). Displacement at Grid 11 Frequency (X)

Displacement (Y)

140

=

______________

380

=

______________


Displacement (Y)

140

=

______________

600

=

______________


Displacement (Y)

140

=

______________

1000

=

______________


WS8a-24





WS8a-25

Step 11. Attach the XDB

a

a

Proceed with the Reverse Translation process, that is attaching the prob8a.xdb results file to MSC.Patran. To do this, return to the Analysis form and proceed as follows. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click Select Results File. c. Select prob8a.xdb. d. Click OK. e. Click Apply.

c

d

b


WS8a-26


a c Plot the results in XY Plots. The first plot is the Displacement versus Frequency plot at Node 11. In the Results menu: a. Results: Create/Graph/Y vs X b. Select Frequency_response, 0 of 50 from Select Results Case. c. Select All as the Filter Method. d. Click Filter. e. Click Apply. f. Click Close.

b

d

e


WS8a-27

f


a. Select Displacement, Translational under Select y Result. b. Select Z Component for the Quantity. c. Select Global Variable for X. d. Select Frequency for Variable. e. Click on the Plot Options icon. f. Select Magnitude for Complex No. as. g. Click on the Target Entities icon. h. Select Node 11 in the Select Nodes box. i. Click Apply.

g

e

h a f b c d i h


WS8a-28

Step 12. Plot the Results (cont.) The Displacement versus Frequency plot at Node 11 should resemble the graph below:


WS8a-29


a

Next plot the Phase versus Frequency. a. Click on the Plot Options icon. b. Select Phase for Complex No. as. c. Click Apply.

b

c NAS102, Workshop 8a, January 2004 Copyright© 2004 MSC.Software Corporation

WS8a-30


Repeat the above steps of plotting the XY plots for Nodes 33 and 55. a. Click on the Plot Options icon. b. Select Magnitude for Complex No. as. c. Click the Target Entities icon. d. Select Node 33. e. Click Apply.

c

a

d

d b

e


WS8a-31



WS8a-32


Next plot the Phase versus Frequency for Node 33. a. Click on the Plot Options icon. b. Select Phase for Complex No. as. c. Click Apply.

a

b


WS8a-33


a. Click on the Plot Options icon. b. Select Magnitude for Complex No. as. c. Click the Target Entities icon. d. Select Node 55. e. Click Apply.

c

a

d d

b

e


WS8a-34



WS8a-35


Finally, plot the Phase versus Frequency for Node 55. a. Click on the Plot Options icon. b. Select Phase for Complex No. as. c. Click Apply.

a

b


WS8a-36

WORKSHOP 9a Response Spectra

Response

Resonant Frequency (Hz)


WS9a-1


WS9a-2

Workshop 9a – Response Spectra

Objectives

Generate the shock spectrum. Submit the file for analysis in MSC.Nastran. Generate the shock spectrum using the direct method.


WS9a-3


Model Description

Define the shock response of the plate due to a 2.0 in/sec2 sine pulse applied at the clamped edge. Use modes to a frequency of 1000Hz with 3% critical damping. Use the SRSS option for model response summation.

Figure 9a.1 Model Description and Loading Diagram NAS102, Workshop 9a, January 2004 Copyright© 2004 MSC.Software Corporation

WS9a-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Generate the finite element representation of the model using (GRID) and (CMASS2) elements. 2. Apply loading to mass, (TLOAD2) and (DAREA). 3. Specify integration time steps (TSTEP). 4. Define frequency and damping values for the SDOF oscillators (DTI). 5. Specify damping information (FREQ) and natural frequency (FREQ1). 6. Define the parameter to calculate shock spectrum. z PARAM, RESPECTRA, 0

7. Generate an input file and submit it to the MSC.Nastran solver for direct transient analysis. 8. Review the results.


WS9a-5

Workshop 9a – Response Spectra ID SEMINAR, PROB9A _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS9a-6

Workshop 9a – Response Spectra 1

2

3


4

5

6

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7

8

9

10

Workshop 9a – Response Spectra 1

2

3

4

5

6

ENDDATA


WS9a-8

7

8

9

10

Step 1: Generate and Review Input File

MSC.Nastran users who created the input file using a text editor, the input file (prob9a.dat) should be similar to the file below:

ID SEMINAR, PROB9A SOL 109 TIME 30 CEND TITLE= TRANSIENT RESPONSE SUBTITLE= USING DIRECT TRANSIENT METHOD LABEL= SHOCK SPECTRUM CALCULATION ECHO= UNSORTED SPC= 100 SET 111= 3000 DISPLACEMENT (SORT2)= 111 $ AT LEAST DISP AND VEL MUST APPEAR VELOCITY (SORT2)= 111 ACCELERATION= 111 DLOAD= 500 TSTEP= 100 $ OUTPUT (XYPLOT) $ $ SHOCK RESPONSE IS ONLY AVAILABLE IN PLOT OR PUNCH OUTPUT. THEREFORE, $ THE ‘OUTPUT(XYPLOT)’ SECTION OF THE CASE CONTROL MUST BE USED. $ XGRID=YES YGRID=YES XYPLOT ACCE / 3000(T1) XLOG= YES YLOG= YES $ $ RELATIVE SHOCK RESPONSES ARE CONTAINED IN THE IMAGINARY/PHASE $ COMPONENTS OF THE OUTPUT $ ABSOLUTE SHOCK RESPONSES ARE CONTAINED IN THE REAL/MAGNITUDE $ COMPONENTS OF THE OUTPUT


$ XTITLE= FREQUENCY (CYCLES/SEC) YTITLE= RELATIVE DISPLACEMENT XYPLOT DISP SPECTRAL 1 / 3000 (T1IP) YTITLE= RELATIVE VELOCITY XYPLOT VELOCITY SPECTRAL 1 / 3000 (T1IP) YTITLE= ABSOLUTE ACCELERATION XYPLOT ACCELERATION SPECTRAL 1 / 3000 (T1RM) $ $ PUNCH SHOCK SPECTRUM FOR LATER USE $ XYPUNCH ACCELERATION SPECTRAL 1 / 3000(T1RM) $ BEGIN BULK $ $ DEFINE GRID POINT $ GRID, 3000, ,0.,0.,0., ,23456 $ $ DEFINE MASS $ CMASS2, 100, 1.0, 3000, 1 $ $ APPLY LOADING TO MASS $ TLOAD2, 500, 600, , 0, 0., 0.004, 250., -90. $ DAREA, 600, 3000, 1, 1. $ $ SPECIFY INTEGRATION TIME STEPS $ TSTEP, 100, 100, 4.0E-4, 1 $ $ PARAMETER TO CALCULATE SHOCK SPECTRUM $ PARAM, RSPECTRA, 0

WS9a-9

Step 1: Generate and Review Input File (cont.) $ $ SPECIFY FREQUENCY AND DAMPING VALUES FOR $ THE SDOF OSCILLATORS AT GRID 3000 $ DTI, SPSEL, 0 DTI, SPSEL, 1, 111, 222, 3000 $ 1= SUBCASE... 111= DAMPING... 222= FREQUENCIES... 3000= GRID NUMBER $ $ DAMPING INFORMATION FOR OSCILLATORS $ FREQ, 111, 0., 0.02, 0.04 $ $ NATURAL FREQUENCIES OF OSCILLATORS $ FREQ1, 222, 20., 20., 49 $ ENDDATA


WS9a-10


Windows Users:




WS9a-11


Unix Users:




WS9a-12

Step 3: View Results

When the run is completed, use the plotps utility to create a postscript file, prob9a.ps, from the binary plot file prob9a.plt. The nonlinear force and displacement plots are shown on the following pages.



WS9a-13

Step 3: View Results (cont.)

Compare the plots from the exercise with those of the following pages:


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WS9a-17


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WORKSHOP 9b Response Spectra (cont.)

Response

Resonant Frequency (Hz)

NAS102, Workshop 9b, January 2004 Copyright© 2004 MSC.Software Corporation

WS9b-1


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Workshop 9b – Response Spectra (cont.)

Objectives

Apply the shock spectrum. Submit the file for analysis in MSC.Nastran. Calculate the shock response using SOL 103.


WS9b-3


Model Description

Define the shock response of the plate due to a 2.0 in/sec2 sine pulse applied at the clamped edge. Use modes to a frequency of 1000Hz with 3% critical damping. Use the SRSS option for model response summation.

Figure 9b.1 Model Description and Loading Diagram NAS102, Workshop 9b, January 2004 Copyright© 2004 MSC.Software Corporation

WS9b-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1.

Reference a previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Modify the boundary conditions for clamped nodes. 3. Place big foundation mass (BFM) at base to simulate ‘clamped’ nodes (CMASS2). 4. RBE mass to remaining base point (RBE2). 5. Identify excitation DOFs (SUPORT). 6. Specify damping tables (TABDMP1). 7. Specify shock spectrum to be used (DLOAD). 8. Specify shock tables. 9. Insert punch output for shock spectrum calculation. 10. Specify the appropriate parameters. z PARAM, SCRSPEC, 0 z PARAM, OPTION, SRSS z PARAM, LFREQ, 0.1 z PARAM, HFREQ, 1000 11. Generate an input file and submit it to the MSC.Nastran solver (SOL 103). 12. Review the results.


WS9b-5

Workshop 9b – Response Spectra (cont.) ID SEMINAR, PROB9B _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 9b – Response Spectra (cont.) 1

2

3


4

5

6

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7

8

9

10

Workshop 9b – Response Spectra (cont.) 1

2

3

4

5

6

ENDDATA


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7

8

9

10


MSC.Nastran users who created the input file using a text editor, the input file (prob9b.dat) should be similar to the file below:

ID SEMINAR, PROB9B SOL 103 TIME 30 CEND TITLE= RESPONSE SPECTRUM ANALYSIS SUBTITLE= USING CALCULATED SHOCK RESPONSE LABEL= SHOCK WILL BE INPUT IN Z DIRECTION ECHO= UNSORTED SET 111= ALL DISPLACEMENT= 111 SPC= 200 SUBCASE 1 METHOD= 100 SDAMP= 200 DLOAD= 500 $ BEGIN BULK $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $ INCLUDE ’plate.bdf’ PARAM,COUPMASS,1 PARAM,WTMASS,0.00259 $ $ BOUNDARY CONDITIONS FOR `CLAMPED’ MODES $ SPC1, 200, 1245, 1, 12, 23, 34, 45 $ $ PLACE BIG FOUNDATION MASS (BFM) AT BASE $ TO STIMULATE `CLAMPED’ MODES $ CMASS2, 110, 1000., 23, 3 $ $ RBE MASS TO REMAINING BASE POINTS $ RBE2, 101, 23, 3, 1, 12, 34, 45


$ $ SUPPORT CARD TO IDENTIFY EXCITATION DOFS $ SUPORT, 23, 3 $ $ EIGENVALUE EXTRACTION $ MUST BE MASS NORMALIZED (DEFAULT) $ EIGR, 100, MGIV, 0., 1000. $ $ TABLE TO SPECIFY DAMPING FOR USE IN THE ANALYSIS $ TABDMP1, 200, CRIT, , 0., 0.03, 1000., 0.03, ENDT $ $ SPECIFICATION OF SHOCK SPECTRUM TO BE USED $ DLOAD, 500, 1.0, 2.0, 1 $ $ DLOAD, ID, OVERALL SCALE, SCALE FOR R-SET DOF# 1, SHOCK TABLE FOR DOF# 1, $ SCALE FOR R-SET DOF# 2, SHOCK TABLE FOR DOF# 2, ETC. $ $ SELECT SHOCK RESPONSE CALCULATION $ PARAM, SCRSPEC, 0 $ $ SELECT SUMMATION OPTION $ PARAM, OPTION, SRSS $ $ MODAL FREQUENCY RANGE CAN BE SELECTED USING PARAM, LFREQ, 0.1 PARAM, HFREQ, 1000. $ $ SPECIFICATION FOR SHOCK TABLES

WS9b-9

Step 1: Generate and Review Input File (cont.) $ DTI, SPECSEL, 0 DTI, SPECSEL, 1, , A, 2, 0., 3, 0.02, , 4, 0.04, ENDREC $ $ DTI, SPECSEL, SHOCK TABLE NUMBER, , [(A)CCELERATION, (V)ELOCITY, OR (D)ISP], $ TABLED1 POINTER, DAMPING FOR TABLE, ETC. $ $ PUNCH OUTPUT FOR SHOCK SPECTRUM CALCULATION $ $ ACCE 4 3000 3 1 $ 0.000000E+00 $ TABLED1 2 20. .038683 40. .152539 60. .33511 80. .576059 100. .862049 120. 1.17619 140. 1.50169 160. 1.82018 180. 2.11404 200. 2.36801 220. 2.56617 240. 2.70027 260. 2.76275 280. 2.75073 300. 2.74632 320. 2.61887 340. 2.4218 360. 2.39068 380. 2.24931 400. 2.02296 420. 1.78538 440. 1.70355 460. 1.57056 480. 1.40493 500. 1.22608 520. 1.20483 540. 1.17631 560. 1.14097 580. 1.10048 600. 1.05582 620. 1.00818 640. .958761 660. .908725 680. .859158 700. .827667 720. .782127 740. .728996 760. .694088 780. .668602 800. .635044 820. .598496 840. .571831 860. .563072 880. .550499 900. .528854 920. .509281 940. .500534 960. .498016 980. .488793 1000. .468321 ENDT $ACCE 4 3000 3 52 $ 2.0000000E-02 TABLED1 3 20. .037708 40. .143365 60. .314936 80. .541342 100. .80976 120. 1.10506 140. 1.40671 160. 1.69567 180. 1.98167 200. 2.22217 220. 2.35249 240. 2.53055 260. 2.56231 280. 2.55577 300. 2.58668 320. 2.45921 340. 2.29411 360. 2.25956 380. 2.12901 400. 1.92605 420. 1.68656 440. 1.61355 460. 1.4968 480. 1.35263 500. 1.19796 520. 1.17707 540. 1.14947 560. 1.11613 580. 1.07807 600. 1.03637 620. .992124 640. .946383 660. .900171 680. .854434 700. .810016 720. .767647 740. .727923 760. .691288 780. .658039 800. .628311


WS9b-10

Step 1: Generate and Review Input File (cont.) 820.

.602091 840. 900. .526973 980. .474171 $ACCE 4 3000 $ 4.0000000E-02 TABLED1 4 20. .039336 100. .764891 180. 1.85678 260. 2.39929 340. 2.17923 420. 1.62279 500. 1.17212 $ 580. 1.05768 600. 660. .892143 740. .731968 820. .611319 900. .532205 980. .469568 $ ENDDATA


.579207 860. .559362 880. .542128 920. .51329 940. .500403 960. .487602 1000. .459408 ENDT 3 103

40. 120. 200. 280. 360. 440. 520.

.137673 1.04406 2.10175 2.42782 2.14283 1.53417 1.15165

60. 140. 220. 300. 380. 460. 540.

.297382 1.31588 2.19165 2.44263 2.0227 1.43168 1.12513

80. 160. 240. 320. 400. 480. 560.

.511244 1.58461 2.3921 2.317 1.8407 1.30597 1.09349

1.01868 680. 760. 840. 920. 1000.

620. .849752 .69746 .588261 .516369 .452243

.977462 700. 780. 860. 940. ENDT

640. .808538 .665814 .567655 .501047

.934986 720. 800. 880. 960.

.769114 .637115 .549125 .485644

WS9b-11


Windows Users:


Double click on MSC.Nastran icon. Select prob9b.bdf or prob9b.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


WS9b-12


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob9b.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob9b scr=yes. Monitor the run using the UNIX ps command.


WS9b-13


When the run is completed, edit the prob9b.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.


WS9b-14


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


WS9b-15



WS9b-16



WS9b-17


WS9b-18

WORKSHOP 10A RANDOM ANALYSIS


WS10A-1


WS10A-2

Workshop 10A – Random Analysis

Objectives

Define a frequency-varying excitation. Define load set power spectral density functions. Produce a MSC.Nastran input file from a dynamic math model created in Workshop 1. Submit the file for random analysis in MSC.Nastran. Compute nodal displacements for desired frequency domain.


WS10A-3


Problem Description

For the plate model, enforce a base motion in the z-direction described by the following power spectral density, (PSD). Autospectra of the Base Excitation


Frequency

G2/Hz

20

0.1

30

1

100

1

500

0.1

1000.

0.1

WS10A-4


Use the modal method with a large mass attached to the edge with an RBE2 entry. Determine: The response displacement and acceleration PSD at the drive location, (the large mass). The displacement PSD at the corner and center of the free edge, (Grids 33 and 55). Use modal solution. Assume a constant critical damping ratio of 3% across the whole frequency range.


WS10A-5


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference a previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Attach the large mass to the edge of the plate (CONM2 and RBE2). 3. Specify modal damping as a tabular function of natural frequency (TABDMP1). 4. Define the frequency-varying tip load (DAREA and RLOAD2). 5. Define a set of frequencies to be used in the solution (FREQ, FREQ1, and FREQ4). 6. Specify Spectral Density (RANDPS and TABRND1). 7. Prepare the model for a direct transient analysis (SOL111). 8. Request acceleration responses at base, tip center, and opposite corner. 9. Generate an input file and submit it to the MSC.Nastran solver for direct transient analysis. 10. Review the results.


WS10A-6

Workshop 10A – Random Analysis ID SEMINAR, PROB10A _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS10A-7

Workshop 10A – Random Analysis 1

2

3


4

5

6

WS10A-8

7

8

9

10

Workshop 10A – Random Analysis 1

2

3

4

5

6

ENDDATA


WS10A-9

7

8

9

10

Step 1. Review the Input File for MSC.Nastran Users

For MSC.Nastran users who created the input file using a text editor, the input file (prob10A.dat) should be similar to the file below: ID SEMINAR, PROB10 SOL 111 TIME 30 CEND TITLE= RANDOM ANALYSIS - BASE EXCITATION SUBTITLE= USING THE MODAL METHOD WITH LANCZOS ECHO= UNSORTED SPC= 101 SET 111= 33, 55, 9999 ACCELERATION(SORT2, PHASE)= 111 METHOD= 100 FREQUENCY= 100 SDAMPING= 100 RANDOM= 100 DLOAD= 100 $ OUTPUT(XYPLOT) XTGRID= YES YTGRID= YES XBGRID= YES YBGRID= YES YTLOG= YES XTITLE= FREQUENCY YTTITLE= ACCEL RESPONSE BASE, MAGNITUDE YBTITLE= ACCEL RESPONSE AT BASE, PHASE XYPLOT ACCEL RESPONSE / 9999 (T3RM, T3IP) YTTITLE= ACCEL RESPONSE AT TIP CENTER, MAGNITUDE YBTITLE= ACCEL RESPONSE AT TIP CENTER, PHASE


WS10A-10

Step 1. Review the Input File for MSC.Nastran Users (cont.) XYPLOT ACCEL RESPONSE / 33 (T3RM, T3IP) YTTITLE= ACCEL RESPONSE AT OPPOSITE CORNER, MAGNITUDE YBTITLE= ACCEL RESPONSE AT OPPOSITE CORNER, PHASE XYPLOT ACCEL RESPONSE / 55 (T3RM, T3IP) $ $ PLOT OUTPUT IS ONLY MEANS OF VIEWING PSD DATA $ XGRID= YES YGRID= YES XLOG= YES YLOG= YES YTITLE= ACCEL P S D AT LOADED CORNER XYPLOT ACCEL PSDF / 9999(T3) YTITLE= ACCEL P S D AT TIP CENTER XYPLOT ACCEL PSDF / 33(T3) YTITLE= ACCEL P S D AT OPPOSITE CORNER XYPLOT ACCEL PSDF / 55(T3) $ BEGIN BULK PARAM,COUPMASS,1 PARAM,WTMASS,0.00259 $ INCLUDE ’plate.bdf’ $ GRID, 9999, , 0., 0., 0. $ RBE2, 101, 9999, 12345, 1, 12, 23, 34, 45 $ SPC1, 101, 12456, 9999 $ CONM2, 6000, 9999, , 1.0E8 $ $ EIGENVALUE EXTRACTION PARAMETERS $


EIGRL, 100 , , 2000. $ $ SPECIFY MODAL DAMPING $ TABDMP1, 100, CRIT, +, 0., .03, 10., .03, ENDT $ $ POINT LOADING AT TIP CENTER $ RLOAD2, 100, 600, , , 310 $ TABLED1, 310, +, 10., 1., 1000., 1., ENDT $ DAREA, 600, 9999, 3, 1.E8 $ $ SPECIFY FREQUENCY STEPS $ FREQ,100,30. FREQ1,100,20.,20.,50 FREQ4,100,20.,1000.,.03,5 $ $ SPECIFY SPECTRAL DENSITY $ RANDPS, 100, 1, 1, 1., 0., 111 $ TABRND1, 111,LOG,LOG +, 20., 0.1, 30., 1., 100., 1., 500., .1, +, 1000., .1, ENDT $ ENDDATA

WS10A-11


Windows Users:


Double click on MSC.Nastran icon. Select prob10A.bdf or prob10A.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


WS10A-12


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob10A.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob10A scr=yes. Monitor the run using the UNIX ps command.


WS10A-13


When the run is completed, use plotps utility to create a postscript file, prob10A.ps, from the binary plot file prob10A.plt.

Edit the prob10A.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.

Compare the plot made from the exercise with the plots on the following pages.


WS10A-14

Step 4. View the Plots


WS10A-15

Step 4. View the Plots (cont.)


WS10A-16



WS10A-17



WS10A-18



WS10A-19



WS10A-20

WORKSHOP 10B RANDOM ANALYSIS USING MSC.RANDOM

NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

WS10B-1


WS10B-2

RANDOM RESPONSE

Problem Description

This workshop carries out a Random Response Analysis of the flat plate used through the cases, subject to the PSD acceleration input at the base. The first step is to carry out a Frequency Response analysis based on a unit acceleration applied vertically at the fixed end. The large mass method is used to carry out thin analysis. The second step is to carry out the random response analysis using MSC.Random. This step post-processes the frequency response and model result of the first step.


WS10B-3

RANDOM RESPONSE

Suggested Exercise Steps 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Import the plate model. Create a non-spatial field for the load. Create a frequency dependent load case. Create a point element where the large mass will be applied. Create a RBE2 to connect the point element to the plate. Assign a 1e8 pound mass to the point element. Create the time dependent force. Modify the original constraint from the imported database. Submit the model to MSC.Nastran for analysis. Create a Non Spatial field for the Random Analysis. Open MSC.Random to prepare for Random Analysis. Create XY Plots of the PSD Response.


WS10B-4

CREATE NEW DATABASE

a

d Create a new database called ws9.db. a. File / New. b. Enter ws10B as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


e b

c

f g

WS10B-5

Step 1. File / Import h

a Create the model by importing an existing MSC.Nastran file, plate.bdf. a. Analysis: Read Input File/Model Data. b. Enter prob10B for Job Name. c. Click on Select Input File. d. Select plate.bdf. e. Click OK. f. Click Apply. g. Click OK. h. Click on the Show Labels icon.

d

e

b

c f NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

g WS10B-6

Step 2. Field: Create / Non Spatial / Tabular Input

a

Create a Non Spatial field for the load definition. a. Field: Create / Non Spatial / Tabular Input. b. Enter field for the Field Name. c. Select Frequency (f) as the Active Independent Variable. d. Click Input Data. e. Enter the data shown in the table. f. Click OK. g. Click Apply.

e b

c

f

d

g NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

WS10B-7

Step 3. Load Cases: Create

a Create a Frequency Dependent load case. a. Load Cases: Create b. Enter random for the Load Case Name. c. Select Time Dependent as the Load Case Type. d. Click Assign/Prioritize Loads/ BCs. e. Click on the Displ_constraint in the Select Individual Loads/BCS field. f. Click OK. g. Click Apply.

e

b c

d

f NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

g WS10B-8

Step 4. Elements: Create / Node / Edit

Create a Point Element where the large mass will be applied. a. Elements: Create / Node / Edit. b. Change the Node ID List to 9999. c. Uncheck Associate with Geometry and Auto Execute. d. Enter [-0.5 1 0] for the Node Location. e. Click Apply. f. Click on Node Size button. g. Create / Element / Edit. h. Change the Shape and Topology to Point. i. Select the node created in previous step as Node 1. Note: You do not need to press Apply if Auto Execute is checked.


g f

a

b

h

c i

d e

WS10B-9

Step 5. Elements: Create / MPC / RBE2

Create a RBE2 to connect the Point element to the plate. a. Elements: Create / MPC / RBE2. b. Click Define Terms. c. Choose all the DOFs except for RZ as the DOF for the Dependent Nodes. d. Uncheck Auto Execute and Select the 5 nodes on the left edge of the plate. e. Click Apply. f. Select the created earlier as the Independent Node. g. Click Apply. h. Click Cancel. i. Click Apply.

a

b i

d f c e g


h

WS10B-10

Step 6. Properties: Create / 0D / Mass

Assign a 1e8 pound mass to the Point Element. a. Properties: Create / 0D / Mass. b. Enter mass as the Property Set Name. c. Change the option to Lumped. d. Click on Input Properties. e. Enter 1e8 for the Mass. f. Click OK. g. Click in the Select Members box. h. Change the Entities selection option to Point Element and select the point element created earlier. i. Click Add. j. Click Apply.

a e

h b c d g i f j


WS10B-11

Step 7. Loads/BCs: Create / Force / Nodal

Create the time dependent Force. a. Loads/BCs: Create / Force / Nodal. b. Enter force for the New Set Name. c. Click on the Input Data button. d. Enter <,,1e8> for Force, and select field for the Time/Freq. Dependent Field. e. Click OK. f. Click on Select Application Region. g. Change the Geometry Filter to FEM. h. Select Node 9999. i. Click Add, and click OK. j. Click Apply.

a d g

h i b e

c i

f j


WS10B-12

Step 8. Loads/BCs: Modify / Displacement / Nodal

Modify the original constraint from the imported database. a. Loads/BCs: Modify / Displacement / Nodal. b. Click on constraint in the Select Set to Modify box to select it. c. Click on the Modify Data button. d. Modify the Translation to <0,0,> and Rotations to <0,0,0> e. Click OK. f. Click Modify Application Region. g. Highlight all the data in the Application Region and delete them. h. Select Node 9999. i. Click Add and OK. j. Click Apply.

a d

b h i e

g

c f

i j


WS10B-13

Step 9. Analysis: Analyze / Entire Model / Full Run

Submit the model for analysis. a. Analysis: Analyze / Entire Model / Full Run. b. Click on Solution Type. c. Select Frequency Response. d. Change the Formulation to Modal. e. Click on Solution Parameters button. f. Select Coupled for Mass Calculation. g. Enter 0.00259 for Wt-Mass Conversion. h. Click OK. i. Click OK.

a

f c

g

d e

h i NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

WS10B-14

b


Submit the model for analysis (cont.). a. Click on Subcases. b. Select random from the Available Subcases field. c. Click on Subcase Parameters. d. Click on DEFINE FREQUENCIES button.

d b

e. Enter the frequency data shown in the table. f. Click OK.

c e a

f NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

WS10B-15


Submit the model for analysis (cont.). a. Select Crit. Damp. (CRIT). b. Click on DEFINE MODAL DAMPING. c. Enter the damping information shown in the table.

c a

d. Click OK.

b

e. Click OK.

e

d


WS10B-16


Submit the model for analysis (cont.). a. Click on Output Requests. b. Select Accelerations in the Select Result Type box. c. Click OK. d. Click Apply. e. Click Cancel.

b

a

c NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

d WS10B-17

e


Submit the model for analysis (cont.). a. Click on Subcase Select. b. Select random and unselect Default. c. Click OK. d. Click Apply.

b

a

c d NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

WS10B-18

Step 10. Field : Create / Non Spatial / Tabular Input

a

Create a Non Spatial field for the Random Analysis. a. Field: Create / Non Spatial / Tabular Input. b. Enter Random for the Field Name. c. Select Frequency (f) as the Active Independent Variable. d. Click Input Data. e. Enter the data shown in the table. f. Click OK. g. Click Apply.

e b

c

f

d

g NAS102, Workshop 10B, January 2004 Copyright© 2004 MSC.Software Corporation

WS10B-19

Step 11. Utilities / Applications / MSC.Random

Open MSC.Random to prepare for Random Analysis. a. Utilities / Applications / MSC.Random. b. Select RMS ANALYSIS.

b

a


WS10B-20

Step 11. Utilities / Applications / MSC.Random (Cont.) Setup the model for Random analysis. a. Action: RMS Analysis. Click on Select XDB File. b. Select ws10B.xdb, the results from the previous Frequency Response analysis. c. Click Apply. d. Select Random Input. e. Change the Random Input Method to Single Case. f. Click on the Excited Set field and select 1:RANDOM from the Available Subcases box. g. Click on the Input Field and select Random from the PSD Input fields box. h. Click Close. i. Click Apply.

a

b

a d c

e f

g

i h


WS10B-21

Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response. a. Change Action to XY Plots. b. Select Node 9999. c. Change the Res. Type to Accel. d. Change Component to DOF 3. e. Change the Plot Type to PSDF. f. Click Apply.

a

b c d e

f


WS10B-22

Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a. Select the node at the tip center. b. Click Apply.

a

b


WS10B-23

Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a. Select the node at the tip corner. b. Click Apply.

a

b


WS10B-24

Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a. Change the Plot Type to CRMS. b. Click Apply.

a

b


WS10B-25

Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a. Select the node at the tip center. b. Click Apply.

a

b


WS10B-26

Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a. Select Node 9999. b. Click Apply.

a

b


WS10B-27


WS10B-28

WORKSHOP 11 RANDOM ANALYSIS


WS11-1


WS11-2

Workshop 11 – Random Analysis

Objectives

Define a frequency-varying excitation. Produce a MSC.Nastran input file from a dynamic math model created in Workshop 1. Submit the input file for analysis in MSC.Nastran. Compute nodal displacements for desired frequency domain.


WS11-3


Model Description

Using the modal method, determine the displacement response spectrum of the tip center point due to the input spectrum of the pressure and point loads listed below. Solve using the complex matrix representation [Sab] for the cross spectrum.

Table 11.1 1 psi over the total surface

Table 11.2

50.00

Figure 11.1 - Loads and Boundary Conditions NAS102, Workshop 11, January 2004 Copyright© 2004 MSC.Software Corporation

WS11-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1.

Reference a previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Specify modal damping as a tabular function of natural frequency (TABDMP1). 3. Define the frequency-varying pressure loading (PLOAD2, LSEQ and RLOAD2). 4. Define the frequency-varying tip load (DAREA and RLOAD2). 5. Define a set of frequencies to be used in the solution (FREQ1). 6. Specify spectral density (RANDPS and TABRND1). 7. Prepare the model for random analysis (SOL 111). 8. Request displacement response at loaded corner, tip center, and opposite corner. 9. Generate an input file and submit it to the MSC.Nastran solver for random analysis. 10. Review the results, specifically the nodal displacements.


WS11-5

Workshop 11 – Random Analysis ID SEMINAR, PROB11 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS11-6

Workshop 11 – Random Analysis 1

2

3


4

5

6

WS11-7

7

8

9

10

Workshop 11 – Random Analysis 1

2

3

4

5

6

ENDDATA


WS11-8

7

8

9

10


MSC.Nastran users who created the input file using a text editor, the input file (prob9b.dat) should be similar to the file below:

ID SEMINAR, PROB11 SOL 111 TIME 30 CEND TITLE= FREQUENCY RESPONSE WITH PRESSURE AND POINT LOADS SUBTITLE= USING THE MODAL METHOD WITH LANCZOS ECHO= UNSORTED SPC= 1 SET 111= 11, 33, 55 DISPLACEMENT(SORT2, PHASE)= 111 METHOD= 100 FREQUENCY= 100 SDAMPING= 100 RANDOM= 100 SUBCASE 1 LABEL= PRESSURE LOAD DLOAD= 100 LOADSET= 100 SUBCASE 2 LABEL CORNER LOAD DLOAD= 200 LOADSET= 100 $ OUTPUT (XYPLOT) $ XTGRID= YES YTGRID= YES XBGRID= YES YBGRID= YES YTLOG= YES YBLOG= NO XTITLE= FREQUENCY (HZ) YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASE XYPLOT DISP RESPONSE / 11 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDE


YBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASE XYPLOT DISP RESPONSE / 33 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASE XYPLOT DISP RESPONSE / 55 (T3RM, T3IP) $ $ PLOT OUTPUT IS ONLY MEANS OF VIEWING PSD DATA $ XGRID= YES YGRID= YES XLOG= YES YLOG= YES YTITLE= DISP P S D AT LOADED CORNER XYPLOT DISP PSDF / 11(T3) YTITLE= DISP P S D AT TIP CENTER XYPLOT DISP PSDF / 33(T3) YTITLE= DISP P S D AT OPPOSITE CORNER XYPLOT DISP PSDF / 55(T3) $ BEGIN BULK $ PARAM,COUPMASS,1 $ PARAM,WTMASS,0.00259 $ $ MODEL DESCRIBED IN NORMAL MODES EXAMPLE $ INCLUDE ’plate.bdf’ $ $ EIGENVALUE EXTRACTION PARAMETERS $ EIGRL, 100, 10., 2000. $ $ SPECIFY MODAL DAMPING $

WS11-9

Step 1: Generate and Review Input File (cont.) TABDMP1, 100, CRIT, +, 0., .03, 10., .03, ENDT $ $ FIRST LOADING $ RLOAD2, 100, 300, , , 310 $ TABLED1, 310, +, 10., 1., 1000., 1., ENDT $ $ UNIT PRESSURE LOAD TO PLATE $ LSEQ, 100, 300, 400 $ PLOAD2, 400, 1., 1, THRU, 40 $ $ SECOND LOADING $ RLOAD2, 200, 600, , , 310 $ $ POINT LOAD AT TIP CENTER $ DAREA, 600, 11, 3, 1. $ $ SPECIFY FREQUENCY STEPS $ FREQ1, 100, 20., 20., 49 $ $ SPECIFY SPECTRAL DENSITY $ RANDPS, 100, 1, 1, 1., 0., 100 RANDPS, 100, 2, 2, 1., 0., 200 RANDPS, 100, 1, 2, 1., 0., 300 RANDPS, 100, 1, 2, 0., 1.0, 400 $ TABRND1, 100, +, 20., 0.1, 30., 1., 100., 1., 500., .1, +, 1000., .1, ENDT $ TABRND1, 200, +, 20., 0.5, 30., 2.5, 500., 2.5, 1000., 0.,


+, ENDT $ TABRND1, 300, +, 20., -.099619, 100., -.498097, 500., .070711, 1000., 0., +, ENDT $ TABRND1, 400, +, 20., .0078158, 100., .0435791, 500., -.70711, 1000., 0., +, ENDT $ ENDDATA

WS11-10


Windows Users:




WS11-11


Unix Users:




WS11-12


When the run is completed, use the plotps utility to create a postscript file, prob11.ps, from the binary plot file prob11.plt. Compare the results with the plots on the following pages.


WS11-13



WS11-14



WS11-15



WS11-16



WS11-17



WS11-18



WS11-19



WS11-20



WS11-21



WS11-22

WORKSHOP 12 COMPLEX MODES OF A PILE DRIVER


WS12-1


WS12-2

Workshop 12 – Complex Modes of a Pile Driver

Objectives

Define complex eigenvalue extraction parameters. Submit the file for analysis in MSC.Nastran. Compute complex modes.


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Problem Description

The model is idealized as shown below in Figure 12.1. (Note that both a spring element and a damper element will be created connecting Grid 2 and Grid 3.)

M1

3.0 lb-sec2/in

M2

1.5 lb-sec2/in

K1

50,000 lb/in

K2

12,5000 lb/in

C2

30 lb-sec/in

Figure 12.1 – Model Description


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MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Generate a finite element representation of the pile driver using GRID, CONM2, CELAS, and CVISC elements. 2. Define material (MAT1), and element (PELAS) and (PVISC) properties. 3. Apply x-direction boundary constraint (SPC1). 4. Specify complex eigenvalue extraction parameters (CMETHOD) and (EIGC). 5. Prepare the model for complex eigenvalue analysis (SOL107). 6. Go to Step 6 for MSC.Patran users.


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Workshop 12 – Complex Modes of a Pile Driver ID SEMINAR, PROB12 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 12 – Complex Modes of a Pile Driver 1

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Workshop 12 – Complex Modes of a Pile Driver 1

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MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9.

Create a new database. Create the model by the edit method. Create element properties. Create the constraint at the ground. Create the input file. Submit the input file for MSC.Nastran analysis. Review the .F06 file. Attach the XDB file. View the results.


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a

Create a new database named prob12.db. a. File / New. b. Enter prob12 as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


d

e f c

b

g

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Step 2. Create the Model by Edit Method f

Create the model by the edit method in the Finite Elements menu. a. Elements: Create/Node/Edit. b. Uncheck Associate with Geometry. c. Uncheck Auto Execute. d. Enter [0 0 0] for Node Location List. e. Click Apply. f. Click the Show Labels icon. g. Click the Node Size icon.

a

b c d e


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g

Step 2. Create the Model by Edit Method (cont.)

Similarly, create Nodes 2 and 3. a. Enter [1 0 0] under Node Location List. b. Click Apply. c. Enter [2 0 0] under Node Location List. d. Click Apply.

a

c b


d

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a Create the Bar Element for Node 1 and Node 2. a. Elements: Create/Element/Edit. b. Select Bar for Shape. c. Node 1 = Node 1. d. Node 2 = Node 2. e. Node 1 = Node 2. f. Node 2 = Node 3.


b

c

e

d

f

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Create the 2 mass elements at Node 1 and Node 2. a. Elements: Create/Element/Edit. b. Select Point for Shape. c. Unclick Auto Execute. d. Check that 3 is listed in the Element ID List. e. Node 1 = Node 1. f. Click Apply. g. Check that 4 is listed in the Element ID List. h. Node 1 = Node 2. i. Click Apply.

a

g

d b

c

h

e f


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i


a

Create the damper elements connecting Node 2 and 3. a. Elements: Create/Element/Edit. b. Select Bar for Shape. c. Uncheck Auto Execute d. Node 1 = Node 2. e. Node 2 = Node 3. f. Click Apply.

g b

c d e f


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Step 3. Create Element Properties

a Create the spring. a. Properties: Create/1D/Spring. b. Enter spring as Property Set Name. c. Click Input Properties… d. Enter 50000 for Spring Constant. e. Select UX for Dof at Node 1. f. Select UX for Dof at Node 2. g. Click OK. h. Click in the Select Members box. i. Click the Beam Element icon. j. Select Element 1. k. Click Add. l. Click Apply.

d

e f i b c j


h k

g l

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Step 3. Create Element Properties (cont.)

Similarly, create the spring constant of 12,500 for the 2nd spring element. a. Properties: Create/1D/Spring. b. Enter spring2 as Property Set Name. c. Click on Input Properties… d. Enter 12500 for Spring Constant. e. Select UX for Dof at Node 1. f. Select UX for Dof at Node 2. g. Click OK. h. Click in the Application Region box. i. Click the Beam Element icon. j. Select Element 2. k. Click Add. l. Click Apply.

a d

e f i

b c j

h k


g l WS12-17


Create the damper. a. Properties: Create/1D/Damper. b. Enter damper as Property Set Name. c. Select Viscous under Options… d. Click on Input Properties… e. Enter 30 as Ext. Viscous Coeff. f. Click OK. g. Click in the Application Region box. h. Make sure the Beam Element icon is selected. i. Select Element 5. j. Click Add. k. Click Apply.

a e

b h

c d i

g j

f k NAS102, Workshop 12, January 2004 Copyright© 2004 MSC.Software Corporation

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Create the mass properties of the mass elements. a. Properties: Create/0D/Mass. b. Enter mass1 as Property Set Name. c. Select Lumped under Options. d. Click on Input Properties… e. Enter 3 for Mass. f. Click OK. g. Click in the Application Region box. h. Click the Point Element icon. i. Select Element 3. j. Click Add. k. Click Apply.

a e

b h c d i

g

j f k


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Similarly, create the mass property of the 2nd mass element. a. Properties: Create/0D/Mass. b. Enter mass2 as Property Set Name. c. Select Lumped under Options. d. Click on Input Properties… e. Enter 1.5 for Mass. f. Click OK. g. Click in the Application Region box. h. Make sure the Point Element icon is selected. i. Select Element 4. j. Click Add. k. Click Apply.

a

e

b h

c d i j

g

f

k NAS102, Workshop 12, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 4. Create the Constraint

Create the constraint at the ground. a. Loads/BC’s: Create/Displacement/ Nodal. b. Enter constraint for New Set Name. c. Click on Input Data… d. Enter <0, , > for Translations . e. Click OK. f. Click on Select Application Region… g. Select FEM as Geometry Filter. h. Select Node 3. i. Click Add. j. Click OK. k. Click Apply.

a g d

h i

b

j e

c f k


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a Create the Analysis Deck. a. Analysis: Analyze/Entire Model/Analysis Deck. b. Enter prob12 for the Job Name. c. Click on Solution Type… d. Select COMPLEX EIGENVALUE. e. Select Direct for Formulation. f. Click on Solution Parameters…

d

b e f c


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a. Click on Complex Eigenvalue… b. Enter 4 as the Number of Desired Roots. c. Click OK. d. Click OK. e. Click OK. f. Click Apply.

b

a

d


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An MSC.Nastran input file called prob12.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to Step 7.


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For MSC.Nastran users who created the input file using a text editor, the input file (prob12.dat) should be similar to the file below: ID SEMINAR, PROB12 CONM2, 202, 2, , 1.5 SOL 107 SPC, 100, 3, 1 TIME 5 $ CEND $ DEFINE DAMPER OF 30 BETWEEN GRIDS 2 AND 3 TITLE= TWO-DOF MODEL (IMAC 8, PG 891) $ SUBTITLE= COMPLEX MODES CVISC, 101, 1, 2, 3 DISPLACEMENT= ALL $ DEFAULT= REAL, IMAGINARY PVISC, 1, 30. SPC= 100 $ CMETHOD= 99 ENDDATA $ BEGIN BULK $ $ COMPLEX EIGENVALUE EXTRACTION PARAMETERS $ EIGC, 99, HESS, , , , , 4 $ $ DEFINE GRIDS, MASSES, AND STIFFNESSES $ GRID 1 = EXCITER (X=2, MASS=3) 50K STIFFNESS BETWEEN GRIDS 1 AND 2 $ GRID 2 = PILE (X=1, MASS=3) 12.5K STIFFNESS BETWEEN GRIDS 2 AND 3 $ GRID 3 = BASE (X=0, FIX BASE) $ GRID, 1, , 2., 0., 0. GRID, 2, , 1., 0., 0. GRID, 3, , 0., 0., 0. GRDSET, , , , , , , 23456 CELAS2, 1, 50000., 1, 1, 2, 1 CELAS2, 2, 12500., 2, 1, 3, 1 CONM2, 201, 1, , 3.0


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Windows Users:




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Unix Users:




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Edit the prob12.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.

MSC.Patran Users should proceed to Step 10.


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While still editing prob12.f06, search for the word: E I G E N V A L U E (spaces are necessary).



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Step 9. Compare the Results (cont.)

MSC.Nastran MSC.NastranUsers Usershave havefinished finishedthis thisworkshop. workshop. MSC.Patran MSC.PatranUsers Users should shouldproceed proceedto tothe thenext nextstep. step. NAS102, Workshop 12, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 10. Attach the XDB File

a

a

Proceed with the Reverse Translation process, that is importing the prob12.xdb results file into MSC.Patran. To do this, return to the Analysis form and proceed as follows: a. Analysis: Access Results/Attach XDB/Result Entities. b. Click on Select Results File… c. Select prob12.xdb. d. Click OK. e. Click Apply.

c

d

b


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Step 11. View the Results

a

In the Results menu: a. Results: Create/Deformation. b. Select Default, Mode 1: freq. = 7.9315 under Select Results Cases. c. Select Eigenvectors, Translational under Select Deformation Result. d. Click on the Plot Options icon. e. Set the Complex No. as: Imaginary. f. Click Apply.

d b

e

c


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Step 11. View the Results (cont.)


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WORKSHOP 13 NOLINS IN LINEAR TRANSIENT


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Workshop 13- Nolins in Linear Transient

Objectives

Represent non-structural variables using non-structural DOFs. Define dynamic functions with transfer functions. Create a nonlinear transient force. Prepare a MSC.Nastran input file for transient analysis. View results.


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Model Description

Figure 13.1 Car Traveling Over a Speed Bump


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Figure 13.2 Force vs Relative Velocity


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MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Generate a finite element representation of the model using (GRID), (CBAR), and (CELAS2) elements. Define material (MAT1) and element (PBAR) properties. Constraints to eliminate rigid-body modes (SPC1). Define non-structural variables (CONM2). Specify scalar damper property and connection (CDAMP2). Define extra points (EPOINT). Define dynamic transfer functions (TF). Add non-linear portion of the spring (NOLIN1). Add non-linear portion of the damper (NOLIN4). Define the time-varying load (DAREA & TLOAD2). Define the time delay (DELAY). Specify integration time step. Prepare the model for direct transient analysis. Request response in terms of nodal displacement and non-linear load output. Generate an input file and submit it to the MSC.Nastran solver for direct transient analysis. Review the results, specifically the xy ploy of nodal displacements and non-linear load.


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Workshop 13- Nolins in Linear Transient ID SEMINAR, PROB13 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 13- Nolins in Linear Transient 1

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Workshop 13- Nolins in Linear Transient 1

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ENDDATA


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Workshop 13 – Nolins in Linear Transient

MSC.Patran Users 1. 2. 3. 4. 5. 6.

Create and review the MSC.Nastran input file. Submit the input file to MSC.Nastran for analysis. Review the .f06 file. Create a database. Read the .op2 output file. View results.


WS13-10

Step 1: Create and Review Input File

MSC.Nastran users who created the input file using a text editor, the input file (prob13.dat) should be similar to the file below:

ASSIGN OUTPUT2 = ’prob13.op2’, UNIT=12 ID NAS102, WORKSHOP13 SOL 109 TIME 100 CEND TITLE= SIMPLE CAR MODEL WITH NOLINEAR SUBTITLE= SPRINGS AND DAMPERS RUNNING OVER A BUMP LABEL= SOL 109, CONSTANT DELTA TIME SEALL= ALL SPC= 100 TFL= 100 NONLINEAR = 100 DLOAD = 100 TSTEP = 100 DISPLACEMENT(PLOT)= ALL NLLOAD(PLOT)= ALL $ OUTPUT(XYPLOT) CSCALE=1.3 XAXIS= YES YAXIS= YES XGRID LINES= YES YGRID LINES= YES XTITLE= TIME (SEC) YTITLE= VERTICAL DISPLACEMENT OF POINT 1 XYPLOT DISP/1(T2) YTITLE= VERTICAL DISPLACEMENT OF POINT 2 XYPLOT DISP/2(T2) YTITLE= VERTICAL DISPLACEMENT OF POINT 3 XYPLOT DISP/3(T2) YTITLE= VERTICAL DISPLACEMENT OF POINT 4 XYPLOT DISP/4(T2) YTITLE= VERTICAL DISPLACEMENT OF POINT 5 XYPLOT DISP/5(T2) YTITLE= NONLINEAR FORCES AT POINT 1 XYPLOT NONLINEAR/1(T2)


YTITLE= NONLINEAR FORCES AT POINT 2 XYPLOT NONLINEAR/2(T2) $ BEGIN BULK PARAM,POST,-1 PARAM,PATVER,3.0 $ $ CARRIAGE POINTS $ GRID, 1, , 0., 0., 0. GRID, 2, , 120., 0., 0. GRID, 5, , 60., 0., 0. $ $ WHEEL POINTS $ GRID, 3, , 0., -10., 0. GRID, 4, , 120., -10., 0. $ $ CAR CARRIAGE $ CBAR, 5, 11, 1, 5, 0., 1., 0. CBAR, 6, 11, 5, 2, 0., 1., 0. PBAR, 11, 12, 10., 10., 10. MAT1, 12, 3.0E+7, , .33 $ $ CONSTRAINTS TO ELIMINATE RIGID-BODY MODES $ SPC1, 100, 1345, 1, 2, 5 SPC1, 100, 13456, 3, 4 $ $ SYSTEM WILL HAVE A NATURAL FREQUENCY OF 1 HZ $ WITH CRITICAL DAMPING OF 1 PERCENT $ CONM2, 10, 1, ,2.5 CONM2, 15, 2, ,2.5 CONM2, 20, 5, ,5.

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Step 1: Create and Review Input File (cont.) $ CELAS2, 30, 197.4, 1, 2, 3, 2 CELAS2, 40, 197.4, 2, 2, 4, 2 $ CDAMP2, 50, 1.88, 1, 2, 3, 2 CDAMP2, 60, 1.88, 2, 2, 4, 2 $ $ DEFINE EXTRA POINTS TO HOLD DIFFERENCES $ BETWEEN WHEELS AND CARRIAGE $ EPOINT, 101, 102 $ $ USE TRANSFER FUNCTIONS TO TRACK DIFFERENCES $ 101= V1 - V3 $ 102= V2 - V4 $ TF, 100, 101, 0, 1., 0., 0., , 1, 2, -1., 0., 0., , 3, 2, 1., 0., 0. $ TF, 100, 102, 0, 1., 0., 0., , 2, 2, -1., 0., 0., , 4, 2, 1., 0., 0. $ $ ADD NONLINEAR PORTION OF SPRINGS $ NOLIN1, 100, 1, 2, 197.4, 101, 0, 111 NOLIN1, 100, 2, 2, 197.4, 102, 0, 111 TABLED2, 111, -2.0, , -1., 1., 0., 0., 1., 0.,ENDT $ $ ADD NONLINEAR PORTION OF DAMPERS $ NOLIN4, 100, 1, 2, -0.3, 101, 10, 2. NOLIN4, 100, 2, 2, -0.3, 102, 10, 2. $ $ USE LAGRANGE MULTIPLIERS TO IMPOSE WHEEL DISPLACEMENT $ 103= V3 $ 104= V4 $ EPOINT, 103, 104


$ TF, 100, 103, 0, 0., 0., 0., , 3, 2, 1., 0., 0. TF, 100, 3, 2, 0., 0., 0., , 103, 0, 1., 0., 0. $ TF, 100, 104, 0, 0., 0., 0., , 4, 2, 1., 0., 0. TF, 100, 4, 2, 0., 0., 0., , 104, 0, 1., 0., 0. $ $ MOVE WHEELS OVER BUMP $ TLOAD2, 100, 222, 333, 0, 0., 0.5, 1., -90. DAREA, 222, 103, 0, 4. DAREA, 222, 104, 0, 4. DELAY, 333, 104, 0, 1.2 $ $ INTEGRATION INFORMATION TSTEP, 100, 200, .05, 1 $ ENDDATA

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Windows Users:




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Unix Users:




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Step 3: Review the .f06 File

When the run is completed, use the plotps utility to create a postscript file, prob13.ps, from the binary plot file plot13.plt. Monitor the run using the UNIX ps command.


While still editing prob13.f06, search for the word X Y – O U T P U T S U M M A R Y (spaces are necessary).


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Step 3: Review the .f06 File (cont.)



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a



e f c

b

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g

Step 5. Read Output File

Read the .op2 output file. a. Analysis: Access Results / Read Output2 / Both. b. Click on Select Results File. c. Select prob13.xdb. d. Click OK. e. Click Apply.

a

c

d

b e NAS102, Workshop 13, January 2004 Copyright© 2004 MSC.Software Corporation

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Create a X-Y graph of displacement results. a. Results: Create / Graph / Y vs X. b. Under Select Result case(s), click on SPRINGS AND DAMPERS RUNNING OVER A BUMP, 0 of 201 subcases. c. Select All as the Filter Method. d. Click Filter. e. Click Apply. f. Click Close.

a

b c

d

f

e


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Create a X-Y graph of displacement results (cont.). a. Select Nonlinear Applied Loads, Translational for the Select Y Result field. b. Select Magnitude as the Quantity. c. Click on the Target Entities icon. d. Change the Target Entity Selection to Nodes. e. Select the top left node (Node 1). f. Click Apply.

c

d e

a

b f


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Nonlinear Forces at Point 1


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Create a X-Y graph of displacement results (cont.). a. Under Select Nodes, select the top right node (Node 2). b. Click Apply.

Nonlinear Forces at Point 2

a

b


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Create a X-Y graph of displacement results (cont.). a. Under Select Nodes, select the top left node (Node 1). b. Click Select Results. c. Under Select Y Result, select Displacements, Translational. d. Change the Quantity to Y Component. e. Click Apply.

b

a

c

d


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Vertical Displacement at Point 1


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Create a X-Y graph of displacement results (cont.). a. Click Target Entities. b. Under Select Nodes, select the top right node (Node 2). c. Click Apply.

a

b

To plot the displacements of nodes 3, 4 and 5, simply select each node and click apply.

c


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WORKSHOP 14a MODAL ANALYSIS OF A BEAM


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Workshop 14a – Modal Analysis of a Beam

Objectives

Perform normal modes analysis of a cantilever beam. Submit the file for analysis in MSC.Nastran. Find the first three natural frequencies and mode shapes of the beam.


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Problem Description

The goal of this example is to find the first 3 modes of a beam pinned at both ends.

Figure 14a.1 below is a finite element representation of the beam. One end is constrained in all translation and the other is free to move in the X. Both ends are held in the X-rotation.

Figure 14a.1 – Grid Coordinates and Element Connectivites


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Figure 14a.2 – Beam Cross Section Length

100 in

Height

2 in

Width

1 in

Thickness

0.100 in

Area

0.38 in2

I1

0.229in4

I2

0.017in4

Table 14a.1


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Hand Calculations:

I of the strong axis is used since translational Z DOF has been constrained by the permanent constraint.


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From Theory:


Mode

Kn

fn

1

9.87

23.85 Hz

2

39.5

95.46

3

88.8

214.59 Hz

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MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Explicitly generate a finite element representation of the beam structure (I.e. the (GRID) and element connectivities (CBAR) should be defined manually). 2. Define material (MAT1) and element (PBARL) properties. 3. Apply the fixed boundary constraints (SPC1). 4. Prepare the model for a normal modes analysis (SOL 103 and PARAMS). 5. Generate an input file for MSC.Nastran. 6. Go to Step 8 for MSC.Patran users.


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Workshop 14a – Modal Analysis of a Beam ID SEMINAR, PROB14A _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 14a – Modal Analysis of a Beam 1

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MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Create a new database. Create the geometry. Create the finite element model and mesh the surface. Create the nodal displacements. Create a set of material properties. Define the bar properties. Generate the input file for analysis. Submit the input file to MSC.Nastran for analysis. Attach the XDB file. View the results.


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a

Create a new database named prob14a.db. a. File / New. b. Enter prob14a as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


d

e f b

c

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g

Step 2. Create the Geometry f

Create a curve. a. Geometry: Create/Curve/XYZ. b. Uncheck Auto Execute. c. Enter <100, 0, 0> in the Vector Coordinates List. d. Enter [0, 0, 0] in the Origin Coordinates List. e. Click Apply. f. Click on the Show Labels icon.

a

e

c b d e


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Step 3. Create the Finite Element Model

a Create the finite element model and mesh the surface. a. Elements: Create/Mesh/Curve. b. Uncheck Automatic Calculation. c. Set the Global Edge Length to 10. d. Select Curve 1 for the Curve List. e. Click Apply.

d

d b c


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Step 4. Create the Nodal Displacements

a In the Loads/BCs menu, a. Create/Displacement/Nodal. b. Enter disp1 as the New Set Name. c. Click on Input Data… d. Enter <0 0 0> for Translations . e. Enter <0, , > for Rotations . f. Click OK. g. Click on Select Application Region… h. Select Geometry as Filter. i. Select Point 1. j. Click Add. k. Click OK. l. Click Apply.

h d e

i j

b

f k

c g l NAS102, Workshop 14a, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 4. Create the Nodal Displacements (cont.)

a. Enter disp2 for New Set Name. b. Click on Input Data… c. Enter < ,0, 0> for Translations . d. Enter <0, , > for Rotations . e. Click OK. f. Click on Select Application Region… g. Select Point 2 under Select Geometric Entities. h. Click Add. i. Click OK. j. Click Apply.

c d

g h

a

i e

b f j NAS102, Workshop 14a, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 4. Create the Nodal Displacements (cont.)

a. Enter permanent_constraint for New Set Name. b. Click on Input Data… c. Enter < , , 0> for Translations . d. Enter <0, 0, > for Rotations . e. Click OK. f. Click on Select Application Region… g. Select Curve 1 for Select Geometric Entities. h. Click Add. i. Click OK. j. Click Apply.

c d

g h

a

e

b f j NAS102, Workshop 14a, January 2004 Copyright© 2004 MSC.Software Corporation

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i


a Create a set of material properties fro the bar. a. Materials: Create/Isotropic/Manual Input. b. Enter alum as the Material Name. c. Click on Input Properties… d. Enter 10.0E6 for Elastic Modulus. e. Enter 0.3 for the Poisson Ratio. f. Enter 0.101 for the Density. g. Click OK. h. Click Apply.

a d e f

b

c h NAS102, Workshop 14a, January 2004 Copyright© 2004 MSC.Software Corporation

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g

Step 6. Define the Bar Properties

a a. Properties: Create/1D/Beam. b. Enter bar as Property Set Name. c. Click Input Properties… d. Click on the Mat Prop Name icon. e. Select alum under Select Existing Material. f. Click on the Create Sections Beam Library icon.

e

d

b

c f


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Step 6. Define the Bar Properties (cont.)

a. Enter beam as New Section Name. b. Enter the following: H=2 W1 = 1 W2 = 1 t = 0.1 t1 = 0.1 t2 = 0.1 c. Click OK.

b a


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Step 6. Define the Bar Properties (cont.)

a. Enter Coord 0.2 for Bar Orientation. b. Click OK. c. Select Curve 1 for Select Members. d. Click Add. e. Click Apply.

a

c d b e NAS102, Workshop 14a, January 2004 Copyright© 2004 MSC.Software Corporation

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Create an input file for analysis: a. Analysis: Analyze/Entire Model/Analysis Deck. b. Enter prob14a for Job Name. c. Click on Solution Type… d. Select NORMAL MODES for Solution Type. e. Click on Solution Parameters… f. Uncheck Automatic Constraints. g. Select Coupled for Mass Calculation, None for Data Deck Echo, and enter 0.00259 for Wt.-Mass Conversion. h. Click OK. i. Click OK.

a f d g

g

b

e c i h


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b

a. Click on Subcases… b. Select Default from Available Subcases. c. Click on Subcase Parameters… d. Enter 3 as the Number of Desired Roots. e. Click OK. f. Click Apply. g. Click Cancel. h. Click Apply.

d

c

a e h NAS102, Workshop 14a, January 2004 Copyright© 2004 MSC.Software Corporation

f WS14a-24

g


An MSC.Nastran input file called prob14a.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to Step 9.


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Windows Users:


Double click on MSC.Nastran icon. Select prob14a.bdf or prob14.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


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Unix Users:




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While still editing the prob14a.f06, search for the words: E I G E N (spaces are necessary) What are the first three modes? 1st = _______Hz 2nd = _______Hz 3rd = _______Hz


WS14a-30





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a

a Proceed with the Reverse Translation process, that is importing the prob14a.xdb results file into MSC.Patran. To do this, return to the Analysis form and proceed as follows: a. Analysis: Access Results/Attach XDB/Result Entities. b. Click on Select Results File… c. Select prob14a.xdb. d. Click OK. e. Click Apply.

c

d

b


WS14a-32


a

When the translation is complete, bring up the Results form. a. Create/Deformation. b. Select Default, Mode 1: Freq = 23.816 under Select Result Cases. c. Select Eigenvectors, Translational under Select Deformation Result. d. Click Apply.

b

c

d

d NAS102, Workshop 14a, January 2004 Copyright© 2004 MSC.Software Corporation

WS14a-33


WS14a-34

WORKSHOP 14b NORMAL MODES WITH DIFFERENTIAL STIFFNESS


WS14b-1


WS14b-2

Workshop 14b – Normal Modes With Differential Stiffness

Objectives

Analyze a stiffened beam for normal modes. Produce an MSC.Nastran input file that represents beam and load. Submit for MSC.Nastran analysis. Find normal modes (natural frequencies).


WS14b-3

Workshop 14b – Normal Modes with Differential Stiffness

Problem Description

The goal of this example is to analyze a stiffened model. In this case, the beam from Problem 14a will be analyzed with a 500 lb force applied.

Figure 14b.1 below is a finite element representation of the beam. This is no longer a simple normal modes analysis. Instead we will be using a nonlinear static solution (SOL 106) with (PARAM, NMLOOP, and METHOD and EIGRL).

Below is a finite element representation of the beam. One end is pinned in three translations and one rotation. The other is pinned in two translations and one rotation with a 500 lb force applied.

Figure 14b.1 – Grid Coordinates and Element Connectivites NAS102, Workshop 14b, January 2004 Copyright© 2004 MSC.Software Corporation

WS14b-4


Figure 14b.2 – Beam Cross Section Length

100 in

Height

2 in

Width

1 in

Thickness

0.100 in

Area

0.38 in2

I1

0.229in4

I2

0.017in4

Table 14b.1


WS14b-5


Theoretical Solution:

For Static Load:


WS14b-6


MSC.Nastran Users – Modify an MSC.Nastran input file using a text editor 1. Open database created in Problem 14a in order to modify it, adding a load and reanalyze. 2. Create 500 lb force applied at one end (FORCE). 3. Make sure analysis is set to nonlinear static (SOL 106). 4. Preprare nonlinear analysis to also analyze for normal mode (PARAM, NMLOOP, EIGRL, LGDISP, NLPARAM). 5. Go to Step 4 for MSC.Patran users.


WS14b-7

Workshop 14b – Normal Modes With Differential Stiffness ID SEMINAR, PROB14B _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Workshop 14b – Normal Modes With Differential Stiffness 1

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Workshop 14b – Normal Modes With Differential Stiffness 1

2

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ENDDATA


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10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7.

Open database created in Problem 14a. Create the force. Generate the input file for analysis. Submit the input file to MSC.Nastran for analysis. Review the F06 file. Attach the XDB file. View the results.


WS14b-11

Step 1. Create a Database a

b Open database created in Problem a14a named probl14a.db. a. File/Open. b. Select prob14a.db. c. Click OK.


c

WS14b-12

Step 2. Create the Force a

b Create the nodal force in the Loads/BCs menu. a. Click on the Show Labels icon. b. Create/Force/Nodal. c. Enter pull as New Set Name. d. Click on Input Data… e. Enter <500, , > for Force . f. Click OK. g. Click on Select Application Region… h. Select Point 2 under Select Geometry Entities. i. Click Add. j. Click OK. k. Click Apply.

e

h i

c

d

f

g k


WS14b-13

j


Create an input file for analysis: a. Analysis: Analyze/Entire Model/Analysis Deck. b. Enter prob14b for Job Name. c. Click on Solution Type… d. Select NONLINEAR STATIC for Solution Type. e. Click on Solution Parameters… f. Uncheck Automatic Constraints. g. Select Coupled for Mass Calculation, None for Data Deck Echo, and enter 0.00259 for Wt.-Mass Conversion. h. Click OK. i. Click OK.

a

f

d

g

b

e c

i


WS14b-14

h


c a. Click on Direct Text Input… b. Select Case Control Section. c. Enter METHOD = 10. d. Click on Bulk Data Section. e. Enter PARAM, NMLOOP,5 and EIGRL,10, , , 3. f. Click OK.

b

e

a

d f NAS102, Workshop 14b, January 2004 Copyright© 2004 MSC.Software Corporation

WS14b-15


d b

a. Click on Subcases… b. Select Default from Available Subcases. c. Click on Subcase Parameters… d. Enter 5 as the Number of Load Increments. e. Click OK. f. Click Apply. g. Click Cancel. h. Click Apply.

c

a e h NAS102, Workshop 14b, January 2004 Copyright© 2004 MSC.Software Corporation

f WS14b-16

g


An MSC.Nastran input file called prob14b.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to Step 5.


WS14b-17


For MSC.Nastran users who created the input file using a text editor, the input file (prob14b.dat) should be similar to the file below:


WS14b-18

Step 4. Review Input File for MSC.Nastran Users (cont.)


WS14b-19


Windows Users:


Double click on MSC.Nastran icon. Select prob14b.bdf or prob14b.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


WS14b-20


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob14b.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob14b scr=yes. Monitor the run using the UNIX ps command.


WS14b-21


When the run is completed, edit the prob14b.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.

While still editing the prob14b.f06, search for the words: E I G E N (spaces are necessary) What are the first three natural frequencies? 1st = _______Hz 2nd = _______Hz 3rd = _______Hz


WS14b-22





WS14b-23


a

a

Proceed with the Reverse Translation process, that is attaching the prob14b.xdb results file into MSC.Patran. To do this, return to the Analysis form and proceed as follows: a. Analysis: Access Results / Attach XDB/Result Entities. b. Click Select Results File. c. Select prob14b.xdb. d. Click OK. e. Click Apply.

c

d

b

e NAS102, Workshop 14b, January 2004 Copyright© 2004 MSC.Software Corporation

WS14b-24


a

When the translation is complete, bring up the Results form. a. Create/Deformation. b. Select Default, Mode 1: Freq = 26.325 under Select Result Cases. c. Select Eigenvectors, Translational under Select Deformation Result. d. Click Apply.

b

c

d NAS102, Workshop 14b, January 2004 Copyright© 2004 MSC.Software Corporation

WS14b-25


WS14b-26

WORKSHOP 15 WEIGHT MINIMIZATION OF A THREE BAR TRUSS


WS15-1


WS15-2

Workshop 15 – Weight Minimization of a Three Bar Truss

Objectives

Minimize the weight of the truss. First mode must be between 1500 – 1550 Hz. Submit the file for analysis in MSC.Nastran. Recover the desired objective while satisfying the frequency requirement.


WS15-3


Model Description

You must minimize the weight of the following three bar truss problem. The first mode must be between 1500 – 1550 Hz. The model will have different areas for the inside and outside beams. The structure must remain symmetric.


Table 15.1


WS15-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

12. 13.

Generate the analysis model. The nodes (GRID) and element connectivities (CROD) should be defined manually. Define material (MAT1) and element (PROD) properties. Apply fixed boundary constraints (SPC1) to the upper nodes. Create the appropriate design optimization model. Define the design variables (DESVAR). Relate one design variable to another design variable (DLINK). Define design variable to analysis model parameter relations (DVPREL). Specify design sensitivity response quantities (DRESP1). Define constraints (DCONSTR). Define optimization control parameters (DOPTPRM). Prepare the model for linear static analysis and normal modes analysis using Lanczos Method. z PARAM, WTMASS, 0.00259 Generate an input file and submit it to MSC.Nastran for structural optimization analysis. Review the results, specifically the eigenvalues and the design variable history.


WS15-5

Workshop 15 – Weight Minimization of a Three Bar Truss ID SEMINAR, PROB15 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


WS15-6

Workshop 15 – Weight Minimization of a Three Bar Truss 1

2

3


4

5

6

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Workshop 15 – Weight Minimization of a Three Bar Truss 1

2

3

4

5

6

ENDDATA


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MSC.Nastran MSC.NastranUsers Usersshould shouldgo goto tostep step10 10

MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.

Create a new database. Create elements that make up the truss. Define the material. Create the material properties. Create load/boundary conditions. Create a load case. Create model variables. Create a design study. Create the input file. Review the input file for MSC.Nastran users. Submit the input file to MSC.Nastran for analysis. Review the .F06 file. Read the .op2 output file. View results.


WS15-9


a



e f c

b

WS15-10

g

Step 2. Create Elements a

b

Create the truss geometry. a. Click Show Labels. b. Switch to Front View. c. Elements: Create / Node / Edit. d. Uncheck Associate with Geometry. e. Uncheck Auto Execute. f. Under Node Location List, enter each of the following entries and click Apply: [-10 0 0], [0 0 0], [10 0 0], [0 –10 0].

c

d e f f


WS15-11

Step 2. Create Elements (cont.)

Create the truss geometry (cont.). a. Elements: Create / Element / Edit. b. Change the Shape to Bar. c. Uncheck Auto Execute. d. Under Node 1 and Node 2, enter each node pair and click Apply: Node 1 and Node 4, Node 2 and Node 4, Node 3 and Node 4.

a

b

c d


WS15-12

Step 3. Define the Material

a

We will set aluminum as the material of the plate. a. Materials: Create / Isotropic / Manual Input. b. Select on Material Name and enter alum. c. Select Input Properties. d. Enter: Elastic Modulus: 10e6. Poisson Ratio: 0.33. Density: 0.1. e. OK. f. Apply.

d

b

c e f NAS102, Workshop 15, January 2004 Copyright© 2004 MSC.Software Corporation

WS15-13


Assign element properties to the model. a. Properties: Create / 1D / Rod. b. Enter prop_1 for the Property Set Name. c. Click Input Properties. d. Click in the Material Name icon, and select alum from the Material Property Sets box. e. Enter 1 for the Area. f. Click OK. g. Select the Beam Element icon. h. Shift-select Elm 1 3 (the left and right bar elements) and click Add. i. Click Apply.

a d e g

b

c h h

f

i NAS102, Workshop 15, January 2004 Copyright© 2004 MSC.Software Corporation

WS15-14

Step 4. Create Material Properties (cont.)

Assign element properties to the model. a. Enter prop_2 for the Property Set Name. b. Click Input Properties. c. Enter 2 for the Area. d. Click OK. e. Select Elm 2 (the middle bar element) and click Add. f. Click Apply.

c

a

b e e d


WS15-15


Assign the boundary constraints to the finite element model. a. Loads/BCs: Create / Displacement / Nodal b. Enter disp_1 for the New Set Name. c. Click Input Data. d. Input the value <0,0,0> for the Translation and <0,0,0> for the Rotation. e. Click OK. f. Click on Select Application Region. g. Change the Geometry Filter to FEM. h. Select Node 1:3 and click Add. i. Click OK. j. Click Apply.

a g

d

h h

b

e

c f

i j


WS15-16

Step 5. Create Load/Boundary Conditions (cont.) j

Assign the boundary constraints to the finite element model. a. Enter disp_2 for the New Set Name. b. Click Input Data. c. Change Translations to < , ,0> d. Click OK. e. Click on Select Application Region. f. Change the Geometry Filter to FEM. g. Select Node 4 and click Add. h. Click OK. i. Click Apply. j. Click Hide Labels.

a f c

g g

d b e

h i NAS102, Workshop 15, January 2004 Copyright© 2004 MSC.Software Corporation

WS15-17


Create a load case. a. Load Cases: Create. b. Enter case_1 for the Load Case Name. c. Click Assign/Prioritize Loads/BCs. d. Under Select Individual BCs, select Displ_disp_1 and Displ_disp_2. e. Click OK. f. Click Apply.

a d

b

c e f NAS102, Workshop 15, January 2004 Copyright© 2004 MSC.Software Corporation

WS15-18

Step 7. Create Model Variables

a Create model variables. a. Tools / Model Variables. b. Create / Variable / Property. c. Select 1D for Dimension and Rod for Type. d. Under Select Property Set, select prop_1 and prop_2. e. Under Select Property Name, select Area. f. Click Apply. g. Click Close.

b

c d

e


WS15-19

g

Step 8. Create Design Study

a Create a design study. a. Tools / Design Study. b. Create / Design Study. c. Enter opt_1 for the Design Study Name. d. Click Define Variables. e. Enter 0.1 for both lower bounds and 100 for both upper bounds. f. Click OK.

b

e

c

d


WS15-20

Step 8. Create Design Study (cont.)

Create a design study. a. Click Design Objective. b. Under Existing Objectives, select Total_Weight. c. Click OK. d. Click Design Constraints. e. Select Normal Modes for the Solution and Frequency for the Response. f. Enter FREQ_1 for the Constraint Name. g. Enter 1 for the Frequency Mode Number. h. Enter 1500 for the Lower Bound. i. Enter 1550 for the Upper Bound. j. Click Apply. k. Click Close. l. Click Apply. m. Click Close.

e

b f g c h

i

j

k

a d l


WS15-21

m


a

Generate the input file for analysis. a. Analysis: Optimize / Entire Model / Analysis Deck. b. Enter prob15 as the Job Name. c. Click Translation Parameters. d. Check XDB and Print. e. Click OK.

d

b

c


WS15-22


Generate the input file for analysis (cont.). a. Click on Optimization Parameters. b. Change the Mass Calculation to Coupled. c. Enter 0.00259 for Wt.Mass Conversion. d. Enter 30 for Maximum Number of Standard Design Cycles (DESMAX). e. Enter 1 for Print Design Data (P1) every n-th cycle where n =. f. Enter 1 for Print Analysis Results (NASPRT) every n-th cycle where n =. g. Click OK.


b c d

e f

g WS15-23

a


Generate the input file for analysis (cont.). a. Click on Subcases. b. Change the Solution Type to 103 NORMAL MODES. c. Under Available Subcases, select case_1. d. Click Apply. e. Click Cancel.

b c

a

e


WS15-24


Generate the input file for analysis (cont.). a. Click on Subcase Select. b. Change the Solution Type to 103 NORMAL MODES. c. Under Subcases Available, select case_1. d. Click OK. e. Click Apply.

b c

a d e NAS102, Workshop 15, January 2004 Copyright© 2004 MSC.Software Corporation

WS15-25




WS15-26


For MSC.Nastran users who created the input file using a text editor, the input file (prob15.dat) should be similar to the file below: ASSIGN OUTPUT2=’prob15.op2’, UNIT=12 ID NAS102, WORKSHOP 15 TIME 10 SOL 200 $ OPTIMIZATION CEND TITLE= SYMMETRIC THREE BAR TRUSS DESIGN OPTIMIZATION - VARIATION OF D200X1 SUBTITLE= GOAL IS TO MIN WT WHILE KEEPING THE 1ST MODE BETWEEN 1500-1550 HZ ECHO= SORT SPC= 100 DISP(PLOT) ALL DESOBJ(MIN)= 100 $ (DESIGN OBJECTIVE = DRESP ID) DESSUB= 200 $ DEFINE CONSTRAINT SET FOR BOTH SUBCASES SUBCASE 1 ANALYSIS= MODES METHOD= 10 BEGIN BULK $ $---------------------------------------------------------------------$ ANALYSIS MODEL $---------------------------------------------------------------------$ EIGRL, 10, , , 2 PARAM, POST, -1 PARAM, PATVER, 3.0 $ $ GRID DATA $ 2 3 4 5 6 7 8 9 10 GRID, 1, , -10.0, 0.0, 0.0 GRID, 2, , 0.0, 0.0, 0.0 GRID, 3, , 10.0, 0.0, 0.0 GRID, 4, , 0.0, -10.0, 0.0 $ SUPPORT DATA SPC, 100, 1, 123456, , 2, 123456 SPC, 100, 3, 123456, , 4, 3456 $ ELEMENT DATA CROD, 1, 11, 1, 4 CROD, 2, 12, 2, 4


WS15-27

Step 10: Review Input File for MSC.Nastran Users (cont.) CROD, 3, 13, 3, 4 $ PROPERTY DATA PROD, 11, 1, 1.0 PROD, 12, 1, 2.0 PROD, 13, 1, 1.0 MAT1, 1, 1.0E+7, , 0.33, 0.1 $ PARAM, WTMASS, .00259 $ $---------------------------------------------------------------------$ DESIGN MODEL $---------------------------------------------------------------------$ $...DESIGN VARIABLE DEFINITION $ $DESVAR,ID, LABEL, XINIT, XLB, XUB, DELXV(OPTIONAL) DESVAR, 1, A1, 1.0, 0.1, 100.0 DESVAR, 2, A2, 2.0, 0.1, 100.0 DESVAR, 3, A3, 1.0, 0.1, 100.0 $ $...IMPOSE X3=X1 (LEADS TO A3=A1) $ $DLINK, ID, DDVID, CO, CMULT, IDV1, C1, IDV2, C2, $+, IDV3, C3, ... DLINK, 1, 3, 0.0, 1.0, 1 1.00 $ $...DEFINITION OF DESIGN VARIABLE TO ANALYSIS MODEL PARAMETER RELATIONS $ $DVPREL1,ID, TYPE, PID, FID, PMIN, PMAX, CO, , $+, DVID1, COEF1, DVID2, COEF2, ... DVPREL1, 10, PROD, 11, 4, , , , , +DP1, 1, 1.0 DVPREL1, 20, PROD, 12, 4, , , , , +DP2, 2, 1.0 DVPREL1, 30, PROD, 13, 4, , , , , +DP3, 3, 1.0 $ $...STRUCTURAL RESPONSE INDENTIFICATION $ $DRESP1 ID LABEL RTYPE PTYPE REGION ATTA ATTB ATT1 $+ ATT2 ... DRESP1 100 W WEIGHT


WS15-28

+

+ +DP1 +DP2 +DP3

+

Step 10: Review Input File for MSC.Nastran Users (cont.) DRESP1 210 MODE1 EIGN 1 $ $...CONSTRAINTS $ $DCONSTR,DCID, RID, LALLOW, UALLOW DCONSTR, 200, 210, 8.883E7, 9.485E7 $ $...OPTIMIZATION CONTROL $ DOPTPRM, DESMAX, 30 $ $.......2.......3.......4.......5.......6.......7.......8.......9.......0 ENDDATA


WS15-29


Windows Users:




WS15-30


Unix Users:




WS15-31



While still editing prob15.f06, search for the word DESIGN VARIABLE HISTORY. Design Variable

Initial Value

Optimization Value

Iteration Value

1

__________

___________

__________

2

__________

___________

__________

3

__________

___________

__________


WS15-32




WS15-33




WS15-34

Step 13. Read Output File

Read the .op2 output file. a. Analysis: Access Results / Read Output2 / Result Entities. b. Click on Select Results File. c. Select prob15.op2. d. Click OK. e. Click Apply.

a

c

d

b


WS15-35


a

Create a X-Y Plot of the results. a. XY-Plot: Post / XYWindow b. Under Select Current XY Window, select DesignVariableHistory. c. Under Post/Unpost XYWindows, select DesignVariableHistory. d. Click Apply.

b

c


WS15-36


a

Create a X-Y Plot of the results. a. Under Select Current XY Window, select ObjectiveFunctionHistory. b. Under Post/Unpost XYWindows, select ObjectiveFunctionHistory. c. Click Apply.

b

c


WS15-37


a

Create a X-Y Plot of the results. a. Under Select Current XY Window, select MaximumConstraintHistory. b. Under Post/Unpost XYWindows, select MaximumConstraintHistory. c. Click Apply.

b

c


WS15-38

APPENDIX 1a MODAL ANALYSIS OF A BEAM

NAS102, Appendix 1a, January 2004 Copyright© 2004 MSC.Software Corporation

AP1a-1


AP1a-2

Appendix 1a – Modal Analysis of a Beam (SI Units)

Objectives

Perform normal modes analysis of a beam. Submit the file for analysis in MSC.Nastran. Find the first three natural frequencies and mode shapes of the beam.


AP1a-3


Model Description

The goal of this example is to find the first 3 modes of a beam pinned at both ends. The figure below is a finite element representation of the beam. One end is constrained in all translations and the other is free to move in the X. Both ends are held in the X-rotation.

Figure 1a.1 Loads and Boundary Conditions


AP1a-4


Hand Calculations:

From Theory:

Table 1a.1


AP1a-5


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Explicitly generate a finite element representation of the beam structure. (i.e. the grids (GRID) and element connectivities (CBAR) should be defined manually.) 2. Define material (MAT1) and element (PBAR) properties. 3. Apply the fixed boundary constraints (SPC1). 4. Prepare the model for a normal modes analysis (SOL 103) and PARAMS. z PARAM, COUPMASS, 1 z EIGRL (To select Lanczos)

5. Generate an input file and submit it to the MSC.Nastran solver for normal modes analysis. 6. Review the results, specifically the eigenvalues.


AP1a-6

Appendix 1a – Modal Analysis of a Beam (SI Units) ID SEMINAR, PROB1A _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


AP1a-7

Appendix 1a – Modal Analysis of a Beam (SI Units) 1

2

3


4

5

6

AP1a-8

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Appendix 1a – Modal Analysis of a Beam (SI Units) 1

2

3

4

5

6

ENDDATA


AP1a-9

7

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10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Create a new database. Create the geometry. Create a finite element mesh. Create load/boundary conditions. Define the material. Create material properties. Create an input file. Review the input file for MSC.Nastran users. Submit the input file to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. View results.


AP1a-10


a

d Create a new database named probap1a.db. a. File / New. b. Enter probap1a as the file name. c. Click OK. d. Choose Default Tolerance. e. Select MSC.Nastran as the Analysis Code. f. Select Structural as the Analysis Type. g. Click OK.


e f c

b

AP1a-11

g

Step 2. Create Geometry

Create a curve. a. Geometry: Create / Curve / XYZ. b. Enter <1000 0 0> for the Vector Coordinate List. c. Uncheck Auto Execute. d. Enter [0 0 0] for the Origin Coordinates List. e. Click Apply.

a

b c d e


AP1a-12

Step 3. Create Element Mesh

Create the finite element model and mesh the surface a. Elements: Create / Mesh / Curve. b. Enter 100 for the Global Edge Length. c. For Curve List, select the curve that was just created. d. Click Apply.

a

c b

d


AP1a-13

Step 4. Create Loads/Boundary Conditions

Assign the boundary constraints to the finite element model. a. Loads/BCs: Create / Displacement / Nodal b. Enter disp1 for the New Set Name. c. Click Input Data. d. Input the value <0,0,0> for the Translation and <0, ,> for the Rotation. e. Click OK. f. Click on Select Application Region. g. Change the Geometry Filter to Geometry. h. Select the leftmost point (Point 1). i. Click Add and OK. j. Click Apply.

a g

d

h i

b

e

c

i

f j


AP1a-14

Step 4. Create Loads/Boundary Conditions (cont.)

Assign the boundary constraints to the finite element model. a. Enter disp2 for the New Set Name. b. Click Input Data. c. Input the value <,0,0> for the Translation and <0, ,> for the Rotation. d. Click OK. e. Click on Select Application Region. f. Change the Geometry Filter to Geometry. g. Select the rightmost point (Point 2). h. Click Add and OK. i. Click Apply.

f

c

g h

a

d b e

h i NAS102, Appendix 1a, January 2004 Copyright© 2004 MSC.Software Corporation

AP1a-15

Step 4. Create Loads/Boundary Conditions (cont.)

Assign the boundary constraints to the finite element model. a. Enter permanent_constraint for the New Set Name. b. Click Input Data. c. Input the value <, ,0> for the Translation and <0,0,> for the Rotation. d. Click OK. e. Click on Select Application Region. f. Select the curve. g. Click Add and OK. h. Click Apply.

c

f g

a

d b e

g h NAS102, Appendix 1a, January 2004 Copyright© 2004 MSC.Software Corporation

AP1a-16

Step 5. Define Material

Create the material properties. a. Materials: Create / Isotropic / Manual Input. b. Enter mat_1 for the Material Name. c. Click Input Properties. d. Enter 2.0684e5 for the Elastic Modulus and 0.32 for Poisson Ratio. e. Enter 7.8334e-9 for the Density. f. Click OK. g. Click Apply.

a d e

b

c g f


AP1a-17

Step 6. Create Properties

Assign element properties to the model. a. Properties: Create / 1D / Beam. b. Enter bar for the Property Set Name. c. Click Input Properties. d. Click in the Material Name icon, and select mat_1 from the Material Property Sets box. e. Enter Coord 0.2 for the Bar Orientation. f. Enter 5e3 for the Area, 1.0417e6 for Inertia[1,1], and 1.0 for Inertia[2,1]. g. Click OK. h. Select Curve 1 in the Select Members box and click Add. i. Click Apply.

a

d e

b f c h h g i


AP1a-18


a

Generate the input file for analysis. a. Analysis: Analyze / Entire Model / Analysis Deck. b. Enter probap1a as the Job Name. c. Click on Solution Type. d. Select Normal Modes as the Solution Type. e. Click on Solution Parameters. f. Change the Mass Calculation to Coupled. g. Click OK. h. Click OK.

d f

b e

c h g NAS102, Appendix 1a, January 2004 Copyright© 2004 MSC.Software Corporation

AP1a-19


Generate the input file for analysis (cont.). a. Click on Subcases. b. Select Default from the Available Subcases field. c. Click on Subcase Parameters. d. Change the Number of Desired Roots to 3. e. Click OK. f. Click Apply. g. Click Cancel. h. Click Apply.

b

d

c

a

e f NAS102, Appendix 1a, January 2004 Copyright© 2004 MSC.Software Corporation

AP1a-20

g

h


An MSC.Nastran input file called probap1a.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to step 9.


AP1a-21


For MSC.Nastran users who created the input file using a text editor, the input file (probap1a.dat) should be similar to the file below: SOL 103 TIME 600 CEND TITLE = Normal Modes Example (SI SUBCASE 1 METHOD = 1 SPC = 1 VECTOR(SORT1,REAL)=ALL BEGIN BULK PARAM COUPMASS1 EIGRL 1 PBAR 1 1 5000. CBAR 1 1 1 CBAR 2 1 2 CBAR 3 1 3 CBAR 4 1 4 CBAR 5 1 5 CBAR 6 1 6 CBAR 7 1 7 CBAR 8 1 8 CBAR 9 1 9 CBAR 10 1 10 MAT1 1 206840. GRID 1 0. GRID 2 100.000 GRID 3 200.000 GRID 4 300.000 GRID 5 400.000 GRID 6 500. GRID 7 600.000 GRID 8 700.000 GRID 9 800.000 GRID 10 900.000 GRID 11 1000. SPC1 1 1234 1 SPC1 1 234 11 ENDDATA


AP1a-22

UNITS)

3 1.04+6 2 3 4 5 6 7 8 9 10 11 .32 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.

0 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 7.83-9 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.

1. 1. 1. 1. 1. 1. 1. 1. 1. 1.

0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 345 345 345 345 345 345 345 345 345 345 345


Windows Users:


Double click on MSC.Nastran icon. Select probap1a.bdf or probap1a.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


AP1a-23


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran probap1a.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran probap1a scr=yes. Monitor the run using the UNIX ps command.


AP1a-24


When the run is completed, edit the probap1a.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.

While still editing probap1a.f06, search for the word E I G E N (spaces are necessary) What are the first 3 modes? Frequency 1st = ___________ Hz 2nd = ___________ Hz 3rd = ___________ Hz


AP1a-25





AP1a-26

Step 11. Attach XDB File

Attach the XDB file. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click on Select Results File. c. Select probap1a.xdb. d. Click OK. e. Click Apply.

a c

d

b e NAS102, Appendix 1a, January 2004 Copyright© 2004 MSC.Software Corporation

AP1a-27


a

Plot deformation. a. Results: Create / Deformation. b. Under Select Result case(s), select Default, A1:Mode 1: Freq. = 116.51 c. Under Select Deformation Result, select Eigenvectors, Translational. d. Click Apply.

b

c

You may select any result case along with fringe and deformation results if you are interested.

d NAS102, Appendix 1a, January 2004 Copyright© 2004 MSC.Software Corporation

AP1a-28

APPENDIX 1b NORMAL MODES WITH DIFFERENTIAL STIFFNESS

NAS102, Appendix 1b, January 2004 Copyright© 2004 MSC.Software Corporation

AP1b-1


AP1b-2

Appendix 1b – Normal Modes with Differential Stiffness

Objectives

Analyze a stiffened beam for normal modes. Produce a MSC.Nastran input file that represents the beam and load. Submit the input file to MSC.Nastran for analysis. Find the normal modes (natural frequencies).


AP1b-3


Model Description

The goal of this example is to analyze a stiffened model. In this case, the model is the beam from Appendix 1a with 1x107 N of force applied. This is no longer a simple normal modes analysis. Instead, we will be using a nonlinear static solution (SOL 106) with PARAM, NMLOOP, METHOD and EIGRL.

Figure 1b.1 Grid Coordinates and Element Connectivities


AP1b-4


Theoretical solution:

Table 1b.1

For static load:


AP1b-5


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. 2. 3. 4.

Open the database created in Appendix 1a. Apply a force load to one end of the model. Ensure that the analysis is set to nonlinear static (SOL 106). Prepare nonlinear analysis to also analyze for normal modes (PARAM NMLOOP, EIGRL, PARAM LGDISP, NLPARM). 5. Review the results, specifically the eigenvectors.


AP1b-6

Appendix 1b – Normal Modes with Differential Stiffness ID SEMINAR, PROB1B _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


AP1b-7

Appendix 1b – Normal Modes with Differential Stiffness 1

2

3


4

5

6

AP1b-8

7

8

9

10

Appendix 1b – Normal Modes with Differential Stiffness 1

2

3

4

5

6

ENDDATA


AP1b-9

7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8.

Open an existing database. Create loads/boundary conditions. Create an input file. Review the input file for MSC.Nastran users. Submit the input file to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. View results.


AP1b-10

Step 1. Open Database

a

Open the database probap1a.db. a. File / Open. b. Enter probap1a as the file name. c. Click OK.

b

c


AP1b-11

Step 2. Create Loads/Boundary Conditions

Create the force load. a. Loads/BCs: Create / Force / Nodal. b. Enter pull for the New Set Name. c. Click on the Input Data button. d. Enter <1e7, ,> for Force. e. Click OK. f. Click on Select Application Region. g. Select the rightmost point (Point 2). h. Click Add, and click OK. i. Click Apply.

a d

g h

b e c f

h i NAS102, Appendix 1b, January 2004 Copyright© 2004 MSC.Software Corporation

AP1b-12


Generate the input file for analysis. a. Enter probap1b as the Job Name. b. Click on Solution Type. c. Select Nonlinear Static as the Solution Type. d. Click on Solution Parameters. e. Change the Mass Calculation to Coupled. f. Click OK. g. Click OK.

c

e

a d

g

f


AP1b-13

b


Generate input file for analysis (cont.). a. Click on Direct Text Input. b. Select the Case Control Section. c. Enter METHOD=10 in the above field. d. Select the Bulk Data Section. e. In the above field, enter PARAM, NMLOOP, 5 on the first line, then EIGRL, 10,,, 3 on the next line. f. Click OK.

c

b

e

a

d f NAS102, Appendix 1b, January 2004 Copyright© 2004 MSC.Software Corporation

AP1b-14


Generate the input file for analysis (cont.). a. Click on Subcases. b. Select Default from the Available Subcases field. c. Click on Subcase Parameters. d. Change the Number of Load Increments to 5. e. Click OK. f. Click Apply. g. Click Cancel. h. Click Apply.

d b

c

a

e f NAS102, Appendix 1b, January 2004 Copyright© 2004 MSC.Software Corporation

AP1b-15

g

h


An MSC.Nastran input file called probap1b.bdf has been generated. The process of translating the model into an input file is called Forward Translation. The Forward Translation is complete when the Heartbeat turns green. MSC.Patran Users should proceed to step 5.


AP1b-16


For MSC.Nastran users who created the input file using a text editor, the input file (probap1b.dat) should be similar to the file below:

SOL 106 TIME 600 CEND $ TITLE = NORMAL MODES WITH DIFFERENTIAL STIFFNESS METHOD = 10 SUBCASE 1 NLPARM = 1 SPC = 1 LOAD = 1 DISPLACEMENT(SORT1,REAL)=ALL $ BEGIN BULK PARAM COUPMASS 1 PARAM LGDISP 1 NLPARM 1 5 AUTO 5 NO + A + A .001 1.-7 PARAM,NMLOOP,5 $ EIGRL,10,,,3 PBAR 1 1 5000. 1.04+6 CBAR 1 1 1 2 0. CBAR 2 1 2 3 0. CBAR 3 1 3 4 0. CBAR 4 1 4 5 0. CBAR 5 1 5 6 0. CBAR 6 1 6 7 0. CBAR 7 1 7 8 0. CBAR 8 1 8 9 0. CBAR 9 1 9 10 0. CBAR 10 1 10 11 0. $ MAT1 1 206840. .32 7.83-9 GRID 1 0. 0. 0. GRID 2 100.000 0. 0.


GRID GRID GRID GRID GRID GRID GRID GRID GRID SPC1 SPC1 FORCE ENDDATA

25

PW

1. 1. 1. 1. 1. 1. 1. 1. 1. 1.

0. 0. 0. 0. 0. 0. 0. 0. 0. 0.

345 345

AP1b-17

3 4 5 6 7 8 9 10 11 1 1 1

1234 234 11

200.000 300.000 400.000 500. 600.000 700.000 800.000 900.000 1000. 1 11 0

0. 0. 0. 0. 0. 0. 0. 0. 0.

0. 0. 0. 0. 0. 0. 0. 0. 0.

1.+7

1.

345 345 345 345 345 345 345 345 345

0.

0.


Windows Users:


Double click on MSC.Nastran icon. Select probap1b.bdf or probap1b.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


AP1b-18


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran probap1b.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran probap1b scr=yes. Monitor the run using the UNIX ps command.


AP1b-19


When the run is completed, edit the probap1b.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.

While still editing probap1b.f06, search for the word E I G E N (spaces are necessary) What are the first 3 natural frequencies? Frequency 1st = ___________ Hz 2nd = ___________ Hz 3rd = ___________ Hz


AP1b-20





AP1b-21

Step 7. Attach XDB File

Attach the XDB file. a. Analysis: Access Results / Attach XDB / Result Entities. b. Click on Select Results File. c. Select probap1b.xdb. d. Click OK. e. Click Apply.

a

c

d

b

e NAS102, Appendix 1b, January 2004 Copyright© 2004 MSC.Software Corporation

AP1b-22


a

Plot displacement results. a. Results: Create / Deformation. b. Under Select Result case(s), select Default, A2: Mode 1 : Freq. = 278.21 c. Under Select Deformation Result, select Eigenvectors, Translational. d. Click Apply.

b

c

You may select any result case along with fringe and deformation results if you are interested.

d NAS102, Appendix 1b, January 2004 Copyright© 2004 MSC.Software Corporation

AP1b-23


AP1b-24

APPENDIX 1c NORMAL MODES WITH DIFFERENTIAL STIFFNESS, USING STATSUB

NAS102, Appendix 1c, January 2004 Copyright© 2004 MSC.Software Corporation

AP1c-1


AP1c-2

Appendix 1c – Normal Modes with Differential Stiffness, Using STATSUB

Objectives

Perform normal modes analysis of a simply supported beam with differential stiffness. Utilize the MSC.Nastran STATSUB feature. Find the first three natural frequencies and mode shapes of the beam.


AP1c-3


Model Description

The goal of this example is to determine normal modes with differential stiffness by using the MSC.Nastran STATSUB feature. The figure below is a finite element representation of the beam. One end is constrained in all translation and the other is free to move in the X. Both ends are held in the X-rotation.

Figure 1c.1 Grid Coordinates and Element Connectivities


AP1c-4


Theoretical solution:

Table 1c.1

For static load:


AP1c-5


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Explicitly generate a finite element representation of the beam structure (i.e. the grids (GRID) and element connectivities (CBEAM) should be defined manually). 2. Define material (MAT1) and element (PBAR) properties. 3. Apply the fixed boundary constraints (SPC1). 4. Prepare the model for normal modes analysis (SOL 103 and PARAMs). z PARAM WTMASS 0.00259 z PARAM COUPMASS 1 z EIGRL (To select Lanczos)

5. Generate an input file and submit it to the MSC.Nastran solver for normal modes analysis. 6. Review the results, specifically the eigenvalues.


AP1c-6

Appendix 1c – Normal Modes with Differential Stiffness, Using STATSUB ID SEMINAR, PROB1C _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


AP1c-7

Appendix 1c – Normal Modes with Differential Stiffness, Using STATSUB 1

2

3


4

5

6

AP1c-8

7

8

9

10

Appendix 1c – Normal Modes with Differential Stiffness, Using STATSUB 1

2

3

4

5

6

ENDDATA


AP1c-9

7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6.

Open an existing database. Create an input file. Review the input file for MSC.Nastran users. Modify the input file. Submit the input file to MSC.Nastran for analysis. Review the .F06 file.


AP1c-10

Step 1. Open Database

a

Open the database probap1a.db. a. File / Open. b. Enter probap1a as the file name. c. Click OK.

b

c


AP1c-11


Generate the input file for analysis. a. Enter probap1c as the Job Name. b. Click on Solution Type. c. Select Linear Static as the Solution Type. d. Click on Solution Parameters. e. Change the Mass Calculation to Coupled. f. Click OK. g. Click OK.

c

e

a d b f


g

AP1c-12


Generate input file for analysis (cont.). a. Click on Direct Text Input. b. Select the Case Control Section. c. Click Clear. d. Select the Bulk Data Section. e. Click Clear. f. Click OK. g. Click Apply.

b c

An MSC.Nastran input file called probap1c.bdf has been generated.

a d f NAS102, Appendix 1c, January 2004 Copyright© 2004 MSC.Software Corporation

e AP1c-13


For MSC.Nastran users who created the input file using a text editor, the input file (probap1c.dat) should be similar to the file below:

SOL 101 CEND ECHO = NONE SUBCASE 1 SPC = 2 LOAD = 2 DISPLACEMENT(SORT1,REAL)=ALL SPCFORCES(SORT1,REAL)=ALL STRESS(SORT1,REAL,VONMISES,BILIN)=ALL BEGIN BULK PARAM POST -1 PARAM PATVER 3. PARAM AUTOSPC NO PBAR 1 1 5000. 1.041+6 CBAR 1 1 1 2 CBAR 2 1 2 3 CBAR 3 1 3 4 CBAR 4 1 4 5 CBAR 5 1 5 6 CBAR 6 1 6 7 CBAR 7 1 7 8 CBAR 8 1 8 9 CBAR 9 1 9 10 CBAR 10 1 10 11 MAT1 1 206840. .32 GRID 1 0. 0. GRID 2 100.000 0. GRID 3 200.000 0. GRID 4 300.000 0. GRID 5 400.000 0. GRID 6 500. 0. GRID 7 600.000 0. GRID 8 700.000 0. GRID 9 800.000 0. GRID 10 900.000 0.

GRID 11 SPCADD 2 LOAD 2 SPC1 1 SPC1 3 SPC1 4 FORCE 1 ENDDATA 052ec265

1. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 7.833-9 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.


1. 1. 1. 1. 1. 1. 1. 1. 1. 1.

0. 0. 0. 0. 0. 0. 0. 0. 0. 0.

AP1c-14

1 1. 1234 234 345 11

1000. 3 1. 1 11 1 0

0. 4 1

0.

THRU 1.+7

11 1.

0.

0.

Step 5: Modify Input File

Before submitting the input file for analysis, modifications must be made to it in order to perform normal mode analysis with differential stiffness. Add in the appropriate commands within the .bdf file by doing the following: 1. 2. 3.

4.

5.

Open the input file, probap1c.bdf, using any text editor. Locate and replace the text SOL 101 with SOL 103. Add a new subcase after the SUBCASE 1 section and before the BEGIN BULK line: SUBCASE 2 STATSUB = 1 METHOD = 1 SPC = 2 VECTOR = ALL Add the following after the BEGIN BULK line: EIGRL, 1, , ,3 Save the changes to the .bdf file and close the text editor. You are now ready to submit the input file for analysis.


AP1c-15


Windows Users:


Double click on MSC.Nastran icon. Select probap1c.bdf or probap1c.dat and click Open. Enter scr=yes in the Optional Keywords field. Click Run.


AP1c-16


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran probap1c.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran probap1c scr=yes. Monitor the run using the UNIX ps command.


AP1c-17


When the run is completed, edit the probap1c.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.

While still editing probap1c.f06, search for the word R E A L (spaces are necessary) What are the first 3 modes? Frequency 1st = ___________ Hz 2nd = ___________ Hz 3rd = ___________ Hz


AP1c-18




AP1c-19


AP1c-20

APPENDIX 7 DIRECT TRANSIENT RESPONSE WITH BASE EXCITATION

NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-1


AP7-2

Appendix 7 – Direct Transient Response With Base Excitation

Objectives

Define time-varying unit acceleration. Use the large mass method. Produce a MSC.Nastran input file from a dynamic math model, created in Workshop 1. Submit the file for analysis in MSC.Nastran. Compute nodal displacements for the desired time domain.


AP7-3


Model Description

Using the direct method, determine the transient response to a unit acceleration sine pulse of 250Hz applied at the base in the z direction. A large mass of 1000lb is applied to the base. Use structural damping of g=0.06 and convert this damping to equivalent viscous damping at 250Hz.



AP7-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Modify base constraints and release displacements in the Z-direction. 3. Define the time-varying unit acceleration (TLOAD2 and DAREA). 4. Create the large mass at the base (CMASS2 and RBE2). 5. Specify the structural damping and convert this damping to equivalent viscous damping. z PARAM, G, 0.06 z PARAM, W3, 1571 6. Specify integration time steps (TSTEP). 7. Prepare the model for a direct transient analysis (SOL 109). 8. Request response in terms of nodal displacement at grids 11, 33, and 55. 9. Generate an input file and submit it to the MSC.Nastran solver for enforced motion using direct transient analysis. 10. Review the results, specifically the nodal displacements, velocities, and acceleration.


AP7-5

Appendix 7 – Direct Transient Response With Base Excitation ID SEMINAR, PROB7 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


AP7-6

Appendix 7 – Direct Transient Response With Base Excitation 1

2

3


4

5

6

AP7-7

7

8

9

10

Appendix 7 – Direct Transient Response With Base Excitation 1

2

3

4

5

6

ENDDATA


AP7-8

7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Create a new database. Import an existing model. Create a load case. Create a 0D mass. Create a RBE2 to connect the mass to the plate. Create time dependent fields. Create load/boundary conditions. Create a MSC.Nastran input file. Review the MSC.Nastran input file. Submit the input file to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. View results.


AP7-9


a



e f c

b

AP7-10

g


e

f

a b

c

c

Import the model from a Nastran Input File. a. File / Import. b. Select MSC.Nastran Input as the Source. c. Select plate.bdf and click Apply. d. Click OK when the Nastran Input File Import Summary appears. e. Click Show Labels. f. Switch to Iso 3 View.

d d NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-11



a e

b c

d

f g NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-12

Step 4. Create 0D Mass

Create a point element. a. Elements: Create / Element / Edit. b. Select Point for the Shape. c. Select the center node on the left edge of the plate (Node 23).

a

b

c


AP7-13

Step 4. Create 0D Mass (cont.)

Create the 0D mass. a. Properties: Create / 0D / Mass. b. Enter scalar_mass for the Property Set Name. c. Select Grounded for Options. d. Click Input Properties. e. Enter 1000 for the Mass. f. Select UZ for Dof at Node 1. g. Click OK. h. Click in the Select Members box, click the Point Element icon, select the previously created point element (Elm 41), and click Add. i. Click Apply.

a e f h

b c d h h

g

i NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-14

Step 5. Create a RBE2

Create a RBE2 to tie the mass to the drive point. a. Elements: Create / MPC / RBE2. b. Click Define Terms. c. Select Create Independent. d. Turn Auto Execute off. e. Select the node with the point element (Node 23). f. Click Apply. g. Select 4 nodes on the left edge of the plate, excluding the center node (Nodes 1, 12, 34 and 35). h. Select UZ for DOFs. i. Click Apply. j. Click Cancel. k. Click Apply.


a

b k c d g

e

h i

j

AP7-15

f


Create a time-dependent non-spatial field. a. Fields: Create / Non Spatial / Tabular Input b. Enter time_dependent_acceleration for the Field Name. c. Click [Options…]. d. Enter 21 for Maximum Value of t. e. Click OK.

a

b d

e


AP7-16

c



h

i

g

j

f


AP7-17



k

l

m NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-18


Create the time-dependent unit acceleration. a. Loads/BCs: Create / Acceleration / Nodal. b. Enter unit_acceleration for the New Set Name. c. Click on the Input Data button. d. Enter <0, 0, 2.588> for Trans. Accel., and select time_dependent_acc eleration for the Time/Freq. Dependent Field. e. Click OK. f. Click on Select Application Region. g. Choose FEM h. Select the center node on the left side of the plate (Node 23). i. Click Add, and click OK. j. Click Apply.

a

d

d

g

h i


b e

c i

f j AP7-19


Modify the original constraint from the imported database. a. Loads/BCs: Modify / Displacement / Nodal. b. Click on spc1.1 in the Select Set to Modify box to select it. c. Click on the Modify Data button. d. Modify Translations to <0,0,>. e. Click OK. f. Click Apply.

a d

b

e

e c f NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-20


a


d

b

c

e NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-21


Generate the input file for analysis (cont.). a. Click on Solution Type. b. Select Transient Response. c. Change the Formulation to Direct. d. Click on Solution Parameters. e. Change the Mass Calculation to Coupled. f. Enter 0.00259 for WtMass Conversion.

e

b f

g. Enter 0.06 for Struct. Damping Coefficient and 1571 for W3, Damping Factor. h. Click OK. i. Click OK.

i

h NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

c d

g

AP7-22

a



d b

g

e. Change No. of Time Steps to 200, and Delta-T to 0.0002. f. Click OK. g. Click OK.

e c a

f NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-23


Generate the input file for analysis (cont.). a. Click on Output Requests. b. Under Output Requests, select SPCFORCES(SORT2, REAL)=All FEM and click Delete. c. Under Select Result Type, select Velocities and Accelerations. d. Click OK. e. Click Apply. f. Click Cancel.

c

b

a b

d NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-24

e

f



b

b

c a d NAS102, Appendix 7, January 2004 Copyright© 2004 MSC.Software Corporation

AP7-25




AP7-26



ID SEMINAR, PROB7 SOL 109 TIME 30 CEND TITLE = TRANSIENT RESPONSE WITH BASE EXCITATION SUBTITLE = USING DIRECT TRANSIENT METHOD, NO REDUCTION ECHO = UNSORTED SPC = 200 SET 111 = 23, 33 DISPLACEMENT (SORT2) = 111 VELOCITY (SORT2) = 111 ACCELERATION (SORT2) = 111 SUBCASE 1 DLOAD = 500 TSTEP = 100 $ OUTPUT (XYPLOT) XGRID=YES YGRID=YES XTITLE= TIME (SEC) YTITLE= BASE ACCELERATION XYPLOT ACCELERATION RESPONSE / 23 (T3) YTITLE= BASE DISPLACEMENT XYPLOT DISP RESPONSE / 23 (T3) YTITLE= TIP CENTER DISPLACEMENT RESPONSE XYPLOT DISP RESPONSE / 33 (T3) $ BEGIN BULK $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $ INCLUDE ’plate.bdf’ PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $


$ SPECIFY STRUCTURAL DAMPING $ PARAM, G, 0.06 PARAM, W3, 1571. $ $ APPLY EDGE CONSTRAINTS $ SPC1, 200, 12456, 1, 12, 23, 34, 45 $ $ PLACE BIG FOUNDATION MASS (BFM) AT BASE $ CMASS2, 100, 1000., 23, 3 $ $ RBE MASS TO REMAINING BASE POINTS $ RBE2, 101, 23, 3, 1, 12, 34, 45 $ $ APPLY LOADING TO FOUNDATION MASS $ TLOAD2, 500, 600, , 0, 0.0, 0.004, 250., -90. $ DAREA, 600, 23, 3, 2.588 $ $ SPECIFY INTEGRATION TIME STEPS $ TSTEP, 100, 200, 2.0E-4, 1 $ ENDDATA

AP7-27


Windows Users:




AP7-28


Unix Users:


To submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob7.bdf scr=yes. Monitor the run using the UNIX ps command. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob7a scr=yes. Monitor the run using the UNIX ps command.


AP7-29




T3

0

= ___________

.02

= ___________

.04

= ___________


AP7-30


T3

0

= ___________

.02

= ___________

.04

= ___________

Now search for the word V E L O C (spaces are necessary) Velocity at Grid 23 Time

T3

0

= ___________

.02

= ___________

.04

= ___________


AP7-31

Step 11: Review F06 File (cont.) Velocity at Grid 33 Time

T3

0

= ___________

.02

= ___________

.04

= ___________

Now search for the word A C C E L (spaces are necessary) Acceleration at Grid 23 Time

T3

0

= ___________

.02

= ___________

.04

= ___________


AP7-32

Step 11: Review F06 File (cont.) Acceleration at Grid 33 Time

T3

0

= ___________

.02

= ___________

.04

= ___________


AP7-33




AP7-34




AP7-35



a

c

d

b


AP7-36



a

b c

d

f

e


AP7-37


Create a X-Y graph of displacement results (cont.). a. Select Displacement, Translational for the Select Y Result field. b. Select Z Component as the Quantity. c. Click on the Target Entities icon. d. Change the Target Entity Selection to Nodes. e. Select the center node on the left edge of the plate (Node 23). f. Click Apply.

c

d e

a

b f


AP7-38


Base Displacement at Node 23


AP7-39



Tip Displacement at Node 33

a

b


AP7-40


Create a X-Y graph of displacement results (cont.). a. Click Select Results. b. Under Select Y Result, select Velocities, Translational. c. Click Target Entities. d. Select the center node on the left edge of the plate (Node 23). e. Click Apply.

a

c

d

b

e


AP7-41


Base Velocity at Node 23


AP7-42



Tip Velocity at Node 33

a

b


AP7-43


Create a X-Y graph of displacement results (cont.). a. Click Select Results. b. Under Select Y Result, select Accelerations, Translational. c. Click Target Entities. d. Select the center node on the left edge of the plate (Node 23). e. Click Apply.

a

c

d

b

e


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Base Acceleration at Node 23


AP7-45



Tip Acceleration at Node 33

a

b


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APPENDIX 8 ENFORCED MOTION WITH DIRECT FREQUENCY RESPONSE


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AP8-2

Appendix 8 – Enforced Motion with Direct Frequency Response

Objectives

Define frequency-varying tip displacement. Use the large mass method. Produce a MSC.Nastran input file from a dynamic math model created in Workshop 1. Submit the file for analysis in MSC.Nastran. Compute nodal displacements for desired time domain.


AP8-3


Model Description

Using the direct method, determine the frequency response of the flat rectangular plate, created in Workshop 1, under a 0.1 displacement at a corner of the tip. Use a frequency step of 20 Hz between a range of 20 and 1000Hz. Use structural damping of g=0.06.



AP8-4


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor 1. Reference previously created dynamic math model, plate.bdf, by using the INCLUDE statement. 2. Create the large mass at a corner of the tip (CMASS2). 3. Define the frequency-varying tip displacement (RLOAD2, TABLED4, DAREA). 4. Define a set of frequencies to be used in the solution (FREQ1). 5. Prepare the model for a direct frequency response analysis (SOL 108). 6. Specify the structural damping z PARAM, G, 0.06 7. Request response in terms of nodal displacement at grid points 11, 33, and 55. 8. Generate an input file and submit it to the MSC.Nastran solver for frequency response analysis. 9. Review the results, specifically the nodal displacements.


AP8-5

Appendix 8 – Enforced Motion with Direct Frequency Response ID SEMINAR, PROB8 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULK


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Appendix 8 – Enforced Motion with Direct Frequency Response 1

2

3


4

5

6

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7

8

9

10

Appendix 8 – Enforced Motion with Direct Frequency Response 1

2

3

4

5

6

ENDDATA


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7

8

9

10



MSC.Patran Users 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Create a new database. Import an existing model. Create a load case. Create a 0D mass. Create a MSC.Nastran input file. Review the MSC.Nastran input file. Submit the input file to MSC.Nastran for analysis. Review the .F06 file. Attach the XDB file. View results.


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a



e f g b

c

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e

a b

c

c


d d NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

AP8-11


Create a frequency-dependent load case called frequency_response. a. Load Cases: Create. b. Enter frequency_response for the Load Case Name. c. Change the Load Case Type to Time Dependent. d. Click Assign/Prioritize Loads/BCs. e. Select Displ_spc1.1. f. Click OK. g. Click Apply.

a e

b c

d f g NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

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Step 4. Create 0D Mass

Create a point element. a. Elements: Create / Element / Edit. b. Select Point for the Shape. c. Select the node in the lower right corner (Node 11).

a

b

c


AP8-13

Step 4. Create 0D Mass (cont.)

Create the 0D mass. a. Properties: Create / 0D / Mass. b. Enter scalar_mass for the Property Set Name. c. Select Grounded for Options. d. Click Input Properties. e. Enter 1.0e5 for the Mass. f. Select UZ for Dof at Node 1. g. Click OK. h. Click in the Select Members box, click the Point Element icon, select the previously created point element (Elm 41), and click Add. i. Click Apply.

a e f h

b c d h h

g

i NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

AP8-14


a


d

b

c


AP8-15


Generate the input file for analysis (cont.). a. Click on Solution Type. b. Select Frequency Response. c. Change the Formulation to Direct. d. Click on Solution Parameters. e. Change the Mass Calculation to Coupled. f. Enter 0.00259 for WtMass Conversion.

e b

f

g. Enter 0.06 for Struct. Damping Coefficient. h. Click OK. i. Click OK.

c d

g

a i h


AP8-16


Generate the input file for analysis (cont.). a. Click on Direct Text Input. b. Under the Bulk Data Section, enter the text below into the field: RLOAD2,500,600,,,310 TABLED4,310,0.,1.,0.,10000, +,0.,0.,-39.4784,ENDT DAREA,600,11,3,25.8799 c. Click on the Case Control Section. d. Enter DLOAD=500 in the field. e. Click OK.

b

d

a c e NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

AP8-17


Generate the input file for analysis (cont.). a. Click on Subcases. b. Select frequency_response from the Available Subcases field. c. Click on Subcase Parameters. d. Click on DEFINE FREQUENCIES button.

d b

g

e. Enter 20 for the start freq., 1000 for the end freq., and 49 for the number of increments. f. Click OK. g. Click OK.

e c a

f NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

AP8-18


Generate the input file for analysis (cont.). a. Click on Output Requests. b. Under Output Requests, select SPCFORCES(SORT1, REAL)=All FEM and click Delete. c. Click OK. d. Click Apply. e. Click Cancel.

b

a b

c NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

d AP8-19

e


Generate the input file for analysis (cont.). a. Click on Subcase Select. b. Select frequency_response and unselect Default. c. Click OK. d. Click Apply.

b

b

c a d NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

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AP8-21



ID SEMINAR, PROB8 SOL 108 TIME 30 CEND TITLE= FREQUENCY RESPONSE DUE TO .1 DISPLACEMENT AT TIP SUBTITLE= DIRECT METHOD ECHO= UNSORTED SPC= 1 SET 111= 11, 33, 55 DISPLACEMENT(PHASE, SORT2)= 111 SDISP(PHASE, SORT2)= ALL set 222 = 11 OLOAD= 222 SUBCASE 1 DLOAD= 500 FREQUENCY= 100 $ OUTPUT (XYPLOT) $ XTGRID= YES YTGRID= YES XBGRID= YES YBGRID= YES YTLOG= YES YBLOG= NO XTITLE= FREQUENCY (HZ) YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASE XYPLOT DISP RESPONSE / 11 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASE XYPLOT DISP RESPONSE / 33 (T3RM, T3IP) YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDE YBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASE


XYPLOT DISP RESPONSE / 55 (T3RM, T3IP) $ BEGIN BULK $ $ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $ INCLUDE ’plate.bdf’ PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $ $ SPECIFY STRUCTURAL DAMPING $ PARAM, G, 0.06 $ $ APPLY UNIT DISPLACEMENT AT TIP POINT $ CMASS2, 5000, 1.0E+5, 11, 3 $ RLOAD2, 500, 600, , ,310 $ TABLED4, 310, 0., 1., 0., 10000., ,0., 0., -39.4784, ENDT $ DAREA, 600, 11, 3, 25.8799 $ $ SPECIFY FREQUENCY STEPS $ FREQ1, 100, 20., 20., 49 $ ENDDATA

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Windows Users:




AP8-23


Unix Users:




AP8-24


When the run is completed, use the plotps utility to create a postscript file, prob8.ps, from the binary plot file prob8.plt. The displacement response plots for Grids 11, 33 and 55 are shown at the end of this exercise.

Edit the prob8.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.

While still editing prob8.f06, search for the word X Y – O U T P U T S U M M A R Y (spaces are necessary) Displacement at Grid 11 Frequency (X)

Displacement (Y)

140

=

___________

380

=

___________


AP8-25

Step 8: Review F06 File (cont.) Displacement at Grid 33 Frequency (X)

Displacement (Y)

140

=

___________

600

=

___________


Displacement (Y)

140

=

___________

1000

=

___________


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AP8-27



a

c

d

b


AP8-28


Create a graph of Frequency vs. Displacement. a. Results: Create / Graph / Y vs X. b. Under Select Result case(s), click on frequency_response, 0 of 50 subcases. c. Select All as the Filter Method. d. Click Filter. e. Click Apply. f. Click Close.

a

b c

d

e


f

AP8-29


Create a graph of Frequency vs. Displacement (cont.). a. Select Displacement, Translational for the Select Y Result field. b. Select Z Component as the Quantity. c. Click on the Plot Options icon. d. Change Complex No. as to Magnitude. e. Click on Target Entities. f. Click in the Select Nodes box and select the lower right node (Node 11). g. Click Apply.

e

c

f

a d b g


AP8-30




AP8-31


Create a graph of Frequency vs. Displacement (cont.). a. Click Plot Options. b. Change Complex No. as to Phase. c. Click Apply.

a

Repeat the previous steps to plot nodes 33 and 55.

b

c NAS102, Appendix 8, January 2004 Copyright© 2004 MSC.Software Corporation

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AP8-33




AP8-34




AP8-35




AP8-36




AP8-37


AP8-38

NAS102 Dynamic Exercise

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