nas102 dynamic exercise

MSC.Software Corporation2 MacArthur Place

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MSC.Nastran Dynamic Analysis

March 2004

NAS102 Workbook

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 Plate2. Modal Analysis of a Flat Plate using Static Reduction

3. Direct Transient Response Analysis4. Modal Transient Response Analysis5. Direct Frequency Response Analysis6. Modal Frequency Response Analysis6a. Modal Frequency Response Analysis7a. Direct Transient Response with Base Excitation8a. Enforced Motion with Direct Frequency Response9a. Response Spectra9b. Response Spectra (cont.)10. Random Analysis11. Random Analysis12. Complex Modes of a Pile Driver13. Nolins in Linear Transient14a. Modal Analysis of a Beam14b. Normal Modes with Differential Stiffness15. Weight Minimization of a Three Bar Truss

Appendix Title1a. Modal Analysis of a Beam (SI Units)1b. Normal Modes with Differential Stiffness (SI Units)1c. Normal Modes with Differential Stiffness, using STATSUB7. Direct Transient Response with Base Excitation8. Enforced Motion with Direct Frequency Response

WS1-1NAS102, Workshop 1, January 2004Copyright© 2004 MSC.Software Corporation

WORKSHOP 1

MODAL ANALYSIS OF A FLAT PLATE


ObjectivesProduce 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.

Workshop 1 – Modal Analysis of a Flat Plate


a

b

Problem DescriptionFor 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.


Figure 1.1 - Grid Coordinates and Element Connectivities


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


Figure 1.2 Loads and Boundary Conditions


Natural Frequency: Hertz

Where i = 1,2,3, …j = 1,2,3, …

fijλ ij

2

2πa2------------ Eh3

12γ 1 ν2–( )

----------------------------1 2⁄

=



Description: Clamped-Free-Free-Free

a = length of plateb = width of plateh = thickness of platei = number of half-waves in mode shape along horizontal axisj = number of half-waves in mode shape along vertical axisC = clamped edgeE = modulus of elasticityF = free edgeS = simply supported edgeγ = mass per unit area of plate (μh for a plate material with density μ )υ = Poisson ratio



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)

2/3 3.502 6.406 14.54 22.04 26.07 31.62

(11) (12) (13) (21) (22) (14)

1.0 3.492 8.525 21.43 27.33 31.11 54.44

(11) (12) (21) (13) (22) (23)

1.5 3.477 11.68 21.62 39.49 53.88 61.99

(11) (12) (21) (22) (13) (31)

2.5 3.456 17.99 21.56 57.46 60.58 106.5

(11) (12) (21) (22) (31) (32)

λij2 and (ij)

υ = 0.3

Mode Sequence



MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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).PARAM, WTMASS, 0.00259PARAM, 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.



ID SEMINAR, PROB1______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________CEND________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________BEGIN BULK



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA




MSC.Patran Users1. 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.

MSC.Nastran Users should go to Step 9MSC.Nastran Users should go to Step 9


Step 1. Create a Database

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.

a

b

e

d

c g

f


Step 2. Create a Surface

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

d

c

b


Step 3. Create Finite Element Mesh

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

db

c

e


Step 3. Create Finite Element Mesh

Mesh the surface. a. Elements: Create / Mesh

/ Surface.b. Screen pick the surfacec. Click Apply.

a

c

b


Step 4. Create Material Properties

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.

a

d

b

c

e

f

g

h


Step 5. Create 2D Shell Properties

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.

a

d

b

c

e

f

a

g


a. Click in Select Members box.

b. Screen pick the surface.c. Click Add.d. Click Apply.

a

c

d

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

b


b

a

c

Step 6. Create Boundary Conditions

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

f

a


de

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

f

ac

Step 6. Create Boundary Conditions (cont.)

g


b

a

c

Step 7. Create a Model File

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.

a


b

a

c

Step 8. Create the Input File

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.

d

e


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.

g

d

f

e

Step 8. Create the Input File (cont.)

h

c

b

a


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.

c

b

f


a

d

e


b

a

c

a. Select SPCFORCES(SORT1,REAL)=All FEM.

b. Click Delete.c. Click OK.d. Click Apply.e. Click Cancel.f. Click Apply.

e fd




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.


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

ID SEMINAR, PROB1SOL 103TIME 600CENDTITLE = NORMAL MODES EXAMPLEECHO = UNSORTEDSUBCASE 1

SUBTITLE= USING LANCZOSMETHOD = 1SPC = 1VECTOR=ALL

BEGIN BULKPARAM COUPMASS 1PARAM WTMASS .00259EIGRL 1 5 PSHELL 1 1 .1 1 1CQUAD4 1 1 1 2 13 12=,*1,=,*1,*1,*1,*1=8CQUAD4 11 1 12 13 24 23=,*1,=,*1,*1,*1,*1=8CQUAD4 21 1 23 24 35 34=,*1,=,*1,*1,*1,*1=8CQUAD4 31 1 34 35 46 45=,*1,=,*1,*1,*1,*1=8

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:

MAT1 1 3.+7 .3 .282GRID 1 0. 0. 0.=,*1,=,*0.5,===9GRID 12 0. .5 0.=,*1,=,*0.5,===9GRID 23 0. 1. 0.=,*1,=,*0.5,===9GRID 34 0. 1.5 0.=,*1,=,*0.5,===9GRID 45 0. 2. 0.=,*1,=,*0.5,===9SPC1 1 12345 1 12 23 34 45ENDDATA


GRID 1 0. 0. 0.=,*1,=,*0.5,===9GRID 12 0. .5 0.=,*1,=,*0.5,===9GRID 23 0. 1. 0.=,*1,=,*0.5,===9GRID 34 0. 1.5 0.=,*1,=,*0.5,===9GRID 45 0. 2. 0.=,*1,=,*0.5,===9PSHELL 1 1 .1 1 1CQUAD4 1 1 1 2 13 12=,*1,=,*1,*1,*1,*1=8CQUAD4 11 1 12 13 24 23=,*1,=,*1,*1,*1,*1=8CQUAD4 21 1 23 24 35 34=,*1,=,*1,*1,*1,*1=8CQUAD4 31 1 34 35 46 45=,*1,=,*1,*1,*1,*1=8MAT1 1 3.+7 .3 .282SPC1 1 12345 1 12 23 34 45

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:

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


Step 10: Submitting the Input File for Analysis

Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select prob1.bdf or prob1.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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.

Unix Users:


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


Step 11: Review F06 File (cont.)

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

MSC.Nastran Users have finished this workshop.MSC.Nastran Users have finished this workshop.

MSC.Patran Users should proceed to the next step.MSC.Patran Users should proceed to the next step.


Step 12. Attach the XDB

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

b

a

e

f g

d

c


Step 13. View Results

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.

a

b

c

d


WORKSHOP 2

MODAL ANALYSIS OF A FLAT PLATE USING STATIC REDUCTION


ObjectivesReduce 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.

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


Problem DescriptionFor 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.

Figure 2.1 – Grid Coordinates and Element Connectivities


a

b


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



MSC.Nastran Users – Generate a MSC.Nastran input1. 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, 0.00259PARAM, 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.




3055790

3055790




1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA


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


MSC.Patran Users1. Create a new database.2. Import the input file.3. Add pre-defined constraints.4. Create the new analysis deck.5. Submit the input file for analysis.6. Review the F06 file.7. Attach the XDB.8. View the Results.


Step 1: Create New Database

Create a new database called prob2.db.




the Analysis Code.f. Select Structural as

the Analysis Type. g. Click OK.

a

b c

d

e

f

g


Step 2: Import the Input File

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.

a

c

d

e

e

fg

h

b


Step 3: Add the Pre-Defined Constraints

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.

a

b

c

e d


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

b

c

e

d

f


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

b

c

e d


a. Click on Direct Text Input…b. In the Bulk Data Section,

type in the following:

ASET1,345,3,5,7,9,11ASET1,345,25,27,29,31,33ASET1,345,47,49,51,53,55

c. Click OK.


a

b

c



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.

a

b

c

d

e

f

g



a. Click on Output Requests…

b. Under Output Requests, highlightSPCFORCES(SORT1,REAL)=ALL FEM

c. Click on Delete.d. Click OK.e. Click Apply.f. Click Cancel.g. Click Apply.

a

e fd

b

c

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.


Step 5: Review Input File for MSC.Nastran Users

ID SEMINAR, PROB2SOL 103TIME 10CENDTITLE = REDUCTION PROCEDURES, NORMAL MODES EXAMPLESUBTITLE = USING STATIC REDUCTIONECHO = UNSORTEDSUBCASE 1

SUBTITLE=USING LANCZOSMETHOD = 1SPC = 1VECTOR=ALL

BEGIN BULKEIGR,1,AGIV,,,,5PARAM, COUPMASS, 1PARAM, WTMASS, 0.00259INCLUDE ’plate.bdf’$$ SELECT A-SET, STATIC REDUCTION IS DONE AUTOMATICALLY$ASET1,345,3,5,7,9,11ASET1,345,25,27,29,31,33ASET1,345,47,49,51,53,55ENDDATA





Windows Users:




Unix Users:




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


Step 8: Attach XDB

Proceed with the Reverse Translation process, that is attaching the prob.xdbresults 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 labelsg. Select Iso 3 view. b

a

c

d

e

f g


Step 9: View the Results

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.

a

b

c

d


WORKSHOP 3

DIRECT TRANSIENT RESPONSE ANALYSIS


ObjectivesDefine 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.

Workshop 3 – Direct Transient Response Analysis


Problem DescriptionUsing the direct method, determine the transient response of the flat rectangular plate, created in Workshop 1, under time-varying excitation. This example structure shall be excited by 1psi 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.





1 psi over the total surface

50.00


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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-of-phase).

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.PARAM, G, 0.06PARAM, 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Import an existing model.3. Create a load case.4. Create time dependent fields.5. Create load/boundary conditions.6. Create a MSC.Nastran input file.7. Review the MSC.Nastran input file.8. Submit the input file to MSC.Nastran for analysis.9. Review the .F06 file.10. Attach the XDB file.11. View results.

MSC.Nastran Users should go to step 7MSC.Nastran Users should go to step 7



Step 1. Create New Database







a

b

e

d

cg

f


Step 2. Import Existing Model

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.

b

c

ac

d

e

d


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

b

c

d

e

f

g


Step 4. Create Time Dependent Fields

Create a time-dependent non-spatial field.

a. Fields: Create / Non Spatial / Tabular Input

b. Enter time_dependent_pressurefor the Field Name.

c. Click [Options…].d. Enter 21 for Maximum Value of t.e. Click OK.

a

b

ce

d


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

f

gi j



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

m

l



Create another time-dependent field for the transient response of the nodal force.


b. Enter time_dependent_force for the Field Name.


a

b

ce

d






h

fg

i j





k

m

l


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_pressure for the Time/Freq. Dependent Field.

f. Click OK.g. Click on Select

Application Region.h. Choose FEMi. Select all the

elements for the application region.

j. Click Add, and click OK.

k. Click Apply.

a

b

c

d

e

f

g

h

k

j

i

j


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_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 Node 11 on

the bottom right corner of the plate.

i. Click Add, and click OK.

j. Click Apply.

a

b

c

d

e

f

g

h

i

j

i

d



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.

c

d

e

a b

f


b

a

c

Step 6. Create Input File





d

e


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 Wt-

Mass Conversion.

f. Enter 0.06 for Struct. Damping Coefficient and 1571 for W3, Damping Factor.

g. Click OK.h. Click OK.

a

b

cd

e

f

g

h




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.

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

f. Click OK.g. Click OK.

ac

b

d

e

f

g




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(SORT2,REAL)=All FEM and select By Freq/Time under Options: Sorting.

e. Click OK.f. Click Apply.g. Click Cancel.

a

b

cd

e

c

d

f g




a. Click on Subcase Select.b. Select

transient_response and unselect Default.

c. Click OK.d. Click Apply.

a

b

c

d

b



D SEMINAR, PROB3SOL 109TIME 30CENDTITLE= TRANSIENT RESPONSE WITH TIME DEPENDENT PRESSURE AND POINT LOADSSUBTITLE= USE THE DIRECT METHOD ECHO= PUNCHSPC= 1SET 1= 11, 33, 55DISPLACEMENT= 1SUBCASE 1DLOAD= 700 $ SELECT TEMPORAL COMPONENT OF TRANSIENT LOADINGLOADSET= 100 $ SELECT SPACIAL DISTRIBUTION OF TRANSIENT LOADINGTSTEP= 100 $ SELECT INTEGRATION TIME STEPS$OUTPUT (XYPLOT)XGRID=YESYGRID=YESXTITLE= TIME (SEC)YTITLE= DISPLACEMENT RESPONSE AT LOADED CORNERXYPLOT DISP RESPONSE / 11 (T3)YTITLE= DISPLACEMENT RESPONSE AT CENTER TIPXYPLOT DISP RESPONSE / 33 (T3)YTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNERXYPLOT DISP RESPONSE / 55 (T3)$BEGIN BULKPARAM, COUPMASS, 1PARAM, WTMASS, 0.00259$$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE$


INCLUDE ’plate.bdf’$$ SPECIFY STRUCTURAL DAMPING$ 3 PERCENT AT 250 HZ. = 1571 RAD/SEC.$PARAM, G, 0.06PARAM, W3, 1571.$ $ APPLY UNIT PRESSURE LOAD TO PLATE$LSEQ, 100, 300, 400$PLOAD2, 400, 1., 1, THRU, 40$$ 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


Step 8: Submit Input File for Analysis


Windows Users:


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


Unix Users:



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 = ___________




Time T3

.0024 = ___________

.0052 = ___________

.02 = ___________


Time T3

.0024 = ___________

.0052 = ___________

.02 = ___________


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

b

c

d

e



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

e f


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.

b

a

c

d

e

f

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



Displacement Response at Node 11

Node 55 Displacement


WORKSHOP 4

MODAL TRANSIENT RESPONSE ANALYSIS



Workshop 4 – Modal Transient Response Analysis


Problem DescriptionUsing the modal method, determine the transient response of the flat rectangular plate, created in Workshop 1, under time-varying excitation. This example structure shall be excited by 1psi 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.






25.00



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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA










a

b

e

d

cg

f









b

c

ac

d

e

d








a

b

c

d

e

f

g





b. Enter time_dependent_pressurefor the Field Name.


a

b

ce

d






h

f

gi j





k

m

l



Create another time-dependent field for the transient response of the nodal force.


b. Enter time_dependent_force for the Field Name.


a

b

ce

d






h

f

gi j





k

m

l



Create the time-dependent pressure load.





e. Enter -1 for Top Surf Pressure, and select time_dependent_pressure for the Time/Freq. Dependent Field.


Application Region.h. Choose FEMi. Select all the

elements for the application region.

j. Click Add, and click OK.

k. Click Apply.

a

b

c

d

e

f

g

h

k

j

i

j



Create the time-dependent force load.




d. Enter <0,0,25> for Force, and select time_dependent_force for the Time/Freq. Dependent Field.



Filter to FEM.h. Select Node 11 on

the bottom right corner of the plate.


j. Click Apply.

a

b

c

d

e

f

g

h

i

j

i

d





Load/BC Sets, select Displ_spc1.1, Force_force, and Press_pressure.


f. Click Apply.

c

d

e

a b

f


b

a

c






d

e






to Modal.d. Click on Solution

Parameters.e. Change the Mass

Calculation to Coupled.f. Enter 0.00259 for Wt-

Mass Conversion.

a

b

cd

e

f

i




a. Click on EigenvalueExtraction.

b. Set the Number of Desired Roots to 5.

c. Click OK.d. Click OK.e. Click OK.

b

c

d

a

e








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

f. Click OK.

a

c

b

d

e

f




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.

ab

d

c

e

f









a

b

cd

e

c

d

f g







a

b

c

d

b



ID SEMINAR, PROB4SOL 112TIME 30CENDTITLE = TRANSIENT RESPONSE WITH TIME DEPENDENT PRESSURE AND POINT LOADSSUBTITLE = USE THE MODAL METHOD ECHO = UNSORTEDSPC = 1SET 111 = 11, 33, 55DISPLACEMENT(SORT2) = 111SDAMPING = 100SUBCASE 1METHOD = 100DLOAD = 700LOADSET = 100TSTEP = 100$OUTPUT (XYPLOT)XGRID=YESYGRID=YESXTITLE= TIME (SEC)YTITLE= DISPLACEMENT RESPONSE AT LOADED CORNERXYPLOT DISP RESPONSE / 11 (T3)YTITLE= DISPLACEMENT RESPONSE AT TIP CENTERXYPLOT DISP RESPONSE / 33 (T3)YTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNERXYPLOT DISP RESPONSE / 55 (T3)$BEGIN BULKPARAM, COUPMASS, 1PARAM, 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




Windows Users:




Unix Users:



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




Time T3

.0064 = ___________

.0092 = ___________

.02 = ___________




Time T3

.0068 = ___________

.0092 = ___________

.02 = ___________


Time T3

.0068 = ___________

.0092 = ___________

.02 = ___________







a

b

c

d

e








a

b

c

d

e f









f. Click Apply.

b

a

c

d

e

f

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



Displacement Response at Loaded Corner (Node 11)



Displacement Response at Tip Center (Node 33)



Displacement Response at Opposite Corner (Node 55)


WORKSHOP 5

DIRECT FREQUENCY RESPONSE ANALYSIS


ObjectivesDefine 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.

Workshop 5 – Direct Frequency Response Analysis


Problem DescriptionUsing the direct method, determine the frequency response of the flat rectangular plate, created in Workshop 1, under time-varying 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




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

PARAM, G, 0.066. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA










a

b

e

d

cg

f









b

c

ac

d

e

d



Create a frequency-dependent load case called frequency_response.

a. Load Cases: Create.b. Enter frequency_response




a

b

c

d

e

fg


Step 4. Create Frequency Dependent Fields

Create a frequency-dependent non-spatial field.a. Fields: Create / Non Spatial / Tabular Inputb. 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

c

e

df


Step 4. Create Frequency Dependent Fields (cont.)

a

b

d

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



Create the frequency-dependent unit force.




d. Enter <0 0 1> for Force, and select frequency_dependent_load for the Time/Freq. Dependent Field.


Application Region.g. Change the

Geometry Filter to FEM.

h. Select Node 11 on the bottom right corner of the plate.


j. Click Apply.

a

b

c

d

e

f

g

h

ij

i

d





Load/BC Sets, select Displ_spc1.1 and Force_force.


f. Click Apply.

c

d

e

a b

f


b

a

c






d

e




a. Click on Solution Type. b. Select Frequency





Mass Conversion.

g. Enter 0.06 for Struct. Damping Coefficient.

h. Click OK.i. Click OK. a

b

cd

e

f

g

hi





frequency_response from the Available Subcases field.


d. Click on DEFINE FREQUENCIES button.

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


a

c

b

d

e

f

g









a

b

cd

e

c

d

f g




a. Click on Subcase Select.b. Select frequency_response

and unselect Default.c. Click OK.d. Click Apply.

a

b

c

d

b



ID SEMINAR, PROB5SOL 108TIME 30CENDTITLE = FREQUENCY RESPONSE DUE TO UNIT FORCE AT TIPECHO = UNSORTEDSPC = 1SET 111 = 11, 33, 55DISPLACEMENT(SORT2, PHASE) = 111SUBCASE 1DLOAD = 500FREQUENCY = 100$OUTPUT (XYPLOT)$XTGRID= YESYTGRID= YESXBGRID= YESYBGRID= YESYTLOG= YESYBLOG= NOXTITLE= FREQUENCY (HZ)YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASEXYPLOT DISP RESPONSE / 11 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASEXYPLOT DISP RESPONSE / 33 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASEXYPLOT DISP RESPONSE / 55 (T3RM, T3IP)$


BEGIN BULKPARAM, COUPMASS, 1PARAM, 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




Windows Users:




Unix Users:


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)


Frequency (X) Displacement (Y)

140 = ___________

380 = ___________


Step 9: Review Results (cont.)



140 = ___________

600 = ___________



140 = ___________

1000 = ___________





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







a

b

c

d

e



Create a graph of Frequency vs. Displacement.


b. Under Select Result case(s), click on frequency_response, 0 of 50 subcases.



a

b

c

d

e f



Create a graph of Frequency vs. Displacement (cont.).






b

a

c

d

e

f




a. Click on the Plot Options icon.

b. Change Complex No. as to Magnitude.

c. Click Apply.

b

a

c





a. Change Complex No. as to Phase.

b. Click Apply.

a

b

Repeat the previous steps to plot nodes 33 and 55.

Phase Angle at Node 11


WORKSHOP 6

MODAL FREQUENCY RESPONSE ANALYSIS


ObjectivesDefine 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.

Workshop 6 – Modal Frequency Response Analysis



Problem DescriptionUsing 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


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA




MSC.Patran Users1. Create a new database.2. Import the input file.3. Create a frequency dependent load case for the frequency response.4. Create a frequency dependent field for the frequency response.5. Create a frequency dependent unit force.6. Create forces.7. Create an MSC.Nastran input file.8. Review the MSC.Nastran input file.9. Submit the model to MSC.Nastran for analysis.10. Review the .F06 file.11. Attach the XDB file.12. Plot the results.










a

b

e

d

c g

f


Step 2. Import the Input File

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.

a

c

b

d

e

fg

h


Step 3. Create a Frequency Dependent Load Case

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 Dependentfor Load Case Type.

d. Click on Assign/Prioritize Loads/BCs.

e. Click on Displ_spc1.1under Select Individual Loads/BCs.

f. Click OK.g. Click Apply.

a

d

b

c

e

fg


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_load 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. Click OK.j. Click Apply.

a

c

b

g

f

e

dFreq(f) Value

10. 1.0

1000. 1.0

h

ij


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

d

b

c

e f

g

h

i

j

k

l

m

f


Step 6. Create Forces

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

<F1 F2 F3>.e. Select

frequency_dependent_load from the Time/Freq. Dependence box.


Application Region…

d

b

c

e

f

a

g


Step 6. Create Forces (cont.)

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.

d

b

c

a

e

f g

b


Plot the markers of the forcescreated.a. Action: Plot Markersb. 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 Labelsicon on the toolbar.

a

c

b

Step 6: Create Forces (cont.)

e

d


b


Create an input file for analysis:a. Analysis: Analyze/Entire

Model/Analysis Deck.b. Enter prob6 for the Job


Parameters…d. Select XDB and Print for Data

Output.e. Click OK.f. Click on Solution Type…

d

e

f

a

c


e

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.

b

fa

c


g

d

i h

d


b

a

ca. Click on Subcases…b. Action: Createc. Select frequency_response

from Available Subcases.d. Click Subcase Parameters…e. Click on DEFINE

FREQUENCIES…f. Click Add Row.g. Enter:

h. Click OK.


Incr. Type

Start Freq.

End Freq.

No.Incr.

Cluster/Spread

1 Linear 20 1000 49 Not Used

2 Linear 20 1000 5 Not Used d

e

f

g

h


ba

c


a. Select Crit. Damp. (CRIT)from Modal Damping.

b. Click on DEFINE MODAL DAMPING…

c. Click Add Row.d. Enter:

e. Click OK.f. Click OK.

d

e

f

Frequency Value

1 0 .03

2 10 .03


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.

dfe


c

b

a


a. Click Subcases Select…

b. Click on Default under Subases Selected to de-select it.

c. Click on frequency_responseunder Subcases for Solution Sequence.

d. Click OK.e. Click Apply.

c

b


a

de


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 8 9 1

Insert the identification number of the DPHASE entry in the 5th

field. The revised RLOAD1 card should look as follows:

RLOAD1 8 9 92 1

Also, insert the necessary DPHASE card:

DPHASE 92 11 3 -45.

Step 8. Edit Input File for MSC.Nastran Users



Step 9. Review Input File for MSC.Nastran Users

ID SEMINAR, PROB6SOL 111TIME 30CENDTITLE = FREQUENCY RESPONSE WITH PRESSURE AND POINT LOADSSUBTITLE = USING THE MODAL METHOD WITH LANCZOSECHO = UNSORTEDSEALL = ALLSPC = 1SET 111 = 11, 33, 55DISPLACEMENT(PHASE, PLOT) = 111METHOD = 100FREQUENCY = 100SDAMPING = 100SUBCASE 1DLOAD = 100LOADSET = 100$OUTPUT (XYPLOT)$XTGRID= YESYTGRID= YESXBGRID= YESYBGRID= YESYTLOG= YESYBLOG= NOXTITLE= FREQUENCY (HZ)YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASEXYPLOT DISP RESPONSE / 11 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASE



$ 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$FREQ1, 100, 20., 20., 49FREQ4, 100, 20., 1000., .03, 5$ENDDATA

XYPLOT DISP RESPONSE / 33 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASEXYPLOT DISP RESPONSE / 55 (T3RM, T3IP)$BEGIN BULK$$ PARAMETERS FOR POST-PROCESSINGPARAM,COUPMASS,1PARAM,WTMASS,0.00259$$ 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$


Step 10. Submitting the Input File for Analysis


Windows Users:




Unix Users:


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.


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).



140 = ______________

440 = ______________

Displacement at Grid 33Frequency (X) Displacement (Y)

140 = ______________

660 = ______________


140 = ______________

1000 = ______________


Step 12. Compare the Results

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





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.


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.

a

b

a

e

f g

d

c


Step 14. Plot the Results

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 Xb. Select

Frequency_response, 0 of 54 from Select Results Case.



a

b

c

d

e 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 Display

Attributes icon.

Step 14. Plot the Results (cont.)

f

g

a

bcd

e


a. Select Log for Y Axis Scale.b. Click on the Target Entities

icon.c. Select Node 11 under Select

Nodes.d. Click Apply.


a

d

c

b

c



Displacement Response at Loaded Corner (Node 11)



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

b

a



Displacement Response at Tip Center (Node 33)



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

b

a



Displacement Response at Opposite Corner (Node 55)

WS6A-1

WORKSHOP 6A

MODAL FREQUENCY RESPONSE ANALYSIS

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


MODAL FREQUENCY RESPONSE

Problem DescriptionUsing 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.



Problem Description (cont.)Below is a finite element representation of the flat plate. It also contains the loads and boundary constraints.

1.0

0.1 psi. over the total surface



Suggested Exercise Steps1. Import the input file.2. Create a non-spatial field for the pressure load and the force load.3. Create a time dependent load case.4. Create the time dependent force load.5. Create the time dependent pressure load.6. Submit the model to MSC.Nastran for analysis.7. Attach the .XDB results file.8. Post Process results – create X vs Y graph of displacements.


CREATE NEW DATABASE

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


a

b c

d

e

f

g


Step 1. File / Import



b. Enter prob6A for Job Name.



Labels icon.

a

c

b

d

e

fg

h


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

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.

a

b

c

d

e

f

g


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

Create a Non Spatial field for the force load.


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

b

c

d

e

f

h

g


Step 3. Load Cases: Create

Create a Time Dependent load case.a. Load cases: Createb. 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. b

c

d

e

fg

a


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

Create the time dependent Force load.


b. Enter Force for the New Set Name.


d. Enter <0,0,1> for Force, and select force for the Time/Freq. Dependent Field.



Filter to FEM.h. Select the node on the

bottom right corner.i. Click Add, and click OK.j. Click Apply.

a

b

c

d

e

f

g

h

j

i

i


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

Create the time dependent Pressure load.





e. Enter -0.1 for Top Surf Pressure, and select pressure for the Time/Freq. Dependent Field.


Application Region.h. Select all the elements

for the application region.i. Click Add, and click OK.j. Click Apply.

a

b

c

d

e

f

g

h

i

j

i


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

b

c

de

f

h i

g


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

Submit the model for analysis (cont.).


modal_freq_response from the Available Subcases field.


d. Click on DEFINE FREQUEYNCIES button.

e. Use the values in the table.

f. Click OK.

a

b

c

d

e

f




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

b

c

d

e




a. Click on Subcase Select.

b. Select modal_freq_response and unselect Default.


a

b

c

d


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



b. Click on Select Result File.

c. Select ws6.xdb.d. Click OK.e. Click Apply.

a

b

c

e

d


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



b. Click on SC1:MODAL_FREQ_RESPONSE.

c. Select Global Variable as the Filter Method.


a

b

c

d

e f


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






e. Select the node where force is applied.

f. Click Apply.

b

a

c

d

e

f




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.

b

ac

d

e



Displacement Magnitude vs. Frequency Plot



Create a X-Y graph of phaseresults.

a. Change Complex No. as from Magnitude to Phase.

b. Change Y Axis Scale from Log to Linear.

c. Click Apply.

a

b

a



a

b

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.

WS7a-1NAS102, Workshop 7a, January 2004Copyright© 2004 MSC.Software Corporation

WORKSHOP 7a

DIRECT TRANSIENT RESPONSE WITH BASE EXCITATION



Workshop 7a – Direct Transient Response With Base Excitation


Problem DescriptionUsing the direct method, determine the transient response to a unit acceleration sine pulse of 250Hz applied at the base in thez 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




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.PARAM, G, 0.06PARAM, 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.



ID SEMINAR, PROB7A______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________CEND________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________BEGIN BULK



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Import an existing model.3. Create a load case.4. Create a RBE2.5. Create time dependent fields.6. Create load/boundary conditions.7. Create a MSC.Nastran input file.8. Review the MSC.Nastran input file.9. Submit the input file to MSC.Nastran for analysis.10. Review the .F06 file.11. Attach the XDB file.12. View results.





Create a new database named prob7a.db.

a. File / New.b. Enter prob7a as the file





a

b

e

d

c g

f








e. Click Show Labels.f. Switch to Iso 3 View.

b

c

ac

d

e f

d








a

b

c

d

e

f

g


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

d

f

j

c

eg

h i





b. Enter time_dependent_acceleration for the Field Name.


a

b

ce

d






h

f

gi j





k

m

l



Create the time-dependent unit acceleration.

a. Loads/BCs: Create / Acceleration / Nodal.

b. Enter unit_acceleration for the New Set Name.


d. Enter <0, 0, 1.0> for Trans. Accel., and select time_dependent_acceleration for the Time/Freq. Dependent Field.


Application Region.g. Choose FEMh. Select the center

node on the left side of the plate (Node 23).


j. Click Apply.

a

b

c

d d

e

f

g

j

i

h

i



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

b

c

d

e

f

e


b

a

c



Model / Analysis Deck.b. Enter prob7a as the Job



d

e









Mass Conversion.

g. Enter 0.06 for Struct. Damping Coefficient and 1571 for W3, Damping Factor.

h. Click OK.i. Click OK.

a

b

cd

e

f

g

i

h








e. Change No. of Time Steps to 200, and Delta-T to 0.0002.


ac

b

d

e

f

g





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.

a

b

f

c

e

b

d







a

b

c

d

b


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.




ID SEMINAR, PROB7ASOL 109TIME 30CENDTITLE = TRANSIENT RESPONSE WITH BASE EXCITATIONSUBTITLE = USING DIRECT TRANSIENT METHOD, NO REDUCTIONECHO = UNSORTEDSPC = 200SET 111 = 23, 33DISPLACEMENT (SORT2) = 111VELOCITY (SORT2) = 111ACCELERATION (SORT2) = 111SUBCASE 1DLOAD = 500TSTEP = 100$OUTPUT (XYPLOT)XGRID=YESYGRID=YESXTITLE= TIME (SEC)YTITLE= BASE ACCELERATIONXYPLOT ACCELERATION RESPONSE / 23 (T3)YTITLE= BASE DISPLACEMENT XYPLOT DISP RESPONSE / 23 (T3)YTITLE= TIP CENTER DISPLACEMENT RESPONSEXYPLOT DISP RESPONSE / 33 (T3)$BEGIN BULK$$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE$

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:

INCLUDE ’plate.bdf’PARAM, COUPMASS, 1PARAM, WTMASS, 0.00259$$ SPECIFY STRUCTURAL DAMPING$PARAM, G, 0.06PARAM, W3, 1571.$$ APPLY EDGE CONSTRAINTS$SPC1, 200, 12456, 1, 12, 23, 34, 45SPCI, 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



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select prob7a.bdf or prob7a.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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 pscommand. 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.

Unix Users:



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)


Time T3

0 = ___________

.02 = ___________

.04 = ___________




Time 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 = ___________



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 = ___________




Time T3

0 = ___________

.02 = ___________

.04 = ___________






c. Select prob7a.xdb.d. Click OK.e. Click Apply.

a

b

c

d

e








a

b

c

d

e f



Create a X-Y graph of displacement results (cont.).a. Select Displacement,

Translational for the Select Y Result field.




e. Select the center node on the left edge of the plate (Node 23).

f. Click Apply.

b

a

c

d

e

f



Base Displacement at Node 23



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.

b

a

Tip Displacement at Node 33



Create a X-Y graph of displacement results (cont.).a. Click Select Results.b. Under Select Y Result,

select Velocities, Translational.


d. Select the center node on the left edge of the plate (Node 23).

e. Click Apply.b

a c

d

e



Base Velocity at Node 23





b. Click Apply.

b

a

Tip Velocity at Node 33




select Accelerations, Translational.

c. Click Target Entities.d. Select the center node

on the left edge of the plate (Node 23).

e. Click Apply.

b

a c

d

e



Base Acceleration at Node 23





b. Click Apply.

b

a

Tip Acceleration at Node 33


WORKSHOP 8a

ENFORCED MOTION WITH DIRECT FREQUENCY RESPONSE


ObjectivesDefine 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.

Workshop 8 – Enforced Motion with Direct Frequency Response



Problem DescriptionUsing 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



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.

PARAM, G, 0.066. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Import the input file.3. Create a frequency dependent load case.4. Create a frequency dependent field for the frequency dependent load.5. Create a frequency dependent unit force.6. Create an MSC.Nastran input file.7. Submit the model to MSC.Nastran for analysis.8. Review the .F06 file.9. Attach the XDB file.10. Plot the results.

MSC.Nastran Users should go to Step 7.MSC.Nastran Users should go to Step 7.










a

b

e

d

cg

f


Step 2. Import the Input File



b. Enter prob8a for Job Name.



Labels icon.

a

c

b

d

e

fg

h


Step 3. Create a Frequency Dependent Load Case

a. Load Cases: Create.b. Enter

frequency_response for Load Case Name.

c. Select Time Dependentfor Load Case Type.

d. Click on Assign/Prioritize Loads/BCs.

e. Click on Displ_spc1.1under Select Individual Loads/BCs.


a

d

b

c

e

fg


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_load 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:


a

c

b

g

f

e

dFreq(f) Value

10. 1.0

1000. 1.0

j

h

i


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_loadfrom 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.

ad

b

c

e

f

g

h

i

j

k

l

e


b



Model/Analysis Deck.b. Enter prob8a for the Job


Parameters…d. Select XDB and Print for Data

Output.e. Click OK.f. Click on Solution Type…

d

e

f

a

c


h

e

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…

b

d

a

c


g

d

f


b

a

c


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. = 20End Freq. = 1000No. Incr. = 49

f. Click OK.g. Click on Ouput Requests… d

e

f

g

a


b

a

c


a. Highlight SPCFORCES(SORT1,Real)=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_responseunder Subcases for Solution Sequence: 108.


h

g

f

i

j



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.


ID SEMINAR, PROB8SOL 108TIME 30CENDTITLE= FREQUENCY RESPONSE DUE TO .1 DISPLACEMENT AT TIPSUBTITLE= DIRECT METHODECHO= UNSORTEDSPC= 1SET 111= 11, 33, 55DISPLACEMENT(PHASE, SORT2)= 111SDISP(PHASE, SORT2)= ALLset 222 = 11OLOAD= 222SUBCASE 1DLOAD= 500FREQUENCY= 100$OUTPUT (XYPLOT)$$XTGRID= YESYTGRID= YESXBGRID= YESYBGRID= YESYTLOG= YESYBLOG= NOXTITLE= FREQUENCY (HZ)YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASEXYPLOT DISP RESPONSE / 11 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASEXYPLOT DISP RESPONSE / 33 (T3RM, T3IP)


YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASEXYPLOT DISP RESPONSE / 55 (T3RM, T3IP)$BEGIN BULK$$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE$INCLUDE ’plate.bdf’PARAM, COUPMASS, 1PARAM, WTMASS, 0.00259$$ 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





Windows Users:



Submit the input file to MSC.Nastran for analysisTo submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob8a.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 prob8a scr=yes. Monitor the run using the UNIX ps command.

Unix Users:



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.


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).



140 = ______________

380 = ______________


140 = ______________

600 = ______________


140 = ______________

1000 = ______________



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.


b. Click Select Results File.c. Select prob8a.xdb.d. Click OK.e. Click Apply.

a

b

a

e

d

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 Xb. Select

Frequency_response, 0 of 50 from Select Results Case.



a

b

c

d

e 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.


f

g

a

bcd

e

h

ih



The Displacement versus Frequency plot at Node 11 should resemble the graph below:



Next plot the Phase versus Frequency.

a. Click on the Plot Optionsicon.

b. Select Phase for Complex No. as.

c. Click Apply.

a

b

c



Repeat the above steps of plotting the XY plots for Nodes 33 and 55.


b. Select Magnitude for Complex No. as.

c. Click the Target Entities icon.d. Select Node 33.e. Click Apply.

a

b

c

d

d

e



Next plot the Phase versus Frequency for Node 33.



c. Click Apply.

a

b

c




b. Select Magnitude for Complex No. as.

c. Click the Target Entities icon.d. Select Node 55.e. Click Apply.

a

b

c

d

d

e



Finally, plot the Phase versus Frequency for Node 55.



c. Click Apply.

a

b

c


WORKSHOP 9a

Response Spectra

Response

Resonant Frequency (Hz)


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

Workshop 9a – Response Spectra


Model DescriptionDefine 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


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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.

PARAM, RESPECTRA, 07. Generate an input file and submit it to the MSC.Nastran solver for direct

transient analysis.8. Review the results.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



Step 1: Generate and Review Input File

ID SEMINAR, PROB9ASOL 109TIME 30CENDTITLE= TRANSIENT RESPONSESUBTITLE= USING DIRECT TRANSIENT METHOD LABEL= SHOCK SPECTRUM CALCULATIONECHO= UNSORTEDSPC= 100SET 111= 3000 DISPLACEMENT (SORT2)= 111 $ AT LEAST DISP AND VEL MUST APPEARVELOCITY (SORT2)= 111ACCELERATION= 111DLOAD= 500TSTEP= 100$OUTPUT (XYPLOT)$$ SHOCK RESPONSE IS ONLY AVAILABLE IN PLOT OR PUNCH OUTPUT. THEREFORE, $ THE ‘OUTPUT(XYPLOT)’ SECTION OF THE CASE CONTROL MUST BE USED.$XGRID=YESYGRID=YESXYPLOT ACCE / 3000(T1)XLOG= YESYLOG= YES$$ 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

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

$XTITLE= FREQUENCY (CYCLES/SEC)YTITLE= RELATIVE DISPLACEMENTXYPLOT DISP SPECTRAL 1 / 3000 (T1IP)YTITLE= RELATIVE VELOCITYXYPLOT VELOCITY SPECTRAL 1 / 3000 (T1IP)YTITLE= ABSOLUTE ACCELERATIONXYPLOT 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


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

$$ SPECIFY FREQUENCY AND DAMPING VALUES FOR$ THE SDOF OSCILLATORS AT GRID 3000$DTI, SPSEL, 0DTI, SPSEL, 1, 111, 222, 3000$ 1= SUBCASE... 111= DAMPING... 222= FREQUENCIES... 3000= GRID NUMBER$$ DAMPING INFORMATION FOR OSCILLATORS$FREQ, 111, 0., 0.02, 0.04$$ NATURAL FREQUENCIES OF OSCILLATORS$FREQ1, 222, 20., 20., 49$ENDDATA




Windows Users:



Submit the input file to MSC.Nastran for analysisTo submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob9a.bdf scr=yes. Monitor the run using the UNIX pscommand. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob9a scr=yes. Monitor the run using the UNIX ps command.

Unix Users:


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.



Step 3: View Results (cont.)

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

WS9b-1NAS102, Workshop 9b, January 2004Copyright© 2004 MSC.Software Corporation

WORKSHOP 9b

Response Spectra (cont.)

Response

Resonant Frequency (Hz)


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

Workshop 9b – Response Spectra (cont.)


Model DescriptionDefine 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


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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.

PARAM, SCRSPEC, 0PARAM, OPTION, SRSSPARAM, LFREQ, 0.1PARAM, HFREQ, 1000

11. Generate an input file and submit it to the MSC.Nastran solver (SOL 103).12. Review the results.



ID SEMINAR, PROB9B______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________CEND________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________BEGIN BULK



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA




ID SEMINAR, PROB9BSOL 103TIME 30CENDTITLE= RESPONSE SPECTRUM ANALYSISSUBTITLE= USING CALCULATED SHOCK RESPONSELABEL= SHOCK WILL BE INPUT IN Z DIRECTIONECHO= UNSORTEDSET 111= ALLDISPLACEMENT= 111SPC= 200SUBCASE 1METHOD= 100SDAMP= 200DLOAD= 500$BEGIN BULK$$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE$INCLUDE ’plate.bdf’PARAM,COUPMASS,1PARAM,WTMASS,0.00259$$ 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

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

$$ SUPPORT CARD TO IDENTIFY EXCITATION DOFS$SUPORT, 23, 3$$ 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, 0.1PARAM, HFREQ, 1000.$$ SPECIFICATION FOR SHOCK TABLES



$DTI, SPECSEL, 0DTI, 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. .576059100. .862049 120. 1.17619 140. 1.50169 160. 1.82018180. 2.11404 200. 2.36801 220. 2.56617 240. 2.70027260. 2.76275 280. 2.75073 300. 2.74632 320. 2.61887340. 2.4218 360. 2.39068 380. 2.24931 400. 2.02296420. 1.78538 440. 1.70355 460. 1.57056 480. 1.40493500. 1.22608 520. 1.20483 540. 1.17631 560. 1.14097580. 1.10048 600. 1.05582 620. 1.00818 640. .958761660. .908725 680. .859158 700. .827667 720. .782127740. .728996 760. .694088 780. .668602 800. .635044820. .598496 840. .571831 860. .563072 880. .550499900. .528854 920. .509281 940. .500534 960. .498016980. .488793 1000. .468321 ENDT

$ACCE 4 3000 3 52$ 2.0000000E-02TABLED1 3

20. .037708 40. .143365 60. .314936 80. .541342100. .80976 120. 1.10506 140. 1.40671 160. 1.69567180. 1.98167 200. 2.22217 220. 2.35249 240. 2.53055260. 2.56231 280. 2.55577 300. 2.58668 320. 2.45921340. 2.29411 360. 2.25956 380. 2.12901 400. 1.92605420. 1.68656 440. 1.61355 460. 1.4968 480. 1.35263500. 1.19796 520. 1.17707 540. 1.14947 560. 1.11613580. 1.07807 600. 1.03637 620. .992124 640. .946383660. .900171 680. .854434 700. .810016 720. .767647740. .727923 760. .691288 780. .658039 800. .628311



820. .602091 840. .579207 860. .559362 880. .542128900. .526973 920. .51329 940. .500403 960. .487602980. .474171 1000. .459408 ENDT

$ACCE 4 3000 3 103$ 4.0000000E-02TABLED1 4

20. .039336 40. .137673 60. .297382 80. .511244100. .764891 120. 1.04406 140. 1.31588 160. 1.58461180. 1.85678 200. 2.10175 220. 2.19165 240. 2.3921260. 2.39929 280. 2.42782 300. 2.44263 320. 2.317340. 2.17923 360. 2.14283 380. 2.0227 400. 1.8407420. 1.62279 440. 1.53417 460. 1.43168 480. 1.30597500. 1.17212 520. 1.15165 540. 1.12513 560. 1.09349

$580. 1.05768 600. 1.01868 620. .977462 640. .934986

660. .892143 680. .849752 700. .808538 720. .769114740. .731968 760. .69746 780. .665814 800. .637115820. .611319 840. .588261 860. .567655 880. .549125900. .532205 920. .516369 940. .501047 960. .485644980. .469568 1000. .452243 ENDT

$ENDDATA



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select prob9b.bdf or prob9b.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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 pscommand. 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.

Unix Users:



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.



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


WORKSHOP 10A

RANDOM ANALYSIS


ObjectivesDefine 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.

Workshop 10A – Random Analysis


Problem DescriptionFor the plate model, enforce a base motion in the z-direction described by the following power spectral density, (PSD).


Frequency G2/Hz

30 1

100 1

500 0.1

20 0.1

1000. 0.1

Autospectra of the Base Excitation


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.




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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



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

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


Step 1. Review the Input File for MSC.Nastran Users (cont.)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


YTTITLE= ACCEL RESPONSE AT OPPOSITE CORNER, MAGNITUDE

YBTITLE= ACCEL RESPONSE AT OPPOSITE CORNER, PHASE


$

$ 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


YTITLE= ACCEL P S D AT OPPOSITE CORNER


$

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

$



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select prob10A.bdf or prob10A.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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.

Unix Users:



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.


Step 4. View the Plots


Step 4. View the Plots (cont.)

WS10B-1

WORKSHOP 10B

RANDOM ANALYSIS USING MSC.RANDOM

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


Problem DescriptionThis workshop carries out a Random Response Analysis of the flatplate 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.

RANDOM RESPONSE


RANDOM RESPONSE

Suggested Exercise Steps1. Import the plate model. 2. Create a non-spatial field for the load. 3. Create a frequency dependent load case.4. Create a point element where the large mass will be applied.5. Create a RBE2 to connect the point element to the plate.6. Assign a 1e8 pound mass to the point element.7. Create the time dependent force.8. Modify the original constraint from the imported database.9. Submit the model to MSC.Nastran for analysis.10. Create a Non Spatial field for the Random Analysis.11. Open MSC.Random to prepare for Random Analysis. Create XY

Plots of the PSD Response.


CREATE NEW DATABASE

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


a

b c

d

e

f

g


Step 1. File / Import



b. Enter prob10B for Job Name.



Labels icon.

a

c

b

d

e

fg

h


e

f

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

Create a Non Spatial field for the load definition.


b. Enter field for the Field Name.


d. Click Input Data.e. Enter the data shown

in the table.f. Click OK.g. Click Apply.

a

b

c

d

g


Step 3. Load Cases: Create

Create a Frequency Dependent load case.

a. Load Cases: Createb. 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.


a

c

d

e

f g

b


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 ischecked.

a

b

c

e

fg

h

id


Step 5. Elements: Create / MPC / RBE2

Create a RBE2 to connect the Point element to the plate.


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

gh

i

c

d

e

f


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

b

c

d

e

f

g

i

j

h


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

Create the time dependent Force.




d. Enter <,,1e8> for Force, and select field for the Time/Freq. Dependent Field.



Filter to FEM.h. Select Node 9999.i. Click Add, and click OK.j. Click Apply.

a

b

c

d

e

f

g

h

i

j

i


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



b. Click on constraint in the Select Set to Modify box to select it.


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

b

c

d

e

f

h

i

j

g

i


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

b

c

d

e

f

h

g

i




a. Click on Subcases. b. Select random from the

Available Subcases field.



e. Enter the frequency data shown in the table.

f. Click OK.

a

b

c

d

e

f




a. Select Crit. Damp. (CRIT).

b. Click on DEFINE MODAL DAMPING.

c. Enter the damping information shown in the table.

d. Click OK.

e. Click OK.

a

b

c

d e





b. Select Accelerations in the Select Result Type box.

c. Click OK.d. Click Apply.e. Click Cancel.

a

b

c

d e




a. Click on Subcase Select.

b. Select random and unselect Default.


a

b

cd


e

f

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

Create a Non Spatial field for the Random Analysis.


b. Enter Random for the Field Name.


d. Click Input Data.e. Enter the data shown

in the table.f. Click OK.g. Click Apply.

a

b

c

d

g


Step 11. Utilities / Applications / MSC.Random

Open MSC.Random to prepare for Random Analysis.

a. Utilities / Applications / MSC.Random.

b. Select RMS ANALYSIS.

a

b


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 Fieldand select Random from the PSD Input fields box.

h. Click Close.i. Click Apply.

a

b

c

d

e

f g

h

i

a



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

bc

de

f



Create XY Plots of the PSD Response (cont.).

a. Select the node at the tip center.

b. Click Apply.

a

b




a. Select the node at the tip corner.

b. Click Apply.

a

b




a. Change the Plot Type to CRMS.

b. Click Apply.

a

b




a. Select the node at the tip center.

b. Click Apply.

a

b




a. Select Node 9999.b. Click Apply.

a

b


WORKSHOP 11

RANDOM ANALYSIS


ObjectivesDefine 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.

Workshop 11 – Random Analysis


Model DescriptionUsing 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

Table 11.2


50.00

Figure 11.1 - Loads and Boundary Conditions


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA




ID SEMINAR, PROB11SOL 111TIME 30CEND TITLE= FREQUENCY RESPONSE WITH PRESSURE AND POINT LOADSSUBTITLE= USING THE MODAL METHOD WITH LANCZOSECHO= UNSORTEDSPC= 1SET 111= 11, 33, 55 DISPLACEMENT(SORT2, PHASE)= 111METHOD= 100FREQUENCY= 100SDAMPING= 100RANDOM= 100SUBCASE 1LABEL= PRESSURE LOADDLOAD= 100LOADSET= 100SUBCASE 2LABEL CORNER LOADDLOAD= 200LOADSET= 100$OUTPUT (XYPLOT)$XTGRID= YESYTGRID= YESXBGRID= YESYBGRID= YESYTLOG= YESYBLOG= NOXTITLE= FREQUENCY (HZ)YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASEXYPLOT DISP RESPONSE / 11 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDE

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

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



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$RANDPS, 100, 1, 1, 1., 0., 100RANDPS, 100, 2, 2, 1., 0., 200RANDPS, 100, 1, 2, 1., 0., 300RANDPS, 100, 1, 2, 0., 1.0, 400$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




Windows Users:



Submit the input file to MSC.Nastran for analysisTo submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob11.bdf scr=yes. Monitor the run using the UNIX pscommand. To submit the MSC.Nastran .dat file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob11 scr=yes. Monitor the run using the UNIX ps command.

Unix Users:



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.


WORKSHOP 12

COMPLEX MODES OF A PILE DRIVER


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

Workshop 12 – Complex Modes of a Pile Driver


Problem DescriptionThe 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


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Create the model by the edit method.3. Create element properties.4. Create the constraint at the ground.5. Create the input file.6. Submit the input file for MSC.Nastran analysis.7. Review the .F06 file.8. Attach the XDB file.9. View the results.











a

b

e

d

cg

f


Step 2. Create the Model by Edit Method

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

c

b

d

e

f 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



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.

a

c

b

d f

e



Create the 2 mass elements at Node 1 and Node 2.


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

c

b

d g

f

e h

i



Create the damper elements connecting Node 2 and 3.


b. Select Bar for Shape.c. Uncheck Auto

Executed. Node 1 = Node 2.e. Node 2 = Node 3.f. Click Apply.

a

c

b

d

g

f

e


Step 3. Create Element Properties

a

d

b

c

ef

g

h

i

jk

l

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.


Step 3. Create Element Properties (cont.)

a

d

b

c

ef

g

h

i

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.

j

k

l



a

d

b

c

e

f

g

h

i

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


h. Make sure the Beam Element icon is selected.

i. Select Element 5.j. Click Add.k. Click Apply.

j

k



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


h. Click the Point Element icon.


a

d

b

c

gij

k

e

f

h



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


h. Make sure the Point Element icon is selected.


a

d

b

c

gij

k

e

f

h


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 <T1 T2 T3>.


Application Region…

g. Select FEM as Geometry Filter.

h. Select Node 3.i. Click Add.j. Click OK.k. Click Apply.

a

d

b

c ef

g

h

i

j

k


b


d

e

f

a

c

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…



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

d

a

c



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.



ID SEMINAR, PROB12

SOL 107

TIME 5

CEND

TITLE= TWO-DOF MODEL (IMAC 8, PG 891)

SUBTITLE= COMPLEX MODES

DISPLACEMENT= ALL $ DEFAULT= REAL, IMAGINARY

SPC= 100

CMETHOD= 99

$

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

CONM2, 202, 2, , 1.5

SPC, 100, 3, 1

$

$ DEFINE DAMPER OF 30 BETWEEN GRIDS 2 AND 3

$

CVISC, 101, 1, 2, 3

PVISC, 1, 30.

$

ENDDATA





Windows Users:




Unix Users:



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.



While still editing prob12.f06, search for the word:

E I G E N V A L U E (spaces are necessary).



Step 9. Compare the Results (cont.)




Step 10. Attach the XDB File

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…


a

b

a

e

d

c


Step 11. View the Results

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 Optionsicon.

e. Set the Complex No. as: Imaginary.

f. Click Apply.

a

b

c

d

e

f


Step 11. View the Results (cont.)


WORKSHOP 13

NOLINS IN LINEAR TRANSIENT


ObjectivesRepresent 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.

Workshop 13- Nolins in Linear Transient


Model Description


Figure 13.1 Car Traveling Over a Speed Bump



Figure 13.2 Force vs Relative Velocity


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. Generate a finite element representation of the model using (GRID), (CBAR), and

(CELAS2) elements.2. Define material (MAT1) and element (PBAR) properties.3. Constraints to eliminate rigid-body modes (SPC1).4. Define non-structural variables (CONM2).5. Specify scalar damper property and connection (CDAMP2).6. Define extra points (EPOINT).7. Define dynamic transfer functions (TF).8. Add non-linear portion of the spring (NOLIN1).9. Add non-linear portion of the damper (NOLIN4).10. Define the time-varying load (DAREA & TLOAD2).11. Define the time delay (DELAY).12. Specify integration time step.13. Prepare the model for direct transient analysis.14. Request response in terms of nodal displacement and non-linear load output.15. Generate an input file and submit it to the MSC.Nastran solver for direct transient analysis.16. Review the results, specifically the xy ploy of nodal displacements and non-linear load.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create and review the MSC.Nastran input file.2. Submit the input file to MSC.Nastran for analysis.3. Review the .f06 file.4. Create a database.5. Read the .op2 output file.6. View results.

Workshop 13 – Nolins in Linear Transient


Step 1: Create and Review Input File

ASSIGN OUTPUT2 = ’prob13.op2’, UNIT=12ID NAS102, WORKSHOP13SOL 109TIME 100CEND TITLE= SIMPLE CAR MODEL WITH NOLINEARSUBTITLE= SPRINGS AND DAMPERS RUNNING OVER A BUMPLABEL= SOL 109, CONSTANT DELTA TIMESEALL= ALL SPC= 100TFL= 100NONLINEAR = 100DLOAD = 100TSTEP = 100DISPLACEMENT(PLOT)= ALLNLLOAD(PLOT)= ALL$OUTPUT(XYPLOT)CSCALE=1.3XAXIS= YESYAXIS= YESXGRID LINES= YESYGRID LINES= YESXTITLE= TIME (SEC)YTITLE= VERTICAL DISPLACEMENT OF POINT 1XYPLOT DISP/1(T2)YTITLE= VERTICAL DISPLACEMENT OF POINT 2XYPLOT DISP/2(T2)YTITLE= VERTICAL DISPLACEMENT OF POINT 3XYPLOT DISP/3(T2)YTITLE= VERTICAL DISPLACEMENT OF POINT 4XYPLOT DISP/4(T2)YTITLE= VERTICAL DISPLACEMENT OF POINT 5XYPLOT DISP/5(T2)YTITLE= NONLINEAR FORCES AT POINT 1XYPLOT NONLINEAR/1(T2)

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

YTITLE= NONLINEAR FORCES AT POINT 2XYPLOT NONLINEAR/2(T2)$BEGIN BULKPARAM,POST,-1PARAM,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, 5SPC1, 100, 13456, 3, 4$$ SYSTEM WILL HAVE A NATURAL FREQUENCY OF 1 HZ $ WITH CRITICAL DAMPING OF 1 PERCENT$CONM2, 10, 1, ,2.5CONM2, 15, 2, ,2.5CONM2, 20, 5, ,5.


Step 1: Create and Review Input File (cont.)$CELAS2, 30, 197.4, 1, 2, 3, 2CELAS2, 40, 197.4, 2, 2, 4, 2$CDAMP2, 50, 1.88, 1, 2, 3, 2CDAMP2, 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.$$ ADD NONLINEAR PORTION OF SPRINGS$NOLIN1, 100, 1, 2, 197.4, 101, 0, 111NOLIN1, 100, 2, 2, 197.4, 102, 0, 111TABLED2, 111, -2.0,, -1., 1., 0., 0., 1., 0.,ENDT$$ 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 INFORMATIONTSTEP, 100, 200, .05, 1$ENDDATA




Windows Users:




Unix Users:


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).


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











a

b

e

d

cg

f


Step 5. Read Output File

Read the .op2 output file.a. Analysis: Access

Results / Read Output2 / Both.



a

b

c

d

e





b. Under Select Result case(s), click on SPRINGS AND DAMPERS RUNNING OVER A BUMP, 0 of 201 subcases.



a

b

c

d

e f



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.



e. Select the top left node (Node 1).

f. Click Apply.

b

a

c

d

e

f



Nonlinear Forces at Point 1



Create a X-Y graph of displacement results (cont.).a. Under Select Nodes,

select the top right node (Node 2).

b. Click Apply.

b

a

Nonlinear Forces at Point 2



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

e



Vertical Displacement at Point 1



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.

b

a

c

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


WORKSHOP 14a

MODAL ANALYSIS OF A BEAM


ObjectivesPerform 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.

Workshop 14a – Modal Analysis of a Beam


Figure 14a.1 – Grid Coordinates and Element Connectivites

Problem DescriptionThe 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.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



Hand Calculations:

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



From Theory:

Mode Kn fn

1 9.87 23.85 Hz

2 39.5 95.46

3 88.8 214.59 Hz


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Create the geometry.3. Create the finite element model and mesh the surface.4. Create the nodal displacements.5. Create a set of material properties.6. Define the bar properties.7. Generate the input file for analysis.8. Submit the input file to MSC.Nastran for analysis.9. Attach the XDB file.10. View the results.











a

b

e

d

cg

f


e

Step 2. Create the Geometry

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

c

b

d

e

f


Step 3. Create the Finite Element Model

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.

a

e

d

cb

d


Step 4. Create the Nodal Displacements

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 <T1 T2 T3>.e. Enter <0, , > for Rotations

<R1 R2 R3>.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.

a

d

b

c

e

f

g

h

i

j

k

l


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 <T1 T2 T3>.d. Enter <0, , > for Rotations

<R1 R2 R3>.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.

a

d

b

c

ef

g

h

i

j


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 <T1 T2 T3>.d. Enter <0, 0, > for Rotations

<R1 R2 R3>.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.

a

d

b

c

ef

g

h

i

j



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.

aa

b

c

d

f

e

gh


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 Libraryicon.

b

c

d

e

f


Step 6. Define the Bar Properties (cont.)

a

a. Enter beam as New Section Name.

b. Enter the following:H = 2W1 = 1W2 = 1t = 0.1t1 = 0.1t2 = 0.1

c. Click OK.

b

c


Step 6. Define the Bar Properties (cont.)

a

b

c

d

e

a. Enter Coord 0.2 for Bar Orientation.

b. Click OK.c. Select Curve 1 for Select

Members.d. Click Add.e. Click Apply.


b


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 0.00259for Wt.-Mass Conversion.



d

e

f

a

c

g

h

i

g


e

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.

b

d

a

c


gfh



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.



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select prob14a.bdf or prob14.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo submit the MSC.Nastran .bdf file for analysis, find an available UNIX shell window. At the command prompt enter: nastran prob14a.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 prob14a scr=yes. Monitor the run using the UNIX ps command.

Unix Users:




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



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.

a

b

a

e

d

c



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.


d. Click Apply.

a

b

c d

d


WORKSHOP 14b

NORMAL MODES WITH DIFFERENTIAL STIFFNESS


ObjectivesAnalyze 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).

Workshop 14b – Normal Modes With Differential Stiffness


Figure 14b.1 – Grid Coordinates and Element Connectivites

Problem DescriptionThe 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.

Workshop 14b – Normal Modes with Differential Stiffness



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



Theoretical Solution:

For Static Load:


MSC.Nastran Users – Modify an MSC.Nastran input file using a text editor1. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Open database created in Problem 14a.2. Create the force.3. Generate the input file for analysis.4. Submit the input file to MSC.Nastran for analysis.5. Review the F06 file.6. Attach the XDB file.7. View the results.





Open database created in Problem a14a named probl14a.db.

a. File/Open.b. Select prob14a.db.c. Click OK.

b

c

a


Step 2. Create the Force

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

<F1 F2 F3>.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.

a

d

b

c

e

fg

h

i

j

k


b


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 0.00259for Wt.-Mass Conversion.



d

e

fa

c

g

hi


e

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 andEIGRL,10, , , 3.

f. Click OK.

b

d

a

c


f


e

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.

b

d

a

c


f gh



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.


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:



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



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select prob14b.bdf or prob14b.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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.

Unix Users:



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



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.

a

b

a

e

d

c



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.


d. Click Apply.

a

b

c

d


WORKSHOP 15

WEIGHT MINIMIZATION OF A THREE BAR TRUSS


ObjectivesMinimize 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.

Workshop 15 – Weight Minimization of a Three Bar Truss


Model DescriptionYou 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


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. Generate the analysis model. The nodes (GRID) and element connectivities (CROD)

should be defined manually.2. Define material (MAT1) and element (PROD) properties.3. Apply fixed boundary constraints (SPC1) to the upper nodes.4. Create the appropriate design optimization model.5. Define the design variables (DESVAR).6. Relate one design variable to another design variable (DLINK).7. Define design variable to analysis model parameter relations (DVPREL).8. Specify design sensitivity response quantities (DRESP1).9. Define constraints (DCONSTR).10. Define optimization control parameters (DOPTPRM).11. Prepare the model for linear static analysis and normal modes analysis using Lanczos

Method.PARAM, WTMASS, 0.00259

12. Generate an input file and submit it to MSC.Nastran for structural optimization analysis.13. Review the results, specifically the eigenvalues and the design variable history.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Create elements that make up the truss.3. Define the material.4. Create the material properties.5. Create load/boundary conditions.6. Create a load case.7. Create model variables.8. Create a design study.9. Create the input file.10. Review the input file for MSC.Nastran users.11. Submit the input file to MSC.Nastran for analysis.12. Review the .F06 file.13. Read the .op2 output file.14. View results.











a

b

e

d

cg

f


Step 2. Create Elements

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

de

f

a b

f


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.

c

d

a

b


Step 3. Define the Material

We will set aluminum as the material of the plate.

a. Materials: Create / Isotropic / Manual Input.

b. Select on Material Nameand enter alum.

c. Select Input Properties.d. Enter:

Elastic Modulus: 10e6.Poisson Ratio: 0.33.Density: 0.1.

e. OK.f. Apply.

a

b

c

d

ef



a

b

c

de

g

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.

fh

i

h


Step 4. Create Material Properties (cont.)

a

b

c

d


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.

f

e

e



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.



Filter to FEM.h. Select Node 1:3 and

click Add.i. Click OK.j. Click Apply.

a

b

c

d

e

f

g

h

i

j

h




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

b

c

d

e

f

g

i

h

g

j



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.


a

b

c

e

f

d


Step 7. Create Model Variables

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.

a

b

c

f

d

e

g


Step 8. Create Design Study

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.

ab

c

f

d

e


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 Frequencyfor 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.

a

b

c

f

d

e

g

h i

j k

l m


b

a

c


Generate the input file for analysis. a. Analysis: Optimize / Entire




d

e



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-thcycle where n =.

g. Click OK.a

b

c

d

ef

g




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.

a

c

b

d e




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.

a

b

c

de



ASSIGN OUTPUT2=’prob15.op2’, UNIT=12ID NAS102, WORKSHOP 15TIME 10SOL 200 $ OPTIMIZATIONCENDTITLE= SYMMETRIC THREE BAR TRUSS DESIGN OPTIMIZATION - VARIATION OF D200X1SUBTITLE= GOAL IS TO MIN WT WHILE KEEPING THE 1ST MODE BETWEEN 1500-1550 HZECHO= SORTSPC= 100DISP(PLOT) ALLDESOBJ(MIN)= 100 $ (DESIGN OBJECTIVE = DRESP ID)DESSUB= 200 $ DEFINE CONSTRAINT SET FOR BOTH SUBCASESSUBCASE 1

ANALYSIS= MODESMETHOD= 10

BEGIN BULK$$----------------------------------------------------------------------$ ANALYSIS MODEL$----------------------------------------------------------------------$EIGRL, 10, , , 2PARAM, POST, -1PARAM, PATVER, 3.0$$ GRID DATA$ 2 3 4 5 6 7 8 9 10GRID, 1, , -10.0, 0.0, 0.0GRID, 2, , 0.0, 0.0, 0.0GRID, 3, , 10.0, 0.0, 0.0GRID, 4, , 0.0, -10.0, 0.0$ SUPPORT DATASPC, 100, 1, 123456, , 2, 123456SPC, 100, 3, 123456, , 4, 3456$ ELEMENT DATACROD, 1, 11, 1, 4CROD, 2, 12, 2, 4



Step 10: Review Input File for MSC.Nastran Users (cont.)CROD, 3, 13, 3, 4$ PROPERTY DATAPROD, 11, 1, 1.0PROD, 12, 1, 2.0PROD, 13, 1, 1.0MAT1, 1, 1.0E+7, , 0.33, 0.1$PARAM, WTMASS, .00259$$----------------------------------------------------------------------$ DESIGN MODEL$----------------------------------------------------------------------$$...DESIGN VARIABLE DEFINITION$$DESVAR,ID, LABEL, XINIT, XLB, XUB, DELXV(OPTIONAL)DESVAR, 1, A1, 1.0, 0.1, 100.0DESVAR, 2, A2, 2.0, 0.1, 100.0DESVAR, 3, A3, 1.0, 0.1, 100.0$$...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$$DVPREL1,ID, TYPE, PID, FID, PMIN, PMAX, CO, , +$+, DVID1, COEF1, DVID2, COEF2, ...DVPREL1, 10, PROD, 11, 4, , , , , +DP1+DP1, 1, 1.0DVPREL1, 20, PROD, 12, 4, , , , , +DP2+DP2, 2, 1.0DVPREL1, 30, PROD, 13, 4, , , , , +DP3+DP3, 3, 1.0$$...STRUCTURAL RESPONSE INDENTIFICATION$$DRESP1 ID LABEL RTYPE PTYPE REGION ATTA ATTB ATT1 +$+ ATT2 ...DRESP1 100 W WEIGHT


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




Windows Users:




Unix Users:




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

Design Variable Initial Value Optimization Value Iteration Value

1 __________ ___________ __________

2 __________ ___________ __________

3 __________ ___________ __________


Step 13. Read Output File

Read the .op2 output file.a. Analysis: Access

Results / Read Output2 / Result Entities.


c. Select prob15.op2.d. Click OK.e. Click Apply.

a

b

c

d

e



Create a X-Y Plot of the results.a. XY-Plot: Post / XYWindowb. Under Select Current XY

Window, select DesignVariableHistory.

c. Under Post/Unpost XYWindows, select DesignVariableHistory.

d. Click Apply.

a

b

c

d



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.

a

b

c

d



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.

a

b

c

d


ObjectivesPerform 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.

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


Model DescriptionThe 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



From Theory:

Hand Calculations:

Table 1a.1


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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.

PARAM, COUPMASS, 1EIGRL (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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Create the geometry.3. Create a finite element mesh.4. Create load/boundary conditions.5. Define the material.6. Create material properties.7. Create an input file.8. Review the input file for MSC.Nastran users.9. Submit the input file to MSC.Nastran for analysis.10. Review the .F06 file.11. Attach the XDB file.12. View results.





Create a new database named probap1a.db.

a. File / New.b. Enter probap1a as the

file name.c. Click OK.d. Choose Default




a

b

e

d

c g

f


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

bc

d

e


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

b

c

d


Step 4. Create Loads/Boundary Conditions


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.



Filter to Geometry.h. Select the leftmost

point (Point 1).i. Click Add and OK.j. Click Apply.

a

b

c

d

e

f

g

h

i

i

j


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


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.

a

b

c

d

e

f

g

h

i

h


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


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.

a

b

c

d

e

f

h

g

g


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

b

c

d

e

f

g


Step 6. Create Properties


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

b

c

de

g

h

i

h

f



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.

a

b

c

d

e

f

g

h




a. Click on Subcases. b. Select Default from the



d. Change the Number of Desired Roots to 3.

e. Click OK.f. Click Apply.g. Click Cancel.h. Click Apply.

a

c

b

d

e

f gh


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.




SOL 103TIME 600CENDTITLE = Normal Modes Example (SI UNITS)SUBCASE 1

METHOD = 1SPC = 1VECTOR(SORT1,REAL)=ALL

BEGIN BULKPARAM COUPMASS1EIGRL 1 3 0PBAR 1 1 5000. 1.04+6CBAR 1 1 1 2 0. 1. 0.CBAR 2 1 2 3 0. 1. 0.CBAR 3 1 3 4 0. 1. 0.CBAR 4 1 4 5 0. 1. 0.CBAR 5 1 5 6 0. 1. 0.CBAR 6 1 6 7 0. 1. 0.CBAR 7 1 7 8 0. 1. 0.CBAR 8 1 8 9 0. 1. 0.CBAR 9 1 9 10 0. 1. 0.CBAR 10 1 10 11 0. 1. 0.MAT1 1 206840. .32 7.83-9GRID 1 0. 0. 0. 345GRID 2 100.000 0. 0. 345GRID 3 200.000 0. 0. 345GRID 4 300.000 0. 0. 345GRID 5 400.000 0. 0. 345GRID 6 500. 0. 0. 345GRID 7 600.000 0. 0. 345GRID 8 700.000 0. 0. 345GRID 9 800.000 0. 0. 345GRID 10 900.000 0. 0. 345GRID 11 1000. 0. 0. 345SPC1 1 1234 1SPC1 1 234 11ENDDATA

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:



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select probap1a.bdf or probap1a.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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 pscommand. 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.

Unix Users:



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


Step 11. Attach XDB File

Attach the XDB file.a. Analysis: Access



c. Select probap1a.xdb.d. Click OK.e. Click Apply.

a

b

c

d

e



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.

a

b

c

d

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

AP1b-1NAS102, Appendix 1b, January 2004Copyright© 2004 MSC.Software Corporation

APPENDIX 1b

NORMAL MODES WITH DIFFERENTIAL STIFFNESS


ObjectivesAnalyze 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).

Appendix 1b – Normal Modes with Differential Stiffness


Model DescriptionThe 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



For static load:

Theoretical solution:

Table 1b.1


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. Open the database created in Appendix 1a.2. Apply a force load to one end of the model.3. Ensure that the analysis is set to nonlinear static (SOL 106).4. Prepare nonlinear analysis to also analyze for normal modes (PARAM

NMLOOP, EIGRL, PARAM LGDISP, NLPARM).5. Review the results, specifically the eigenvectors.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Open an existing database.2. Create loads/boundary conditions.3. Create an input file.4. Review the input file for MSC.Nastran users.5. Submit the input file to MSC.Nastran for analysis.6. Review the .F06 file.7. Attach the XDB file.8. View results.




Step 1. Open Database

Open the database probap1a.db.

a. File / Open.b. Enter probap1a as the file

name.c. Click OK.

a

b

c


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

b

c

d

e

f

g

h

i

h




a. Enter probap1b as the Job Name.

b. Click on Solution Type. c. Select Nonlinear Static

as the Solution Type. d. Click on Solution


Calculation to Coupled.f. Click OK.g. Click OK.

a

b

c

d

e

fg



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.

a

d

c

b

e

f




a. Click on Subcases. b. Select Default from the



d. Change the Number of Load Increments to 5.

e. Click OK.f. Click Apply.g. Click Cancel.h. Click Apply.

a

c

bd

e

f gh


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.




SOL 106TIME 600CEND$TITLE = NORMAL MODES WITH DIFFERENTIAL STIFFNESSMETHOD = 10SUBCASE 1

NLPARM = 1SPC = 1LOAD = 1DISPLACEMENT(SORT1,REAL)=ALL

$BEGIN BULKPARAM COUPMASS 1PARAM LGDISP 1NLPARM 1 5 AUTO 5 25 PW NO + A+ A .001 1.-7PARAM,NMLOOP,5$EIGRL,10,,,3PBAR 1 1 5000. 1.04+6CBAR 1 1 1 2 0. 1. 0.CBAR 2 1 2 3 0. 1. 0.CBAR 3 1 3 4 0. 1. 0.CBAR 4 1 4 5 0. 1. 0.CBAR 5 1 5 6 0. 1. 0.CBAR 6 1 6 7 0. 1. 0.CBAR 7 1 7 8 0. 1. 0.CBAR 8 1 8 9 0. 1. 0.CBAR 9 1 9 10 0. 1. 0.CBAR 10 1 10 11 0. 1. 0.$MAT1 1 206840. .32 7.83-9GRID 1 0. 0. 0. 345GRID 2 100.000 0. 0. 345

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:

GRID 3 200.000 0. 0. 345GRID 4 300.000 0. 0. 345GRID 5 400.000 0. 0. 345GRID 6 500. 0. 0. 345GRID 7 600.000 0. 0. 345GRID 8 700.000 0. 0. 345GRID 9 800.000 0. 0. 345GRID 10 900.000 0. 0. 345GRID 11 1000. 0. 0. 345SPC1 1 1234 1SPC1 1 234 11FORCE 1 11 0 1.+7 1. 0. 0.ENDDATA



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select probap1b.bdf or probap1b.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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 pscommand. 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.

Unix Users:



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


Step 7. Attach XDB File

Attach the XDB file.a. Analysis: Access



c. Select probap1b.xdb.d. Click OK.e. Click Apply.

a

b

c

d

e



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.

a

b

c

d

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

AP1c-1NAS102, Appendix 1c, January 2004Copyright© 2004 MSC.Software Corporation

APPENDIX 1c

NORMAL MODES WITH DIFFERENTIAL STIFFNESS, USING

STATSUB


ObjectivesPerform 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.

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


Model DescriptionThe 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



For static load:

Theoretical solution:

Table 1c.1


MSC.Nastran Users - Generate a MSC.Nastran input file using a text editor1. 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).

PARAM WTMASS 0.00259PARAM COUPMASS 1EIGRL (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.



ID SEMINAR, PROB1C______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________CEND________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________BEGIN BULK



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Open an existing database.2. Create an input file.3. Review the input file for MSC.Nastran users.4. Modify the input file.5. Submit the input file to MSC.Nastran for analysis.6. Review the .F06 file.




Step 1. Open Database

Open the database probap1a.db.

a. File / Open.b. Enter probap1a as the file

name.c. Click OK.

a

b

c




a. Enter probap1c as the Job Name.

b. Click on Solution Type. c. Select Linear Static as

the Solution Type. d. Click on Solution


Calculation to Coupled.f. Click OK.g. Click OK.

a

b

c

d

e

f g



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.

a

d

c

b

ef

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



SOL 101CENDECHO = NONESUBCASE 1

SPC = 2LOAD = 2DISPLACEMENT(SORT1,REAL)=ALLSPCFORCES(SORT1,REAL)=ALLSTRESS(SORT1,REAL,VONMISES,BILIN)=ALL

BEGIN BULKPARAM POST -1PARAM PATVER 3.PARAM AUTOSPC NOPBAR 1 1 5000. 1.041+6 1.CBAR 1 1 1 2 0. 1. 0.CBAR 2 1 2 3 0. 1. 0.CBAR 3 1 3 4 0. 1. 0.CBAR 4 1 4 5 0. 1. 0.CBAR 5 1 5 6 0. 1. 0.CBAR 6 1 6 7 0. 1. 0.CBAR 7 1 7 8 0. 1. 0.CBAR 8 1 8 9 0. 1. 0.CBAR 9 1 9 10 0. 1. 0.CBAR 10 1 10 11 0. 1. 0.MAT1 1 206840. .32 7.833-9GRID 1 0. 0. 0.GRID 2 100.000 0. 0.GRID 3 200.000 0. 0.GRID 4 300.000 0. 0.GRID 5 400.000 0. 0.GRID 6 500. 0. 0.GRID 7 600.000 0. 0.GRID 8 700.000 0. 0.GRID 9 800.000 0. 0.GRID 10 900.000 0. 0.

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:

GRID 11 1000. 0. 0.SPCADD 2 1 3 4LOAD 2 1. 1. 1SPC1 1 1234 1SPC1 3 234 11SPC1 4 345 1 THRU 11FORCE 1 11 0 1.+7 1. 0. 0.ENDDATA 052ec265


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. Open the input file, probap1c.bdf, using any text editor.2. Locate and replace the text SOL 101 with SOL 103.3. Add a new subcase after the SUBCASE 1 section and before the BEGIN

BULK line:SUBCASE 2

STATSUB = 1METHOD = 1SPC = 2VECTOR = ALL

4. Add the following after the BEGIN BULK line:EIGRL, 1, , ,3

5. Save the changes to the .bdf file and close the text editor. You are now ready to submit the input file for analysis.



Submit the input file to MSC.Nastran for analysisDouble click on MSC.Nastran icon.Select probap1c.bdf or probap1c.dat and click Open.Enter scr=yes in the Optional Keywords field.Click Run.

Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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 pscommand. 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.

Unix Users:



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

AP7-1NAS102, Appendix 7, January 2004Copyright© 2004 MSC.Software Corporation

APPENDIX 7

DIRECT TRANSIENT RESPONSE WITH BASE EXCITATION


ObjectivesDefine 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.

Appendix 7 – Direct Transient Response With Base Excitation


Model DescriptionUsing the direct method, determine the transient response to a unit acceleration sine pulse of 250Hz applied at the base in thez 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.





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.PARAM, G, 0.06PARAM, 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Import an existing model.3. Create a load case.4. Create a 0D mass.5. Create a RBE2 to connect the mass to the plate.6. Create time dependent fields.7. Create load/boundary conditions.8. Create a MSC.Nastran input file.9. Review the MSC.Nastran input file.10. Submit the input file to MSC.Nastran for analysis.11. Review the .F06 file.12. Attach the XDB file.13. View results.











a

b

e

d

c g

f








e. Click Show Labels.f. Switch to Iso 3 View.

b

c

ac

d

e f

d








a

b

c

d

e

f

g


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


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

b

d

g

h

i

e

f

c

h

h


Step 5. Create a RBE2

Create a RBE2 to tie the mass to the drive point.


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

d

f

kc

eg

h

i j





b. Enter time_dependent_acceleration for the Field Name.


a

b

ce

d






h

f

gi j





k

m

l



Create the time-dependent unit acceleration.

a. Loads/BCs: Create / Acceleration / Nodal.

b. Enter unit_acceleration for the New Set Name.


d. Enter <0, 0, 2.588>for Trans. Accel., and select time_dependent_acceleration for the Time/Freq. Dependent Field.


Application Region.g. Choose FEMh. Select the center

node on the left side of the plate (Node 23).


j. Click Apply.

a

b

c

d d

e

f

g

j

i

h

i





b. Click on spc1.1 in the Select Set to Modify box to select it.


d. Modify Translations to <0,0,>.


a

b

c

d

e

f

e


b

a

c






d

e









Mass Conversion.

g. Enter 0.06 for Struct. Damping Coefficient and 1571 for W3, Damping Factor.


a

b

cd

e

f

g

i

h








e. Change No. of Time Steps to 200, and Delta-T to 0.0002.


ac

b

d

e

f

g






c. Under Select Result Type, select Velocities and Accelerations.

d. Click OK.e. Click Apply.f. Click Cancel.

a

b

f

c

e

b

d







a

b

c

d

b



ID SEMINAR, PROB7SOL 109TIME 30CENDTITLE = TRANSIENT RESPONSE WITH BASE EXCITATIONSUBTITLE = USING DIRECT TRANSIENT METHOD, NO REDUCTIONECHO = UNSORTEDSPC = 200SET 111 = 23, 33DISPLACEMENT (SORT2) = 111VELOCITY (SORT2) = 111ACCELERATION (SORT2) = 111SUBCASE 1DLOAD = 500TSTEP = 100$OUTPUT (XYPLOT)XGRID=YESYGRID=YESXTITLE= TIME (SEC)YTITLE= BASE ACCELERATIONXYPLOT ACCELERATION RESPONSE / 23 (T3)YTITLE= BASE DISPLACEMENT XYPLOT DISP RESPONSE / 23 (T3)YTITLE= TIP CENTER DISPLACEMENT RESPONSEXYPLOT DISP RESPONSE / 33 (T3)$BEGIN BULK$$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE$INCLUDE ’plate.bdf’PARAM, COUPMASS, 1PARAM, WTMASS, 0.00259$


$ SPECIFY STRUCTURAL DAMPING$PARAM, G, 0.06PARAM, 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




Windows Users:



Submit the input file to MSC.Nastran for analysisTo 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.

Unix Users:






Time T3

0 = ___________

.02 = ___________

.04 = ___________




Time 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 = ___________



Velocity at Grid 33

Time T3

0 = ___________

.02 = ___________

.04 = ___________

Now search for the word A C C E L (spaces are necessary)


Time T3

0 = ___________

.02 = ___________

.04 = ___________




Time T3

0 = ___________

.02 = ___________

.04 = ___________







a

b

c

d

e








a

b

c

d

e f



Create a X-Y graph of displacement results (cont.).a. Select Displacement,

Translational for the Select Y Result field.




e. Select the center node on the left edge of the plate (Node 23).

f. Click Apply.

b

a

c

d

e

f



Base Displacement at Node 23





b. Click Apply.

b

a

Tip Displacement at Node 33




select Velocities, Translational.



e. Click Apply.

b

a c

d

e



Base Velocity at Node 23





b. Click Apply.

b

a

Tip Velocity at Node 33




select Accelerations, Translational.



e. Click Apply.

b

a c

d

e



Base Acceleration at Node 23





b. Click Apply.

b

a

Tip Acceleration at Node 33


APPENDIX 8

ENFORCED MOTION WITH DIRECT FREQUENCY RESPONSE


ObjectivesDefine 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.

Appendix 8 – Enforced Motion with Direct Frequency Response


Model DescriptionUsing 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.





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

PARAM, G, 0.067. 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.



1 2 3 4 5 6 7 8 9 10



1 2 3 4 5 6 7 8 9 10

ENDDATA



MSC.Patran Users1. Create a new database.2. Import an existing model.3. Create a load case.4. Create a 0D mass.5. Create a MSC.Nastran input file.6. Review the MSC.Nastran input file.7. Submit the input file to MSC.Nastran for analysis.8. Review the .F06 file.9. Attach the XDB file.10. View results.











a

b

e

d

cg

f









b

c

ac

d

e

d



Create a frequency-dependent load case called frequency_response.

a. Load Cases: Create.b. Enter frequency_response




a

b

c

d

e

fg


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


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

b

d

g

h

i

e

f

c

h

h


b

a

c






d

e




a. Click on Solution Type. b. Select Frequency





Mass Conversion.

g. Enter 0.06 for Struct. Damping Coefficient.

h. Click OK.i. Click OK. a

b

cd

e

f

g

hi



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,,,310TABLED4,310,0.,1.,0.,10000,+,0.,0.,-39.4784,ENDTDAREA,600,11,3,25.8799c. Click on the Case Control

Section.d. Enter DLOAD=500 in the

field.e. Click OK.

a

b

c

d

e





frequency_response from the Available Subcases field.



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


a

c

b

d

e

f

g






c. Click OK.d. Click Apply.e. Click Cancel.

a

b

d ec

b




a. Click on Subcase Select.b. Select frequency_response

and unselect Default.c. Click OK.d. Click Apply.

a

b

c

d

b



ID SEMINAR, PROB8SOL 108TIME 30CENDTITLE= FREQUENCY RESPONSE DUE TO .1 DISPLACEMENT AT TIPSUBTITLE= DIRECT METHODECHO= UNSORTEDSPC= 1SET 111= 11, 33, 55DISPLACEMENT(PHASE, SORT2)= 111SDISP(PHASE, SORT2)= ALLset 222 = 11OLOAD= 222SUBCASE 1DLOAD= 500FREQUENCY= 100$OUTPUT (XYPLOT)$XTGRID= YESYTGRID= YESXBGRID= YESYBGRID= YESYTLOG= YESYBLOG= NOXTITLE= FREQUENCY (HZ)YTTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER, PHASEXYPLOT DISP RESPONSE / 11 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT TIP CENTER, PHASEXYPLOT DISP RESPONSE / 33 (T3RM, T3IP)YTTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, MAGNITUDEYBTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER, PHASE


XYPLOT DISP RESPONSE / 55 (T3RM, T3IP)$BEGIN BULK$$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE$INCLUDE ’plate.bdf’PARAM, COUPMASS, 1PARAM, WTMASS, 0.00259$$ 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




Windows Users:




Unix Users:



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 atthe 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)



140 = ___________

380 = ___________





140 = ___________

600 = ___________



140 = ___________

1000 = ___________







a

b

c

d

e



Create a graph of Frequency vs. Displacement.


b. Under Select Result case(s), click on frequency_response, 0 of 50 subcases.



a

b

c

d

e f






c. Click on the Plot Options icon.

d. Change Complex No. asto Magnitude.

e. Click on Target Entities.f. Click in the Select Nodes

box and select the lower right node (Node 11).

g. Click Apply.

b

a

c

d

e

f

g




a. Click Plot Options.b. Change Complex No.

as to Phase.c. Click Apply.

a

b

Repeat the previous steps to plot nodes 33 and 55.

c

nas102 dynamic exercise

Documents

trademark of msc

modal analysis

software corporationworkshop

service marks of msc

response spectra9b

prior written consent

direct frequency response9a

normal modes