MSC.Software Corporation
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MSC.Nastran Dynamic Analysis
March 2004
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.
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TABLE OF CONTENTS
No.
Title
1.
Modal Analysis of a Flat Plate
2.
Modal Analysis of a Flat Plate using Static Reduction
3.
Direct Transient Response Analysis
4.
Modal Transient Response Analysis
5.
Direct Frequency Response Analysis
6.
Modal Frequency Response Analysis
6a.
Modal Frequency Response Analysis
7a.
Direct Transient Response with Base Excitation
8a.
Enforced Motion with Direct Frequency Response
9a.
Response Spectra
9b.
Response Spectra (cont.)
10.
Random Analysis
11.
Random Analysis
12.
Complex Modes of a Pile Driver
13.
Nolins in Linear Transient
14a. Modal Analysis of a Beam
14b. Normal Modes with Differential Stiffness
15.
Weight Minimization of a Three Bar Truss
Appendix
Title
1a.
Modal Analysis of a Beam (SI Units)
1b.
Normal Modes with Differential Stiffness (SI Units)
1c.
Normal Modes with Differential Stiffness, using STATSUB
7.
Direct Transient Response with Base Excitation
WORKSHOP 1
Objectives
Produce a MSC.Nastran input file.
Submit the file for analysis in MSC.Nastran.
Find the first five natural frequencies and mode shapes of the flat
plate.
a
b
Problem Description
For this workshop, use Lanczos method to find the first five natural
frequencies and mode shapes of a flat rectangular plate. One of the
edges is fixed (See Figure 1.2). Below is a finite element
representation of the rectangular plate. It also contains the geometric
dimensions. Table 1.1 contains the necessary parameters to
construct the input file.
Workshop 1 – Modal Analysis of a Flat Plate
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
Workshop 1 – Modal Analysis of a Flat Plate
Natural Frequency: Hertz
Where i = 1,2,3, …
j = 1,2,3, …
f
ij
λ
ij
2
2
πa
2
---
Eh
3
12
γ 1 ν
(
–
2
)
---1 2
⁄
=
Description: Clamped-Free-Free-Free
a = length of plate
b = width of plate
h = thickness of plate
i = number of half-waves in mode shape along horizontal axis
j = number of half-waves in mode shape along vertical axis
C = clamped edge
E = modulus of elasticity
F = free edge
S = simply supported edge
γ = mass per unit area of plate (μh for a plate material with density μ )
υ = Poisson ratio
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)
λ
ij2and (ij)
υ = 0.3
Mode Sequence
MSC.Nastran Users - Generate a MSC.Nastran input
file using a text editor
1. Define the plate structure using grid points (GRID) and elements
(CQUAD4).
2. Define material (MAT1) and element (PSHELL) properties.
3. Apply the fixed boundary constraints (SPC1).
4. Prepare the model for a normal modes analysis (SOL 103 and
PARAMs).
z
PARAM, WTMASS, 0.00259
z
PARAM, COUPMASS, 1
5. Create a complete input file prob1.dat. Also create a model file
plate.dat which contains only model data.
6. Go to step 9 under MSC.Patran users.
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
Workshop 1 – Modal Analysis of a Flat Plate
MSC.Patran Users
1. Create a new database.
2. Create a surface.
3. Create a finite element mesh.
4. Create material properties.
5. Create 2D shell properties.
6. Create boundary conditions.
7. Create an MSC.Nastran model file.
8. Create an MSC.Nastran input file.
9. Review the MSC.Nastran model file and input file.
10. Submit the model to MSC.Nastran for analysis.
11. Review the .F06 file.
12. Attach the XDB file.
13. View Results.
MSC.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
d
b
c
e
Step 3. Create Finite Element Mesh
Mesh the surface.
a. Elements: Create / Mesh / Surface.
b. Screen pick the surface c. 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
Step 5. Create 2D Shell Properties (cont.)
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
d
e
a. Click Select ApplicationRegion.
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
a
c
Step 6. Create Boundary Conditions (cont.)
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.
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
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. 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
Step 8. Create the Input File (cont.)
a
d
b
a
c
a. Select SPCFORCES(SORT1,RE AL)=All FEM. b. Click Delete. c. Click OK. d. Click Apply. e. Click Cancel. f. Click Apply.e
f
d
Step 8. Create the Input File (cont.)
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.
Step 9A: Review Input File for MSC.Nastran Users
ID SEMINAR, PROB1 SOL 103
TIME 600 CEND
TITLE = NORMAL MODES EXAMPLE ECHO = UNSORTED
SUBCASE 1
SUBTITLE= USING LANCZOS METHOD = 1 SPC = 1 VECTOR=ALL BEGIN BULK PARAM COUPMASS 1 PARAM WTMASS .00259 EIGRL 1 5 PSHELL 1 1 .1 1 1 CQUAD4 1 1 1 2 13 12 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 11 1 12 13 24 23 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 21 1 23 24 35 34 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 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 .282 GRID 1 0. 0. 0. =,*1,=,*0.5,== =9 GRID 12 0. .5 0. =,*1,=,*0.5,== =9 GRID 23 0. 1. 0. =,*1,=,*0.5,== =9 GRID 34 0. 1.5 0. =,*1,=,*0.5,== =9 GRID 45 0. 2. 0. =,*1,=,*0.5,== =9 SPC1 1 12345 1 12 23 34 45 ENDDATA
GRID 1 0. 0. 0. =,*1,=,*0.5,== =9 GRID 12 0. .5 0. =,*1,=,*0.5,== =9 GRID 23 0. 1. 0. =,*1,=,*0.5,== =9 GRID 34 0. 1.5 0. =,*1,=,*0.5,== =9 GRID 45 0. 2. 0. =,*1,=,*0.5,== =9 PSHELL 1 1 .1 1 1 CQUAD4 1 1 1 2 13 12 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 11 1 12 13 24 23 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 21 1 23 24 35 34 =,*1,=,*1,*1,*1,*1 =8 CQUAD4 31 1 34 35 46 45 =,*1,=,*1,*1,*1,*1 =8 MAT1 1 3.+7 .3 .282 SPC1 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 10: Submitting the Input File for Analysis
Submit the input file to MSC.Nastran for analysis
Double click on MSC.Nastran icon.
Select prob1.bdf or prob1.dat and click Open.
Enter scr=yes in the Optional Keywords field.
Click Run.
Step 10: Submitting the Input File for Analysis
Submit the input file to MSC.Nastran for analysis
To submit the MSC.Nastran .bdf file for analysis, find an available
UNIX shell window. At the command prompt enter: nastran
prob1.bdf scr=yes. Monitor the run using the UNIX ps command.
To submit the MSC.Nastran .dat file for analysis, find an available
UNIX shell window. At the command prompt enter: nastran prob1
scr=yes. Monitor the run using the UNIX ps command.
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.
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
WORKSHOP 2
MODAL ANALYSIS OF A FLAT
PLATE USING STATIC REDUCTION
Objectives
Reduce the dynamic math model, created in Workshop 1, to one with
fewer degrees of freedom.
Produce an MSC.Nastran input file.
Submit the file for analysis in MSC.Nastran.
Find the first five natural frequencies and mode shapes of the flat
plate.
Problem Description
For this example, reduce the dynamic math model created in
Workshop 1, using static reduction. Then find the first five natural
frequencies and mode shapes using the Automatic Givens method.
Use the points indicated in Figure 2.2 for the A-set.
Figure 2.1 – Grid Coordinates and Element Connectivities
Workshop 2 – Modal Analysis of a Flat Plate Using Static Reduction
a
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 input
1. Reference a previously created dynamic math model, plate.bdf, by
using the INCLUDE statement.
2. Prepare the model for a normal modes analysis (SOL 103 and
PARAMs).
PARAM, WTMASS, 0.00259
PARAM, COUPMASS, 1
3. Define degrees of freedom in the analysis set (ASET) for grids indicated
in Figure 2.2.
4. Generate an input file.
5. Go to step 5 under MSC.Patran users.
Workshop 2 – Modal Analysis of a Flat Plate Using Static Reduction
3 0 5 5 7 9 0 3 0 5 5 7 9 0 ID SEMINAR, PROB2 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ CEND _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ BEGIN BULKWorkshop 2 – Modal Analysis of a Flat Plate Using Static Reduction
Workshop 2 – Modal Analysis of a Flat Plate Using Static Reduction
1 2 3 4 5 6 7 8 9 10
Workshop 2: Modal Analysis of a Flat Plate Using Static Reduction
MSC.Nastran Users should go to Step 5
MSC.Nastran Users should go to Step 5
MSC.Patran Users
1. 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.
a. File / New.
b. Enter prob2 as the file name.
c. Click OK.
d. Choose Default Tolerance.
e. Select MSC.Nastran as the Analysis Code. f. Select Structural as
the Analysis Type. g. Click OK.
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
f
g
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:
ASET1,345,3,5,7,9,11 ASET1,345,25,27,29,31,33 ASET1,345,47,49,51,53,55
c. Click OK.
Step 4: Create the New Analysis Deck (cont.)
a
b
Step 4: Create the New Analysis Deck (cont.)
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
Step 4: Create the New Analysis Deck (cont.)
a. Click on Output Requests… b. Under Output Requests, highlight SPCFORCES(SORT1, REAL)=ALL FEM c. Click on Delete. d. Click OK. e. Click Apply. f. Click Cancel. g. Click Apply.a
e
f
d
b
c
g
Step 4: Create the New Analysis Deck (cont.)
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.
Step 5: Review Input File for MSC.Nastran Users
ID SEMINAR, PROB2 SOL 103
TIME 10 CEND
TITLE = REDUCTION PROCEDURES, NORMAL MODES EXAMPLE SUBTITLE = USING STATIC REDUCTION
ECHO = UNSORTED SUBCASE 1 SUBTITLE=USING LANCZOS METHOD = 1 SPC = 1 VECTOR=ALL BEGIN BULK EIGR,1,AGIV,,,,5 PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 INCLUDE ’plate.bdf’ $
$ SELECT A-SET, STATIC REDUCTION IS DONE AUTOMATICALLY $
ASET1,345,3,5,7,9,11 ASET1,345,25,27,29,31,33 ASET1,345,47,49,51,53,55 ENDDATA
For MSC.Nastran users who created the input file using a text
editor, the input file (prob2.dat) should be similar to the file below:
Step 6: Submitting the Input File for Analysis
Submit the input file to MSC.Nastran for analysis
Double click on MSC.Nastran icon.
Select prob2.bdf or prob2.dat and click Open.
Enter scr=yes in the Optional Keywords field.
Click Run.
Step 6: Submitting the Input File for Analysis
Submit the input file to MSC.Nastran for analysis
To submit the MSC.Nastran .bdf file for analysis, find an available
UNIX shell window. At the command prompt enter: nastran
prob2.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 prob2
scr=yes. Monitor the run using the UNIX ps command.
Step 7: Review F06 File
When the run is completed, edit the prob2.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 prob2.f06, search for the word R E A L (spaces
are necessary)
1st = __________Hz
2nd = __________Hz
3rd = __________Hz
4th = __________Hz
5th = __________Hz
Compare the results obtained in the .f06 file with the
following results:
Step 7: Review F06 File (cont.)
MSC.Nastran Users have finished this workshop.
MSC.Nastran Users have finished this workshop.
MSC.Patran Users should proceed to the next step.
Step 8: Attach XDB
Proceed with the Reverse Translation process, that is attaching the prob.xdb results file into
MSC.Patran. To do this, return to the Analysis form and proceed as follows. a. Analysis: Attach Results
/ Attach XDB / Result Entities.
b. Click Select Results
File.
c. Select prob2.xdb. d. Click OK.
e. Click Apply.
f. Turn off entity labels
g. Select Iso 3 view.
b
a
c
d
e
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
WORKSHOP 3
DIRECT TRANSIENT RESPONSE
ANALYSIS
Objectives
Define time-varying excitation.
Produce a MSC.Nastran input file from dynamic math model
created in Workshop 1.
Submit file for analysis in MSC.Nastran.
Compute nodal displacements for desired time domain.
Problem Description
Using 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 1
psi pressure load over the total surface of the plate varying at
250Hz. In addition, a 50 lb force is applied at a corner of the tip
also varying at 250Hz but out-of-phase with the pressure load.
Both time dependent dynamic loads are applied for the duration
of 0.008 seconds only. Use structural damping of g=0.06 and
convert this damping to equivalent viscous damping at 250Hz.
Carry the analysis for 0.04 seconds.
Workshop 3 – Direct Transient Response Analysis
Figure 3.1 Loads and Boundary Conditions
1 psi over the total surface
MSC.Nastran Users - Generate a MSC.Nastran input
file using a text editor
1. Reference previously created dynamic math model, plate.bdf, by using the
INCLUDE statement.
2. Define the time-varying pressure loading (PLOAD2, LSEQ and TLOAD2).
(Hint, be certain to specify phase angle since the applied loads are
out-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.
z
PARAM, G, 0.06
z
PARAM, W3, 1571.0
7. Request response in terms of nodal displacement at grid points 11, 33, and 55.
8. Generate an input file and submit it to the MSC.Nastran solver for direct
transient analysis.
9. Review the results, specifically the nodal displacements and xy-plot output.
ID SEMINAR, PROB3 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ 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 Users
1.
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 7
MSC.Nastran Users should go to step 7
Step 1. Create New Database
Create a new database named
prob3.db.
a. File / New.
b. Enter prob3 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. 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
a
c
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_pressure for the Field Name.
c. Click [Options…].
d. Enter 21 for Maximum Value of t. e. Click OK.
a
b
c
e
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
g
i
j
Step 4. Create Time Dependent Fields (cont.)
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
Step 4. Create Time Dependent Fields (cont.)
Create another time-dependent field for the transient response of the nodal force.
a. Fields: Create / Non Spatial / Tabular Input
b. Enter time_dependent_force for the Field Name.
c. Click [Options…].
d. Enter 21 for Maximum Value of t. e. Click OK.
a
b
c
e
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
g
i
j
Step 4. Create Time Dependent Fields (cont.)
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
Step 5. Create Load/Boundary Conditions
Create the time-dependent pressure load.
a. Loads/BCs: Create / Pressure / Element Uniform.
b. Enter pressure for the New Set Name. c. Change the Target Element Type to 2D. d. Click on the Input
Data button.
e. Enter -1 for Top Surf Pressure, and select
time_dependent_pre ssure for the
Time/Freq. Dependent Field. f. Click OK. g. Click on Select Application Region. h. Choose FEM i. Select all the
elements for the application region. j. Click Add, and click
OK. k. Click Apply.
a
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_for ce for the Time/Freq.
Dependent Field. e. Click OK.
f. Click on Select
Application Region.
g. Change the Geometry Filter to FEM.
h. Select Node 11 on the bottom right corner of the plate. i. Click Add, and click
OK. j. Click Apply.
a
b
c
d
e
f
g
h
i
j
i
d
Step 5. Create Load/Boundary Conditions (cont.)
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
Generate the input file for analysis. a. Analysis: Analyze / Entire
Model / Analysis Deck. b. Enter prob3 as the Job
Name.
c. Click Translation
Parameters.
d. Check XDB and Print. e. Click OK.
d
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
c
d
e
f
g
h
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Click on Subcases. b. Select
transient_response
from the Available Subcases field. c. Click on Subcase
Parameters.
d. Click on DEFINE TIME
STEPS button. e. Change Delta-T to 0.0004. Click Enter. f. Click OK. g. Click OK.
a
c
b
d
e
f
g
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Click on Output
Requests.
b. Change Form Type to
Advanced.
c. Under Output Requests, select
SPCFORCES(SORT2, REAL)=All FEM and
click Delete. d. Select
DISPLACEMENT(SOR T2,REAL)=All FEM and
select By Freq/Time under Options: Sorting. e. Click OK. f. Click Apply. g. Click Cancel.
a
b
c
d
e
c
d
f
g
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Click on Subcase Select. b. Select transient_response and unselect Default. c. Click OK. d. Click Apply.
a
b
c
d
b
An MSC.Nastran input file called prob3.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.
Step 7: Review Input File for MSC.Nastran Users
D SEMINAR, PROB3 SOL 109
TIME 30 CEND
TITLE= TRANSIENT RESPONSE WITH TIME DEPENDENT PRESSURE AND POINT LOADS
SUBTITLE= USE THE DIRECT METHOD ECHO= PUNCH
SPC= 1
SET 1= 11, 33, 55 DISPLACEMENT= 1 SUBCASE 1
DLOAD= 700 $ SELECT TEMPORAL COMPONENT OF TRANSIENT LOADING
LOADSET= 100 $ SELECT SPACIAL DISTRIBUTION OF TRANSIENT LOADING
TSTEP= 100 $ SELECT INTEGRATION TIME STEPS $
OUTPUT (XYPLOT) XGRID=YES YGRID=YES
XTITLE= TIME (SEC)
YTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER XYPLOT DISP RESPONSE / 11 (T3)
YTITLE= DISPLACEMENT RESPONSE AT CENTER TIP XYPLOT DISP RESPONSE / 33 (T3)
YTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER XYPLOT DISP RESPONSE / 55 (T3)
$
BEGIN BULK
PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259 $
$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE $
For MSC.Nastran users who created the input file using a text
editor, the input file (prob3.dat) should be similar to the file below:
INCLUDE ’plate.bdf’ $
$ SPECIFY STRUCTURAL DAMPING
$ 3 PERCENT AT 250 HZ. = 1571 RAD/SEC. $
PARAM, G, 0.06 PARAM, W3, 1571. $
$ APPLY UNIT PRESSURE LOAD TO PLATE $
LSEQ, 100, 300, 400 $
PLOAD2, 400, 1., 1, THRU, 40 $
$ VARY PRESSURE LOAD (250 HZ) $
TLOAD2, 200, 300, , 0, 0., 8.E-3, 250., -90. $
$ APPLY POINT LOAD OUT OF PHASE WITH PRESSURE LOAD $ TLOAD2, 500, 600, , 0, 0., 8.E-3, 250., 90. $ DAREA, 600, 11, 3, 1. $ $ COMBINE LOADS $ DLOAD, 700, 1., 1., 200, 50., 500 $
$ SPECIFY INTERGRATION TIME STEPS $
TSTEP, 100, 100, 4.0E-4, 1 $
Step 8: Submit Input File for Analysis
Submit the input file to MSC.Nastran for analysis
Double click on MSC.Nastran icon.
Select prob3.bdf or prob3.dat and click Open.
Enter scr=yes in the Optional Keywords field.
Click Run.
Step 8: Submit Input File for Analysis (cont.)
Submit the input file to MSC.Nastran for analysis
To submit the MSC.Nastran .bdf file for analysis, find an available
UNIX shell window. At the command prompt enter: nastran
prob3.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 prob3
scr=yes. Monitor the run using the UNIX ps command.
Step 9: Review F06 File
MSC.Nastran users use plotps utility to create a postscript file,
prob3.ps, from the binary plot file, Prob3.plt.
When the run is completed, edit the prob3.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 prob3.f06, search for the word D I S P L (spaces
are necessary)
Displacement at Grid 11
Time T3
.0024 = ___________
.0052 = ___________
.02 = ___________
Step 9: Review F06 File (cont.)
Displacement at Grid 33
Time T3
.0024 = ___________
.0052 = ___________
.02 = ___________
Displacement at Grid 55
Time T3
.0024 = ___________
.0052 = ___________
.02 = ___________
Step 9: Review F06 File (cont.)
Compare the results obtained in the .f06 file with the
Step 9: Review F06 File (cont.)
MSC.Nastran Users have finished this workshop.
MSC.Nastran Users have finished this workshop.
MSC.Patran Users should proceed to the next step.
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
Step 11. View Results
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 othernodes, simply select them and click
Step 11. View Results (cont.)
Displacement Response at Node 11
Step 11. View Results (cont.)
Step 11. View Results (cont.)
WORKSHOP 4
MODAL TRANSIENT RESPONSE
ANALYSIS
Objectives
Define time-varying excitation.
Produce a MSC.Nastran input file from dynamic math model
created in Workshop 1.
Submit file for analysis in MSC.Nastran.
Compute nodal displacements for desired time domain.
Problem Description
Using 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 1
psi pressure load over the total surface of the plate varying at
250Hz. In addition, a 25 lb force is applied at a corner of the tip
also varying at 250Hz but starting .0004 seconds after the
pressure load begins. Both time dependent dynamic loads are
applied for the duration of 0.008 seconds only. Use structural
damping of g=0.03 and convert this damping to equivalent
viscous damping at 250Hz. Carry the analysis for 0.04
seconds.
Workshop 4 – Modal Transient Response Analysis
Figure 3.1 Loads and Boundary Conditions
1 psi over the total surface
MSC.Nastran Users - Generate a MSC.Nastran input
file using a text editor
1. Reference previously created dynamic math model, plate.bdf, by using the
INCLUDE statement.
2. Specify modal damping as a tabular function of natural frequency (TABDMP1).
3. Define the time-varying tip load (DAREA and TLOAD2).
4. Combine the time-varying loads (DLOAD).
5. Specify integration time steps (TSTEP).
6. Prepare model for a modal transient analysis (SOL 112).
7. Request response in terms of nodal displacement at grid 11, 33, and 55.
8. Generate an input file and submit it to the MSC.Nastran solver for normal
modes analysis.
9. Review the results, specifically the nodal displacements.
ID SEMINAR, PROB4 _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ 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 Users
1.
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 7
MSC.Nastran Users should go to step 7
Step 1. Create New Database
Create a new database named
prob4.db.
a. File / New.
b. Enter prob4 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. 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
a
c
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_pressure for the Field Name.
c. Click [Options…].
d. Enter 21 for Maximum Value of t. e. Click OK.
a
b
c
e
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
g
i
j
Step 4. Create Time Dependent Fields (cont.)
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
Step 4. Create Time Dependent Fields (cont.)
Create another time-dependent field for the transient response of the nodal force.
a. Fields: Create / Non Spatial / Tabular Input
b. Enter time_dependent_force for the Field Name.
c. Click [Options…].
d. Enter 32 for Maximum Value of t. e. Click OK.
a
b
c
e
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
g
i
j
Step 4. Create Time Dependent Fields (cont.)
k. For row 32 in the table, enter 0.04 for
Time(t) and 0.0 for Value. l. Click OK. m. Click Apply.
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_pre ssure for the
Time/Freq. Dependent Field. f. Click OK. g. Click on Select Application Region. h. Choose FEM i. Select all the
elements for the application region. j. Click Add, and click
OK. k. Click Apply.
a
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 <0,0,25> for Force, and select
time_dependent_for ce for the Time/Freq.
Dependent Field. e. Click OK.
f. Click on Select
Application Region.
g. Change the Geometry Filter to FEM.
h. Select Node 11 on the bottom right corner of the plate. i. Click Add, and click
OK. j. Click Apply.
a
b
c
d
e
f
g
h
i
j
i
d
Step 5. Create Load/Boundary Conditions (cont.)
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
Generate the input file for analysis. a. Analysis: Analyze / Entire
Model / Analysis Deck. b. Enter prob4 as the Job
Name.
c. Click Translation
Parameters.
d. Check XDB and Print. e. Click OK.
d
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 Modal.
d. Click on Solution
Parameters.
e. Change the Mass Calculation to Coupled. f. Enter 0.00259 for Wt-Mass Conversion.
a
b
c
d
e
f
i
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Click on Eigenvalue
Extraction.
b. Set the Number of Desired Roots to 5. c. Click OK. d. Click OK. e. Click OK.
b
c
d
a
e
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Click on Subcases. b. Select
transient_response
from the Available Subcases field. c. Click on Subcase
Parameters.
d. Click on DEFINE TIME
STEPS button. e. Change Delta-T to 0.0004. Click Enter. f. Click OK.
a
c
b
d
e
f
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Set Modal Damping to
Crit. Damp. (CRIT).
b. Click on DEFINE
MODAL DAMPING
button.
c. Click Add Row.
d. Enter 0 and 10 for the Frequency, and 0.03 for both values. e. Click OK. f. Click OK.
a
b
d
c
e
f
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Click on Output
Requests.
b. Change Form Type to
Advanced.
c. Under Output Requests, select
SPCFORCES(SORT2, REAL)=All FEM and
click Delete. d. Select
DISPLACEMENT(SOR T2,REAL)=All FEM and
select By Freq/Time under Options: Sorting. e. Click OK. f. Click Apply. g. Click Cancel.
a
b
c
d
e
c
d
f
g
Step 6. Create Input File (cont.)
Generate the input file for analysis (cont.).
a. Click on Subcase Select. b. Select transient_response and unselect Default. c. Click OK. d. Click Apply.
