Using the modal method, determine the transient response of the flat rectangular plate, created in Workshop 1, under
ID SEMINAR, PROB4
Workshop 4 – Modal Transient Response Analysis
1 2 3 4 5 6 7 8 9 10
Workshop 4 – Modal Transient Response Analysis
1 2 3 4 5 6 7 8 9 10
ENDDATA
Workshop 4 – Modal Transient Response Analysis
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
Workshop 4 – Modal Transient Response Analysis
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.
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
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
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
e c 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
i j g
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
e c 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
i j g
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
h. Choose FEM i. Select all the
elements for the application region.
j. Click Add, and click OK.
k. Click Apply.
a
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
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
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 Modal.
d. Click on Solution Parameters.
e. Change the Mass Calculation to Coupled.
f. Enter 0.00259 for Wt-Mass Conversion.
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.
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.
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
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 prob4.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 6. Create Input File (cont.)
Step 7: Review Input File for MSC.Nastran Users
ID SEMINAR, PROB4 SOL 112
TIME 30 CEND
TITLE = TRANSIENT RESPONSE WITH TIME DEPENDENT PRESSURE AND POINT LOADS
SUBTITLE = USE THE MODAL METHOD ECHO = UNSORTED
SPC = 1
SET 111 = 11, 33, 55 DISPLACEMENT(SORT2) = 111 SDAMPING = 100
SUBCASE 1 METHOD = 100 DLOAD = 700 LOADSET = 100 TSTEP = 100
$
OUTPUT (XYPLOT) XGRID=YES YGRID=YES
XTITLE= TIME (SEC)
YTITLE= DISPLACEMENT RESPONSE AT LOADED CORNER XYPLOT DISP RESPONSE / 11 (T3)
YTITLE= DISPLACEMENT RESPONSE AT TIP CENTER XYPLOT DISP RESPONSE / 33 (T3)
YTITLE= DISPLACEMENT RESPONSE AT OPPOSITE CORNER XYPLOT DISP RESPONSE / 55 (T3)
$
BEGIN BULK
PARAM, COUPMASS, 1 PARAM, WTMASS, 0.00259
$
$ PLATE MODEL DESCRIBED IN NORMAL MODES EXAMPLE PROBLEM
$
INCLUDE ’plate.bdf’