XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX''"> 11.9 Frequency Response Setup Using Patran Interface
Create Unit Input Field.
• Click on Field.
• Create Non-Spatial Field
• Specify Unit value (1.0) from 0.1 to 2000 Hz
Frequency Response Setup - Patran Interface(Contd)
Create Time/Frequency Dependent Load Cases
• Select Load Cases
• Action: Create
• Load Case Name: Pressure_Loadcase
• Change Type to “Time Dependent”
• Apply
Repeat the procedure to create Load Case: Force_Loadcase
Frequency Response Setup - Patran Interface(Contd)
Create Loads
• Click on Load/BC
• Create Pressure. Set Current Load Case to Pressure_Loadcase
• Click on Input Data and applied unit pressure
• Click on Time-Freq Dependence Colun and select Unit-Field
• Apply
• Change Current Load case to Force_Loadcase and repeat procedure for Unit Force at tip
Frequency Response Setup - Patran Interface(Contd)
Select Analysis from Main Menu
• Assign Job Name: Freq-Plate
• Click on Solution Type
• Select Frequency Response
• Click on Solution Parameter (see next page)
Frequency Response Setup - Patran Interface(Contd)
• In Solution Parameter Form Click on Eigenvalue Extraction
• Select Lower and Upper bound frequency range
• Clear the default value of “Number of Desired Root”
• Click OK on both forms
• Return to Main Analysis Form
Frequency Response Setup - Patran Interface(Contd)
• On main Analysis Form, Click on “Subcases..”
Repeat following procedure for both subcases
• On Subcases Form, Select “Pressure Load Case” in “Available Subcases
• Click on Subcase Parameter (see next page)
Frequency Response Setup - Patran Interface (Contd)
• On Subcase Parameter form, Click on Define Frequencies.
• Specify all solution (output) frequencies. Make sure to define same output frequencies for all subcases.
• Change Modal Damping to “Crit. Damp (CRIT)”
• Specify 2% Damping from 0.1 to 2000 Hz
• Click OK on all forms and return Subcases Form and click on “Output Request” (see Next Page)
Frequency Response Setup - Patran Interface(Contd)
• On Subcases Form, Click on Output Request
• Change Form Type to Advanced
• Select all output desired. If printed output is not desired, click on “Supress Print for Request Type”
• For Strain Output, make sure to select either “plane-curv” or “fiber”
In MSC Random Interface, same set of output frequencies, damping, output request, applies to all load cases, whereas in Patran Interface, output request, output frequency list, and damping need to be specified for all load cases – even if they are same.
Repeat All option on “Subcase Form” for second subcase, Force_Loadcase..
i.e. Output Frequencies, Damping (subcase parameter form) and all output requests.
Frequency Response Setup - Patran Interface(Contd)
• Return to main Analysis Form
• Click on Subcase Select
• On Subcase Select, Make sure subcases are selected in the order. i.e. Pressure_Loadcase is first and then Force_Loadcase. This is required since Random Input will refer to Subcase 1 as Pressure Load.
• Click OK and return to main form
• Click Apply. MSC Nastran input file “freq-plate” will be created. See partial listing of input on next page.
Partial Input List of “freq-plate.bdf”
SOL 111
CEND
SUBTITLE = freq-resp created using Patran
ECHO = NONE
LOADSET = 1
SDAMPING = 1
SUBCASE 1
TITLE=Unit-Pressure
METHOD = 1
FREQUENCY = 1
SPC = 2
DLOAD = 2
DISPLACEMENT(SORT1,REAL)=ALL
STRAIN(SORT1,REAL,VONMISES,FIBER,CUBIC)=ALL
STRESS(SORT1,REAL,VONMISES,CUBIC)=ALL
SUBCASE 2
TITLE=Applied-unit-force
METHOD = 1
FREQUENCY = 2
SPC = 2
DLOAD = 4
ACCELERATION(PLOT,SORT1,REAL)=ALL
SPCFORCES(SORT1,REAL)=ALL
STRAIN(PLOT,SORT1,REAL,VONMISES,FIBER,BILIN)=ALL
STRESS(PLOT,SORT1,REAL,VONMISES,BILIN)=ALL
BEGIN BULK
PARAM POST 0
PARAM WTMASS .002589
PARAM PRTMAXIM YES
FREQ2 1 10. 1000. 300
FREQ4 1 10. 1000. .1 3
FREQ 1 20. 30. 100. 500.
TABDMP1 1 CRIT
.1 .02 2000. .02 ENDT
FREQ2 2 10. 1000. 300
FREQ4 2 10. 1000. .1 3
FREQ 2 20. 30. 100. 500.
EIGRL 1 2000. 0
$ Grid, Element, properties, materials data deleted
$ Loads for Load Case : Pressure_Loadcase
SPCADD 2 3
RLOAD1 6 7 1
LSEQ 1 7 3
DLOAD 2 1. 1. 6
$ Displacement Constraints of Load Set : Left-Edge-SPC
SPC1 3 123456 1 12 23 34 45
$ Loads for Load Case : Force_Loadcase
RLOAD1 8 9 1
LSEQ 1 9 5
DLOAD 4 1. 1. 8
$ Nodal Forces of Load Set : force
FORCE 5 11 0 1. 0. 0. 1.
$ Pressure Loads of Load Set : Pressure
PLOAD4 3 1 -1. THRU 40
$ Referenced Dynamic Load Tables
$ Dynamic Load Table : Unit-Field
TABLED1 1
.1 1. 2000. 1. ENDT
……………
ENDDATA
7.
