WS11-1 WORKSHOP 11 RANDOM VIBRATION ANALYSIS OF A SATELLITE MODEL USING MSC.RANDOM NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation

WS11-2 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation

WS11-3 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation RANDOM VIBRATION ANALYSIS ON A SATELLITE n Problem Description u The purpose of this workshop is to use MSC.Random to perform a Random Vibration analysis. In this workshop, a satellite model is used and a PSD input field is given. The user will first perform a Modal Frequency Response analysis and execute a Random analysis in MSC.Random using the results from the Frequency Response analysis.

WS11-4 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation PRESTIFFENED NORMAL MODES ANALYSIS n Suggested Exercise Steps 1. Import a Nastran Input File that contains the representation of the satellite model. 2. Create a Frequency Dependent field of magnitude 1.0 over a frequency range of 1.0 Hz to Hz. 3. Create two load cases called vertical acceleration and lateral acceleration. 4. Apply the field created in Step 2 to the bottom of the satellite to create a unit acceleration load. 5. Submit the model to MSC.Nastran for analysis. 6. Create the Frequency Dependent field that contains the PSD Input information. 7. Open MSC.Random. 8. Select the XDB Result Files from the Frequency Response analysis and perform Random Vibration analysis using MSC.Random 9. Post Process results – Use MSC.Random to create Acceleration versus Frequency plots at various location.

WS11-5 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation CREATE NEW DATABASE Create a new database called satellite.db. a.File / New. b.Enter satellite 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

WS11-6 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 1. File / Import Import the satellite.bdf file. a.File / Import. b.Select MSC.Nastran Input as the Source. c.Select satellite.bdf. d.Click Apply. e.Click OK when the Nastran Input File Import Summary appears. a b c d e

WS11-7 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 2. Field: Create / Non Spatial / Tabular Input Create a non spatial field for frequency response. a.Field: Create / Non Spatial / Tabular Input. b.Enter frequency response for the Field Name. c.Select Frequency as the Active Independent Variable. d.Click on Input Data button. e.Enter the values shown in the table. f.Click OK. g.Click Apply. a b c d e f g

WS11-8 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 3. Load Cases: Create Create a load case for the vertical acceleration load. a.Load Cases: Create. b.Enter vertical acceleration for the Load Case Name. c.Change Load Case Type to Time Dependent. d.Click on Assign/Prioritize Loads/BCs button. e.Select Displ_spc1.3 from the Select Individual Loads/BCs. f.Click OK. g.Click Apply. a b c d e f g

WS11-9 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 3. Load Cases: Create Create another load case for the lateral acceleration load. a.Load Cases: Create. b.Enter lateral acceleration for the Load Case Name. c.Click on Assign/Prioritize Loads/BCs button. d.Select Displ_spc1.1 from the Select Individual Loads/BCs. e.Click OK. f.Click Apply. a b c d e f

WS11-10 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 4. Loads/BCs: Create / Acceleration / Nodal Create the lateral acceleration load. a.Loads/BCs: Create / Acceleration / Nodal. b.Enter lateral acceleration for the New Set Name. c.Click on the Input Data button. d.Enter for Translations and select frequency_response for Time/Freq. Dependence field. e.Click OK. f.Click on Select Application Region. g.Change the Geometry Filter to FEM. h.Select the nodes along the bottom edge of the exhaust cone. i.Click Add, and click OK. j.Click Apply. a b c d e f g h i j i

WS11-11 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 4. Loads/BCs: Create / Acceleration / Nodal (Cont.)

WS11-12 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 4. Loads/BCs: Create / Acceleration / Nodal (Cont.) Create the vertical acceleration load. a.Click on the button indicating the Current Load Case. b.Select Vertical Acceleration and click OK. c.Enter vertical acceleration for the New Set Name. d.Click on the Input Data button. e.Enter for Translations and select frequency_response for Time/Freq. Dependence field. f.Click OK. g.Click on Select Application Region. h.Change the Geometry Filter to FEM. i.Select the nodes along the bottom edge of the exhaust cone. j.Click Add, and click OK. k.Click Apply. a b c d g h i j j e f k b

WS11-13 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 4. Loads/BCs: Create / Acceleration / Nodal (Cont.)

WS11-14 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run Submit the vertical acceleration load case for frequency response analysis. a.Analysis: Analyze / Entire Model / Full Run. b.Enter satellite_vertical_acc for the job name. c.Click on Solution Type. d.Select FREQUENCY RESPONSE and Modal Formulation. e.Click on Solution Parameters. f.Change the Wt-Mass Conversion to g.Click on Eigenvalue Extraction button. h.Change the Number of Desire Roots to 20. i.Click OK on all three sub- forms. a b c d i e f d g h i i

WS11-15 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the vertical acceleration load case to frequency response analysis. (cont.) a.Click on Subcases. b.Select vertical acceleration. c.Click on Subcase Parameters. d.Click on DEFINE FREQUENCIES. e.Enter the values shown in the table. f.Click OK. a b c d e f

WS11-16 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the vertical acceleration load case to frequency response analysis. (cont.) a.Select Crit. Damp. (CRIT) for Modal Damping. b.Click on DEFINE MODAL DAMPING. c.Enter the values shown in the table. d.Click OK on both forms. a b c d d

WS11-17 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the vertical acceleration load case to frequency response analysis. (cont.) a.Click on Output Requests. b.Select Acceleration from the Select Result Type box. c.Click OK. d.Click Apply. e.Click Cancel. a b c e d

WS11-18 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the vertical acceleration load case to frequency response analysis. (cont.) a.Click on Subcase Select. b.Select vertical acceleration from the top box and unselect Default from the Subcase Selected box. c.Click OK. d.Click Apply. a b c d

WS11-19 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the horizontal acceleration load case to MSC.Nastran for frequency response analysis. a.Click on the satellite_vertical_acc in the Available Jobs box. This will allow Patran to use same setting for the Solution Type as those used in the satellite_vertical_acc analysis. b.Change the Job Name to satellite_lateral_acc. c.Repeat the same procedures as per Page 15 through 17 for the Subcases setting, but choose the lateral acceleration subcases for this analysis job. d.Click on Subcase Select. e.Select lateral acceleration from Subcases For Solution Sequence box and unselect Default from the Subcases Selected box. f.Click OK. g.Click Apply. a b d e f g

WS11-20 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 6. Field: Create / Non Spatial / Tabular Input Create a non spatial field for the MSC.Random analysis. a.Enter psd for the Field Name. b.Select Frequency as the Active Independent Variable. c.Click on Input Data button. d.Enter the values shown in the table. e.Click OK. f.Click Apply. a b c d e f

WS11-21 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 7. Utilities / Applications / MSC.Random Open MSC.Random a.Utilities / Applications / MSC.Random. b.Click OK when the DISCLAIMER message appears on the screen. c.Change the Action from Freq. Response to RMS Analysis. a b c

WS11-22 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 8. Utilities / Applications / MSC.Random Setup the model for Random analysis. a.Click on Select XDB File. b.Select satellite_lateral_acc.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:LATERAL ACCELERATION from the Available Subcases box. g.Click on the Input Field and select psd from the PSD Input fields box. h.Click Close. i.Click Apply. a b c d e f g h i

WS11-23 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Utilities / Applications / MSC.Random Create XY Plots of the PSD Response. a.Change Action to XY Plots. b.Select Node 3326, which is where the PCB board will be located at. c.Change the Res. Type to Accel. d.Change Component to DOF 1. e.Change the Plot Type to PSDF. f.Click Apply. a b c d e f b

WS11-24 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Utilities / Applications / MSC.Random (Cont.) Setup the model for Random analysis. a.Change Action to RMS Analysis. b.Click on Select XDB File. c.Select satellite_vertical_acc.xdb, the results from the previous Frequency Response analysis. d.Click Apply. e.Select Random Input. f.Change the Random Input Method to Single Case. g.Click on the Excited Set field and select 1:VERTICAL ACCELERATION from the Available Subcases box. h.Click on the Input Field and select psd from the PSD Input fields box. i.Click Close. j.Click Apply. b c d e f g h i j a

WS11-25 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response. a.Change Action to XY Plots. b.Select Node 3326, which is where the PCB board will be located at. c.Change the Res. Type to Accel. d.Change Component to DOF 3. e.Change the Plot Type to PSDF. f.Click Apply. a b c d e f

WS11-26 NAS122, Workshop 11, August 2005 Copyright 2005 MSC.Software Corporation