WS9-1 WORKSHOP 9 RANDOM ANALYSIS USING MSC.RANDOM NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation

WS9-2 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation

WS9-3 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation n Problem Description u This workshop carries out a Random Response Analysis of the flat plate used through the cases, subject to the PSD acceleration input at the base. u 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. u 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

WS9-4 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation RANDOM RESPONSE n Suggested Exercise Steps 1. Import the model from Workshop 1a. 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.

WS9-5 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation CREATE NEW DATABASE Create a new database called ws9.db. a.File / New. b.Enter ws9 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

WS9-6 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 1. File / Import Import the model from Workshop 1a. a.File / Import. b.Select MSC.Patran DB as the Source. c.Select ws1a.db. d.Click Apply. e.Click OK when the Patran Database Import Summary appears. a b c d

WS9-7 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation e f Step 2. Field: Create / Non Spatial / Tabular Input Create a Non Spatial field for the load definition. a.Field: Create / Non Spatial / Tabular Input. b.Enter field for the Field Name. c.Select Frequency (f) as the Active Independent Variable. d.Click Input Data. e.Enter the data shown in the table. f.Click OK. g.Click Apply. a b c d g

WS9-8 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 3. Load Cases: Create Create a Frequency Dependent load case. a.Load Cases: Create b.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. f.Click OK. g.Click Apply. a c d e f g b

WS9-9 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation 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 c.Uncheck Associate with Geometry and Auto Execute. d.Enter [ ] 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 is checked. a b c e f g h i d

WS9-10 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Elements: Create / MPC / RBE2 Create a RBE2 to connect the Point element to the plate. a.Elements: Create / MPC / RBE2. 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 node created earlier as the Independent Node. g.Click Apply. h.Click Cancel. i.Click Apply. a b g h i c d e f

WS9-11 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation 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

WS9-12 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 7. Loads/BCs: Create / Force / Nodal Create the time dependent Force. a.Loads/BCs: Create / Force / Nodal. b.Enter force for the New Set Name. c.Click on the Input Data button. d.Enter for Force, and select field 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 i.Click Add, and click OK. j.Click Apply. a b c d e f g h i j i

WS9-13 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 8. Loads/BCs: Modify / Displacement / Nodal Modify the original constraint from the imported database. a.Loads/BCs: Modify / Displacement / Nodal. b.Click on constraint in the Select Set to Modify box to select it. c.Click on the Modify Data button. d.Modify the Translation to and Rotations to e.Click OK. f.Click Modify Application Region. g.Highlight all the data in the Application Region and delete them. h.Select Node i.Click Add and OK. j.Click Apply. a b c d e f h i j g i

WS9-14 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation 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 for Wt-Mass Conversion. h.Click OK. i.Click OK. a b c d e f h g i

WS9-15 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the model for analysis (cont.). a.Click on Subcases. b.Select random from the Available Subcases field. c.Click on Subcase Parameters. d.Click on DEFINE FREQUENCIES button. e.Enter the frequency data shown in the table. f.Click OK. a b c d e f

WS9-16 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the model for analysis (cont.). 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

WS9-17 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the model for analysis (cont.). a.Click on Output Requests. b.Select Accelerations in the Select Result Type box. c.Click OK. d.Click Apply. e.Click Cancel. a b c d e

WS9-18 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 9. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the model for analysis (cont.). a.Click on Subcase Select. b.Select random and unselect Default. c.Click OK. d.Click Apply. a b c d

WS9-19 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation e f Step 10. Field : Create / Non Spatial / Tabular Input Create a Non Spatial field for the Random Analysis. a.Field: Create / Non Spatial / Tabular Input. b.Enter Random for the Field Name. c.Select Frequency (f) as the Active Independent Variable. d.Click Input Data. e.Enter the data shown in the table. f.Click OK. g.Click Apply. a b c d g

WS9-20 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random Open MSC.Random to prepare for Random Analysis. a.Utilities / Applications / MSC.Random. b.Click OK when DISCLAIMER appears c.Select RMS Analysis. a c

WS9-21 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random (Cont.) Setup the model for Random analysis. a.Action: RMS Analysis. Click on Select XDB File. b.Select ws9.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 Field and select Random from the PSD Input fields box. h.Click Close. i.Click Apply. a b c d e f g h i a

WS9-22 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response. a.Change Action to XY Plots. b.Select Node 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

WS9-23 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a.Select the node at the tip center. b.Click Apply. a b

WS9-24 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a.Select the node at the tip corner. b.Click Apply. a b

WS9-25 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a.Change the Plot Type to CRMS. b.Click Apply. a b

WS9-26 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a.Select the node at the tip center. b.Click Apply. a b

WS9-27 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Utilities / Applications / MSC.Random (Cont.) Create XY Plots of the PSD Response (cont.). a.Select Node b.Click Apply. a b

WS9-28 NAS122, Workshop 9, August 2005 Copyright 2005 MSC.Software Corporation