WS5-1 WORKSHOP 5 DIRECT FREQUENCY RESPONSE ANALYSIS NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation

WS5-2 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation

WS5-3 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation DIRECT FREQUENCY RESPONSE ANALYSIS n Problem Description u Using the direct Method, determine the frequency response of the flat rectangular plate, created in Workshop 1a, subject to time- varying excitation. This example structure is excited by a unit load at a corner of the tip. Use a frequency step of 20 Hz between a range of 20 and 1000 Hz. Use structural damping of g = u Below is a finite element representation of the flat plate. It also contains the loads and boundary constraints.

WS5-4 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation DIRECT FREQUENCY RESPONSE ANALYSIS n Suggested Exercise Steps 1. Import the model from Workshop Create a non-spatial field for the pressure load. 3. Create a time dependent load case. 4. Create the time dependent force load. 5. Submit the model to MSC.Nastran for analysis. 6. Attach the.XDB results file. 7. Post Process results – create X vs Y graph of displacements.

WS5-5 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation CREATE NEW DATABASE Create a new database called ws5.db. a.File / New. b.Enter ws5 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

WS5-6 NAS122, Workshop 5, 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

WS5-7 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 2. Fields: Create / Non Spatial / Tabular Input Create a Non Spatial field for the pressure load. a.Fields: Create / Non Spatial / Tabular Input. b.Enter frequency_depend_load for the Field Name. c.Select Frequency (f) as the Active Independent Variable. d.Click Input Data. e.Enter the values shown in the table. f.Click OK. g.Click Apply. a b c d e f g

WS5-8 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 3. Load Cases: Create Create a Time Dependent load case. a.Load Cases: Create b.Enter direct_freq_response 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. b c d e f g a

WS5-9 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 4. Loads/BCs: Create / Force / Nodal Create the time dependent Force load. a.Loads/BCs: Create / Force / Nodal. b.Enter unit_load for the New Set Name. c.Click on the Input Data button. d.Enter for Force, and select frequency_depend_ load for the Time/Freq. Dependent Field. e.Click OK. f.Click on Select Application Region. g.Change the Geometry Filter to FEM. h.Select the bottom right corner node for the application region. i.Click Add, and click OK. j.Click Apply. a b c d e f g h i j i

WS5-10 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 5. 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 Direct. e.Click on Solution Parameter button. f.Enter for Wt- Mass Conversion. g.Enter 0.06 for Struct. Damping Coeff. h.Click OK. i.Click OK. a b c d e f g h i

WS5-11 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the model for analysis (cont.). a.Click on Subcases. b.Select direct_freq_response from the Available Subcases field. c.Click on Subcase Parameters. d.Click on DEFINE FREQUENCIES… button. e.Enter the data according to the table. f.Click OK. g.Click OK. h.Click Apply. i.Click Cancel. a b c f d g h i e

WS5-12 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 5. Analysis: Analyze / Entire Model / Full Run (Cont.) Submit the model for analysis (cont.). a.Click on Subcase Select. b.Select direct_freq_response and unselect Default. c.Click OK. d.Click Apply. a b c d

WS5-13 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 6. Analysis: Access Results / Attach XDB / Result Entities Attach the XDB result file. a.Analysis: Access Results / Attach XDB / Result Entities. b.Click on Select Results File. c.Select ws5.xdb. d.Click OK. e.Click Apply. a b c d e

WS5-14 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 7. Results: Create / Graph / Y vs X Create a X-Y graph of displacement results. a.Results: Create / Graph / Y vs X. b.Click on SC1:DIRECT_FREQ_RESP ONSE. c.Select Global Variable as the Filter Method. d.Click Filter. e.Click Apply. f.Click Close. a b c d e f

WS5-15 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 7. Results: Create / Graph / Y vs X (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 node where force is applied. f.Click Apply. b a c d e f

WS5-16 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 7. Results: Create / Graph / Y vs X (Cont.) Create a X-Y graph of displacement results (cont.). a.Click on Display Attribute. b.Change Y Axis Scale from Linear to Log. c.Click on Plot Option. d.Change the Complex No. as to Magnitude. e.Click Apply. b a c d e

WS5-17 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation Step 7. Results: Create / Graph / Y vs X (Cont.)

WS5-18 NAS122, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation