WS7-1 WORKSHOP 7 DIRECT TRANSIENT RESPONSE WITH ENFORCED ACCELERATION LARGE MASS METHOD NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation

WS7-2 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation

WS7-3 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation DIRECT TRANSIENT RESPONSE WITH ENFORCED ACCELERATION n Problem Description u Using the Direct Method, determine the transient response due to a unit acceleration sine pulse of 250 Hz applied at the base in the Z- direction. A large mass of 1000 lb is applied to the base. Use a structural damping coefficient of g = 0.06 and convert this damping to equivalent viscous damping at 250 Hz. u Below is a finite element representation of the flat plate. It also contains the loads and boundary constraints lbs mass

WS7-4 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation DIRECT TRANSIENT RESPONSE WITH ENFORCED ACCELERATION n Suggested Exercise Steps 1. Import the model from Workshop 1a. 2. Create a non-spatial field for the force load. 3. Create a time 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 1000 pound mass to the point element. 7. Create the time dependent force load. 8. Modify the original constraint from the imported database. 9. Submit the model to MSC.Nastran for analysis. 10. Attach the.XDB results file. 11. Post Process results – create X vs Y graph of displacements and accelerations.

WS7-5 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation CREATE NEW DATABASE Create a new database called ws7.db. a.File / New. b.Enter ws7 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

WS7-6 NAS122, Workshop 7, 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

WS7-7 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation e f Step 2. Field: Create / Non Spatial / Tabular Input Create a Non Spatial field for the force load. a.Field: Create / Non Spatial / Tabular Input. b.Enter force field for the Field Name. c.Select Time(t) as the Active Independent Variable. d.Click Input Data. e.Click Map Function to Table. f.Type in the function, sind(250*360*t), and values shown. g.Click Apply. h.Enter 0.04 for Time and 0.0 for Value in Row 21. i.Click OK. j.Click Apply. a b c d g h i j

WS7-8 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 3. Load Cases: Create Create a Time Dependent load case. a.Load Cases: Create b.Enter transient 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

WS7-9 NAS122, Workshop 7, 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.Uncheck Associate with Geometry. c.Enter [0 1 –0.5] for the Node Location. d.Click Apply. e.Change the view angel to Iso2View. f.Create / Element / Edit. g.Change the Shape and Topology to Point. h.Select the node created in previous step as Node 1. i.Click Apply. a b c d e f g h i

WS7-10 NAS122, Workshop 7, 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.Create / MPC / RBE2. b.Click Define Terms. c.Select the 5 nodes on the left edge of the plate for the Dependent Nodes. d.Choose UZ as the DOF for the Dependent Nodes. e.Click Apply. f.Select the node associated to the Point Element as the Independent node. g.Click Apply. h.Click Cancel. i.Click Apply. a b g h i d c f e

WS7-11 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 6. Properties: Create / 0D / Mass Assign a 1000 pound mass to the Point Element. a.Properties: Create / 0D / Mass. b.Enter Mass as the Property Set Name. c.Change the option to Grounded. d.Click on Input Properties. e.Enter 1000 for the Mass. f.Using the pull down menu, select UZ as the DOF at Node 1. g.Click OK. h.Click in the Select Members box. i.Change the Entities selection option to Point Element and select the point element created earlier. j.Click Add. k.Click Apply. a b c d e f g h j k i

WS7-12 NAS122, Workshop 7, 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 force_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 the Node associated to the point element. i.Click Add, and click OK. j.Click Apply. a b c d e f g h i j i

WS7-13 NAS122, Workshop 7, 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. e.Click OK. f.Click Apply. a b c d e f

WS7-14 NAS122, Workshop 7, 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 Transient Response. d.Change the Formulation to Direct. e.Click on Solution Parameters button. f.Select Coupled for Mass Calculation. g.Enter for Wt-Mass Conversion. h.Enter 0.06 for the Struct. Damping Coeff. and 1571 for the W3 Damping Factor. i.Click OK. j.Click OK. a b c d e f h i g j

WS7-15 NAS122, Workshop 7, 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 transient from the Available Subcases field. c.Click on Subcase Parameters. d.Click on DEFINE TIME STEPS button. e.Enter 200 for the No. of Time Steps and for Delta-T. f.Click OK. g.Click OK. a b c d e f g

WS7-16 NAS122, Workshop 7, 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

WS7-17 NAS122, Workshop 7, 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 transient and unselect Default. c.Click OK. d.Click Apply. a b c d

WS7-18 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 10. 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 ws7.xdb. d.Click OK. e.Click Apply. a b c e d

WS7-19 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Results: Create / Graph / Y vs X Create a X-Y graph of displacement results. a.Results: Create / Graph / Y vs X. b.Click on TRANSIENT. c.Select Global Variable as the Filter Method. d.Click Filter. e.Click Apply. f.Click Close. a b c d e f

WS7-20 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 11. 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 associated to the Point Element. f.Click Apply. b a c d e f

WS7-21 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Results: Create / Graph / Y vs X (Cont.)

WS7-22 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Results: Create / Graph / Y vs X (Cont.) Create a X-Y graph of displacement results (cont.). nSelect the node in the middle of the opposite edge. nClick Apply. b a 33

WS7-23 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Results: Create / Graph / Y vs X (Cont.)

WS7-24 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Results: Create / Graph / Y vs X (Cont.) Create a X-Y graph of acceleration results. a.Click on Select Results. b.Select Accelerations, Translational from Select Y Result box. c.Click Apply. b a c

WS7-25 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation Step 11. Results: Create / Graph / Y vs X (Cont.)

WS7-26 NAS122, Workshop 7, August 2005 Copyright 2005 MSC.Software Corporation