WORKSHOP 2 FAILURE CRITERIA FOR FLAT PLATE WS2-1 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation

WS2-2 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation

WS2-3 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation Problem Description Use the model from the previous workshop. Modify the material properties to include a failure model. Information about how and when the material fails is needed for the margin of safety analysis. The following values can be used for the material properties Tension Stress Limit MPa Compress Stress Limit MPa Tension Stress Limit MPa Compress Stress Limit MPa Shear Stress Limit 68 MPa Interaction Term -0.5 Bonding Shear Stress 50 MPa Note that the interaction term, I xy, is non-dimensional, and needs to be converted to F12 for input into Patran, which uses the dimensional form.

WS2-4 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation Suggested Exercise Steps: 1. Create a new database. 2. Modify 2D orthotropic material to include failure model 3. Run MSC.Nastran to obtain failure indices 4. Read failure indices using MSC.Patran Utilities 5. Plot failure indices 6. Repeat Steps 2 – 5 using different failure theory 7. Modify the laminate to optimize strength/weight

WS2-5 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation a b c Open the last exercise database. a.File / Open. b.Select Flatplate as the file name. c.Click OK. Step 1. Create a New Database

WS2-6 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation Define constitutive failure model. a.Materials : Modify / 2d Orthotropic. b.Select ud_t300_n5208 from Existing Materials. c.Select Failure as the Constitutive Model. d.Select Tsai-Wu as the Composite Failure Theory. e.Enter 1500 as the Tension Stress Limit 11. f.Enter 40 as the Tension Stress Limit 22. g.Enter 1500 as the Compress Stress Limit 11. h.Enter 246 as the Compress Stress Limit 22. i.Enter 68 as the Shear Stress Limit. j.Enter –3.36e-6 as the Interaction Term. k.Enter 50 as the Bonding Shear Stress Limit. l.Click OK. m.Click Apply. Step 2. Modify 2D Orthotropic Material to Include Failure Model b a m 1500 d e f g h c l k j i

WS2-7 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation Run the analysis and retrieve the results. a.Analysis : Analyze / Entire Model / Full Run. b.Enter flatplate_2 as the Job Name. c.Click Apply. Step 3. Run MSC.Nastran to Obtain Failure Indices a b c In order to get the Failure Index, it is necessary to re-run the analysis using MSC.Nastran. The solver automatically detects that a failure analysis must be done if a failure criteria is defined for the material. Wait for the analysis to complete. The only way to retrieve Failure Criteria information from the results file is through a MSC.Patran Utility. This information cannot be obtained by linking to the.XDB results file.

WS2-8 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation a.Click Utilities. b.Select Results. c.Select Read MSC.N Failure Indices. d.Click OK. d c b a Step 4. Read Failure Indices Using MSC.Patran Utilities

WS2-9 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation a.Click F06 File:. b.Select flatplate_2.f06. c.Click OK. d.Enter Failure as the Loadcase Name. e.Click Apply. f.Click Cancel. a b c d e f Step 4. Read Failure Indices Using MSC.Patran Utilities (Cont.)

WS2-10 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation View Failure Results. a.Results : Create / Quick Plot. b.Select Failure, SUBCASE 1. c.Select Failure Indices, Ply Indices. d.Click Position…(Layer 1). e.Select Layer 1 through Layer 16. f.Select Maximum for Option. g.Click Close. h.Click Apply. Step 5. Plot Failure Indices a b c d h e f g

WS2-11 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation There is an overall Failure Index of , meaning that a substantial increase of the load can be allowed. (FI>1.0 indicates failure) However, the margin of safety is not known. Step 5. Plot Failure Indices (Cont.) This plot shows the deformation. As can be seen the maximum displacement is 164 mm. NOTE: This plot shows the highest Failure Index through all layers. This is a safe and quick way to get the overall results. Obviously, failure can be investigated on a layer-by-layer basis also.

WS2-12 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation Step 6. Repeat Steps 2 – 5 Using Different Failure Theory b a l d e f g h c k j i Define different constitutive failure model. a.Materials : Modify / 2d Orthotropic. b.Select ud_t300_n5208 from Existing Materials. c.Select Failure as the Constitutive Model. d.Select Maximum as the Composite Failure Theory. e.Enter 1500 as the Tension Stress Limit 11. f.Enter 40 as the Tension Stress Limit 22. g.Enter 1500 as the Compress Stress Limit 11. h.Enter 246 as the Compress Stress Limit 22. i.Enter 68 as the Shear Stress Limit. j.Enter 50 as the Bonding Shear Stress Limit. k.Click OK. l.Click Apply. Follow Step 2 – 5, including submitting model for analysis and retrieval of the.XDB file. Compare the result with the other result from using Tsai Wu as the composite failure theory.

WS2-13 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation Step 7. Modify the Laminate to Optimize Strength/Weight Modify the laminate. a.Materials : Modify / Composite / Laminate. b.Select My_first_laminate. c.Select row 16. d.Click Delete Selected Rows. e.Select row 15. f.Click Delete Selected Rows. g.Input 2(45 / 90 / 0 / 45 / 90 / 0 / 45) as the Insert Material Names. h.Select Overwrite as the Text Entry Mode. i.Elect Orientations. j.Click Load Text Into Spreadsheet. k.Click –Apply-. b a k Try modifying the model to optimise its strength, and at the same time reduce its weight. c f d e h i j g

WS2-14 PAT325, Workshop 2, February 2004 Copyright 2004 MSC.Software Corporation The deflection was reduced from 164 mm to 117 mm, and the weight was reduced by 12.5%. The Tsai-Wu failure Indices is still , meaning there is still have a good safety margin. Step 7. Modify the Laminate to Optimize Strength/Weight (Cont.)