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SECTION COMPOSITE MATERIALS

SECTION COMPOSITE MATERIALS. COMPOSITE MATERIALS. Classical Lamination Theory Composite Material Definition QUAD4 and TRIA3 elements Ply Data Recovery Composite Failure Theorems Post Processing Not Supported in MSC.PATRAN. Ply Definition.

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SECTION COMPOSITE MATERIALS

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  1. SECTION COMPOSITE MATERIALS

  2. COMPOSITE MATERIALS • Classical Lamination Theory • Composite Material Definition • QUAD4 and TRIA3 elements • Ply Data Recovery • Composite Failure Theorems Post Processing Not Supported in MSC.PATRAN

  3. Ply Definition • Typically a ply is a flat group of fibers imbedded in a matrix. • The matrix is usually an isotropic material that holds the fibers together. • In a ply called a tape, the fibers are unidirectional. • In a ply called a cloth, the fibers are woven at 0 and 90 degree directions.

  4. Tape Plies • Fiber: • Unidirectional in tape • direction is the 1 axis of the ply coordinate system • Matrix: • glue that holds fibers together • matrix direction is the 2 axis • 90 degrees to the 1 axis • Material properties are: • 2D orthotropic material in Patran • MAT8 in Nastran

  5. MAT8 bulk data entry • Defines the ply orthotropic properties. • Elastic properties are E1, E2, NU12, G12, G1Z, G2Z. • Allowables are Xt, Xc, Yt, Yc, S. • Use STRN if allowables are in units of strain. • F12 is for the Tsai-Wu failure theorem. • Thermal coefficients of expansion are A1 and A2, • initial temperature is TREF, • density is RHO, • damping is GE. • The example below is typical for a graphite/epoxy tape. .bdf file extract mat8, 1, 20.+6, 2.+6, 0.35, 1.5+6, 1.6+6, 1.4+6, 1.3-4,+ +, -2.3-7, 4.5-6,, 1.1+5, 1.05+5, 1.2+4, 1.5+4, 2.+4

  6. Patran 2D Orthotropic Materials: Create/ 2d Orthotropic/ Manual Input Material Name Input Properties Linear Elastic Apply Input Properties Failure Apply

  7. Composite Material • Stack of plies • Each ply has a different direction, material, and thickness • Composite properties are calculated in the material coordinate system (Xm, Ym, Zm) • Zm is the same as the element Z axis (Ze) • Xm is either an angle relative to element G1G2 vector or is the projection of the X axis of a defined coordinate system • Positive angles are defined by right hand rule around Zm

  8. PCOMP bulk data entry • Defines the composite layup. • The example composite below is an 8 ply layup, symmetric about it’s centerline, with an equal number of plies is each of the 0, +-45, 90 degree directions. .bdf file extract pcomp,1,,,5000.0,hill,,,,+ +,1,.0054, 0.0,yes,1,.0054, 45.,yes,+ +,1,.0054,-45.,yes,1,.0054, 90.,yes,+ +,1,.0054, 90.,yes,1,.0054,-45.,yes,+ +,1,.0054, 45.,yes,1,.0054, 0.0,yes

  9. Patran Composite Materials: Create/ Composite/ Laminate Click on tape property name for each of the plies Thickness for all layers: .0054<cr> Orientations: 0 45 –45 90 90 –45 45 0 Load Text Into Spreadsheet Apply

  10. CQUAD4 bulk data entry • Defines the composite plate. • Material coordinate system can be defined one of two ways: • MCID – (integer) - ID of a user defined coordinate system who’s X-axis is projected onto the element to define the element’s material coordinate system’s X-axis. This along with the Z-axis of the element coordinate system defines the material coordinate system. • THETA – (real) - an angle between the G1G2 vector of the element and the X-axis of the material coordinate system. The positive sense of this angle is the right hand rule direction around the element’s Z-axis. cquad4,1,1,1,2,3,4,99 cquad4,1,1,1,2,3,4,25.0

  11. Patran Composite Properties Properties: Create/ 2D/ Shell Option: Laminate Input Properties Click on composite material name Click on coord. sys. for projection to material coord. sys. OK Select elements Apply

  12. Patran Material Coord. Z-axis Elements: Verify/ Element/ Normals Draw Normal Vectors Apply

  13. Patran Material Coord. X-axis Properties: Show/ Shell Orientation Angle Apply

  14. Patran Ply Output Request Analysis: Analyze/ Entire Model/ Full Run Subcases/ Create Output Requests/ Advanced/ Element Stress Ply Stresses OK Apply

  15. Patran Ply Stress Results Attach xdb: Results: Create/ Quick Plot Result/ Stress Tensor Position/ Layer 1 Quantity/ X Component Apply

  16. Composite Failure Indices • Hoffman: • Hill: • Tsai-Wu: s1, s2, t12 are ply stresses from the Nastran analysis X, Y, S are ply stress allowables from the PCOMP bulk data entry F12 is experimentally determined

  17. Composite Failure Indices e1, e2, g12 are ply strains from the Nastran analysis X, Y, S are ply strain allowables from the PCOMP bulk data entry (set STRN term on PCOMP to 1.0) • Max Strain: • Three failure indices • One for each direction • Uses strain allowables • Max Stress: • Same as Max Strain but allowables are in stress units s1, s2, t12 are ply stresses from the Nastran analysis X, Y, S are ply stress allowables from the PCOMP bulk data entry

  18. Nastran Failure Index Output F A I L U R E I N D I C E S F O R L A Y E R E D C O M P O S I T E E L E M E N T S ( Q U A D 4 ) ELEMENT FAILURE PLY FP=FAILURE INDEX FOR PLY FB=FAILURE INDEX FOR BONDING FAILURE INDEX FOR ELEMENT FLAG ID THEORY ID (DIRECT STRESSES/STRAINS) (INTER-LAMINAR STRESSES) MAX OF FP,FB FOR ALL PLIES 1 HILL 1 6.6183 0.1776 2 4.1766 0.1822 3 14.5333 0.0315 4 20.0144 20.0144 *** 2 HILL 1 1.8251 0.1288 2 0.9096 0.1322 3 4.0140 0.0228 4 9.5973 9.5973 *** 3 HILL 1 6.0914 0.1912 2 8.4410 0.1961 3 7.4905 0.0339 4 10.2642 10.2642 *** 4 HILL 1 0.0641 0.1153 2 0.8806 0.1183 3 8.7623 0.0204 4 19.9326 19.9326 *** • Printed in the f06 file if allowbles on PCOMP bulk data entry are present. • Failure index display not supported in Patran. .f06 file extract

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