1. S-1PAT321, Section, June 2002 SECTION EQUIVALENT SECTION PROPERTIES FOR SANDWICH PLATES

2. S-2PAT321, Section, June 2002 Sandwich Plates n Sandwich plates are made of a top and bottom facesheet with a core between, which are all glued together. n This creates a plate that has a high bending stiffness for it’s weight. n The facesheets are usually thin plates of an isotropic material. n The core separates the facesheets and transmits shear loads between the facesheets but otherwise is usually considered to be structurally insignificant.

3. S-3PAT321, Section, June 2002 PSHELL bulk data entry n The PSHELL’s T, 12I/T**3, and TS/T fields are adjusted to account for the equivalent section. 12345678910 PSHELLPIDMID1TMID212I/T**3MID3TS/TNSM PSHELL 110.1115.010.55 pshell, 1, 1, 0.1, 1, 15.0, 1, 0.55,,+ +, 0.27, -0.27.bdf file extract Z1Z2MID4 0.27-0.27

4. S-4PAT321, Section, June 2002 n MID1, MID2, and MID3 all point to the same MAT1 isotropic material. n The T field on the PSHELL is set to the sum of the facesheet thicknesses (2*Tf). n The 12/T**3 field on the PSHELL is set to the ratio of the actual sandwich moment of inertia to the moment of inertia calculated from T on the PSHELL. In this case if the core moment of inertia is ignored: n An approximation for the effective shear thickness,Ts/T, is TS/T=(5/6)*(Tc+2Tf)/T Nastran Definitions of Sandwich Plates - PSHELL

5. S-5PAT321, Section, June 2002 Patran Equivalent Section Definition Materials: Create/ Isotropic/ Manual Input Enter Property Name Select Equivalent Section Option In Input Properties: Click on existing materials in the Material Property Sets box to enter Membrane (MID1), Bending (MID2), Shear (MID3) Materials Enter membrane Thickness (T) Enter Bending Stiffness ratio (12/T**3) Enter shear Thickness ratio (TS/T) Enter Fiber Dist. 1 and 2 stress recovery points (Z1 and Z2) OK Select Application Region Add Apply