Which theory is used to solve in Optistruct with PCOMPP

Hi,

according to Optistruct help (page 22):

Classical lamination theory is used to calculate effective stiffness and mass density of the composite shell. This is done automatically within the code using the properties of individual plies. The homogenized shell properties are then used in the analysis.

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Thank you very much Simon. 

Your answer leads me to another question. I did not know which theory was being used, so I tried to change the G1z and G2z (transverse shear modulus). The results of the analysis when those modulus were very low changed significantly. In the classical theory, isn't that not supposed to happen as the transverse deformations are not taken into account?

OptiStruct uses classical lamination theory to calculate effective stiffness and mass density of the composite shell.  This is done automatically within the code using the properties of individual plies.  

The composite inter-laminar stress is calculated based on the first-order shear deformation laminated plate theory.