I'm modeling a laminated composite surface in Nastran. In order to model the laminate, I need to define a 2D Orthotropic material (i.e. a fiber/matrix composite). Nastran's asking for E1, E2, G12, G1Z, G2Z, and nu12 (Poisson's). In all the calculations I'd done for fiber/matrix composites in the past, I've only needed E1, E2, G12, and nu12. For long, continuous aligned fiber composites, should I leave G1Z and G2Z as 0?
Thanks in advance! Dave
The requirement of G1Z and G2Z stem directly from the use of Mindlin plate theory with allowance for transverse shear. You can easily estimate them from a rule of mixtures, assuming the matrix and fiber fractions being parallel springs. As a result the G1Z and G2Z will be close to the G of the matrix material.
Timo
If you set them to 0 or leave them blank the transverse shear stiffness will be infinite (rigid) like a regular beam.
If you want to estimate values, then use something that's a fraction of G12 since the matrix material dominates in the off fiber directions.
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