The Poisson’s ratio (v13) result is generated from a Fiber orientation Pack analysis using 3D analysis technology.
The Poisson’s ratio (v13) result indicates the strain in the third principal direction caused by the stress in the first principal direction. In general, vij = Poisson’s ratio for transverse strain in the j-direction when stressed in the i-direction.
The thermo-mechanical property calculation for fiber-filled composites are based on the orthotropic assumption, that fiber-filled material properties are different in three orthogonal principal directions. Under this assumption, there are 9 independent mechanical constants and three independent thermal expansion coefficients.