The Poisson’s ratio (v12) result indicates the strain in the second 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.
This result is generated from a Fiber orientation Pack analysis.
For a Midplane and Dual Domain analysis, the Poisson’s ratio (v12) result is recorded for each laminate in the model over the duration of the analysis. Therefore, each laminate in the model will have different results. You can check the Poisson’s ratio in each laminate by animating the default contour plot, which will animate the result over the Normalized thickness.
For a 3D Fiber orientation analysis, the Poisson’s ratio (v12) result is recorded for each tetrahedral element in the model at the end of the analysis.
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. In models analysed using Midplane or Dual Domain analysis technologies, because of the plain stress assumption in the shell structure analysis in Warp, only 4 mechanical constants (tensile modulus in first/second principal directions, Poisson ratio v12, shear modulus G12) are necessary.