Modeling the inelastic deformation and fracture of polymer composites – Part I: Plasticity model

A new transversely-isotropic elastic–plastic constitutive model for unidirectional fiber reinforced polymers (FRP) is presented. The model is able to represent the fully nonlinear mechanical behavior under multi-axial loading conditions and under triaxial stress states prior to the onset of cracking. Since associated flow rules often give a wrong prediction of plastic Poisson coefficients, a non-associated flow rule is introduced to provide...