Multiscale modeling for large deformation of glassy polymer based on molecular chain slip model and probabilistic response law of inelasticity

A new concept of "molecular chain slip system" for polymers is analogically proposed on the basis of crystal plasticity theory for metals. A multiscale model that can reproduce the large deformation behaviors of glassy polymer is developed allowing an independent rotation of a slip system differently than the usual crystal plasticity framework. The inelastic response law based on a probabilistic theory considering change of local free volume is adopted as a hardening law. An FE simulation on tensile test of a glassy polymer plate is carried out using the present model. The macroscopic propagation of neck with high strain rate shear band, the directions of molecular chains in the oriented region and the change of distribution of local free volume are computationally visualized. Furthermore, the nonlinear viscoelastic behavior before the initial yielding, which cannot be expressed by the conventional hardening law, is predicted.