Micromechanical modelling of short-term and long-term large-strain behaviour of polyethylene terephthalate

摘要

A micromechanically based model is used to describe the mechanical behaviour of polyethylene terephthalate (PET) under uniaxial compression up to large strains and at different temperatures. The creep behaviour of isotropic PET is simulated and compared to experimental data to demonstrate the applicability of the model to describe the long-term response. The material is modelled as an aggregate of two-phase layered domains, where different constitutive laws are used for the phases. A hybrid interaction law between the domains is adopted. The crystalline phase is modelled with crystal plasticity and the amorphous phase with the Eindhoven Glassy Polymer model, taking into account material ageing effects. Model parameters for the selected constitutive laws of the phases are identified from uniaxial compression tests for fully amorphous material and semicrystalline material. Texture evolution during the deformation predicted by the model adequately matches previously observed texture evolution.