A thermodynamically consistent continuum damage model for time-dependent failure of thermoplastic polymers

In this study, a thermodynamically consistent damage model is presented to predict failure in glassy polymers. This model is based on the Eindhoven Glassy Polymer (EGP) multimode model, and it considers the effects of plastic deformation and hydrostatic stress on damage evolution. The model is implemented as an ABAQUS user material (UMAT) subroutine. Three experiments are simulated to show the model's abilities. First, the model is used to predict failure in a T-fitting burst pressure test to investigate the model's capabilities in predicting damage evolution and failure. This test shows two failure locations one dominated by the plastic deformation and the other by the hydrostatic stress and provides the possibility to investigate the model capabilities in capturing these contributions to the failure. Through comparison with experimental results, it is demonstrated that the model can effectively take into account the influence of hydrostatic stress and plastic deformation on failure. Second, the D-split test of notched pipe rings is simulated to show the time-dependent behavior of the model. Third, the cyclic behavior of a polycarbonate specimen under compression is investigated.