Modelling of the mechanical behaviour of amorphous glassy polymer based on the Quasi Point Defect theory—Part I: Uniaxial validation on polycarbonate

This paper is devoted to the modelling of the viscoelasto-viscoplastic behaviour of amorphous polymers based on the Quasi Point Defects (QPD) theory. A summarized and unified description of the main assumptions is presented in its scalar formulation to compute the complex viscoelasto-viscoplastic behaviour of an amorphous medium in the glassy state from linear to non-linear ranges. Based on an original scenario for the microstructural reorganization caused by an external thermomechanical stimulus and related to the two main relaxation processes, this theory allows a coherent description of the material response under large conditions of temperature and strain rate by using a single set of material parameters. A convincing validation is performed on a ductile bisphenol-A polycarbonate (PC-BPA) by comparison between computed results and experimental measurements.