Property modeling across transition temperatures in PMC's: Part II. Stress rupture in end-loaded bending

The quasi-static properties (strength and stiffness) of polymer matrix composites (PMC's) exhibit significant temperature dependence in tension. Part I of the present paper introduced a new model enabling the computations of the strength and stiffness of PMC's in tension as an explicit function of temperature. In the second part, this model was used to model the behavior of unidirectional PMC's (AS4/PPS) in end-loaded bending. A new set of stress-rupture experiments was performed on the amorphous composite in bending in order to complete the data available in the literature (based on semi-crystalline composite). A model enabling the computation of the rupture life of the bent specimen as a function of temperature and applied load was established. The theoretical simulations were successfully compared to a set of 7 independent end-loaded bending experiments. This paper demonstrates the validity and the ease of integrating the polymer stiffness-temperature model in mechanics of composite materials, and completes the theoretical and experimental basis for the modeling of the end-loaded behavior of PMC's.