Modelling the cyclic elasto-viscoplastic behaviour of polymers

The mechanical behaviour of polymeric materials presents some peculiarities, especially regarding the evolution of their hardening under stresses above the proportional limit. For many types of polymers (Epoxy, Polyamides, Polyvinylidene, etc.) the elastic properties are not rate-dependent, and the behaviour is elasto-viscoplastic. Also, in the case of load-unload tensile tests, preliminary studies show that the kinematic hardening of this kind...