Comparative study of the simulation effectiveness of the polymer’s viscoplastic response between a viscoplastic and a fractional viscoelastic model

The scope of the present work is to study, experimentally and theoretically, the temperature and strain rate effect on the yielding and postyielding tensile behavior of an epoxy resin. Regarding the theoretical study, a three-dimensional viscoplastic model, namely a Zener B model, associated with the decomposition of the total strain into elastic and viscoplastic part was employed. To have an integrated aspect regarding the various models potentiality, a fractional Zener B viscoelastic model was comparatively utilized. Due to the limited capability of the two well-known models to describe the strain softening, exhibited by the polymeric material, apart from a stress-dependent viscosity related to a nonlinear Eyring-type dashpot, a strain-dependent activation volume was considered to be developed by a distribution function. The strain hardening hereafter was simulated by a back stress, associated with a hyperelastic spring. The strain rate effect could be successfully predicted by the scaling rule valid in viscoelasticity. No essential superior capability simulation was deduced from the comparative study between the two models.