Static and dynamic tensile behaviour of polycarbonate connected to the deforming specimen shape

Abstract

Like other structural thermoplastic polymers, polycarbonate (PC) exhibits a typical two-stage plastic deformation mode, including a first phase of strain localization and a second phase of strain propagation. At the same time, the stress-strain curves at the local scale undergo two distinct loading phases connected by a softening-instability decreasing phase. This mechanical response is not yet fully recognized and the reproduction of the peculiar phenomena in numerical simulations is not yet commonly standardized. In this work, the relationship between the straining/loading macroscopic response and the material flow curve at the local scale is investigated in detail, aiming at the two-way relationships enabling to infer the latter curve from the former data. Experimental tests at static and dynamic rates are carried out to verify how the special features of the PC are affected by the strain rate and to estimate its rate sensitivity.