High-speed tensile tests on a polypropylene material

International audienceThe mechanical behaviour of a copolymer polypropylene material (PPC7712) was studied under high strain rate tension loading conditions. For this purpose, a servo-hydraulic machine was equipped with a novel experimental device involving an original grip system. Stress-strain measurements were performed with strain gauges. The aim of the study was to determine the effects of the strain rate on the stress-strain behaviour, the tensile strength and the onset of the fracture process. Various strain rates ranging from 0.8 to 200 s!1 were tested. The tensile strength was found to increase with the strain rate. The strain rate dependent behaviour of the material was described using the phenomeno- logical Hyperelasto-Visco-Hysteresis model (HVH model) previously used with the results of quasi-static tensile tests on this material. The effects of the strain rate were given in this model by the changes in the viscous parameters