Tensile and Shear Experiments using Polypropylene/Polyethylene Foils at different Temperatures

Abstract

An experimental campaign on a thermo-plastic copolymer of polypropylene/polyethylene (PP/PE) serves to investigate the rate- and temperature-dependence of the material. Isothermal tensile and shear experiments for four different constant displacement-rates and temperatures (−10 ◦C - 120 ◦C) are conducted, monitored by means of a Digital Image Correlation (DIC) system. The tensile experiments are carried out within the large deformation range, where localization phenomena are observed. This requires the application of a full-field deformation analysis system to develop stress-stretch (strain) diagrams, which are necessary with regard to aspects of constitutive modeling. In addition to these experiments, a modified three-rail shear tool was designed in order to investigate the shear behavior of PP/PE. Apart from the rate-dependence, the relaxation behavior is investigated for both tensile and shear load conditions by means of multi-step relaxation tests at different temperatures in order to obtain indications about the equilibrium stress state of the material.