A constitutive model of the compressive mechanical properties of ultra high molecular weight polyethylene (UHMWPE) at different temperatures and different strain rates

Abstract

The impact resistance of UHMWPE is related to temperature and strain rate. In order to determine the compressive mechanical properties of UHMWPE, quasi-static and dynamic compression tests were conducted on UHMWPE using an MTS universal testing machine and split Hopkinson pressure bar equipment, respectively. Stress-strain curves for UHMWPE over the temperature range of -40 °C∼100 °C and strain rate range of 0.001∼3300 s-1 was generated. By comparing the stress-strain curves of UHMWPE with molecular weights (MWs) of 3, 6 and 9 million in a quasi-static state, it was found that UHMWPE with a MW of 6 million had better compressive mechanical properties than other UHMWPE samples. Using the stress-strain curves for UHMWPE with a MW of 6 million at different strain rates and temperatures, the yield strength of UHMWPE increased with an increasing strain rate and decreased with increasing temperature were obtained. Based on the quasi-static and dynamic experimental results for UHMWPE with a MW of 6 million, a constitutive model of plasticity at different temperatures and strain rates was established. This model agreed well with the experimental results. This study provides both theoretical and empirical reference for the study of the mechanical properties of UHMWPE materials.