Determination of the flexural behavior of UHMWPE under different deformation velocities: Experimental and nümerical study

Ultra high molecular weight polyethylene (UHMWPE) considered as a semi-crystalline polymer has been widely used in a broad range of engineering applications, such as biomedical, defense, automotive and aviation due to its superior physical and mechanical properties, including lightweight, very low coefficient of friction, high wear resistance, high impact resistance, high chemical and corrosion resistance and high noise absorption. In these application fields, UHMPWE are generally subjected to multiaxial loads, like bending at different deformation velocities. First, determining the mechanical response of this material to bending loads experimentally, and then predicting its material behavior under bending loads in the context of finite element analysis accurately is of industrial need. On account of this, the primary aim of this study is to first determine the material behavior of UHMWPE under three-point bending at different deformation rates through mechanical tests, and then to reproduce the 3-point bending test data satisfactorily by means of numeric analysis. In this framework, the 3-point bending tests have been carried out on UHMWPE at three various deformation rates such as 0.1 mm/s, 1 mm/s and 12 mm/s. The numerical implementation of the 3-point point bending tests has been performed using SAMP- 1 material model (semi-analytical material model for polymers) in LS-DYNA engineering software. The required input material parameters to SAMP-1, including multiple tensile plastic stress-strain and compressive plastic stress-strain curves have been obtained by conducting associated mechanical tests at the identical deformation rates attained in the actual 3-point bending experiments. Such characteristic material behavior of UHMWPE under tension and compression, including strain softening followed by strain hardening, has been successfully captured by SAMP-1. It has been observed that the UHWMPE acts stiffer with an increased deformation rate, and a very good correlation has been achieved between 3-point bending outcomes and numerical predictions.