Modelling the effect of temperature on the plastic deformation of high-density polyethylene (HDPE) : a semi-empirical approach

Abstract

External factors, including strain rate and temperature, influence the plastic deformation of the high-density polyethylene (HDPE) polymer. In this paper, we present the results of uniaxial tensile experiments at different temperatures (20°C, 30°C, 40°C, 50°C, 60°C, 70°C) and strain rate (0.00196/s; 0.0049/s; 0.009/s; 0.0294/s) conditions, and propose a new semi-empirical approach to model the temperature-dependent flow stress of the material. The proposed model identifies strain hardening as a transient and softening (strain or thermal) as a steady state phenomenon and superimposes their contribution. The material parameters are determined via regression analyses of the experimental data. Furthermore, we used a finite element (FE) analysis to model the plasticity using an analytical hardening function on COMSOL Multiphysics. The proposed theoretical and FE models are interrelated and are compared with the experimental and the well-known Johnson-Cook plasticity model at a reference strain rate. Our findings show that the flow stress modelling by the proposed and FE approaches are similar and agree with the experimental results. With a maximum of 5.28 % calculated error, both methods were better than the Johnson-Cook model in most cases.