Effects of temperature and strain rate on the tensile behavior of short fiber reinforced polyamide‐6

Abstract

Abstract Tensile behavior of extruded short E‐glass fiber reinforced polyamide‐6 composite sheet has been determined at different temperatures (21.5°C, 50°C, 75°C, 100°C) and different strain rates (0.05/min, 0.5/min, 5/min). Experimental results show that this composite is a strain rate and temperature dependent material. Both elastic modulus and tensile strength of the composite increased with strain rate and decreased with temperature. Experimental results also show that strain rate sensitivity and temperature sensitivity of this composite change at a temperature between 25°C and 50°C as a result of the glass transition of the polyamide‐6 matrix. Based on the experimental stress‐strain curves, a two‐parameter strain rate and temperature dependent constitutive model has been established to describe the tensile behavior of short fiber reinforced polyamide‐6 composite. The parameters in this model are a stress exponent n and a stress coefficient σ*. It is shown that the stress exponent n , which controls the strain rate strengthening effect and the strain hardening effect of the composite, is not only strain rate independent but also temperature independent. The stress exponent σ*, on the other hand, varies with both strain rate and temperature.