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

摘要

Tensile behavior of extruded short E-glass fiber reinforced polyamide-6 composite sheet has been determined at different temperatures (21.5deg C, 50 deg C, 75 deg C, 100 deg C) and different strain rates (0.05/min, 0.5/min, 5/min). Experimental results show that this composites 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 deg C and 50 deg 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 modela re a stress exponent n and a stress coefficient sigma.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 sigma, on the other hand, varies with both strain rate and temperature.