Study on strain-rate-dependent behaviour and constitutive model of long glass fibre reinforced polypropylene composite

Abstract

Accurate material model under different strain rates (˙ε) is important for numerical simulations in vehicle design and crashworthiness assessment. Therefore, the objectives of this study are to develop the constitutive model of long glass fibre reinforced polypropylene composite (hereinafter referred to as 'LGFRP') which related to strain rate range of 10-3/s-50/s. Tensile and compression tests are conducted at different strain rates. The experimental results show that the failure strain and ultimate strength increase as increasing strain rate. The elastic modulus is sensitive to strain rate in tensile tests, but less sensitive to strain rate in compression tests. According to the experimental results, a novel constitutive model proposed by the authors is used to represent stress-strain relationship related to strain rate of the LGFRP. The analysis results show that the novel constitutive model agrees well with the experimental results.