A modified constitutive equation for unidirectional composites under tensile impact and the dynamic tensile properties of KFRP

On the basis of the integral stress/strain curves of unidirectional GRP at a strain rate 300/s and the coated-fibre-bundle model, a modified one-dimensional elastic brittle damage constitutive equation for GRP is proposed by adopting the double Weibull distribution function to describe the strength distribution of the coated glass fibre instead of a single Weibull function. The modified constitutive equation can characterize integrally the macroscopic tensile mechanical behaviour of GRP under tensile impact. Furthermore, The tensile impact experiments on unidirectional KFRP are performed at strain rates 150/s, 400/s and 1500/s. Experimental results show that the mechanical properties of KFRP are rate dependent. The coated-fibre-bundle model and the modified constitutive equation are extended to KFRP. Consistency between the simulated results and the experimental data confirms that the coated fibre bundle model and the modified constitutive equation are valid.