Effect of stacking configuration on dynamic tensile properties of braided carbon fibre composites under medium-low strain rates

Abstract

The dynamic tensile properties and failure modes of moulded 2 × 2 braided CFRP were investigated by using a high-speed hydraulic tester, combined with a high-speed camera and digital image correlation technology. The test is under six strain rates (1 s−1, 10 s−1, 100 s−1, 250 s−1, 500 s−1, and 800 s−1) and three stacking sequences ([0/90]12, [0/90/±45]3s, and [±45]12). Failure of the fibre and matrix at fracture was observed via SEM. The stress-strain responses under different strain rates were discussed, as well as the variation laws governing the elastic modulus, tensile strength, and fracture strain with respect to strain rate. The results show that the elastic modulus increased by 10%–30% with an increase in strain rate and the ±45° direction had a higher strain rate sensitivity. The tensile strength increased by 30%–40%; however, the change in fracture strain varied with different stacking sequences.