Fracture and tensile fatigue properties of stitched fibreglass composites

摘要

The effect of through-thickness stitching on the in-plane fracture toughness and tensile fatigue properties of a glass reinforced polymer composite is investigated. A large improvement in the fracture toughness of fibreglass composites can be achieved by stitching. It is discovered that stitching can force the crack to follow a tortuous path from stitch to stitch, and this improves the fracture resistance. However, the ability of stitching to increase the fracture toughness is critically dependent on the stitch pattern. Stitching is found to shorten the tensile fatigue life of the fibreglass composite. The fatigue damage mechanisms are investigated, and it is shown that crimping and distortion of load-bearing fibres by the stitches results in the early formation of cracks which is the cause of the reduced fatigue life. As with the in-plane fracture toughness, the fatigue performance is affected by the stitch pattern.