Fatigue Behaviour of Surface-Cracked Glass/Polyester Composite Plates

This paper reports on the fatigue behaviour of surface–cracked glass/polyester composite plates. The machined cracks have various aspect ratios (a/c) and depth ratios (a/t). The propagation behaviour of surface cracks and delamination are investigated under constant-amplitude (R ¼ 0) loading. The stress intensity factor, KI , is obtained using Newman–Raju and Paris and Sih equations, while Kdel is determined using equations given by Suo and Hutchinson and Bao et al. The results were plotted as curves of the typical relationship between the crack growth rate (dc/dN) and the stress intensity factor range (KI) and the delamination propagation rate (db/dN) and the delamination stress intensity factor range (Kdel). Material constants A and n were obtained according to the Paris–Erdoğan equation.