Stress Corrosion Cracking of Notched GFRP Laminates (Microscopic Fracture Model and Crack Propagation Rate)

This paper presents stress corrosion cracking (SCO of notched GFRP laminates under an acid environment. Based on a fractographic analysis, it is found that the stress-corrosion cracking a is governed by a breakage of the warp fiber strand. The crack propagation rate is possible to estimate from a microscopic fracture model of the warp fiber strand. To obtain the crack propagation rate, a fracture model is proposed on the basis of some assumptions as follows: (1) A relation between an applied stress and a mirror zone radius (in the fracture surface of the warp fiber) obeys the Jaras's equation, (2) Shape of the warp strand's shape is almost an ellipse, (3) The crack is a self-similar one during the propagation. The crack propagation rate is obtained as a function of the stress intensity factor. It is found that its value agrees the experimental value, and confirmed that the proposed microscopic fracture model is appropriate for evaluating the crack propagation rate in an acid environment.