Delamination Growth In Unidirectional Glass/Epoxy Composite Under Static And Fatigue Loads

Both static growth of cracking and delamination fatigue-crack growth experiments have been carried out on unidirectional glass/epoxy laminates. Three specimen types were tested: double cantilever beam (DCB), mixed-mode bending (MMB) and endloaded split (ELS), for mode I, mixed-mode (I+II), and mode II loading, respectively. They have been expressed in terms of the total fracture resistance, GTR, in static loading, and the measured delamination growth rates, da/dN, versus the total strain energy release rate , in fatigue loading. A large number of GH/GI mode ratios have been studied. For each modal ratio, several specimens were tested. Experimental results were correlated through the plotting of the total fracture resistance, GTR, versus the GH/GI modal ratio, and of the parameters d and B versus the GH/GI modal ratio. Good agreement was obtained between theses experimental results and calculations from a semi-empirical relationship.