Mixed mode I + II interlaminar fracture of glass/epoxy multidirectional laminates – Part 2: Experiments

Mixed-mode bending (MMB) tests were performed on glass/epoxy multidirectional specimens with delaminations in 0/θ and θ/−θ type interfaces. The initiation mode I and mode II strain energy release rates (GI and GII) were obtained from the modified beam theory (MBT) data reduction scheme presented in part 1. Measured compliances agreed well with MBT predictions. Critical energy release rate Gc versus GII/G fracture loci were built with results of MMB, double cantilever beam (DCB) and end notched flexure (ENF) tests. In spite of some discrepancies, fracture loci appeared to be linear. Gc values increased moderately with θ for both 0/θ and θ/−θ interfaces.