Mode II interlaminar fracture of glass/epoxy multidirectional laminates

Abstract

An experimental study was conducted on the mode II interlaminar fracture of woven fabric glass/epoxy multidirectional laminates. A preliminary Finite Element analysis was used to choose stacking sequences for End-Notched Flexure specimens with starter delaminations on theta/-theta and 0degrees/theta interfaces. The experimental G(IIc) values generally increased with the ply angle theta for both theta/-theta and 0degrees/theta specimens. These results were in agreement with the predictions of an average interlaminar stress fracture criterion. In contrast with previous studies on unidirectional laminates, G(IIc) values from a mode II precrack were significantly higher than those from the film, thus revealing a pronounced R-curve effect.