Characterization of mixed-mode II and III interlaminar fracture of CFRP laminates

摘要

Because of their inherent weakness in the thickness direction of laminated composites, characterization of interlaminar fracture is crucial to realize the failure tolerance of the laminates. Considering that delamination propagation is caused by not only interlaminar normal stress field but also in-plane and out-of-plane shear stress field, fracture behavior of all three individual modes and/or that of mixed-modes should be characterized. Although understanding of fracture of three individual modes and mixed mode I and II have been promoted by dissemination of test methods such as DCB, ENF, ECT and MMB, fracture behavior of mixed-mode including mode III has not been described yet in detail due to the lack of appropriate test method. Accordingly, the behavior of CFRP laminates under mixed-mode II and III failure condition was studied with DNSCB test method proposed recently.