INTRA-LAMINAR FRACTURE IN ANGLE-PLY LAMINATES

The development of matrix cracking in (0/theta/0) GFRP laminates, wher e theta = 45 degrees, 54 degrees, 75 degrees and 90 degrees, has been investigated. Crack initiation and propagation in the theta degrees pl y were studied separately by using unnotched and notched samples. Deta ils of average crack initiation/propagation strains and associated ply stresses, calculated from laminate theory, as functions of off-axis p ly angle are presented and discussed for all laminates along with inve stigations of notch depth effects and crack growth patterns. It is sug gested that to a first approximation crack propagation is governed by the transverse stress while crack initiation has a more complex and as yet unknown dependence on stress state. (C) 1997 Elsevier Science Lim ited.