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.