Effect of Ply Thickness on the Damage Development in Composite Laminates (preprint)

This paper describes the experimental investigation on the effect of ply thickness on the first ply failure, delamination, and the subsequent final failure of graphite/epoxy composite laminates. The laminates considered in this paper are a cross-ply and two quasi-isotropic laminates containing thin plies in the desired interface. The onset of the first ply failure and delamination, and the stress-free temperature are experimentally determined. The experimental results for ply crack and delamination development were compared with an analytical model. The results indicated that ply thickness played a significant role on delaying damage onset. The experimental results were compared with the Weibull statistical theory in conjunction with the weakest link theory and discussed on the effect of size (ply thickness) on damage initiation.