Comparison between the inter- and intra-laminar fatigue crack propagation as obtained from DCB and cross-ply specimens

Abstract

The fatigue life of multi-directional composite laminates is characterised, in the earlier stages, by the initiation and propagation of multiple off-axis cracks. These cracks involve the entire ply thickness and propagate along the fibre direction. In a schematic geometrical representation, thus, the crack faces belong to the 1-3 plane, where 1 is the fibre direction and 3 is the through-the-thickness direction.