3 - Fibre-dominated failures of polymer composites

Abstract

The fracture morphologies associated with fibre-dominated or translaminar fracture are described. The approach is to present the morphologies associated with unidirectional laminates first, starting with single-mode failures under tension and compression stress. Flexural failure in unidirectional laminates, which involves a combination of tension and compression failure modes, is presented. The important mode of intralaminar fracture (fracture along the interface between the fibres and matrix) is described. In-plane (translaminar) shear failure of simple unidirectional layers is considered, although this failure mode can only develop within multidirectional laminates since the constraint of the supporting plies is required. After considering unidirectional laminates, the fracture morphologies of more complicated non- unidirectional laminates are described, starting with the simplest of these; cross ply (0 °/90 °) laminates. Tension, compression and flexure in cross-ply laminates are presented. Failure of these laminates is more complex than unidirectional failures, but is generally a combination of these basic failure mechanisms. Finally, the failure morphologies in tension, compression and flexure in multidirectional laminates are presented.