Fracture and Failure Mechanisms for Different Loading Modes in Unidirectional Carbon Fibre/Epoxy Composites

This chapter provides an overview of fracture behaviour under interlaminar delamination failure mode in unidirectional carbon fibre reinforced epoxy composite (CFRP) laminates. It explains delamination toughness and the failure mechanisms operating in different loading modes (pure modes I and II and mixed mode I/II) in two different materials: AS4/8552 and AS4/3501-6 unidirectional long carbon fibre/epoxy composite laminates. These are the most widely loading modes used and well established in the scientific literature. The onset and growth of delamination in unidirectional composite materials is studied from different points of view, employing experimental and numerical procedures and fractographic observation of the delaminated surfaces. A good agreement is found between experimental and numerical results, since the results obtained in both procedures show errors below 10%.