Analysis of the strength and fracture behaviour of unidirectional and angle-ply graphite-aluminium composites

Abstract

The tensile behaviour of unidirectional and [±θ]s angle-ply P100 graphite-reinforced 6061-Al composites was determined as a function of the angle (θ) between the fibre and the applied load. The experimentally determined values of the elastic modulus and tensile strength of the composites are compared with those predicted from classical laminate theory. The measured elastic modulus values agreed with theoretical values, but the strength of the [\+-\gq]s angle-ply composites was substantially greater than predicted. The discrepancy between experiment and theory is attributed to the stress required to fail the fibre ply/separator foil interface present in the angle-ply composites. The composite failure modes are also documented, and it is shown that the separator foils of the angle-ply composites shift the transition from tensile to shear failure to greater values of\gq relative to the off-axis unidirectional composites.