Size Effects in Tensile, Compressive and Interlaminar Failure of Unidirectional Composites

Abstract

A summary is given of experimental results on size effects for different failure mechanisms from geometrically scaled tests on unidirectional composites. Size effects for tensile failure were observed from three sets of scaled flexural tests in a four point bending rig for both glass and high strength carbon fibre/epoxy. Tests on intermediate modulus carbon fibre/epoxy in a pin-ended buckling rig produced compressive failures, and showed a larger size effect than for tensile failure. Scaled curved beam bending tests were used to investigate size effects in interlaminar tensile strength, and short beam shear tests for interlaminar shear strength. Significant size effects on interlaminar strength were found for both glass and carbon fibre/epoxy.