Interlaminar fracture under mixed-mode II + III and I + III

Abstract

This paper presents two new interlaminar fracture test methods for mixed-mode II + III and I + III loadings. Both tests involve biaxial bending of edge pre-delaminated plate specimens with a cross-ply lay-up. The tests allow the coverage of a wide range of mode mix ratios. However, they require finite element analyses for selecting specimen configurations and experimental data reduction. Moreover, a relatively complicated fixture is needed for the mixed-mode I + III test, while geometric non-linearity is significant in the mixed-mode II + III one. Nevertheless, realistic fracture envelopes were obtained for carbon/epoxy laminates.