ABSTRACT
The mixed-mode fracture of matrix-dominated composite laminates containing central holes or cracks was studied using some graphite/epoxy off-axis AS4/3502 balanced symmetric laminates. This chapter distinguishes the terms notch sensitivity and notched shape sensitivity with examples. Anisotropic finite width correction factors were applied to interpolate the experimental data. In general, the predicted notched strength and the failure initiation locations correlate reasonably well with the experimental results. An experimental program using the graphite/epoxy AS4/3502 off-axis symmetric laminates, containing either a circular hole or a central crack, was designed to study the mixed-mode failure mechanism and fracture strength of matrix-dominated composite laminates under tensile loading. The stress distribution of infinite anisotropic plates containing an elliptical opening has been derived earlier under in-plane combined loading condition. The ultimate strength ratio of a notched composite laminate versus unnotched laminate is predicted using the first-ply failure (FPF) strength of the notched laminate divided by the FPF strength of the corresponding unnotched laminate.
