Competing failure mechanisms in mixed-mode fracture of an adhesively bonded polymer-matrix composite

In this paper, the use of cohesive-zone models to analyze crack-path selection in adhesive joints made from a polymer-matrix composite is demonstrated. Cohesive-zone parameters for the adhesive and composite obtained in a previous work were used without any modifications to make the predictions presented in this study. The results of numerical simulations of two mixed-mode geometries, single-lap shear and asymmetrical double-cantilever beam specimens, are compared to experimental observations. It is shown that the numerical simulations provided reasonably good predictions for the strength and failure mechanisms of the joints, allowing the nature of the competition between failure of the composite and failure of the interface to be determined.