A mixed mode cohesive law for Z-pinned composite delamination

A new methodology for modeling Z-pin reinforcement in composite laminates is presented, in which continuum cohesive elements are used to represent the Z-pins. A coupled cohesive zone model is developed to incorporate both the interlaminar failure and the failure of Z-pins. The standard mode I/II delamination toughness tests of Z-pinned composite laminates and the Z-pinned composite T-joints subject to bending load were analysed. Comparison between the numerical simulation and the experimental results approved the applicability and validity of the present model. The modeling methodology allows for convenient implementation and is flexible enough to account for different Z-pin densities and distributions. The successful application of the methodology to other reinforcements has also been demonstrated.