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A numerical method is developed for 3D delamination modeling in composites based on fundamentals of computational plasticity, computational contact mechanics and fracture mechanics. Composite plies are modeled with 3D solid and pentahedral discrete/finite elements and the interlaminar behavior of plies is considered using combination of an anisotropic bilinear strain- softening plasticity model and the Penalty method. Numerical examples are investigated to assess the ability and performance of the method. .