Micromechanical analysis of interlaminar crack propagation between angled plies in mode I tests

This paper presents a micromechanical finite element model to study interlaminar damage propagation and relocation, known as delamination migration, between angled plies, consisting of a double-ply θ/0° Unit Cell (UC) in-between homogenised unidirectional 0° plies. Random fibre distributions and appropriate constitutive models are used to model the different dissipative phenomena that occur at crack onset and propagation. Varying the upper ply fibres orientation, θ, and ply thickness, it is possible to assess their influence on the damage migration mechanism. Different features associated with delamination migration are analysed, such as the distribution of interlaminar shear stresses at the crack tip and the kink angles. When comparing the results of the micromechanical model with previously conducted experimental observations, similar trends are obtained. It is concluded that the computational framework is able to simulate mode I interlaminar damage propagation and delamination migration in multidirectional laminates, providing a sound tool to better understand the conditions behind interlaminar crack migration.