Micromechanical modelling of interlaminar damage propagation and migration

Interlaminar crack onset and propagation in fibre-reinforced composites is here investigated in detail through the development of a micromechanics framework. The different dissipative effects that characterize crack propagation are assessed by using the appropriate constitutive material models. The phenomenon of delamination migration between angled plies is studied by embedding unit cells in-between homogenized plies. Different features associated with delamination migration are analyzed, such as the distribution of interlaminar shear stresses at the crack tip and the kink angles, aiding in the understanding of the complex phenomena linked to interlaminar crack migration. In addition, the influence of through-thickness compressive stress on the mode II interlaminar fracture toughness is studied and verified by comparing numerical predictions with experimental results, showing that the proposed computational framework represents a sound tool that can be used to better understand the micromechanics of interlaminar failure in advanced composite materials.