Failure and complex crack patterns in hybrid laminates: A phase-field approach

A powerful numerical instrument, which reproduces the complex failure mechanisms of hybrid laminates under in-plane loading conditions, is developed within the framework of phase-field modelling. The ruptures, strongly influenced by geometrical and mechanical properties of the plies and affected by the state of stress, are arranged as delamination of the adhesive interface and intricate crack patterns within the layers. Therefore, the mechanical response of a hybrid laminate is obtained by studying the simplified layup of two elastic-brittle solids connected by a cohesive interface. Explicit and well detailed simulations illustrate peculiar failure mechanisms, validated, when possible, against experimental results taken from the literature and compared to simplified analytical models. Different in-plane loading conditions are explored together with the possibility to include material anisotropy. The proposed model is a first attempt to provide an effective design tool for the understanding of the intriguing failure of hybrid laminates and the enhancement of their mechanical properties like ductility.