Design and Validation of Fully-Uncoupled Multi-Directional lay-ups to evaluate interlaminar fracture toughness

Fibre reinforced composites are widely used in structural applications, thanks to their excellent specific properties, which allow important weight saving. Nonetheless, to design safe structures, the damage mechanisms typical of composite laminates must be deeply understood. Among these mechanisms, interlaminar failure, or delamination, is one of the most dangerous. It can propagate within a structure without being noticeable from the outside. Due to thermoelastic coupling problems, the scope of delamination resistance testing techniques is limited to specimens with unidirectional layups, while real structures are built using multidirectional layups and hence have many different types of interfaces. In this thesis, new layups that solve this problem and allow to evaluate delamination resistance of all interface types are developed and validated.