Characterisation of the mode I interlaminar fracture toughness in multidirectional interfaces in a 3D-printed composite

Debonding between plies, or delamination, is a critical failure mechanism for laminated composite materials and has been analysed in several scientific investigation. Usually in real applications delamination initiates and propagates between interface layers with different reinforcement orientation. However, most of the experimental works are carried out using unidirectional specimens for determining the interlaminar fracture toughness because in laboratory conditions it is difficult to propagate the crack between multidirectional interface layers without other failure mechanisms that invalidate the test. Among these failure mechanisms, crack plane migration and crack branching at several planes are the most common. In this communication it will be detailed and analyzed the experimental characterization of the interlaminar fracture toughness in multidirectional interfaces of 3D-printed composite materials is detailed, including the manufacturing process of the Double Cantilever Beam (DCB) specimens that warranty crack propagation under pure mode I loading and without plane migration. Finally, a quantitative comparison is carried out between multidirectional interlaminar fracture toughness and the unidirectional one and a fractography analysis is reported. © 2024, Scipedia S.L.. All rights reserved.