Designing for damage tolerance in aerospace: A hybrid material technology

•The state-of-art knowledge base on the FML technology is provided.•First principle theories for FMLs allow multi-disciplinary design approaches.•FML are considered a structure rather than material.•Knowledge-based design methodologies for FMLs are discussed.

This paper provides an overview of damage phenomena and mechanisms in hybrid aerospace structural materials subject to damage tolerance certification requirements. Because the hybrid technology originates from the objective to design for damage tolerance, the paper starts with illustrating recent developments in this material technology. Subsequently, the damage mechanisms that occur under quasi-static, fatigue and impact loading are discussed. Explanations of these phenomena are given with theories following fracture mechanics and energy balance approaches. To illustrate the top-down design approach these fundamental theories enable, potential future solutions are presented to design against these damages in order to improve damage tolerance.