Review of z-pinned laminates and sandwich composites

Z-pinned laminates and sandwich materials are an important class of composites with current applications in aircraft and emerging uses in other light-weight engineered products. This paper reviews research advances in the manufacture, microstructural chacterisation, mechanical properties, environmental durability and other functional properties (e.g. electrical, thermal, damage sensing) of z-pinned composite materials and structures. The review reveals that z-pins can be used in create novel multifunctional laminates that uniquely combine a multitude of important properties including high interlaminar fracture and fatigue resistance, superior impact damage tolerance, increased thermal and electrical conductivities, damage sensing, and high-performance joining. Similarly, z-pins can impart sandwich composites with a novel combination of multifunctional properties that include high structural, damage tolerance, electrical and damage sensing properties. Research gaps in our understanding of z-pinned laminates and sandwich composites are identified. Future research opportunities to create next-generation z-pinned materials with even more versatile multifunctional properties are described.