Effect of core design on energy absorption and structural integrity of sandwich composites - A comprehensive review

Sandwich composite structures (SWCs) are extensively used in structural, aerospace, marine, and automotive applications due to their high specific stiffness and specific strength, along with superior energy absorption capabilities. The ability to integrate diverse materials and geometric configurations enables the development of tailored, multifunctional engineering systems. This review examines the influence of geometric design parameters on the energy absorption (EA) response and overall mechanical performance of SWCs. Key parameters identified from the literature include core density, core thickness, number of core layers, foam-filled versus unfilled cores, cell size, and inter-core spacing. The selection of suitable core materials, combined with optimal core topology, is shown to significantly govern the synergistic structural behavior of SWCs. A comprehensive comparison of various core architectures—such as honeycomb (HC), modified honeycomb, resin-impregnated honeycomb, foam, corrugated, lattice, auxetic, and bio-inspired configurations—is presented, emphasizing the relative advantages and challenges. Furthermore, the effects of geometric variations, loading conditions, and material density on impact performance are systematically discussed. The findings provide consolidated insights and design guidelines for the development of high-performance SWCs in advanced engineering applications.