Research progress on core reinforcement technology for foam sandwich composites

Foam core sandwich structures are widely used in lightweight engineering applications due to their high specific stiffness and energy absorption capability. However, under critical loading conditions such as compression, bending, and impact, their performance is often constrained by limited core strength, weak face-core interfacial bonding, and poor damage tolerance. These structural and performance limitations significantly restrict their application in demanding service environments. To address these challenges, various foam-core reinforcement strategies have been developed to enhance the mechanical performance and failure resistance of sandwich panels. This review systematically summarizes recent advances in particle-reinforced, fiber-reinforced, and composite or structural foam core sandwich structures. Particular emphasis is placed on how different reinforcement concepts improve compressive strength, shear and flexural performance, resistance to delamination, and impact energy absorption. By comparatively analyzing the reinforcement mechanisms, mechanical property enhancements, and inherent limitations of each strategy, this review provides a comprehensive overview of current research progress and identifies key directions for the design of high-performance foam-based sandwich structures.