Research Progress on Impact Mechanical Properties of Closed-Cell Foam Sandwich Composite Structures

Closed-cell foam sandwich composite structures are widely used in aerospace impact-resistant protective structures. However, such materials are subjected to various forms of impact loads during service, and the resulting damage poses significant threats to structural integrity. This paper systematically reviews the mechanical behavior of core and composite face-sheet components, their dynamic structural responses, and their effects on sandwich structures. The responses and analytical methods for closed-cell foam sandwich composite structures under different impact velocities are categorized. Under high-velocity impacts, structural failure modes such as delamination and penetration dominate, while low-velocity impacts tend to induce hidden damage like face-sheet-core debonding, with energy absorption mechanisms governed by core parameters and layup configurations. Additionally, future directions for enhancing the impact mechanical performance of sandwich composite structures are discussed.