Failure Mechanism and Energy Absorption of Multilayer Honeycomb Sandwich Structures Under Low‐Velocity Impact

Multilayer honeycomb sandwich structures are widely employed in engineering applications requiring high impact resistance. Nevertheless, the combined effects of key geometric parameters on their low‐velocity impact performance and deformation mechanisms remain insufficiently understood. In this study, the low‐velocity impact behavior of multilayer honeycomb sandwich structures is investigated using combined experimental and numerical approaches under different impact energy levels, focusing on the effects of face sheet thickness, core wall thickness, and core height on impact response, deformation characteristics, and failure evolution. The results indicate that the impact responses can be classified into three distinct modes: multipeak, single‐peak, and plateau‐type responses. The multipeak mode is dominated by sequential perforation of face sheets and core layers, the single‐peak mode is governed by cooperative deformation among multiple face sheets, and the plateau‐type mode is characterized by global bending with extensive core crushing. Further analysis based on impact efficiency reveals clear parameter‐dependent trends. Increasing face sheet thickness enhances cooperative load‐bearing capacity and stabilizes impact resistance at higher energies, whereas reducing core height improves impact efficiency at low energies but increases energy sensitivity. These findings clarify the interplay between structural parameters and impact resistance mechanisms, offering guidance for the design of multilayer honeycomb sandwich structures.