Low‐Velocity Impact Response and Damage Mechanisms of Fiber Metal Laminate/PMI Foam‐Reinforced Corrugated Sandwich Structures

This study aims to analyze the low‐velocity impact behavior of fiber metal laminate/PMI foam‐reinforced corrugated sandwich structures (FPCS) under three energy levels (25, 55, and 85 J) and front/reverse impact configurations (FPCS‐F/R) through combined experimental and numerical approaches. The dynamic response and failure mechanisms during low‐velocity impacts are revealed based on load histories, energy absorption characteristics, and failure morphologies obtained from impact tests. Through comparative analysis with foam‐free (FCS‐F/R) and pure foam‐filled (PCS‐F/R) structures, the influence mechanisms of foam filling and impact orientation on impact resistance are elucidated. Meanwhile, a numerical simulation model for predicting the low‐velocity impact behavior of structures was developed and validated based on a user subroutine, which considered progressive damage modes such as aluminum alloys, foams, composites, and interfaces. Results demonstrate significant effects of foam filling and impact orientation on dynamic response and load‐bearing capacity. At 25/55/85 J impacts, FPCS‐F specimens achieve 72.5%, 66.2%, and 89.4% higher peak loads than FCS‐F counterparts, with 74.8%, 39.3%, and 8.5% improvements over FPCS‐R specimens, respectively.