Influence of Spacer Fabric Reinforcement on Mechanical Properties and Failure Mechanism of Sandwich Structure

ABSTRACT Traditional sandwich composites are prone to delamination failure when bearing loads. In order to solve this problem, woven spacer fabrics with binder yarn spacing of 10, 16, and 20 mm and heights of 20 and 40 mm were designed and woven, and sandwich composites with polyurethane foam‐filled polyester woven spacer fabrics were prepared. The results show that the peak impact loads of 1–2 (spacing of 10 mm, height of 20 mm), 1.6–2, and 2–2 are 1449.77, 1266.08, and 1259.39 N, respectively, which are increased by 26.0%, 10.0%, and 9.5% compared with the traditional sandwich materials; the bending stiffness increased by 40.7%, 32.8%, and 45.1%. After the impact of spacer fabric reinforced composites (SFRC), the loss rate of bending stiffness of the middle area (< 70%) and side samples (< 21%) is less than that of Plain. With the increase of the binder yarn height, the impact energy absorption efficiency can reach 85%; the impact resistance and bending properties are significantly improved. Furthermore, the failure mechanism of bending damage is studied by combining acoustic emission and digital image correlation; the SFRC improves the delamination phenomenon and shows promising applications in architecture, transportation, and aerospace.