Mechanical properties of multifunctional auxetic sandwich box-shaped structures

Abstract The construction industry is rapidly evolving towards intelligence. The emergence of multifunctional metamaterials aligns with this trend. This paper introduced a novel 3D re-entrant sandwich box structure (Re-box). A mesh sandwich box structure (Me-box) was designed as a control group to analyze the differences between positive and negative Poisson’s ratio sandwich cores. The structure’s energy absorption (EA), durability, and acoustic characteristics were studied. Experimental and FEA results demonstrate the Re-box’s superior EA capabilities. Notably, the Re-box maintained excellent stiffness under cyclic loading. Furthermore, the Re-box proposed in this study achieved nearly perfect sound absorption in the mid-to-low frequency range. Therefore, the structure provides protective functions while simultaneously reducing ambient noise levels. Compared with traditional concrete structures, the proposed Re-box in this paper serves mechanical-acoustic functions. It achieves both lightweight design and effective control of sound waves. The Re-box structure can be used as a protective device for the internal structures of aircraft and automobiles through an assembly and combination approach.