Research on design and applications of multistable mechanical metamaterial structures with high fatigue resistance

In this study, we develop a multistable tensegrity-inspired auxetic metamaterial to address the limited durability, restricted deformation modes, and poor self-recovery commonly observed in conventional negative Poisson’s ratio structures. The proposed design is based on a regular quadrilateral unit cell composed of rigid sliding rods, compression springs, and elastic tensile elements, forming a self-equilibrated configuration with a central rigid core and a surrounding tensile network. This architecture enables synchronized longitudinal contraction and transverse expansion, resulting in an equivalent Poisson’s ratio close to −1 and a highly isotropic deformation pattern. Quasi-static compression tests show a clear three-stage force–displacement response, with programmable stiffness and tunable energy absorption ranging from 93 mJ to 313 mJ. After 1000 loading–unloading cycles, the energy dissipation capacity decreases by only 9.03%, indicating stable fatigue performance. Assemblies consisting of 4, 6, and 9 unit cells preserve the essential mechanical characteristics of the single-cell structure. Moreover, impact tests demonstrate a reduction in peak force of 68.94%–78.49% and an approximately twofold increase in impact duration. These results suggest that the proposed metamaterial provides a practical and scalable solution for reusable impact-mitigation systems in aerospace, robotics, and protective engineering applications.