A New Family of 3D Auxetic Mechanical Metamaterials with High Resilience and Elastic Hysteresis

A new family of high resilient 3D auxetic mechanical metamaterials are designed. The new designs show remarkable resilience under large deformation together with significant hysteresis under cyclic compressive loading-unloading. Both isotropic and anisotropic designs are created. The 3D isotropic design shows ideal isotropy with negative Poisson’s ratio close to -1 in all loading directions, as rarely seen in existing mechanical metamaterials. Also, the anisotropic mechanical properties including the effective stiffness and effective Poisson’s ratio can be tuned in a wide range. In addition, new designs can also show a unique simultaneous twisting and shrinking behavior under uni-axial compression. An integrated experimental, analytical and numerical approach is applied to quantify the effective mechanical properties of the new designs. Systematic FE simulations and analytical analyses are performed. The new designs are also fabricated, and mechanical experiments were performed on selected designs. These novel properties make 3D keyed-brick mechanical metamaterials be a potential candidate as engineering material with unique properties beneficial from negative Poisson’s ratio, damping material for energy absorption, impact resistant material under special loading conditions.