Quasi‐static mechanical properties of a modified auxetic re‐entrant honeycomb metamaterial

Auxetic metamaterials possess superior properties and have drawn extensive attention in the past decades. Herein, two curved ribs are added to the conventional re-entrant (CRE) honeycomb structure to form a modified auxetic re-entrant (MRE) honeycomb structure for improving the energy absorption capacity of the structure. In-plane quasi-static compression response of the honeycomb in large deformation is numerically explored first. Then, quasi-static compression test is conducted to verify the validity of the numerical simulation. Both experimental and numerical simulation results reveal that during the quasi-static compression process, two plateau stresses occur in the load-displacement curves of the structure, and the second plateau stress is much higher than the first one. The occurrence time of the second plateau stress can be controlled by the distance between the concave curved ribs in the structure. The experimental results are in good agreement with the finite element analysis results. Due to their desirable mechanical properties, the MRE honeycomb structures have great potential for applications in civil engineering, vehicle crashworthiness, and protective infrastructure.