A re-usable negative stiffness mechanical metamaterial composed of Bi-material systems for high energy dissipation and shock isolation

Mechanical metamaterials with negative stiffness (NS) effects are able to dissipate mechanical energy repeatedly according to the "snap-back" strategy. Nevertheless, the strategy is merely efficient when a plethora of NS cells are lined together in series. Limitations of the strategy bring challenges to ameliorate the capacity of energy dissipation for the NS. In the present research, an unique re-usable NS mechanical metamaterial made up of Bimaterial systems was suggested and fabricated, which is able to dissipate energy even supposing such metamaterial was merely made up of a single unit. To get a thorough knowledge of the metamaterial's quasi-static mechanical characteristics, a combination of loading-unloading experiments and finite element method (FEM) has been conducted. The effects of structural arguments on the mechanical characteristics were then revealed employing the experimentally authenticated numerical model. The metamaterial possesses outstanding reusability and a large capacity for energy dissipation, according to the findings of quasi-static tests. Finally, plate-impact tests were executed to explore the cushion performances of this metamaterial. The presented Bimaterial NS mechanical metamaterial demonstrated notable potential in energy dissipation and shock isolation.