Snap-fit mechanical metamaterials

Reusability and multi-functionality are challenges in the design of energy-absorbing structures, which may realize through special metamaterials. Multistable mechanical metamaterials with different energy barriers are one of the most promising candidates to achieve this goal. Here, a novel snap-fit based modular multistable mechanical metamaterial was proposed for energy absorbing, together with reprogrammable, reconfigurable and reusable properties. The multistable states of metamaterials was achieved by connecting the snap-fit units in series and the modular design was realized with the mechanical response decoupling of these assembled units connected in parallel. The mechanical performances of single snap-fit unit and metamaterials are theoretically, numerically and experimentally investigated. It is evident that the designed metamaterials exhibit excellent impact resistance and energy absorption capacity in the demonstrative experiments, which can be considered as a potential candidate in the development of shock absorbers. The metamaterials can also be adapted to different non-planar protectors with flexibly deployed and easily replaced in complex environments. This strategy provides new mentality and methods for the design of reusable impact protection devices, material constitutive simulators, mechanical information storage and logic gates, robots and many other fields and devices.