Development and investigation of novel negative stiffness metamaterial based on ring-shaped elastic deformation element

Abstract In the last few years, the concept of mechanical-type negative stiffness metamaterial (NSM) has gained greater attention and developed into an emergent field of research, partly due to advancements in additive manufacturing technologies that enable rapid fabrication of materials. In this work, a versatile bistable unit cell design is proposed, which exhibits large deformation. A theoretical model is developed and verified with experimental testing to accurately estimate the snap-through behaviour of the unit cell. The bulk of the theoretical model findings fall within a 10% range of the experimental results. This study demonstrates that the theoretical model proposed is accurate in its ability to predict the snap-through transition. Furthermore, a methodical parametric investigation is conducted into how geometric factors affect the snap-through characteristics. By adjusting the geometrical parameters of the unit cell, the required mechanical behaviour of the NSM may be tailored for specific applications. Finally, a 2D NSM lattice structure is developed, which exhibits multistability, tunable deformation, and a deterministic deformation sequence. These tunable behaviours can be controlled by setting proper values for geometrical parameters across the lattice. This study contributes to the design, development, and manufacture of tunable NSM and multistable structures.