Design and analysis of a tunable multistable mechanical metamaterial

Multistable mechanical metamaterials can have unusual properties that facilitate promising applications, including reusable vibration isolation and efficient energy absorption. In this paper, we propose a tunable multistable mechanical metamaterial (TMMM) that is capable of independent and continuous adjustment of its post-fabrication mechanical properties. The unit cell of the TMMM consists of a sinusoidal beam and several supporting beams, with its mechanical behavior finely tuned by inserting specially designed connecting beams into the gaps of the supporting beams. We adopt a combined theoretical and numerical approach to explore the effect of geometric parameters and identify the design space of monostability and bistability. Based on the unit cell, a multilayer TMMM is designed and fabricated and its tunable mechanical response is investigated. The results show that not only the force-displacement curves but also the snap-through behavior and deformation order can be tuned in a straightforward manner. The proposed design has the potential to enhance the development of multistable mechanical metamaterials and broaden their applications in engineering scenarios with varying demands.