Magnetically Assisted Rotationally Multistable Metamaterials for Tunable Energy Trapping–Dissipation

Abstract A motif for rotational multistability is developed by arranging permanent magnets in a circular pattern and creating magnet pairs with magnetically induced negative incremental torsional stiffness. Through a set of experimental and numerical studies, different means to tailor the torsional response of a rotational magnet pair are demonstrated. A magnet pair in tandem with tilted elastic arms is harnessed to form an energy‐trapping rotational unit cell. By stacking several of these unit cells upon each other, a 1D rotationally multistable metamaterial capable of storing the input energy and releasing it in the form of rotational waves is developed. The periodic stable equilibrium states in rotational magnet pairs invoke the notion of cyclic multistability, which is employed here to realize, for the first time, a tunable fluid‐free rotary metadamper with energy dissipation induced by repeating snap‐back instabilities. High tunability of magnetic interactions offers a new design paradigm for developing reusable energy dissipative and energy trapping rotary metamaterials, the properties of which can be easily tailored in situ and even at the post‐fabrication stage.