Improved compression-torsion conversion in geometrically optimized mechanical metamaterials

Three-dimensional chiral metamaterials exhibit twisting motion under axial loadings. This paper deals with the compression-torsion behavior of the unit cell of a Three-dimensional mechanical metamaterial composed of two square lattices chirally connected by four tilted rods. Particularly, the effect of the geometrical shape of the lattices on the torsion is investigated using finite-elements simulations. It is shown that an optimized configuration can be reached under specific conditions. We further lead an elasto-dynamic study in which we put forward the torsion motion identified throughout an analysis of band structures. This type of metamaterials may open interesting avenues towards elastic modes' conversion and sensing.