Observation of Squeeze–Twist Coupling in a Chiral 3D Isotropic Lattice

A chiral 3D lattice is designed, made by 3D printing, and studied experimentally. The lattice exhibits squeeze–twist coupling and a Poisson's ratio near zero. Squeeze–twist coupling does not occur in classical elasticity which makes no provision for chirality. By contrast, chiral effects are allowed in Cosserat elasticity. An experimental squeeze–twist coupling strain ratio on the order of unity and a Poisson's ratio near zero are in reasonable agreement with prior finite element analysis of a lattice with similar structure, for which negative Poisson's ratio is anticipated for a sufficient number of cells. A chiral lattice is designed, made, and studied experimentally. Chiral materials have an asymmetry that distinguishes left‐ and right‐handed forms. They are well known in chemistry and in biology. Classical elasticity makes no provision for chirality. Observed chiral effects such as squeeze–twist coupling cannot be understood classically but are understood and predictable within Cosserat elasticity.