A novel strategy to design lattice structures with zero Poisson's ratio

Cellular metamaterials are man-made structures that have unusual mechanical properties. Microlattice structures belong to a category of cellular metamaterials formed by periodic arrangement of interconnected struts or plates. The Poisson's ratio of a microlattice structure can be tuned for a specific application by tailoring the unit cell parameters. In this work, lattice structures exhibiting zero Poisson's ratio were designed by mimicking composite materials in which a positive Poisson's ratio exhibiting lattice was incorporated as reinforcements in the matrix of a negative-Poisson's-ratio lattice structure. Numerical simulations were conducted to study the quasi-static mechanical behavior of the proposed zero-Poisson's-ratio structures, and the results were corroborated with experiments. The elastic moduli as well as Poisson's ratios obtained from numerical and experimental results were within the limits of the conventional rule of mixture for composite materials. These composite-materials inspired lattices with zero Poisson's ratio resulted in superior mechanical properties than three commonly studied zero Poisson's ratio structures found in previously published literature. Thus, the proposed strategy of improving the mechanical properties of zero Poisson's ratio lattice structures using a reinforcement lattice can be more promising than the conventional method of tuning the unit cell geometry of a zero Poisson's ratio lattice.