3D-Printed Nonuniform Lattice Metamaterials with Programmable Poisson's Ratio

This research presents a novel design method for mechanical metamaterials with programmable Poisson's ratio. Poisson's ratio of metamaterials can be quantitatively controlled by geometric parameters such as the side length of the rhombus, rhombus angle, and reentrant angle. The parametric study was conducted through finite element method (FEM) analysis, revealing the influence of geometric parameters on Poisson's ratio and nominal modulus. The FEM results have a good agreement with the experiments. Additionally, based on the design concept of nonuniform stiffness, we have designed different structural parameters for different areas to achieve multiple Poisson's ratio effects within the same structure. Ultimately, two types of nonuniform stiffness metamaterials, featuring distinct three Poisson's ratios and asymmetrical Poisson's ratios were obtained, respectively. This work expands the design methods in the research of programmable Poisson's ratio metamaterials and provides guidance for the design of nonuniform stiffness lattice structures with tunable Poisson's ratio.