Multifunctional mechanical metamaterials with tunable double-negative isotropic properties

• Published in: Materials & design Vol. 232; p. 112146
• Main Authors: Li, Zuyu, Gao, Wei, Kessissoglou, Nicole, Oberst, Sebastian, Wang, Michael Yu, Luo, Zhen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2023; Elsevier
• Subjects: Elastic isotropy; Multi-material lattices; Negative Poisson’s ratio; Negative thermal expansion; Topology optimization; Tunable properties; Topology optimization; Multi-material lattices; Negative Poisson’s ratio; Elastic isotropy; Negative thermal expansion; Tunable properties
• ISSN: 0264-1275
• DOI: 10.1016/j.matdes.2023.112146

[Display omitted] •Propose a new multi-material topology optimization method for designing three-dimensional strut-based metamaterials•Develop novel microstructures with elastic isotropy, negative thermal expansion coefficients and negative Poisson’s ratios•Achieve tunable double-negative isotropic properties by altering the cross-sections or the material combination of struts•Demonstrate the effective properties of the optimized metamaterial designs through numerical simulations This research was focused on innovative design of lattice metamaterials that can exhibit tunable double-negative mechanical properties and elastic isotropy simultaneously. A discrete topology optimization method using a multi-material ground structure was developed to create microlattices exhibiting both negative thermal expansion coefficient and negative Poisson’s ratio in a single integrated design, while maintaining elastic isotropy. First, the numerical homogenization method with beam elements was used to estimate the effective thermal and elastic properties of a microlattice. Second, the topological design, subject to required geometric constraints, was formulated as a mixed integer programming problem to discover a series of multi-material microlattices that present customized isotropic values of negative thermal expansion coefficient and negative Poisson’s ratio. Finally, several three-dimensional multi-material microstructures were produced by altering either the cross-sections or constituent materials of struts to demonstrate their tunable mechanical properties.