Modeling and Dimensional Optimization of a Novel 3D Mechanical Metamaterial with Tunable Coefficient of Thermal Expansion

The tunable thermal expansion of mechanical metamaterials is conducive to solve the problem of structural thermal deformation caused by drastic temperature changes. Based on our previous work on 2D metamaterial with tunable coefficient of thermal expansion (CTE), this paper proposes a 3D metamaterial structure that can changes its equivalent CTE. Based on the 3D beam element theory, the thermoelastic model for the structure under the coupling effect of temperature and external load is established. Simulations about CTE and elastic modulus are carried out to verify the theoretical modeling. The influence of geometric parameters and material combinations on the properties of the mechanical metamaterial are revealed. The multi‐island genetic algorithm (MIGA) is used in dimensional optimization, which results in 3D mechanical metamaterial with good stiffness and a prescribed CTE range.