A novel metamaterial incorporating both auxeticity and thermal shrinkage

Abstract

This work proposes a novel metamaterial incorporating the auxeticity and thermal shrinkage by originally introducing a bi-material double-square into the star-shaped configuration. The theoretical modeling based on Mohr's theorem was built to predict its elastic and thermal properties. It shows excellent consistency with the numerical results, including the homogenized Young's modulus, Poisson's ratio, and coefficient of thermal expansion in three principal directions. The influence of the geometrical topology and material parameters on the elastic and thermal responses was clearly identified. The results suggest that desired properties of the metamaterial can be customized by reasonably modulating the appropriate geometric and material parameters. Compared with the orthogonal-isotropic star-shaped metamaterial with identical relative density and dimension, the design proposed in this study exhibits significant advantages in the auxeticity and thermal shrinkage. The plastic investigation suggests that this metamaterial also shows auxetic properties in large deformation. This metamaterial incorporating auxeticity and thermal shrinkage can be expected for applications such as smart actuators and satellite antennas with thermal stability.