Numerical analysis of the effective thermal properties and the stability for NTE metamaterials using CAE fidesys

Abstract

Metamaterials are composite materials, the properties of which are determined primarily by their geometric cellular microstructure, and not by the properties of the components included in their composition. The article is devoted to the metamaterials with a negative thermal expansion coefficient (NTE). The thermal expansion effective coefficients of such materials are analyzed. Effective thermal expansion is calculated numerically, by solving a boundary value problem of thermoelasticity on the metamaterial's periodicity cell using finite element method. A strain tensor is averaged over the cell. Effective thermal properties are estimated using the averaged solution results. Also, a stability of NTE-metamaterial's cell under thermal loads is analyzed. The article presents a dependency of the metamaterial effective thermal expansion coefficients on various geometric parameters of its cell. Variation of these parameters allows to make the thermal expansion effective coefficient both zero and negative with a large absolute value. A metamaterial is proved to be stable under thermal loads in a wide range of temperatures.