Topological Changes in the Tetrachiral Metamaterial's Structure and Their Impact on Its Effective Properties

Metamaterials are structures whose elements have a particular geometry and consist of conventional (base) materials. Their properties can be influenced; in the present paper, changes in chirality of the sample walls considered as a topological transformation of the structure are used. Under uniaxial loading of the considered metamaterial, the force applied to the upper face is transferred to perpendicular walls, that begin to deform and rotate. This leads to rotation of the upper sample face. Based on the finite-difference equations, the effective strains and rotation of the upper face of the sample were calculated, and it was confirmed that rotation often dominates. However, for some cases the face experienced shear. It was found that the support reaction is directly related to the effect of the sample twisting. The results of our research demonstrate that the primary benefit of metamaterials is that their mechanical properties can be controlled by changing the structure geometry.