Effect of the Type of Unit Cell Connection in a Metamaterial on Its Programmable Behavior

In this work, samples of a mechanical metamaterial with tetrachiral topology were studied by mathematical modeling. Two types of unit cell connections in the metamaterial were considered: adjoining and overlapping. The adjoining method led to the formation of double-thickness internal walls in the sample, which were considered to be topological defects in the metamaterial. The mechanical response and effective properties of the metamaterials were determined and analyzed by numerical simulations of the uniaxial loading. The results showed that the sample with higher effective density exhibited a more compliant (i.e., a more pronounced) load-induced twisting effect and a lower effective Young's modulus. The results obtained can be used in the design of metamaterials with programmable properties.