Controlling mechanical response of tetrachiral metamaterials through topological transformations

In this study, the mechanical behavior of a metamaterial with a tetrachiral structure was investigated using mathematical modeling. Topological transformations (defects) were introduced into the metamaterial architecture, leading to modifications of its properties under uniaxial loading. The relative density of all samples was 84.9 %. The tetrachiral structure is of particular interest due to its ability to exhibit unconventional behavior, namely the load–twist coupling effect, and its influence on the force reaction. Twisting was evaluated by deflections of the sample top face vertices. Among all metamaterial configurations, the maximum deflection was observed in the sample with the topological transformation x4 and reached 8.1 mm, whereas the minimum deflection was recorded for x123 and equaled −7.9 mm. The force reaction is closely associated with the twisting of the sample. The maximum value was determined for configuration x1345 and amounted to 32.2 kN, while the minimum value was obtained for configuration x45 and equaled 24.5 kN. Thus, the transition from periodic to non-periodic architectures represents an effective strategy for tailoring mechanical characteristics and achieving controllable anisotropy. Based on the analysis of the obtained results, predictions of mechanical behavior under additional topological transformations were formulated. The prediction success rate was found to be 0.5. Unsuccessful were predictions aimed to decrease the deflection and to increase the support force reaction.

1. Russian Science Foundation - Grant No. 25-29-01182, https://rscf.ru/en/project/25-29-01182/