Tunable compression-torsion coupling effect in novel cylindrical tubular metamaterial architected with boomerang-shaped tetrachiral elements

Manipulation of cellular cylindrical tubes offers great opportunity to design functionalized materials and structures. In this study, inspired by the deformation mechanism of 2D perforated auxetic materials with peanut-shaped cuts, a new design for improving compression-torsion coupling (CTC) performance of tubular mechanical metamaterial is presented by introducing boomerang-shaped tetrachiral elements with curved ligaments, no longer limited to inclined straight ligaments. Static compression experiment and finite element simulation for the fabricated specimen by 3D printing reveal that the specimen exhibits promising CTC performance and the experimental results agree well with the numerical solutions. Moreover, the rotation angle of the tube approximately linearly increases with the increasing compression strain, except for the initial loading stage. Subsequently, the deformation mode of the present CTC tube is further illustrated by comparing to the existing CTC tubes including inclined straight ligaments. The curved ligament in the present design brings more flexible deformation than the straight one, and thus leads to better CTC property. Finally, the effects of controlling parameters on the CTC deformation are comprehensively analyzed to provide a deep understanding of the tunable design of compression-torsion tubular metamaterials for potential applications.