Mechanical Metamaterials

Auxetics for stiffness control

The unique negative Poisson behavior of the auxetic structure affects the static properties of the structure. Our group has aimed at applying auxeticity to the conventional structure to control the static characteristics. We are studying stiffness control of tube structure with auxetic slit and instability-induced auxetics with zero stiffness. An auxetic slit pattern is made using a rotating unit structure, which is a typical auxetic structure, and an auxetic tube is made by inserting it into a tube structure. Controls the shape of the slit pattern of the auxetic tube to independently control the bending and torsional stiffness of the tube structure. Periodic patterns of structures can cause auxetic deformation patterns under compressive loads upon reaching a critical load, which induced sudden deformation without load increase, or zero stiffness. Our group has aimed at finding a critical value of compressive loads and controlling the range of zero stiffness of structures.