Gradient metamaterials with tunable compression-twist coupling deformation

Abstract

Compression-twist metamaterials exhibit unique properties of compression-induced twisting, presenting new possibilities for the development of smart materials. However, achieving multifunctionality solely through conventional configuration design and parametric studies of individual cells is relatively constrained. Gradient metamaterials, which are characterized by continuous spatial variation in physical and mechanical properties through the gradient design of geometric parameters, offer a promising approach for development multifunctional and smart materials. In this study, a novel 3D gradient compression-twist metamaterial (GCTMM) is proposed, with its mechanical properties and deformation mechanisms under in-plane compression investigated by theoretical analysis, experiment, and numerical simulations. The experimental and simulation results demonstrate a nonlinear relationship between the twist angle and compressive displacement. The height and number of cell layers influence the overall stiffness of the GCTMM and affect the deformation coordination between layers. The structure’s compression-twist coupling properties are significantly reduced due to the plastic yield of the inclined rods. Analytical models were developed to describe the twist angle and initial yield displacement, accurately predicting the nonlinear variation in compression-twist coupling behavior and the degradation of the mechanical performance. To enhance structural reliability, an improved GCTMM with protective support columns was designed and analyzed through numerical simulations. The results indicate that the maximum stress within the structure remains below the material’s yield strength, ensuring its reliability and durability. These findings offer valuable insights for the design of gradient buffer materials, the development of mechanical signal enhancement or conversion devices, and the creation of multistage signal transmission sensors.