4D Pixel Mechanical Metamaterials with Programmable and Reconfigurable Properties

Abstract

Abstract The tension‐torsion coupling metamaterial (TTCM) exhibits torsional deformation while stretching, with the degree of freedom exceeding the Cauchy elasticity. However, the TTCM suffers from the limitations of the weak tension‐torsion coupling effect (TTCE), narrow deformation domain, and lack of adaptability. To address these limitations, mechanical pixel (MP) array design, helical microstructure, and 4D printing are introduced into the TTCM in this study, providing new strategies to exploit the deformation potential of the TTCM. The developed MP exhibits the tunability, programmability, and reconfigurability of the mechanical behaviors (stress–strain relationship, TTCE). The pixel mechanical metamaterial (PMM) with uncoupled deformation between MPs is obtained, which greatly enriches the design diversity of configurations and maintainability. The application prospects of the developed PMM for information encryptions, kinematics controllers, soft robots, and buffer devices are demonstrated. More interestingly, an egg falling on the PMM at the height of ≈1 m remains intact due to the excellent protection performance of the PMM.