3D Programmable Metamaterials Based on Reconfigurable Mechanism Modules

Mechanical metamaterials are of tremendous research interest due to their unconventional properties that arise from unit microstructure. Shape‐reconfiguration is an effective method to realize programmability on various properties for different tasks of a structure or system, while existing researches focus on multiple degree‐of‐freedom (DOF) systems or limited configurations that morph along a single kinematic path. Here, starting from a one‐DOF Wohlhart polyhedron module, its interesting topological transformation is explored along multiple motion paths through kinematic bifurcations, accompanied by tunable mechanical properties, including Poisson's ratio, chirality, and stiffness. Furthermore, these modules are tessellated into 3D metamaterials to harness their reconfigurability to independently program the Poisson's ratios in orthogonal planes within a wide range of negative Poisson's ratio, positive Poisson's ratio, and even zero Poisson's ratio. This work opens up avenues for the design of programmable metamaterials based on the perspective of kinematic bifurcation generating from single DOF systems, which can readily be applied in shape‐morphing systems in various fields, such as flexible metamaterials, morphing architectures, and deployable structures. A one‐degree‐of‐freedom reconfigurable module exhibits distinct topological transformation along multiple motion paths, accompanied by tunable mechanical properties, including Poisson's ratio, chirality, and stiffness. The modules are tessellated into 3D metamaterials to harness their reconfigurability to independently program the Poisson's ratios in orthogonal planes within a wide range of negative, positive, and even zero Poisson's ratios.