Abstract Motion structures whose macroscopic topology can be controlled by an internal kinematic mechanism play a new role in the design of mechanical metamaterials. Motion structures with N-fold symmetry show a reconfigurable pattern transformation, providing tunable mechanical properties by topological reconfiguration, not by geometric reconfiguration. The objective of this work is i) to synthesize motion structures from a bar-and-joint framework and ii) to investigate their mobility and symmetry breaking during transformation together with nonlinear structural properties - modulus and Poisson's ratio, switchable stiffness, and bi-stiffness. Two-dimensional (2D) motion structures with N-fold symmetry (MS-N) are synthesized by central scissor links with revolute joints, connected with binary links in the radial direction. Five 2D motion structures - MS-4, MS-6, MS-8, MS-10, and MS-12, are constructed for investigating their mechanical properties together with their transformability. We build analytical models of motion structures on relative density, modulus, Poisson's ratio, and switchable stiffness as a function of transformation, verified with experiments and numerical simulations. By combining the kinematic mechanisms with structural mechanics, this study contributes to expanding the design space of reconfigurable metamaterials.

中文翻译：

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具有运动结构的拓扑可重构机械超材料

摘要 宏观拓扑结构可由内部运动机构控制的运动结构在机械超材料设计中发挥着新的作用。具有 N 重对称性的运动结构显示出可重构的模式变换，通过拓扑重构而不是几何重构提供可调节的机械特性。这项工作的目标是 i) 从杆和关节框架合成运动结构和 ii) 研究它们在转换过程中的移动性和对称性破坏以及非线性结构特性 - 模量和泊松比、可切换刚度和双刚度. 具有 N 重对称性 (MS-N) 的二维 (2D) 运动结构由具有旋转关节的中央剪式连杆合成，并在径向上与二元连杆相连。构建了五个 2D 运动结构 - MS-4、MS-6、MS-8、MS-10 和 MS-12，用于研究它们的机械性能和可变形性。我们根据相对密度、模量、泊松比和作为变换函数的可切换刚度建立运动结构的分析模型，并通过实验和数值模拟进行验证。通过将运动学机制与结构力学相结合，该研究有助于扩展可重构超材料的设计空间。通过实验和数值模拟验证。通过将运动学机制与结构力学相结合，该研究有助于扩展可重构超材料的设计空间。通过实验和数值模拟验证。通过将运动学机制与结构力学相结合，该研究有助于扩展可重构超材料的设计空间。