Li Yanbin, Zhou Caizhi, Yin Jie
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27606, USA.
Philos Trans A Math Phys Eng Sci. 2024 Oct 7;382(2283):20240010. doi: 10.1098/rsta.2024.0010.
We explore a new design strategy of leveraging kinematic bifurcation in creating origami/kirigami-based three-dimensional (3D) hierarchical, reconfigurable, mechanical metamaterials with tunable mechanical responses. We start from constructing three basic, thick, panel-based structural units composed of 4, 6 and 8 rigidly rotatable cubes in close-looped connections. They are modelled, respectively, as 4R, 6R and 8R (R stands for revolute joint) spatial looped kinematic mechanisms, and are used to create a library of reconfigurable hierarchical building blocks that exhibit kinematic bifurcations. We analytically investigate their reconfiguration kinematics and predict the occurrence and locations of kinematic bifurcations through a trial-correction modelling method. These building blocks are tessellated in 3D to create various 3D bifurcated hierarchical mechanical metamaterials that preserve the kinematic bifurcations in their building blocks to reconfigure into different 3D architectures. By combining the kinematics and considering the elastic torsional energy stored in the folds, we develop the geometric mechanics to predict their tunable anisotropic Poisson's ratios and stiffnesses. We find that kinematic bifurcation can significantly effect mechanical responses, including changing the sign of Poisson's ratios from negative to positive beyond bifurcation, tuning the anisotropy, and overcoming the polarity of structural stiffness and enhancing the number of deformation paths with more reconfigured shapes.This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'.
我们探索了一种新的设计策略，即利用运动学分支来创建基于折纸/剪纸的三维（3D）分层、可重构、具有可调机械响应的机械超材料。我们从构建三个基本的、厚实的、基于面板的结构单元开始，这些单元由4个、6个和8个刚性可旋转立方体以闭环连接组成。它们分别被建模为4R、6R和8R（R代表旋转关节）空间闭环运动机构，并用于创建一个可重构分层构件库，这些构件表现出运动学分支。我们通过试错校正建模方法对它们的重构运动学进行了分析研究，并预测了运动学分支的发生和位置。这些构件在3D中进行镶嵌，以创建各种3D分支分层机械超材料，这些超材料在其构件中保留运动学分支，以便重新配置成不同的3D结构。通过结合运动学并考虑褶皱中存储的弹性扭转能量，我们发展了几何力学来预测它们可调的各向异性泊松比和刚度。我们发现运动学分支可以显著影响机械响应，包括在分支之后将泊松比的符号从负变为正、调整各向异性、克服结构刚度的极性以及通过更多重新配置的形状增加变形路径的数量。本文是主题为“受折纸/剪纸启发的结构：从基础到应用”的一部分。
