含冗余拉索的张拉整体拼接结构变形能力分析

Analysis of shape-change capabilities of tensegrity structures with redundant cables

摘要:

为研究含冗余拉索的张拉整体结构的变形能力,基于能量耗散最少的索驱动理念,提出了实现结构变形的最优驱动方式的选择方法。首先,对张拉整体基本单元的结构参数、构件与节点的连接关系进行设置,并对索长收缩后结构新的稳定状态进行力学性能分析,得出新的节点坐标计算公式；其次,赋值结构参数和材料参数,对结构的变形过程进行分析:先收缩被动索对张拉整体结构进行预紧,计算除主动索外结构额外耗散的弹性势能,后收缩主动索使张拉整体结构发生变形,计算主动索能量耗散做功和结构的最终变形,提出结构变形的最优驱动方式的评价标准；最后,以含冗余拉索的双层轴向拼接结构为例,区分结构的主动索与被动索,进行最优驱动方式研究。分析结果表明:对于结构的单一轴向变形,当斜索为主动索、中间水平索为被动索时,结构的轴向变化最大,能量耗散最小；对于包含轴向变形与扭转变形的结构复合变形,当与杆构件旋向相反的斜索为主动索,剩余斜索为被动索时,结构的复合变形最大,能量耗散最小。

Abstract:

To study the deformation capacity of tensegrity structures with redundant cables, this paper proposed a method to select the optimal driving mode to achieve structural deformation based on the cable-driven concept with minimal energy dissipation. Firstly, the structural parameters of the tensegrity basic unit and the connection relationship between the member and the node were set, and the mechanical properties analysis was conducted on the structure in the new stable state after the contraction of the cable. This analysis yielded a new calculation formula of the node coordinates. Secondly, the structural parameters and material parameters were assigned to analyze the deformation process of the structure. The passive cables was firstly shrunk to prestress the tensegrity structure, and the additional dissipated elastic potential energy of the structure except for the active cables was calculated. Then, the active cables was shrunk to induce the deformation of the tensegrity structure. The energy dissipation work of the active cables and the final deformation of the structure were calculated. Moreover, the evaluation criteria of the optimal driving mode of the structural deformation were proposed. Finally, taking the double-layer axial splice structure with redundant cables as an example, the active and passive cables of the structure were differentiated and the optimal driving mode was studied. The results show that for the single axial deformation of the structure, when the diagonal cables are active and the middle horizontal cable is passive, the axial change of the structure is maximized while the energy dissipation is minimized. For the composite deformation involving axial deformation and torsional deformation, the composite deformation of the structure is maximized and the energy dissipation is minimized when the diagonal cables opposite to the rod member are active while the remaining diagonal cables are passive.