Fundamental Studies on the Development of Tensegrity Strutures

当连续旋转的缆索系统由在缆索系统的节点之间间歇地布置的压缩构件（连杆）支撑，并且每个构件通过延长压缩构件或缩短缆索构件而被预加应力时，则该系统可以是稳定的并且具有抵抗外部载荷的一定刚度。这是一种所谓的张拉整体结构。这种结构在土木工程建设领域还没有实际应用，我们的目标是找出这种系统在未来如何应用于土木工程建设领域。目前的研究目的是对结构分析进行基础性研究，以建立未来实用的设计分析方法。研究的概要如下：（1）强调了几何非线性大变形分析的必要性，并开发了相应的计算机程序。该程序是基于作者过去的研究工作的结果。(2)进行了各种数值算例研究，详细显示了结构在外荷载作用下的非线性特性，特别是在部分荷载或非对称荷载条件下。从而明确了线性理论的应用范围。(3)由于该结构的高度非线性特性，在实际的设计计算中，形状确定分析是必不可少的。为此，我们利用作者过去关于索结构理论的研究成果，发展了张拉整体结构的形状确定方法，形状确定分析的结果表明张拉整体结构对形状确定计算的高度敏感性。(4)通过一个简单的设计模型，利用通用的数值计算结果，验证了这种结构的适用性或可行性。

When a continuously spun cable system is strutted by compressive members (links) arranged intermittently between the nodes of the cable system and each member is prestressed either by lengthening the compressive members or by shortening the cable members, then this system can be stable and has some stiffness against external loads. This is a so-called tensegrity structure.This kind of structure is not yet practical in the field of civil engineering construction and we are aiming at finding out how this system can be applicable there in the future.The present purpose of the research is to make a fundamental investigation as to structural analysis for establishing the practical method of design analysis in the future.The outline of the research is as follows :(1) The necessity of geometrically nonlinear large deformation analysis is stressed and a computer program was developed for this purpose. The program is based on the results of the authors' past research works.(2) Various numerical case studies were conducted and nonlinear characteristics of the structure under external loads are shown in detail, especially under partial loading or non-symmetrical loading conditions. The limit of application of linear theory is thus made clear.(3) Owing to the highly nonlinear nature of the structure, it is obvious that the shape determination analysis becomes indispensable for the practical design calculation. For this purpose we developed the method of shape determination of tensegrity structure, by exploiting the authors' past results as to the theory of cable structures.The results of shape determination analysis show the high sensitivity of tensegrity structure against shape determination calculations.(4) The applicability, or feasibility, of this kind of structure was checked by a simple design model by using versatile numerical results.