A study of global cable force identification of tensegrity structures

Based on the self-balancing property of tensegrity structures, this paper presents a cable force identification method that can be used to simultaneously identify the cable forces of all cables of a tensegrity structure solely by measuring the forces in one or a few members. First, based on the self-stress modes of tensegrity structures, the relationship of forces among members is established in order to reduce the amount of identification parameters and enhance the likelihood of finding an efficient solution. Next, the optimization model of identifying the internal force of all elements is established, and the optimization problem is solved by use of an improved self-adaptive decimal coding genetic algorithm (GA). Then the theoretical feasibility of the method is verified by numerical simulation analysis. The influence of model error and test error on the accuracy of the identification results is also investigated. The results show that the proposed method has good numerical stability, and the synchronous identification of cable forces for all cable segments can be realized only by measuring the cable forces of a few cable segments or the pressures of a few compression bars, which greatly improves test efficiency and provides a new idea for the cable force identification of tensegrity structures as it is much easier to measure the internal force of bars than cable force. In this paper, a general finite element program is established based on Matlab language, and a provided example shows that the method can be extended to other cable-strut tensile structures.