Static Analysis And Stiffness Regulation Of Two-stage Three-bar Tensegrity Prism

Tensegrity structure is a stable structure composed of a set of discontinuous compression members and a set of continuous tension members. Its beautiful shape, light mass, foldable structure, unique mechanical properties and in line with the natural characteristics of creatures, has made tensegrity a great potential in application of many different fields in recent years. Based on it`s similarity of organism’s characteristics and its important potential applications. This project take the three-bar tensegrity prism structure as an example, by studying its description, form-finding analysis, static analysis and stiffness analysis and regulation to further study the nature of tensegrity structure and lay the theoretical foundation and try to find effective methods for future application of tensegrity structure and pave the way for further study.Firstly, this paper funded the self-equilibrium form of tensegrity structure based on the Monte Carlo form-finding method. Tensegrity structure can only be accurately described by the connectivity matrix and nodal coordinates. Depart from tensegrity prisms, according to its topology and by programming the connectivity matrix can be automatic written for arbitrary stage multi-prism tensegrity prisms. Taking advantage of the basic idea of Monte Carlo form-finding method, tensegrity prisms form can be obtained in an effective way, and it can reveal the equilibrium of tensegrity, laid the foundation for further analysis.Secondly, by the method of singular value decomposition, the static analysis of tensegrity structure can be solved, and a static analysis method suitable for engineering and technical personnel has been explored. In case of small displacements, static balanced matrix has dual properties of statics and kinematics, which makes the unit forces and nodal displacements, can be obtained by the method of singular value decomposition. However, since the tensegrity is not only statically indeterminate but also kinematically indeterminate, its static analysis must take compatible equation and displacement mechanism into consideration. While, in case of large displacement, finite element analysis software is more suitable for static analysis.Finally, the stiffness matrix of tensegrity structure is analyzed, and stiffness regulation has been studied. The Stiffness of tensegrity comes from two parts, one is linear stiffness consisted of the configuration and material properties, another is geometric stiffness related with internal force. By changing the internal force of members the geometry stiffness can be changed, so the stiffness of the whole structure can be regulated.