The Annular Open-Web Cable Truss Structure And The Achievement Of Load Relieving

Load Relieving System is a new type of structure system, which was put forward by a British scholar in 1980's. Its basic conception is that the structure achieves self-adjustment and self-protection by introducing some kind of movable device. Taking Annular Open-web Cable Truss Structure as the subject investigated, the property of this structure is studied, and the realization of load relieving based on this structure system is analyzed.Initial equilibrium state of Annular Open-web Cable Truss Structure is studied at first. By using the singular-value-decomposition method, the self-equilibrium stress mode is obtained, thereby the distribution of the pre-stress is found. Based on these, the geometric nonlinear analysis of this structure system is carried out by using commercial FEM program. The influence of the pre-stress on the static property is also presented. The results show that the stiffness of the linear elastic structure develops with the increase of pre-stress.The free vibration property of this structure as well as the parameter analysis is studied. It is obvious that structural pre-stress has very important effect on its frequency. Moreover, increasing the number of support can enhance the structural lateral stiffness, and improve the free vibration frequency. To get its seismic property of annular cable-truss structure without support, the time history analysis is completed. The results show that with the pre-stress growing, the structural displacement peak decreases, while the structural inner force change peak differ little.Load relieving of the structure is achieved by introducing the rigidity-modulating analysis method. The static property of the structure is studied. Moreover, the static properties of the structure are compared, when elastic modulus decreases by using different functions. The results show when the elastic modulus decreases faster, deformation of the structure is larger. On the contrary, the improvement of inner force of components is slower. It is noticed that the condition of inner force decreasing even appears. As a result, it is feasible that load relieving of the structure is achieved byapplying the rigidity-modulating method theoretically.Finally some conclusions are summarized and the problems that should be studied further are put forward.