Optimization Research On The Supportting Structure Of Fast Refelector

In 1994, some chinese astronomers proposed building a five-hundred-meter aperture spherical telescope (FAST) with an active reflector in the Karst terrain of Guizhou Province , China, which will be the largest and most powerful radio telescope in the world. So far a suitable supporting structure of the reflector has not been decided in earlier research due to the nature of large aperture, complexity of the Karst terrain and the difficult activation of the reflector.In previous research on FAST by the Space Structure Research Center , HIT, an efficient support structure of reflector was proposed which consists of cable-net and steel sub-structure; the patterns and sizes of cable mesh, as well as locations of controlling cables have been investigated respectively to find out the best set of some key parameters. Some valuable results and information have been obtained. In this paper, further research on FAST is undertaken; the proposed support structure of reflector is improved and optimized.Optimizing the system for the previous scheme from diagrammatic of lattice,input mode of initial calculation stress and strategy of displacement shift. The optimization of the cable-net is performed to reduce the level of stress, which leads to lower cost of construction. Meanwhile, the characteristics of cable-net under various loads (self-weight of sub-structures and temperature) are studied and the influence of load on response of cable-net is quantified.The effect of boundary support on cable-net is taken into account. A latticed boundary support is developed and its effect on stress in cable-net during the process of objective-searching and under temperature action is discussed respectively.The shape precision of the reflector is analyzed comprehensively. A series of measures is taken to provide high precision in reflector shape in its working state.