Wind Induced Response Analysis Of Triangle Cable Network For Supporting FAST Reflector

FAST (Five-hundred-meter Aperture Spherical Telescope) is a major project of SKA in China, Iit's regarded as an "eye to the sky" in valley. The Cable Network for Supporting FAST Reflector is a tension structure. The main loads are self weight and wind load. The controlling factor of the cable structure is its stiffness, not strength.Wind load is the main load on FAST Reflector when it works. When Cable Network for Supporting FAST Reflector changes its form to a paraboloid needed, the normal deformation induced by wind should not be larger than 1mm.Since 1998,the steel structure research room of Tongji University has participated in the research of FAST. Comparing the tension cable structure with traditional rigid structural systems, the tension Cable Network system was chosen for the supporting structure of FAST reflector. Master Song found a quite reasonable structure form of the structure, and computed the average nodal displacement of the structure induced by wind in working state (paraboloid state).The Cable Network for Supporting FAST Reflector is a large-scale spatial structure, The response induced by fluctuating wind should not be ignored. A detail numerical analysis of the wind response of FAST Reflector structure is conducted in this paper.In the analysis, the Cable Network for Supporting FAST Reflector is simplified as linear system. An frequency domain method based on multi-mass vibration theory is used. The PSD (Power Spectral Density) method is used to analyze the wind response of the Cable Network.As is shown in this paper, fluctuating-wind induced nodal displacements are between 0～0.9446mm.The nodal displacements of paraboloid decreased gradually from the edge to the centtal area. The nodal displacements of the central area of the paraboloid are less than 1mm, it certified that this tension cable system can satisfy the working precision.