Structural Shape-State Optimization Design Of Cable-net Antenna With Rim Trusses

With the flourishing development of satellite communications,large cable-net antenna have become a form of space antenna that countries are competing to develop.Shape-state is a key technology in the design of cable-net antenna.In this thesis,the key problems of the initial topology,Structural Shape-State and thermal deformation of the cable-net antenna are deeply studied.The specific content is as follows:(1)For the initial topology design problem of cable reflector,focusing on the mesh reflector of the offset paraboloid antenna,the method of cutting the elliptical mesh reflector and the circular mesh reflector are described,and a method for dividing the boundary of the mesh reflector is presented.Secondly,the generation process of the initial topology of quasi geodesic cable reflector is given and the initial topology of cable reflector is got.Considering that the cable reflector topology is directly related to the antenna performance,the cable reflector topology m?n is designed.The relationship between the number of radial main cables m,the number of circumferential cables n and the uniformity of mesh tension,and the surface precision are analyzed,to get the appropriate cable reflector topology configuration.(2)For the problem of degradation of antenna performance due to the deterioration of mesh tension uniformity and surface precision caused by the deformation of the antenna rim trusses,a shape-state design method considering the elastic deformation of rim trusses is proposed.The design process of this method is divided into two steps: First step,with given uniform cable tension distribution,the numerical form-finding for cable net is performed.Second step,based on the given tension distribution of the cable net,combined with the force density form-finding algorithm and a nonlinear finite element method,the overall formfinding design of the cable net-rim trusses composite structure is carried out.This method is based on the whole antenna model,to calculate the structural deformation through the finite element method.Based on the deformed cable net structure and the given tension distribution,the form-finding is again performed.By iterative design,the cable net-rim trusses is obtained.This method is used to design the shape-state of the offset paraboloid antenna and the rotating paraboloid antenna respectively.The results show that this method can effectively reduce the influence of the rim trusses deformation on the performance of the mesh antenna,and improve the uniformity of mesh tension and the surface precision.(3)For the thermal deformation of the antenna caused by space temperature changes,the cable-net antenna is taken as the research object,and the antenna thermal deformation analysis process was described.Taking into account the conditions of-150°C and 110°C,based on the finite element method,the antenna thermal analysis model was established and cable-net antenna thermal deformation under temperature conditions is calculated.The effect of temperature changes on the tension uniformity and surface precision of cable-net antenna is analyzed.