Geometry And Pretension Design Method And Software For Space Tensioned Hoop-Rib Antenna

Space hoop-rib antenna is a typical cable-net-truss antenna.In order to meet the needs of large diameter,small collapsed volume and high precision,the truss which support the cable-net is composed of a series of slender rods.The slender rods have high tensile and compressive stiffness but small bending stiffness.When the rods are bent,the supporting truss will deform,which leads to the low accuracy of cable-net geometry.In order to achieve the high accuracy of the cable-net geometry,based on the concept of"tensegrity",a geometry and pretension design method which is suitable for space tensioned hoop-rib antenna with rotating parabolic and shaped reflectors is proposed,taking cable tension and rod compression as constraints.（1）For parabolic reflector,the triangle and quadrilateral mesh topologies are designed respectively,and the cable-net-truss structure is decomposed into cable-net structure and reinforced cable-truss structure for geometry and pretension design.First of all,the geometry and pretension design optimization model of the cable-net structure is established and solved with the goal of uniform prestress.Then,assuming that the truss rods are subjected to axial compression only,the boundary forces of the cable-net structure are applied to the reinforced cable-truss structure and the pretension design of the cable-truss structure is carried out.Finally,the numerical simulations for the two types of hoop-rib antennas are carried out.The simulation results show that the shape accuracy of hoop-rib antenna can reach6.76×10^-5mm,which verifies the feasibility of the proposed method.（2）For shaped reflector,two shape forming schemes are proposed and the geometry and pretension of the shaped reflector antenna are designed.Firstly,an ideal shaped reflector with smooth surface is designed by POS software,the mesh optimization model is established with the theoretical error of the shaped reflector as constraint and the mesh topology of shaped mesh reflector is determined.Then,three-layer cable-net structure and double-layer cable-net-strut structure are proposed to solve the problem that there are convex points on the shaped surface.Then,combining the plane projection method and the least squares norm method,the pretensions of the two shaped reflector antennas are designed.Finally,the feasibility of the design method is verified by numerical simulation.（3）Based on the above research,the parametric software for geometric and pretension design of space hoop-rib antenna is developed.The software mainly includes three modules:input module,function module and display module.According to the basic antenna parameters input by users,the geometric configuration design,pretension design,finite element simulation results analysis and cloud image display of cable-net truss can be realized quickly.