一种等张力空间索网结构找形方法

为设计出质量小、结构稳定的空间索网天线结构,给出了一种等张力索网结构找形的坐标迭代算法.将索网上的各节点看做只能在理想反射面上移动的点,并规定各段绳索中的张力是恒定的.各节点在合力的作用下运动,当作用在各节点上的合力逐渐减为零时,索网结构到达一种平衡状态,根据这一平衡状态可求出各段绳索的无应力长度.使用该算法对环形桁架索网天线计算模型进行了找形计算,并使用有限元法对找形得到的平衡状态进行验证,证明了该算法的正确性和可行性.同时将找形结果与极小范数法、等力密度这两种找形算法的结果进行了比较分析.分析结果表明,使用等张力找形算法得到的索网结构绳索张力的均匀性最好.文中所提的等张力找形算法可用于空间索网结构的找形.

Form-finding method of equal tension cable networks for space mesh antennas

To design large space deployable antennas with lightweight and stable cable-net structures, a form-finding method is presented to design equal tension cable networks. The nodes of the networks are regarded as the points that move on the ideal reflective surface. The nodes move on the ideal surfaces of the mesh antennas under the action of the resultant forces acting on the nodes, and the tensions in the cables remain equivalent. After a period of movement, the resultant forces acting on the nodes decrease to zero gradually, and the whole system is considered to be in equilibrium. The unstrained length of each cable can be determined according to the deformed length of the cable and the tension force in the cable. A numerical example of a hoop truss cable-net antenna was calculated, and the equal tension cable structure of the mesh antenna was obtained, whose equilibrium state was validated by the finite element method. The calculated results show that the method presented is accurate, valid and feasible. The calculated results are compared with the calculated results based on the minimum norm method and the equal force density method, which shows that the mechanical performance of the network that was obtained using the equal tension method is better than that by using the other two methods. The method can be used to design the cable-net structures of space mesh antennas.