地面重力环境下可展开天线索网结构形态分析

Structural analysis for cable net of deployable antenna under influence of gravity

为了模拟在地面环境测试时重力对可展开天线索网结构形面精度的影响和索网在天线展开过程中的内力变化情况,本文引入悬链线单元对天线索网结构进行了重力作用下的形态分析和计算。文中首先使用平衡矩阵线性分析方法计算出了天线索网结构各索段在无重力作用下的预张力值和索段原长;然后在不改变索段原长的条件下以悬链线单元模拟了可展开天线的上、下弦索网,以两节点直杆单元模拟天线的纵向索网,计算得到了索网结构在地面重力环境下的形状和内力分布,并仿真模拟了天线索网在展开过程中的形态和内力变化情况。基于文中的数值算例对可展开天线索网结构在重力作用下的形面精度以及在展开过程中的形态变化进行了仿真计算和分析。算例计算结果表明,自重作用下的天线索网形态与无重力作用下的索网形态差别很小,但天线索网结构在重力作用下的展开过程中,其内部各个索单元的张力表现出了强烈的非线性变化特征。

In order to simulate the influence of gravity on shape precision and pretension distribution of deployable cable net of antenna in ground test, and for getting inner force changes of cable net during the deploying process of antenna, the catenary element is used to establish finite element method(FEM) model of the cable net. Firstly, the balance matrix analysis method is used to find out optimal pretension distribution and undeformation length of cable net without consideration the influence of gravity, and then the FEM model of antenna cable net with undeformation cable length under the influence of gravity is established by using catenary element to simulate upper and lower cable net, and two nodes bar element to simulate longitudinal cable net. By solving this FEM model, the new shape and inner force changes of cable net during deploying process of antenna could bedetermined. Finally, a detailed simulation and analysis for cable net morphology of antenna on conditions with gravity influence and its changes during deploying process are given in numerical example. Results of the example suggest that difference between cable net shape of antenna with gravity effects and without gravity effects is very small, and during deployment process of antenna cable net in gravity state, all its cable elements have extremely nonlinear morphology in changes.