展开桁架天线热致振动数值分析

Numerical Analysis of Thermally Induced Vibration for Deployable Truss Antenna

对一展开桁架抛物面天线,利用有限元法,建立瞬态热平衡方程,针对空间天线和热致振动的特点,提出温度场在时间域上收敛于正确解和稳态解的收敛准则;利用节点温度,模拟热动力荷载,对天线典型节点热致振动位移和天线形面精度进行了数值分析。研究表明,热致振动发生在热动力荷载急剧变化的初时阶段,合适的阻尼和结构形式可以消除热致振动;结构的热致振动响应,主要集中在结构固有振动特性中的各向主振动;由热致振动引起天线形面精度误差,呈现由急剧振动趋于静态的特性,但初始的振动幅值较大。

The thermal equation of a deployable truss parabolic antenna was derived by finite element method, the convergence criteria of real root and thermal steady state root about thermal equation were built according to the features of space deployable truss antenna. The thermal dynamic forces were simulated by model nodes temperature. Typical model node displacement and root mean square of antenna induced by thermal dynomic forces were discussed. The results show that thermally induced vibration occurs at the beginning of thermal dynamic forces great change and stops by damping and right structure type. The dynamic response is mainly structural basic frequency. At the same time, value of root mean square of antenna induced by thermal drastically changes at the beginning.