大型空间结构的热-结构动力学分析

空间结构在辐射换热条件下的热诱发振动是导致空间结构失效的一种典型模式。弄清热诱发振动的机理是理解热诱发振动失效的基础。本文针对常见的空间薄壁杆件结构，提出了一种能够对复杂结构及加热条件进行比较准确的温度场和热诱发振动分析的有限元方法。首先利用一种Founer-有限元方法，同时考虑杆截面内平均温度和温差，求解了包含辐射非线性的瞬态热传导问题，并推荐了一种有效降低求解规模的减缩近似方法-Lanczos方法。在此基础上，用有限元法求解了杆件结构的热诱发振动问题，并就杆截面内平均温度和温差对结构振动的影响以及最大动静态响应的比值分别进行了讨论．合理地解释了一类常见的热诱发振动现象，本文的数值算例说明了这点。

Thermal-Dynamic Analysis of Large Scale Space Structures by FEM

Thermally induced vibration of space structures, which are subjected to incident solar heat flux and emitting thermal energy by radiation, is one of typical modes of structural failure. To make clear the mechanism of thermally induced vibrations is the base of understanding thermally induced vibrations failure. For the widely used thin-walled tube space structures, a method which can simulate the thermal field and dynamic response accurately for actual complex structures and heat conditions by FEM is presented. First by using a kind of Fourier-FEM technique, considering the average temperature and temperature differences of the tube's cross section simultaneously, the transient heat conduction problem involving heat transfer by radiation is solved. And a reduction method-Lanczos method, which can reduce solution scale efficiently, is recommended. Then the dynamic response of tube structures is simulated by FEM. The effects of the average temperature and temperature differences of the tube section on the dynamic response, the ratio of the maximum dynamic responses to the static one are discussed respectively. The behavior of thermally induced vibrations can be explained reasonably. Finally, some numerical examples are presented to indicate this point.