空间结构热-动力学耦合系统稳定性的有限元分析

Stability analysis of coupled thermal-dynamic systems in space structures based on FEM

针对在轨航天器柔性附件的热-动力学耦合系统,提出了一种稳定性分析有限元方法。该系统的状态方程既包括考虑辐射换热且耦合了结构变形的非线性瞬态热传导方程,也包括与瞬态温度场相联系的结构动力学方程。由于结构变形对于受热条件的耦合影响以及辐射换热的存在,该系统具有高度非线性。借助于非线性振动理论,给出了系统热诱发振动的稳定性准则。针对不同的结构,可以计算出不同的运动稳定边界,该边界将参数空间分成了稳定区域和不稳定区域。对哈勃太空望远镜太阳帆板进行了稳定性分析,该方法所得数值解与文献结果一致。对更为复杂的卫星天线,用该方法给出其发生热颤振的参数条件,探讨了结构参数、加热条件对其热-动力学耦合系统稳定性的影响。

A finite element method （FEM） was developed to analyze the stability of coupled thermal-dynamic systems of flexible appendages in spacecrafts in-orbit. The system governing equations include dynamic equations related to the transient temperature field and nonlinear transient heat conduction equations, in which radiation heat transfer is considered and structural deformations are coupled. The coupling effect and the radiation create a highly nonlinear system. The criterion for thermally induced oscillatory stability of large space structures was established using nonlinear vibration theories. Different stability boundaries for different structures can be obtained, which divide the parametric space into stable and unstable regions. A stability analysis of the solar arrays on the Hubble Space Telescope agrees well with reference data. The effects of structural properties and heating conditions on the motion stability of a more complex antenna are also discussed based on the parameters related to thermal flutter obtained.