太阳帆航天器在绕地轨道中的热诱发振动

太阳帆航天器在绕地轨道中将会周期性地进出地球阴影，经历热环境的剧烈变化，在热辐射冲击作用下，太阳帆这种大柔性空间结构的热致响应值得研究。以方形有桅杆式太阳帆为研究对象，考虑热辐射等非线性因素，建立了太阳帆的热-结构耦合动力学模型，分析了太阳帆桅杆-薄膜结构热诱发振动的特点和影响因素。分析结果表明：太阳帆由地球阴影区进入光照区将会发生明显的热诱发振动；随着热流入射角的增大，太阳帆桅杆截面的摄动温度减小，热诱发振动减弱，频率不变；太阳帆桅杆刚度的增大有利于抑制结构热诱发振动的发生；帆膜预应力将会影响太阳帆的热诱发振动，随着桅杆轴力增大，热诱发振动的振幅增大，频率减小，当轴力增大至一定程度，太阳帆的热诱发振动将会发散。

Thermally-induced vibration of a solar sail in earth orbit

When solar sails are orbiting earth, the day-night transits will cause sudden change of thermal environment of solar sails. Thermally-induced structural response of solar sails due to this thermal shock is worth studying. Considering the nonlinear effect of heat radiation, thermal-structural coupling dynamic equations of a five-point suspension square solar sail are established and then the thermal-structural analyses are conducted.The characteristics and affected factors of thermally-induced vibration of the solar sail are analyzed. Numerical results show that the noticeable thermally-induced vibration happened to the five-point suspension square solar sail. The perturbation temperatures of boom cross-section and the thermally-induced vibration of the sail decreased, but the frequencies remain constant when the incident angle of heat flux increased. The increasing thickness of the boom cross-section will be beneficial to suppressing the thermally-induced vibration of the sail. The prestress of membranes of the sail could affect the thermally-induced vibration. As the axial load of the boom increases, the vibration amplified increases and the frequency decreases. The thermally-induced vibration may become unstable when the axial load of the boom increases to some extent.