一种冷热交变环境下太阳帆应力保持方法

针对冷热交变环境导致太阳帆内部应力剧烈变化的问题，基于形状记忆合金(SMA)弹簧提出了太阳帆的张拉方案和薄膜应力保持恒定的方法，该方法利用形状记忆合金在高低温下的刚度非线性特性，有效补偿薄膜和支撑杆之间的间隙变化，以使薄膜内部应力基本保持恒定。针对六边形构型太阳帆开展了数值仿真，首先建立了太阳帆的热分析模型和力学分析模型，获取了高低温工况下的温度场。然后通过热致变形分析得到薄膜与支撑杆在高低温工况下的间隙变化，据此确定形状记忆合金弹簧的参数。最后对太阳帆在高低温工况下的薄膜内部应力进行了验证。

A Stress Keeping Method of Solar Sails in Alternating Cold and Hot Environments

Alternating cold and hot environments would cause severe change of internal stress of the solar sail film. To solve this problem, based on the shape memory alloy (SMA) spring, the method of keeping the film stress constant is proposed. This method uses the nonlinear stiffness of the SMA at high and low temperatures to effectively compensate for the gap between the film and the boom, so as to keep the film stress constant. Firstly, the thermal analysis model and structural model of the solar sail are established, and the temperature field under high and low temperature conditions is obtained. Then, the gap change between the film and the boom at high and low temperature are obtained by thermal deformation analysis, and the parameters of SMA spring are determined. At last, the change of film stress under high and low temperature conditions is verified.