长条形空间反射镜组件轻量化结构设计

针对某700 mm×249 mm长条形空间反射镜组件结构设计要求，对反射镜及其支撑结构进行了详细的光机结构设计。首先，从反射镜材料选择、径厚比、支撑方案及轻量化形式等角度出发，对反射镜进行结构设计。通过理论计算得到长条形反射镜的支撑点数。对支撑点位进行了优化，并探索了支撑孔位对反射镜自重变形的影响规律。其次，为满足反射镜组件的力、热环境适应性要求，设计了一种新型柔性支撑结构，并给出了柔性铰链薄弱环节对反射镜面形精度的影响；对支撑结构安装位置深度进行优化，给出反射镜面形精度关于支撑结构安装位置的变化曲线。然后，对反射镜组件进行了有限元分析，自重和5 ℃温升载荷工况下，反射镜面形精度峰谷（Peak Valley，PV）值和均方根（Root Mean Square，RMS）值最大分别达到58.2 nm和12.3 nm；反射镜组件一阶固有频率为259 Hz，低频正弦扫描振动条件下柔性支撑最大应力响应为138 MPa。最后，进行了动力学试验测试。测试结果表明，反射镜组件一阶固有频率为255 Hz，有限元分析误差为1.7%。分析和试验结果表明，反射镜组件结构设计合理，满足设计指标要求。

Lightweight structural design of rectangular space mirror assembly

According to the structural design requirements of a 700 mm×249 mm rectangular space mirror assembly, the mirror and its support structure were designed in detail. First of all, from the perspectives of material selection, diameter-to-thickness ratio, support scheme and lightweight form, the structure design of the mirror was carried out. The number of support points of the rectangular mirror was obtained by theoretical calculation. The support points were optimized, and the influence of the support holes on the deformation of the mirror's weight was explored. Secondly, in order to meet the requirements of the force and thermal environment adaptability of the mirror assembly, a new type of flexible support structure was designed, and the influence of the weak link of the flexible hinge on the surface accuracy of the reflector was proposed; the position of the support structure was optimized, and the change rule of the reflector shape accuracy with respect to the position of the support structure was proposed. Then the finite element analysis of the mirror assembly was carried out. Under the load conditions of self-weight and 5 ℃ temperature rise, the maximum Peak Value (PV) and Root Mean Square (RMS) of the mirror surface reach 58.2 nm and 12.3 nm; the first-order natural frequency of the mirror assembly is 259 Hz, and the maximum stress response of the flexible support under the condition of low-frequency sinusoidal sweeping vibration is 138 MPa. Finally, a kinetic test was carried out. The test results show that the first-order natural frequency of the mirror assembly is 255 Hz, and the finite element analysis error is 1.7%. Analysis and test results show that the design of the mirror assembly is reasonable and meets the design index requirements.