大口径空间反射镜组件结构设计与分析

摘要

A diameter of 1.2 m space mirror and its supporting structure were designed. Firstly,Materials of the mirror and the support were reasonably selected. Taking account of the factor of technology,mechanical property,thermal property and lightweight,RB-SiC was chosen as the material of mirror and a new design with back semi-closed sector reinforced ribs lightweight structure was proposed,weight of mirror is 87.6 kg and lightweight ratio reaches to 79%.Secondly,mirror with the back three-point support scheme was determined,through the rational design of flexible sup-port structure parameters to ensure high stiffness and thermal dimensional stability. Finally,through using finite ele-ment analysis,the mirror subassembly was analyzed in detail. Analysis results indicate that the surface figure accuracy RMS can reach 7.8 nm and 9.4 nm under gravity and 4℃ uniform temperature rise respectively,and the first order natural frequency is 153 Hz,which can meet the design requirements.%设计了某1.2m口径的空间光学反射镜结构及其支撑结构系统。首先，合理选取了反射镜及其支撑结构的材料。从反射镜镜坯制作工艺、力学特性、热特性以及反射镜重量等因素考虑，最终选取基于反应烧结SiC材料的背部半开放式扇形轻量化孔的反射镜结构形式，反射镜设计重量为87.6 kg，轻量化率达到79％。其次，确定了在光轴水平状态下进行检测装调的方案，并进行其支撑结构的设计，采用3个双轴柔性铰链从背部对反射镜支撑，使大口径反射镜同时满足静态刚度、动态刚度、强度和热尺寸稳定性的要求。最后，对反射镜进行了组件级有限元分析。结果表明，反射镜在X向重力和4℃均匀温升作用下面形RMS分别为7.8 nm和9.4 nm，反射镜组件一阶固有频率为153 Hz，满足设计指标要求。