中国光学, 2016, 9 (6): 704, 网络出版: 2016-12-06
长条形空间反射镜无热化胶层的优化设计
Optimization design of athermal adhesive for rectangular space mirror
空间反射镜 环氧胶 无热化 有限元分析 静、动力学分析 space mirror epoxy adhesive athermalization finite element analysis static and dynamic analysis
摘要
为了实现尺寸为1 200 mm×484 mm的大长宽比长条形空间反射镜的无热装配, 减小反射镜面形精度受热应力的影响, 本文对环氧胶(GHJ-01(Z))胶层厚度对反射镜面形的影响及胶层在静、动力学载荷下的应力进行了研究。首先, 介绍了现有的几种基于胡克定律推导的无热粘结厚度方程及其假设条件, 并推导了带有锥度的背部盲孔反射镜无热粘结胶层厚度的方程, 得出无热粘结胶层厚度曲线; 然后, 建立了6种不同胶层厚度的反射镜组件模型并进行了分析与比较。通过分析, 在+5 ℃温升工况下, 反射镜胶层厚度为007 mm时具有最好的面形精度, 其RMS值00178λ, 其检测方向在自重作用下的面形精度RMS值为00173λ, 一阶频率为22017 Hz; 最后对胶层无热化设计后的反射镜组件进行了振动试验和粘结剂剪切强度试验, 分析与试验表明: 反射镜组件一阶频率为2164 Hz, 与有限元分析结果相对误差为171%; 满足动静态刚度要求; 同时, 在动力学载荷下该厚度胶层的应力均小于其固化后的抗剪强度, 安全裕度为246; 各项指标满足设计要求。
Abstract
In order to realize the athermal assembling of rectangular special mirror with large dimension of 1 200 mm×485 mm, and reduce the effect of hot stress on primary mirror′s surface figure precision, the effect of epoxy thickness on the surface figure accuracy of the mirror and the stress of epoxy under static and dynamic conditions are researched. First of all, several already existing athermal adhesive thickness equations obtained based on Hooke′s law are introduced. The athermal adhesive thickness equations of the primary mirror which has blind holes with taper in the back is developed, and the curve of athermal adhesive thickness is obtained. Then six modes of mirror with different adhesive thickness are made. The result of analysis shows that the mirror′s RMS are 00178λ(optical value) and 00173λ(gravity in detecting′s directions) under 5 ℃ uniform temperature rise when the epoxy thickness is 007 mm. Finally, vibration tests of mirror components and drawing test of epoxy are conducted. Analysis and experiment results indicate that its first order frequency is 2164 Hz and the error between them is 171%. The maximum stress of epoxy under dynamic conditions is smaller than the shear strength which is 302 MPa, obtained through drawing test of Epoxy, and the safety margin is 246. All indicators meet the design requirements.
李梦庆, 张雷, 邢利娜, 李宗轩. 长条形空间反射镜无热化胶层的优化设计[J]. 中国光学, 2016, 9(6): 704. LI Meng-qing, ZHANG Lei, XING Li-na, LI Zong-xuan. Optimization design of athermal adhesive for rectangular space mirror[J]. Chinese Optics, 2016, 9(6): 704.