经纬仪主镜轻量化新方法  

New technology for lightweight large primary mirror of theodolite

作　　者：谭凡教[1] 乔彦峰[1] 李耀彬[1] 高慧斌[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《光学精密工程》2008年第1期22-28,共7页Optics and Precision Engineering

基　　金：国家863高技术计划资助项目

摘　　要：为了优化2m口径经纬仅主镜概念轻量化结构，根据柔性极小化原则，采用了有限元拓扑分析方法。分析得出，不同材料镜面的优化轻量化结构，其重点保留位置比较接近，最外圈半径为889．5mm，最内侧圈半径为235mm，中间几个保留半径为720～730mm和610～620mm；从轻量化率看，非圆形孔结构平均为70％，圆形孔结构为50％以上；比较微晶玻璃镜面两种轻量化的优化结果，固有频率均为300Hz左右，相对于实体镜，定位作用反力降低很多。分析SiC镜面各种轻量化结构的镜面变形和固有频率得出：圆形孔非均匀分布和封闭六边形结构的镜面位移为（0．42～0．45）×10mm，圆形孔均匀分布和开放式六边形结构为（0．58～0．59）×10mm；圆形孔均匀分布结构的频率为1200Hz，圆形孔非均匀分布为1680Hz，六边形结构为1620～1670Hz左右。分析结果表明，镜面重力载荷分布是非线性的，镜背轻量化结构分布也是非均匀的，这有利于控制镜面变形和固有频率，可供轻量化设计参考。In order to optimize conceptual lightweight structure for ture theodolite, the conceptual lightweight structure was optimize （FEA） topology according to minimum flexibility principle. From e primary mirror of a 2 m aperwith Finite Element Algorithm e computation result, major remain radial is close for different mirror materials, in which the outside radial is 889.5 mm, the inner of 235 mm, and the middle radial places are 720-730 mm and 620~630 mm. The mean lightweight rate of non-circular type is about 70%, and the circular is above 50%. From optimization data of Zerodur mirror, natural frequency comes to 300 Hz,and the location reaction force declines largely according to a traditional mirror. Comparing the deformation of SiC mirror surface with uniform lightweight structure, the displacements of non-uniform circular structure and closed hexagon structure are about （0.42-0.45） × 10^-5 mm, while the uniform circular and open hexagon are （0.58-0.59）× 10^-5 mm. The natural frequency of uniform distribution circular is 1 200 Hz, while the non-uniform one is 1 680 Hz, and the hexagon is 1 620-1 670 Hz. The results show that for the gravity load distribution on mirror surface is nonlinear, and the distribution of lightweight structure is uniform, which is advantageous to the control of mirror surface deformation and natural frequency, and the design of lightweight structure.

关 键 词：经纬仪 主镜 轻量化 有限元拓扑方法 变形 固有频率 非线性分布 

分 类 号：TH703[机械工程—仪器科学与技术] V556.5[机械工程—精密仪器及机械]