摘要
随着空间相机在政治、军事和国民经济生活中的作用日益显著，越来越多的国家加入研发的行列。目前，空间相机地面像元分辨力最高已达0.1m。在空间相机中，对地面像元分辨力起基础决定性作用的光学元件是主镜。主镜作为空间相机中质量最大的光学元件，其面形精度、位置精度要求十分严格。本文研究的主镜尺寸较大且外形呈长圆形，若要保证其高的面形精度、位置精度，难度更有所增加。因此在空间力热耦合的环境条件下，如何使得主镜组件的设计满足质量轻、主镜的面形精度、位置精度高以及静、动态刚度，静、动态强度合理的要求，成为空间相机设计的关键课题之一。
围绕主镜的设计约束条件，本文主要介绍了主镜材料的选择和几个典型结构参数的确定。即，通过对常用主镜材料的抗热变形品质因数和综合品质因数的定量分析，科学地完成了主镜的选材；应用有限元分析方法，借助于结构刚性品质因数的概念，研究了主镜轻量化孔的形状和主镜厚度对镜结构刚性品质的影响；通过对主镜组件的力热耦合分析，研究了主镜柔性支撑簧片厚度与高度对主镜面形的影响。
研究结果表明：对于本文的长圆形主镜，采用正六边形轻量化孔，镜体结构刚性品质最好，正方形次之，正三角形最差；主镜镜体厚度存在最佳值；主镜组件在1g重力、均匀温升4℃共同作用的工况下，主镜柔性支撑簧片厚度越小、高度越高，主镜综合面形误差(P-V值)越小，但同时主镜组件的刚体位移增大、固有频率下降，因此柔性支承结构参数的确定要综合考虑主镜的综合面形误差和主镜组件静态刚度、动态刚度、静态强度和动态强度等因素。
为了满足主镜的设计约束条件，主镜柔性支撑簧片厚度设计的较薄(1.3mm)，因此有必要对主镜组件的结构稳定性进行校核。计算表明，在发射过载条件下，主镜组件不会失稳。
主镜组件能否经受住地面运输和空间发射阶段动力环境的考验，是主镜组件设计校核的一个重要方面。主镜组件有限元模型动力学分析表明，本文设计的主镜组件足以抵抗动力学环境载荷的影响。
中国科学院硕士学位论文:基于有限元法的空间相机主镜设计
本文最终设计的主镜组件满足设计要求。
As space camera is showing its important effect in the domain of politics, military and national economy, more and more countries start theirs research and development about it. In the space camera, the most crucial optical component that affects the spatial resolution is the primary mirror, so the requirements of its surface figure and position precision are very strict. Because the strip mirror's dimension is large in this article, the design is more difficult. Naturally, the primary mirror design is becoming a key task of space camera development.
Around design requirements of the primary mirror, the article mainly introduces the process of the primary mirror material selection and some structure parameter's decision. That is, by the calculation of the anti-thermal deformation quality factor and synthetic quality factor of some typical primary mirror materials, the primary mirror material is selected scientifically and rationally. By the finite element method and the conception of structure rigidity quality factor, researching the relation between the light-weighted cell shape, the mirror thickness and mirror structural rigidity quality. By the force-thermal coupling analysis of the primary mirror assembly, the relations between the thickness, height of the flexible support reed and primary mirror synthesis surface figure error (p-v) have been researched.
The research result indicated: for the strip primary mirror discussed in this article, the hexagon light-weighted cell has the best structural rigidity quality, the square cell is a little worse, the triangle cell is the worst; there is an optimum on primary mirror thickness; on condition of 1g gravity load combining with 4 centigrade uniform temperature rising, the thinner and higher of the flexible support reed, the better of the primary mirror surface figure. The decision of the structural parameters of the flexible support reed must take static rigidity, dynamic rigidity, static strength and dynamic strength of primary mirror assembly into account.
For the flexible support reed is very thin (1.3mm), it's necessary to study the buckle of the primary mirror assembly. The calculation indicates that when space
camera is launched, the primary mirror assembly would work well.
It is also an important consideration in the structural design of the primary mirror assembly whether the primary mirror assembly can withstand the effect of dynamic load from the ground transport and the space launch process. The dynamic analysis indicates that the design of the primary mirror assembly is good.
The design of the primary mirror assembly meets requirements.
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