1m口径主反射镜支撑系统的优化设计

应用有限元法并借助有限元分析软件建立了主镜的三维实体有限元模型,对1m主镜的支撑系统进行了优化设计。分析比较了两种常用主镜侧支撑结构,优化确定了轴向支撑半径、侧支撑方式和侧支撑点位置。分析计算显示主镜处于不同俯仰角位置时的最大面形精度RMS值为5.3nm,满足设计指标要求,该有限元优化设计方法和过程不受主镜直径及厚度的影响,适用于平面、球面、非球面甚至异形面主镜的设计。结果表明了所设计的支撑系统方案的合理性与可行性。

Optimal design of support system for a 1 m diameter primary mirror

The support system of a one-meter primary mirror was optimally designed by the finite element method. For the analysis, the 3D solid finite element model was estabilished by the finite element software. Two kinds of lateral support structures were compared, then the axial support-ring radius, lateral support form and the lateral support position were determined after the optimum design. The mirror deformations with different pitching angles were calculated, and the maximum Root-mean-square(RMS) value of the surface deformation is 5.3 nm. Obtained results satisfy the design requirement and show that the support system is reasonable and feasible. This optimal method of finite element and calculated process are independence on the diameter and thickness of the primary mirror, and are also useful for the designs of primary mirrors in the planar form, spherical form and allotype form.