为了考核拼焊式SiC反射镜在一定温度波动范围内的面形稳定性,利用有限元方法模拟了在温度水平试验条件5℃温差下反射镜的热变形情况。利用曲面方程拟合方法处理镜面变形数据,计算出变形后的镜面面型误差RMS值为1.841nm,满足航天用反射镜对面形指标的要求,考核了该反射镜在一定环境温度范围内的面形稳定性。将模拟结果与相同条件下的环境试验结果相比较,二者误差为3%,具有较好的一致性。验证了该有限元模型以及性能参数的合理性,可为今后更大口径的拼焊式SiC反射镜的研制提供数值模拟基础和材料参数依据。

In order to evaluate the stability of the surface optics figure on the brazed SiC mirror within a certain temperature range,the finite element method is applied to simulate the thermal deformation of the mirror in the temperature difference test within 5℃ temperature range. The distorted mirror surface is fitted with the equation of curved surface fitting method. The calculated RMS of aberration is 1.841nm. It can meet the requirements of the reflecting mirror surface shape index for space,accordingly the surface optics figure stability of the brazed SiC mirror in a certain temperature range is qualified. After comparing the simulation results with the test results which is under the same test condition,the error of them is 3%,which can verify the rationality of the finite element model and material property. It can provide the simulation template and material parameters reference for the study of larger aperture brazed SiC mirror.