Kotani Masaki, Imai Tadashi, Katayama Haruyoshi, Yui Yukari, Tange Yoshio, Kaneda Hidehiro, Nakagawa Takao, Enya Keigo
Aerospace Research and Development Directorate, Japan Aerospace Exploration Agency, Mitaka-shi, Tokyo, Japan.
Appl Opt. 2013 Jul 10;52(20):4797-805. doi: 10.1364/AO.52.004797.
The Japan Aerospace Exploration Agency has studied a large-scale lightweight mirror constructed of reaction-bonded silicon carbide-based material as a key technology in future astronomical and earth observation missions. The authors selected silicon carbide as the promising candidate due to excellent characteristics of specific stiffness and thermal stability. One of the most important technical issues for large-scale ceramic components is the uniformity of the material's property, depending on part and processing. It might influence mirror accuracy due to uneven thermal deformation. The authors conducted systematic case studies for the conditions of CTE by finite element analysis to know the typical influence of material property nonuniformity on mirror accuracy and consequently derived a comprehensive empirical equation for the series of CTE's main factors. In addition, the authors computationally reproduced the mirror accuracy profile of a small prototype mirror shown in cryogenic testing and hereby verified wide-range practical computational evaluation technology of mirror accuracy.
日本宇宙航空研究开发机构已研究了一种由反应烧结碳化硅基材料制成的大型轻质镜子，将其作为未来天文和地球观测任务的一项关键技术。由于比刚度和热稳定性的优异特性，作者选择碳化硅作为有前景的候选材料。对于大型陶瓷部件而言，最重要的技术问题之一是材料性能的均匀性，这取决于部件和加工过程。由于热变形不均匀，这可能会影响镜子的精度。作者通过有限元分析对热膨胀系数（CTE）条件进行了系统的案例研究，以了解材料性能不均匀对镜子精度的典型影响，并由此推导出了一系列CTE主要因素的综合经验方程。此外，作者通过计算再现了低温测试中所示小型原型镜的镜面精度轮廓，从而验证了镜面精度的广泛实用计算评估技术。
