巨型射电望远镜(FAST)反射面支承结构日照温度场效应分析  

Effect of non-uniform temperature field under sunshine on the structure supporting the reflector of a large radio telescope-FAST

作　　者：金晓飞[1] 范峰[1] 沈世钊[1] 

机构地区：[1]哈尔滨工业大学,黑龙江哈尔滨150090

出　　处：《土木工程学报》2008年第11期71-77,共7页China Civil Engineering Journal

基　　金：国家自然科学基金跨学科交叉重点项目(10433020);国家自然科学基金天文联合基金项目(10778615)

摘　　要：研究分析500m口径球冠状巨型射电望远镜(Five-hundred-meter Aperture Spherical Telescope,简称FAST)反射面支承结构的日照温度场效应。借助ANSYS热分析模块,建立FAST反射面结构和实测周边地形的整体参数化有限元模型,计算最不利气候之一即夏季晴天无云天气各时刻的空气对流换热、太阳辐射、周围环境的长波辐射换热以及阴影遮挡等各种边界条件,在较为合理的结构初始温度场下,进行连续多天的时程分析,直至结构的任一点温度收敛于24h前的结果,并据此结果计算反射面结构温度变形和温度应力,给出日照下反射面形状拟合精度随时间的变化规律、结构应力的变化范围和分布规律。结果表明在日照下结构的温度场较不均匀,局部温差最高达到了11℃,较大地影响了反射面形状精度,为将来结构的设计、施工、监测以及控制提供了参考信息。The effect of non-uniform temperature field under sunshine on the structure supporting the reflector of the FAST, Five-hundred-meter Aperture Spherical Telescope, is studied. Based on the thermal analysis module of ANSYS, an integral parametric finite element model is established for the structure supporting the FAST reflector and its measured landform, and the boundary conditions of periodic air temperature, solar radiation, long-wave radiation and shadow of the surrounding environment, etc., are computed each half hour in a cloudless day in summer as one of the worst-case weather conditions, then the transient temperature analysis under sunshine which sustains several days with a rational initial structure temperature field is terminated when the temperature everywhere is convergent to the results for the day before, subsequently the related temperature deformation and stresses are computed. Finally, the variation of the fitting accuracy of the reflector shape as well as the distribution and variation range of structure stress under sunshine are figured out. The results show that the temperature field under sunshine is quite non-uniform （the highest local temperature difference reaching 11℃）, which significantly influences the fitting accuracy of the reflector shape, and would supply valuable references for FAST.

关 键 词：FAST 日照温度场 时程分析 温度变形 温度应力 

分 类 号：TH751[机械工程—仪器科学与技术] TU311.41[机械工程—精密仪器及机械]