FAST索网大天顶角工况下结构响应分析  

Structural response of the FAST cable-net at large zenith angles

作　　者：张宁远[1,2] 罗斌[1,2] 沈宇洲 姜鹏[3,4] 李辉[3,4] 李庆伟[3,4] ZHANG Ningyuan;LUO Bin;SHEN Yuzhou;JIANG Peng;LI Hui;LI Qingwei(Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education,Southeast University,Nanjing 211189,China;National Prestress Engineering Research Center,Southeast University,Nanjing 211189,China;National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;Key Laboratory of FAST,Chinese Academy of Sciences,Beijing 100101,China)

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,南京211189 [2]东南大学国家预应力工程技术研究中心,南京211189 [3]中国科学院国家天文台,北京100101 [4]中国科学院FAST重点实验室,北京100101

出　　处：《清华大学学报（自然科学版）》2022年第11期1809-1815,1822,共8页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金面上项目(11973006);国家自然科学基金资助项目(11673039)。

摘　　要：500m口径球面射电望远镜(five-hundred-meter aperture spherical radio telescope,FAST)反射面支承于索网结构上,通过促动器控制下拉索实现反射面的主动变位。在大天顶角工况和换源过程中,索网强度和疲劳尚待进一步研究。该文根据监测数据修正索网分析模型,利用修正后的模型对大天顶角主动变位工况的结构响应进行分析;提出修正焦比和安全变位策略,以改善大天顶角工况下的结构超限情况;研究了大小天顶角转换的换源过程中结构响应变化规律。结果表明:大天顶角工况下总过渡区始终为最外圈150根下拉索,该范围不受温度影响;调整后的新焦比可明显减少面索超限工况数;安全变位策略可在保证面型精度的前提下,确保面索索力和应力幅不超限;大天顶角至大天顶角的换源工况为换源最不利工况。The five-hundred-meter aperture spherical radio telescope(FAST)is supported by a cable-net structure with active shape changing of the reflecting surface realized by hydraulic actuators controlling the cables.The strength and fatigue life of the cable-net have not been verified for large zenith angles and large source changes.The cable-net analysis model was modified based on current monitoring data to analyze the structural response of the cable-net for shape-changing operations at large zenith angles.A modified focal ratio and shape-changing strategy were developed to reduce excess stresses and stress amplitude at large zenith angles.The structural response analysis were carried out during the source-changing process when changing the zenith angle.The results show that the total transition zone always involves the 150cables in the outermost ring for large zenith angles,with this result not being affected by temperature.The use of modified focal ratios can significantly reduce the number of excess stress conditions.A safe shape-changing strategy ensures that the surface cable stresses and stress amplitudes remain within the stress limits while still maintaining the surface accuracy.Source changing from one large zenith to another large zenith angle is the most unfavorable condition.

关 键 词：FAST 索网结构 大天顶角 安全变位 换源过程 有限元 

分 类 号：TH751[机械工程—仪器科学与技术]