FAST反射面索网变位策略优化及疲劳评估系统研究

Five-hundred-meter Aperture Spherical radio Telescope (FAST) is designed to be supported by cable-net structure, which should enable its surface to form a paraboloid from a spherical shape in real time through active control. However, such form-changing operation would lead to about 500MPa of fatigue stress amplitude for the cable-net structure. Such stress amplitude is more than twice as much of that defined by the relative standard, thus the cable-net structure is the most critical and expendable part of FAST reflector system. If fatigue failure occurs, perhaps it will make a great loss due to the large pre-stresses stored in the cable. Thus, the safety of the cable-net structure has become a great concern in FAST engineering. Consequently, the present application would make an effort to two aspects: 1) find a more appropriate form-changing mode to release the fatigue stress amplitude of cable-net structure, which would be in favor of extending FAST service life. 2) develop an efficient system to estimate the residual life of cable-net structure, which can provide a reference for safety evaluation of FAST and play an important role in its accident prevention and stable operation. If this application is successful, its research results would make directive significance to improve the level of operation and maintenance of FAST telescope, and could provide technical storage for the safety evaluation system. Besides that, the fatigue test data of the ultra-high fatigue performance cable, specially designed for FAST telescope, would play an effective role in their promotion and application in other industrial fields.

五百米口径球面射电望远镜（FAST）采用柔性索网作为主要支撑结构，其独特的变位观测方式导致索网将长期承受高达约500MPa的疲劳应力幅。该应力幅约为相关标准规定值两倍以上，如果钢索结构在使用过程中发生疲劳破坏，可能导致的危害极大，故索网安全问题应该被重点关注。为此，本课题主要开展以下工作：一、通过对变位策略的优化，降低索网变位过程的疲劳应力幅，减小变位工作对索网造成的损伤，提高设备的整体可靠性；二、深入研究钢索结构的疲劳损伤机理，发展有效的索网安全评估系统，对索网疲劳破坏作提前预警，保证设备安全运行。 本研究项目对望远镜的运行及维护有直接的指导意义，可为索网的调试及安全评估工作提供必要的输入条件。此外，本研究项目所涉及的实验数据及相关机理分析，将对高性能钢索结构（专门为FAST研制）在桥梁等其它领域的推广应用产生推动作用，可为相关标准的制定或提升提供数据支持。

五百米口径射电望远镜（FAST）采用柔性索网作为主要支承结构，变位观测过程中索网将长期承受高达500MPa的疲劳载荷，约为目前相关标准规范规定值的两倍。索网结构将是该望远镜系统的关键易损部件，故本文主要开展如下工作：一、根据望远镜的科学目标，估算未来30年望远镜的观测轨迹，评估望远镜运行观测对索网结构疲劳性能的要求；二、结合环氧涂层技术和改进挤压锚固技术研制高疲劳性能钢索结构，并通过实验验证该种钢索结构可以满足该望远镜对索网结构的技术要求；三、建立索网变位工作的准实时仿真系统，对索网安全进行疲劳性能评估。