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研究分析了500m口径射电望远镜(Five-hundred-meter Aperture Spherical Telescope,简称FAST)反射面索网支承结构的疲劳性能。模拟FAST主动变位工作模式(长时巡天观测和随机独立观测),计算30年设计基准期内连续工作运行的次数需求,分析FAST索网支承结构变位工作的随机疲劳应力历程,并基于简单抽样技术,对全寿命疲劳应力历程进行简化,采用实时雨流计数法进行分解;基于S-N试验曲线和Smith等效疲劳寿命极限应力线图,采用Miner线性损伤累积准则分析各索的疲劳寿命。以所有单索疲劳寿命的最小值作为整体结构疲劳寿命,多次模拟计算,统计分析保证率为99.9%的结构疲劳寿命,并合理选取安全系数2.0考虑疲劳寿命变异性影响。分析结果表明,在设计基准期内,结构疲劳寿命满足安全要求,结构疲劳危险区域主要分布在索网中心区域。
The fatigue properties of 500-m telescope (Five-hundred-meter Aperture Spherical Telescope, FAST) reflective net support structure were analyzed. The FAST active displacement mode (long-time observation and random observation) was simulated to calculate the number of continuous operation during the 30-year design baseline period. The random fatigue stress history of the FAST cable-stayed structure was analyzed. Based on the simple Sampling technique was used to simplify the fatigue life history of the whole life cycle and to decompose it by real-time rain flow counting method. Based on the SN test curve and Smith’s equivalent fatigue life limit stress diagram, the fatigue life of each cable was analyzed by using Miner linear damage accumulation criterion. Taking the minimum fatigue life of all single cables as the fatigue life of the whole structure, the fatigue life of the structure with the guaranteed rate of 99.9% was statistically calculated and calculated repeatedly, and the safety factor of 2.0 was reasonably selected to consider the influence of the variation of fatigue life. The analysis results show that the fatigue life of the structure meets the safety requirements during the design reference period, and the structural fatigue danger areas are mainly distributed in the center area of the cable network.