In order to grasp the fatigue characteristics and reliability of aluminum strands of long span overhead transmission lines under the loads of gentle winds,a probability density evolution based calculation method for the aluminum fatigue reliability of long-span transmission lines is proposed.Firstly,a finite element model of the large span tower line system was established,and the vibration displacement history at the suspension point of the wire under the gentle wind excitation was studied.Then,a finite element solid model of the wire segment was constructed,and the fatigue stress history response of the aluminum strands inside and outside the large span wire under the displacement-history wind excitation was studied.Finally,the probability density evolution method was used to analyze the fatigue reliability of large span conductors,considering the distribution probability of wind speed and direction.The results were compared with those of the Miner's linear cumulative damage.The results show that the higher the breeze wind speed,the greater the vibration amplitude of the large span wire.Under the action of gentle winds,the stress of the outer aluminum strand of the large span conductor is greater than that of the inner aluminum strand,and the stress of the outer steel strand is also greater than that of the inner layer.The longer the service life of a large span wire,the lower the reliability of the inner and outer aluminum strands of the wire.Nevertheless,the reliability of the inner aluminum strands is stronger than that of the outer aluminum strands.The fatigue reliability of aluminum strands based on Miner's principle is relatively larger.It is recommended to consider the delamination characteristics in the fatigue design of large span transmission lines.
关键词
大跨越输电导线/概率密度演化/微风振动/铝股应力/疲劳可靠度
Key words
large span transmission lines/probability density evolution/breeze vibration/aluminum strand stress/fatigue reliability
维普
万方数据