强风下输电塔-线体系连续性失效反演研究OA

Power transmission line is a typical wind-sensitive structure,which is widely distributed and very susceptible to strong winds,which results in damage or even collapse accidents,causing serious economic losses.Based on an actual collapse case of a transmission tower caused by strong wind,this paper firstly establishes a finite element model of the transmission tower-line system and simulates the wind load time histories for different wind speeds and wind attack angles with consideration of the randomness and the spatial coherence.Based on the nonlinear dynamic analysis method,the wind-induced response analyses of the transmission tower-line system under strong winds are carried out in terms of displacement and inter-segment displacement ratio(ISDR),as well as the stress responses of key steel members.The progressive failure process of the transmission tower-line system is subsequently numerically captured.The results show that,due to the tower-line coupling effect,the influence of wind speed randomness decreases gradually with the increase of the wind attack angle.The wind vibration responses of Segments 2 and 3 are relatively larger when the wind speed is 28 m·s-1 and the wind attack angle is 0°,indicating that these two segments are the weak positions of the tower.In addition,the failure mode of the tower obtained from the numerical simulation is basically the same as that of the actual tower.The buckling of some members leads to stress redistribution in the local area,and more failed members trigger the progressive collapse of the transmission towers.This study is intended to provide an available guide for the safe operation of transmission lines under strong winds.