Abstract:

The transmission tower-line structure under wind loads is a nonlinear coupled vibration system.Its members alternately undergo reversal stress due to the flutter component of the natural wind,which may result in the fatigue damage of the structure.In this paper,with a direct-current transmission line as a case,a method to analyze the wind-induced fatigue in time domain is proposed for the vibration of transmission tower-line system.Then,the random wind field is simulated by using the AR model,and the nonlinear time-history wind-induced vibration of the tower-line coupling system is analyzed.Moreover,an equation to calculate the fatigue cumulative damage affected by the distributions of wind direction and speed is established,and the dangerous members with potential fatigue cumulative damage are determined,followed by a detail stress analysis.Finally,the fatigue life of the members under wind loads is estimated based on the linear cumulative damage theory.It is found that the proposed time-domain analysis method can effectively estimate the residual life of the transmission tower in wind-induced vibration.

Key words: transmission tower-line coupling system, wind-induced fatigue, time-domain analysis, fatigue cumulative damage