| The transmission tower structure is a high-order statically determinate space structure that is widely used in power transmission systems.With the constant development of our country’s economy and modernization,the transmission system has become the lifeline of the country’s economic development,and its safety and reliability are increasingly valued.The safety of the transmission tower structure is directly related to the safety of the entire transmission system.Therefore,it is of great engineering value and practical significance to study the ultimate bearing capacity of the transmission tower structure.The transmission tower structure often collapses under thunderstorm climate conditions.Among them,downdrafts cause the largest number of transmission tower collapses,which brings huge economic losses,In China,the strong winds caused by downburst did not be studied too much.the design specifications of the transmission tower used in the atmospheric boundary layer wind,and the boundary wind is essentially different from the downburst storm.Therefore,it is very necessary to study the impact of downburst on transmission tower-line wind resistance design.Based on existing research data,this paper conducts a comprehensive research and analysis on the theoretical analysis method and the mechanical performance of the transmission tower structure.In the analysis process,the geometric nonlinearity and the material nonlinearity are taken into account respectively for the transmission tower structure.the nonlinear buckling analysis considering the dual nonlinearity of the transmission tower structure.In this paper,ANSYS finite element analysis software is used to establish a transmission tower-line spatial structure system.The downburst storm load is calculated according to the formula and loaded on the transmission tower structure to analyze its elasto-plastic properties,and determine its internal force,displacement and deformation.The analysis and study of the tower line system under the action of blitz flow at different wind angles,and the ultimate bearing capacity of the transmission tower-line structure under various working conditions was obtained.It was found that the carrying capacity of the 0°working condition was the highest;Under the 45°working conditions,the transmission tower has the lowest bearing capacity,and the weak part of the tower is located at the tower leg,which proves that in reality many transmission towers collapse due to the destruction of the tower leg.The effects of tower line system model,wind direction angle,wind profile model and maximum wind speed parameter Zmaxax on the carrying capacity of the transmission tower were discussed.Among them,the study found that the limit wind speed of the transmission tower under the impact of downburst will increase with the increase of the maximum wind speed height Zmax,and the displacement of the tower at the same height is very similar when the transmission tower is under the limit load. |
