Dynamic Analysis Of Progressive Collapse Of UHV Transmission Tower Line System Based On Alternate Path Method

In recent years,China's rapid economic development,the overall demand for electricity continues to grow,UHV transmission lines are gradually being widely used.As a lifeline project,UHV transmission line is a project to maintain the urban survival function system and have a significant impact on the national economy and the people's livelihood,and if a Progressive Collapse accident occurs,it will cause severe blow to the national economy.This article uses ANSYS finite element software of implicit nonlinear analysis method to establish the linear model and the single tower contains 6 base line tower tower line system model of UHV transmission tower and tower line system are analyzed using the progressive collapse process of dismantling component method.The main contents are as follows:(1)UHV selection in practical engineering strain section of line tower as the research object,based on the single tower finite element model,including the establishment of model of transmission tower,selection of material constitutive model;Then the single line tower modal analysis,to determine the basic natural vibration period and mode.(2)With the aid of the demolition member method,the key components are selected to carry out the numerical analysis of the progressive collapse of the single tower,and the failure time of the component and the failure criterion of the transmission tower are determined.The transient unloading method with equivalent initial load considering initial state is used to simulate the initial state of the whole structure and the subsequent sudden failure of the component in the course of a failure.Effects of single UHV line tower in the process of progressive collapse in rod internal force redistribution process,dynamic effect and main failure mode,determine the different parts of the material failure on the dynamic displacement structure at the top of the range of amplification factor.(3)based on a single UHV line tower finite element analysis model,considering the guide(ground)line form finding,guide(ground)influence line and tower coupling and insulator,a transmission tower line system finite element analysis model.On this basis,we observe the collapse process and the main failure mode of transmission tower line system,and the collapse process of pilot line(to)the influence of unbalanced tension on the subsequent transmission tower are analyzed.(4)the most unfavorable disconnection condition and the deformation of the material straight bar internal force variation of different,to find out the tower line disconnection condition may be the initial damage and the geometrical position of the weak members,provide a reference for the design of transmission line.