Dynamic Instability Analysis Of Transmission Tower-Line System Subjected To Wind Load

As a kind of important life-line system,transmission tower-line system has some particular characteristics:with high-rise tower,flexibility and large-span,has intensively nonlinear;Due to the characters of the structure,the main design load is windload.According to the statistics,lost stability subjected to dynamic windload is one of the most usual destruct form in the construction of transmission tower.So,the research in this aspect is very meaningful.The stability of transmission tower-line is nonlinear dynamic stability.Uuder the stochastic fluctuating windload,the stability of the structure is more complex than static load and some simple dynamic load,because of the uncertain of the load.At the present time,the main achievement in this aspect focus on the simple structure with few freedoms under the simple load,few people involved the research related to the complex structure as transmission tower.In this paper,the author based on the nonlinear buckling analysis and the transient analysis package of the finite element program ANSYS, researched the dynamic stability of a transmission tower in Shenyang by the method-Incremental Dynamic analysis combining with Budiansky-Roth criteria and displacement equivalency criteria.The thesis is divided into such parts as follows:Firstly,responsed to the basic characteristics of wind and the transmission tower,the author simulated the stochastic fluctuating that can be used in the posterior analysis by the harmonic wave superimposing method.Secondly,the author established the finite model of transmission tower by APDL(Ansys Parameter Design Language),the transmission tower member is simulated by BEAM188 element,considering the nonlinear of material and geometry.And then,according to the result of modal,nonlinear buckling and the transient analysis,the author researched the static and dynamic stability of a transmission tower by the method-Incremental Dynamic analysis combining with Budiansky-Roth criteria and displacement equivalency criteria.Thirdly,the exact finite model,with three towers and two lines,of transmission tower-line system is established.The lines,which were determined by the theory of curve line element,are simulated by LINK10 element.Through the modal and the transient analysis against the model,the paper researched the impact of line to the transmission tower-line system,and researched the dynamic stability of transmission tower-line system.