【作者】 王亮；

【导师】 瞿伟廉；

【作者基本信息】 武汉理工大学 ， 结构工程， 2011， 硕士

【摘要】 近年来,随着国民经济的进步,电力事业突飞猛进,作为电力输送的动脉,输电线塔结构也得到飞速发展。表现在输电塔越来越高,输电线跨度越来越大,随着输电塔高度增加和跨度增大,输电塔承受的挂线荷载和风荷载越来越大,输电塔朝着高柔的方向发展。日前输电塔设计中风荷载是按照静力荷载进行计算的,导线与输电塔结构通常是分开设计的,一般前者有电气专业的工程师分析,然后把导线荷载提供给结构工程师,当作外力加在输电塔上,通常仅考虑导线静力荷载的作用而忽略了导线与输电塔之间的藕合作用进行计算,这种方法是不太合理的,本文中采用输电塔线结合的模型对输电塔进行了分析。输电塔在恶劣的天气条件下倒塔事故时有发生,而在这样的恶劣条件下输电塔倒塔破坏通常伴随着雷暴大风天气,其中下击暴流引起的输电塔倒塔破坏事故较多,本文研究了在下击暴流作用下输电塔动力倒塔仿真分析。本文采用杆系结构模拟杆件,采用带有预应力的四节点模拟输电线,采用带预应力的杆单元模拟绝缘子,并用简化双线性恢复力模型模拟输电塔杆件的材料非线性,建立输电塔有限元模型。对杆件受弯压作用的失稳破坏特性进行了研究,用ansys程序对杆件在受杆端弯矩和轴向受压作用下轴向刚度的退化规律进行了计算,得到了动力计算可用的弯压失稳破坏准则。文中分析了下击暴流的一般特征,并采把下击暴流分解成一个时变平均成分和一个服从标准正态分布的幅值调幅函数部分,模拟了下击暴流的风荷载时程样本。并将这个下击暴流荷载作为外荷载施加到建立的输电塔模型上,考虑输电塔的受压失稳破坏准则,对输电塔进行弹塑性动力分析。对输电塔的分析可知道,输电塔破坏发生在塔身中下部,破坏形态为杆件受压失稳破坏,引起输电塔的最终倒塔。这与国内外输电塔真型试验的到的结果类似,并且与一些学者研究的输电塔在风力作用下是由于杆件承受受小于设计荷载内力而动力失稳破坏结论一致。更多还原

【Abstract】 In recent years, with the development of national economy, power industry develops very quickly.Transmission line play an important role in the operation of a reliable electical power system.transmission is becoming taller,and the transmission line span is getting bigger and bigger. Transmission tower withstanding more string load and the wind load. Transmission tower get more soft.The current design of transmission tower under wind loads is calculated according to the static load, Conductors and transmission towers and structures are often designed separately,the conductors designed by electric professional engineer,which provide wire load to structural engineer. Usually only consider the role of wire static load and ignored conductors and transmission tower with coupling, this method is not reasonable.Transmission tower collapses in adverse weather conditions now and than,which always accompanied thunderstorm.the downburst caused many accident in this weather condition.this paper studied the simulation of transmission collapse under downburst wind load.In this paper, the tower is modelled as an assembly of beam-column elements.four-node isoparametric curved element,and Prestressed pole unit simulation insulator,using bilinear Restoring Force Model to fomulate the Material nonlinear.Analyses the general characteristic of the downburst, And adopt the downburst decomposed into a time-varying average composition and the magnitude of a standard normal distribution function. Simulated downburst wind load time history samples,apply it as external load to the established transmission tower model. Consider the instability pressure transmission tower failure criteria, and the elastic-plastic dynamic analysis of power transmission tower.Analysis of transmission tower know that transmission towers destroyed in the lower part of the body of the Tower, compressive failure modes in the beam, causing transmission tower’s final tower. The result is similar to This full scale test of transmission tower.and Consistent with conclution that the menber failure at the smaller inner force by some Scholars.更多还原