基于断线张力的输电塔架整体稳定性研究

Research on Overall Stability of Transmission Tower under Broken Wire Load

断线张力是输电线路倒塔的最重要因素之一.利用非线性有限元理论,针对500kV猫头式输电塔,研究了10种加载模式下的极限承载力和破坏形式.计算结果表明,不同的加载模式下输电塔架的破坏形式可以分为三个类型:塔架整体弯曲失稳破坏、从加载点开始杆件逐步进入塑性导致的整体失稳破坏和第一段塔腿斜撑及辅材面外失稳造成的整体失稳破坏.在承受扭矩和较大偏心的加载模式下,塔架的整体扭转承载能力相对较弱;当扭转达到临界角度时,塔架必然屈曲,直至最终破坏.

Broken wire load is one of the most important factors to cause transmission tower collapse.Based on the nonlinear finite element theory,the ultimate carrying capacity and failure modes of 500kV cat-head transmission tower with ice load are studied in 10different loading modes.The results show that the tower failure modes in different loading modes can be divided into three types:overall bending instability,overall instability with plastic development beginning from the bars near load point and overall instability caused by out-plane buckling of ranking shores in first section of the tower. Under large torsional torque and eccentric loading mode,the overall torsional load capacity of the tower becomes relatively weak.When the twist reaches the critical angle,the tower will inevitably bend and cause eventual destruction.