腐蚀镀锌输电塔时变承载能力研究

Research on Time-varying Bearing Capacity of Corroded Galvanized Transmission Tower

摘要:

为了研究材料腐蚀作用下输电塔的安全性，通过数值模拟方法结合实验数据建立了输电塔镀锌钢材腐蚀后承载力退化模型。腐蚀效应通过在模型中引入人工腐蚀试验得到的材料力学参数和本构模型实现。在精细化有限元建模基础上对结构各关键点施加风荷载，以逐级加载方法计算不同腐蚀程度的模型关键点和塔腿的最大响应确定结构极限承载力。结果表明，由于腐蚀导致结构质量、刚度下降，输电塔基频随着腐蚀时间的增加不断降低，在镀锌钢材腐蚀周期为1200 h和4200 h时，输电塔承载力分别退化4.2%和5.3%。

Abstract:

In order to study the safety of transmission towers under material corrosion, a bearing capacity degradation model of galvanized steel for transmission towers after corrosion is established through numerical simulation methods combined with experimental data. The corrosion effect is achieved by introducing material mechanical parameters and constitutive models obtained from artificial corrosion tests into the model. On the basis of refined finite element modeling, wind loads are applied to each key point of the structure, and the maximum response of model key points and tower legs with different degrees of corrosion is calculated using a step-by-step loading method to determine the ultimate bearing capacity of the structure. The results show that due to corrosion, the quality and stiffness of the structure decrease, and the fundamental frequency of the structure continuously decreases with the increase of corrosion time. When the steel corrosion cycle is 1200 h and 4200 h, the bearing capacity of transmission towers deteriorates by 4.2% and 5.3%, respectively.