导线覆冰脱落的数值模拟和参数分析

导线覆冰脱落产生的纵向不平衡张力会严重威胁到输电线路的安全。在塔线体系模型基础上利用冰单元的生死模拟导线覆脱冰，通过与以往的模型试验比较验证该模拟方法的适用性，进行建模参数的敏感性分析以确定合适的计算模型，最后进行导线脱冰的参数分析。计算结果表明，脱冰前输电塔的基底剪力和基底弯矩为零，脱冰后两者大幅增加，且越靠近脱冰档数据越大。当档距越大、覆冰越多、脱冰位置越靠中间和脱冰比例越大时，脱冰响应越显著；当导线的初始张力越大时，脱冰响应越小。

Numerical simulation and parametric analysis of ice-shedding on conductors

The longitudinal unbalanced forces induced by ice-shedding on conductors significantly threaten the safety of transmission lines.Based on the finite element model of a tower-line system,the methodology using the life and death of ice elements was employed to simulate the ice accretion and ice-shedding on conductors.This methodology was validated by comparing the simulation results with those obtained from the model-scale tests done by previous researchers.The sensitivity analysis of model parameters was performed to determine the appropriate computing model.With this model,the parametric analysis of ice shedding on conductors was conducted.Results showed that the base shears and base moments of transmission towers are essentially zero before ice-shedding and increase significantly after ice-shedding;furthermore,the base shear and base moment of a transmission tower become larger when the tower is closer to the ice-shedding span;the responses induced by ice-shedding decrease when the initial stress on conductors is larger and increase when the length of span,the amount of accreted ice and the ratio of ice-shedding are larger.