输电塔在大风覆冰下的可靠度分析

Reliability Analysis of Transmission Tower Under Wind and Ice Cover

以覆冰厚度和风速为随机变量,基于蒙特卡洛法模拟分析了不同条件下的输电塔可靠度。基于响应面法拟合了输电塔的一次和二次功能函数,利用功能函数得到可靠指标与相关系数的关系式。另外将基于Copula函数的尾部相关性概念引入到风速与覆冰厚度的相关性分析中,并与结构的可靠度分析相结合。结果表明:风速和覆冰厚度的增加都会降低输电塔的可靠性,并且风速是输电塔可靠性的敏感因素。考虑大风与覆冰的负相关性会提高输电塔的可靠性。在覆冰出现极大值的情况下风速出现极大值的概率可达到5%,需要在设计时引起注意。

Establish the ice thickness and wind speed as random variable and analysize the reliability of transmission tower under different conditions by Monte Carlo method. Fit the function of transmission tower based on response surface method. Use function to get the relationship between reliability index and correlation coefficient. The correlation between the wind speed and the thickness of ice cover is introduced based on the concept of the tail dependence of the Copula func- tion. It is combined with the reliability analysis of structure. The results show that the increase of wind speed and the ice thickness both can reduce the reliability of transmission tower. Wind speed is a sensitive factor for the reliability of trans- mission tower compared to the ice thickness . The reliability of the transmission tower can be improved considering the negative correlation between the wind and the ice cover. Under the condition of maximum ice cover, the probability of the maximum value of wind speed can reach 5 % which needs to pay attention in the design.