考虑风速风向联合分布的双坡屋面风致疲劳研究

为研究风荷载作用下大跨度低矮建筑金属屋面板的疲劳损伤分布规律,以坡度为1/60的双坡屋面建筑为研究对象,基于1975～2019年间的风速风向数据,研究了双坡屋面板50年重现期的疲劳损伤累积值。采用Gumbel分布描述日极值风速分布,混合Von Mises分布描述风向分布,并用单参数Archimedean Copula函数描述二者的相关性,得到了风速风向的联合分布; 基于双坡屋面的测压风洞试验结果,考虑连续变化风速和离散风向角对疲劳寿命的影响,研究了金属屋面板的疲劳损伤累积值。结果表明:双坡屋面板疲劳损伤与主导风向、屋面位置等因素密切相关,位于主导风向处的迎风屋檐、边角等气流分离位置的疲劳损伤累积值远大于其他区域; 良态风环境下,该双坡屋面金属屋面板50年风致疲劳损伤累积值最大可达0.746,风荷载可引起迎风屋檐、边角位置金属屋面板的疲劳破坏; 对于金属屋面板而言,风致疲劳破坏是引发风揭事故的巨大隐患,应高度重视。

Study on Wind-induced Fatigue of Double-slope Roof Panels Considering Joint Distribution of Wind Speed and Direction

In order to study the fatigue damage distribution law of metal roofs used in long span and low buildings under wind loads, taking the double-slope roof building with a slope of 1/60 as the research object, based on the wind speed and direction data from 1975 to 2019, the fatigue damage cumulative value of the double-slope roof panel with a return period of 50 years was studied. The Gumbel distribution and the mixed Von Mises distribution were used to describe the daily extreme wind speed distribution and the wind direction distribution separately. The single-parameter Archimedean Copula function was used to describe the correlation between wind speed and wind direction, and the joint distribution of wind speed and direction was obtained. Based on the wind tunnel test results of the double-slope roof, the cumulative value of fatigue damage of the metal roof panel was studied considering the influence of continuously changing wind speed and discrete wind direction angle on the fatigue life. The results show that the fatigue damage of double-slope roof panels is closely related to factors such as the dominant wind direction and roof position. The cumulative fatigue damage in windward eaves, corners and other airflow separation locations at the dominant wind direction is much larger than that of other areas. The maximum cumulative value of 50 years wind-induced fatigue damage for the double-slope roof is 0.746 under, and wind load can cause fatigue failure of metal roof panels in windward eaves and corners. For metal roof panels, wind-induced fatigue damage is a huge hidden danger causing wind exposure accidents, which should be paid great attention to.