异形曲面屋盖结构脉动风压的非高斯特性及峰值因子的研究

Study on Non-Gaussian Characteristics and Peak Factors of Fluctuating Wind Pressure on a Special-Shaped Curved Roof Structure

在大气边界层风洞中对异形曲面屋盖进行测压试验,获得了作用于屋盖表面脉动风荷载时间序列,分析了屋盖脉动风压的偏度、峰度、概率密度、相关系数和相干性,并采用峰值因子法和Sadek-Simiu法评价了非高斯区域典型测点的峰值因子。结果表明:屋盖前缘及弧度变化较大处的脉动风压偏度、峰度和概率密度函数与高斯分布存在明显的差异,具有显著的非高斯特性;测点相关系数随测点间距的增大而减小,边缘测点相关性高于中间测点;测点脉动风压相干性在低频段随频率的增大而减小,高频段维持在0.2左右,相干性随测点间距的增大而减小;Sadek-Simiu法求得的峰值因子能更安全地估计非高斯区域测点的极值风压。

A pressure measurement test was conducted on a special-shaped curved roof in the atmospheric boundary layer wind tunnel,and the time series of fluctuating wind loads on the roof surface was obtained.The skewness,kurtosis,probability density,correlation coefficient and coherence of fluctuating wind pressure on the roof were analyzed.The peak factor method and Sadek-Simiu method were used to evaluate the peak factors of typical measurement points in the non-Gaussian regions.The results indicated that the skewness,kurtosis and probability density function of the fluctuating wind pressure at the leading edge of the roof and the place where the radian changed greatly was significantly different from the Gaussian distribution,and had obvious non-Gaussian characteristics.The correlation coefficients of measurement points decreased with the increase of distance between measurement points,and the correlation coefficients of measurement points at edges were higher than that of measurment points in the middle.The coherence of fluctuating wind pressure decreased with the increase of frequencies in the low frequency band,and the coherence maintained about 0.2 in the high frequency band.The coherence decreased with the increase of distance between measurement points.The peak factors obtained by Sadek-Simiu method could more safely estimate the extreme wind pressure of measurement points in the non-Gaussian region.