台风“梅花”作用下中国航海博物馆风场特性及风振响应实测分析

Field measurement on wind filed characteristics and wind-induced vibration response of China Maritime Museum during typhoon 'Muifa'

采用超声风速仪与加速度传感器,对台风"梅花"作用下中国航海博物馆周围风场及双曲面索网结构风振响应进行现场实测,对脉动风速的概率密度分布、湍流度、阵风因子、湍流积分尺度、风速功率谱等风场特性及加速度概率密度分布、反应谱、结构自振频率、阻尼比、振型等风振特性进行研究.结果表明:脉动风速的概率密度分布符合高斯分布;湍流度和阵风因子随平均风速的增大而减小;顺风向、横风向、竖向脉动风速影响下顺风向湍流积分尺度平均值的比值为12.1∶3.4∶1.0,湍流积分尺度与平均风速相关性较小,随湍流度的增大而减小;实测脉动风速谱与Von Karman谱较为吻合;风振具有较强的非高斯性,随振幅阈值的增长,阻尼比的变化可分为线性递增段和平稳段,利用谱分析法、随机减量法、随机子空间法等方法计算得到的自振频率较为一致.

The field measurement of the wind field around China Maritime Museum and the wind-induced vibration response of China Maritime Museum＇s hyperbolic cable net structure during the typhoon ‘Muifa＇was carried out by using ultrasonic anemometers and accelerometers. The wind field characteristics of typhoon ‘Muifa ＇,such as the probability density distribution of the fluctuating wind speed,the turbulence intensity,the gust factor,the turbulence integral scale and the wind speed power spectra,and the wind-induced vibration characteristics,such as the probability density distribution of the acceleration,the power spectra,the natural frequency,the damping ratio and the mode,were analyzed. The results showthat the probability density distribution of the fluctuating wind speed follows the Gaussian distribution. The turbulence intensity and the gust factor decrease with the increase of the mean wind speed. The ratio of the average longitudinal turbulence integral scale influenced by the longitudinal,lateral and vertical wind is 12. 1∶ 3. 4∶ 1. 0. The turbulence integral scale is weakly correlated with the mean wind speed and decreases with the increase of the turbulence intensity. The measured spectra of the fluctuating wind speed agree with the Von Karman spectrum. The wind-induced vibration has strong non-Gaussian characteristics. With the increase of the amplitude thresholds,the change of the damping ratio can be divided into the linear incremental stage and the stationary stage. The natural frequencies obtained by the spectral analysis method,the random decrement method,and the random subspace method are in good agreement.