【摘要】 基于Priestley演化谱理论,并结合小波变换原理,在理论上推导了非平稳随机过程演化谱估计的小波时域函数加权和法,从小波时域函数的角度建立了演化谱估计时域方法,弥补了传统演化谱估计方法需要小波频域函数这一不足。在此基础上,对实测台风"麦莎"全过程以及润扬大桥悬索桥在台风"麦莎"作用下的抖振响应进行了演化谱估计,分析了台风全过程及其风致响应的时频特性。研究结果表明:小波时域函数加权和法是一种估计非平稳随机过程演化谱的有效方法;台风"麦莎"全过程表现为强度强非平稳、频率弱非平稳,脉动风的脉动能量在整个台风过程中变化较大但主要频率成分变化较小;润扬大桥悬索桥主梁的风致抖振响应表现为强度非平稳、频率平稳,振动能量变化剧烈但频率成分基本不变。更多还原

【Abstract】 Based on the principle of wavelet transform and the theory of evolutionary spectrum developed by Priestley,the property that the evolutionary spectrum was equal to the summation weighted wavelet functions in time domain was deduced.A method,which could overcome the shortage of the traditional method that the closed-form expression of wavelet in frequency domain was required,was established to estimate the evolutionary spectrum of nonstationary stochastic processes.Based on the field measurement data on Runyang Suspension Bridge,the evolutionary spectra of typhoon Matsa and wind-induced vibration in main girder were estimated and the timefrequency characteristics were analyzed.The results show that the proposed method can calculate the evolutionary spectrum of nonstationary stochastic processes accurately and effectively.The fluctuating wind of typhoon Matsa is high and nonstationary in intensity aspect but weak and nonstationary in frequency aspect.The energy of the fluctuating wind varies dramatically with the typhoon passing but the frequency components change little.The wind-induced vibration of the main girder of Runyang Suspension Bridge is nonstationary in intensity aspect and stationary in frequency aspect.When typhoon passing,the vibration energy changes obviously but the frequency components are constant.更多还原