【摘要】 以新疆赛吾迭格尔悬索桥为工程背景,研究非线性抖振响应的时频特性。提出了Fourier变换识别桥梁抖振响应的频谱的失真问题,从信号分析的角度寻找失真的原因,从结构动力学角度探讨响应非平稳性的导因。为解决这个问题,引入Hilbert-Huang变换(HHT变换)分析响应的边际谱。并分析HHT变换中经验模态分量的时频,从风工程角度探讨经验模态分量的物理意义。分析结果表明,大跨桥梁的颤抖振响应具有一定的非平稳性,HHT变换识别抖振响应的频谱时比Fourier变换精度更高。更多还原

【Abstract】 Taking Xinjiang Saiwudiege’er Suspension Bridge as engineering background,its time-frequency characteristics of nonlinear buffeting response were studied.The distortion problem of the frequency spectrum obtained with Fourier transformation for the bridge buffeting response was presented.The cause of the distortion was searched using signal analysis and what led to the non-stationary response was explored with the knowledge of structural dynamics.Hilbert-Huang transformation (HHT) was introduced to analyze the marginal spectrum of the response.The time-frequency of the empirical mode components in HHT was analyzed,and the physical meaning of the empirical mode components was discussed from the point of view of wind engineering.The analysis results showed that the nonlinear buffeting response of a long-span bridge possesses a certain non-stationaritness and HHT is obviously better than Fourier transformation in the identification of the frequency spectrum of the buffeting response.更多还原