基于Hilbert-Huang变换的大跨桥梁非线性抖振响应时频分析

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。

Time-frequency analysis for nonlinear buffeting response of a long-span bridge based on HHT

Taking Xinjiang Saiwudiege’er Suspension Bridge as engineering background, this essay studies the characteristics of time-frequency of nonlinear buffeting response. The problem of distortion of Fourier Transform’s identification of frequency of the Bridge buffeting response is raised. The cause of the distortion is figured out from the perspective of signal analysis and the reason for non-stationary response is looked into from the perspective of structural dynamics. Hilbert-Huang Transform (HHT Transform), is introduced to analyze the marginal spectrum of the response. The time-frequency of empirical mode component in HHT Transform is analyzed, and the physical meaning of empirical mode component is discussed from the perspective of wind engineering. The analysis result shows that the nonlinear buffeting response of long-span bridge shall have a certain non-stationarity and HHT transform is obviously better than Fourier Transform in the identification of the frequency spectrum of buffeting response.