A comparison of wavelet transform and Hilbert-Huang transform for modal parameter extraction of structure

This paper presents the use of time-frequency decomposition based on two novel methods termed wavelet transform (WT) and Hilbert-Huang transform (HHT) for modal parameter extraction of structure. The impacts of modal separation, end effects, and noise levels on the time-frequency resolutions of these two approaches are investigated and compared by using numerical simulations. To verify their effectiveness on the real structure, an experimental study is implemented on a bridge model subjected to impact load and ambient vehicle loadings. The parameter identification results demonstrate that both the WT and HHT are effective as the time-frequency resolutions are given sufficient concerns, whereas from the viewpoints of parameter selection and quantitative analysis, in some sense, the WT method seems to be more theoretical and efficient than the HHT.