Crack detection, Hilbert–Huang transform, Wavelet analysis Abstract. This paper illustrates the feasibility of the Hilbert–Huang transform (HHT) as a signal processing tool for detecting structural cracks. HHT is a promising method to extract the properties of nonlinear signals. However the HHT has some shortcomings, for example some undesirable pseudo-IMFs and multi-component IMF. The crack detection method based on the wavelet analysis and HHT is proposed to analyze response signals: the wavelet analysis is used to decompose the signal into a set of narrow band signals prior to the HHT. Then, a screening process is conducted to remove unrelated IMFs. By comparing the IMFs’ instantaneous amplitudes, the existence of structural crack is detected. Finally, the experiment results of the cantilever beams prove the reliability of this method.