Wavelet analysis and Hilbert-Huang transform of blasting vibration signal

By means of wavelet transform (WT) and Hilbert-Huang Transform (HHT), a practical blasting vibration signal was analyzed and the presented results show that both WT and HHT are efficient ways for analyzing and processing non-stationary signals, and can draw main characteristic information from signals as well as carry out wave filtration and noise elimination. In HHT the intrinsic mode function (IMF) obtained with empirical mode decomposition (EMD) can reflect the intrinsic physical characteristics of original data and it has no need of using base functions, while in WT selecting mother wavelet is a difficulty problem. Hilbert energy spectrum can clearly express the energy distribution with time and frequency in detail, and most energy are concentrated in a definitive range of time and frequency, but that of wavelet spectrum lines are distributed in a wider frequency range. Besides, the resolving power of time and frequency is restricted from Heisenberg principle in wavelet analysis, while in HHT time resolving power is precise and steady, and frequency resolving is adaptive according to signal intrinsic characteristics. Conclusion can be made that the HHT method is more adaptive than WT analysis in analyzing non-stationary signals and has a wide application on wave in rock transmitting, attenuation law, restructure dynamic response characteristics and blasting vibration damage.