A combined method of Wigner-Ville distribution with a theoretical model for acoustic emission source location in a dispersive media

This paper presents a new Acoustic Emission (AE) source location method in combination with a Wigner-Ville Distribution (WVD) and a theoretical velocity dispersion model in dispersive rock. This method does not require measuring the first arrival time of a signal, and is able to provide reliable and identical Time-of-Arrival-Differences (TOADs) regardless of the frequency components in the obtained signals. The basic idea behind this is that, if at least two dominant frequency components in the output signals can be determined from the WVD analysis of the test results, a full wave dispersion curve of the arriving signal is obtained in accordance with the theoretical wave model, where the time differences between dispersion curves are identical through the entire effective frequency range of the AE transducers. Biot’s model was applied as a velocity dispersion model, and the smoothed pseudo WVD was used to reduce the cross-term interference. It was found that the frequency-dependent arrival time traveling with the group velocity was easily determined with the help of the theoretical model, and the source location results based on the WVD algorithm and theoretical model agree better with the true locations than those from the Time-of-First-Arrival Differences (TOFADs).