The Research on Propagation Characteristics of Acoustic Emission Signals at the Coupling Interface of Components

Acoustic Emission technology is an effective nondestructive testing method, and it has been widely used in equipment health monitoring. So far, there are relatively few studies involving the propagation characteristics of signals in specific structural interfaces. In this paper, three experimental models of single plate, double plate (without couplant) and double plate (with couplant) are designed to analyze the influence of signal frequency and structural interfaces on the AE signal waveform and characteristic parameters in the propagation. First, the acquired signals are processed using wavelet transform and Rayleigh-Lamb equation analysis to extract the time-frequency characteristics, and then establish the attenuation coefficients related to the AE characteristic parameters. The results show that the energy attenuates to a large extent after the signal propagates through the structure interfaces, and it is also proved that adding coupling agent at the interface is beneficial to the signal propagation. The attenuation coefficient established by this method is very useful to analyze the propagation characteristics of fault signals in complex structures.