Analysis of Acoustic Emission Signals using Wavelet Transformation Technique

Acoustic emission (AE) monitoring is carried out during proof pressure testing of pressure vessels to find the occurrence of any crack growth-related phenomenon. While carrying out AE monitoring, it is often found that the background noise is very high. Along with the noise, the signal includes various phenomena related to crack growth, rubbing of fasteners, leaks, etc. Due to the presence of noise, it becomes difficult to identify signature of the original signals related to the above phenomenon. Through various filtering/thresholding techniques, it was found that the original signals were getting filtered out along with noise. Wavelet transformation technique is found to be more appropriate to analyse the AE signals under such situations. Wavelet transformation technique is used to de-noise the AE data. The de-noised signal is classified to identify a signature based on the type of phenomena.