Acoustic Emission source location based on Modal Analysis and Wavelet Transform about three-dimensional braided composites

In this paper, Acoustic Emission (AE) technique, which is widely used in damage detection of three-dimensional (3-D) braided composites, is combined with modal analysis and wavelet transform theory to locate the damage position. The AE signals of 3-D braided composites have characteristics of multi-mode and dispersion. So AE source location should be based on the same mode and frequency guided wave's arrival time and transmission speed to sensors. According to wavelet transform theory, AE signals with noise were processed with the following three steps. First, feature extract and noise filtering are performed through multi-scale analysis, decomposition and reconstruction of signals. Second, Gabor wavelet transform is applied to the guided wave at the same frequency and modal. Basing on the transform results location analysis is made at last. There is an experiment about tabular carbon fiber bundle composites to demonstrate the feasibility of this method.