Advanced Acoustic Emission Signal Processing Techniques for Structural Health Monitoring

Innovation in material science and the introduction of new structural materials into the commercial and industrial market are forcing researchers to look for modern, sophisticated and advanced structural monitoring tools. The Acoustic Emission (AE) technique is one of the most widely used Structural Health Monitoring (SHM) tools. Despite its remarkable advantages over all other passive Non-Destructive Evaluation (NDE) tools, its applicability is constantly being questioned. This is due to the complex time-frequency characteristics of acoustic waves, especially when used in highly noisy environments or highly non-homogeneous structures. In this study, an advanced signal processing technique is used to analyse the acoustic signals generated by different failure modes of composite specimens. A novel procedure is proposed to extract the Time of Arrival (ToA) of the AE signals. This approach uses a modified version of the Akaike Information Criterion (AIC), which is applicable also to signals with a low signal-to-noise ratio. The proposed method is tested on the AE signals generated from the static tensile test of the syntactic foam, cenosphere-reinforced unsaturated polyester composites. The ToA of the AE signals successfully identifies the damage evolution stages in the syntactic foam.