Localisation and identification of fatigue matrix cracking and delamination in a carbon fibre panel by acoustic emission

The use of Acoustic Emission (AE) as a Structural Health Monitoring (SHM) technique is very attractive thanks to its ability to detect not only damage sources in real-time but also to locate them. To demonstrate the AE capabilities on known damage modes, a carbon fibre panel was manufactured with cut fibres in a central location and subjected to fatigue loading to promote matrix cracking. Subsequently, a delamination was created within the panel using an impact load, and the test was continued. AE signals were located within the crack area in the first part of the test. After impact, AE signals were detected from both areas under fatigue loading; signals from this area were located and used for further analysis with the neural network technique. The application of an unsupervised neural network based classification technique successfully separated two damage mechanisms, related to matrix cracking and delamination. The results obtained allowed a more detailed understanding of such sources of AE in carbon fibre laminates.