Damage characterization in composite materials using acoustic emission signal-based and parameter-based data

Damage propagation in DCB specimens is characterized by Acoustic Emission (AE) Technique. Signal-based AE data is used to relate the Mechanical Property of the Material with the Acoustic Activity; Sentry function is used to relate the Strain Energy and Acoustic Energy. The cumulative acoustic energy provides information about the critical points before failure in each specimen. Nonetheless, it was observed that the Sentry function reveals concealed information about the damage propagation and material deterioration which are concealed in the Load-Displacement curve. Sentry function can be used to characterize the damage propagation in the material even before its critical point of failure. The signal-based data, the wavelets, are decomposed into different levels using the Wavelet Packet Transform (WPT). These WPT results discriminate the different frequency band associated with the different types of damage propagation. The false signals from both the mechanical results and acoustic results can be identified using the WPT results.