An Experimental Analysis for Damage Monitoring in Glass Fiber/Epoxy Composites During Fatigue Tests by Acoustic Emission.

As a non-destructive technique, Acoustic emission (AE) can be employed to detect the damage inside the material passively and then locate the damage source. However, fatigue loading poses challenges to AE signal acquisition and processing. In this paper, AE monitoring is performed on glass fiber/epoxy composite laminates under fatigue loads. Due to the intrinsic noise, wavelet packet decomposition is used for noise elimination. Results show that the noise components in original AE signals can be effectively eliminated by the wavelet analysis. Based on the difference of the arrival times, the line positioning method is shown to locate AE sources appearing in the laminates successfully. The peak frequency characteristic of each AE signal is utilized for damage mode classification. The fracture of the laminate is governed by delamination and fiber/breakage, followed by fiber/matrix interface debonding. [ABSTRACT FROM AUTHOR]