Experimental and Computational Analysis of Acoustic Emission Waveforms for SHM Applications

Abstract

Acoustic emission (AE) waveform monitoring has a great potential to use as an SHM technology. The design of an SHM system requires a thorough understanding not only in the AE hit level but also in the waveform level. Capturing the fatigue-crack generated acoustic waves from a thin aircraft material is a challenging task. The present work focuses on capturing the AE waveform from the fatigue-crack of the thin specimen. The capability of the piezoelectric wafer active sensor (PWAS), commonly used for SHM design, in capturing the fatigue-crack AE has been illustrated. The AE waveforms were captured from an in-situ AE-fatigue experiment. The AE waveforms were analyzed and two distinct types of AE waveforms were frequently observed. Multiphysics FEM simulations also showed the two types of AE waveforms corresponding to the two types of AE events. The local interaction of the AE waveform with the fatigue-crack was also observed that was yet to capture experimentally. The concept of seismological moment tensor seemed to work to simulate the AE source in the thin structure. It has been shown that different components of moment tensor can successfully simulate the different groups of experimental AE waveforms