Non-Destructive Detection of Crack Initiation Using Acoustic Emission

Abstract

One of the major concerns in structures is early detection of a growing crack to prevent fracture, predict remaining useful life, schedule maintenance and reduce costly downtimes. This paper focuses on in-situ monitoring of structural health, specifically detection of small crack growth and crack initiation in structures using Acoustic Emission (AE) technology. Acoustic Emission (AE) is a non-destructive testing (NDT) with potential applications for locating and monitoring fatigue cracks during structural health management. In this paper, the AE signal properties for identifying the presence of a small initial crack is assessed to provide the presence of the onset of a potential growing crack. The approach is based on establishing any association between particular features of AE and fatigue crack initiation. Experimental investigation of uniform cyclic load tests performed on standard fatigue samples of aluminum alloys showed that certain properties of the AE events noticeably change after crack initiation. It was concluded that AE technology can successfully detects crack initiation. The proposed method has significant potential to be used for in-situ monitoring and evaluation of health of structures.