Predictive acoustic emission in fracture and fatigue.

Current investigations of the correlation between acoustic emission characteristics, such as total count, count rate, amplitude distribution and frequency spectra with fracture toughness and fatigue crack initiation and propagation have led to conclude that similar mechanisms govern the fracture process and the occurrence of acoustic emission. This conclusion is encompassing for both brittle and ductile fracture behaviour. Because fracture criteria, drawn from fracture mechanic concepts, exist for characterization of both fracture and fatigue of metallic meterials, it is possible to use acoustic emission to determine the extent of damage and the life of a structure. This paper presents a detailed description of this process leading to development of a predictive approach to acoustic emission activity from a structure subjected to fracture and/or fatigue cyclic loading.