Localization of acoustic emission sources in tensile and ct specimens using a broadband acquisition technique

The acoustic emission sources in a conventional cylindrical tensile test sample of short transversely-cut carbon manganese steel are localized. There is not always a good correlation between the localization of the first signals and the zone which eventually fractures. During the Lüder's plateau, the ae signals are emitted in the deformation band and, in the hardening range, there is no significant ae in the gauge length of the sample. In ct samples precracked by fatigue, the signals are due to the growth of the plastic zone around the crack tip, and the plastic zone size, measured by source localization, agrees with those provided by models derived from fracture mechanics.