Characterization of Acoustic Emission Signals from Mode I Crack

Abstract

Separation of crack growth signals is of fundamental importance for detecting, locating, and determining the significance of an internal flaw using acoustic emission techniques. The methodology used to determine the acoustic emission signal in this paper incorporates a source model that is an actual crack propagation and arrest event. This source model includes the effects of the following physical parameters: location of the crack, crack orientation, crack tip velocity, duration of crack propagation, and mode of fracture. The integral equation method is used to examine a semi‐infinite crack in an infinite, linear elastic body loaded under the conditions of plane strain. The dynamic mode I stress caused by a crack propagating with a prescribed velocity is determined, and then the displacements at any point are calculated. These time‐dependent displacements are the analytical form of the acoustic emission waveforms. Numerical results examine the effect of crack tip velocity, duration of propagation, and distance from the crack source to the point of observation on the calculated acoustic emission signals.