New approach for location of continuously emitting acoustic emission sources by phase-controlled probe arrays

Usually burst-like emission (AE) is localized by triangulation. For continuos AE, e.g. from leakages, this method is not feasible. Therefore a new method for localization of continuous AE has been developed. It is based on a phase-controlled probe array which consists of many single sensor elements. The AE signals received by the different sensor elements are delayed according to their time-off-flight differences from the source to the single elements of the receiver array. By choosing special combinations of time differences between the array elements the directivity pattern of the sensivity of the array can be changed, e.g. rotated in the plane of a large plate. Thus, the source direction can be determined by one array. Some preliminary experiments with an artificial noise source, positioned on a large steel plate, have been performed and have demonstrated the feasibility of this approach.