Source location in thin plates using cross-correlation

In this paper an alternative method to first threshold crossing for acoustic emission (AE) source location is presented. For wave propagation in dispersive media, the accuracy of source location can be improved by locating corresponding phase points on the transducer outputs to determine the difference in arrival times. The phase point location was done by cross-correlating the transducer outputs with a single frequency cosine wave modulated by a Gaussian pulse. Experiments were performed using a lead break as the AE source on the surface of an aluminum plate. Due to the plate geometry and source orientation, the wave produced was highly dispersive. Although this wave was unsuitable for first threshold crossing techniques, the time differences needed for triangulation could be determined using the cross-correlation technique.