Performance Investigation of Two AE Source Location Techniques on a Planar Multilayer Structure

The comparisons of an AE source location performance of two widely used methods, time of arrival (TOA) and difference of arrival time (DOAT) have been analyzed in a complex planar multilayered surface. The complex surface has been prepared by covering a steel plate (SM400A) with a multilayered rubber material (Natural Rubber). The purpose of using this structure has been defined to get the comparable AE source location performance in a complicated signal propagation pathway. Both source location techniques have been conducted in a simulated AE wave propagating plane (300 mm * 200 mm in size) under Hsu-Nielsen method. Investigations reveal that the TOA technique gives several erroneous results along with good results. However, the DOAT method has produced all excellent results, even when using a complex surface. It was found since the TOA method is sensitive to constant velocity continuity, the present complex pathway leads to the velocity discontinuity, and thus, several incorrect results have been found. On the other hand, the DOAT method is dependent on the arrival time difference only, and therefore, it shows a higher performance in the source location, even in the presence of a complex structure.