A Comparison Between Time-of-Arrival and Novel Phased Array Approaches to Estimate Acoustic Emission Source Locations in a Steel Plate

An important step in quantitative acoustic emission (AE) monitoring is the estimation of the temporal and spatial coordinates of the source. In this paper, we describe and compare two AE source location approaches: traditional time of arrival and a novel circular phased array. Both of these approaches have their strengths and limitations depending on the application. The novelty of our phased array approach is that we employ two circular arrays, which enables us to estimate the location rather than only the direction of the source, a limitation of traditional phased array approaches that only use one array. Results of laboratory experiments performed on a steel plate according to ASTM E647 using novel multi-sensor sheets to record the AE signals are presented and discussed for both approaches. Each sheet was equipped with a dense array of piezoelectric discs laminated on a polyimide substrate. The sheets were mounted on one side of the steel plate and pencil lead breaks applied to the other side representing artificial sources of AE. The results are presented and discussed and a comparison between the performances of the two approaches is provided.