Title: Time difference mapping method for locating the acoustic emission source in a composite plate

Author(s): LIU Zenghua; PENG Qiuling; HE Cunfu; WU Bin

Affiliation(s): College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology

Abstract: In the study, an improved time difference mapping (I-TDM) method is proposed to locate the acoustic emission (AE) source in a composite plate. The acoustic velocity in a composite plate with fiber fractures and matrix crack defects largely varies with the propagation direction. In the proposed method, the prebuilt database is adopted in order to avoid the consideration of the inconsistent propagation speed of waves in a plate. In addition, according to the proposed method, the requirements for wave propagation modes or the sensor layout are not strict in the experiment. Firstly, in order to quickly and accurately select and delete the pseudo AE events in a large number of AE data, the clustering algorithm was used to automatically identify and select the highly correlated AE events on each grid node and construct a time difference training database. Secondly, the interpolation compensation algorithm was adopted to increase grid density and improve grid resolution. Finally, the actual location of the source in the test area was verified by using the weighted difference algorithm. Theoretical analysis and experimental results showed that the average location error of the sound source obtained by the I-TDM method was 18.0 mm, which was lower than that obtained by the traditional time difference mapping (TDM) method, 26.5 mm. After the I-TDM method was adopted, the corresponding average relative error was reduced from 5.3% to 3.6% and the overall running time was reduced from 5 h to 16.87 s. The I-TDM method can effectively improve the location precision of the sound source in a composite plate.