Localization of Acoustic Emission Sources in the Steel Bifurcated Pipe of Hydropower Station

摘要

The paper analyzes and studies the acoustic emission localization of the irregular-shaped and thick-wall steel plate bifurcated pipe of hydropower station. The paper analyzes the effect of acoustic velocity and structural irregularity on localization accuracy of AE source. On the basic of time-frequency analysis of the AE signals, drawing of the Lamb wave dispersion curves, calculation of the group velocity and the phase velocity of the Lamb wave, meanwhile, considering the characteristics of multi-mode and variable velocity of the wave, the paper proposes a method to measure the sound velocity based on linear fitting of TDOA (time difference of arrival) versus distance difference of respective source distances from the two sensors. The Location Uncertainty (LUCY) and location error (LE) analysis of AE location source are also implemented. At the end the proposed velocities of the different area of the steel bifurcated pipe are calculated.