A Gradient Vector Descent Strategy for Localizing Acoustic Emission Sources in Discontinuous Structures With a Hole

The analysis of acoustic signals to localize acoustic emission (AE) sources has emerged as a kind of favored approach. Despite recent advances, the task of localizing AE sources such as impacts in the discontinuous structure with a hole still poses a considerable challenge. A localizing method based on the gradient vector descent method is presented in this article, which is applied to a discontinuous structure with a hole. When an impact event is observed, this method will first calculate the time difference-of-arrival values of different sensors and set the most likely location of impact as origin coordinates. Then, the tracks of acoustic signals on the surface of the structure are calculated by vector analysis, which is used to compute the difference of path for different sensors. The calculated parameters will be used in an objective function; then coordinates of impact will be corrected by the gradient vector descent strategy and difference-of-path values will be recalculated to complete iteration until satisfying the cutoff condition. In addition, simulation and laser Doppler experiments verify the correctness of the propagation path. The experiment results of extensive pencil lead break (PLB) tests on the structure with a hole further indicate that the proposed method can achieve higher localizing accuracy (the average error is 1.034 cm) than traditional methods with a relatively low computational cost.