Adaptive echo suppression method based on affine projection algorithm in acoustic emission detection

Acoustic emission (AE) technology is popularly applied to damage detection. Boundary reflection of the AE signal is believed as a reason of detecting error. The objective of this work is to propose an adaptive filter method for single source damage detection to eliminate the echo component in the acoustic emission sensor signal and obtain a pure AE signal for the subsequent damage analysis. In this paper, we present the frame model of the adaptive echo suppression system. Two adaptive filtering algorithm-normalized least mean squares (NLMS) algorithm and affine projection algorithm (APA) are applied to estimate the coefficients of the reflection path. Based on these theories, we propose an adaptive echo suppression (AES) method for AE sensor signals and verify its effectiveness by experiments. The results show that the APA-based AES method has faster convergence rate, smaller residual error and better filter performance than the NLMS-based AES method.