Damage Identification of Pipeline Based on Ultrasonic Guided Wave and Wavelet Denoising

Abstract

Guided wave technology shows excellent capacity in the damage identification of the pipeline. In practical inspection, the detection ability is greatly reduced due to the interference echo signal from the feature structure in the pipeline. In this paper, the propagation models of guided wave in straight pipe and pipe with feature structures are established, and the effect of feature structure on the guided wave echo signal is analyzed, including pipe with an elbow, ring joint, and accessory structure, and the corresponding damage identification strategies for pipe with different forms of features are proposed. The damage index of the echo signal difference and radial displacement signal is proposed to extract the signal from damage. Besides, to eliminate the noise effect caused by the actual detection situation, a novel guided wave denoising method based on the wavelet analysis is studied, and the analysis results indicate that the damage detection strategy based on the guided wave can accurately locate the damage region in both straight pipe and pipe with features and that the proposed denoising method can effectively eliminate the noise in the echo signal.