305 / 2025-06-19 21:22:19

An optimized ultrasonic guided wave defect location approach based on the wavelet energy entropy

Lamb wave,wavelet energy entropy,elliptical imaging algorithm

Ultrasonic guided waves are often used for detecting defects in plate structures. However, the generation of Lamb waves is closely related to the temperature of environment, the thickness of adhesive layer, the measurement error of instruments, and other factors, which will lead to artifacts in defect location images. Therefore, how to use measured signals to achieve the suppression of artifacts is a pressing issue. In this paper, to improve the accuracy of positioning results, using not only time domain information, the change in the frequency spectrum of monitoring signals before and after occurrence of a defect was also studied. Based on the quantification of the change in amplitude-frequency characteristics, a weighed elliptical imaging algorithm for defect detection was proposed. First, the influence of a round through-hole defect on the signal of the damaged plate was estimated. Then, the wavelet energy entropy was applied to quantify the change in the frequency domain before and after occurrence of a defect, and a new index called “path weighting” was developed to weight the ellipses in elliptical imaging algorithm for defect detection. Finally, an experiment was conducted to verify the location accuracy of the proposed method, and the experimental results show that artifacts can be significantly suppressed.