Micro-Sized Pinhole Inspection with Segmented Time Reversal and High-Order Modes Cluster Lamb Waves Based on EMATs  

作　　者：Jinjie Zhou Yang Hu Xiang Li Yang Zheng Sanhu Yang Yao Liu 

机构地区：[1]School of Mechanical Engineering,North University of China,Taiyuan,030051,China [2]School of Aeronautics and Astronautics,University of Electronic Science and Technology of China,Chengdu,611731,China [3]China Special Equipment Inspection and Research Institute,Beijing,100029,China

出　　处：《Chinese Journal of Mechanical Engineering》2023年第1期224-236,共13页中国机械工程学报（英文版）

基　　金：National Natural Science Foundation of China(Grant No.62071433);National Key R&D Program of China(Grant No.2022YFC3005002)。

摘　　要：Pinhole corrosion is difficult to discover through conventional ultrasonic guided waves inspection,particularly for micro-sized pinholes less than 1 mm in diameter.This study proposes a new micro-sized pinhole inspection method based on segmented time reversal(STR)and high-order modes cluster(HOMC)Lamb waves.First,the principle of defect echo enhancement using STR is introduced.Conventional and STR inspection experiments were conducted on aluminum plates with a thickness of 3 mm and defects with different diameters and depths.The parameters of the segment window are discussed in detail.The results indicate that the proposed method had an amplitude four times larger than of conventional ultrasonic guided waves inspection method for pinhole defect detection and could detect micro-sized pinhole defects as small as 0.5 mm in diameter and 0.5 mm in depth.Moreover,the segment window location and width(5-10 times width of the conventional excitation signal)did not affect the detection sensitivity.The combination of low-power and STR is more conducive to detection in different environments,indicating the robustness of the proposed method.Compared with conventional ultrasonic guided wave inspection methods,the proposed method can detect much smaller defect echoes usually obscured by noise that are difficult to detect with a lower excitation power and thus this study would be a good reference for pinhole defect detection.

关 键 词：Pinhole corrosion High-order modes cluster Lamb waves Segmented time reversal inspection Electromagnetic acoustic transducer 

分 类 号：TG172[金属学及工艺—金属表面处理] TG115.285[金属学及工艺—金属学]