文献类型：期刊文献

英文题名：Wavefield imaging of nonlinear ultrasonic Lamb waves for visualizing fatigue micro-cracks

作者：Xu, Haiming[1];Liu, Lishuai[1];Li, Xuan[1];Xiang, Yanxun[1];Xuan, Fu-Zhen[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai Key Lab Intelligent Sensing & Detect Tech, Shanghai 200237, Peoples R China

年份：2024

卷号：138

外文期刊名：ULTRASONICS

收录：;EI(收录号：20234915170955);WOS:【SCI-EXPANDED(收录号:WOS:001135430100001)】；

基金：This work was supported by the National Key Research and Devel- opment Program of China (Grant No. 2022YFF0605600) , the National Natural Science Foundation of China (Grant Nos. 12025403, 12374434, and 12104155) , and the Shanghai Chenguang Program (Grant No. 21CGA36) .

语种：英文

外文关键词：Closed fatigue crack; Nonlinear Lamb waves; Laser interferometer; Wavefield data

摘要：The traditional nonlinear ultrasonic technique, as typified by the second-harmonic generation and the frequency mixing response, can be employed to identify and characterize the micro-damage. However, the research on micro-damage characterization using nonlinear Lamb wave imaging technique remains an ongoing challenge and is rarely reported. A method called standardized amplitude difference is proposed for nonlinear feature enhancement, and further for fatigue crack imaging based on the wavefield data. Wavefield data contain abundant information on the spatial and temporal variation of propagating waves in the damaged structure. The nonlinearity index beta ' of the signal difference under the high and low incident wave amplitudes is calculated for fatigue crack imaging. Two scanning methods, including local scanning and global scanning, are introduced to image the fatigue crack tip and visualize the wave field of the harmonics respectively. The experimental validation, based on the imaging results of an aluminum alloy plate specimen with a barely visible fatigue crack and a steel plate with a blind hole, manifests that the proposed method can be used to enhance and extract the nonlinear features and suppress the fundamental frequency, so as to improve the signal-to-noise ratio (SNR) of the micro-damage imaging results.