汇报题目：参加QNDE 2018国际会议总结报告会
汇报时间：2018年7月23日(星期一) 9:00
汇报地点：科技园西五楼南205会议室
汇报人：黄利平
会议名称：45thAnnual Review of Progress in Quantitative Nondestructive Evaluation
会议时间：July15-19,2018
会议地点：Burlington, Vermont, USA
会议简介：QNDE is a highly interdisciplinary technology that involves the use of various techniques to detect both manufacturing and service related flaws in materials and structures which are important to safety in essentially all industries. The Annual Review is a week-long technical meeting in which both advances in fundamental knowledge and new engineering applications in several measurement technologies - ultrasonics, eddy currents,X-rays, thermosonics and thermography, among others - are reported and discussed. For more than four decades, the QNDE Conference has been identified as the world's leading research/engineering conference in this specialized engineering field.
会议交流工作
Oral presentation: Baseline-Free Damage Detection of Composite Laminates By Using Time Reversal of Lamb Waves
报告人：黄利平
参加论文信息
Title: Baseline-Free Damage Detection of Composite Laminates By Using Time Reversal of Lamb Waves
Author: Liping Huang, Liang Zeng, Jing Lin
Abstract: A structural health monitoring (SHM) system is developed for damage detection in composite laminates. Most lamb wave-based SHM techniques are rely on reference signal, which are significantly influenced by the environmental and operation conditions. Time reversal (TR) is a baseline-free method, which is widely used for Lamb wave-based SHM system. According to the principle of TR, an input signal can be reconstructed at the actuator location if a response signal captured by a sensor is re-emitted back to the actuator after being reversed in the time domain. Damage diagnosis based on Lamb wave TR relies on the fact that the time reversibility will be broken down when a certain type of defect exists along a wave propagation path. Hence, damage can be diagnosed by comparing the waveform of the reconstructed signal with that of the original input signal. However, the time interval of the response signal components for re-emitted and reconstructed signal components for comparison, which are difficult to determine, have great influence on the accuracy of TR. To simplify the extraction of these two signal components, a time-frequency based method is proposed. The short-time Fourier transform (STFT) and an effective local maximum method are used to filter out the desired mode components from broadband Lamb wave signal. Subsequently, the desired narrow-band response and reconstructed signal can be easily calculated without determining the starting and ending time of the extract time interval. The effectiveness of the time-frequency based TR algorithm and its application are verified by experiments. The results show that the accuracy of the time reversal method (TRM) are significantly enhanced.
