Damage detection of thick plates using trailing pulses at large frequency-thickness products

Trailing pulses, which are Lamb waves generated at large frequency-thickness (fd) products, act like a list of longitudinal pulses with constant time interval. These longitudinal pulses with short wave length are a promising tool for detection of damage in thick plates. However, the waveform complexity of trailing pulses brings challenges. In this paper, a damage detection method for thick plates using trailing pulses at large frequency-thickness products is introduced. Firstly, the characteristics of trailing pulses, including slightly change of velocity and pulse splitting, are discussed from the aspects of ray tracing and approximate analytical solution. Then, a blind pulse compression method for trailing pulses is interpreted, which doesn't need the prior knowledge of material properties. A compression item is designed for trailing pulses. Finally, an experiment is implemented on a thick aluminum plate with three Side Drilled Holes (SDHs), in which all the SDHs are recognized with accurate position estimation. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This paper introduces a method for damage detection in thick plates using trailing pulses, discussing the characteristics of trailing pulses and a blind pulse compression method. Experimental results show accurate identification of all Side Drilled Holes (SDHs) in a thick aluminum plate.