Title of Paper:Non destructive testing thickness measurement by laser ultrasound under high temperature

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Affiliation of Author(s):自动化学院

Journal:Optik

Abstract:Corrosion is one of the main failure modes of pressure vessel, of which the inspection is mainly conducted through the thickness measurement. Due to the limitation of current testing methods, most of the equipment needs to be shut down and maintained. In this paper, a non-contact thickness measurement based on laser ultrasound is introduced, which can realize the on-line thickness detection under high temperature. Based on the theory of laser ultrasound, effects of high temperature on the longitudinal wave are discussed. The simulation signals of models with different thickness at different temperatures are obtained, and the results show that the velocity of longitudinal wave will decrease with the increase of temperature. Ultrasonic wave is excited on one side of material and the interferometer is used to collect ultrasonic wave on the same side in the experiment. Since the noise-signal ratio of the original signal is low, the collected raw signal is processed by wavelet denoising. In order to obtain the temporal information of longitudinal wave, three spline interpolation and cross-correlation algorithm are used to process the de-noised signal. The temporal information of longitudinal wave can be obtained from the processed signal, and the thickness of the material can be calculated by using the time interval between different longitudinal waves. The results of this study provide a good theoretical and experimental basis for the industrial application of petrochemical industry. © 2018 Elsevier GmbH

ISSN No.:0030-4026

Translation or Not:no

Date of Publication:2018-11-01

Co-author:Li, Suyuan,grp,Zhao, Jiyuan,Zheng, Kai,xj,Chen, Shuai,jyy

Correspondence Author:Haitao Wang