Excitation of single-mode Lamb waves at high-frequency-thickness products
Author(s)
Khalili, P
Cawley, P
Type
Journal Article
Abstract
Guided wave inspection is used extensively in petrochemical plants to check for defects such as corrosion. Long-range low-frequency inspection can be used to detect relatively large defects, while higher frequency inspection provides improved sensitivity to small defects, but the presence of multiple dispersive modes makes it difficult to implement. This paper investigates the possibility of exciting a single-mode Lamb wave with low dispersion at a frequency thickness of around 20 MHz-mm. It is shown by finite element (FE) analysis backed up by experiments that a signal dominated by the A1 mode can be generated, even in a region where many modes have similar phase velocities. The A1 mode has relatively little motion at the plate surface which means that only a small reflection is generated at features such as T-joints; this is verified numerically. It is also expected that it will be relatively unaffected by surface roughness or attenuative coatings. These features are very similar to those of the higher order mode cluster (HOMC) reported by other authors, and it is shown that the A1 mode shape is very similar to the deflected shape reported in HOMC.
Date Issued
2016-02-01
Date Acceptance
2015-12-08
Citation
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2016, 63 (2), pp.303-312
ISSN
0885-3010
Publisher
Institute of Electrical and Electronics Engineers
Start Page
303
End Page
312
Journal / Book Title
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Volume
63
Issue
2
Copyright Statement
© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Identifier
https://ieeexplore.ieee.org/document/7352350
Subjects
Science & Technology
Technology
Acoustics
Engineering, Electrical & Electronic
Engineering
Excitability
fast Fourier transform (FFT)
guided waves
higher order mode cluster (HOMC)
modal decomposition
FUNDAMENTAL TORSIONAL MODE
GUIDED-WAVES
PIPES
REFLECTION
INSPECTION
NOTCHES
DISPERSION
SCATTERING
DEFECTS
RAIL
Acoustics
02 Physical Sciences
09 Engineering
Publication Status
Published
Date Publish Online
2015-12-10