On the scattering of longitudinal elastic waves from axisymmetric defects in coated pipes

Kirby, R; Zlatev, Z; Mudge, P

On the scattering of longitudinal elastic waves from axisymmetric defects in coated pipes

Kirby, R

Zlatev, Z Mudge, P

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Publication Type:: Journal Article
Citation:: Journal of Sound and Vibration, 2013, 332 (20), pp. 5040 - 5058
Issue Date:: 2013-09-30

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Field	Value	Language
dc.contributor.author	Kirby, R https://orcid.org/0000-0002-3520-1377	en_US
dc.contributor.author	Zlatev, Z	en_US
dc.contributor.author	Mudge, P	en_US
dc.date.issued	2013-09-30	en_US
dc.identifier.citation	Journal of Sound and Vibration, 2013, 332 (20), pp. 5040 - 5058	en_US
dc.identifier.issn	0022-460X	en_US
dc.identifier.uri	http://hdl.handle.net/10453/114509
dc.description.abstract	Viscoelastic coatings are widely used to protect pipelines from their surrounding environment. These coatings are known to attenuate ultrasonic waves guided along the pipe walls, which may limit the range of a pulse/echo based inspection technique that seeks to detect defects in a pipeline. This article aims to investigate the attenuation of longitudinal modes in a coated pipe by comparing predicted and measured values for the reflection coefficient of an axisymmetric defect in a pipe coated with bitumen. This extends recent work undertaken by the authors for torsional modes, and also provides an independent investigation into the validity of those values proposed by the authors for the shear properties of bitumen, based on a comparison between prediction and experiment for torsional modes. Predictions are generated using a numerical mode matching approach for axially uniform defects, and a hybrid finite element based method for non-uniform defects. Values for the shear and longitudinal properties of bitumen are investigated and it is shown that the shear properties of the viscoelastic material play a dominant role in the propagation of longitudinal modes in a coated pipeline. Moreover, by using the shear values obtained from experiments on torsional modes, it is shown that good agreement between prediction and measurement for uniform and non-uniform defects may also be obtained for the longitudinal L(0,2) mode. This provides further validation for the shear bulk acoustic properties proposed for bitumen in the low ultrasonic frequency range, although in order to apply this methodology in general it is demonstrated that one must measure independently the reflection coefficient of both the torsional T(0,1) and the longitudinal L(0,2) mode before arriving at values for the shear properties of a viscoelastic material. © 2013 Elsevier Ltd.	en_US
dc.relation.ispartof	Journal of Sound and Vibration	en_US
dc.relation.isbasedon	10.1016/j.jsv.2013.04.039	en_US
dc.subject.classification	Acoustics	en_US
dc.title	On the scattering of longitudinal elastic waves from axisymmetric defects in coated pipes	en_US
dc.type	Journal Article
utslib.citation.volume	20	en_US
utslib.citation.volume	332	en_US
utslib.for	091301 Acoustics and Noise Control (excl. Architectural Acoustics)	en_US
utslib.for	02 Physical Sciences	en_US
utslib.for	09 Engineering	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
utslib.copyright.status	open_access
pubs.issue	20	en_US
pubs.publication-status	Published	en_US
pubs.volume	332	en_US

Abstract:

Viscoelastic coatings are widely used to protect pipelines from their surrounding environment. These coatings are known to attenuate ultrasonic waves guided along the pipe walls, which may limit the range of a pulse/echo based inspection technique that seeks to detect defects in a pipeline. This article aims to investigate the attenuation of longitudinal modes in a coated pipe by comparing predicted and measured values for the reflection coefficient of an axisymmetric defect in a pipe coated with bitumen. This extends recent work undertaken by the authors for torsional modes, and also provides an independent investigation into the validity of those values proposed by the authors for the shear properties of bitumen, based on a comparison between prediction and experiment for torsional modes. Predictions are generated using a numerical mode matching approach for axially uniform defects, and a hybrid finite element based method for non-uniform defects. Values for the shear and longitudinal properties of bitumen are investigated and it is shown that the shear properties of the viscoelastic material play a dominant role in the propagation of longitudinal modes in a coated pipeline. Moreover, by using the shear values obtained from experiments on torsional modes, it is shown that good agreement between prediction and measurement for uniform and non-uniform defects may also be obtained for the longitudinal L(0,2) mode. This provides further validation for the shear bulk acoustic properties proposed for bitumen in the low ultrasonic frequency range, although in order to apply this methodology in general it is demonstrated that one must measure independently the reflection coefficient of both the torsional T(0,1) and the longitudinal L(0,2) mode before arriving at values for the shear properties of a viscoelastic material. © 2013 Elsevier Ltd.

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http://hdl.handle.net/10453/114509