Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Discriminating surface-breaking from subsurface cracks in pressurized water pipes by means of a parametric modulation technique
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
2008 (English)In: NDT & E international, ISSN 0963-8695, E-ISSN 1879-1174, Vol. 41, no 3, 208-216 p.Article in journal (Refereed) Published
Abstract [en]

The discrimination of surface-breaking cracks from cracks that are entirely embedded within the material is paramount to the assessment of the integrity of pressurized water pipes. This work addresses this issue investigating the use of a parametric modulation technique towards this end. Tests are conducted on 1D surface-breaking cracks that are either dry or contain water. The response of these defects is investigated as a function of crack depth and closure, as well as of amplitude and frequency of the modulation. The ensuing results suggest that fluid-filled and dry cracks can be discriminated from each other. The origin of the different response of these defects is discussed in terms of both crack's stiffness and modulation-induced dynamics.

Place, publisher, year, edition, pages
2008. Vol. 41, no 3, 208-216 p.
Keyword [en]
modulation, surface-breaking, crack, ultrasonic waves
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-7891DOI: 10.1016/j.ndteint.2007.09.005ISI: 000253385400008Scopus ID: 2-s2.0-37849042450OAI: oai:DiVA.org:kth-7891DiVA: diva2:13054
Note
QC 20100906Available from: 2008-01-14 Created: 2008-01-14 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Nonlinear Interaction Between Ultrasonic Waves and Cracks and Interfaces
Open this publication in new window or tab >>Nonlinear Interaction Between Ultrasonic Waves and Cracks and Interfaces
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The subject of this thesis is the development of new ultrasound inspection techniques for detection of cracks that are smaller than the wavelength of the inspecting wave and the characterization of cracks in fluid-filled pipes as either surface-breaking or subsurface.

The spectrum of the scattered field of a partially closed crack comprises harmonic components not expected to be found in the case of linear scatterers such as pores or inclusions. Paper A presents an experimental investigation into the linear reflection and generation of the 2nd harmonic component following the incidence of an ultrasonic wave onto a dry or water-confining interface formed by elasto-plastic steel-steel surfaces in contact. The results indicate that water has an unexpected effect on the reflection, at low interfacial pressures, suggesting that fluid mediated forces play a role not accounted for in current models. The level of the generation of the 2nd harmonic measured provides support for further development of the technique for detection of dry, partially closed cracks or fluid-filled, nearly open cracks.

A theoretical model describing the nonlinear scattering of acoustic waves by surface-breaking cracks with faces in partial contact is presented in Paper B. Both linear and nonlinear response of the crack are shown to be the largest for a SV wave incident on the surface containing the crack at an angle just above the critical angle for longitudinal waves.

A method which provides information on whether a fracture is surface-breaking or subsurface has been modelled and its optimal experimental set-up examined in Paper C. The main assumption of the model is that water carried by pressurized pipes infiltrates and fills a surface-breaking crack, while a subsurface crack is dry. The model simulates an inspection in which the modulation technique is employed and the surface hosting the crack is not accessible. A parameter, constructed with signals recorded in backscattering configuration during a modulation cycle, is examined and shown to provide a clear criterion to distinguish subsurface from surface-breaking cracks when a SV wave at 45 degree incidence is employed as a probe.

Finally, in Paper D the modulation technique is experimentally tested on steel beams that host surface-breaking fatigue cracks. The method is shown to be a successful tool to distinguish a dry from a fluid-filled crack. Furthermore, it is revealed that the dynamics of the fluid needs to be accounted for in a more accurate simulation tool.

Place, publisher, year, edition, pages
Stockholm: KTH, 2008. xiii, 32 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2008:01
Keyword
ultrasonic waves, crack, modulation, rough interface, partially closed, surface-breaking, fluid-filled
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-4604 (URN)
Public defence
2008-01-31, Sal F3, F, Lindstedtsvägen 26, Stockholm, 10:00
Opponent
Supervisors
Note
QC 20100906Available from: 2008-01-14 Created: 2008-01-14 Last updated: 2010-09-06Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Poznic, MilanPecorari, Claudio
By organisation
Marcus Wallenberg Laboratory MWL
In the same journal
NDT & E international
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 67 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf