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Lamb Wave Phase Velocity Imaging of Concrete Plates with 2D Arrays

Tofeldt, Oskar LU and Rydén, Nils LU (2017) In Journal of Nondestructive Evaluation 37(4).
Abstract
In the nondestructive evaluation of concrete structures, ultrasonic techniques are considered to be more capable than low-
frequency techniques such as the impact-echo method. This is especially true with the recent development of ultrasonic
transducers, synthetic apertures, and results in an image form, and because low-frequency techniques are usually limited in
their evaluation to the frequency of one single resonant mode. With the aim of reducing this gap in capabilities, we present
a 2D array and wide-frequency bandwidth technique for Lamb wave phase velocity imaging. The presentation involves a
measurement on a newly cast concrete plate using a hammer and an accelerometer as an example. The key concept of... (More)
In the nondestructive evaluation of concrete structures, ultrasonic techniques are considered to be more capable than low-
frequency techniques such as the impact-echo method. This is especially true with the recent development of ultrasonic
transducers, synthetic apertures, and results in an image form, and because low-frequency techniques are usually limited in
their evaluation to the frequency of one single resonant mode. With the aim of reducing this gap in capabilities, we present
a 2D array and wide-frequency bandwidth technique for Lamb wave phase velocity imaging. The presentation involves a
measurement on a newly cast concrete plate using a hammer and an accelerometer as an example. The key concept of the
technique is the use of 2D arrays that record a full wave field response over a limited surface subdomain within the complete
measurement domain. Through a discrete Fourier transform, a spectral estimate is obtained for the 2D array in the frequency-
phase velocity domain. The variation of the phase velocity is then mapped using a stepwise movement of the 2D array within
the complete measurement domain. With two different types of 2D arrays, the variation of the phase velocity for the A0
Lamb mode is mapped and displayed in a polar and image plot, and low variation is observed for both cases. This result
verifies the expected condition of a homogenous material and plate thickness and, more importantly, highlights the potential
of wide-frequency bandwidth techniques based on full wave field data. (Less)
Please use this url to cite or link to this publication:
author
and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Lamb waves, Imaging, 2D arrays, Concrete, Impact-echo, Full wave field data
in
Journal of Nondestructive Evaluation
volume
37
issue
4
pages
13 pages
publisher
Springer
external identifiers
  • scopus:85040468242
ISSN
1573-4862
DOI
10.1007/s10921-017-0457-x
language
English
LU publication?
yes
id
7de69e8c-ea50-49be-ba79-99f9739ea766
date added to LUP
2018-01-16 15:26:12
date last changed
2022-04-01 21:58:36
@article{7de69e8c-ea50-49be-ba79-99f9739ea766,
  abstract     = {{In the nondestructive evaluation of concrete structures, ultrasonic techniques are considered to be more capable than low-<br/>frequency techniques such as the impact-echo method. This is especially true with the recent development of ultrasonic<br/>transducers, synthetic apertures, and results in an image form, and because low-frequency techniques are usually limited in<br/>their evaluation to the frequency of one single resonant mode. With the aim of reducing this gap in capabilities, we present<br/>a 2D array and wide-frequency bandwidth technique for Lamb wave phase velocity imaging. The presentation involves a<br/>measurement on a newly cast concrete plate using a hammer and an accelerometer as an example. The key concept of the<br/>technique is the use of 2D arrays that record a full wave field response over a limited surface subdomain within the complete<br/>measurement domain. Through a discrete Fourier transform, a spectral estimate is obtained for the 2D array in the frequency-<br/>phase velocity domain. The variation of the phase velocity is then mapped using a stepwise movement of the 2D array within<br/>the complete measurement domain. With two different types of 2D arrays, the variation of the phase velocity for the A0<br/>Lamb mode is mapped and displayed in a polar and image plot, and low variation is observed for both cases. This result<br/>verifies the expected condition of a homogenous material and plate thickness and, more importantly, highlights the potential<br/>of wide-frequency bandwidth techniques based on full wave field data.}},
  author       = {{Tofeldt, Oskar and Rydén, Nils}},
  issn         = {{1573-4862}},
  keywords     = {{Lamb waves; Imaging; 2D arrays; Concrete; Impact-echo; Full wave field data}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{4}},
  publisher    = {{Springer}},
  series       = {{Journal of Nondestructive Evaluation}},
  title        = {{Lamb Wave Phase Velocity Imaging of Concrete Plates with 2D Arrays}},
  url          = {{http://dx.doi.org/10.1007/s10921-017-0457-x}},
  doi          = {{10.1007/s10921-017-0457-x}},
  volume       = {{37}},
  year         = {{2017}},
}