The influence of surface roughness on ultrasonic thickness measurements
File(s)
Published version
Author(s)
Benstock, D
Cegla, F
Stone, M
Type
Journal Article
Abstract
In corrosion assessment, ultrasonic wall-thickness measurements are often presented in the form of
a color map. However, this gives little quantitative information on the distribution of the thickness
measurements. The collected data can be used to form an empirical cumulative distribution function
(ECDF), which provides information on the fraction of the surface with less than a certain thickness.
It has been speculated that the ECDF could be used to draw conclusions about larger areas, from
inspection data of smaller sub-sections. A detailed understanding of the errors introduced by such
an approach is required to be confident in its predictions. There are two major sources of error: the
actual thickness variation due to the morphology of the surface and the interaction of the signal
processing algorithm with the recorded ultrasonic signals. Parallel experimental and computational
studies were performed using three surfaces, generated with Gaussian height distributions. The
surfaces were machined onto mild steel plates and ultrasonic C-scans were performed, while the distributed
point source method was used to perform equivalent simulations. ECDFs corresponding to
each of these surfaces (for both the experimental and computational data) are presented and their
variation with changing surface roughness and different timing algorithms is discussed.
a color map. However, this gives little quantitative information on the distribution of the thickness
measurements. The collected data can be used to form an empirical cumulative distribution function
(ECDF), which provides information on the fraction of the surface with less than a certain thickness.
It has been speculated that the ECDF could be used to draw conclusions about larger areas, from
inspection data of smaller sub-sections. A detailed understanding of the errors introduced by such
an approach is required to be confident in its predictions. There are two major sources of error: the
actual thickness variation due to the morphology of the surface and the interaction of the signal
processing algorithm with the recorded ultrasonic signals. Parallel experimental and computational
studies were performed using three surfaces, generated with Gaussian height distributions. The
surfaces were machined onto mild steel plates and ultrasonic C-scans were performed, while the distributed
point source method was used to perform equivalent simulations. ECDFs corresponding to
each of these surfaces (for both the experimental and computational data) are presented and their
variation with changing surface roughness and different timing algorithms is discussed.
Date Issued
2014-12-01
Date Acceptance
2014-10-14
Citation
Journal of the Acoustical Society of America, 2014, 136 (6), pp.3028-3039
ISSN
0001-4966
Publisher
Acoustical Society of America
Start Page
3028
End Page
3039
Journal / Book Title
Journal of the Acoustical Society of America
Volume
136
Issue
6
Copyright Statement
© 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.
License URL
Subjects
Science & Technology
Technology
Life Sciences & Biomedicine
Acoustics
Audiology & Speech-Language Pathology
POINT-SOURCE METHOD
WAVE-PROPAGATION
FIELD
CORROSION
Publication Status
Published