start-ver=1.4
cd-journal=joma
no-vol=23
cd-vols=
no-issue=1
article-no=
start-page=380
end-page=
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2022
dt-pub=20221229
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Thickness Measurement at High Lift-Off for Underwater Corroded Iron-Steel Structures Using a Magnetic Sensor Probe
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=Infrastructure facilities that were built approximately half a century ago have rapidly aged. Steel sheet piles, the inspection object in this study, are severely corroded, resulting in cave-in damages at wharfs. To solve such a problem, non-destructive inspection techniques are required. We previously demonstrated plate thickness measurement using extremely low-frequency eddy current testing. However, when the steel sheet piles are located in water, shellfish adhere to their surface, causing a lift-off of several tens of millimeters. Therefore, this large lift-off hinders the thickness measurement owing to fluctuations of magnetic signals. In this study, sensor probes with different coil diameters were prototyped and the optimum size for measuring steel sheet piles at high lift-off was investigated. Using the probes, the magnetic field was applied with a lift-off range from 0 to 80 mm, and the intensity and phase of the detected magnetic field were analyzed. Subsequently, by increasing the probe diameter, a good sensitivity was obtained for the thickness estimation with a lift-off of up to 60 mm. Moreover, these probes were used to measure the thickness of actual steel sheet piles, and measurements were successfully obtained at a high lift-off.
en-copyright=
kn-copyright=

en-aut-name=AdachiShoya
en-aut-sei=Adachi
en-aut-mei=Shoya
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=HayashiMinoru
en-aut-sei=Hayashi
en-aut-mei=Minoru
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=KawakamiTaisei
en-aut-sei=Kawakami
en-aut-mei=Taisei
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=AndoYuto
en-aut-sei=Ando
en-aut-mei=Yuto
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=WangJin
en-aut-sei=Wang
en-aut-mei=Jin
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=SakaiKenji
en-aut-sei=Sakai
en-aut-mei=Kenji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

en-aut-name=KiwaToshihiko
en-aut-sei=Kiwa
en-aut-mei=Toshihiko
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=7
ORCID=

en-aut-name=IshikawaToshiyuki
en-aut-sei=Ishikawa
en-aut-mei=Toshiyuki
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=8
ORCID=

en-aut-name=TsukadaKeiji
en-aut-sei=Tsukada
en-aut-mei=Keiji
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=9
ORCID=

affil-num=1
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=

affil-num=2
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=

affil-num=3
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=

affil-num=4
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=

affil-num=5
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=

affil-num=6
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=

affil-num=7
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=

affil-num=8
en-affil=Department of Civil, Environmental and Applied System Engineering, Faculty of Environmental and Urban Engineering, Kansai University
kn-affil=

affil-num=9
en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University
kn-affil=
en-keyword=eddy current testing
kn-keyword=eddy current testing
en-keyword=high lift-off thickness measurement
kn-keyword=high lift-off thickness measurement
en-keyword=magnetic sensor
kn-keyword=magnetic sensor
en-keyword=corrosion
kn-keyword=corrosion
en-keyword=underwater steel structure
kn-keyword=underwater steel structure
END