Extraction Method of Crack Signal for Inspection of Complicated Steel Structures Using A Dual-Channel Magnetic Sensor

Minoru Hayashi, Taisuke Saito, Yoshihiro Nakamura, Kenji Sakai, Toshihiko Kiwa, Izumi Tanikura, Keiji Tsukada

Research output: Contribution to journalArticle

Abstract

Conventional eddy current testing (ECT) using a pickup coil probe is widely employed for the detection of structural cracks. However, the inspection of conventional ECT for steel structures is difficult because of the magnetic noise caused by the nonuniform permeability of steel. To combat this challenge, we have developed a small magnetic sensor probe with a dual-channel tunneling magnetoresistance sensor that is capable of reducing magnetic noise. Applying this probe to a complicated component of steel structures-such as the welds joining a U-shaped rib and deck plate together-requires the reduction of signal fluctuation caused by the distance (liftoff) variations between the sensor probe and the subject. In this study, the fundamental crack signal and the liftoff signal were investigated with the dual-channel sensor. The results showed that the liftoff signals could be reduced and differentiated from the crack signals by the differential parameters of the dual-channel sensor. In addition, we proposed an extraction technique for the crack signal using the Lissajous curve of the differential parameters. The extraction technique could be applied to the inspections not only for flat plates but also for welded angles to detect cracks without the influence of the liftoff signal.

Original languageEnglish
JournalSensors (Basel, Switzerland)
Volume19
Issue number13
DOIs
Publication statusPublished - Jul 8 2019

Fingerprint

steel structures
Magnetic sensors
Steel
Steel structures
inspection
cracks
Inspection
Cracks
Noise
sensors
Eddy current testing
Sensors
Ribs
probes
Tunnelling magnetoresistance
eddy currents
Permeability
Pickups
Joining
combat

Keywords

  • eddy current testing
  • liftoff
  • magnetic sensor
  • steel crack detection

ASJC Scopus subject areas

  • Analytical Chemistry
  • Atomic and Molecular Physics, and Optics
  • Biochemistry
  • Instrumentation
  • Electrical and Electronic Engineering

Cite this

Extraction Method of Crack Signal for Inspection of Complicated Steel Structures Using A Dual-Channel Magnetic Sensor. / Hayashi, Minoru; Saito, Taisuke; Nakamura, Yoshihiro; Sakai, Kenji; Kiwa, Toshihiko; Tanikura, Izumi; Tsukada, Keiji.

In: Sensors (Basel, Switzerland), Vol. 19, No. 13, 08.07.2019.

Research output: Contribution to journalArticle

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