Imaging of Defect Signal of Reinforcing Steel Bar at High Lift-Off Using a Magnetic Sensor Array by Unsaturated AC Magnetic Flux Leakage Testing

Hayashi, Minoru; Kawakami, Taisei; Saito, Taisuke; Sakai, Kenji; Kiwa, Toshihiko; Tsukada, Keiji

doi:10.1109/tmag.2020.3017722

Cited by 15 publications

(2 citation statements)

References 14 publications

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“…Gotoh also used low-frequency AC excitation to increase the penetration depth and detected outer side cracks in a steel plate 3 mm thick [ 106 , 107 ]. Hayashi proposed an unsaturated ACMFL testing method for reinforcing steel bars and achieved defect inspection at high liftoff of up to 100 mm [ 108 ].…”

Section: Excitation and Sensing Techniques In Mfl Testingmentioning

confidence: 99%

A Review of Magnetic Flux Leakage Nondestructive Testing

Feng

et al. 2022

Materials

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Magnetic flux leakage (MFL) testing is a widely used nondestructive testing (NDT) method for the inspection of ferromagnetic materials. This review paper presents the basic principles of MFL testing and summarizes the recent advances in MFL. An analytical expression for the leakage magnetic field based on the 3D magnetic dipole model is provided. Based on the model, the effects of defect size, defect orientation, and liftoff distance have been analyzed. Other influencing factors, such as magnetization strength, testing speed, surface roughness, and stress, have also been introduced. As the most important steps of MFL, the excitation method (a permanent magnet, DC, AC, pulsed) and sensing methods (Hall element, GMR, TMR, etc.), have been introduced in detail. Finally, the algorithms for the quantification of defects and the applications of MFL have been introduced.

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Section: Excitation and Sensing Techniques In Mfl Testingmentioning

confidence: 99%

A Review of Magnetic Flux Leakage Nondestructive Testing

Feng

et al. 2022

Materials

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“…NDT methods mainly include ultrasonic testing (UT), leak testing (LT), AC field measurement (ACFMT), penetration testing (PT), magnetic particle testing (MT), eddy current testing (ECT), radiographic testing (RT), acoustic emission testing (AET), and magnetic flux leakage (MFL) inspection. However, RT, ECT, and MFL examinations are flawed due to radiation exposure and structural limitations [2,3]. UT, as one of the NDT technologies, has the characteristics of rapid detection, wide detection range, high detection accuracy, and good environmental adaptability.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study and Optimal Design of the Butterfly Coil EMAT for Signal Amplitude Enhancement

Zhang

Liu

Jia

et al. 2022

Sensors

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The low energy conversion efficiency of electromagnetic acoustic transducers (EMATs) is a critical issue in nondestructive testing applications. To overcome this shortcoming, a butterfly coil EMAT was developed and optimized by numerical simulation based on a 2−D finite element model. First, the effect of the structural parameters of the butterfly coil EMAT was investigated by orthogonal test theory. Then, a modified butterfly coil EMAT was designed that consists of three−square permanent magnets with opposite polarity (TSPM−OP) to enhance the signal amplitude. Finally, the signal amplitude obtained from the three types of EMATs, that is, the traditional EMAT, the EMAT optimized by orthogonal test theory, and the modified EMAT with TSPM−OP, were analyzed and compared. The results show that the signal amplitude achieved by the modified butterfly coil EMAT with TSPM−OP can be increased by 4.97 times compared to the traditional butterfly coil EMAT.

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