Coupling pulse eddy current sensor for deeper defects NDT

Xie, Lian; Gao, Bin; Tian, Guohui; Tan, Jidong; Feng, Bo; Yin, Ying

doi:10.1016/j.sna.2019.03.029

Cited by 61 publications

(20 citation statements)

References 22 publications

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“…A primary magnetic field is established in an axial direction around the coil. This elec-trical current then creates its own secondary magnetic field, which is opposite in direction at all times and opposes the coil's magnetic field in accordance with Lenz's Law, as illustrated in Figure 5 [20]. The interaction between the magnetic field generated by the coil and the magnetic field generated by eddy currents is then examined with sensors or coils.…”

Section: Eddy Current (Ec)mentioning

confidence: 99%

Nondestructive Testing for Corrosion Evaluation of Metal under Coating

Zhang

Yang

et al. 2021

Journal of Sensors

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The use of steel has grown rapidly over the past decades. However, corrosion under coating detection still presents challenges for nondestructive testing (NDT) techniques. One of such challenges is the lift-off introduced by complex structures. Inaccessibility due to structure leads corrosion to be undetected, which can lead to catastrophic failure. Furthermore, lift-off effects reduce the sensitivities. The limitations of existing NDT techniques heighten the need for novel approaches to the characterization of corrosion. This paper begins with a discussion of the challenges associated with corrosion detection of metal under coating. Secondly, reviews are given of the most NDT methods used for the detection of corrosion under coating. The different techniques based on nondestructive testing methods such as ultrasonic, acoustic, electromagnetic, radiographic, and thermographic have been detailed out. This review presents the significance and advantages provided by the emerging NDT techniques. In the end, the trends and identified problems are summarized.

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Section: Eddy Current (Ec)mentioning

confidence: 99%

Nondestructive Testing for Corrosion Evaluation of Metal under Coating

Zhang

Yang

et al. 2021

Journal of Sensors

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“…It is from the induced voltage in the Rx (coil) that the status of the test sample is evaluated. However, the total field in the presence of a sample can be considered as a sum of the original field of the coil in the air plus a reflected field from the metal sample [11,32,33]. In presence of a sample to a Tx-Rx probe, there are self-couplings of both Tx (coil) and Rx (coil) through the sample ℒ1, ℒ2 and a mutual coupling of Tx and Rx (coils) through the sample ℳ (remote coupling).…”

Section: Analysis Of Equivalent Circuit Of Tx-rx Pec Probementioning

confidence: 99%

Investigation of Signal Conditioning for Tx-Rx PEC Probe at High Lift-Off Using a Modified Maxwell’s Bridge

2020

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Pulsed eddy current testing is widely used because of its richness in spectral components. However, the degrading sensitivity as lift-off increases poses a challenge to its application in thick insulation or buried structures and weld areas. In the transmitter-receiver probe, self-impedance (offset) of receiver coil dominates the output signal, reducing the signal-to-noise ratio, especially at high lift-off. This limits the subsequent amplification of the output signal by the signal conditioning circuit. In practice, bridge-based measurements are used to mitigate this challenge but result in small linear range inputoutput characteristics. Electromagnetic interference and stray capacitance effects also cause measurement errors. This paper investigates a modified Maxwell's inductance bridge based on operational amplifier configuration for high lift-off testing. The receiver coil self-impedance is removed to improve signal-tonoise ratio and to make output signal proportional to impedance change only. Experiments are performed to evaluate the performance of the circuit in crack detection. The results show improved signal-to-noise ratio with maximum linearity deviation of 0.30%, and a higher crack detection sensitivity at 30mm high lift-off, in comparison to the conventional bridge circuit with maximum linearity deviation of 0.53%.

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“…PECT is sensitive to surface and near-surface crack detection. However, it is difficult to detect internal failure due to the skin effect [3–5]. MT is effective at detecting surface crack for ferromagnetic material while the detection procedure is complicated and may cause pollution [6].…”

Section: Introductionmentioning

confidence: 99%

Physic perspective fusion of electromagnetic acoustic transducer and pulsed eddy current testing in non-destructive testing system

Guo

Gao

Tian

et al. 2020

Phil. Trans. R. Soc. A.

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Comprehensive non-destructive testing (NDT) for pipelines is a critical and challenging task. This paper proposes a novel physic perspective fusion NDT method of electromagnetic acoustic transducer (EMAT) and pulsed Eddy current testing (PECT) for detecting hybrid defects. This transceiver-integrated fusion sensor structure can simultaneously excite ultrasound and pulsed eddy current. Therefore, the generated ultrasound is applied to detect deep defects, while the eddy current detects surface defects. The theoretical derivation of EMAT and PECT fusion mechanism has been developed for analysis and interpretation of the results. In addition, numerical simulation on the detection of hybrid defects including surface defects with different width, depth and multiple bottom-thinning defects has been conducted. Experiments on both ferromagnetic and non-ferromagnetic material verify the feasibility of composite detection. Finally, tests have been validated on pipeline with weld defects, and the results show that the composite inspection method is capable of monitoring thickness variations and inspecting surface defects. This article is part of the theme issue ‘Advanced electromagnetic non-destructive evaluation and smart monitoring’.

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Coupling pulse eddy current sensor for deeper defects NDT

Cited by 61 publications

References 22 publications

Nondestructive Testing for Corrosion Evaluation of Metal under Coating

Nondestructive Testing for Corrosion Evaluation of Metal under Coating

Investigation of Signal Conditioning for Tx-Rx PEC Probe at High Lift-Off Using a Modified Maxwell’s Bridge

Physic perspective fusion of electromagnetic acoustic transducer and pulsed eddy current testing in non-destructive testing system

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