An external through type RA-EMAT for steel pipe inspection

Tu, Jun; Zhong, Zhiwu; Song, Xiaochun; Zhang, Xu; Deng, Zhiyang; Liu, Mengran

doi:10.1016/j.sna.2021.113053

Cited by 19 publications

(4 citation statements)

References 13 publications

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“…Eddy currents can also be generated using spiral coil [104], multi-section coil [105], and meander coil [106,107]. The advantage of the spiral coil is its ability to generate an omnidirectional guided wave so that a defect within a pipeline can be imaged using two rings of the EMAT array.…”

Section: Lorentz-force-based Emat Arraymentioning

confidence: 99%

“…Cong et al [111] combined rectangular shape magnets and a multi-section coil to trigger longitudinal guided wave signals of different frequencies. Tu et al [105] used cylindrical permanent magnets with a multi-section coil to excite a fundamental torsional guided wave. In two EMATs, the multi-section coil was fully wrapped around a hollow structure, which can only be used to trigger an axisymmetric guided wave mode.…”

Section: Lorentz-force-based Emat Arraymentioning

confidence: 99%

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A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

Fang

2023

Smart Mater. Struct.

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An axisymmetric guided wave mode is excited independently within a circular tube structure to reduce the complexity of signal interpretation through the prevention of unwanted wave polarisations and reflections. However, it is difficult to use the axisymmetric guided wave to determine the circumferential position and coverage of a defect within the circular tube structure. Non-axisymmetric guided waves can be used to mitigate the limitation of the axisymmetric guided wave through the adoption of a partially covered transducer design and analysis of the propagation characteristics. The partial excitation of non-axisymmetric guided waves can facilitate the arrangement of a transducer during defect detection. This paper reviews state-of-the-art research on non-axisymmetric guided waves for determining the axial positions, circumferential positions, and circumferential lengths of defects. First, the fundamental analysis of a specific non-axisymmetric guided wave mode based on the normal mode expansion method and beam directivity analysis method reveals that the propagation characteristics of the wave mode are closely related to the working principle and configuration of the corresponding transducer. Then, the advantages and disadvantages of the different types of transducers and transducer arrays for the excitation of non-axisymmetric guided waves are introduced and discussed. Finally, the current defect detection methods based on non-axisymmetric guided waves are discussed and summarised. This review can promote the application of non-axisymmetric guided waves in defect detection.

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Section: Lorentz-force-based Emat Arraymentioning

confidence: 99%

Section: Lorentz-force-based Emat Arraymentioning

confidence: 99%

A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

Fang

2023

Smart Mater. Struct.

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“…To ensure the stability and durability of the pipeline, supporting frames are set at a certain distance periodically. The corrosion detection of the support is space-sealed, and the effective detection range of common portable EMAT is limited, making it difficult to detect the point-to-point ultrasonic thickness measurement [ 15 ]. If the corroded pipeline is lifted from the support for routine detection, it is not only time-consuming and laborious, but also dangerous because of leakage.…”

Section: Introductionmentioning

confidence: 99%

Research on Crossing-Pipe Support Structure Defect Detection of EMAT-Excited CSH Wave

Zhou

Yue

2023

Sensors

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A circumferential shear horizontal (CSH) guide wave-detection method using a periodic permanent magnet electromagnetic acoustic transducer (PPM EMAT) was proposed to solve the defect detection located at the inside of the pipe welded by supporting structures. Firstly, a low-frequency CSH0 mode was selected to establish a three-dimensional equivalent model for the defect detection to cross the pipe support, and the ability of the CSH0 guided wave to propagate through the support and weld structure was analyzed. Then, an experiment was used for the further exploration of the influence of different sizes and types of defects on detection after using the support, as well as the ability of detection mechanism to cross different pipe structures. The results show that both the experiment and the simulation received a good detection signal at 3 mm crack defects, which proves that the method can detect the defects by crossing the welded supporting structure. At the same time, the support structure shows a greater impact on the detection of small defects than the welded structure. The research in this paper can provide ideas for guide wave detection across the support structure in the future.

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“…The MFL testing method uses magnetic field perturbations caused by defects, which are affected by the "magnetic shielding effect" of the pipe wall, and its detection sensitivity gradually decreases with the increase in pipe wall thickness [17][18][19][20][21][22][23]. Electromagnetic acoustic transducers (EMATs) are suitable for detecting wall-thinning defects, but they are limited by a low efficiency of energy transfer [24,25]. TTBT detects leaks in pipelines through pressure changes and offers high sensitivity, but it is susceptible to environmental changes such as temperature changes and changes in the medium inside the pipeline [26,27].…”

Section: Introductionmentioning

confidence: 99%

Magnetic Permeability Perturbation Testing for Internal Axial Cracks in Small-Diameter Thick-Walled Steel Pipes

Zhao

Deng

et al. 2023

Applied Sciences

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Special geometric features and complex working environments render the internal defects of small-diameter thick-walled steel pipes “easy to expand, difficult to detect”. In this paper, a magnetic permeability perturbation testing (MPPT) method is proposed to assess the internal axial cracks of small-diameter thick-walled steel pipes. The mechanism of the MPPT method and its corresponding probe and magnetizer are introduced, and its feasibility is verified through a series of simulations and experiments. Experiments conducted using different sizes of small-diameter thick-walled pipes show that this method offers good performance with respect to the detection of internal axial cracks. Additionally, both diameter and wall thickness significantly affect the MPPT signal. To a certain extent, a greater wall thickness or a smaller diameter brings about a weaker signal. This method does not benefit from the lift-off effect, nor is it limited by the skin effect, which has great practical value as a supplement to the evaluation of thick-walled steel pipes.

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An external through type RA-EMAT for steel pipe inspection

Cited by 19 publications

References 13 publications

A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

A review of non-axisymmetric guided waves and their corresponding transducers for defect detection in circular tube structures

Research on Crossing-Pipe Support Structure Defect Detection of EMAT-Excited CSH Wave

Magnetic Permeability Perturbation Testing for Internal Axial Cracks in Small-Diameter Thick-Walled Steel Pipes

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