A frameless eddy current sensor for cryogenic displacement measurement

Wang, Peng; Zhi-bin, FU; Ding, Tianhuai

doi:10.1016/j.sna.2010.01.029

Cited by 23 publications

(12 citation statements)

References 12 publications

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“…For the excitation configuration showed in Fig. (10), because of "skin effect" theory, when AC current was applied between the inside conductor's two ends, the current will focus on conductor's out side [14][15][16], then can obtain spatial circumferential excitation. Important phenomenon "phase knot" is used for test and verification.…”

Section: Excitationmentioning

confidence: 99%

Research on High Resolution Stress Corrosion Crack Detection Based on Remote Field Eddy Current Non-Destructive Testing

Xu¹,

Jia²,

Zhang³

2015

TOMEJ

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Although remote field eddy current had achieved successive application in pipes and tubes non-destructive testing, the poor ability and sensitivity to axial crack such as stress corrosion crack prevented its further application. A novel high resolution remote field eddy current detection method which can be suitable for axial crack especially stress corrosion crack detection was proposed and verified by simulation and experiment. First of all, conventional detection ability of remote field eddy current for crack in different directions was researched with detail. Aside from this, applicability of orthogonal magnetic filed in remote field eddy current was analyzed and simulated by finite element method, and appropriate configuration using to generating orthogonal magnetic fields for tubular structure was discussed and verified. Thirdly, design of detection system including key parameters selection and detection coil mode were researched. At last, proposed high resolution detection system were verified experimentally using various type defects, such as parallel axial crack and real stress corrosion crack. From the above research, conclusions were drawn as followed: the detection ability and sensitivity of proposed remote field eddy current detection system could be improved significantly compared with conventional system, especially for axial crack which was not easily to detect, and real stress corrosion crack could be detected and evaluated successively.

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Section: Excitationmentioning

confidence: 99%

Research on High Resolution Stress Corrosion Crack Detection Based on Remote Field Eddy Current Non-Destructive Testing

Xu¹,

Jia²,

Zhang³

2015

TOMEJ

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“…Configuration 1 adds a coaxial cylindrical conductor inside a conventional solenoid, as shown in Figure 8a . When an AC current is applied between two ends of the cylindrical conductor, due to the skin effect, the current will be collected on the surface [ 18 , 19 ], and then the circumferential magnetic field will be obtained.…”

Section: Novel Sensor Designmentioning

confidence: 99%

A Novel High Sensitivity Sensor for Remote Field Eddy Current Non-Destructive Testing Based on Orthogonal Magnetic Field

Liu

Zhang

et al. 2014

Sensors

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Remote field eddy current is an effective non-destructive testing method for ferromagnetic tubular structures. In view of conventional sensors' disadvantages such as low signal-to-noise ratio and poor sensitivity to axial cracks, a novel high sensitivity sensor based on orthogonal magnetic field excitation is proposed. Firstly, through a three-dimensional finite element simulation, the remote field effect under orthogonal magnetic field excitation is determined, and an appropriate configuration which can generate an orthogonal magnetic field for a tubular structure is developed. Secondly, optimized selection of key parameters such as frequency, exciting currents and shielding modes is analyzed in detail, and different types of pick-up coils, including a new self-differential mode pick-up coil, are designed and analyzed. Lastly, the proposed sensor is verified experimentally by various types of defects manufactured on a section of a ferromagnetic tube. Experimental results show that the proposed novel sensor can largely improve the sensitivity of defect detection, especially for axial crack whose depth is less than 40% wall thickness, which are very difficult to detect and identify by conventional sensors. Another noteworthy advantage of the proposed sensor is that it has almost equal sensitivity to various types of defects, when a self-differential mode pick-up coil is adopted.

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“…Conventionally, an ECS is composed of an excitation and a reception component. High-frequency excitation induces eddy currents on or near the surface of the metal, and induces a strong secondary magnetic field [11,12]. Variations in displacement change the intensity of eddy currents and the corresponding magnetic field.…”

Section: Introductionmentioning

confidence: 99%

A Displacement Sensing Method Based on Permanent Magnet and Magnetic Flux Measurement

Zhang

Shi

Huang

et al. 2022

Sensors

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This paper proposes a displacement sensing method based on magnetic flux measurement. A bridge-structured magnetic circuit, formed by permanent magnets and two ferromagnetic cores, is designed and discussed. The analyses of the equivalent magnetic circuit and three-dimensional finite element simulations showed that the magnetic flux density changes linearly with the reciprocal of the sum of a constant and the displacement. A prototype sensor of the bridge structure is developed that consists of four permanent magnets as excitation, a Hall sensor as reception, and two ferromagnetic cores as the connection. Experiments have validated the feasibility of this method. The measured results show a good linearity between the sensor’s output and the reciprocal of the sum of a constant and the displacement, with a correlation coefficient greater than 0.9995 across different measurement ranges. Additionally, the measured results significantly indicate that the proposed sensor is compatible with different ferromagnetic materials with a worst-case error of less than 5%. The proposed sensor has the advantages of low cost and good linearity; however, the test object is limited to ferromagnetic materials.

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A frameless eddy current sensor for cryogenic displacement measurement

Cited by 23 publications

References 12 publications

Research on High Resolution Stress Corrosion Crack Detection Based on Remote Field Eddy Current Non-Destructive Testing

Research on High Resolution Stress Corrosion Crack Detection Based on Remote Field Eddy Current Non-Destructive Testing

A Novel High Sensitivity Sensor for Remote Field Eddy Current Non-Destructive Testing Based on Orthogonal Magnetic Field

A Displacement Sensing Method Based on Permanent Magnet and Magnetic Flux Measurement

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