Sensor-tilt invariance analysis for eddy current signals

Yang, Guang; Zeng, Zhiwei; Deng, Yiming; Liu, X.; Удпа, Лалита; Dib, Gerges

doi:10.1016/j.ndteint.2012.08.006

Cited by 10 publications

(5 citation statements)

References 24 publications

(44 reference statements)

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“…However, the use of permanent magnets to generate the magnetic field limits their depth of defect detection. Yang et al [ 98 ] used a GMR sensor to investigate the quality of aeronautical structures. The focus of their study was the defects under the riveted headings used to connect the airplane wing structure.…”

Section: Application Of Gmr Sensors In Hybrid Eddy Current Testingmentioning

confidence: 99%

Giant Magnetoresistance Sensors: A Review on Structures and Non-Destructive Eddy Current Testing Applications

Rifai

Abdalla

Ali

et al. 2016

Sensors

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Non-destructive eddy current testing (ECT) is widely used to examine structural defects in ferromagnetic pipe in the oil and gas industry. Implementation of giant magnetoresistance (GMR) sensors as magnetic field sensors to detect the changes of magnetic field continuity have increased the sensitivity of eddy current techniques in detecting the material defect profile. However, not many researchers have described in detail the structure and issues of GMR sensors and their application in eddy current techniques for nondestructive testing. This paper will describe the implementation of GMR sensors in non-destructive testing eddy current testing. The first part of this paper will describe the structure and principles of GMR sensors. The second part outlines the principles and types of eddy current testing probe that have been studied and developed by previous researchers. The influence of various parameters on the GMR measurement and a factor affecting in eddy current testing will be described in detail in the third part of this paper. Finally, this paper will discuss the limitations of coil probe and compensation techniques that researchers have applied in eddy current testing probes. A comprehensive review of previous studies on the application of GMR sensors in non-destructive eddy current testing also be given at the end of this paper.

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Section: Application Of Gmr Sensors In Hybrid Eddy Current Testingmentioning

confidence: 99%

Giant Magnetoresistance Sensors: A Review on Structures and Non-Destructive Eddy Current Testing Applications

Rifai

Abdalla

Ali

et al. 2016

Sensors

View full text Add to dashboard Cite

show abstract

“…[5] However, a probe sometimes tilts due to surface deformation [3] or poor surface treatment. [6] Basically, eddy current signals are fairly sensitive to probe inclination. The unwanted signal change due to probe tilt is reported to be one of the major obstacles for effective ECT.…”

Section: Introductionmentioning

confidence: 99%

“…The unwanted signal change due to probe tilt is reported to be one of the major obstacles for effective ECT. [6,7] To reduce it, there is a strong demand for powerful, accurate, efficient, and cost-effective tools to investigate the physics.…”

Section: Introductionmentioning

confidence: 99%

Analytical model of tilted driver–pickup coils for eddy current nondestructive evaluation

Cao

Fan

et al. 2018

Chinese Phys. B

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A driver-pickup probe possesses better sensitivity and flexibility due to individual optimization of a coil. It is frequently observed in an eddy current (EC) array probe. In this work, a tilted non-coaxial driver-pickup probe above a multilayered conducting plate is analytically modeled with spatial transformation for eddy current nondestructive evaluation. Basically, the core of the formulation is to obtain the projection of magnetic vector potential (MVP) from the driver coil onto the vector along the tilted pickup coil, which is divided into two key steps. The first step is to make a projection of MVP along the pickup coil onto a horizontal plane, and the second one is to build the relationship between the projected MVP and the MVP along the driver coil. Afterwards, an analytical model for the case of a layered plate is established with the reflection and transmission theory of electromagnetic fields. The calculated values from the resulting model indicate good agreement with those from the finite element model (FEM) and experiments, which validates the developed analytical model.

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“…The EC-GMR technique, using a single linear excitation coil, has been presented to detect fatigue cracks around fasteners in multilayer structures [ 9 , 10 , 11 ], where the induced currents are primarily generated along one direction. A linear array of GMR sensors located on the symmetry plane of the coil picks up the normal component (

) of a magnetic field associated with eddy currents.…”

Section: Introductionmentioning

confidence: 99%

Optimization and Validation of Rotating Current Excitation with GMR Array Sensors for Riveted Structures Inspection

Удпа

2016

Sensors

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In eddy current non-destructive testing of a multi-layered riveted structure, rotating current excitation, generated by orthogonal coils, is advantageous in providing sensitivity to defects of all orientations. However, when used with linear array sensors, the exciting magnetic flux density (Bx) of the orthogonal coils is not uniform over the sensor region, resulting in an output signal magnitude that depends on the relative location of the defect to the sensor array. In this paper, the rotating excitation coil is optimized to achieve a uniform Bx field in the sensor array area and minimize the probe size. The current density distribution of the coil is optimized using the polynomial approximation method. A non-uniform coil design is derived from the optimized current density distribution. Simulation results, using both an optimized coil and a conventional coil, are generated using the finite element method (FEM) model. The signal magnitude for an optimized coil is seen to be more robust with respect to offset of defects from the coil center. A novel multilayer coil structure, fabricated on a multi-layer printed circuit board, is used to build the optimized coil. A prototype probe with the optimized coil and 32 giant magnetoresistive (GMR) sensors is built and tested on a two-layer riveted aluminum sample. Experimental results show that the optimized probe has better defect detection capability compared with a conventional non-optimized coil.

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Sensor-tilt invariance analysis for eddy current signals

Cited by 10 publications

References 24 publications

Giant Magnetoresistance Sensors: A Review on Structures and Non-Destructive Eddy Current Testing Applications

Giant Magnetoresistance Sensors: A Review on Structures and Non-Destructive Eddy Current Testing Applications

Analytical model of tilted driver–pickup coils for eddy current nondestructive evaluation

Optimization and Validation of Rotating Current Excitation with GMR Array Sensors for Riveted Structures Inspection

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