scholarly journals Fractional derivative resolution of the anomalous magnetic field diffusion through a ferromagnetic steel rod: Application to eddy current testing

2021 ◽  
pp. 105953
Author(s):  
B. Ducharne ◽  
B. Zhang ◽  
G. Sebald
Keyword(s):  
Magnetic Field ◽  
Fractional Derivative ◽  
Eddy Current ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Anomalous Magnetic Field ◽  
Field Diffusion ◽  
Ferromagnetic Steel

Quantitative Research on Cracks in Pipe Based on Magnetic Field Response Method of Eddy Current Testing

2021 ◽  
Vol 36 (1) ◽  
pp. 99-107
Author(s):  
Feng Jiang ◽  
Shulin Liu ◽  
Li Tao
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Quantitative Research ◽  
Three Dimensional ◽  
Impedance Analysis ◽  
Eddy Current Testing ◽  
Element Analysis ◽  
Defect Parameter ◽  
Current Testing ◽  
The Magnetic Field

The quantitative evaluation of defects in eddy current testing is of great significance. Impedance analysis, as a traditional method, is adopted to determine defects in the conductor, however, it is not able to depict the shape, size and location of defects quantitatively. In order to obtain more obvious characteristic quantities and improve the ability of eddy current testing to detect defects, the study of cracks in metal pipes is carried out by utilizing the analysis method of three-dimensional magnetic field in present paper. The magnetic field components in the space near the crack are calculated numerically by using finite element analysis. The simulation results confirm that the monitoring of the crack change can be achieved by measuring the magnetic field at the arrangement positions. Besides, the quantitative relationships between the shape, length of the crack and the magnetic field components around the metal pipe are obtained. The results show that the axial and radial magnetic induction intensities are affected more significantly by the cross-section area of the crack. Bz demonstrates obvious advantages in analyzing quantitatively crack circumference length. Therefore, the response signal in the three-dimensional direction of the magnetic field gets to intuitively reflect the change of the defect parameter, which proves the effectiveness and practicability of this method.

scholarly journals Construct Coil Probe Using GMR Sensor for Eddy Current Testing

2018 ◽  
Vol 225 ◽  
pp. 02021 ◽  
Author(s):  
Moneer A Faraj ◽  
Ahmed N Abdalla ◽  
Fahmi Bin Samsuri ◽  
Damhuji Rifai ◽  
Kharudin Ali
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Ferromagnetic Material ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Calibration Block ◽  
Gmr Sensor ◽  
Non Destructive ◽  
Magneto Resistance ◽  
Detection Medium

Eddy current testing is a widely applied non-destructive technique in different sections of industries. Nowadays eddy current testing is an accurate, widely used and well-understood inspection technique, particularly in the aircraft and nuclear industries. The main purpose of this paper is to construct an eddy current probe by using transmission coil and using a Giant Magneto resistance (GMR) sensor for detection medium. This probe only use a magnetic field to operational in detection of flaws. A transmission coil is an object made from a material that is magnetized and creates its own persistent magnetic field. A GMR-coil probe has been used to inspect two different material of calibration block. Experimental results obtained by scanning A GMR-coil probe over Brass calibration block has 10 slots with different depth from 0.5mm to 5mm and mild steel has 8 slots with different depth from 0.5mm to 4mm are presented. The result prove that GMR-coil probe that operated using a magnetic field and sensor more effective on ferromagnetic material.

Remote Field Eddy Current Testing for SG Inspection of Fast Reactor

2010 ◽  
Author(s):  
Noriyasu Kobayashi ◽  
Souichi Ueno ◽  
Satoshi Nagai ◽  
Makoto Ochiai ◽  
Noboru Jimbo
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Fast Reactor ◽  
Eddy Current ◽  
Magnetic Field Intensity ◽  
High Sensitivity ◽  
Eddy Current Testing ◽  
Wire Mesh ◽  
Current Testing ◽  
Horizontal Type

We confirmed defect detection performance of a remote field eddy current testing (RFECT) in order to inspect a helical-coil-type double wall tube steam generator (DWTSG) with a wire mesh layer for the new-type small fast reactor 4S (Supersafe, Small and Simple). As high sensitivity techniques, to increase an indirect magnetic field intensity, we focused attention on increasing a direct magnetic field intensity in the vicinity of an exciter coil by the use of an exciter coil with a magnetic material (flux guide). We adopted horizontal type multiple detector coils with flux guides arrayed circumferentially to enhance sensitivity of radial direction. According to the experimental results, the indirect magnetic field intensity (the voltage of detector coil in the region of indirect magnetic field) increased more than 100 times by the application of the exciter and detector coils with flux guides. Finally, we detected the pinhole defect of 1 mm in diameter and 20% of outer tube thickness in depth over the wire mesh layer by the adoption of the flux guides and horizontal type multiple detector coils. And we confirmed that the RFECT probe is also useful to detect the thinning defects.

Evaluation of circumferential cracks in metal tubes based on a magnetic field response model of eddy current testing

2020 ◽  
Vol 62 (2) ◽  
pp. 91-97
Author(s):  
Feng Jiang ◽  
Shulin Liu ◽  
Shaojie Xin ◽  
Hongli Zhang
Keyword(s):  
Magnetic Field ◽  
Theoretical Model ◽  
Analytical Model ◽  
Eddy Current ◽  
Eddy Current Testing ◽  
Metal Tube ◽  
Destructive Testing ◽  
Current Testing ◽  
Field Response ◽  
The Magnetic Field

According to the characteristics of circumferential cracks on the inner surface of metal tubes, a magnetic field response method has been proposed and a mathematical analytical model for detecting the circumferential crack has also been established. The theoretical model, based on the magnetic field response, could be expressed as a series sum of trigonometric and Bessel functions. The relationship between the distribution of the magnetic field in the inner region of the metal tube and the geometrical size of the cracks is also analysed. The results show that the analytical model can effectively explain and analyse the variation of the surrounding magnetic field caused by the crack. The characteristic parameters of the crack, Br and Bz , which are extracted from the magnetic field, have certain quantitative recognition abilities. In addition, an increase in the thickness of the metal tube causes a larger range of magnetic field variations and is considered to be disadvantageous for detecting a change in the magnetic induction intensity that is a result of the crack. A theoretical model and research results contribute to the development of eddy current testing and improve the accuracy of the non-destructive testing and evaluation of metal tubes.

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