scholarly journals The metallic sphere in a uniform ac magnetic field: A simple and precise experiment for exploring eddy currents and non-destructive testing

2018 ◽  
Vol 86 (6) ◽  
pp. 430-438 ◽  
Author(s):  
Michael L. Honke ◽  
Christopher P. Bidinosti
Keyword(s):  
Magnetic Field ◽  
Eddy Currents ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Ac Magnetic Field ◽  
Precise Experiment ◽  
Non Destructive

Electromagnetic Effect of Eddy Currents in Composites with Conductive Components: Magnetic Field Strengthening and its Simple Analytical Estimation

2018 ◽  
Vol 284 ◽  
pp. 37-42 ◽  
Author(s):  
R.R. Sattarov ◽  
T.A. Volkova ◽  
I.Z. Gubaydullin
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Compatibility ◽  
Eddy Currents ◽  
Electromagnetic Effect ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Compatibility Analysis ◽  
Dynamic Materials ◽  
Analytical Estimation ◽  
Non Destructive

Composites and dynamic materials that include conductive components are becoming a suitable choice in different applications. The eddy currents are generated when the conductive components are placed in alternating magnetic field. The eddy currents decrease the primary field and this effect has been well studied and it is used for electromagnetic shielding. Besides, the magnetic field increases in small space near edges of the conductive components. While this effect of magnetic field strengthening is known, it is rarely examined. We will introduce a simple model that can be appropriate for the conductive components in form of long thin sheets. We analytically analyze the model and obtain expressions that give upper bounds for increasing of the net magnetic field. The electromagnetic effect of strengthening should be taken into account when considering an application of the composites. The results are useful for electromagnetic compatibility analysis, non-destructive testing and monitoring of composite and dynamic materials with conductive components.

Technical Note: Detection of delamination in tyres using eddy currents

1997 ◽  
Vol 211 (1) ◽  
pp. 79-82 ◽  
Author(s):  
X. E. Gros
Keyword(s):  
Eddy Currents ◽  
Structural Integrity ◽  
Low Cost ◽  
Technical Note ◽  
Quality And Safety ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Safety Standards ◽  
Current Testing ◽  
Non Destructive

Non-destructive testing (NDT) is a useful tool to assess the structural integrity of components in order to maintain quality and safety standards. A low-cost electromagnetic technique based on eddy currents induced into a material appeared promising for the inspection of composite materials. Experiments were carried out in order to assess the potential of eddy currents in detecting delamination in rubber tyres. Infrared thermography was used to verify inspection results achieved with eddy currents. Non-destructive examination results are presented in this paper; these confirm that eddy current testing is an economically viable alternative for the inspection of steel reinforced truck tyres.

Characterization of Magnetic Field in Crack Propagation Stage and Application to Non-Destructive Evaluation

2020 ◽  
Author(s):  
Sheng Bao ◽  
Zhengye Zhao ◽  
Qiang Luo ◽  
Jian Yang
Keyword(s):  
Magnetic Field ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Magnetic Measurement ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive ◽  
The Magnetic Field

Abstract Monitoring of fatigue crack propagation is very important in industrial fields. Stress-induced magnetic measurement is a newly developed non-destructive testing technique which can detect early failure of ferromagnetic materials in service. A lot of experiments demonstrate that magnetic measurement is more sensitive compared with other non-destructive testing technologies. In order to explore the correlation between crack propagation and magnetic hysteresis under cyclic stress in X70 pipeline steel, a series of stress-controlled tests were carried out and the changes in magnetic field around cracks during their propagation process were observed throughout the tension-tension fatigue tests. The variations of magnetic field and stress intensity factor K in the crack propagation stage were studied. The results obtained allowed the division of the magnetic behavior of the investigated steels into three stages corresponding to three distinct crack propagation stages. It was found that the magnetic field varies with crack propagation, and the stress intensity factor K increased with the increase of loading cycles. A strong correlation between the variation of the magnetic field and stress intensity factor was recognized, regardless of the loading conditions, maximum load or stress ratio. The results suggest that non-destructive evaluation of fatigue cracks would be possible using this relationship.

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