Accurate evaluation of objects being inspected by the magnetic flux leakage testing (MFL) method relies on a good correlation between the signal characteristics and the discontinuities under actual test conditions. In practical MFL, imperfect shape and position of the products will lead to a changeable spatial location of the sensors and generate different signal characteristics even for the same discontinuity. In this paper, the signal characteristics of the widely used circular induction coil influenced by spatial location are investigated. First, based on magnetic dipole theory, the magnetic flux leakage distribution of a standard discontinuity is obtained. Second, based on Faraday’s law of electromagnetic induction, the signal response model of a circular induction coil at an arbitrary spatial location is built. Then, the influence of the coil spatial location on signal characteristics is analyzed by changing the coil spatial location. It is found that the spatial location influences the signal characteristics greatly, including the signal waveform and the amplitude, which should be taken into consideration in the sensor design and signal analysis. Lastly, MFL experiments are conducted to verify the signal characteristics of the circular induction coil, and the testing results are consistent with theoretical analysis.
Al-Naemi, F.I., J.P. Hall, and A.J. Moses, 2006, “FEM Modelling Tech-niques of Magnetic Flux Leakage-Type NDT for Ferromagnetic Plate Inspections,” Journal of Magnetism and Magnetic Materials, Vol. 304, No. 2, pp. e790–e793.
API, 2008, “Specification 6D/ISO 14313: Petroleum and Natural Gas Industries- Pipeline Transportation Systems – Pipeline Valves, Specifica-tion for Line Pipe,” American Petroleum Institute, Washington, DC, Technical Report 44.
Bray, D. E., and R. K. Stanley, 1966, Nondestructive Evaluation: A Tool in Design, Manufacturing and Service, CRC Press Inc., Boca Raton, Florida.
Carvalho, A.A., R.R. Silva, J.M.A. Rebello, and L.V.S. Sagrilo, 2010, “Pattern Recognition Techniques Applied to the Detection and Classifica-tion of Welding Defects by Magnetic Testing,” Research in Nondestructive Evaluation, Vol. 21, No. 2, pp. 91–111.
Cheng, W.Y., 2016, “Magnetic Flux Leakage Testing of Reverse Side Wall-Thinning by Using Very Low Strength Magnetization,” Journal of Nondestructive Evaluation, Vol. 35, No. 31, doi: 10.1007/s10921-016-0347-7.
Cui, W., H.-Y. Xing, M.-Z. Jiang, and J.-C. Leng, 2017, “Using a New Magnetic Flux Leakage Method to Detect Tank Bottom Weld Defects,” The Open Petroleum Engineering Journal, Vol. 10, pp. 73–81.
Dutta, S.M., F.H. Ghorbel, and R.K. Stanley, 2009, “Simulation and Analysis of 3-D Magnetic Flux Leakage,” IEEE Transactions on Magnetics, Vol. 45, No. 4, pp. 1966–1972.
Fernandes, B., J.D. Wade, D.K. Nims, and V.K. Devabhaktuni, 2012, “A New Magnetic Sensor Concept for Nondestructive Evaluation of Deterio-rated Prestressing Strand,” Research in Nondestructive Evaluation, Vol. 23, No. 1, pp. 46–68.
Kang, Y.H., J.B. Wu, and Y. H. Sun, 2012, “The Use of Magnetic Flux Leakage Testing Method and Apparatus for Steel Pipe,” Materials Evaluation, Vol. 70, No. 7, pp. 821–827.
Kashyap, S. K., G. Laxminarayna, S. Tewari, and A. Sinha, 2005, “Non-Destructive Testing of Steel Wire Ropes and Their Discard Criteria,” Proceedings of the 8th International Conference on Non-Destructive Testing in Engineering, Portorož, Slovenia, September 2005, pp. 1–3.
Katoh, M., N. Masumoto, K. Nishio, and T. Yamaguchi, 2003, “Modeling of the Yoke-Magnetization in MFL – Testing by Finite Elements,” NDT & E International, Vol. 36, No. 7, pp. 479–486.
Kreutzbruck, M., M. Pelkner, T. Erthner, and V. Reimund, 2013, “A6.3 -Automated Non-Destructive Testing of Roller Bearings Using GMR-Sensorarrays,” Proceedings SENSOR 2013, AMA Conferences 2013, Nürnberg, Germany, 14–16 May 2013, pp. 138–142.
Li, Y., J. Wilson, and G.Y. Tian, 2007, “Experiment and Simulation Study of 3D Magnetic Field Sensing for Magnetic Flux Leakage Defect Characteri-sation,” NDT & E International, Vol. 40, No. 2, pp. 179–184.
Ma, Y., R. He, and J. Chen, 2015, “A Method for Improving SNR of Drill Pipe Leakage Flux Testing Signals by Means of Magnetic Concentrating Effect,” IEEE Transactions on Magnetics, Vol. 51, No. 9, doi:10.1109/TMAG.2015.2427272.
Mandal, K., and D.L. Atherton, 1998, “A Study of Magnetic Flux-Leakage Signals,” Journal of Physics D: Applied Physics, Vol. 31, No. 22, pp. 3211–3217.
Mandache, C., and L. Clapham, 2003, “A Model for Magnetic Flux Leakage Signal Predictions,” Journal of Physics D: Applied Physics, Vol. 36, No. 20, pp. 2427–2431(5).
Park, G.S., and S.H. Park, 2004, “Analysis of the Velocity-Induced Eddy Current in MFL Type NDT,” IEEE Transactions on Magnetics, Vol. 40, No. 2, pp. 663–666.
Ramuhalli, P., L. Udpa, and S.S. Udpa, 2003, “Neural Network-Based Inversion Algorithms in Magnetic Flux Leakage Nondestructive Evalua-tion,” Journal of Applied Physics, Vol. 93, pp. 8274–8276.
Shcherbinin, V., and A. Pashagin, 1972, “Influence of the Extension of a Defect on the Magnitude of its Magnetic Field,” Defektoskopiya, Vol. 8, No. 4, pp. 84–78.
Shi, P. P., 2015, “Analytical Solutions of Magnetic Dipole Model for Leakage Magnetic Fields,” Nondestructive Testing, Vol. 37, No. 3, pp. 1–7.
Sun, Y. H., S. W. Liu, Z. J. Ye, S. Chen, and Q. Zhou, 2016, “A Defect Eval-uation Methodology Based on Multiple MFL Testing Signal Eigenvalues,” Research in Nondestructive Evaluation, Vol. 27, No. 1, pp. 1–25.
Tumanski, S., 2007, “Induction Coil Sensors—A Review,” Measurement Science and Technology, Vol. 18, No. 3, pp. R31.
Wang, P., Y. Gao, G.Y. Tian, and H. Wang, 2014, “Velocity Effect Analysis of Dynamic Magnetization in High Speed Magnetic Flux Leakage Inspec-tion,” NDT & E International, Vol. 64, pp. 7–12.
Wu, J., H. Fang, X. Huang, H. Xia, Y. Kang, and C. Tang, 2017, “An Online MFL Sensing Method for Steel Pipe Based on the Magnetic Guiding Effect,” Sensors, Vol. 17, No. 12, p. E2911.
Wu, J., H. Fang, L. Li, and Y. Kang, 2016, “The Signal Characteristics of Rectangular Induction Coil Affected by Sensor Arrangement and Scanning Direction in MFL Application,” International Journal of Applied Electromagnetics and Mechanics, Vol. 52, Nos. 3–4, pp. 1257–1265.
Wu, J., Y. Sun, B. Feng, and Y. Kang, 2017, “The Effect of Motion-Induced Eddy Current on Circumferential Magnetization in MFL Testing for a Steel Pipe,” IEEE Transactions on Magnetics, Vol. 53, No. 7, doi: 10.1109/TMAG.2017.2655483.
Wu, J., Y. Sun, Y. Kang, and Y. Yang, 2015, “Theoretical Analyses of MFL Signal Affected by Discontinuity Orientation and Sensor-Scanning Direc-tion,” IEEE Transactions on Magnetics, Vol. 51, No. 1, doi: 10.1109/TMAG.2014.2350460.
Xu, J., X. Wu, C. Cheng, and A. Ben, 2012, “A Magnetic Flux Leakage and Magnetostrictive Guided Wave Hybrid Transducer for Detecting Bridge Cables,” Sensors, Vol. 12, No. 1, pp. 518–533.
Zatsepin, N., and V. Shcherbinin, 1966, “Calculation of Magneto Static Field of Surface Defects. I. Field Topography of Defects Model,” Defek-toskopiya, Vol. 50, No. 5, pp. 50–59.
Zeng, Z., L. Xuan, Y. Sun, L. Udpa, and S. Udpa, 2004, “Probability of Detection Model for Gas Transmission Pipeline Inspection,” Research in Nondestructive Evaluation, Vol. 15, No. 3, pp. 99–110.
Zhang, D., M. Zhao, and Z. Zhou, 2012, “Quantitative Inspection of Wire Rope Discontinuities Using Magnetic Flux Leakage Imaging,” Materials Evaluation, Vol. 70, No. 7, pp. 872–878.
95 Page Views
0 PDF Downloads
0 Facebook Shares