International Journal of Applied Electromagnetics and Mechanics - Volume 39, issue 1-4

Authors: Nguyen, T.A. | Joubert, P.-Y. | Lefebvre, S. | Chaplier, G.

Article Type: Research Article

Abstract: The paper reports on the estimation of the distribution of currents flowing in a metalized part, starting from two-dimensional maps of the magnetic field induced above the part, with the monitoring of power semiconductor dies in view. The estimation is obtained from the measured data by inverting a mesh-free modeling of the induced magnetic field. First inversion results of experimental data are presented and discussed.

Keywords: Current distribution, Hall effect sensor, power semiconductor modules monitoring, mesh free modeling method, inverse problem

DOI: 10.3233/JAE-2012-1455

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 151-156, 2012

Authors: Reinbacher-Köstinger, Alice | Magele and, Christian | Renhart, Werner

Article Type: Research Article

Abstract: The identification of a conductive object known in shape but hidden by low- or non-conductive material is a special application of non-destructive eddy current testing. To find the positioning and orientation parameters of an object from the magnetic flux densities measured in a distance of several centimeters, a non-linear inverse problem has to be solved. This can be done by deterministic as well as stochastic optimization methods in principle. In order to fulfill all demands on …the identification process, that are high accuracy, reliability and low computation time, a combination of a deterministic and a stochastic method is useful and was therefore applied to the problem at hand. It is shown that the computation time can be decreased enormously applying a hybrid method while the required accuracy and reliability hold. Show more

Keywords: Evolution Strategy, Identification, Hidden Object, ECT, GMR

DOI: 10.3233/JAE-2012-1456

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 157-166, 2012

Authors: Chlewicki, Wojciech | Baniukiewicz, Piotr | Chady, Tomasz | Brykalski, Andrzej

Article Type: Research Article

Abstract: Digital radiography is a very useful tool in nondestructive evaluation. However, single radiographic projection contains information about the potential defect only in two dimensions. Thus, the defects may be overlapped or placed parallel to the X-ray beam. We present how a simple, low-cost extension of an existing radiographic system may increase its capability so that it is possible to localize objects in three dimensions. The presented methodology is based on approximate three-dimensional reconstruction …from few projections and depth identification procedure. The proposed method also increases detectability of the potential defect. Show more

Keywords: Digital radiography, image reconstruction, defect detection

DOI: 10.3233/JAE-2012-1457

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 167-173, 2012

Authors: Wołszyn, Mirosław

Article Type: Research Article

Abstract: The new non-iterative method of determining the dipole moment and location is presented in this paper. The algorithm of an object's localization and identification was achieved by using numerical calculations and approximation method. The arbitrary shapes of an object were assumed in the identification algorithm – axially symmetric spheroid (a prolate and an oblate). Several examples of localization and identification of an object's models were presented. Magnetic field of each object's model was calculated in …Opera 3D program. An example of determining a missile's location and identification was presented in this paper. Show more

Keywords: Magnetic field, localization, identification, ferrous object

DOI: 10.3233/JAE-2012-1458

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 175-182, 2012

Authors: Jakubiuk, Kazimierz | Zimny, Paweł | Wołszyn, Mirosłw

Article Type: Research Article

Abstract: Ships made of ferromagnetic metals interfere with Earth's magnetic field in their surrounding. The disturbance of the magnetic field makes possible localization and even identification of the ship, which could determine a threat to the ship. The measurement of the magnetic field around the ship enables to determine its magnetic signature. The paper presents a multidipoles model of the ship magnetic field, which allows to determine parameters of the ship magnetic signature.

Keywords: Magnetic field, ship, signature

DOI: 10.3233/JAE-2012-1459

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 183-188, 2012

Authors: Desideri, Daniele | Maschio, Alvise

Article Type: Research Article

Abstract: A new version of coaxial transmission line sample holder with continuous conductor for measurement of shielding effectiveness of planar films has been developed. The inner conductor of the sample holder is divided in two parts; at one end of the two parts an internal and an external straight thread respectively have been realized. The connection of the inner conductor is done by screwing the two parts, pressing the film and its substrate between two flat annular …surfaces. The contact is simple, reliable and effective. Contact resistance value of the order of milliohm has been obtained with a copper film deposited on PEEK substrate. With the deposited copper film, shielding effectiveness measurements in the frequency range 10 kHz–300 MHz have been done and are reported. Show more

Keywords: Planar film, sample holder, shielding effectiveness

DOI: 10.3233/JAE-2012-1460

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 189-194, 2012

Authors: Wu, Xinjun | Yuan, Jianming | Ben, Anran

Article Type: Research Article

Abstract: It is important to inspect bridge cables to insure the safety of the bridge, especially to test its loss of metallic cross-sectional area (LMA). A novel magnetic testing method for the LMA that the magnetic energy directly imposes on the bridge cable is proposed, which has advantages over the magnetic flux measurement used by traditional main-flux and return-flux methods. Its equivalent magnetic circuit is obtained, too. Furthermore, according to the magnetic Kirchhoff's Law and Taylor expansion …series, the theoretic model is obtained by ignoring the higher order and used to analyse the proposed magnetic testing method. Finally, it is verified experimentally and shown good resolution. Show more

Keywords: Magnetic testing, bridge cable, loss of metallic cross-sectional area

DOI: 10.3233/JAE-2012-1461

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 195-201, 2012

Authors: Xie, Shejuan | Chen, Zhenmao | Wang, Li | Takagi, Toshiyuki | Uchimoto, Tetsuya

Article Type: Research Article

Abstract: In this paper, an inversion algorithm has been proposed and validated, based on a fast simulator of pulsed eddy current testing (PECT) signals and a deterministic optimization strategy, for the profile reconstruction of wall thinning in pipes of nuclear power plants. Local wall thinning is modelled as a group of planar defects with different length and depth, reconstructed from two-dimensional PECT signals. Through inverse analysis of simulated signals and signals with random noise, the efficiency and …the robustness of the proposed algorithm have been demonstrated. Show more

Keywords: Wall thinning, pulsed ECT, QNDT, inversion problem, conjugate gradient

DOI: 10.3233/JAE-2012-1462

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 203-211, 2012

Authors: Xu, Zhiyuan | Wu, Xinjun | Huang, Chen | Ke, Hai

Article Type: Research Article

Abstract: In pulsed eddy current (PEC) testing, excitation signal parameters are of great importance for the probe detectability. Square-wave current excitation with linear ramp edges used in measuring steel-plate thickness is studied in this work. Based on spectrum analysis, simulation and experimental study, the influences of the duty cycle and edge transition time on response signals are analyzed. Results show that for thin specimens the duty cycle can be decreased properly but the edge time should be …as small as possible, and for thick specimens the duty cycle should be close to 50% while the edge time can be increased properly. This study can provide a reference for PEC signal interpretation and optimization of excitation parameters. Show more

Keywords: Pulsed eddy current (PEC), excitation parameters, ferromagnetic material

DOI: 10.3233/JAE-2012-1463

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 213-219, 2012

Authors: Li, Hongmei | Wang, Li | Li, Yong | Zhang, Dongli | Chen, Zhenmao

Article Type: Research Article

Abstract: The phenomenon of damage-induced magnetization possesses good application prospects in nondestructive testing and material evaluation purpose, once the relationship between the mechanical damage and the induced magnetization can be quantitatively established. As the magnetization can not be measured directly, it is vital to reconstruct the distribution of the magnetization within the materials from the measured magnetic field signals in order to find the correlation. In this paper, an approach has been studied to …realize the reconstruction of damage-induced magnetization in a flat plate from the magnetic field signals measured nearby the plate. A deterministic optimization scheme of the steepest descent method has been developed for the inversion in addition with a strategy dealing with the border-effect. Reconstructions with both simulated and measured signals verified the validity and efficiency of the proposed approach. Show more

Keywords: Magnetization reconstruction, mechanical damage, damage-induced magnetization, border-effect

DOI: 10.3233/JAE-2012-1464

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 221-227, 2012