International Journal of Applied Electromagnetics and Mechanics - Volume 52, issue 3-4

Authors: Kim, Jungmin | Kim, Sejin | Le, Minhhuy | Lee, Jinyi | Park, Jongwoon

Article Type: Research Article

Abstract: A method for inspecting far-side fatigue cracks is proposed. These cracks occur in the spot-welding components of a heat-resistant alloy, used in aircraft engine components. For measurement without contact, an electromagnetic field is applied to the object. The distortion of the field owing to far-side fatigue cracks in the spot-welding area is measured with a linearly integrated giant-magneto resistance sensor array. Artificial far-side cracks can be detected where there is a slit-type crack around the spot-welding area. A probability of detection (POD) is used to analyze the detection performance of the inspection system. Crack with lengths of 3.699 mm and …4.647 mm were inspected with 90% POD and 90/95 POD with confidence bound, respectively. Show more

Keywords: Fatigue crack, inconel, magnetic camera, eddy current, sensor array, imaging, heat-resistant crack

DOI: 10.3233/JAE-162146

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1193-1199, 2016

Authors: Aoki, Fumiko | Kanda, Kosuke | Sugiura, Toshihiko

Article Type: Research Article

Abstract: Guided waves can propagate along waveguides with low attenuation. Therefore, guided waves are expected to be used for non-destructive testing especially of cylindrical structures such as wire-ropes. However, as guided waves propagate over longer distance, their attenuation cannot be neglected, though quantitative measurement of attenuation of cylindrical guided waves has not yet been given enough. Thus, we conducted theoretical analysis and experiment of wave attenuation. In theoretical analysis, we derived dispersion curves including effects of material attenuation in order to obtain frequency-dependent attenuation coefficients. In experiment, we transmitted and received guided waves by electromagnetic acoustic transducers (EMATs) in order to …measure attenuation of guided waves. By comparing the experimental results with the theoretical ones, we showed that the experimental results of wave attenuation increased with frequency just as the theoretical ones, though the formers were larger than the latters. Show more

Keywords: Cylindrical guided waves, EMATs, attenuation

DOI: 10.3233/JAE-162133

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1201-1206, 2016

Authors: Midorikawa, Yoichi | Akita, Masanori

Article Type: Research Article

Abstract: This paper improves a pattern recognition method for the signals under the noisy environment using method of emphasizing wavelet coefficients for reference clean signal data. If the data is polluted with noise, these signal pattern recognitions are extremely difficult problem. To analyze noise problem, people in general have used the fourier analysis. But the fourier analysis reveals only the frequency information. And the general noise filters reduce specific frequency band contained both noise and signal. It is difficult to eliminate only noise component from a signal containing noise signal. To overcome this difficulty, we applied the wavelet analysis. In this …paper, we improve the noisy signal pattern recognition by bringing it close to reference data and noisy input data by modifying the spectrum by using the wavelet transform for reference clean signal data. As a result, noisy signal pattern recognition rate is improved by this method. Show more

Keywords: Signal pattern recognition, noise, wavelet transform

DOI: 10.3233/JAE-162103

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1207-1212, 2016

Authors: Terashima, Kenichi | Ishiwata, Makoto | Suzuki, Kenji | Yamaguchi, Katsuhiko | Uchimoto, Tetsuya | Takagi, Toshiyuki

Article Type: Research Article

Abstract: A visualization method is proposed for detecting of residual stress in stainless steels using a magnetic domain scope combined with μ -MOKE measurement system. Grains and local residual stress places such as Lüders band on metal surfaces are clearly observed by this method. Moreover, different magnetic hysteresis curves were measured for each grain. A Monte Carlo simulation was performed for the analysis of the observation results. As a result, this method has possibility of a new magnetic non-destructive evaluation for fatigue of Austenitic stainless steels.

Keywords: Visualization method, magnetic domain, Austenitic stainless steels, non-destructive evaluation, Monte Carlo simulation

DOI: 10.3233/JAE-162055

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1213-1219, 2016

Authors: Sasai, Shiho | Nakamoto, Hiroyuki | Kobayashi, Futoshi | Kojima, Fumio

Article Type: Research Article

Abstract: Tactile sensors are required in various areas such as robotics, human interfaces. Since sensing elements and wiring space are limited, it is important that a few sensing elements cover a large area. In this study, a tactile sensor which comprises of an elastic layer and a substrate layer is proposed. This sensor has some magnets and giant magnetoresistance effect elements (GMR elements) as sensor elements. The tactile sensor estimates a location and depth of a touch based on the output voltages of GMR elements. The estimate equation is determined by the genetic programming. The effectiveness of the tactile sensor is …confirmed through laboratory experiments. Show more

Keywords: Tactile sensor, GMR, GP, multiple regression analysis

DOI: 10.3233/JAE-162090

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1221-1229, 2016

Authors: Horai, Satoru | Hirata, Katsuhiro | Niguchi, Noboru

Article Type: Research Article

Abstract: In Japan, deteriorated water pipes are increasing more and more now. Therefore, the setting of the priority to update these pipes effectively is required. As a solution of this problem, we proposed a new sensor using the principle of SLOFEC [1] and the structure of a focusing eddy current sensor [2]. In this paper, we verify the performances of the proposed sensor by 3D-FEM analysis. The effectiveness of the proposed sensor is also verified through measurements on a prototype.

Keywords: Water pipe, SLOFEC, eddy current sensor, finite element analysis

DOI: 10.3233/JAE-162099

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1231-1236, 2016

Authors: Chan, Poh Kam | Oikawa, Shun-ichi | Kosaka, Wataru

Article Type: Research Article

Abstract: The two-dimensional time-dependent Schrödinger equation, for a magnetized proton in the presence of a fixed field particle and of a uniform magnetic field is numerically solved. In the relatively high-speed case, the fast-speed proton has the similar behaviors to those of classical ones. However, in the extension of time, the relatively high-speed case shows similar behavior to the low-speed case: the cyclotron radii both in mechanical momentum and position are appreciably decreasing with time. However, the kinetic energy and the potential energy do not show appreciable changes. This is because of the increasing variances, i.e. uncertainty, both in momentum and …position. The increment in variance of momentum corresponds to the decrement in the magnitude of mechanical momentum in a classical sense: Part of energy is transferred from the directional (classical kinetic) energy to the uncertainty (quantum mechanical zero-point) energy. Show more

Keywords: Uncertainty, field particle, uniform magnetic field, quantum mechanical expansion, anomalous diffusion

DOI: 10.3233/JAE-162204

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1237-1244, 2016

Authors: Uetsuji, Yasutomo | Wada, Takeshi | Tsuchiya, Kazuyoshi

Article Type: Research Article

Abstract: In this paper, the effective physical properties were numerically investigated for polycrystalline multiferroic composite materials consisting of ferroelectric BaTiO3 and ferromagnetic CoFe2 O4 phases. An asymptotic homogenization theory was employed for scale-bridging between macrostructures and microstructures. The microstructural crystal orientations of both phases were assumed to be perfectly poled and the volume fraction of ferroelectric phase was changed from 0% to 100%. And then the homogenized physical properties of macrostructure, such as elastic stiffness, electric permittivity, magnetic permeability, piezoelectric and piezomagnetic stress constants, magnetoelectric constants, were estimated through the multiscale finite element analysis. Especially the local piezoelectric or …piezomagnetic constants of each phase were virtually varied and their influence on the global magnetoelectric constant was discussed to understand ideal material combination. Show more

Keywords: Multiferroic composite, polycrystal, magnetoelectic effect, multiscale FEA, homogenization method

DOI: 10.3233/JAE-162228

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1245-1250, 2016

Authors: Woo, Kyung-Il | Park, Han-Seok

Article Type: Research Article

Abstract: In this paper, torque characteristic analysis of flux switching motor by using winding function theory is described. First of all, the torque characteristic of existed flux switching motor was analyzed by winding function theory. The optimized new flux switching motor which has redesigned rotor teeth was proposed to minimize the torque ripple by using the optimum design method, such as Kriging method based on latin hypercube sampling and genetic algorithm. The inverse air gap function of new flux switching motor was calculated by winding function theory and the torque characteristic of that was compared with that of finite element analysis. …The revised flux switching motor and experimental systems were manufactured. The simulation results were compared with those of experiment. From the comparison it was shown that the analysis method of flux switching motor by winding function theory was validated. Show more

Keywords: Flux switching motor, finite element analysis, Kriging method, winding function theory

DOI: 10.3233/JAE-162143

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1251-1256, 2016

Authors: Wu, Jianbo | Hui, Fang | Long, Li | Yihua, Kang

Article Type: Research Article

Abstract: To improve the accuracy of the magnetic flux leakage (MFL) testing in practical application, we analyzed the signal characteristics of rectangular induction coil affected by the sensor arrangement and scanning direction. On the basis of magnetic dipole theory, the descriptions for the MFL field distributions of standard discontinuity were established. Further, based on Faraday's law of induction, the signal characteristics of rectangular induction coils were calculated and it was found that the signal waveform of the horizontal coil is similar with the x component of MFL; in contrast, the signal waveform of the vertical one has the same changing trend …with the z component of MFL. Finally, the influence of scanning direction was analyzed and found that different scanning directions will generate different signal characteristics; and that with the angle β between the coil and discontinuity orientation changing from 0 to π /2, the signal amplitudes of both induction coils decrease, which was verified by relevant experiments. Show more

Keywords: MFL (magnetic flux leakage), induction coil, output signal characteristic, arrangement direction, scanning direction

DOI: 10.3233/JAE-162151

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1257-1265, 2016