International Journal of Applied Electromagnetics and Mechanics - Volume 28, issue 4

Authors: Chen, Hung-Cheng | Huang, Kuo-Hua

Article Type: Research Article

Abstract: The analysis of an induction heating cooker is a complex process because induction heating is a combination of electromagnetic and heat transfer. In this paper, a coupled electromagnetic and thermal field analysis tool for education is proposed. The tool is based on the finite element method. A very simple and highly practical finite element computation procedure has also been developed, coded, implemented, and intensively used to simulate and analyze the above problem in a multiphysics environment. …Particular attention is given to graphically visualizing the magnetic flux density of a specified induction heating cooker geometry. The corresponding induced eddy current density profile and temperature distribution are also presented. It gives a deeper insight into both electromagnetic and thermal phenomena for students. The forces on the plate caused by the eddy currents can also be studied and demonstrated in the numerical model. Combinations of geometric display and graphically parametric representations are effective for students to understand the designed induction heating cooker performance. The finite element simulation results of the transient temperature distribution are evaluated and compared with the experimental results. The accuracy of the simulation is demonstrated and appreciated. This finite element simulation and graphical visualization are therefore proposed as a valuable alternative prior to the actual final induction heating cooker design. Furthermore, in order to take care of the possible biological effects, some effort is expended to eliminate electromagnetic leakage emitted by the induction heating cooker. Show more

Keywords: Electromagnetic coupling, electromagnetic forces, eddy current, finite element method (FEM), induction heating, numerical simulation

DOI: 10.3233/JAE-2008-994

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 4, pp. 413-427, 2008

Authors: Abbasi, K. | Ito, S. | Hashizume, H.

Article Type: Research Article

Abstract: This paper presents a technique using microwaves nondestructive testing to detect circumferential crack and its location in stainless steels pipe. This approach is based on the surface current flow in the inner surface of the test pipe, when electromagnetic (EM) waves are propagating inside the pipe. Since the conductive pipe is an excellent waveguide, EM-wave can be propagated inside the pipe above the cutoff frequencies in large distances. To detect circumferential crack in pipes, a suitable …EM-wave mode is generated in the inspected pipe with crack. For this purpose, a mode-converter is used to convert rectangular TE_{10} -mode to the circular TM_{01} -mode. This mode is controlled and resonated by a moving a plunger mounted in the mode-converter. To show the crack existence from experimental data, the background signal of a pipe without a crack is subtracted from that one with a crack. The location of the crack is found by knowing the time of flight (TOF) of the reflected waves and the group velocities of the waves in each part of the waveguides used in this study. The TOFs are obtained through an analysis based on the Inverse Fast Fourier Transform (IFFT) of the signals in the frequency domain and a method of signal cancellation. The obtained results show that this NDT method is suitable for determining of crack locations in large pipes without point-by-point screening since electromagnetic waves above their cutoff frequencies can propagate in pipes without significant attenuation loss. Our study is of a fundamental interest in nuclear power plants and piping systems. Show more

Keywords: Non destructive testing (NDT), electromagnetic waves, time of flight (TOF), inspected pipe, Inverse Fast Fourier Transform (IFFT)

DOI: 10.3233/JAE-2008-995

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 4, pp. 429-439, 2008

Authors: Zhang, C.L. | Yang, J.S. | Chen, W.Q.

Article Type: Research Article

Abstract: Two-dimensional equations for laminated multiferroic shells of piezoelectric and piezomagnetic layers are obtained from the exact three-dimensional equations. Mechanically, the two-dimensional equations represent the so-called first-order theory that describes coupled extensional, flexural and thickness-shear motions. The electric and magnetic fields are described layer by layer. The two-dimensional equations obtained are used to study magnetoelectric coupling in a laminated multiferroic circular cylindrical shell. Both static coupling and the frequency dependence of the coupling …in time-harmonic motions are examined. Show more

Keywords: Multiferroic shell, magnetoelectric coupling, statics, time-harmonic motion, two-dimensional theory

DOI: 10.3233/JAE-2008-996

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 4, pp. 441-454, 2008

Authors: Xu, Limei | Wu, Han | Fan, Hui | Xiao, Zhongmin | Yang, Jiashi

Article Type: Research Article

Abstract: We perform a theoretical analysis on a ceramic plate piezoelectric transformer operating with thickness-twist modes. Mindlin's first order theory of piezoelectric plates is employed. Forced vibration solution is obtained. Transforming ratio and vibration mode shapes are calculated. The effects of plate thickness, electrode dimension and inertia are examined. The results are useful to the understanding of the operating principle and the design optimization of the transformer.

Keywords: Piezoelectricity, plate, transformer

DOI: 10.3233/JAE-2008-997

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 4, pp. 455-467, 2008

Authors: Rho, Jong-Seok | Lee, Chang-Hwan | Jung, Hyun-Kyo

Article Type: Research Article

Abstract: The exact analysis of the piezoelectric motor has been impossible to the present time, although many researchers have proposed various kinds of analysis method for the piezoelectric motor using numerical method or analytic method. Also, the arranged design method has not been suggested for the Ultra-Sonic Motor (USM) taking the characteristic into account. In order to address these problems, we propose the analysis and design method for the USM using analytic method combined with numerical method. …This method was named as the Cutting Method (CM) in this paper. The 8.5[mm] diameter Rotary Ultra-Sonic Motor (RUSM) is developed using the CM to verify the suggested method and for the demand of small actuators in industry. Finally, the proposed analysis and design method was validated by comparing its outcomes with the experimental data. For the vibrator of the proposed 8.5[mm] diameter RUSM, four kinds of comb-tooth structures were prototyped in this research. Hence, the relation between the speed of the motor and the number of teeth is revealed for the first time. This is noteworthy because the tooth design method has not been proposed and because this result also verified the proposed CM. Show more

Keywords: Actuator, analysis, design, FEM, FDM, rotary motor, piezoelectric, small size, ultrasonic motor

DOI: 10.3233/JAE-2008-999

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 4, pp. 469-500, 2008