International Journal of Applied Electromagnetics and Mechanics - Volume 35, issue 1

Authors: Kan, Junwu | Wang, Shuyun | Wen, Jianming | Cheng, Guangming | Zeng, Ping | Fu, Xiaoqing

Article Type: Research Article

Abstract: This paper introduced a novel constant-stress piezoelectric cantilever generator (CSPCG) for human-powered battery-less remote controls (switches). The CSPCG consists of a piezoelectric monomorph cantilever and a deflection-limiting device (DLD). The DLD was designed to be a circular arc to shape the bended cantilever and yield constant strain through length. Considering the energy converting ability and reliability, the DLD's radius was figured out as a function of working stress and thickness of the piezoelectric …plate and substrate plate. Contrasted with a deflection-free piezoelectric cantilever generator (DFPCG), the energy performance of the CSPCG was evaluated. Research results show that the two generators share the same optimal thickness ratio for them to achieve the maximal electric energy output. When the same stress and end-deflection were provided, the electric-energy generation of the CSPCG is above 4 and 1.5 times that of the DFPCG, respectively. While, the stress and end-deflection of the CSPCG is only 0.49 and 0.77 times that of the DFCPG when equal electric energy is generated. This suggests that a CSPCG with a DLD can enhance energy-generating capability and reliability, or decrease end-displacement of piezoelectric cantilever. A CSPCG was fabricated and used to power a low-power remote-control circuit at one-push excitation. Show more

Keywords: Energy generation, constant stress, piezoelectric generator, wireless remote control, battery-less

DOI: 10.3233/JAE-2011-1316

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 35, no. 1, pp. 1-13, 2011

Authors: Traxler, Stefan | Pfútzner, Helmut | Mijanović, Lejla | Popović, Jovana | Kaniusas, Eugenijus | Futschik, Karl

Article Type: Research Article

Abstract: The paper concerns a detector for biomedical screening of sleep apnea which may yield severe reduction of life expectation. The detector is mounted on the thorax including several sensors for respiratory and cardiac activities. An additional magneto-elastic sensor, which is described in this paper, should register both the body position and body movements, both being relevant for diagnostics. The sensor is based on a magneto-elastic bilayer of high bending sensitivity operated in acceleration mode. …The sensor is being optimized with respect to material matching, loading (mass optimization) and length, as well as (limited) excursion, resonance frequency and thermal behavior. Application is reported for lab tests on short time events of three kinds: (a) body positions, with focus on back position which favors positive findings, (b) body movements, ranging from arm/leg movements up to upper body rolls, and (c) physiological activities such as respiration, indicating additional potentials of the sensor. The magnetic concept promises a component which is compact, robust, free of wear and cheap. It will be used in combination with sensors for respiration effort and cardiac activity, aiming for a robust single-spot home monitoring device for the assessment of sleep apnea syndrome. Show more

Keywords: Magnetostriction, magneto elasticity, acceleration, biomedical transducers, sleep monitoring

DOI: 10.3233/JAE-2011-1318

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 35, no. 1, pp. 15-24, 2011

Authors: Kuo, Chia-Lung | You, Jr-Shiang | Hwang, Shun-Fa

Article Type: Research Article

Abstract: In the electromagnetic forming (EMF) process, the Lorentz force is generated by the repulsive interaction of magnetic field between a pulse transient current in a coil and an eddy current in a workpiece. During the process, the current will generate Joule heat in both the coil and workpiece raising their temperatures. The objective of this work is to build a coupled analysis to consider the temperature effect during the electromagnetic sheet metal forming process by using …a finite element analysis. During the analysis, the electromagnetic, mechanical and temperature problems are considered simultaneously. Then, the coupling effects of the temperature with eddy currents, magnetic fields, magnetic force density, and deflection of the sheet metal are discussed. The results indicate that the temperature increasing is significant especially during repeated working cycles, and the deflection of a sheet metal is reduced as the increasing of the coil temperature. Hence, this temperature effect should be considered to avoid the failing of products and to improve the life of the forming coil, especially in a mass production process. Show more

Keywords: Electromagnetic forming, sheet metal forming, high forming rate, finite element analysis, temperature effect

DOI: 10.3233/JAE-2011-1319

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 35, no. 1, pp. 25-37, 2011

Authors: Smail, Mostafa Kamel | Pichon, Lionel | Olivas, Marc | Auzanneau, Fabrice | Lambert, Marc

Article Type: Research Article

Abstract: This paper presents an effective technique to reconstruct faulty wiring networks and/or to localize the defects affecting the branches of a wiring network from the reflectometry response. The direct problem (propagation in the cables) is modelled by RLCG circuit parameters and the Finite Difference Time Domain (FDTD) method whereas the inverse problem is solved using Genetic Algorithms (GAs). In a first step the forward problems is validated by comparison with experimental and simulated data. In a …second step the proposed reconstruction method is applied on different configurations and the results are discussed. Show more

Keywords: Wiring network, faults, FDTD method, time domain reflectometry, reconstruction, and genetic algorithm

DOI: 10.3233/JAE-2011-1320

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 35, no. 1, pp. 39-55, 2011

Authors: Bai, Yaxiang | Hu, Yucai | Li, Xinjun

Article Type: Research Article

Abstract: The influence of operating parameters on the drying rate and energy consumption of Electrohydrodynamic (EHD) has been experimentally evaluated in this study. Tofu contained in the Petri dish was put in EHD system which was made up of a wire pole and a plate pole. By changing the voltage, the electrode spacing and the distance between the two neighboring wires, the factors related to the drying rate and energy consumption were quantitatively studied. The results indicate …that when the distance between the wire electrodes and the surface of the plate pole is constant, the drying rate increases linearly while the drying energy consumption increases nonlinearly with the supplied voltage. When the supplied voltage is not changed, the tofu drying rate and energy consumption are changed with the distance between the two neighboring wires. When the distance between the two neighboring wires is not changed, the tofu drying rate and energy consumption are changed with the electrode spacing. When the electrode spacing is 9 cm and the distance between the two neighboring wires is 9 cm, the drying rate is the highest while the energy consumption is relative least, 45 kV is the optimum value for drying voltage. Show more

Keywords: Electrohydrodynamic (EHD), drying, drying rate, energy consumption, the distance between the two neighboring wires, the electrode spacing

DOI: 10.3233/JAE-2011-1321

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 35, no. 1, pp. 57-65, 2011

Authors: Zhang, Da-Guang | Zhou, You-He

Article Type: Research Article

Abstract: In this paper, a new theory about functionally gradient materials (FGM) is constructed from the concept of physical neutral surface and classical double curved shallow thin shell theory (CDSST). In this theory, there is no stretching-bending coupling effect in constitutive equations, governing equations and boundary conditions have the simple forms as those of CDSST about homogeneous isotropic materials, so the solution procedure is as easy as homogeneous isotropic shell. Using this new theory, linear bending and …vibration solutions are presented using analytical method and a nonlinear bending approximate solution is given out using Galerkin variational method. This new theory about FGM has more merits in engineering applications, because it is easier and simpler than any of geometric middle surface FGM double curved shallow shell theories. Show more

Keywords: Physical neutral surface, functionally graded materials, double curved shallow thin shell, stretching-bending coupling, bending, vibration, nonlinear bending

DOI: 10.3233/JAE-2011-1322

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 35, no. 1, pp. 67-78, 2011