International Journal of Applied Electromagnetics and Mechanics - Volume 10, issue 1

Authors: Andriollo, M. | Martinelli, G. | Morini, A. | Tortella, A.

Article Type: Research Article

Abstract: The paper describes a fully automated procedure to optimize the configuration of the magnetic circuit in EMS-MAGLEV systems. The procedure elaborates the results obtained through FEM numerical analyses and automatically re-defines the parameters of the configuration to minimize a suitable objective function, which takes into account both significant electromagnetic quantities and design constraints.

DOI: 10.3233/JAEM-1999-125

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 10, no. 1, pp. 1-19, 1999

Authors: Fanni, A. | Giacinto, G. | Marchesi, M. | Serri, A.

Article Type: Research Article

Abstract: A tabu search based strategy has been developed to achieve design optimisation of electromagnetic structures. Tabu Search (TS) is a metaheuristic that guides the search for the optimal solution making use of flexible memory systems which exploit the history of the search. It consists of systematically prohibiting some solutions to prevent cycling and, at the same time, avoiding to be trapped in local minima, and deeply explores the search space to minimise the objective function. Since the variables to be optimised are continuous in nature, we developed a continuous tabu search algorithm in which the range of variation of each …variable is discretised by division into sub-ranges. In this way, it is possible to identify a finite alphabet and apply tabu search strategies. Best performances have been reached by coupling tabu search with other optimisation procedures, such as Golden Search (GS) and a non-linear Simplex (SX) method. The algorithm is compared with more traditional methods on a Magnetic Resonance Imaging (MRI) design problem, showing a good performance improvement. Show more

DOI: 10.3233/JAEM-1999-126

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 10, no. 1, pp. 21-31, 1999

Authors: Fanni, Alessandra | Marchesi, Michele | Serri, Antonino | Usai, Mariangela

Article Type: Research Article

Abstract: This paper is concerned with the problem of adapting the optimization algorithms to the dimension of the problem at the hand. As test case, the problem of designing the structure of a magnetic resonance imaging system is considered with different number of optimization variables. A greedy genetic algorithm for continuous variables electromagnetic optimization problems, already presented in literature, has been modified to consider different problem sizes. A detailed comparison of performances obtained implementing several strategies and tuning of optimization parameters is eventually presented.

DOI: 10.3233/JAEM-1999-127

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 10, no. 1, pp. 33-43, 1999

Authors: Chonan, Seiji | Jiang, Zhong Wei | Tanaka, Mami | Tanikawa, Jun | Hirano, Kentaro | Orikasa, Seiichi | Namima, Takashige | Uchi, Keiichiro

Article Type: Research Article

Abstract: This paper is concerned with the development of an artificial urethral valve for treating urinary incontinence, which is driven by shape memory alloy actuators. Two types of valves, one with hand-drum form and the other with cylindrical configuration, are assembled and their opening and closing functions are examined experimentally by using the urethrae of male dogs. It is found that the clyindrical valve is better than the hand-drum form from the point of contact pressure with the urethra. A thermo-metallurgical-mechanical model of the SMA plate is constructed and applied to the analysis of opening/closing functions of valve. It is shown …that the presented model well describes the motor functions of the artificial urethral valve. Show more

Keywords: urinary incontinence, lower urinary tract, artificial urethral valve, shape memory alloy, animal experiment, analytical model

DOI: 10.3233/JAE-1999-128

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 10, no. 1, pp. 45-62, 1999

Authors: Yang, Z.J. | Hull, J.R. | Lockwood, J.A. | Rossing, T.D.

Article Type: Research Article

Abstract: We derive closed-form expressions for the magnetic forces and torques between two coaxial square current loops as a function of their relative tilt angle. These expressions involve simple numerical integrations. An analytic expression for the torsion constant at zero tilt angle is derived for loop filaments and for loops of finite axial extent.

Keywords: magnetic bearing, magnetic force

DOI: 10.3233/JAEM-1999-129

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 10, no. 1, pp. 63-76, 1999

Authors: Yoshida, Y. | Bowler, J.R.

Article Type: Research Article

Abstract: A volume integral formulation utilizing the vector potential dyadic Green’s function is applied to the computation of eddy current probe response due to a long crack. In addition to the ideal crack model, a thin crack model is proposed which takes into account the effect of crack opening on the measurement signal. To deal with the infinitely long crack, the spatial Fourier transform is applied to the boundary integral equation based on the vector potential integral formulation and then the method of moments is used to discretize the resultant equation. The proposed method is validated through the comparison of the …computed results with measurements. Show more

DOI: 10.3233/JAE-1999-130

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 10, no. 1, pp. 77-89, 1999