• Journal of Korean Society of Steel Construction
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• v.8 no.3 s.28
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• pp.13-20
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• 1996

With the adoption of welded joints rather than bolted joints, we investigate the fatigue strength and the fatigue crack initiation of U-type trough rib and welded specimen with misalignment in a steel deck plate. The stress concentration factor of welded specimens with a misalignment is also verified by a finite element method. The main conclusions obtained from this study are as follows Experimental results of full-scaled U-type trough rib models have indicated that fatigue life depends on misalignments of welded joints in steel deck plate ; The more misalignments are, the less the fatigue life is. It has also shown that fatigue crack propagates from the welded root to the bead surface. We have also obtained the same results from both the fatigue test of welded specimens with a misalignment and the stress analysis of a finite element method.

• Journal of applied mathematics & informatics
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• v.22 no.1_2
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• pp.523-533
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• 2006

We analyze two finite buffers queueing system with priority scheduling dependent upon queue length. Customers are classified into two types ( type-l and type-2 ) according to their characteristics. Here, the customers can be considered as traffics such as voice and data in telecommunication networks. In order to support customers with characteristics of burstiness and time-correlation between interarrival, the arrival of the type-2 customer is assumed to be an Markov- modulated Poisson process(MMPP). The service order of customers in each buffer is determined by the queue length of two buffers. Methods of embedded Markov chain and supplementary variable give us information for queue length of two buffers. Finally, performance measures such as loss and mean delay are derived.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.2
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• pp.74-78
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• 2003

This paper describes the operating characteristic analysis of the PM-type linear oscillatory actuator used as a magnetic circuit breaker for the electromagnetic field, electric circuit, and mechanical motion problems. Transient calculations are based upon a 2D finite element magnetic field solution including non-linearity of materials. Changes of the dynamic characteristics from the eddy current in the plunger are quantified from finite element analysis. A new laminated model is proposed to decrease the eddy current effect.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.12
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• pp.789-796
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• 2000

This paper deals with magnetic field and characteristic analysis for ring type slotless synchronous motors by using analytical method. Since magnetic air-gap in the slotless motors is much larger than mechanical air-gap, it is necessary to analyze the magnetic flux distribution at the whole magnetic airgap region. therefore, this paper analyzes the duplicated magnetic field derived by both Permanent Magnet(PM) and armature current and estimates the back electromotive force and torque characteristic by subdividing the conductor region. The analysis results are verified by comparing with Finite Element Analysis(FEA) results.

• Progress in Superconductivity
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• v.3 no.2
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• pp.183-187
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• 2002

In this paper we analyzed the electromagnetic behavior of high $-T_{c}$ superconductor under the quench state using finite element method. Poisson equation was used in finite element analysis as a governing equation and was solved using algebra equation using Gallerkin method. We first investigate d the electromagnetic behavior of U-type superconductor. Finally we applied our analysis techniques to 5.5 kVA meander-line superconducting fault current limiters (SFCL) which are currently developed by many power-system researcher in the world. Meshes of 14,600 elements were used in analysis of this SFCL. Analysis results show that the distribution of current density was concentrated to inner curvature in meander-line type-superconductors and maximum current density 14.61 $A/\m^2$ and also maximum Joule heat was 6,420 W/㎥. We concluded that this meander line-type SFCL was not pertinet fur uniform electromagnetic field distribution.n.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.4
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• pp.280-285
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• 2000

The conventional ultrasonic linear motors developed so far utilize a standing wave and are of a pi-type or a hybrid transducer type structure. Traveling wave type bi-direction linear motors have not been developed yet. This paper describes design of a new bi-directional ultrasonic linear motor working by means of a traveling wave. With the finite element method we design and verify validity of the new structure. And we determine its optimal structure size of design variables material and boundary conditions for proper generation of the traveling wave.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1338-1346
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• 1994

The objective of this study is to investigate the effect of various parameters, such as temperature, mean current density and voltage on the performance of phosphoric acid fuel cell (PAFC) by numerical analysis. Two types of flow passages, which are Z-parallel type and Z-counter type, are evaluated to obtain the best current density and temperature distribution. Parametric studies and sensitivity analysis of the PAFC system's operation in single cell are accomplished. A steady state simulation of the entire system is developed using nonlinear ordinary differential equations. The finite difference method and trial and error procedures are used to obtain a solution.

• 전기의세계
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• v.29 no.10
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• pp.653-659
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• 1980

The paper describes a new technique for the shape design of a bell-type porcelain locke insulator in contaminated environment. Early studies on the contamination performance of insulators indicated the need for an improvable shape to provide adequate insulation strength at normal operating voltages. In this paper, under lightly and heavily contaminated site severity, the variation of voltage distribution to leakage path at insulator surfaces analyzed by the complex admittance matrix using finite element method. By this results, the improvement of shape of insulators could be approached to the available condition in contaminated environments. In applicating to compare a standard disc type with a fog disc type insulator, this design technique is valid.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.309-314
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• 2011

Outer rotor type in-wheel switched reluctance motor for Welfare neighborhood electric vehicle is researched. In-wheel system is to drive the electric vehicle without mechanical transmission, shaft, differential gears or other mechanical system. To calculate drive power for each wheels, the elder's and disable's safety driving conditions are considered. The designed outer rotor SRM has a 6-stator and 8-rotor pole. The determined dimensions as well as the stator and rotor pole arc are simulated and tested with CAD and finite element analysis to verify the performance of the proposed motor.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.2
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• pp.63-68
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• 2004

This paper presents an approach to optimum design of Moving Magnet Type Linear Oscillatory Actuator(MM-LOA). The Finite Element Method is applied to characteristic parameters for characteristic analysis and in order to reduce modeling time and efforts, the moving model node technique is used. In addition the neural network is used to reduce computational time of analysis according to changing design variable. To confirm the validity of this study, optimum design results are compared with results of analysis procedure that is verified by experiment.