• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1041-1042
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• 2007

This paper proposes a new method for detecting broken rotor bars in a squirrel-cage induction motor. The air-gap flux variation analysis was done using search coils inserted in stator slots when broken rotor bar occurs. An accurate modeling and analysis of air-gap flux variation in the induction motor are developed using finite-element (FE) software packages, and measurement of the flux are made using search coils. The simulation was done for the induction motor with 380 [V], 7.5 [kW], 4 Poles, 1,760 [rpm] ratings using the commercial FE analysis tool. The simulation and experiment results can be useful for detecting the broken rotor bar of an induction motor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.393-396
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• 2005

This paper is concerned with the drawing process of $Al-1\%Si$ bonding wire. In this study, the finite-element model established in previous work was used to analyze the effect of various forming parameters, which included the reduction in area, the semi-die angle, the aspect ratio, the inter-particle spacing and orientation angle of the fine Si particle in drawing processes. The finite-element results gave the consolidation condition. From the results of analysis, the effects of each forming parameter were determined. It is possible to obtain the Important basic data which can be guaranteed in the fracture prevention of $Al-1\%Si$ wire by using FE-Simulation.

• Transactions of Materials Processing
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• v.25 no.6
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• pp.366-372
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• 2016

Recently, the amount of spring usage is on the increase in the automotive and aircraft parts industries as well as home appliances. Manufacture of spring reflects a need for diversification, mass production and high precision. Therefore it is very important to know the bending method and forming technique according to the shape of spring. In this study, to find the optimal bending method for the motor spring, the FE-simulation was executed using orthogonal array. The design parameters are wire length, length of vibration and feed rate. Then, the optimal combination of design parameters was suggested using ANN technique.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.142-148
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• 2004

It is already known that hardness number of cold-forged product is in close conjunction with its effective strain. This paper presents the method to predict the relation between effective strains and hardness by using FE-simulation of hardness test from the conception that hardness indicates resistance to plastic deformation. The results of FE-simulation for the materials are compared with those of experiments and also compared with those of experiments in reference to show the feasibility of the proposed method. In addition, the present method was applied to the cold-forged product to verify the relation between hardness and effective strain. As a result, the predicted hardness number by the present method is in good agreement with experimental values. Prediction of hardness fur a cold-forged product comes to be possible by estimating the relation between effective strain and hardness using the proposed method in this study.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.404-407
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• 1995

Magnetic properties of model exchange-spring magnets, which are composed of magnetically soft and hard grains, were calculated by means of computer simulation. The dependence of the magnetic properties on the strength of intergrain exchange interaction and the amount of soft grains was studied. The existence of soft grains enhanced the remanence remarkably, and the remanence over $0.8M_{s}$ was obtained in the model magnets containing 25% or more soft grains by volume. The calculated coercivity vs. the strength of the exchange interaction curves showed a peak at a critical strength of the exchange interaction, although the remanence increased monotonously with increase in the strength of the exchange interaction. Thus the maximum energy product also reached a peak around the same critical strength. The calculated maximum energy product exceeded $300kJ/m^{3}$ when the magnet is assumed to be composed of $Fe_{3}B$ and $Nd_{2}Fe_{14}B$.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.477-481
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• 1998

This paper describes the application of a coupled finite element-boundary element method to obtain the steady-state response of a hydrophone. The particular structure considered is a flooded piezoelectric spherical shell. The hydrophone is three-dimensionally simulated to transduce an incident plane acoustic pressure onto the outer surface of the sonar spherical shell to electrical potentials on inner and outer surfaces of the shell. The acoustic field formed from the scattered sound pressure is also simulated. And the displacement of the shell caused by the externally incident acoustic pressure is shown in temporal motion. The coupled FE-BE method is described in detail.

• Journal of the Korean Data and Information Science Society
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• v.17 no.4
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• pp.1299-1307
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• 2006

This study investigates solving production problems in an automotive stamping plant using Finite Element (FE) analysis. The fundamentals of stamping, metal plasticity and FE analysis are developed. In this paper, we provide the basis for a simulation of the stamping of a production part, the automotive rear floorpan. On-plant factorial Design of Experiments (DoE) were simulated using the floorpan model. The accuracy of the simulations was undetermined because of variability in the DoE results. Predictions of flange shape, wrinkling and thickness show qualitative agreement with manufactured parts and indicate that simulating an industrial part is feasible.

• Journal of Sensor Science and Technology
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• v.8 no.4
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• pp.298-307
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• 1999

This paper describes the application of the coupled FE-BEM (finite element-boundary element method) for the numerical harmonic analysis of the linear dynamic behaviour of a magnetostrictive Terfenol-D rod in water. The magnetostrictive rod is three-dimensionally simulated to transduce applied electric current in a helical coil around the rod to mechanical displacement. The theoretical derivation of the magnetostrictive matrix equation is described in detail. The steady-state resonance response of the displacement is shown. In addition, the directivity pattern and the radiation impedance are also shown.

• The Journal of the Acoustical Society of Korea
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• v.17 no.1E
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• pp.14-19
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• 1998

This article describes the application of a coupled finite element-boundary element method to obtain the steady-state response of a sonar transducer. The sonar shell is simulated to be driven by electrical charges applied onto inner and outer surfaces of the shell. It is shown that at relatively low input frequency a beam pattern which is almost close to omnidirection can be obtained. The coupled FE-BE method is described in detail.

• Journal of Magnetics
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• v.15 no.4
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• pp.149-154
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• 2010

Synthetic antiferromagnets (SAFs) are used as free layer structures for various magnetic devices utilizing spintransfer torque (STT). Therefore, it is important to understand current-induced excitation of SAFs. By means of drift-diffusion and macrospin models, we studied the current-induced excitation of a SAF-free layer structure (NiFe/Ru/NiFe). The simulation results were compared with the previous experimental results [N. Smith et al., Phys. Rev. Lett. 101, 247205 (2008)]. We confirmed that a nonzero STT through the Ru layer is essential for explaining the experimental results.