• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.3
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• pp.123-130
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• 2006

This paper presents characteristics analysis of skewed Synchronous Reluctance Motor using equivalent magnetic circuit and compares with the result of Finite Element Method. Torque ripple must be reduced, because it is producing noise and vibration. There is many kinds of method to reduce torque ripple, but generally we apply skewing stator or rotor. The 2D Finite Element Method(FEM) or 3D FEM is used to analyze the motor, since skew influence the average torque in the motor. However, the FEM takes much time in spite of the advanced computer and numerical technique. This paper will analyze characteristics of skewed synchronous reluctance motor using equivalent magnetic circuit.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.184-187
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• 2005

Forging process is one of the forming process and is used widely in automobile parts and manufacture industry. Especially the gears like spur gear, helical gear, bevel gear were produced by machine tool, but recently they have been manufactured by forging process. The goal of this study is to study forming process with data obtained by comparison between forward extrusion and upsetting simulation results and formability improvement by various heat treatment conditions. By analysis data of 3D FEM by upsetting and forward extrusion forming, the forming process of clutch gear develops using data based on 3D FEM analysis. Through tensile test using specimens by various heat treatment conditions, the optimal heat treatment condition is obtained by comparison the results of tensile test.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.4
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• pp.228-234
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• 2001

The present study was an attempt for systematic data conversion between FDM and FEM in order to evaluate the thermal stress distribution during quenching process. It has been generally recognized that FDM is efficient in flow and temperature analysis and FEM in that of stress. But it induced difficulty and tedious work in analysis that one uses both FDM and FEM to take their advantages because of the discrepancy of nodes between analysis tools. So we proposed field data conversion procedure from FDM to FEM in 3-dimensional space, then applied this procedure to analysis of quenching process. The simulation procedure calculates the distributions of temperature and microstructure using FDM and microstructure evolution equations of diffusion and diffusionless transformation. FEM was used for predicting the distributions of thermal stress. The present numerical code includes coupled temperaturephase transformation kinetics and temperature-microstructure dependent material properties. Calculated results were compared with previous experimental data to verify the method, which showed good agreements.

• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.39-53
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• 2019

Bi-directional pile load test (briefly called 'BDH PLT') cannot be performed at loading levels where ultimate bearing capacity could be assessed in field, it is not possible to precisely determine both ultimate load and yield load and under loading. Since the load is transmitted separately to the skin and the end unlike the static pile load test (briefly called 'SPLT') and the direction of loading on the skin is opposite, such methods could have a result different from actual movements of shafts. In this study, three-dimensional finite element method (briefly called '3D FEM') analysis was conducted from results of the BDH PLT, made with barret piles, which were large-diameter cast-in-place concrete piles, and the calculated design constants were applied to the 3D FEM analysis of the SPLT to interpret them numerically and then, actual behaviors of cast-in-place concrete piles were estimated. First, using the results of the BDH PLT with cast-in-place concrete piles, behaviors of the piles made by loading upwards and downwards were analyzed to calculate load-displacement. Second, the design constants, calculated by the 3D FEM analysis and the back analysis, were applied on the 3D FEM analysis for the SPLT, and from these results, behaviors of the SPLT through the BDH PLT was analyzed. Last, the results of the 3D FEM analysis of the SPLT through the BDH PLT was expressed in relationships as {A ratio of bearing capacity of the SPLT and of the BDH PLT (y)} ~ {A ratio of reference displacement and pile circumference (x)}, and they were all classified by reference displacement at 10.0 mm, 15.0 mm, and 25.4 mm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.306-310
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• 2014

The purpose of this study is the stability evaluation of a vacuum pump through modal test and rotor dynamics. Eigenvalue was solved by the finite-element method(FEM) using 2D and 3D models, then the modal test result was compared with the FEM result. According to the comparison, the analysis result using the 2D was more accurate than the 3D model. Therefore, rotor dynamics was performed by the 2D model. Campbell diagram and root-locus maps, which were calculated by complex-eigenvalue analysis, were used to evaluate the stability of the rotors of the vacuum pump. And displacement solved by unbalance response analysis was compared with the minimum clearance between two rotors of the vacuum pump. Thus, the vacuum pump is assumed operated under steady state through the evaluation of the rotor dynamics.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.750-751
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• 2008

본 논문은 컨버터용 변압기의 여자전류 해석을 통해 DC 성분 유입시 자속밀도-여자전류 곡선 그래프를 도출하여 철심포화 여부를 확인하며, 철심 공극에 의해 발생되는 누설자속(Leakage Flux)으로 인한 철구조물(Lock Plate)의 와전류 손실을 계산하였다. 변압기 해석을 위해 상용 해석 소프트웨어인 Maxwell 3D를 이용하였고, 철심의 비선형성을 고려하여 해석하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.11-17
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• 2000

,An residual stress and out-of plane deformation produced by butt welding was analyzed by four kinds of 3D-FEM programs(Thermal El-P1 Analysis) developed by authors. The magnitude of deformation of perpendicular to the welding line generated by butt welding was large when the reduced integration method was used. This was because of removal of the locking phenomenon, which it was generally known that the stiffness of the shear component of out-of-plane was largely evaluated. And the magnitude of residual stress was analyzed by using the FEM program based on a large and small deformation theory was similar to that was analyzed by the redeced integration method.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3E
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• pp.112-118
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• 2002

An unconstrained tuning fork with a 3-D model has been numerically analyzed by Finite Element Method (FEM) and Boundary Element Method (BEM). The first three natural frequencies were calculated by the FEM modal analysis. Then the trend of the change of the modal frequencies was examined with the variation of the tuning fork length and width. An formula for the natural frequencies-tuning fork length relationship were derived from the numerical analysis results. Finally the BEM was used for the sound pressure field calculation from the structural displacement data.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.3-6
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• 2006

In this study, 3D Design and the Structural Analysis using FEM are conducted for developing the Release Devices. On these bases the prototype devices are made and the reliability has been improved through many environmental tests.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1201-1204
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• 2003

An unconstrained tuning fork with a 3-D model has been numerically analyzed by Finite Element Method(FEM) and Boundary Element Method (BEM). The first three natural frequencies were calculated by the FEM modal analysis. Then the trend of the change of the modal frequencies was examined with the variation of the tuning fork length and width. An formula for the natural frequencies-tuning fork length relationship were derived from the numerical analysis results. Finally the BEM was used fur the sound pressure field calculation from the structural displacement data.