• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.2
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• pp.164-172
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• 2014

This paper presents an analysis of a leakage inductance for a toroidal type flyback transformer. The equation to calculate the leakage inductance is derived using the MMF diagram of the transformer. The analysis for the different types of the cores and winding structures is also provided using the FEM simulation. The winding structures minimizing the leakage inductance are finally discussed from the simulation and experimental results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.95-100
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• 2004

An analysis using FEM simulation was conducted to predict residual stresses and birefringence in simple compressed cylindrical glass as a preliminary part of the optimum design determination of optical lenses. The FEM simulation with the Maxwell viscoelastic constitutive model was used to predict thermal induced residual stresses and birefringence during the compression test considering stress relaxation. Also the linear photoelastic theory was introduced to calculate birefringence from the residual stress state. The simulation results were in good agreement with deformation and birefringence distribution in the existing experimental result.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.201-207
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• 2015

In this paper, in order to avoid equipment malfunction due to electromagnetic waves, which can occur when high-voltage live line diagnostic device fabrication, the enclosure structure of the diagnostic device with power lines that can minimize the EMI (electromagnetic interference) was modeled using the FEM (finite element method). Simulation examined the strength of the electric field in the required thickness, material and regions where there is a control board while changing the curvature radius of the corner making the enclosure, and By applying a mechanical design and simulation results that occur during the actual production has been designed for the final design. Most of the simulation results for the electric field is concentrated in the final model, the inner edge of the enclosure could be confirmed that the stable structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.210-210
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• 2010

에너지 하베스트 기술은 자연의 빛에너지, 휴대용 기기 탑재/부착장치의 미세 진동에너지, 걷거나 뛰는 인간의 신체활동으로 인한 소산에너지 등을 흡수하여 전기에너지로 변환, 전자기기의 전력으로 사용하는 재생형 에너지원이다. 본 논문에서는 그 중 주변 환경에서 에너지를 끌어 쓸 수 있는 기술 중 압전 효과 방식을 이용한 진동 형태의 에너지 하베스트 기술을 활용하여 설계하고 FEM simulation을 통해 분석해보았다. 압전 물질로는 PZT를 사용하고 메탈기반의 캔틸레버로는 구리를 사용하여 크기를 길이, 넓이, 폭 각각 $6{\times}4{\times}0.025mm^3$으로 모델링하여 444Hz의 공진주파수에서 응력이 $2.68e^{+5}Pa$ 발생하는 결과를 얻었다. 그 결과 $d_{33}$ 모드의 전극형태에서 전압을 2.56V 얻을 수 있음을 추론할 수 있었다.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.471-476
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• 2001

The main object of this study is to develop a reliable FEM simulation technique for stability test using ABAQUS software and to clarify the effect of base profile of a steel D&I(drawn and ironed) can on the dome reversal pressure. For the can after body making simulation, two kind of stability test, dome buckle test and axial crush test are performed. The factors studied in the base profile on the dome reversal pressure are the base diameter, the rim radius, the dome shoulder radius, the dome radius and the dome depth. Within the limits before the occurrence of normal snap-through buckling of dome, the dome reversal pressure is improved by decreasing the base diameter, increasing the dome depth or increasing the dome shoulder depth.

• Interaction and multiscale mechanics
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• v.2 no.4
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• pp.353-374
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• 2009

A new seamless multiscale simulation was developed for coupling the continuum model with its molecular dynamics. Kriging-based Finite Element Method (K-FEM) is employed to model the continuum base of the entire domain, while the molecular dynamics (MD) is confined in a localized domain of interest. In the coupling zone, where the MD domain overlaps the continuum model, the overall Hamiltonian is postulated by contributions from the continuum and the molecular overlays, based on a quartic spline scaling parameter. The displacement compatibility in this coupling zone is then enforced by the Lagrange multiplier technique. A multiple-time-step velocity Verlet algorithm is adopted for its time integration. The validation of the present method is reported through numerical tests of one dimensional atomic lattice. The results reveal that at the continuum/MD interface, the commonly reported spurious waves in the literature are effectively eliminated in this study. In addition, the smoothness of the transition from MD to the continuum can be significantly improved by either increasing the size of the coupling zone or expanding the nodal domain of influence associated with K-FEM.

• Transactions of Materials Processing
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• v.6 no.3
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• pp.233-238
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• 1997

The estimation of the forming force required for metal forming process is unavoidable for selecting suitable machine and dimensioning die and punch parts. For this purpose the upper-bound method turns out to be very practical in simple two-dimensional cases under well-known boundary conditions. However, the application of this method for complicated two-or three-dimentional cases is very limited or practically impossible. The modified application of FEM in a manner of applying the upper bound method(the so-called Upper-bound Finite Element Simulation Method) fortunately provides the posibility of getting important information about the forming process in a simple and quick way before realizing the process on the machine. It is expected to function successfully even in three-dimentional cases. The application procedure has been explained for two-dimensional cases and its usefulness shown.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1852-1857
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• 2003

This study is concerned about the development of three-dimensional bending machine for heat exchanger. Recently, three-dimensional bending is required for various heat exchanger. The purpose of this study is design of three-dimensional bending machine by analysis of bending process and structural analysis simulation. The analysis is carried out by FEM simulation using DEFORM and CATIA V5 software. The copper-tube is modeled by shell elements and the machine is modeled by placing proper shell and solid finite elements and fictitious mass properties to represent the real one. The final results of analysis are applied to the design of three-dimensional bending machine and the machine is successfully developed.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.983-984
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• 2006

The correct computer simulation of the powder compaction stage requires the determination of the elastoplastic parameters which characterize its mechanical behavour. Instrumented dies are frequently used to monitor the longitudinal and radial stress occurring during powder compaction. When strain gages are employed a previous calibration is needed. Many sources of error exist that can lead to the incorrect calibration of the instrumented die. By means of a FEM simulation some of these problems are analysed. The effect of die wall thickness, compression length, and strain location are studied.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.829-832
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• 2006

In this study, the influence of the magnetic field on ferrite slurry's injection time during the slurry forming process was investigated. The evaluation system of the slurry's injection time under the strong magnetic field was designed with FEM and manufactured. Studied parameters were the applied magnetic field, the input pressure of the slurry, and the supplying tube materials. As the results, the injection time was increased with the external magnetic field strength and rapidly decreased with increasing the input pressure of the slurry. Also the injection time was decreased when the supplying tube was manufactured with the magnetic material having the higher magnetic permeability than the ferrite.