• Journal of the Korean Vacuum Society
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• v.1 no.2
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• pp.269-276
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• 1992

경계 요소법을 이용하여 Finely-focused ion beam 시스템을 위한 전계형 시뮬레 이터를 개발하였다. 경계 요소법을 시뮬레이터에 적용함으로써 기존의 유한 요소법, 차분근 사법에서는 피할 수 없었던 내부격자망 구성이 불필요하게 됨에 따라 계산속도를 현저히 줄 일 뿐만 아니라 불규칙 경계에 대한 요소분할이 가능하게 되어 최적렌즈구조 설계의 새로운 요소인 전극구조의 모양을 자유롭게 시뮬레이션 할 수 있게 되었다. 또한 개발된 시뮬레이 터를 이용하여 최적조건을 만족하는 구조를 제안한다. 이때 렌즈설계조건은 beam half-angle 3.0 mrad, working distance 50mm, 빔에너지 퍼짐 (beam energy spread) 10eV, 가속에너지 35keV이다.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.231-236
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• 2017

In this study, the inhomogeneous material composed of CFRP(carbon fiber reinforced plastic) and structural metal of SM45C is used for the light material. The finite element analysis on the basis of compact tension test was carried out by using the composite material for sandwich type bonded with the unidirectional CFRP that differs in fiber stacking angle at both sides with the core of SM 45C. CT test is the representative method to confirm the fracture behaviour due to crack in material under the load. The effect on crack and hole must be investigated in order to apply inhomogeneous material to mechanical structure. As the result of this study, the fracture behaviour by CT test of the composite material for sandwich was studied by simulation analysis. The sandwich composite of unidirectional CFRP with the stacking angle of [0/60/-60/0] has the superior strength and the maximum equivalent stress of about 182GPa.Also, the esthetic sense can be shown as the designed factor of shape with composite material is grafted onto the convergence technique.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.3
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• pp.48-58
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• 1999

In this paper, a new parallel computation method, which fully utilize the parallel processors both in mesh generation and FEM calculation for 2D/3D process simulation, is presented. High performance parallel FEM and parallel linear algebra solving technique was showed that excessive computational requirement of memory size and CPU time for the three-dimensional simulation could be treated successively. Our parallelized numerical solver successfully interpreted the transient enhanced diffusion (TED) phenomena of dopant diffusion and irregular shape of R-LOCOS within 15 minutes. Monte Carlo technique requires excessive computational requirement of CPU time. Therefore high performance parallel solving technique were employed to our cascade sputter simulation. The simulation results of Our sputter simulator allowed the calculation time of 520 sec and speedup of 25 using 30 processors. We found the optimized number of ion injection of our MC sputter simulation is 30,000.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.696-702
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• 2010

In many industrial applications, it is very important to control the temperature of the controlled object to the target temperature as closely as possible. Although it is apparent that the great obstacles in controller design are time-delay of the thermal responses of the controlled object and the effect of thermal interference between neighboring heating zones, one more fundamental obstacle is a very large amount of time which is required during repeated experiments in controller design process. Therefore, a convenient simulation environment, which can represent thermal behavior accurately within appropriate time, is needed. In this paper, a prototype of 2D FEM (finite element method) heat transfer simulation environment using MATLAB is constructed to be usefully adopted into industrial applications with temperature controller design.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.312-312
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• 2010

모터나 기계류와 같이 주변에서 발생하는 미활용 진동에너지를 전기에너지로 수확하기 위한 Piezoelectric Energy Harvester를 개발하고자 하였다. PZT-5H의 조성으로 후막세라믹 적층 구조 캔틸레버 타입의 압전시트를 통해 압전 에너지 하베스터를 제작하였다. 일반적으로 진동에너지를 수확하여 전기에너지로 변환시키는 압전 에너지 하베스팅 기술은 에너지 효율이 낮은 문제점을 가지고 있으므로 에너지 효율을 높이기 위한 방법으로 본 연구에서는 Unimorph 와 Bimorph 타입의 캔틸레버의 가로, 세로, 두께, 재료변수에 따라 발생하는 최적의 효율을 가지는 구조를 찾고자 하였다. 캔틸레버 각 변수에 따른 공진주파수 대역에서 발생하는 전압을 분석하여 50Hz의 공진주파수를 가지는 60*35*0.2mm의 캔틸레버를 설계하였다. 시뮬레이션을 통해 얻어진 결과를 실험적으로 검증하기 위해 전력량을 측정한 결과, Bimorph는 Unimorph 타입에 비해 2배가량의 향상된 발전특성을 가지며 에너지 하베스터에서 초당 $76.2\;{\mu}W$의 전력량을 가지는 것을 확인하였고 시뮬레이션 결과와의 타당성을 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.16-25
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• 2002

This paper presents a methodology and application for extracting parasitic inductances in a multi-level interconnect semiconductor structure by a numerical technique. In order to calculate the parasitic inductances, the distrubution of electric potential and current density in the metal lines are calculated by finite element method (FEM). Thereafter, the magneto-static energy caused by the current density in metal lines was calculated. The result of simulation is compared with the result of Grover equation about analytic simple structures, and 4 bit ROM array with a dimension of $13{\times}10.25{\times}8.25{\mu}m^3$ was simulated to extract the parasitic inductnaces. In this calculation, 6,358 nodes with 31,941 tetrahedra were used in ULTRA 10 workstation. The total CPU time for the simulation was about 150 seconds, while the memory size of 20 MB was required.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.1
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• pp.21-26
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• 2013

This study presents new analysis method to predict bending behavior of packaging substrate structure by comparing finite element method simulation and measured curvature using 3D scanner. Packaging substrate is easily bent and deflected while undergoing various processes such as curing of prepreg and copper pattern plating. We prepare specimens with various conditions and measure contours of each specimen and compute the residual stresses on deposited films using analytical solution to find the principle of bending. Core and prepreg in packaging substrate are made up of resin and bundles of fiber which exist orthogonally each other. Anisotropic material properties cause peculiar bending behavior of packaging substrate. We simulate the bending deflection with finite element method and verify the simulated deflection with measured data. The plating stress of electrodeposited copper is about 58 MPa. The curing stresses of solder resist and prepreg are about 13 MPa and 6.4 MPa respectively in room temperature.

• Composites Research
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• v.32 no.2
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• pp.113-119
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• 2019

The objective of this research is to study the mechanical and vibration characteristics of vibration damping aluminum panels for automotive parts. For this purpose, the test and simulation results of aluminum-resin hybrid materials and aluminum sheet materials were compared. Tensile strength and elastic modulus of the hybrid material were approximately 10% lower than aluminum sheet. Also, it was showed that the hybrid material have lower natural frequency than aluminum sheet, and it was confirmed that loss factor increases as the thickness of resin increases. Finally, it is confirmed that the test results and the analysis results are similar with each other and the performance prediction of the materials are possible by FEA.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.1063-1068
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• 2015

In this paper, we propose a collision simulation technique the evaluation of urban trains. We perform simulation that include a dynamics bogie model which represents the dynamic behavior of bogies and a finite-element model that can model crash behavior. We perform simulation in accordance with the 40-mm vertical offset head-on scenario for overriding the evaluation of the EU and domestic crashworthiness regulations. We evaluate the overriding by the vertical displacement of the wheelset using the overriding evaluation standard. Finally, if proposed simulation technique is applied, we can evaluate the overriding for urban-train crashworthiness regulations.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1550-1551
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• 2011

본 논문은 가정에서 사용하는 중 저압용 차단기의 차단 능력을 향상시키기 위한 방법에 초점을 두었다. MCCB의 차단 능력은 MCCB내부 부품들의 재료나 형상 그리고 배열 등 여러 요소에의해 결정된다. 특히 본 논문에서는 MCCB 그리드의 형상을 변화하여 소호시간을 단축하는 방법을 제안하였다. 사고에 의해 차단기가 작동하게 되면 차단기 내부 접점에서 Arc가 발생하게 된다. 이때 발생된 Arc에의한 2차 사고를 방지하기위해, Arc를 빠른 시간에 소호시켜야한다. Arc가 발생하게 되면 Arc내부는 도체처럼 전류가 흐르게 되는데 이 전류에 의해 소호부의 그리드를 따라 자속이 형성된다. 그리드의 형상에 따라 Arc 기둥 주변에 불균형적인 자속이 유도되고 이 불균형한 자속에 의해 Arc 주변에는 불균형한 로렌츠힘이 발생하여 일정 방향으로 힘이 작용하게 된다. 이때 발생한 로렌츠힘 에의해 Arc 기둥은 그리드 방향으로 소호된다. 분석을 위해 유한요소법을 이용한 시뮬레이션을 사용하였고 그리드 형상 변화를 통해 일정방향으로 로렌츠힘이 변화 전보다 증가한 결과를 얻었다. 본 논문의 내용에 추가로 그리드 내부에서 자속의 이동을 효율적으로 전달하기위한 방법을 연구하면 더 큰 로렌츠힘을 얻어 소호시간을 단축시킬 수 있을 것으로 사료된다.