• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1437-1442
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• 2010

A slipper metal is used for power transmission in the aluminum hot rolling process. The slipper metal connects a spindle with a coupling. Therefore, if the slipper metal is seriously damaged, the spindle and the coupling will crash into each other. Therefore, preventing the destruction of the slipper metal is essential for ensuring a long mechanical life cycle. In this study, the structural analysis and optimal design of the slipper metal was carried out by finite element method for life extension of the slipper metal. To verify the interference of spindle assembly with modified slipper metal, a kinematics simulation was performed by applying various combinations of dynamic boundary conditions. As a result of structural analysis and optimal design of the slipper metal, the maximum stress of the modified slipper metal was lower than that of the initial model by 22%.

• Journal of Korea Water Resources Association
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• v.45 no.1
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• pp.39-52
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• 2012

Surface-subsurface interactions are an intrinsic component of the hydrologic response within a watershed. In general, these interactions are considered to be one of the most difficult areas of the discipline, particularly for the modeler who intends simulate the dynamic relations between these two major domains of the hydrological cycle. In essence, one major complexity is the spatial and temporal variations in the dynamically interacting system behavior. The proper simulation of these variations requires the need for providing an appropriate coupling mechanism between the surface and subsurface components of the system. In this study, an approach for modelling surface-subsurface flow and transport in a fully intergrated way is presented. The model uses the 2-dimensional diffusion wave equation for sheet surface water flow, and the Boussinesq equation with the Darcy's law and Dupuit-Forchheimer's assumption for variably saturated subsurface water flow. The coupled system of equations governing surface and subsurface flows is discretized using the finite volume method with central differencing in space and the Crank-Nicolson method in time. The interactions between surface and subsurface flows are considered mass balance based on the continuity conditions of pressure head and exchange flux. The major module consists of four sub-module (SUBFA, SFA, IA and NS module) is developed.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.156-156
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• 2015

도금 시뮬레이션의 목적은 실제 도금 상황에서의 전류밀도 및 도금두께 분포를 정확히 예측하여 최상의 품질과 최적의 공정조건을 확립하는데 있다. 제품에 부착된 도금 두께는 기하학적 배치에 의한 저항 (1차 전류밀도), 전기화학적 전하교환 반응에 의한 분극 (2차 전류밀도) 및 확산, 유동 등 도금물질의 공급에 의한 분극(3차 전류밀도)에 의해 결정이 된다. 현재까지 도금 시뮬레이션은 1차 전류밀도 예측에 대한 전자기학적 해석과 Butler-Volmer 식에 근거한 동력학적 전기화학 해석을 통해 2차 전류밀도 분포 해석만 이루어졌다. 즉, 도금 반응에 있어서 물질공급은 항상 일정하게 유지되는 것을 가정하고 해석을 하였다. 이는 3차 전류밀도 분포에 있어서 전극반응 계면에서의 유동에 의한 물질공급이 전기화학과는 다른 물리(physics) 영역이어서 이를 전기화학과 coupling 하는데 기술적으로 어렵기 때문이었다. 그러므로, 물질공급반응이 속도결정단계가 되는 고속도금이나 저농도 도금, gap, tranch, via hole, through hole 등의 도금의 경우에는 해석결과에 큰 오차를 야기하게 된다. 본 발표에서는 그동안 접근하지 못했던 전기도금 해석에 있어서 유동해석을 커플링하여 다중물리해석을 한 결과를 발표한다. 시편으로는 회전원판전극과 회전 헐셀을 이용하여 회전속도 (rpm)에 따른 전류밀도 및 도금두께 분포의 변화 거동을 예측하였다.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1031-1036
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• 2009

This study is intended to identify how quick disconnect coupling which connects with refrigerant piping of air-conditioner using R-22 refrigerant has effect on characteristics of flux. in the case where the air-conditioner installs utilizes quick disconnect coupling, COP has an effect on the quantity of cooling load because of changing flow rate and physical properties of refrigerant which flow into an entrance of expansion valve from coupling. Variation of flow rate can be regulated by changing expansion-contraction angle; $\alpha$ of an entrance and an exit of coupling. In this study, quick disconnect coupling is presented flow of coupling by using FLUENT as heat flow program. To have an effect on the expansion entrance valve, and by changing expansion-contraction angle; $\alpha$ of an entrance and an exit

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.545-545
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• 2016

전 세계적으로 여름철 국지성 집중호우 및 태풍으로 인한 피해가 빈번하게 발생하고 있으며, 산지가 많은 국내에서는 산지지역 뿐만 아니라 도심지에서의 토석류 피해 또한 급증하고 있다. 또한 2011년 7월 우면산 토석류, 춘천시 펜션 토석류 등 규모면에서 이전 보다 큰 토석류가 발생되고 있다. 이러한 토석류로 인한 피해를 줄이기 위해서는 토석류의 수치적 해석이 필요하며 현재 다양한 토석류 수치해석 모델을 이용하여 토석류를 분석하고 있다. 또한 토석류는 주로 강우로 인해 발생되기 때문에 토석류 해석을 위해선 강우-유출해석이 선행되어야 한다. 본 연구에서는 청송 풍력단지를 조성하는 면봉산 일대를 대상지역으로 선정하였다. 토석류를 유발시키는 강우를 해석하기 위해 분포형 강우-유출모형인 S-RAT모형을 사용하였으며, 토석류 해석을 위해 토석류 2차원 수치해석모형인 RAMMS모형을 사용하였다. 두 모형의 커플링을 통해 토석류 확산범위 및 유동심, 속도, 충격력을 산정하였다. 이를 통해 유역내 토석류 발생시 동일규모의 사방시설을 토석류 흐름구간에 설치하여 위치에 따른 저감효과를 분석하여 사방시설의 적정위치에 대한 분석을 실시하였다.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.75-85
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• 2003

Laboratory model blast and in-situ rock blast tests were conducted to determine blast-induced stress wave propagation characteristics under different explosive types, different loading conditions and different mediums. Dynamic numerical approaches were conducted under the same conditions as experimental tests. Stress magnitudes at mid-point between two blast holes which were detonated simultaneously increased up to two times those of single hole detonation. The rise time of maximum stress in a decoupled charge condition was delayed two times that of a fully charged condition. Dynamic numerical analysis showed almost similar results to blast test results, which verifies the effectiveness of numerical approaches fur optimizing the tunnel blast design. Dynamic numerical analysis was executed to evaluate rock behavior and damage of the contour hole, the sloping hole adjacent to the contour hole in the road tunnel blasting pattern. The rock damage zone of the sloping hole from the numerical analysis was larger than that of the contour hole. Damage in the sloping hole can be reduced by using lower density explosive, by applying decoupled charge, or by increasing distance between the sloping hole and the contour hole.

• Journal of Welding and Joining
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• v.16 no.6
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• pp.104-112
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• 1998

In the previous study, the countermeasure for welding deformation of bracket tilt is through up through experimental inspection for total process including welding process. For completeness of systematic examination of parts having sensitivity on welding deformation, the comparison and feedback between the result through simulation of welding process and experimental data is needed. In other words, it is necessary to control welding deformation that construct the prediction system for welding deformation through comparison and tuning with experimental data. In the present study, the application of FEA on welding process of bracket tilt with susceptibility to deformation is made and deformation behavior through change of welding sequence is focused on. It is used to improve the exactness of deformation analysis that three dimensional analysis for moving heat source, activated and deactivated bead element, and volume heat flux etc.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.674-679
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• 2005

Statistical Energy Analysis(SEA) has been considered as a Possible method for predicting responses of complex structures, especially at higher frequencies. In this paper, an SEA model of a vehicle was built using 138 energy storing subsystems connected together using 1019 Junctions. SEAM software program was used to build and calculate the model. To demonstrate the accuracy of the SEA model, predicted response levels were compared with measured levels. The source Input levels were measured at the engine mounting parts. There is good agreement between the estimated and the experimental results. This paper also identifies some dominant energy flow paths from sources. It is finally presented that the SEA model can optimize the design parameters of vehicles using model parameters and energy flow paths.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.744-745
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• 2015

This paper deals with magnetic characteristic analysis of axial flux permanent magnet coupling according to overload using analytical method. When magnet coupling has a slip, the eddy current induced in PM with conductivity. This eddy current make a distorted flux density. In this paper, we analyze the distorted flux density. The analytical results are validated extensively by comparing with 3d finite element analysis.

• Journal of the Korean Geotechnical Society
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• v.17 no.2
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• pp.31-39
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• 2001

본 연구에서는 수정 Cam Clay 모델과 혼합체 커플링 이론(coupled theory of mixtures)을 이용하여 피에조콘 관입시험을 해석하여 지반의 투수계수와 과잉간극수압의 정량적 관계를 고찰하였다. 본 연구의 이론적 해석 결과는 시험결과들과 비교하였으며 그 결과 피에조콘 관립 시험시 관측된 과잉간극수압은 지반의 투수계수가 $10^{-9}$m/sec에서 $10^{-6}$m/sec의 범위에서는 투수계수에 따라 피에조콘 관립 시험시 관측된 과잉간극수압이 현저하게 변하는 것으로 나타나 피에조콘 관입시험시 관측한 과잉간극수압을 이용하여 지반의 투수계수를 결정할 수 있음을 알 수 있었다. 또한 지반의 투수계수가 $10^{-9}$m/sec 이하에서는 지반이 거의 완전 비배수 상태에 가까운 거동을 나타내면, 투수계수가 $10^{-6}$m/sec 이상에서는 거의 완전 배수상태에 가까운 거동을 하는 것으로 나타났다.으로 나타났다.