• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1057-1062
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• 2007

The purpose of this study is to find out design parameters of vibrating screen, such as particles motion, specific gravity, shape, and kinetic friction. In order to approach this problem, four materials of construction wastes, wood, styrofoam, concrete, and sand are used for dynamic modeling. To present friction between the particles material and tilt plates material, these particles model is applied in order to verify effectively. Generally, the vibrating screen is composed of three assemblies such as screen, wastes guide, supported of screen. This model regards vibrator as system of screen fixed tilt plates. The model is analyzed to present what kind of particles motion while the system is vibrating. and this vibration system has been implemented in a ADAMS dynamaic program. This modeling is consist of dynamic model separation state on particle size. This study make good technique to verify in theory.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.10
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• pp.1034-1042
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• 2009

In this paper, the magic formula model was applied for a friction damper in a drum-type washing machine. To describe characteristics of the hysteretic damping force, Physical tests were first carried out to get experimental results using an MTS machine. Then, parameters for the magic formula model were determined from the experimental curves. The ADAMS and MATLAB programs were used for the multibody modeling of the damper and process for parameter identification. The model of drum-type washing machine was applied for a dynamic model of friction damper, in which the accuracy of the proposed damper model was verified.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1996.11a
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• pp.15-24
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• 1996

로켓모타의 연소관은 구조적인 편의성 및 경량화를 위하여 도옴-실린더부와 실린더-노즐부에 나사체결방법을 많이 적용하고 있는데, 나사의 골부위에 집중응력이 발생하여 인장강도를 넘는 응력이 발생하는 경우가 있다. 본 연구에서는 나사의 골부위의 응력수준을 좀 더 정확히 예측하기 위하여 나사체결시 작용하는 조립 토오크에 의한 초기하중을 고려한 구조해석을 수행하였으며, 나사부위에 발생하는 응력이 항복강도를 초과하므로 정확한 해석을 위하여 탄소성해석을 수행하였다. 조립 토오크에 의한 초기하중은 나사체결 멈춤부에 음(-)의 접촉 간극을 부여하여 모델링하였으며, 조립 토오크의 크기는 나사체결 근접부에서 변형률을 측정하여 모사하였다. 해석결과 초기하중을 고려하여 구조해석을 수행하면 최대예상 작동압력에서 초기하중의 영향은 거의 나타나지 않았으며, 마찰계수를 감소시키면 최대응력이 감소하여 구조적 안전성이 증가할 것으로 판단된다.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.28-35
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• 2002

This paper deals with kinematic modeling of a car-like planar mobile robot consisting of four conventional fixed wheels attached on two parallel axles. The kinematic model of such a mobile robot requires the description of skidding and sliding frictional motion. Previous kinematic model proposed by Muir and Newman$^{[1]}$ does not include such frictional motions. Thus, does it result in least square solution in estimating a sensed forward velocity solution. A modified kinematic model is proposed by incorporating transnational friction motion into the original algorithm. It is shown that transnational friction motions should be included into kinematic model of the mobile robot to represent its real physical motion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.419-424
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• 1996

As track density increases, the effects of nonlinearity in pivot bearing of hard disk drive on the servo performance are becoming more important in considering the range of inertia force and the input torque during settling and tracking mode. Recently, an increasing attention is given to more precise experimental observations and modelings of pivot nonlinearity for achieving higher performance of servo control. In this paper, we propose a new model that shows an improved prediction of the pivot nonlinearity than existing preload-plus-two-slope model at matching simulations and experimental results in both time and frequency domains. Experimental measurements are carried out to validate and identify the specific nonlinearity presents in the pivot bearing when its in fine motion. Using the experimental results new model along with the existing one are characterized and compared for relevancies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.11
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• pp.1085-1089
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• 2017

Juryeonggu is a cuboctahedral die that was used during the Silla period in ancient Korea. This cuboctahedral die consists of two different penal servitudes of 14 sides; however, its equal probability distribution enables it to be used as a die. In this paper, a precise cuboctahedral die, Juryeonggu, was manufactured, and its probability was measured through experiments. Next, the probability was verified through Multibody-dynamics (MBD) modeling and analysis, and the effect of the coefficient of friction on the probability distribution was studied.

• Nuclear Engineering and Technology
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• v.27 no.1
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• pp.133-140
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• 1995

본 논문은 가압경수형 원자력발전소내 비고정식 고밀도 사용후 핵연료 저장대의 지진해석을 수행하기 위해 현재 사용되고 있는 해석방법을 검토하고 있다. 석기서는 영광 3, 4호기 및 울진 3, 4호기 계통설계 경험을 통해 한국원자력 연구소가 보유하게 된 해석 기술을 근거로 하여 해석과정과 모델방법 등을 논의하였다. 비고정식 사용후 핵연료 저장대의 해석은 냉각수에 의한 수력학적 커플링 효과, 핵연료와 중성자 흡수체 및 저장대 구조물 사이의 간극에 의한 충돌, 마찰효과, 그리고 강체 미끌어짐 및 기울어짐 등의 복잡한 현상들을 고려해야 한다. 이러한 모델링 변수들에 대하여 현재의 방법과 규제기관의 추천사항을 비교, 검토하였으며 해석방법 개선 및 최근의 기술적 관심사항들에 대하여 논의하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.3084-3090
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• 1994

A new flow model is developed for the analysis of compression molding of sheet molding compounds(SMC) and penalty finite element formulation is presented to predict flow front progressions more accurately. In this model SMC is assumed nonisothermal fluid, which has different viscosities in extension and in shear. The flow is allowed to slip at the mold and is resisted by friction force which is proportional to the relative velocity at mold surface. For the verification of the model, the press force and flow patterns are compared with those of experiments and available results by other works in this field. It is also demonstrated, using the computational procedure described and the proposed model, that optimal initial charge shapes for the filling can be effectively computed.

• Journal of the Korean Professional Engineers Association
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• v.46 no.2
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• pp.36-43
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• 2013

풍력발전단지의 운영으로 인한 주된 소음은 풍력발전기의 고체음과 바람을 가르는 마찰 기류음으로 대별된다. 본 원고(原稿)에서는 소음레벨을($L_{PAN}$) 정량적으로 예측, 계산하는데 이용하는 소음예측식을 풍력발전에 맞게 이론적으로 해석하고, 소음발생원의 특성을 분석하여 운영시 소음영향 및 저감방안을 검토하였다. 풍력발전 사업계획시 소음예측식과 소음모델링(CadnaA version4.1, SoundPLAN version7.0 해석 결과 등)을 이용한 예측결과를 서로 비교 검토하고, 운영시(사후환경영향조사 등) 실제 소음레벨과 소음예측 결과를 서로 비교분석하여 데이터를 축척하길 바란다. 제언한 소음저감방안이 불충분한 경우 발전기의 배치와 설치간격, 발전기종 및 발전용량, 설치장소의 재선정 등을 추가 검토할 필요가 있다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.1
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• pp.27-33
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• 2005

In this study, the process parameters in ceramics powder compaction are optimized for getting high relative densities of ceramic products. To find optimized parameters, the analytic models of powder compaction are firstly prepared by 2-dimensional rod arrays with random green densities using a quasi-random multiparticle array. Then, using finite element method, the changes in relative densities are analyzed by varying the size of Al₂O₃ particle, the amplitude of cyclic compaction, and the coefficient of friction, which influence the relative density in cyclic compactions. After the analytic function of relative density associated process parameters are formulated by aid of the response surface method, the optimal conditions in powder compaction process are found by the grid search method. When the particle size of Al₂O₃ is 22.5 ㎛, the optimal parameters for the amplitude of cyclic compaction and the coefficient of friction are 75 MPa and 0.1103, respectively. The maximum relative density is 0.9390.