• Journal of the KSME
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• v.28 no.6
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• pp.556-562
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• 1988

기계나 구조물의 수명을 결정하는 마멸은 물체간의 접촉으로 인한 것이고 마멸을 줄이기 위해 윤활이 발달되어 왔다. 여러 형태의 마멸을 해석하기 위해서 접촉역학의 이해는 필수적이라 할 수 있다. 하중과 운동 조건에 의한 다양한 접촉문제를 일반적으로 다루기 위해 접촉면을 중심 으로 한 접근 방법을 소개하였으며, 접촉문제의 특이성을 보이기 위해 마찰접촉문제 해석을 위한 한기법을 간단히 기술하였다. 고속 볼 베어링의 특성 해석과 접촉형상 최적설계를 통하여 광 범위한 접촉 역학의 적용의 일부를 소개하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1994.06b
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• pp.59-65
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• 1994

본 논문에서는 Tichy와 Connor의 와전류 마그네틱 베어링 해석을 토대로 모의실험을 하여 주요 설계변수를 찾았고 반발식 마그네틱 베어링을 실제 제작하여 실험적으로 설계변수들이 마그네틱 베어링의 부하특성에 미치는 영향을 해석함으로써 설계 필요한 자료를 정립하였고 기존의 이론적 해석을 검증하였다.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.513-518
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• 2003

The piston slap phenomenon is one of the major noise source of reciprocating compressors used in household electric appliances. In response to public demand, strict regulations are increasingly being imposed on the allowable noise level which is caused mostly by household electric appliances. In this paper, the dynamic behavior of suction and discharge valves are analytically calculated and the lubricant behavior between piston and cylinder are investigated using two-dimensional Reynolds equation. And the piston slap caused by the piston secondary motion is investigated by the finite element method.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.2
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• pp.1-12
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• 1998

The seismic behaviour of rotating machine-foundation systems subjected to six-component nonstationary earthquake ground accelerations is analyzed. The rotating machine-foundation system is idealized by using discs, rotating shaft, fluid-film journal bearings, pedestals, and space frame foundation. Thus, governing equations of motion for the rotating machine-foundation system are obtained by considering Gyroscopic effect, Coriolis effect, dynamic characteristics of fluid-film journal bearings, and translational and rotational motions of seismic rigid base. The influences due to Gyroscopic effects, Coriolis effects, and rotational motions of seismic base on the overall structural response are demonstrated by a numerical example. The results show that the inclusion of base rotations and Gyroscopic effects contributes significantly to the system response.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.291-296
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• 1999

This study presents a method for determining stiffness and damping coefficients of 30% U slider-air bearings by using perturbation method, and shows that this method is more accurate than steady state method according to the comparison of those with the modal analysis method. Through a generalized lubrication equation, which based on linealized Boltzmann equation, the static and dynamic pressure distributions are calculated by finite volume method.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1994.06a
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• pp.42-48
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• 1994

고압하에서 고속으로 작동하는 유압 피스톤 펌프(hydraulic piston pump) 또는 모터(motor) 등의 유압기계(hydrostatic machine)에서 피스톤과 실린더 사이의 간극(clearance)을 흐르는 유압유(hydraulic oil)의 유동에 관한 연구는 이러한 유압기계의 피스톤부 설계에서 특히 중요하다. 본 연구에서는 원통형 피스톤이 원통부와 테이퍼가 진 부분으로 나누어져 있는 복합(composite)형상의 피스톤에 대한 이론해석을 수행하여 피스톤의 형상이 유압 피스톤 펌프의 윤활성능에 미치는 영향을 조사하고자 한다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.219-226
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• 2000

Frictional performance of ring pack in internal engine is investigated by varying spatial dimensions of ring pack and operating speed. This investigation is performed with commercial software by Ricardo Consultant Engineers, Inc. which is now in wofdwide use in automobile industries. Among the ring performances, blow-by rate, axial ring motions and frictional behaviors of top and second rings are studies in our work.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.108-115
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• 2004

Experiment and analytical studies on the oil supply characteristics of scroll compressor have been presented. For a scroll compressor, oil supply system consisting of individual lubricating element such as pumps, oil passages and sliding surfaces has been modeled by equivalent electric circuit. By solving the closed network equations of the model, oil flow rates at various lubrication elements could be obtained. Total amount of the oil flow rate drawn into the shaft has been measured and compared reasonably well with the prediction by the numerical simulation.

• Tribology and Lubricants
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• v.20 no.1
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• pp.14-20
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• 2004

In high-speed gas-levitation applications a high compressibility number may bring a numerical difficulty in predicting generated pressure profiles accurately as it causes erroneous sudden pressure overshoot and oscillation in the trailing-edge. To treat the problem, in this study an exact exponential high-order shape function is introduced in the FE lubrication analyses. It is shown by various example applications that the high-order shape function scheme can successfully subdue undesired pressure overshoot and oscillation.

• Tribology and Lubricants
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• v.4 no.1
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• pp.74-80
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• 1988

For an analytic investigation on the dynamic behaviour of the eccentric piston and roller in the cylinder of small rotary vane compressors the hydrodynamic lubrication theory is opplied, analogous to the dynamic analysis of a engine bearing. An adequate modification of the equation of journal motion permits stable convergencies of the numeric calculation of the journal orbits. The increase of the outer diameter of the roller and the eccentricity of the piston gives a relative large decrease of the minimum gap between the roller and cylinder.