• Tribology and Lubricants
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• v.17 no.1
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• pp.22-27
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• 2001

This paper presents an analysis of eccentricity ratio of rolling piston using mobility method which is a powerful tool for analyzing dynamically-loaded journal bearings with efficiency and applicability. And, we investigate influences of design parameters (discharge pressure, radial clearance, rotational velocity of shaft, and eccentricity of compressor) on bearing load and eccentricity ratio. The results show that the discharge pressure, radial clearance and rotational velocity of shaft have significant influence on eccentricity ratio, and the discharge pressure and eccentricity of compressor have influence on bearing load.

• Proceeding of EDISON Challenge
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• 2016.11a
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• pp.4-8
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• 2016

본 연구에서는 플라잉 디스크를 이용하여 회전 운동의 유무에 따른 공력특성의 변화를 비교 분석하였다. 회전 운동이 발생하면 표면에 비대칭적으로 압력이 분포하기 때문에 롤링 모멘트가 발생하고 마그너스 효과로 측력이 발생하고 피칭모멘트, 회전감쇠모멘트가 발생하고 롤 안정성이 증가한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4087-4092
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• 2014

The gangway connection of the articulated high speed railway vehicles (HSRV) is a double wrinkled rubber component to seal the air of the corridor under a range of angular deviations between the carriage end parts. From the results of non-linear structural analysis, one of the severe loading conditions for the connection is mixed mode (rolling+yawing) angular displacements while passing through the small-radius curved siding track of the HSRV depot. In this study, to ensure the safety enhancement of the component, the optimal design for the cross section of that was performed using the Solid Isotropic Material with Penalization (SIMP) method. Nonlinear finite element analysis confirmed that the decreases in the maximum principal strain of the optimized design under rolling and mixed modes are 68% and 39%, respectively, compared to the initial design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.649-654
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• 2010

A three-dimensional numerical study of the WIG-effect vehicle with a direct-underside-pressurization (DUP) system and a propeller is performed to analyze the aerodynamic forces and moments acting on the vehicle. The computational model includes all the compartments of a WIG-effect vehicle, including a propeller in the middle of the fuselage and an air chamber under the fuselage. The DUP system and propeller help considerably reduce the take-off speed and minimize the effect of the hump drag when the vehicle accelerates to take off on water. The airflow is accelerated by a propeller, and the air then enters the air chamber through a channel in the middle of the fuselage, this air helps increase the lift since the dynamic pressure of air is converted to static pressure. However, the air accelerated by the propeller produces excessive drag and creates yawing moment. It is found that the effect of yawing and rolling moments on static stability is negligible.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.711-720
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• 2002

A 3-D numerical model, which could demonstrate the static and dynamic responses of a curved bridge more precisely with the moving vehicles, was developed The dynamic response induced by the centrifugal rolling motion of vehicle was identified according to the variations of the partial grade and the curvature of the slab. Dynamic characteristics of the curved bridge with the moving vehicle were analyzed under the condition of support types and two different support systems. Parametric studies were conducted to compare the efficiency of load distribution in the curved bridge. In general, while the vehicle was crossing the curved bridge, negative reaction occurred in the inside of the girder. The final result showed that the support system located outside the girder was more advantageous than other systems, and the characteristics of load distributions differed from the others in the various conditions of support systems.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.727-730
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• 2011

본 논문에서는 3차원 자기부상열차에 대한 열차-가이드웨이 상호작용 해석기법을 제시하고자 한다. 수직 및 수평방향 변위, 피칭, 롤링 그리고 요잉에 대한 자유도를 각 보기와 차체에 대해 고려하여 총 25자 유도 자기부상열차에 대한 운동방정식을 유도하였다. 제어방식으로는 UTM01에 적용된 제어기법을 이용하였고, 궤도 틀림을 고려하기 위하여 미국 FRA에 적용하고 있는 궤도 불규칙성에 대한 밀도 스펙트럼 함수를 이용하여 조도를 생성하였다. 같은 조건하에 2차원 모델과 3차원 모델의 동적응답 결과를 비교하여 타당성을 확인하였고, 2차원 모델에서 고려할 수 없는 수평방향 조도를 도입하였을 때 수직방향 부상공극에는 두드러진 영향을 미치지 않았으나, 수평방향 부상변위에 있어서 중요하게 작용함을 확인하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.270-271
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• 2014

In spite of the methodology of evacuation process on vessels should be different comparing to the architecture on land, some have simulated the evacuations onboard ship with simulation tools which is developed only for the architecture. On this study, a vessel-oriented simulation tool is used to analyze the possibility of evacuation for a passenger ship. ${\cdots}$(중략)${\cdots}$ As a result of the simulation analysis, it is clear that the initial responding time and start-to-move time are so important, ${\cdots}$(중략)${\cdots}$.

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.221-229
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• 2013

To find the influence of incident angle of wave on the moment of 3 storied steel moment resisting frame which is placed on the concrete rectangular pontoon, the fluid dynamic analysis is carried out, varying the period of wave from 5 to 15 second by 2 seconds. As increasing incident angle of wave to longitudinal axis, the influence of RAO-rolling is increased. The moment of longitudinal frame is increased apparently by the wave pressure when the incident angle is $0^{\circ}$. And the moment of the frame due to the wave pressure is decreased as the incident angle is increased. But the moment of frame due to acceleration caused from pitching and rolling is increased. It is shown that the increased moment when incident angle is $90^{\circ}$ is much greater than that of incident angle $0^{\circ}$.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.797-803
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• 2010

A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of pre-stressed concrete (PSC) box girder bridges on the Korea high speed railway. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyze accurately and evaluate with in-depth parametric studies for dynamic responses of bridge due to the high speed railway vehicles. Three dimensional frame element is used to model the PSC box girder bridges, simply supported span lengths 40 m. The high-speed railway vehicles (K-TGV) including a locomotive are used as 38-degree of freedom system. Three displacements (vertical, lateral, and longitudinal) as well as three rotational components (pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic analysis by Runge-Kutta method which are able to analyze considering the dynamic impact factors are compared and contrasted. It is proposed as an empirical formula that the impact factors damaged the bridge load-carrying capacities occurs to the bride due to high-speed vehicle.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.377-380
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• 2000

도플러 로그용 센서를 이용하여 선박의 속도를 측정하면, 선박의 수평방향 이외의 움직임, 즉 핏칭이나 롤링 등에 의한 측정 속도의 부정확성이 문제가 된다. 본 연구에서는 이러한 핏칭과, 수중이라는 환경요인에 기인하여 다른 속도 측정용 센서들이 가지는 문제점을 극복할 수 있도록 진동판을 수평축에서 일정한 각을 가지도록 두 개 또는 네 개를 등 간격으로 배열한 야누스형 초음파 트랜스듀서를 개발하였다. 트랜스듀서 개발을 위하여 그 작동 구조를 해석하고 그에 따라 시제품을 제작한 후, 실험적인 성능 평가를 수행하였다. 시제작된 초음파 트랜스듀서는 지향성 및 감도가 우수하고, 대역폭이 넓은 성능을 가지고 있어, 실제 선박에 장착되어 도플러 로그용 초음파 트랜스듀서로 사용될 수 있는 가능성이 확인되었다.