• 문화기술의 융합
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• 제8권5호
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• pp.547-552
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• 2022

본 연구에서는 궤도틀림이 차륜-레일 상호작용력에 미치는 영향을 분석하고 이를 바탕으로 궤도틀림을 관리할 수 있는 하중기반의 궤도틀림 분석기법을 제안하였다. 도시철도 침목플로팅궤도와 직결도상 접속구간에서 발생된 고저틀림 측정결과를 이용하여 고저틀림이 차륜-레일 상호작용력(동적윤중)과 레일의 진동가속도에 미치는 영향을 해석적으로 분석하였다. 직결궤도 총 4개소를 대상으로 부분적으로 직결궤도를 포함한 침목플로팅궤도 구간과 전, 후 인접 침목플로팅궤도 구간으로 구분하여 고저틀림을 비교, 분석하였다. 분석결과, 직결궤도를 포함한 구간이 침목플로팅궤도 보다 궤도틀림이 크게 나타났다. 고저틀림 데이터를 적용한 차륜-레일 상호작용력 분석결과, 거리에 비해 상대 변위차가 큰 구간에서 차륜-레일 상호작용력과 레일가속도가 증가하는 것으로 분석되었다. 반면 고저틀림 데이터의주기와 틀림량(변위)이 일정한 구간의 경우 차륜-레일 상호작용력과 레일가속도가 상대적으로 작게 나타났다. 따라서고저틀림의 주기가 짧고 상대변위차가 클수록 차륜-레일 상호작용력 측면에서 불리한 것으로 분석되었다. 본 연구에서는 궤도틀림 측정데이터를 이용한 차륜-레일 상호작용 해석을 통해 차륜-레일의 상호작용력을 바탕으로한 하중기반의 궤도틀림 분석기법 적용방안을 제시하였다.

• 한국정밀공학회지
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• 제14권4호
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• pp.22-29
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• 1997

This paper presents results on dynamic analysis of the missile initial motion arising from the missile detent force. Using ADAMS (Automatic Dynamic Analysis of Mechanical Syatem) software, a non- linear46-DOF (Degree of Freedom) model is developed for the launcher system including missile and lunch tube contact problem. From the dynamic analysis, it is found that initial angular velocity of the missile incre- ases when the missile detent force increases and also when rocket exhaust plume is taken into account. To achieve the missile launching stability, it needs to reduce the missile initial detent force and exhaust plume area of the lancher. Results of the dynamic analysis on the system natural frequency agree well with those obtained from experimental modal tests. The overall results suggest that the proposed method is a useful tool for prediction of initial missile stability as well as design of the missile launcher system.

• 한국초전도ㆍ저온공학회논문지
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• 제15권3호
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• pp.13-19
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• 2013

Superconducting field coils using a high-temperature superconducting (HTS) wires with high current density generate high magnetic field of 2 to 5 [T] and electromagnetic force (Lorentz force) acting on the superconducting field coils also become a very strong from the point of view of a mechanical characteristics. Because mechanical stress caused by these powerful electromagnetic force is one of the factors which worsens the critical current performance and structural characteristics of HTS wire, the mechanical stress analysis should be performed when designing the superconducting field coils. In this paper, as part of structural design of superconducting field coils for 17 MW class superconducting ship propulsion motor, mechanical stress acting on the superconducting field coils was analyzed and structural safety was also determined by the coupling analysis system that is consists of commercial electromagnetic field analysis program and structural analysis program.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.1017-1022
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• 1996

This paper presents results of dynamic analysis of the missile initial motion arising from the missile detent force. Using ADAMS (Automatic Dynamic Analysis of Mechanical System) software, a non-linear 46-DOF (Degree of Freedom) model is developed for the launcher system including missile and launch tube contact problem. From the dynamic analysis, it is found that initial angular velocity of the missile increases when the missile detent force increases (more than 18 g) and also rocket exhaust plume is taken into account. To achieve the missile launching s ability, it needs to reduce the missile initial detent force and exhaust plume area of the launcher. Results of the dynamic analysis on the system natural frequency agree well with those obtained from experimental modal tests. The overall results suggest that the proposed method is a useful tool for prediction of initial missile stability as well as d :sign of the missile launcher system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.890-895
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• 2005

This paper presents the dynamic analysis of a cantilever beam undertaking impulsive force that undergoes rigid body motion. The transient response of the beam induced by the impulsive force and the rigid body motion is calculated based on hybrid deformation variable modeling method by applying the Rayleigh-Ritz assumed mode method. The stiffness variation effect caused by the rigid body motion is considered in this modeling. The effects of the impulsive force position and the angular velocity on the transient responses of the beam are investigated through numerical studies.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.393-396
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• 2003

A systematic investigation for the process design in deep drawing is necessary to improve the quality of drawn cups. This study concentrates mainly on the influence of process design strategy on the product quality. Several types of process design were chosen from initial blank of 100mm in diameter to make final cup of 50mm in diameter. Forming analysis are carried out to find out optimal design in terms of drawing force. We assume that the case which shows minimum drawing force in the subsequent operations is the best case. Through experiments it is found that the case which shows minimum drawing force also results in minimum drawing force and better product quality than other case. Thus, it is shown that this design strategy is very effective in the improvement of quality in drawn cups.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.94-103
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• 2011

This paper presents a novel bearingless switched reluctance motor (BLSRM) with decoupled torque and suspending stator poles. BLSRM is different from conventional bearingless switched reluctance motors (SRMs) because its suspending poles are separated from the torque poles. Perpendicularly placed suspending poles are designed to produce a continuous radial force to suspend the rotor. Due to the independent suspending and torque poles, BLSRM produces a suspending force with excellent linearity according to the rotor position and independent characteristics of the torque current. The air-gap is easier to control than in conventional SRMs with their linear and independent characteristics. Furthermore, to verify the proposed structure, a mathematical model for the suspending force is derived. Finite element analysis is also employed to compare BLSRM and conventional SRMs expressions of suspending force. A prototype motoris designed and manufactured to verify the effectiveness of the proposed bearingless structure.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.131-137
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• 2003

Proper door effort, required force to open or close a vehicle door, is an essential door design factor for the safety of passengers and pedestrians. Section shape of the door checker arm is the most influential design parameter for achieving a door effort design target. In this research. an analysis procedure to predict door effort using a simplified plane strain finite element model wes investigated for two passenger cars, for which mechanism of checker systems were: different. The variation of checker arm force to be required during moving on arm in opening and closing direction was estimated through analysis, and the result was transformed to the door effort with respect to door opening angle by considering door characteristics. Also, the self·closing force due to door weight was theoretically calculated and added to the door effort from checker arm force. Finally the estimated results of door effort were compared with test results.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.1-4
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• 2011

The full spade rudder for the high speed has advantage to prevent gap cavitation of the rudder. DSME has developed the full spade rudder and GL has carried out CFD analysis and FE analysis to confirm strength and fatigue for DSME and Owner. Necessarily, it needs to compare rudder torque & rudder force between CFD, FE analysis and full scale measurement. This report introduces the measurement method and application of strain gauge for measuring the rudder torque and rudder force for the 8,400 TEU container ship.

• 한국과학교육학회지
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• 제7권2호
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• pp.61-70
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• 1987

This paper was made for the purpose of examining middle school student's conception about force and motion. Using questionaire method. this research was executed to 180 students at a middle school in Seoul. Questions were as following; 3 questions about relation of the direction of force and that of motion in case of throwing a ball up, 2 questions about parabolic motion. 1 question about inertia. and 1 question about action and reaction. The way of answering was both selecting and explaining the students' thought about questions. Network analysis was used for analyzing students' various responses. Through the analysis. some types of students' thought were revealed. As a result the representation of their response was motion implies force which had been discovered by earlier researchers. Even though students had learned about force and motion in the classroom. their ideas were unchanged or even reinforced wrongly in some case.