• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.727-732
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• 2002

This study is to develop the model of alignment optimization based on design criteria by approaching through alignment of railway design and problems in economy, environment and technology for satisfying traffic volume of the main roads caused by economical and social developments. Now, Geographic Information System isn't applied when designing a present railway in home. And the design of railway alignment is still set on importance of transition curves and cant according to passenger comfort in abroad so tile study of railway alignment is at initiation phase so far. This paper is about decision of optimal alignment between two stations such as starting point and ending point automatically using GIS in optimization of railway alignment. A route between Sungsan city and Shinpung city is the training area and the study compared and evaluated optimal railway route by GIS automatically with present railway route designed. Present optimal fomulas was used in this study for optimization of railway alignment. The model of optimization of railway alignment was developed through topographical elements and it was mentioned by the model of road alignment because of the similarity in design of alignment. But the design of lateral track irregularities, cant fur passenger comfort and motion sickness fellowed by train rolling have to be considered more. Anyway, this study farmed the basis of using GIS and the study should be keep going on in the future.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.105-111
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• 2008

The clutch with torsional damper is installed on a passenger car with manual transmission, which not only transmits the power generated by engine to the transmission but also absorbs the shock and vibration from the engine. The torsional damper in the clutch dissipates the torsional vibration energy and eliminates the resonance in the driveline but high damping in the damper causes the increase of the vibration level which is against the comfort and durability. In this study, a dynamic model for the passenger car driveline with manual transmission was developed to investigate the vibration and the effects of characteristics of the driveline. With the dynamic model, the vibration characteristics of driveline were examined by the mode analysis and driving simulation, and the effects of hysteresis torque and spring constant were investigated. The vehicle tests with prototype torsional dampers were preformed and the test results showed good agreements with the simulation.

• 한국소음진동공학회논문집
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• 제19권3호
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• pp.243-250
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• 2009

The clutch with torsional damper is installed on a passenger car with manual transmission, which not only transmits the power generated by engine to the transmission but also absorbs the shock and vibration from the engine. The torsional damper in the clutch dissipates the torsional vibration energy and eliminates the resonance in the driveline but high damping in the damper causes the increase of the vibration level which is against the comfort and durability. In this study, a dynamic model for the passenger car driveline with manual transmission was developed to investigate the vibration and the effects of characteristics of the driveline. With the dynamic model, the vibration characteristics of driveline were examined by the mode analysis and driving simulation, and the effects of hysteresis torque and spring constant were investigated. The vehicle tests with prototype torsional dampers were preformed and the test results showed good agreements with the simulation.

• 한국강구조학회 논문집
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• 제28권3호
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• pp.163-171
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• 2016

철도교량의 경우 구조적인 안정성과 함께 주행 안전성과 승차감이 중요한 설계 고려 인자이다. 이 논문에서는 실제 통행열차에 의한 강박스거더 교량의 동적 응답이 계측되었고 확률적인 방법에 의해 분석되었다. 실험교량에 대해 측 경간 중앙에서의 처짐과 연직가속도가 약 한 달 동안 여러 가지 여객열차 및 화물열차에 대하여 수집되었다. 축중과 열차종류에 따른 영향이 분석되었으며 검벨확률지에 의한 100년, 200년 최대값이 예측되고 설계기준값과 비교되었다. 일부 가속도값을 제외하고 대부분의 결과는 설계기준값을 만족시켰으며 초과확률도 매우 낮았다. 철도교량의 사용성에 대한 종합적인 분석을 위하여 더 장기적인 계측과 다른 형식의 교량에 대한 분석이 필요하다.

• 한국소음진동공학회논문집
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• 제21권12호
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• pp.1159-1165
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• 2011

This paper presents ride comfort characteristics of a quarter-vehicle magneto-rheological(MR) suspension system with respect to different tire pressure. As a first step, controllable MR damper is designed and modeled based on both the optimized damping force levels and mechanical dimensions required for a commercial full-size passenger vehicle. Then, a quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of the quarter-vehicle MR suspension system. Finally, the ride comfort analysis with respect to different tire pressure is undertaken in time domain. In addition, a comparative result between controlled and uncontrolled is provided by presenting vertical RMS displacement.

• 한국철도학회논문집
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• 제14권6호
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• pp.495-500
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• 2011

철도차량의 승차감은 승객이 느끼는 감정이므로 물리적인 진동의 크기뿐만 아니라 인간의 감응도(느낌)도 고려하여야 하며, 이러한 진동에 대한 인간의 감응도를 나타낸 것이 주파수 보정곡선이다. 주파수 보정곡선은 라플라스 변환형태의 전달함수이기 때문에 이 전달함수를 직접 사용하여 시간 영역에서의 승차감의 평가가 불가능하다. 이를 해결하기 위해서 본 논문에서는 라플라스 변환형태의 전달함수를 시간 영역에서 사용할 수 있는 전달함수로 변환하는 방법을 제시하고 다양한 예제를 통해 이 방법에 대한 타당성을 입증하였다.

• 대한기계학회논문집A
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• 제38권9호
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• pp.979-988
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• 2014

자동차를 이용하는 시간이 늘어남에 따라 자동차 실내의 온열쾌적성에 대한 관심이 급증하고 있다. 그러나 아직까진 실제 자동차 중에서 공조시스템의 냉방성능은 자동차 제조사별로 온열쾌적성 지표를 통해 평가되지 않고, 실내의 공기 속도와 온도 등 열환경 기준에 의해 평가되고 있다. 또한 차 실내의 온열쾌적성을 수치해석으로 평가하는 경우 타당한 결과를 도출할 수 있는 수치기법에 대한 기준이 확립되지 않은 상황이다. 본 연구에서는 외부 열원을 모사하기 위하여 태양광선 추적모델을 사용하고, 공조시스템 작동 후 20 분까지 다양한 매개변수(공조시스템의 작동모드와 작동풍량, 인체모델 탑승조건)에 대한 자동차 실내의 온열쾌적성 평가를 수행하였다. 이를 통해 자동차 실내의 온열쾌적성 지표를 예측할 수 있는 평가모델을 도출하였다.

• 한국의류학회지
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• 제36권2호
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• pp.179-193
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• 2012

The development of modern transportation technology has required many people in spaces (such as vehicle seats, airports, and train stations) for long periods. The public seats provided in these places are manufactured in a standard size; however, fatigue sets in if the seats are unsuitable for the person's physical size. For this reason, this study developed an air cushion vest that would enhance the comfort of vehicle seats. Passengers in vehicles, trains, airplanes, and buses were observed and surveyed to understand the demand for seat comfort. Our analysis found that the greatest source of discomfort was involuntary nodding of the head while asleep and discomfort around the waist area. For this reason, the air cushion vest was designed to support the head and the waist. The neck cushion of this vest was designed to strengthen head support to counter forward nodding because existing commercial neck cushions had no support for forward nodding. For the waist cushion, at lumbar and below-lumbar parts were chosen as the key parts to be supported, the cushion was designed to contain air at those parts. To cover the embedded waist cushion, the vest was designed to be long. The closure was constructed with zippers from the neck to waistline, and with invisible snaps from the waistline to the hemline so that the wearer could open them easily while seated. A subjective comfort evaluation was conducted to verify the effectiveness of the developed vest. In the test, the developed cushions received a better evaluation than cushions currently available on the market. The volume of the vest could be adjusted by the inflow and outflow of air. It was proven that the vest was effective in terms of comfort and portability. This shows that the developed vest could enhance passenger comfort while sitting on vehicle seats.

• 한국철도학회논문집
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• 제13권6호
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• pp.552-558
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• 2010

철도차량의 승차감은 진동뿐만 아니라 소음, 냄새, 온도 등 많은 요인들에 의해 영향을 받지만 승객에 크게 영향을 주는 진동으로 평가하는 것이 일반적이다. 승차감은 승객이 느끼는 감정이므로 물리적인 가속도의 크기뿐만 아니라 진동에 대한 인간의 감응도(느낌)도 고려하여야 한다. 이러한 진동에 대한 인간의 감응도를 나타낸 것이 주파수 보정곡선이다. 따라서, 철도 차량의 승차감 평가에는 인간의 감응도가 고려된 주파수 보정 가속도를 필요로 한다. 철도차량의 승차감 평가는 많은 규격에 규정되어 있으나, 각각의 규격에 따라 서로 다른 주파수 보정 곡선을 제시하고 있다. 본 논문에서는 국제철도협회, 유럽표준위원회, 국제표준위원회에서 규정한 주파수 보정곡선에 대해 분석하고 그 차이점을 고찰한다. 또한, 주파수 보정곡선의 차이가 고속철도 차량의 승차감 평가에 미치는 영향을 실제의 시운전 시험을 통해 분석하고자 한다.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.121-128
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• 2005

In most researches on the ride comfort analysis of passenger vehicles, the flexibility of the vehicle body has been not considered as an important factor, because the resonance frequencies of the vehicle body related to pitching, yawing and rolling motions are below 10Hz while the resonance frequencies of the vehicle body related to the flexibility are above 20Hz approximately. Nevertheless, the paper shows that the consideration of the local flexibility (or local stiffness) of the 4 corners on which shock absorbers are mounted influences the ride comfort. A simple beam model is devised to qualitatively examine the effect of the change of the local stiffness of the vehicle body on the ride comfort. Based on the results obtained from the analysis of the one-dimensional model, multi-body dynamic analysis considering the flexibility of the vehicle body is performed using ADAMS and MSC/NASTRAN. Natural frequencies and mode shapes computed by MSC/NASTRAN are used as input data for multi-body dynamic analysis in ADAMS. Through simulations using ADAMS, it has been found that the ride comfort can be improved by changing the local stiffness of the vehicle body and that the simulation results agree with experiment results.