• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2600-2608
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• 2011

The dynamic stability of railway vehicle has been one of the important issues in railway safety. The dynamic simulator has been used in the study about the dynamic stability of railway vehicle and wheel/rail interface. Especially, a small scale simulator has been widely used in the fundamental study in the laboratory instead of full scale roller rig which is not cost effective and inconvenient to achieve diverse design parameters. But the technique for the design of the small scale simulator for the fundamental study about the dynamic characteristics of the wheel-rail system and the bogie system has not been well developed in Korea. Therefore, the research about the development of the small scale simulator and the bogie has been conducted. As this paper, To predict the dynamic behavior of railway vehicle, we studied running stability test of 1/5 scaled bogie that similarity laws is applied using small scale derailment simulator. For the operation of the small scale derailment simulator, it is required to investigate the performance and characteristics of the system. This could be achieved by a comparative study between an analysis and an experiment. This paper presented the analytical model which could be used for verifying of the test results and understanding of the physical behavior of the dynamic system comprising the small scale bogie and the simulator.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.848-853
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• 2005

The objective of this paper is to address to the providing an adequate noise and vibration solution, required for High Speed Rail while maintaining the stability criteria of the ChonAn station structure, the first constructed in Korean High Speed Railway. The significant acoustic pressure level will be induced by the high speed trains passing-by. Therefore, the high level study of this case is necessary. The acoustic pressure level of 85 dB(A) inside the ChonAn station is expected, and the spaces below concrete slab are not suitable for commercial purpose, thus installation of filtering systems (spring boxes containing viscous dampers, ballast mats and acoustic shield) are provided to reduce the effect of the noise and vibration to acceptable level of 55 dB(A). But, a major drawback of application of the previously conducted experimental results was that the actual effect of installation of filtering system was never been validated. Therefore, the acquisition of noise and vibration on the present structure were obtained and compared to the computer simulations. These predicted the behavior of the station reasonably well. Also, the installation of filtering systems gave the superior reduction on noise and vibration. This application is successfully adapted without scarifying stability criteria related to the structural stability including excessive deformations or displacements. Three traffic operation safety limits: deck vertical acceleration, deflection of the structure, and longitudinal displacement of the slab were satisfactory.

• 한국강구조학회 논문집
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• 제17권5호통권78호
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• pp.519-526
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• 2005

혹서기에 레일의 높은 온도 상승(최대 $60^{\circ}C$)으로 인해 장대레일 궤도에는 매우 큰 압축력이 작용하게 된다. 이러한 압축력은 장대레일 궤도의 좌굴을 발생시키기도 한다. 본 연구에서는 장대레일 궤도의 좌굴에 영향을 미치는 많은 요소들 중에서 도상 횡저항력 그리고 도상 종저항력이 궤도 좌굴에 미치는 영향을 파악하기 위한 연구를 수행하였다. 또한 줄틀림과 궤간틀림의 민감도를 분석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1657-1659
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• 2005

Test track of the Light Rail Transit(LRT system was developed and organically combined with technologies of power supply system, signal communication system and track structure The purpose of the test track is a acquiring of reliability and stability through a sufficient performance test Therefore, this paper draws up ail management plans for tests of the LRT system

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.973-978
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• 2008

This study concerned on the critical speed due to hunting and snake motion train to ensure the stability. First, the critical speed was calculated by using a numerical model, and calculated the critical speed of the vehicle through the simulation with the use of ADAMS/RAII. Also, the snake motion was confirmed through a modal analysis and running simulation. The calculated results, show that the rail irregularity becomes the influential factors of the stability since it is the direct source of excitation of the vehicle.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.864-866
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• 2003

In this paper, the improvement of control performance for a magnetic levitation system is presented. The model of a single-magnet system with rail is derived. As a conventional controller, PID controller is designed and implemented. This controller has a narrow stability margin due to low-order controller structure so that it cause unstability for a flexible rail. So to improve the control performance and stability margin, a robust controller as a new controller is designed and implemented using a VME-based digital controller. As a result, the controller performance of the new designed controller is better than that of the conventional controller.

• Geomechanics and Engineering
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• 제36권5호
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• pp.417-426
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• 2024

Shield tunneling method is widely used to build tunnels in complex geological environment. Stability control of tunnel face is the key to the safety of projects. To improve the excavation efficiency or perform equipment maintenance, the excavation chamber sometimes is not fully filled with support medium, which can reduce the load and increase tunneling speed while easily lead to ground collapse. Due to the high risk of the face failure under non-fully support mode, the tunnel face stability should be carefully evaluated. Whether compressive air is required for compensation and how much air pressure should be provided need to be determined accurately. Based on the upper bound theorem of limit analysis, a non-fully support rotational failure model is developed in this study. The failure mechanism of the model is verified by numerical simulation. It shows that increasing the density of supporting medium could significantly improve the stability of tunnel face while the increase of tunnel diameter would be unfavorable for the face stability. The critical support ratio is used to evaluate the face failure under the nonfully support mode, which could be an important index to determine whether the specific unsupported height could be allowed during shield tunneling. To avoid of face failure under the non-fully support mode, several charts are provided for the assessment of compressed air pressure, which could help engineers to determine the required air pressure for face stability.

• 한국방재학회 논문집
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• 제4권1호
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• pp.25-31
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• 2004

강우침투는 철도성토사면의 불안정성을 유발하는 요인으로 작용하여 때때로 파괴의 결과로 나타나게 된다. 강우량과 철도성토사면 안정성과의 기본적인 상관성이 강우에 의한 성토사면의 불안정성을 분석하여 제안되었다. 사면내부로의 강우침투속도를 규명하기 위하여 실내시험을 수행하였으며, 강우침투실험결과에서 강우침투량은 강우침투속도가 사면경사에 의해 지배되기 때문에 저수지 등의 경우에 있어서의 침투와는 상당히 다르다는 것을 알 수 있었다. 이와 같은 견과에 근거하여 강우의 경계조건을 변화시켜 적용한 후, 다양한 수치해석을 수행하였다. 이를 통해 강우시 철도 성토사면의 전단강도, 포화도 그리고 간극수압의 변화를 예측할 수 있었으며, 철도사면의 안전율이 강우량-강우지수의 함수로서 표현될 수 있었다. 따라서 이 강우지수가 강우시 열차운전규제기준을 설정하기 위해 유용함을 밝혔다.

• 한국소음진동공학회논문집
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• 제22권4호
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• pp.307-317
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• 2012

The LRT(light rail transit) system, which has medium transport capacity between subway and bus is an advanced transportation system. It has many benefits like chap construction and operational cost down through driverless and flexible route planning. The rubber tired AGT(K-AGT) is a kind of LRT, which has rubber wheels and side guides. The side guides has many advantages, but brings vibration and noise problems from the friction between the guide rail and the wheels. This is the major source for the of passengers' discomfort. The purpose of this paper is to analyze dynamic characteries and running stability of the rubber tired AGT localization bogie if the AGT's speed is increased from 70 km/h to 80 km/h. The current design parameters of bogie suspension, as it is designed, was examined to satisfy the comfort index of the railway vehicle in performance test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.310-312
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• 2006

Maglev using EMS becomes unstable by unexpected big air-gap disturbance. The main causes of the unexpected air-gap disturbance are step-wise rail joint and large distance between rail splices. For the stable operation of the Maglev, the conventional system uses the threshold method, which selects one gap sensor among two gap sensors installed on the magnet to read the gap between magnet and guide rail. But the threshold method with a wide bandwidth makes the discontinuous air-gap signal at the rail joints because of the offset in air gap sensors and/or the step-wise rail joins. Further more, in the case of the one with a narrow bend-width, it makes Maglev system unstable because of frequent alternation. In this paper, a new method using fuzzy rule to reduce air-gap disturbances proposed to improve the stability of Maglev system. It treats the air-gap signal from dual gap sensors effectively to make continuous signal without air gap disturbance. Simulation and experiment results proved that the proposed scheme was effective to reduce air-gap disturbance from dual gap sensors in rail joints.