• 제목, 요약, 키워드: Rail Stability

검색결과 218건 처리시간 0.036초

궤도 안정성에 대한 장대레일과 체결구의 민감도 (Sensitivity of the Continuous Welded Rail and the Fastener on the Track Stability)

  • 한상윤;박남회;임남형;강영종
    • 대한토목학회논문집
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    • v.26 no.4A
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    • pp.719-726
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    • 2006
  • 전세계적으로 널리 사용되고 있는 장대레일 궤도는 유지 보수 비용을 절감시키고, 궤도구성요소들의 수명이 길어진다는 장점을 가지고 있다. 그러나, 혹서기에 레일의 높은 온도 상승으로 인해 장대레일 궤도에는 매우 큰 압축력이 작용하게 되고, 이는 장대레일 궤도의 장출(좌굴)을 발생시켜 열차의 탈선으로 인한 사고로 이어진다. 본 연구에서는 장대레일 궤도의 좌굴에 많은 영향을 주는 궤도의 구성요소들 중에서 레일의 단면적과 단면2차모멘트 그리고 체결구의 파손과 병진 및 회전방향의 강성이 장대레일 궤도의 좌굴에 미치는 민감도를 파악하였다.

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소형무인경전철 레일이음매의 적정 간격 산정 연구 (A Study on Optimum Spacing of Rail Joint for Personal Rapid Transit(PRT) Track System)

  • 최정열;김필수;정지승
    • 문화기술의 융합
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    • v.4 no.3
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    • pp.213-220
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    • 2018
  • 본 연구에서는 레일이음매를 배제할 수 없는 각관형 레일을 사용하는 PRT궤도구조를 대상으로 레일이음매 설치위치 및 간격을 최적화함으로써 레일이음매부의 충격 및 승차감 저하 현상을 최소화 하고자 수치해석 및 현장측정을 통해 열차주행 시 PRT 차량의 실 열차속도를 고려한 궤도 구조의 일반부 및 레일이음매부의 동적거동을 파악하여 레일이음매의 적정간격을 산정하였다.

Rail-Joint에서 퍼지룰을 기반으로하는 공극신호처리법 (Air-Gap Signal Treatment based Fuzzy Rule in Rail-Joint)

  • 성호경;조정민;이종무;배덕권;김봉섭;신병천
    • 대한전기학회:학술대회논문집
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    • pp.1071-1072
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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.

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강우시 철도성토사면의 열차운전규제기준에 관한 연구 (A Study on the rail-transport operation control for railway embankment under rainfall)

  • 김현기;박영곤;신민호;김수삼
    • 한국철도학회:학술대회논문집
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    • pp.514-519
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    • 2001
  • There are a close relationship between natural disasters and train safety. So it is very important to guaranty train safety using reasonable rail-transport operation control against disasters. Therefore, based on the past record of rainfall at failure, rail-transport operation control for railway embankment under rainfall was set up. After slope check list at home and abroad had been analyzed, new slope check list was suggested and site investigations were carried out using this check list. In order to evaluate the stability of railway slopes under rainfall, explanatory variables and subordinate variables were selected for multi-variate analysis and critical rainfall was defined by statistical process. Rail-transport operation control including regional and geological properties was suggested by analyzing the critical rainfall and rail-transport operation control in other country, and this will be a good tool to control train speed under rainfall and to secure train safety.

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On bending, buckling and vibration of graphene nanosheets based on the nonlocal theory

  • Liu, Jinjian;Chen, Ling;Xie, Feng;Fan, Xueliang;Li, Cheng
    • Smart Structures and Systems
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    • v.17 no.2
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    • pp.257-274
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    • 2016
  • The nonlocal static bending, buckling, free and forced vibrations of graphene nanosheets are examined based on the Kirchhoff plate theory and Taylor expansion approach. The nonlocal nanoplate model incorporates the length scale parameter which can capture the small scale effect. The governing equations are derived using Hamilton's principle and the Navier-type solution is developed for simply-supported graphene nanosheets. The analytical results are proposed for deflection, natural frequency, amplitude of forced vibration and buckling load. Moreover, the effects of nonlocal parameter, half wave number and three-dimensional sizes on the static, dynamic and stability responses of the graphene nanosheets are discussed. Some illustrative examples are also addressed to verify the present model, methodology and solution. The results show that the new nanoplate model produces larger deflection, smaller circular frequencies, amplitude and buckling load compared with the classical model.

KR60 레일의 미세조직과 기계적 물성 평가 (Investigation of Microstructure and Mechanical Properties of KR60 Rail)

  • 최욱진;조희재;윤경민;민경환;임남형;이수열
    • 한국재료학회지
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    • v.27 no.12
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    • pp.652-657
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    • 2017
  • The use of continuous welded rail is increasing because of its many advantages, including vibration reduction, enhanced driving stability, and maintenance cost savings. In this work, two different types of continuous welded rails were examined to determine the influence of repeated wheel-rail contact on the crystal structure, microstructure and mechanical properties of the rails. The crystal structure was determined by x-ray diffraction, and the microstructure was examined using optical microscopy and scanning electron microscopy. Tensile and microhardness tests were conducted to examine the mechanical behaviors of prepared specimens taken from different positions in the cross section of both newly manufactured rail and worn rail. Analysis revealed that both the new and worn rail had a mixed microstructure consisting of ferrite and pearlite. The specimens from the top position of each rail exhibited decreased lamella spacing of the pearlite and increased yield strength, ultimate tensile strength and hardness, as compared with those from other positions of the rail. It is thought that the enhanced mechanical property on the top position of the worn rail might be explained by a mixed effect resulting from a directional microstructure, the decreased lamella spacing of pearlite, and work hardening by the repeated wheel-rail contact stress.

KTX 후미 차량의 주행 안정성 해석 (Running Stability Analysis on the Tail Car of KTX)

  • 이승일;최연선
    • 한국철도학회:학술대회논문집
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    • pp.350-355
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    • 2005
  • The running stability and safety of a railway vehicle depends on the design characteristics and the contact condition between wheel and rail. In this paper, numerical simulations using ANSYS and ADAMS were done on the basis of the experimental observations. The results show that 0.6 Hz of the tail car motion is due to the natural mode of car combination of the KTX. The effects of the conicity of wheel and the lateral stiffness of the secondary suspension on the running stability were analyzed numerically using ADAMS/RAIL. The results also show 0.6 Hz as like the experimental observations. And the adoption of the wheel of GV40(${\lambda}=0.025$) brought the sway motion at the tail cars, but XP55(${\lambda}=0.055$) did not when the secondary lateral stiffness of the KTX was greater than 0.3 MN/m.

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비평면 지면효과를 받는 날개들의 종방향 정안정성 (Longitudinal Static Stability of Wings Flying Over Nonplanar Ground Surfaces)

  • 김학기;조진수;한철희
    • 한국항공우주학회지
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    • v.34 no.7
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    • pp.12-17
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    • 2006
  • 채널 및 레일과 같은 비평면 지면 위를 비행하는 날개들의 정상상태 공력특성 및 종방향 정안정성을 경계요소법을 사용하여 연구하였다. 펜스의 높이가 날개의 위치보다 높을 경우, 펜스와 날개와의 거리가 작아질수록 양력이 증가하고 피칭다운 모멘트가 커졌다. 레일의 폭이 날개 스팬보다 넓을 때, 레일의 높이가 낮을수록 양력이 증가하고 유도항력이 감소하였다. 종방향 정안정성 측면에서 단일 날개의 경우 비평면 지면보다 평지에서 안정한 결과를 나타내었다. 종렬배치형 날개의 경우 채널내를 비행하는 날개가 평지보다 비평면 지면에서 안정적이었다. 본 연구결과는 초고속운송체의 설계에 적용될 수 있을 것으로 기대한다.

자기부상시스템에서 레일 이음매 통과시 공극 처리방법 (Air-gap Signal Treatment at rail-joint in Maglev System)

  • 성호경;조정민;이종무;배덕권;김봉섭;김동성;신병천
    • 대한전기학회:학술대회논문집
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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.

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틸팅차량 하중에 의한 레일 이음매 하부 노반침하에 대한 수치 해석적 분석 (Numerical Analysis of the Roadbed Settlement beneath Rail Joint Induced by Tilting-Train Loading)

  • 전상수;엄기영;김재민;정두회;한성대
    • 한국방재학회 논문집
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    • v.6 no.4
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    • pp.7-14
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    • 2006
  • 기존선에 투입되는 틸팅차량은 기존 차량과는 다른 운행 메커니즘을 가지고 있으므로 안정성을 확보하기 위해서는 궤도부담력 및 주행안정성 검토와 노반의 안정성 검토가 필요하다. 본 연구에서는 레일 이음매 궤도에 대하여 틸팅차량이 궤도부담력과 주행안정성 검토에서 산정된 허용속도로 운행될 경우 발생하는 노반의 침하량을 수치해석을 통해 검토하였다. 틸팅차량 하중에 의해 발생되는 노반의 침하량과 허용침하량을 비교하여 노반의 안정성을 검토하였으며, 허용침하량과 틸팅차량 하중에 의해 발생하는 침하량의 비를 안전율이라 정의하여 안전율을 검토하였다.