• Title, Summary, Keyword: 차량-궤도 상호작용해석

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Determination of the Upper Limit of Railpad Stiffness in Concrete Track of High-Speed Railways Considering the Running Stability of Train (주행안정성을 고려한 고속철도 콘크리트궤도 레일패드강성 상한값 결정)

  • Yang, Sin-Chu;Jang, Seung-Yup;Kim, Eun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.485-488
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    • 2011
  • 본 연구에서는 경부고속철도의 콘크리트궤도에서 열차주행안전측면에서 관리해야할 레일패드강성의 상한값을 차량 및 궤도의 동특성과 운영환경을 고려하여 결정하는 방법을 제시하였다. 차량과궤도의 상호작용의 해석의 중요 입력파라메타인 궤도틀림과 관련하여 프랑스 및 독일에서 제시한 궤도틀림 PSD(Power Spectral Density)와 경부 1단계구간 콘크리트궤도에서 계측한 궤도틀림 자료를 통하여 얻은 PSD를 기초로 하여 넓은 범위의 주파수영역에서 적용할 수 있는 콘크리트궤도의 궤도틀림 PSD를 제시하였다. 제시된 PSD 기준모델을 사용하여 시간영역에서의 궤도틀림 입력을 Random Generation을 통하여 구한 후 개발된 차량-궤도 상호작용해석 기법을 사용하여 레일패드에 따른 윤중감소율을 산정하였다. 산정된 윤중감소율에 대하여 국내 철도차량 안전기준에 관한 규칙의 탈선계수 규정을 적용하여 주행안전측면에서 허용할 수 있는 레일패드강성의 상한값을 제시하였다.

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Dynamic Interaction of Track and Train System on Open Gap by Rail Breaks (레일 파단시 장대레일 개구부에서의 궤도-차량 동적상호작용)

  • Kang, Yun Suk;Kang, Young Jong;Yang, Shin Chu
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.6D
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    • pp.895-904
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    • 2008
  • CWR (Continuous Welded Rail) may be broken when a temperature drop below the neutral temperature changes in axial force, causing tensile fracture and rail gap, in winter. Rail-breaks may lead to the damage of the rail and wheel by dynamic load, and the reduction of running safety if not detected before the passage of a train. In this study, the track and train coupled model with open gap for dynamic interaction analysis, is proposed. Linear track and train systems is coupled by the nonlinear Herzian contact spring and the complete system matrices of total track-train system is constructed. And the interaction phenomenon considering open gap, was defined by assigning the irregularity functions between the two sides of a gap. Time history analysis, which have an iteration scheme such as $Newmark-{\beta}$ method based on Modified Newton-Raphson methods, was performed to solve the nonlinear equation. Finally, numerical studies are performed to assess the effect of various parameters of system, apply to various speeds, open gap size and the support stiffness of rail.

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Development of a Numerical Method of Vertical Train/Track Interaction in the Track Section with Hanging Sleepers (뜬침목구간에서 차량/궤도 상호작용 수치해석기법 개발)

  • Yang, Sin-Chu;Lee, Jee-Ha
    • Journal of the Korean Society for Railway
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    • v.15 no.3
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    • pp.251-256
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    • 2012
  • Hanging sleepers are frequently observed in the ballasted track with the rail of high rigidity. These hanging sleepers at the high speed line could cause such large dynamic force compared to those at the conventional line. This dynamic force would, in turn, deteriorate train running stability as well as riding comfort, and accelerate irregularity of track and failure of track materials, leading to a sharp increase in track maintenance cost. When the wheel-rail contact spring exhibits nonlinear behavior and some components of the system like hanging sleeper exhibit bi-linear behaviors, an effective analytical method is proposed for train-track interactions. The verification of the present method is carried out comparing numerical results by the present method and those by Ono's method of RTRI.

A Study of Dynamic Behavior of Track and Train Interaction on Rail Open Gap (레일 개구부에서의 궤도-차량 상호작용에 대한 연구)

  • Kang, Yun Suk;Kang, Young Jong;Yang, Shin Chu;Cho, Sun Kyu;Han, Sang Yun
    • Journal of Korean Society of Steel Construction
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    • v.19 no.4
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    • pp.345-355
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    • 2007
  • During winter, the CWR (continuous welded rail) may be broken when a temperature drop below the neutral level changes the axial force, causing tensile fracture and creating a rail gap. The passage of a train on a rail with an open gap may lead to very costly derailments. In this paper, the use of a track-and-train-coupled model whose rail has an open gap is proposed for dynamic interaction analysis. Linear track and train systems were coupled in this study by a nonlinear Herzian contact spring, and the complete system matrices of the total track-train system were constructed. Moreover, the interaction phenomenon considering the presence of an open gap in the rail was toughly defined by assigning the irregularity functions between the two sides of the gap. Time history analysis, which has an iteration scheme such as the Newmark-$\beta$ method (based on the Modified Newton-Raphson methods), was conducted to solve the nonlinear equation. .Finally, numerical studies were conducted to assess the effect of the various parameters of the system when applied to various speeds, open-gap sizes, and support stiffnesses of the rail.

Development of a Quasi-Three Dimensional Train/Track/Bridge Interaction Analysis Program for Evaluating Dynamic Characteristics of High Speed Railway Bridges (고속철도 교량의 동특성 해석을 위한 준3차원 차량/궤도/교량 상호작용 해석기법의 개발)

  • 김만철
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.2
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    • pp.141-151
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    • 2003
  • Railway bridges are subject to dynamic loads generated by the interaction between moving vehicles and the bridge structures. These dynamic loads result in response fluctuations in bridge members. To investigate the real dynamic behavior of the bridge, therefore, a number of analytical and experimental Investigations should be carried out. In this paper, a train/track/bridge interaction analysis program for evaluating the dynamic characteristics of bridges due to KTX operation in terms of structural safety, operational safety and passenger comfort is developed. To build a practical model of train/track/bridge, Hertzian spring for wheel/rail contact modeling and Winkler element for ballast are applied. This program also used torsional degree of freedom and constraint equation based on geometrical relationship in order to take into consideration three-dimensional eccentricity effect due to the operation on double track through quasi-three dimensional analysis. To verify the developed Program, comparison has been made between the measured results and those of simulation of the typical PSC box bridge(2@40m=80m) of the KHSR bridges.

The Fatigue Life Evaluation of Rail on the Concrete Track of High Speed Railway by Analysis of the Vehicle/Track Interaction (차량/궤도 상호작용해석을 통한 고속철도 콘크리트궤도 레일의 피로수명 예측)

  • Lim, Hyoung-Jun;Sung, Deok-Yong;Park, Yong-Gul
    • Journal of The Korean Society of Civil Engineers
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    • v.32 no.6D
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    • pp.663-671
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    • 2012
  • The demand of CWR is rapidly increasing because of the adaptation of concrete track, the need for rapid and comfortable ride, and the reduction of maintenance cost. Because of short applying period of the concrete track, there is not a case of CWR fracture in Korea caused by repeated load of the train, which makes it difficult to calculate replacement period of rail based on rail fatigue life using an actual field data. This study thus inspected the bending stress at rail bottom through analyzing the vehicle/track interaction, performed multiple regression analysis on the data, deducted the bending stress prediction equations by the speed and the surface irregularity. Finally, the fatigue life of CWR on the concrete track was predicted based on the prediction equations for bending stress at rail bottom.

Additional Axial Stress of CWR Track on the Bridge according to the Variation of Design Vehicle Load (설계차량하중 변화에 따른 교량상 장대레일 궤도의 부가축응력)

  • Yun, Kyung-Min;Jeon, Byeong-Heun;Choi, Shin-Hyung;Lim, Nam-Hyou
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.807-813
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    • 2015
  • The CWR(Continuous Welded Rail) on a bridge shows complex structural behavior compared to those on the roadbed. The influence factors on the track-bridge interaction are the variation of temperature and vehicle load. The analysis methods for track-bridge interaction, material property, modeling method, loads and combination method are indicated in the domestic railway design principle, KR C-08080. The vehicle load in KR C-08080 was changed in 2014. In this study, to evaluate the effect of the changed vehicle load on the track-bridge interaction, the track-bridge interaction analyses were performed for 22 bridges by using finite element method.

Development of Reliability-Based Optimum Design of High-Speed Railway Bridges Considering Structure-Rail Longitudinal Interaction and Structure-Vehicle Interaction Using Heuristic Decision Method (Heuristic Decision Method를 이용하여 구조물-궤도 종방향 상호작용 및 구조물-차량 상호작용을 고려한 고속철도 교량의 신뢰성 최적설계 기법 개발)

  • Ihm, Yeong-Rok
    • Journal of Korean Society of Hazard Mitigation
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    • v.10 no.3
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    • pp.31-38
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    • 2010
  • In this study, it is suggested that it has to reliability-based design methodology with respect to bridge structure-rail longitudinal interaction and bridge structure-vehicle interaction. For the structural analysis, commercial package, ABAQUS, are used for a three-dimensional finite element analysis. The optimization process utilizes a well-known optimizer, ADS(Automated Design Synthesis). Optimization technique is utilized the ALM-BFGS method for global area search and Golden Section Method for 1-D search. In general, ALM-BFGS method don't need the 1-D search, and that algorithm converge a 0.1~0.2 of Push-Off factor. But in this study, value of Push-Off factor is used 90, therefore 1-D search should be needed for effective convergency. That algorithm contains the "heuristic decision method". As a result of optimum design of 2-main steel girder birdge with 5${\times}$(1@50m), design methodology suggested in this study was demonstrated more economic and efficient than existing design and LCC optimization not considering bridge-rail longitudinal interaction and bridge-vehicle interaction.

Optimum Design of High-Speed Railway Bridges Considering Bridge-Rail Longitudinal Interaction and Moving Load Effect (교량-궤도 종방향 상호작용 및 동적영향을 고려한 고속철도 교량의 최적설계)

  • Ihm, Yeong-Rok;Im, Seok-Been;Park, Kwang-Young
    • Journal of Korean Society of Hazard Mitigation
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    • v.10 no.6
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    • pp.27-34
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    • 2010
  • Recently, high-speed railway systems have gained increased interest as a means of environmental friendly transportation, and numerous bridges for high-speed railways have been constructed accordingly. However, bridge design for high-speed railways requires more consideration than conventional railway design because fast-moving trains will lead to significant impact on bridge structures. Thus, this research proposes a revised design considering both bridge-rail longitudinal interaction and dynamic effect of trains to ensure stability of fast travelling trains. To validate the proposed design algorithm, numerical analyses are performed and compared using a constructed 250 m long bridge with 5 spans for a high-speed railway. From the numerical results, the proposed optimum design of high-speed railway bridges exhibits the most economic life-cycle-cost (LCC) when compared with several existing design approaches.