• Title, Summary, Keyword: 차량-궤도 상호작용해석

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Dynamic Change of Stresses in Subsoil under Concrete Slab Track Subjected to Increasing Train Speeds (열차 증속에 따른 콘크리트 궤도 노반의 동적 응력 변화)

  • Lee, Tae-Hee;Choi, Chan-Yong;Nsabimana, Ernest;Jung, Young-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.29 no.10
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    • pp.57-66
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    • 2013
  • Societal interest on a faster transportation demands an increase of the train speed exceeding current operation speed of 350 km/h. To trace the pattern of variations in displacements and subsoil stresses in the concrete slab track system, finite element simulations were conducted. For a simple track-vehicle modeling, a mass-point system representing the moving train load was developed. Dynamic responses with various train speeds from 100 to 700 km/h were investigated. As train speeds increase the displacement at rail and subsoil increases nonlinearly, whereas significant dynamic amplification at the critical velocity has not been found. At low train speed, the velocity of elastic wave carrying elastic energy is faster than the train speed. At high train speed exceeding 400 km/h, however, the train speed is approximately identical to the elastic wave velocity. Nonlinearity in the stress history in subsoil is amplified with increasing train speeds, which may cause significant plastic strains in path-dependent subsoil materials.

A Study on Optimum Design for Railway Alignment in Curve (곡선부 최적 선형 설계기법에 관한 연구)

  • Um, Ju-Hwan;Yang, Sin-Chu;Kim, Eun-Kyum
    • Journal of the Korean Society for Railway
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    • v.12 no.4
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    • pp.597-603
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    • 2009
  • In this study, Based on the optimization developed in Um et al. (2009), optimum design method of the alignment when building new lines and renewing existing ones is presented. The object function used for optimization is passenger comfort ($P_{CT}$) which was proposed in BSI (2006). Other aspects of track/vehicle interaction will be treated in boundary conditions. And track/vehicle interaction analysis is peformed using KTX-II model. From the analysis results, it was found that the optimum alignments are affected by the angle (I) between adjacent straight lines and $R-L_t$ combinations. Also the dynamic analysis confirms well the results from the simplified analysis. However, In the most cases, the $P_{CT}$ values in the dynamic analysis are higher than the simplified $P_{CT}$ values. If both methods are used when optimizing the alignment, it will be possible to design the alignments more rapidly and reliably.

Simulation of Vehicle-Track-Bridge Dynamic Interaction by Nonlinear Hertzian Contact Spring and Displacement Constraint Equations (비선형 헤르쯔 접촉스프링과 변위제한조건식의 적용에 의한 차량-궤도-교량 동적상호작용 수치해석기법)

  • Chung Keun-Young;Lee Sung-Uk;Min Kyung-Ju
    • Proceedings of the KSR Conference
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    • pp.191-196
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    • 2005
  • In this study, to describe vehicle-track-bridge dynamic interaction phenomena with 1/4 vehicle model, nonlinear Hertzian contact spring and nonlinear contact damper are introduced. In this approach external loads acting on 1/4 vehicle model are self weight of vehicle and geometry information of running surface. The constraint equation on contact surface is implemented by Penalty method. Also, to improve the numerical stability and to maintain accuracy of solution, the artificial damper and the reaction from constraint violation are introduced. A nonlinear time integration method, in this study, Newmark method is adopted for both equations of vehicles and structure. And to reduce the error caused by inadequate time step size, adaptive time-stepping technique is partially introduced. As the nonlinear Hertzian contact spring has no resistance to tensile force, the bouncing phenomena of wheelset can be described. Thus, it is expected that more versatile dynamic interaction phenomena can be described by this approach and it can be applied to various railway dynamic problems.

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Simulation and Experimental Study on the Impact of Light Railway Train Bridge Due to Concrete Rail Prominence (주행면 단차에 의한 경량전철 교량의 충격 시뮬레이션 및 실험)

  • Jeon, Jun-Tai;Song, Jae-Pil
    • Journal of The Korean Society of Civil Engineers
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    • v.30 no.1A
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    • pp.45-52
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    • 2010
  • This study pointed on the dynamic impact of AGT (Automated Guide-way Transit) bridge, due to concrete rail prominence. An experiment was done with 30 m P.S.C. bridge in AGT test line in Kyungsan. An artificial prominence with 10 mm hight, was installed at the mid span of concrete rail. And computer simulation was executed for the artificial prominence. As an experiment result, in the case of with prominence, bridge acceleration responses are increased 50% at the speed range of 20 km/h-60 km/h, and bridge displacement responses increased slightly. With these results, the prominence of concrete rail can be induce excess impact and vibration. And the computer program simulated much the same as experiments. So this program can be used for AGT bridge design and formulate the standard of concrete rail management.

Nonlinear Dynamic Analysis of Vehicle-Bridge Interaction considering the Hertzian Contact Spring and Rail Irregularities (헤르쯔 접촉스프링과 레일 요철을 고려한 차량-교량 동적상호작용 비선형 해석)

  • Kang, Young-Jong;Neuyen, Van-Ban;Kim, Jung-Hun;Kang, Yoon-Suk
    • Proceedings of the KSR Conference
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    • pp.1478-1485
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    • 2010
  • In this paper, the nonlinear dynamic response of Vehicle-Bridge interaction with the coupled equations of motion including nonlinear Hertzian contact is presented. The moving train model is chosen to have 10 degrees of freedom (DOF). The bridge is modeled as 2D Euler-Bernoulli beam element with 4 DOF for each element, two for rotations and another two for translations. The nonlinear Hertzian contact is used to simulate the interaction between vehicle and bridge. Base on the relationship of wheel displacement of the vehicle and the vertical displacement of the bridge in Hertzian contact, the coupled equations of motion of the whole system is derived. The convenient formulation was encoded into a computer program. The contact forces, contact area and stress of the rail surface were also computed. The accuracy and efficiency of the proposed program are verified and compared with exact analytical solution and other previous studies. Various numerical examples and parametric studies have demonstrated the versatility and applicability of the proposed program.

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A Long-Term Friction Test of Bridge Bearings Considering Running Speed of Next Generation Train (차세대 고속철 주행속도를 대비한 교량받침의 장기마찰시험법)

  • Oh, Soon-Taek;Lee, Dong-Jun;Jun, Sung-Min;Jeong, Shin-Hyo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.2
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    • pp.34-39
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    • 2016
  • Structural behaviour of PSC box bridge, on which KTX train runs, is analysed up to 500 km/h speed considering 12 stages track irregularity and interaction between bridge and vehicle. To evaluate wheel forces and rotations of vehicle, lateral wheel forces, derail factor and offload factor calculated on the track combining the bridge and 170 m normal track are compared with existing allowed limits. Maximum longitudinal displacement and accumulated sliding distance of the brige bearings for simply supported and 2 span continuous PSC bridges are presented by each running speeds. Long-term friction tests based on EN-1337-2 are conducted between PTFE and DP-mate plates. Finally, the long-term friction tests are proposed to consider the increasing speed of next generation high-speed train.