• Title, Summary, Keyword: Vehicle-track interaction

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Determination of Upper Limit of Rail Pad Stiffness for Ballasted and Concrete Track of High-Speed Railway Considering Running Safety (주행 안전을 고려한 고속철도 자갈궤도 및 콘크리트궤도 레일패드의 강성 상한 결정)

  • Yang, Sin-Chu;Jang, Seung-Yup;Kim, Eun
    • Journal of the Korean Society for Railway
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    • v.14 no.6
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    • pp.526-534
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    • 2011
  • In this study, proposed is the methodology to determine the upper limit for stiffness of rail pad for the ballasted and concrete track in high-speed railway in the viewpoint of running safety, considering the dynamic characteristics of train and track and the operation environment. For the track irregularity, one of the most important input parameters for traintrack interaction analysis, the reference vertical track irregularity PSDs(power spectral densities) for the ballasted and concrete track in a wide range of frequencies were proposed based on those presented in France and Germany and that obtained from the measured data at Kyeong-Bu 1st phase high-speed railway line. Using these reference PSD models, the input data for the vertical track irregularity data were regenerated by random generation process, and then, the wheel load reduction rates according to the stiffness of the rail pads have been calculated by the train-track interaction analysis technique. Finally, by comparing the wheel load reduction rates calculated with the derailment criteria prescribed in the Korean standards for railway vehicle safety criteria, the upper limits for the stiffness of rail pad have been proposed.

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.

Vibrational Analysis of Slab Tracks Considering Wheel-Rail Interaction (차륜-레인 상호작용을 고려한 슬래브 궤도의 진동해석)

  • 이희현
    • Computational Structural Engineering
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    • v.7 no.2
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    • pp.77-87
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    • 1994
  • Vibrational analysis of slab tracks for HSR(High Speed Rail) is performed in order to find dynamic characteristics and to control noise and vibration for the tracks. Wheel-rail interactive force is included in the analysis by modelling the vehicle and track as an unsprung mass and elastically-supported-double-beam respectively, and both are assumed to be connected by the Hertzian spring. From this study, it has been found that vibration in the track and the force transmitted to the infrastructure could be reduced by controlling elasticity, mass and stiffness of the track supporting system appropriately.

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Dynamic Interaction Evaluation of Maglev Vehicle and the Segmented Switching System (자기부상열차 차량과 분기기 동적상호작용 시험 평가)

  • Lee, Jong-Min;Han, Jong-Boo;Kim, Sung-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.2
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    • pp.576-582
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    • 2017
  • The switching system in a maglev train is an indispensable element for distributing train routes, and it should be designed to ensure safe operation. Unlike conventional wheels on rails, the switching track in EMS-type maglev is supported by a group of 3 to 4 steel girders. When the vehicle changes its route, the segmented track allows the girders to change from a straight position to a curved one with a small radius of curvature. Hence, the structural characteristics of the segmented switching system may affect the levitation stability of the maglev vehicle. This study experimentally evaluates the dynamic interaction between maglev vehicles and a segmented switching system. The results may be helpful for improving the switching system. The measured levitation and lateral air gaps were evaluated at a vehicle speed of 25 km/h, and the ride quality of the Maglev vehicle was determined to be "comfortable" according to the UIC 513 standard.

Optimal Vertical Stiffness of Fastener of Concrete Track in High-Speed Railway (고속철도 콘크리트궤도 체결구 최적 수직강성)

  • Yang, Sin-Chu
    • Journal of the Korean Society for Railway
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    • v.18 no.1
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    • pp.43-52
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    • 2015
  • In this study, to minimize both the costs associated with track maintenance and the energy consumption for train operation, a numerical method that evaluates the optimal vertical stiffness of a fastener for concrete track is presented. A progress model of the track damage is established in order to calculate the concrete track maintenance cost according to the fastener stiffness. Also, the quantitative relationship between the progress of the track damage and the maintenance of the concrete track is derived. The wheel load is more exactly evaluated by using the advanced vehicle-track interaction model, which can precisely consider the behaviors of the track components. An optimal range for the stiffness of the fastener, a range that is applicable to the design of concrete track for domestic high speed lines, is proposed.

A Study on Derailment Possibility that can Analogize from Vibration and Displacement of Rolling Stocks (철도차량의 진동과 변위로부터 유추할 수 있는 탈선가능성에 관한 연구)

  • Hong, Yong-Ki;Ham, Young-Sam
    • Proceedings of the KSR Conference
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    • pp.743-748
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    • 2007
  • The important factor to evaluate the running safety of a railway vehicle would be the interaction force between wheel and rail(derailment coefficient), for which is one of important factors to check the running safety of a railway vehicle that may cause a tragic accident. Especially, a newly developed vehicle that first runs commercially requires necessarily the measurement and evaluation of derailment coefficient for securing the safety of a vehicle while measuring the derailment coefficient in view of securing running safety could be the more important factor than any other factors. In this paper, examined possibility that can forecast derailment possibility to behavior of only vibration and displacement by measuring vibration acceleration and displacement in vehicles that travel actuality rail track, and compares with data of wheel load/lateral force result.

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A study on the Development of a Driving Simulator for Reappearance of Vehicle Motion (I) (차량 주행 감각 재현을 위한 운전 시뮬레이터 개발에 관한 연구 (I))

  • Park, Min-Kyu;Lee, Min-Cheol;Son, Kwon;Yoo, Wan-Suk;Han, Myung-Chul;Lee, Jang-Myung
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.6
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    • pp.90-99
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    • 1999
  • A vehicle driving simulator is a virtual reality device which a human being feels as if the one drives a vehicle actually. The driving simulator is used effectively for studying interaction of a driver-vehicle and developing vehicle system of a new concept. The driving simulator consists of a vehicle motion bed system, motion controller, visual and audio system, vehicle dynamic analysis system, cockpit system, and etc. In it is paper, the main procedures to develop the driving simulator are classified by five parts. First, a motion bed system and a motion controller, which can track a reference trajectory, are developed. Secondly, a performance evaluation of the motion bed system for the driving simulator is carried out using LVDTs and accelerometers. Thirdly, a washout algorithm to realize a motion of an actual vehicle in the driving simulator is developed. The algorithm changes the motion space of a vehicle into the workspace of the driving simulator. Fourthly, a visual and audio system for feeling higher realization is developed. Finally, an integration system to communicate and monitor between sub systems is developed.

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Study on the Behavior of Curved Track in Honam High-Speed Line considering the Running Performanace for HEMU 430-X (HEMU 430-X 주행특성을 고려한 호남고속철도 곡선궤도구조의 거동연구)

  • Kang, Yun-Suk;Um, Ki-Young;Kim, Seog-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.8
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    • pp.4068-4076
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    • 2013
  • The wheel-rail interaction forces are influenced by the velocity of vehicle, wheel load, alignment (curve radius, cant etc). For the safety of track structure, it is required to evaluate the influences for track and influential factors. Recently, the HEMU 430-X, which was developed by Next Generation High-Speed Rail Development R&D Project, achieved 421.4km/h in a test run of Daegu.Busan section of the Gyeongbu high speed rail on March in 2013. In the case of additional speed-up test on Test-Bed Section(Gongju.Jeongeup: KP 100~128km Osong starting point), the analysis of track forces is required for outer rail by the increase of dynamic force and centrifugal force of vehicle. In this paper, the vehicle speed variation on HSL line is evaluated by TPS analysis considering the tractive effort of HEMU 430-X, tested running resistance and alignment of Honam HSR. And the track forces are evaluated by centrifugal force and impact factor on curved track.

Stochastic space vibration analysis of a train-bridge coupling system

  • Li, Xiaozhen;Zhu, Yan
    • Interaction and multiscale mechanics
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    • v.3 no.4
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    • pp.333-342
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    • 2010
  • The Pseudo-Excitation Method (PEM) is applied to study the stochastic space vibration responses of train-bridge coupling system. Each vehicle is modeled as a four-wheel mass-spring-damper system with two layers of suspension system possessing 15 degrees-of- freedom. The bridge is modeled as a spatial beam element, and the track irregularity is assumed to be a uniform random process. The motion equations of the vehicle system are established based on the d'Alembertian principle, and the motion equations of the bridge system are established based on the Hamilton variational principle. Separate iteration is applied in the solution of equations. Comparisons with the Monte Carlo simulations show the effectiveness and satisfactory accuracy of the proposed method. The PSD of the 3-span simply-supported girder bridge responses, vehicle responses and wheel/rail forces are obtained. Based on the $3{\sigma}$ rule for Gaussian stochastic processes, the maximum responses of the coupling system are suggested.

The Improvement of Incompatible Sliding Contact Problem Using Mesh Refinement And Its Application to Railway Skewed Culvert Problem (요소 세분화를 이용한 비적합 미끄러지는 접촉문제의 개선과 철도 사각암거 문제에의 적용)

  • Choi, Chan-Yong;Yeo, In-Ho;Chung, Keun-Young;Lee, Gye-Hee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.5
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    • pp.435-444
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    • 2017
  • The vehicle-track structure dynamic interaction analysis problem can be treated as sliding contact problem, and it is assumed that vehicle run at a constant speed over a rail modeled as beam elements. Unfortunately, Salome-Meca can not satisfy the compatibility condition for the beam master elements, which are consist of the elements with higher order polynomial shape function, in sliding contact problem. In this study, it is suggested to use more finer beam master element mesh as the remedy for incompatibility in sliding contact problem, and the accuracy of the solution is secured. For this, the effect of beam element mesh refinement consisting runway is analysed through simple examples, and the applicability to the dynamic interaction analysis is evaluated. Finally, the dynamic interaction analysis of railway skewed culvert transition problem is carried out to evaluate the effect of supporting stiffness due to backfill pattern changes and track irregularity due to uneven subgrade settlement.