• Title, Summary, Keyword: Train and track interaction

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Dynamics of high-speed train in crosswinds based on an air-train-track interaction model

  • Zhai, Wanming;Yang, Jizhong;Li, Zhen;Han, Haiyan
    • Wind and Structures
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    • v.20 no.2
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    • pp.143-168
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    • 2015
  • A numerical model for analyzing air-train-track interaction is proposed to investigate the dynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of a train-track interaction model and a train-air interaction model. The train-track interaction model is built on the basis of the vehicle-track coupled dynamics theory. The train-air interaction model is developed based on the train aerodynamics, in which the Arbitrary Lagrangian-Eulerian (ALE) method is employed to deal with the dynamic boundary between the train and the air. Based on the air-train-track model, characteristics of flow structure around a high-speed train are described and the dynamic behavior of the high-speed train running on track in crosswinds is investigated. Results show that the dynamic indices of the head car are larger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the running safety of the train in crosswinds is basically controlled by the head car. Compared with the generally used assessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio, the overturning coefficient will overestimate the running safety of a train on a track under crosswind condition. It is suggested to use the wheel-load reduction ratio and the lateral wheel-rail force as the dominant safety assessment indices when high-speed trains run in crosswinds.

Study on Effects of Rail Pad Vertical Stiffness by Train/Track Interaction Analysis (차량/궤도 상호작용해석을 통한 레일패드강성 영향 분석)

  • Yang Sin-Chu
    • Proceedings of the KSR Conference
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    • pp.800-805
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    • 2004
  • In this paper, a numerical method for train/track/structure interaction analysis in frequency domain is developed. Track is modelled as continuous beams supported by elastomers. The motion of train is expressed by those of car body, bogies and unsprung masses supported by springs and dampers. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The Effects of rail pad stiffness on the behaviors of train and track are analyzed using the presented method.

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A Method for the Analysis of Train/Slab-Track Interaction on Settled Roadbed (슬래브궤도 노반침하구간 차량/궤도 상호작용 해석기법 개발)

  • Yang, Sin-Chu;Hong, Chul-Kee
    • Journal of the Korean Society for Railway
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    • v.10 no.3
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    • pp.296-305
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    • 2007
  • A numerical method for the analysis of train/slab-track interaction on the settled roadbed is developed based on the already developed analysis method of train/ballast-track interaction. The concrete slabs composed of the upper track concrete layer and the lower hydraulic bonded layer are modelled by a equivalent beam. The supporting stiffness of roadbed is evaluated with the modified boussinesq method suggested by Eisenmann. The track irregularity and the gap between slab and roadbed induced by settlement of roadbed are calculated by the effective method newly presented in this study. The validation of the developed method is investigated by a numerical example. The effects of train speed on train and slab track on the settled roadbed with sinusoidal shape of wave length 20m and amplitude 20mm are reviewed.

The Effect of Gaps in Concrete Bearing Surface of Direct Fixation Track on Vehicle and Track Interaction (직결궤도 체결구 하부에 발생한 단차가 차량/궤도 상호작용에 미치는 영향)

  • Yang, Sin-Chu;Kim, Eun
    • Proceedings of the KSR Conference
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    • pp.50-57
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    • 2010
  • Various installation faults may lie in fasteners in the construction of a direct-fixation track by the top-down method. At an extreme, they may cause excessive interaction between the train and track, compromise the running safety of the train, and cause damage to the track components. Therefore, the faults need to be kept within the allowable level through an investigation of their effects on the interactions between the train and track. In this study, the vertical dynamic stiffness of fasteners in installation faults was measured based on the dynamic stiffness test by means of an experimental apparatus that was devised to feasibly reproduce gap faults. This study proposes an effective analytical model for a train-track interaction system in which most elements, except the nonlinear wheel-rail contact and some components that behave bi-linearly, exhibit linear behavior. To investigate the effect of the behavior of fasteners in gap faults in a direct-fixation track on the vehicle and track, vehicle-track interaction analyses were carried out, targeting key review parameters such as the wheel load reduction factor, vertical rail displacement, rail bending stress, and mean stress of the elastomer. From the results, it was noted that the gap faults in the concrete bearing surface of a direct-fixation track need to be limited for the sake of the long-term durability of the elastomer than for the running safety of the train or the structural safety of the track.

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Train/Track/Bridge Interaction Analysis Using 2-Dimensional Articulated High-Speed Train Model (2차원 관절형 고속열차 모델을 이용한 차량/궤도/교량 상호작용해석)

  • 김만철;양신추;이종득
    • Proceedings of the KSR Conference
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    • pp.414-421
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    • 1999
  • In this paper, the simplified method for 2-dimensional train/track/bridge interaction analysis is utilized in the analysis of dynamic behavior of bridges in which the eccentricity of axle loads and the effect of the toriosnal forces acting on the bridge are included for the more accurate train/track/bridge interaction analysis. Inverstigations mainly into the influence of vehicle speed on train/track/bridge interactions are carried out for the two cases. The first case is that only train and bridge are considered in the modelling and the other case is that train, track and bridge are considered.

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A Study on the Criteria of Settlement in Concrete Slabtrack (토노반상 콘크리트궤도의 노반허용침하기준설정에 관한 연구)

  • Hong, Chul-Kee;Yang, Shin-Chu;Kim, Yun-Tae
    • Journal of the Korean Society for Railway
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    • v.10 no.3
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    • pp.355-364
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    • 2007
  • Recently a concrete slab tracks are being constructed on roadbed in the Gyoeng-bu 2nd phase high speed railways. In respdnding to this trend, new design standards and track materials maintenance systems, based on the slab track material safety and usage perspective, are needed. This research provides a roadbed design criteria and the maintenance system. The proposed roadbed design criteria and the maintenance system are based on the developed analysis meathod of train/slab-track interaction. where the roadbed settlement and train speed are utilized as mediating variables. In the analysis, the dynamic response of train/slab-track interaction apply to various speeds and settlements. the roadbed settlement is shown in a sinusoidal shape of wave, the scope of the settlement occurrence presented in its wavelengths, include 6meters, 10meters, 15merwes, 20meters, 30meters. The train speeds involved are 50, 100, 150, 200, 250, 300, 350, 400kilometers per hour.

Evaluation of Dynamic Stability of KHSR Bridges Using Train/Track/Bridge Interaction Analysis Method (차량/궤도/교량 상호작용 해석법을 이용한 한국고속철도 교량의 동적안전성 평가)

  • 김만철;나성훈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1015-1021
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    • 2001
  • This paper represents the results carried out to determine the dynamic response characteristics of Korea High Speed Rail(KHSR) bridges. The responses of the KHSR bridges subjected to the moving train loading are obtained through the simplified method for the 2-dimensional train/track/bridge interaction analysis in which the eccentricity of axle loads and the effect of the torsional forces acting on the bridge are included for the more accurate train/track/bridge interaction analysis. The results of the analyses are compared with the field test data to verify the performance of the 2-dimensional train/track/bridge interaction analysis method.

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Development of a Numerical Analysis Method of Train/Track Interaction for Evaluation of Dynamic Track Design Load (궤도 설계 동하중 산정을 위한 차량/궤도 상호작용 해석기법 개발)

  • 양신추
    • Proceedings of the KSR Conference
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    • pp.1094-1099
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    • 2002
  • In this paper, a numerical method for vehicle-track interaction analysis is developed to evaluate vertical dynamic force subjected to rail surface. A vehicle is modelled by lumped masses system and track by multi layered continuous beam system. The equation of motion of vehicle and track interaction system is derived by considering compatibility condition at the contact points between wheel and rail. The input vibration source is given by the empirical formula of power spectral density of track irregularity, which is suggested by FRA. Using this method, dynamic impact factors with the train speed are evaluated.

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Performance Evaluation of KHSR Bridges Using 2-D Train/Track/Bridge Interaction Analysis Method (2차원 상호작용 해석법을 이용한 한국고속철도 교량의 성능평가)

  • 김만철;심성택;이희연
    • Proceedings of the KSR Conference
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    • pp.366-373
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    • 2000
  • This paper represents the results carried out to determine the dynamic response characteristics of Korea High Speed Rail(KHSR) bridges. The responses of the KHSR bridges subjected to the moving train loading are obtained through the simplified method for the 2-dimensional train/track/bridge interaction analysis in which the eccentricity of axle loads and the effect of the torsional forces acting on the bridge are included for the more accurate train/track/bridge interaction analysis. The results of the analyses are compared with the field test data to verify the performance of the 2-dimensional train/track/bridge interaction analysis method.

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Effects of Expansion of Sleeper Span at the Deck End of a Long Continuous Bridge on Train Safety and Track Stability (장대교량 신축부에서 침목간격 확대가 차량의 주행안전성 및 궤도의 구조안정성에 미치는 영향)

  • Yang, Sin-Chu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.9
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    • pp.620-627
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    • 2015
  • Long continuous bridge deck can become contracted considerably as temperature drops, which can lead to a large expansion of sleeper span at the end of it. Since this huge sleeper span then can cause problems both with safety of train operation and structural stability of tracks, it is necessary to take the issue into consideration systematically in the designing process of the bridge. In this paper, an evaluation process through the analysis of train-track interaction was presented which can basically review the effects of the expansion of sleeper span at the end of long continuous bridge deck on the safety of the train and the structural stability of the track. The analyses of the interaction between the light rail train and tracks were carried out targeting the sleeper span as a main parameter. The safety of train operation and structural stability of tracks in a light rail system due to the expansion of the sleeper span were evaluated by comparing the numerical results with the related criteria.