• Title, Summary, Keyword: Rail Stability

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The Evaluation of Axial Stress in Continuous Welded Rails via Three-Dimensional Bridge-Track Interaction

  • Manovachirasan, Anaphat;Suthasupradit, Songsak;Choi, Jun-Hyeok;Kim, Bum-Joon;Kim, Ki-Du
    • International journal of steel structures
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    • v.18 no.5
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    • pp.1617-1630
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    • 2018
  • The crucial differences between conventional rail with split-type connectors and continuous welded rails are axial stress in the longitudinal direction and stability, as well as other issues generated under the influence of loading effects. Longitudinal stresses generated in continuously welded rails on railway bridges are strongly influenced by the nonlinear behavior of the supporting system comprising sleepers and ballasts. Thus, the track structure interaction cannot be neglected. The rail-support system mentioned above has properties of non-uniform material distribution and uncertainty of construction quality. The linear elastic hypothesis therefore cannot correctly evaluate the stress distribution within the rails. The aim of this study is to apply the nonlinear finite element method using the nonlinear coupling interface between the track and structural model and to illustrate the welded rail behavior under the loading effect and uncertain factors of the ballast. Numerical results of nonlinear finite analysis with a three-dimensional solid and frame element model are presented for a typical track-bridge system. A composite plate girder, modeled by solid and shell elements, is also analyzed to consider the behavior of the welded rail. The analysis result showed buckling under the independent calculations of load cases, including 'temperature change', 'bending of the supporting structure', and 'braking' of the railway vehicle. A parametric study of the load combination method and the loading sequence is also included in this analysis.

A study on stability of feeder system considering driving of railway vehicle and rail conditions (철도차량 운행 및 선로조건에 따른 교류 급전시스템의 안정성 연구)

  • Kim, Jae-Moon;Kim, Yang-Su;Lee, Jong-Sung
    • Proceedings of the KIEE Conference
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    • pp.2213-2214
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    • 2011
  • It is important to consider power stability in case of design and construction of a substation at railroad because a train is operated by electricity and tains are drived simultaneous at the same section. This paper described stability of feeder system considering driving conditions and railroad conditions of train which is drived. Simulation tool, TOM(Train Operations Model) software is used to ensure stability of feeder system. As results of simulation, feeder voltage source is in limits on driving operation dia of trains.

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Study of the Characteristic and reliability of guide rail and clamp for the Y-beam type monorail (Y Beam형 모노레일의 가이드 레일 및 클램프의 특성과 안전성에 관한 연구)

  • Ko, H.K.;Kim, Y.S.;Nam, D.H.;Jung, S.Y.;Cheon, S.W.
    • Proceedings of the KSR Conference
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    • pp.1416-1422
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    • 2010
  • Monorail has been classified as straddled type and suspended type. However, Inchon Wolmi Eunha rail, a center guide type first ever introduced in the world, uses a new concept Y-Beam as guide rail. Since Y-Beam takes horizontal loads of monorail through guide wheels, it is an essential structure for the safe operation along with concrete surface and steel beam which take vertical loads through main tires. This study presents the characteristic and reliability of Y-Beam and Y-Beam fixture, clamp, which are not only taking horizontal loads but also guarantying both guiding and stability of monorail and holding power supply line.

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A Competition-based Algorithm for Routing Discovery and Repair in Large-scale VANET

  • Wu, Cheng;Wang, Lujie;Wang, Yiming
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.12
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    • pp.5729-5744
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    • 2017
  • Vehicular Ad Hoc Networks (VANET) in the large-scale road section usually have typical characteristics of large number of vehicles and unevenly distribution over geographic spaces. These two inherent characteristics lead to the unsatisfactory performance of VANETs. This poor performance is mainly due to fragile communication link and low dissemination efficiency. We propose a novel routing mechanism to address the issue in the paper, which includes a competition-based routing discovery with priority metrics and a local routing repair strategy. In the routing discovery stage, the algorithm uses adaptive scheme to select a stable route by the priorities of routing metrics, which are the length of each hop, as well as the residual lifetime of each link. Comparisons of different ratios over link length and link stability further show outstanding improvements. In the routing repair process, upstream and downstream nodes also compete for the right to establish repair process and to remain as a member of the active route after repair. Our simulation results confirm the improved performance of the proposed algorithm.

Effects of wind barriers on running safety of trains for urban rail cable-stayed bridge

  • He, Wei;Guo, Xiang-Rong;Zhu, Zhi-hui;Deng, Pengru;He, Xu-hui
    • Wind and Structures
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    • v.31 no.1
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    • pp.43-57
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    • 2020
  • Considering the wind barriers induced aerodynamic characteristic variations of both bridge deck and trains, this paper studies the effects of wind barriers on the safety and stability of trains as they run through an urban rail transit cable-stayed bridge which tends to be more vulnerable to wind due to its relatively low stiffness and lightweight. For the bridge equipped with wind barriers of different characteristics, the aerodynamic coefficients of trains and bridge decks are obtained from wind tunnel test firstly. And then, the space vibration equations of the wind-train-bridge system are established using the experimentally obtained aerodynamic coefficients. Through solving the dynamic equations, one can calculate the dynamic responses both the trains and bridge. The results indicate that setting wind barriers can effectively reduce the dynamic responses of both the trains and bridge, even though more wind forces acting on the bridge are caused by wind barriers. In addition, for urban rail transit cable-stayed bridges located in strong wind environment, the wind barriers are recommended to be set with 20% porosity and 2.5 m height according to the calculation results of cases with wind barriers porosity and height varying in two wide ranges, i.e., 10% - 40% and 2.0 m to 4.0 m, respectively.

A Comparative Study between the Deterministic and Probabilistic Approach Analysis on Buckling Stability of CWR Tracks (CWR 궤도의 좌굴 안정성에 대한 결정론적 해석과 확률론적 해석 비교)

  • Bae, Hyun-Ung;Choi, Jin-Yu;Shin, Jeong-Sang;Kim, Jong-Jung;Lim, Nam-Hyoung
    • Proceedings of the KSR Conference
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    • pp.988-992
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    • 2011
  • The buckling characteristics of the continuous welded rail track(CWR) is uncertainly varied by many influence factors, such as rail temperature, operating conditions of a train and maintenance of the track etc. Therefore, applying the probabilistic approach method is essential to rationally consider uncertainty and randomness of the various parameters that affect the track buckling. In this study, the probabilistic approach analysis was carried out and the results were compared with the deterministic approach using the buckling probability evaluation system of CWR tracks developed by our research team. From the comparison, it was identified that a probabilistic approach can quantitatively assess the reliability of the CWR tracks based on failure probability and can be used as a tool for decision making in track design, maintenance and operating etc.

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Experimental Verification of Design Parameters of Track (실측을 통한 궤도설계 파라메타의 검증)

  • Lee Jee-Ha;Hwang Sung-Ho;Na Sung-Hoon;Kim Jung-Hwan;Suh Sa-Bum
    • Proceedings of the KSR Conference
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    • pp.1065-1070
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    • 2004
  • When the track designer analyze the track structure uses many known & unknown parameters. Unknown parameters, equivalent rail support spring factor, unit rail support spring factor, track damping coefficient, should be assumed. Known parameters are section properties (area, section factor, etc), material properties(modulus of elasticity, mass, etc) and track conditions(wheel load, loading conditions, gauge, etc.). In the assumption of track design parameters, some parameters can be overestimated or under estimated. The purpose of this study is to verify design parameters used in track design, in the way of experimental measurements. Data of displacements, banding stresses, loads, accelerations are measurable at track site. From these data, unknown parameters are derived. Compare these assumed and derived parameters, estimate the entire track stability.

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Quayside Container Cranes in Year 2013

  • Lee, Suk-Jae;Hong, Keum-Shik
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.437-442
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    • 2004
  • In this paper, design specifications for a new generation container crane in year 2013 is investigated. After analyzing the trend of the development of container cranes from the 1950s to date, a prospective size for targeting year 2013 is proposed. Introductory specifications of the frame, trolley, hoist and spreader for the proposed new crane are discussed. Considering that the mega-ships will load and unload more than 15000 boxes at one stop, rough dimensions of the crane including outreach, rail gage, lift, backreach, etc. are also suggested. Although the sheer size of the cranes already present some challenges, the biggest challenge is to improve productivity by maximizing the moves per hour. For this, the speeds of trolleys and hoists, rail loads, stability, etc. are discussed.

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Analysis of CWR track on the High-Speed Railway Bridges considering the Expansion Length of Bridge Deck (고속철도교량의 온도신축길이 변화를 고려한 교량상 장대레일의 거동 해석)

  • Kang Jae-Yoon;Kim Byung-Suk;Kwark Jong-Won;Choi Eun-Suk;Chin Won-Jong
    • Proceedings of the KSR Conference
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    • pp.806-811
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    • 2004
  • Currently, in the design criteria for the high speed railway bridges, the maximum distance between bridge expansion joint is limited to 80m using a continuous welded mil, in order to limit the additional stress in the rail due to the rail-bridge interaction. In the past study on the resonance effect of HSR train, it is known that the reduction of resonance and dynamic responses of bridge deck occurs at the specific expansion length of 28.05m and 46.75m. In this study, the stability of track structure on the HSR bridges with expansion length of 90m has checked by finite element method. And the track behavior including mil stresses and relative displacements are compared to the current state of track structures on the bridge system with 80m long expansion length.

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Running Stability Test of Developed Bogie for High Speed Train on the Roller Rig (주행 시험대에서의 고속전철 개발대차의 주행안정성 평가)

  • Kim, Jin-Tae;Oh, Hyeong-Sik;Jung, Hoon
    • Proceedings of the KSR Conference
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    • pp.839-844
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    • 2002
  • This research aims to test the running stability of the developed bogie with maximum operating speed of 350km/h, which of Korea TGV was 300km/h. The running stability test has been executed in status of a dummy car with one developed bogie and one dummy bogie on the roller rig to embody similar operation condition. The test has been done in the two rail conditions, i.e. excitation and non-excitation, respectively. Running speed has been increased by the roller step by step. In consequence, the developed bogie was proven to be able to run upto 400 Km/h without any unstable point in the non-excitation. Vibration characteristics of carbody also was within the value specified on the UIC 515.

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