• Title, Summary, Keyword: 궤도틀림

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Characteristics of Track Irregularities on Kyoungbu High-speed Line (경부고속선 궤도틀림 분포특성)

  • Choi, Il-Yoon;Lee, Jun S.;Um, Ju-Hwan;Kang, Tae-Ku;Choi, Min-Ji
    • Journal of the Korean Society for Railway
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    • v.18 no.1
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    • pp.63-70
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    • 2015
  • Track irregularities have a strong influence on the safety and the ride comfort of trains as well as track maintenance work. A statistical analysis was conducted for track irregularities data measured in Kyoungbu high speed line using a track recording car(EM120). First, the characteristics of EM120, which adopted versine measurement system, were investigated and the transfer function of EM120 was examined. The distributions of the surface and the alignment which have short wavelength were considerably high and the distribution decreased as wavelength increases. A distribution analysis of the wavelength was carried out according to EN standards and most of the track irregularities were in a D1 wavelength range. The distributions of the amplitude of track irregularities were also investigated and the results show that the distributions of track irregularities decrease rapidly as amplitude increases. These results may be helpful in making track maintenance plans and revising track irregularities criteria.

Analysis on Safety and Ride Comfort of KTX According to Track Surface (고저틀림에 따른 KTX 주행거동 특성 분석)

  • Choi, Il-Yoon;Koo, Dong-Hoe;Hwang, Seok-Yeol;Lim, Yun-Sik
    • Journal of the Korean Society for Railway
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    • v.13 no.6
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    • pp.583-588
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    • 2010
  • Track irregularities is one of key factors influencing running behavior of train. In order to ensure safety and ride comfort, it is highly important that relationship between track irregularity and running behavior of vehicle is identified and the criteria for track irregularities is adequately established. Numerical analysis was conducted to investigate influence of surface on running behavior of KTX and various wavelength and amplitude of surface were considered in numerical analysis. Derailment, lateral load, bogie acc., body acc. of numerical analysis results were investigated to evaluate the effect on track profile on safety and ride comfort of KTX.

Identification of Track Irregularity using Wavelet Transfer Function (웨이브렛 전달함수를 이용한 궤도틀림 식별)

  • Shin, Soo-Bong;Lee, Hyeung-Jin;Kim, Man-Cheol;Yoon, Seok-Jun
    • Journal of the Korean Society for Railway
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    • v.13 no.3
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    • pp.304-308
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    • 2010
  • This paper presents a methodology for identifying track irregularity using a wavelet transfer function. An equivalent wavelet SISO (single-input single-output) transfer function is defined by the measured track geometry and the acceleration data measured at a bogie of a train. All the measured data with various sampling frequencies were rearranged according to the constant 25cm reference recording distance of the track recording vehicle used in the field. Before applying the wavelet transform, measured data were regressed by eliminating those out of the range. The inverse wavelet transfer function is also formulated to estimate track geometry. The closeness of the estimated track geometry to the actual one is evaluated by the coherence function and also by FRF (frequency response function). A track irregularity index is defined by comparing the variance of the estimation error from the intact condition and that from the current condition. A simulation study has been carried out to examine the proposed algorithm.

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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Analysis of the Influence of Track Alignment on Ride Comfort and Safety of KTX (방향틀림이 KTX 주행거동에 미치는 영향 분석)

  • Choi, Il-Yoon;Um, Ju-Hwan;Kim, Man-Cheol
    • Journal of the Korean Society for Railway
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    • v.16 no.2
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    • pp.110-116
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    • 2013
  • Track irregularities is one of the key factors influencing the running behavior of trains. In order to ensure safety and ride comfort of train, the criteria for track irregularities should be adequately established regarding vehicle velocity, vehicle characteristics, characteristics of the track recording car, and measurement interval. Also, track maintenance should be carried out thoroughly according to the criteria for managing track irregularities. Numerical analysis was conducted to investigate the influence of track alignment on the running behavior of Korean high speed train(KTX). Various wavelengths and amplitudes of lateral alignment were considered as parameters for this study using the Vampire program, a vehicle dynamics modeling package in railway environment. Derailment, lateral load, bogie acceleration and body acceleration of numerical analysis results due to alignment were investigated. Finally, the influence of the alignment on safety and ride comfort for the KTX was evaluated. This study indicates that alignment irregularities have significant impacts on running safety, and that the criteria used to manage alignment irregularities should be restrictive to ensure the running safety of the KTX.

Identification of Track Irregularity by Frequency-Domain Transfer Function (주파수영역 전달함수를 이용한 궤도틀림 식별)

  • Kim, Jae-Cheon;Kwon, Soon-Jung;Yin, Jing-Lin;Lee, Hyeung-Jin;Kim, Man-Cheol;Shin, Soo-Bong
    • Journal of the Korean Society for Railway
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    • v.12 no.4
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    • pp.506-511
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    • 2009
  • An algorithm for identifying track irregularities along the railway is presented. A baseline frequency-domain transfer function based on the equivalent SlSO(Single Input Single Output) model is defined at the intact condition between the measured track geometry of the ground displacement and the acceleration measured at a location in a train. The pre-defined transfer function at the intact condition is used inversely to predict track geometry in time with the currently measured acceleration at the same location in a train. The predicted track geometry is compared in time with that of the baseline values at the intact condition. The difference between them is calculated as an error in time and used to identify the track irregularities. An irregularity index is proposed as the ratio between the moving variance of the error at the current inspection and that at the intact condition. A 3D numerical simulation study has been carried out with a train model to verify the validity of the presented algorithm. In the analysis for the simulation, the track geometry has been considered as the displacement boundary condition varying in time.

스펙트럼 해석의 역사와 배경

  • 서사범
    • Journal of the Korean Society for Railway
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    • v.6 no.4
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    • pp.30-36
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    • 2003
  • 궤도(track)는 열차가 안전하고 승차감(乘車感)이 좋게 운행되도록 충분한 강도를 가지고 더욱이 양호한 상태로 정비되어 있어야 한다. 일반적으로, 토목구조물(structure)은 하중을 받으면 변위(變位)ㆍ변형하고, 하중이 없게 되면 원래대로 되돌아간다. 즉, 각 부재는 탄성 한계 내로 응력(應力)이 들어가도록 설계된다. 그러나, 궤도는 열차의 하중과 진동을 궤도 자신의 변위 축적으로 흡수하고 있다. 결국, 처음부터 틀림이 진행되어 가는 것을 전제로 한 유일한 구조물이다. 일반적으로는 스프링 하 중량과 축중(軸重)이 큰 차량이 빠르고 대량으로 주행하게 되면 궤도 틀림이 발생하여 진행한다. 궤도 틀림 파형의 성장은 궤도 틀림이라고 하는 공간적인 파형의 시간적인 추이라고 하는 2차원적인 취급이 필요하다. (중략)

Study on the Appropriateness of Track Maintenance Works through the Evaluation of Trackbed Conditions (도상 및 노반상태 평가를 통한 궤도유지보수작업의 적정성 연구)

  • Kim, Dae-Sang;Kwon, Soon-Sup;Lee, Su-Hyung;Hwang, Seon-Keun;Park, Tae-Soon
    • Journal of the Korean Society for Railway
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    • v.11 no.3
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    • pp.334-341
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    • 2008
  • Ballast track needs maintenance works because it is supported by the compressible trackbed and subgrade layers. Maintenance works are essential to secure riding comfort and extend the life cycle of it. The necessities of maintenance works are determined from track irregularities measured by EM120. Track irregularities is the results of the track deformation. Therefore, it is natural to evaluate the cause of it. This paper focuses on the points the track irregularities come from the trackbed and the subgrade. Nondestructive techniques, such as Ground Penetrating Radar (GPR) and Portable Falling Weight Deflectometer (PFWD) are applied to evaluate the trackbed conditions, ballast layer thickness and vertical track stiffness, in the test section 500m long of Gyungbu line. The trackbed investigation results are compared with the track irregularities measured by EM120 and maintenance works. Conclusively, it was found that some maintenance works were unnecessary on the test section.

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.

Study for Progress Rate of Standard Deviation of Irregularity Based on Track Properties for the Railway Track Maintenance Cycle Analysis (궤도 유지보수 주기 예측을 위한 구간 특성에 따른 궤도틀림 표준편차 진전정도 분석)

  • Jeong, Min Chul;Kim, Jung Hoon;Lee, Jee Ha;Kang, Yun Suk;Kong, Jung Sik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.3
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    • pp.31-40
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    • 2012
  • The irregularity of railway track affects not only the comfort of ride such as noise or vibration but also the safety of train operation. For this reason, it is an interesting research area to design a reliable and sustainable railway track system and to analyze the train movement mechanism based on systematic approaches considering reasons of track irregularity possible in a specific local environment. Irregularity data inspected by EM-120, an railway inspection system in Korea includes unavoidable incomplete and erratic information, so it is encountered lots of problem to analyse those data without appropriate pre-data-refining processes. In this research, for the efficient management and maintenance of railway system, progress rate of standard deviation of irregularity is quantified. During the computation, some important components of railways such as rail joint, ballast, roadbed, and fastener have been considered. Probabilistic distributions of irregularity growth with respect to time are computed to predict the remaining service life of railway track and to be adapted for the safety assessment.