• 제목, 요약, 키워드: Rail stress

검색결과 251건 처리시간 0.031초

Interaction analysis of Continuous Slab Track (CST) on long-span continuous high-speed rail bridges

  • Dai, Gonglian;Ge, Hao;Liu, Wenshuo;Chen, Y. Frank
    • Structural Engineering and Mechanics
    • /
    • v.63 no.6
    • /
    • pp.713-723
    • /
    • 2017
  • As a new type of ballastless track, longitudinal continuous slab track (CST) has been widely used in China. It can partly isolate the interaction between the ballastless track and the bridge and thus the rail expansion device would be unnecessary. Compared with the traditional track, CST is composed of multi layers of continuous structures and various connecting components. In order to investigate the performance of CST on a long-span bridge, the spatial finite element model considering each layer of the CST structure, connecting components, bridge, and subgrade is established and verified according to the theory of beam-rail interaction. The nonlinear resistance of materials between multilayer track structures is measured by experiments, while the temperature gradients of the bridge and CST are based on the long-term measured data. This study compares the force distribution rules of ballasted track and CST as respectively applied to a long span bridge. The effects of different damage conditions on CST structures are also discussed. The results show that the additional rail stress is small and the CST structure has a high safety factor under the measured temperature load. The rail expansion device can be cancelled when CST is adopted on the long span bridge. Beam end rotation caused by temperature gradient and vertical load will have a significant effect on the rail stress of CST. The additional flexure stress should be considered with the additional expansion stress simultaneously when the rail stress of CST requires to be checked. Both the maximum sliding friction coefficient of sliding layer and cracking condition of concrete plate should be considered to decide the arrangement of connecting components and the ultimate expansion span of the bridge when adopting CST.

장대레일 재설정 방법 개선 연구 (A study on the refined resetting for the continuous weleded rail)

  • 김우진;정찬묵;민경주
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.386-394
    • /
    • 2007
  • Due to the transportability problems, long rail shall be from base rail unit, which is normally 100m for regular rail and 300m for high speed rail. After these rail units are transported from the fabricator to the site, the field weld would be performed.axial stresses in the long rail is mainly from the temperature differences at various locations the long rail. Also the gaps between each welds cause secondary axial stresses in the rail. In addition to these, re-welds the fractured rails, rail buckling, irregular rail vibration, rail twist also result innonuniform axial stresses in the rail. To obtain the rail buckling stability, the rail stresses shall be released due to the resetting of CWR. Traditionally two resetting of CWR methods have been applied, the one is rail heater and the other is rail tenser. these methods, the latter has been recommended because it has less limitation in the rail length and it is easier to minimized the force differences. But even in this method, the calculation is cumbersome and is not easy to find out the rail stress distribution itself.refined methodsxial stress resetting in the long rail is studied and this study be easily applied in the real construction. From this approach, more rational rail maintenance system can be expected.

  • PDF

레일연마를 고려한 장대레일의 피로수명 평가 (The Fatigue Life Evaluation of CWR based on the Rail Grinding)

  • 공선용;성덕룡;박용걸
    • 대한토목학회논문집
    • /
    • v.35 no.5
    • /
    • pp.1191-1198
    • /
    • 2015
  • 본 연구에서는 국내 일반철도 새마을호 동력차 및 궤도조건을 고려한 차량/궤도 상호작용해석을 수행하였다. 레일표면요철에 따른 레일휨응력을 분석하였고, 레일 휨응력예측식을 도출하였다. 또한, 일반철도 레일강의 S-N선도를 이용한 피로해석을 수행하였다. 파괴확률에 따른 레일피로수명을 산정하였고, 레일연마에 따른 레일표면요철 제거 및 레일휨응력 저감효과를 고려한 레일피로수명 평가를 수행하였다. 따라서, 국내 일반철도에서 레일연마 시행방법에 따른 레일피로수명을 평가하여 제시하였다.

Calculating the Contact Stress Resulting from Lateral Movement of the Wheel on Rail by Applying Hertz Theory

  • Ashofteh, Roya Sadat
    • International Journal of Railway
    • /
    • v.6 no.4
    • /
    • pp.148-154
    • /
    • 2013
  • This article has tried to review the maximum contact stresses in the contact area of the wheel and rail as a result of lateral movement of the wheel on rail by taking advantage from Hertz theory. Since wheel movement on rail is accompanied by lateral movement due to wheel profile conisity, so the contact point of wheel and rail is not constant and the contact stresses are therefore changeable in every single moment. Since the shape of rail profile and rail inclination, wheel diameter and the mechanical properties of the wheel and rail are effective on the stresses of contact area, these parameters have been studied by applying Hertz theory. This article aims to calculate the contact stresses in different parts on the wheel surface by using Hertz theory.

중회귀분석을 통한 콘크리트궤도 레일 휨응력 예측식 (The Prediction Equation for Bending Stress of Rail in Concrete Track by the Linear Multiple Regression Analysis)

  • 성덕룡;임형준;이동욱;김박진;박용걸
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.315-323
    • /
    • 2010
  • 장대레일 교체주기는 자갈궤도 레일두부 표면요철과 레일 휨피로의 상관관계 분석을 통해 산정되었다. 본 연구에서는 국내 도시철도(서울메트로) 콘크리트궤도에서 레일두부 표면요철량에 따른 레일 휨응력을 측정하였다. 또한, 콘크리트궤도 레일두부 표면요철, 속도와 레일 휨응력의 상관관계를 분석하였다. 결론적으로, 중회귀분석을 통해 운행속도(U), 표면요철(v, w)에 따른 레일 휨응력(Y) 예측식을 도출하였다. 본 연구결과는 콘크리트궤도 장대레일 교체주기를 수립하기 위한 기초데이터로 활용이 가능할 것이다.

  • PDF

현장측정을 통한 노후 레일의 피로수명 평가에 관한 연구 (A Study on Estimation of Fatigue Life of Aged Continuous Welded Rail using the Field Test)

  • 공선용;성덕룡;김준형;박용걸
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.352-364
    • /
    • 2007
  • It is essential to reduce track maintenance costs and to extend the periodic replacements of continuous welded rails based on accumulated passing tonnage. As recently train load decrease and rail joints wear down less, the periodic replacements of continuous welded rails can be extended. There are many kinds of rail damage like squat, head-check and corrugation. These can be taken nondestructive or naked eye test. So the periodic replacements of continuous welded rails based on accumulated passing tonnage were examine with focusing on a crack of rail bottom of continuous welded rail. Therefore, this study measure dynamic response of track by metro train load, it compute impact coefficient and track spring coefficient for estimating a condition of actual track system. Also, it is converted the measured stress waveform into stress frequency histogram by the rain-flow counting methods, and then the equivalence of stress is calculated. As apply s-n curve of a new welded rail, accumulated fatigue damage ratio of laid rail and remaining service lives is estimated. This study suggest a plan of the periodic replacements of continuous welded rails based on accumulated passing tonnage classified by the types of track system.

  • PDF

ADAMS/Rail과 ADAMS/Durability를 이용한 철도차량의 동응력 해석 (Dynamic stress analysis of the railway vehicle using ADAMS/Rail and ADAMS/Durability)

  • 조연호;이강운;박길배;최중호
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.573-578
    • /
    • 2004
  • Rotem has chosen ADAMS/Rail as the next generation analysis tool, to improve the capability and accuracy of the analysis ability. The dynamic performances of the railway vehicle, which is designed and manufactured by Rotem, have been analyzed and simulated using ADAMS/Rail. In this paper, Dynamic stress of bogie frame on running track is analyzed and compared with the data of real vehicle test. It is performed using ADAMS/AutoFlex and ADAMS/Durability.

  • PDF

레일의 라체팅에 미치는 접촉응력 및 열응력에 대한 해석적 연구 (An Analytic Study on the Contact Stress and Thermal Stress of Rails)

  • 구병춘;유원희
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.767-774
    • /
    • 2007
  • Even though a constant repeated load is applied, plastic deformation may cumulate. This kind of behavior is called ratcheting. Ratcheting may lead to cracks and finally to failure of the rail. Usually ratcheting occurs on high rails in curves. Ratcheting is influenced by residual stresses, wheel-rail contact stresses, thermal stresses due to wheel/rail rolling contact, shear strength of the rail, strain hardening behavior, etc. In this study, contact stresses and thermal stresses are examined. It is found their value is considerable compared to the maximum contact pressure.

  • PDF

철도차량용 휠과 레일의 형상설계에 관한 연구 (A Study on the Shape Design of Wheel-Rail for Rolling Stock)

  • 성기득;양원호;조명래;허성필
    • 대한기계학회논문집A
    • /
    • v.23 no.11
    • /
    • pp.2033-2039
    • /
    • 1999
  • One of the main causes of severe wear or crack initiation in wheel and rail is the contact stress due to wheel-rail contact. In this paper, the shape design based on more reasonable contact stress analysis rather than a general Hertzian contact theory is investigated in order to reduce the contact stress. The optimal design is performed using the simple 2-D finite element model and its results are verified by 3-D finite element analysis.

콘크리트도상(STEDEF)의 선로조건을 고려한 레일휨응력 예측과 피로수명 산출 (Evaluation of Rail Fatigue and Bending Fatigue Considering Concrete Track Condition)

  • 이수형;강유송;박용걸
    • 한국철도학회논문집
    • /
    • v.20 no.5
    • /
    • pp.658-667
    • /
    • 2017
  • 철도는 여객을 수송하기 위한 수단으로, 열차의 주행안정성과 탈선방지 등 절대적인 승객의 안전을 확보하는 것이 중요하다. 철도에서 사용하고 있는 레일은 여객을 안전하게 수송하는데 있어 가장 중요한 역할을 담당하는 궤도의 구성품이며, 안전을 위하여 레일의 피로, 파괴에 대한 신뢰성 확보가 엄격히 요구되고 있다. 본 논문에서는 콘크리트 궤도(STEDEF)의 현장측정을 통해 레일표면요철과 레일휨응력이 선형적인 상관관계가 있음을 확인하였으며, 레일표면요철, 궤도지지강성, 열차속도에 따른 레일의 휨응력예측식을 제시하였고, 실내 피로시험을 통해 S-N선도를 도출하여 레일 피로수명을 산정하였다.