장대레일 궤도의 안정성에 미치는 체결장치의 실험적 연구

김정훈(Kim Jung Hun),한상윤(Han Sang Yun),임남형(Lim Nam Hyoung),강영종(Kang Young Jong) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

Until now, the railway has been constructed using track with jointed rails of relatively short lengths to allow thermal expansion in hot summer months. These joints weaken the track structurally and increase track maintenance cost and power consumption of the running train. The CWR(Continuous Welded Rail) Track is the solution of these drawbacks. Although the CWR track not only reduces the track maintenance cost but also increases the life cycle of track components, the stability of the track is highly affected by change of temperatures and vehicle load. A three dimensional nonlinear analysis which considers rail, fastening system and tie has been performed to understand structural behavior of the CWR track. In this case, the translational and rotational stiffness values of fastening system have not been studied. The fastening system makes ties and rails connect. In this study, the stiffness values of various types of fastening systems which consist of clips, rail-pads and insulators are determined by the experiment. The experimental results of the fastening system are compared with the results of parametric study that is performed to investigate the sensitivity of fastening system on stability of CWR track.

Effects of vertical stiffness of rail fastening system on the behavior of the end regions of railway bridges with slab tracks

Deokyong Sung,Sukhoon Pyo,Seongkyu Chang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.2

A railway bridge with slab track is subjected to end rotations because of the deflection of the girder during train operation. At the ends of a slab track, the end rotation of the bridge girder causes uplift deformation of the slab track, and leads to compressive stresses in the rail fasteners. In this study, a prototype bridge consisting of one span of a girder and one span of an abutment along with a slab track was constructed, and the uplift and compressive forces generated in the rail fastening system were experimentally analyzed. To effectively analyze the experimental results using a numerical method, a series of finite element analyses were performed considering the nonlinear nature of the rail fastening system. A comparison between the experimental and analytical results indicated that the higher the stiffness of the rail fastening system, the greater the uplift and compressive forces. In addition, a nonlinear model provided better correlation with the experimental results than a linear model. Therefore, when reviewing the serviceability of the rail fastening system at railway bridge ends, an adequate finite element model considering the uplift and compressive forces in the rail fastening system should be used.

Effect of nonlinearity of fastening system on railway slab track dynamic response

Javad Sadeghi,Mohammad Seyedkazemi,Amin Khajehdezfuly 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.6

Fastening systems have a significant role in the response of railway slab track systems. Although experimental tests indicate nonlinear behavior of fastening systems, they have been simulated as a linear spring-dashpot element in the available literature. In this paper, the influence of the nonlinear behavior of fastening systems on the slab track response was investigated. In this regard, a nonlinear model of vehicle/slab track interaction, including two commonly used fastening systems (i.e., RFFS and RWFS), was developed. The time history of excitation frequency of the fastening system was derived using the short time Fourier transform. The model was validated, using the results of a comprehensive field test carried out in this study. The frequency response of the track was studied to evaluate the effect of excitation frequency on the railway track response. The results obtained from the model were compared with those of the conventional linear model of vehicle/slab track interaction. The effects of vehicle speed, axle load, pad stiffness, fastening preload on the difference between the outputs obtained from the linear and nonlinear models were investigated through a parametric study. It was shown that the difference between the results obtained from linear and nonlinear models is up to 38 and 18 percent for RWFS and RFFS, respectively. Based on the outcomes obtained, a nonlinear to linear correction factor as a function of vehicle speed, vehicle axle load, pad stiffness and preload was derived. It was shown that consideration of the correction factor compensates the errors caused by the assumption of linear behavior for the fastening systems in the currently used vehicle track interaction models.

레일체결장치 지지강성이 차륜-레일 접촉력에 미치는 영향 분석

황성호(Sung Ho Hwang) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.10

차량을 설계함에 있어 사용되고 있는 다물체 동역학 프로그램들은 보통 궤도를 단순화하여 모델링하기에 레일은 움직이지 않는 강체로 가정을 한다. 하지만 레일체결장치의 지지강성에 따라 레일의 움직임을 고려할 경우 차륜-레일의 접촉력은 그렇지 않은 경우에 비해 다른 양상으로 나타난다. 따라서 본 논문에서는 이러한 영향을 고려할 수 있는 in-house 프로그램을 통해 레일체결장치의 지지강성에 따라 차륜-레일의 접촉력 변화를 분석하고자 한다. In order to make the track model simple, the normal multibody dynamics programs assumes that the rail does not move as if it is rigid. But when the supporting stiffness of rail fastening system is considered in the model, the wheel-rail contact force shows some other pattern compared with the case of rigid rail. Therefore this paper analyze the variation of wheel-rail contact force according to railpad’s stiffness by using in-house program that enables the rail to move vertically and laterally.

체결장치의 종방향 저항 특성을 반영한 교량상 콘크리트궤도의 종방향 저항력 산정

민경환(Min, Kyunghwan),윤경민(Yun, Kyungmin),박종찬(Park, Jongchan),임남형(Lim, Namhyoung) 한국방재학회 2018 한국방재학회논문집 Vol.18 No.5

궤도-교량 상호작용 검토 시 궤도의 종방향 저항력은 매우 중요한 인자이다. 하지만 다양한 설계기준에서 궤도-교량 상호작용 해석을 위한 교량상 콘크리트궤도의 종방향 저항력은 하나의 선도로 제시하고 있기 때문에 실제 부설되는 체결장치의 저항력을 고려하기 어렵다. 본 연구에서는 실내 체결장치 실험을 통하여 궤도-교량 종방향 상호작용 검토시 안전측 설계가 가능한 저항력을 산정하였다. 이를 위하여 실내 저항력 실험을 수행하였으며, 실험을 통하여 수직하중 재하 시 저항력은 수직하중의 증가에 따라 선형으로 증가하는 것을 확인하였다. 그리고 수직하중에 의한 저항력 증가를 고려하기 위한 관계식을 만들어 저항력의 신뢰 범위를 산정하였다. 또한 신뢰범위내의 저항력을 고려하여 궤도-교량 상호작용 해석을 수행하고 결과를 분석하였다. 신뢰범위 내에서 상한값을 사용한 경우에 궤도-교량 종방향 상호작용 검토시 안전측 설계가 가능함을 확인하였다. The longitudinal resistance of a railway track is one of the most important factors indicating the track-bridge interaction (TBI). However, it is difficult to consider the actual resistance of an installed fastening system of a rail because the longitudinal resistance of the concrete track on the bridge for analyzing TBI is presented as a single resistance-displacement curve in design standards. In this study, the resistance that can satisfy the design requirements from the point of view of safety was calculated through experiments of the fastening system of rails. For this purpose, laboratory experiments were performed, and it was confirmed that the resisting force increases linearly with the vertical load. Further, the confidence interval of the resistance was calculated by establishing a relation that accounts for the increase in resistance due to the vertical load. Moreover, the TBI analysis was performed considering the resistance within the confidence interval, and the results were analyzed. It is thus confirmed that safe design is possible when the upper limit of the resistance value used is within the confidence interval.

고속철도 콘크리트 궤도용 레일체결장치 성능 검토

박옥정(Ok-Jung Park) 한국정밀공학회 2013 한국정밀공학회 학술발표대회 논문집 Vol.2013 No.10월

인천공항 철도용 고탄성 레일체결장치 성능 평가

박옥정(Ok-Jung Park) 한국정밀공학회 2013 한국정밀공학회 학술발표대회 논문집 Vol.2013 No.10월

도시철도 방진체결장치 종방향 저항력 시험에 관한 연구

박옥정(Ok-jeong Park),임정순(Jung-Soon Lim) 한국정밀공학회 2009 한국정밀공학회 학술발표대회 논문집 Vol.2009 No.6월

굽힘파 전파 특성을 이용한 레일체결장치의 구조 결함 진단

박정원(Jeongwon Park),박준홍(Junhong Park) 한국비파괴검사학회 2014 한국비파괴검사학회지 Vol.34 No.1

굽힘파 전파 특성을 이용하여 지지강성을 도출하고 이를 이용한 레일체결장치의 결함 검출 시험법을 제안하였다. 점탄성 패드로 지지되고 체결장치로 고정된 레일의 진동 응답은 주파수에 따라 지지단 동특성에 크게 영향을 받는다. 체결장치에 결함이 발생할 경우에는 구조적인 불연속성으로 인해 굽힘 파동의 전파 특성이 변화하게 된다. 이러한 변화를 감지하기 위해서 전달함수법을 이용해 주파수에 따라 변화하는 레일 지지단 동특성을 측정하였다. 연속 스프링으로 지지된 레일 응답으로부터 예측한 레일의 보존에너지를 이용해 결함에 대한 파동 전파의 민감도를 해석하였다. 민감도 해석 결과와 동적지지강성 변화를 측정하여 손상지수를 계산하고 결함 위치를 추정하였다. An experimental method based on flexural wave propagation is proposed for identification of structural damage in rail fastening systems. The vibration of a rail clamped and supported by viscoelastic pads is significantly influenced by dynamic support properties. Formation of a defect in the rail fastening system induces changes in the flexural wave propagation characteristics owning to the discontinuity in the structural properties. In this study, frequency-dependent support stiffness was measured to monitor this change by a transfer function method. The sensitivity of wave propagation on the defect was measured from the potential energy stored in a continuously supported rail. Further, the damage index was defined as a correlation coefficient between the change in the support stiffness and the sensitivity. The defect location was identified from the calculated damage index.

실내 실험을 통한 교량상 콘크리트궤도의 종방향 저항력 산정방법에 관한 연구

민경환,윤경민,박종찬,임남형 한국철도학회 2018 한국철도학회논문집 Vol.21 No.5

The lower longitudinal resistance of a track on a bridge is, the smaller is the interaction between the trackand the bridge. Therefore, compared to an embankment section, when installing a concrete track on the bridge, a lowresistancerail fastening system is applied. However, since the resistance curve of track is presented as a single curve inthe design standards, it is necessary to propose a method of calculating the resistance that can reflect the resistance ofthe fastening system applied in the field. In this study, a method of calculating the design resistance was proposedthrough laboratory experiments on a rail fastening system. For this purpose, laboratory tests were performed and themean and standard deviation of the resistance were calculated. Using the results, a random variable 3 was extracted andmodified coefficients proposed in the Eurocode were proposed. Through our results, it can be possible to estimate thedesign resistance, which can be economically designed for safety.