• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.207-212
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• 2002

The actual buckling of the railroad track structure is suspected to be a complex interaction between the vertical, lateral and torsional modes. To make the analysis tractable, however, most studies restrict themselves to either the vertical or the horizontal plane. Based on a comprehensive and realistic three-dimensional track model developed in the previous study, three dimensional buckling analysis of CWR track subjected to temperature load was performed. Using the study on buckling temperature and mode, sensitivity of track components such as tie spacing, ballast resistance, stiffness of pad-fastening system and rail size were investigated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2464-2472
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• 2011

열차주행이 고속화 되고 콘크리트궤도가 건설되고 있는 가운데 레일 체결장치는 저탄성화로 전달하중, 소음, 진동 등을 저감 하려는 추세이다. 따라서 저탄성패드의 적용은 궤도전체의 내구성과 안정성에 미치는 영향이 크다고 할 수 있다. 본 연구에서는 선행연구에서 다룬 패드스프링계수별 정적해석과 실물반복재하시험에 이어 동적응답해석을 추가적으로 수행하였다. 열차바퀴를 실물로 모델링하여 레일위에서 직접 주행시킴으로서 이 때 발생하는 궤도각부의 변형특성을 비교 분석하여 저탄성패드의 스프링계수에 따라 노반으로 전달되는 하중의 저감 효과를 검토하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.432-441
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• 2007

Any track system needs major changes of its components during its life. The most economical solution is, if possible, to make all components reach their life limit during the major track rehabilitation operation. Usually, the rail does a role as the driving component for the objective: its life-time is equivalent to around 500 million tons of traffic on high speed lines. On the KTX line with 110 trains per day, this would correspond to around 16 years, which is probably too long for the elastic pads of a concrete slab track. The most economical solution should be to change them at an intermediate step of 8 years, without changing the rail, and then to change both the rail and elastic pad at 16 years intervals (some rail changes on the South East TGV line in France began 15 years after service opening at 260 km/h, but recent rails have better characteristics).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.842-847
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• 2004

This study presents the minimum spring stiffness of resilient track pad considering the safety of running train. A nonlinear static 3-D finite element is used for the modeling of railway superstructure, especially for the reflection of nonlinear resistance of rail fastening system. Moreover, ballast is considered as an elastic foundation. As the input load, eccentric wheel and lateral force are used and they are derived from ' Lateral-force/Wheel-load Estimation Equations '. Analysis results are compared with following two values : allowable lateral displacement of rail head (derived from the geometrical derailment evaluation of wheel/rail) and operation standard value (derived from the field test results of track).

• 한국전기전자재료학회논문지
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• 제30권6호
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• pp.381-386
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• 2017

A railway track generates severe levels of vibrations. In order to reduce these vibrations and to provide structural stability, various rail pads, mats, etc., are used for vibration protection. In this study, a specially designed rail pad was developed to reduce vibration and to generate electric power simultaneously, that is, by using the vibrations generated by railway cars on the track. The newly developed rail pads were tested to evaluate the characteristics of electric power by investigating the generated voltage and the current levels and patterns. In addition, we proposed an optimal laminated structure and adhesive by comparing the voltage generated by each type of adhesive required for optimal adhesion of the rail pad and the piezoelectric device.

• 한국철도학회논문집
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• 제19권4호
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• pp.498-505
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• 2016

간선철도 고속화에 대비하여 유지보수를 고려한 최적 자갈도상 궤도구조 정립을 위한 기초연구로 국내 자갈도상 궤도 구성품들을 조합한 실대형 시험을 실시하여 궤도 침하 특성을 분석하였다. 실대형 시험 결과 유지보수 저감을 위해서는 패드만을 고탄성화 하였을 경우의 효과는 미비하였으며, 패드의 고탄성화와 더불어 침목 중량화 또는 침목 중량화 및 도상두께를 증가 하였을 경우에 그 효과가 크게 나타났다. 간선철도 고속화에 따른 최적의 자갈도상 궤도구조는 초기 건설비와 본 논문에서 제시한 궤도 침하 특성에 따른 유지보수비를 고려한 경제성 분석을 통해 최종 정립되어야 할 것이다.

• Structural Engineering and Mechanics
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• 제83권6호
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• pp.709-727
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• 2022

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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.419-431
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• 2007

The track and rail surface geometry is of prime importance on the requirement for track dynamic stiffness, particularly for the speed of 350 km/h, for which both the requirement for fatigue and tensile strength limits require a lower stiffness than 100 kN/mm, which is near the value for ballasted track. However, the track quality has been considered as being the same for 350 km/h as that for 300 km/h, and based on ballasted track, and the track geometry may be kept in better condition with a slab track(probably more similar to the medium quality track geometry of ballasted track). In conclusion, under the condition that the track geometry quality provided by the concrete slab system is fairly good, and that the required maintenance is applied to the rail surface, there would be no safety risk if the fastening system point stiffness reaches 160 kN/mm for 300 km/h operation, and 110 N/mm at 350 km/h.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.763-768
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• 2004

CWR(Continuous Welded Rail) has many advantage over the conventional jointed rail track. The use of CWR track not only reduces the track maintenance cost, but increase the life cycle of track components. As the use of CWR increases in track structures, derailing disasters associating with track buckling also increase in great numbers due to high compressive thermal stress. Despite the importance, the number of studies relevant to the instability is quite limited. In this paper, It considers the contribution of rail-pad-fastener resistance, uplift of tie and nonlinear analysis. Influence of various track components on CWR track temperature and mode shape were characterized.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1056-1064
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• 2008

It is estimated that the running of locally-developed next generation High Speed Trains with maximum speed of 400km/h will help to deteriorate track components. It was presented rail defect coding system in UIC 712R includes the definitions of damage types of rail, maintenance procedures, and etc to detect and maintain. It is necessary to make a track maintenance manual determining track maintenance periods using the standardization of damage types of track components such as: sleeper, fastener, elastic pad. In this paper, the damage types of high speed track components are investigated by referring domestic and foreign literatures. And then the damage types of rail given in UIC 712R is reclassified more particularly and classified damage types of track components using internal high speed railway. In conclusion, this paper suggests standardization for damage types of track components on internal high speed railway.