• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.401-406
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• 2019

The three-dimensional precision numerical analysis was performed using the finite element model applied with the railway track model consisting of rails, sleepers, and track elastic springs(ballast, rail pad). As a result of analyzing the track deformation level of the existing tracks due to the excavation work adjacent to the railway facilities, it was found that the track irregularity evaluation criteria (allowed values) of both conventional and high-speed railways lines were satisfied. Based on the numerical analysis using the track model, it was analyzed that the results of the prediction of the track irregularity due to the excavation work and the level of the track deformation occurring at the actual site could be approximated as closely as possible.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1077-1092
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• 2007

The structural analysis model for estimate of load carrying capacity of railway bridge on service line is important to determine safety of bridges in service, we need to take response of bridge exactly, applying analysis model similar to the real railway bridge most. Track structure which is to distribute loads and decrease vibrations occurred from running train is constructed on the railway bridges. And it is important factor which should be considered to understand exact dynamic and static responses of bridge. But track structure is currently classified as a none structural members in the structural analysis model for estimating load carrying capacity of railway bridge and not considered in analysis model. That's the reason it is difficult to understand exact behavior of bridges. Therefore, the major objective of this study is to develop an analytical track-bridge model which is similar to real railway bridges considering track structure for safety assessment of railway bridge on service line to be effectively done.

• 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.

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.45-51
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• 2016

The purpose of this study is to investigate the influence of train-induced end rotation of simple supported track girder on the performance of a direct fixation track system (DFTS) in Yeongjong grand bridge. In this study, the influences of deflection of a DFTS and track girder on dynamic rail-track girder interaction forces for the track girder ends currently employed in airport express lines were assessed by performing field tests using actual vehicles running along the service lines. Therefore, the dynamic displacement of rail and track girder and the fastener stress on the center and ends sections of DFTS were measured for two different trains (AREX and KTX) running in Yeongjong grand bridge. A three-dimensional finite element analysis (FEA) model using the time-history function based on the design wheel load was used to predict the train-induced track and track girder displacement, and the FEA and field test results were compared. The analytical results reproduced the experimental results well within about 3-7% difference in the values. Therefore, the FEA model of DFTS on track girder is considered to provide sufficiently reliable FEA results in the investigation of the behavior of DFTS. Using the analytical and experimental results, the influence of train-induced end rotation of simple supported track girder on the interaction behavior of rail and track girder installed on a simple supported track girder ends, i.e., upward displacement of rail-track girder and the fastener stress, was investigated. It was found that the train-induced end rotation effect of track girder was not significantly affected by the upward displacement of rails and the fastener stresses of track girder ends. Further, the interaction behavior of rail and track girder were similar to or less than that of the general railway bridge deck ends, nevertheless the vertical displacement of track was higher than that of conventional DFTS on the general railway bridge. From the results, the dynamic responses of the DFTS on track girder ends were not significantly affected by the safety and stability of DFTS ends.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1299-1305
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• 2006

In this paper, the objective is an evaluation of economics using Life Cycle Cost(LCC) analysis for the ballasted track and the concrete track. However, since the absence of reliable data on maintenance activities, the degree of a reliability about the results of the LCC analysis is insufficient yet. In order to remedy the problems, we surveyed a professional research group for an approximate estimation which can be represented a degree of maintenance through a application of examples. Hereby we found that it is possible to expect the retrenchment of cost using preventive maintenance management. Moreover we proposed appropriate and economical restrictions between track structures.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2487-2492
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• 2011

At high rail temperature above the neutral temperature, high compressive axial stresses will occur in the rails. High thermal axial force and vehicle loads cause the track to shift in a lateral direction and the formation of track geometry imperfections (track irregularity). When the thermal stress level and track irregularity with vehicle load reach a critical value, the track loses stability. In many studies, the stability of CWR tracks is analyzed. However these studies are only considered in temperature load. The main objective of this investigation was to estimate a new, comprehensive, realistic, the stability of CWR tracks considering wheel load. The ballast resistance is changed by wheel load. When the wheel load is applied, rails and ties are moved upward or downward. In this case the friction between ties and ballasts is decreased or increased. In this study the change of the ballast resistance of each tie was applied to the nonlinear analysis of CWR tracks.

• Computers and Concrete
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• v.21 no.3
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• pp.239-248
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• 2018

This study developed and investigated a precast slab track system partially reinforced with glass fiber reinforced polymer (GFRP) rebars in the transverse direction, which mitigated the loss of track circuit current by reducing magnetic coupling between the rails and steel reinforcements. An electric analysis was conducted and the results of the analysis verified that the GFRP rebars mitigate the reduced current strength produced by electro-magnetic induction. In the study, a three-dimensional finite element method and flexural experiments were used to study the mechanical behavior of the proposed slab track.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.20-27
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• 2001

A variable configuration tracked vehicle(VCTV) is developed to reduce turning energy and improve climbing ability for stairs. This mechanism has four track T-type frames. By changing the driving direction, each track T-type frame rotates to minimize the contact area with ground. It also has better performance than other VCTV in energy consumption of turning. Futhermore this mechanism is more stable than other VCTV on the rough terrain. When climbing stairs, each track T-type frame rotates to obtain a front attack angle and keep stability on steep stairs. The design parameters of components of track T-type frames are optimized to enhance the performance of climbing stairs. Performance indices include a stable angle, a climbing ability, a height of the vertical obstacle. In case that the overall length of the mechanism is 0.2m, it is required that the radius of the wheels should be 5mm and the length track contacted with he ground should be 0.09m to climb higher and steeper stairs.

• Journal of the Korean Society for Railway
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• v.4 no.4
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• pp.138-146
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• 2001

For the purpose of the effective maintenance of surface irregularities of rail, this paper investigates the rail service life to a bending fatigue failure of welding parts of rail on the slab track by the structures laboratory testing to derive S-N curves, a GTDAP(General Track Dynamic Analysis Program) to calculate the stresses and a modified Miner's rule to predict a fatigue life. The useful guides for maintenance of rail welded parts on the slab track are proposed in terms of a grinding period and the depth of rail surface irregularities. This study also proposed the guides for maintenance of rail welded part on the ballast track. The effects of fatigue service lives are compared one another.

• Journal of the Korean Society for Railway
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• v.9 no.3 s.34
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• pp.298-304
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• 2006

An active application of concrete track is being expected for the future constructions of Korean railroad. For the successful concrete track construction and design in earthwork areas, the roadbed behavior should be reasonably estimated using the proper analysis method. In this paper, behaviors of concrete track on the reinforced roadbed constructed with the standard stiffness and depth were estimated thorough numerical analyses and field measurements. A three dimensional finite difference method was employed to model the concrete tracks and subground. The settlement and vertical pressures caused by train load were estimated by the numerical method and compared with the field measurement results. The bearing characteristics of roadbed were presented and the proper method for the analysis of concrete track was proposed.