• Interaction and multiscale mechanics
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• v.5 no.1
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• pp.1-12
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• 2012

Considerable longitudinal rail forces and displacements may develop in continuous welded rail (CWR) track on long-span bridges due to temperature variations. The track stability may be disturbed due to excessive relative displacements between the sleepers and ballast bed and the accompanied reduction in frictional resistance. For high-speed tracks, however, solving these problems by installing rail expansion devices in the track is not an attractive solution as these devices may cause a local disturbance of the vertical track stiffness and track geometry which will require intensive maintenance. With reference to temperature, two actions are considered by the bridge loading standards, the uniform variation in the rail and deck temperature and the temperature gradient in deck. Generally, the effect of temperature gradient has been disregarded in the interaction analysis. This paper mainly deals with the effect of temperature gradient on the track-bridge interaction with respect to the support reaction, rail stresses and stability. The study presented in this paper was not mentioned in the related codes so far.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.126-131
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• 2014

This paper is concerned with a track management method for a naval combat system which receives the tracks information from multi-sensors and multi-tactical datalinks. Since the track management of processing the track information from diverse sources can be formulated as a data fusion problem, this paper will deal with the data fusion architecture, track association and track information determination algorithm for the track management of naval combat systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.163-168
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• 2007

A light railway operationis an effective means to solve a traffic problem of the city however, noise and vibration is pollution happened. This paper studied noise and vibration pollution of a light railway operation in order to let a decrease. The study range was only track condition and civil engineering structure condition. The way how we decrease noise and vibration in a protection vibration track, ballasted track, non-ballasted track, floating track trends was devoted is long rail laying, low vibration track lying. It was the most economic that the examination results track section a complement, and it was proved that a certain way.

• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.89-94
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• 2016

The objective of this study was to estimate the dynamic behavior of a personal rapid transit(PRT) track system using a rail of rectangular tube section and a rail joint of sliding type, and to compare the results with the normal rail and rail joint of a PRT track system by performing field measurements using actual vehicles running along the service lines. The measured vertical displacement of rail and sleeper, and vertical acceleration of rail for the normal rail and rail joint section were found to be similar, and the rail joint of sliding type satisfied the design specifications of the track impact factor for a conventional railway track. The experimental results showed that the overall dynamic response of the rail joint were found to be similar to or less than that of the normal rail, therefore the rail joint of sliding type for PRT track system was sufficient to ensure a stability and safety of PRT track system.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.163-166
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• 2003

Since the track pin is subjected to large transverse track tension from the track link, conventional track pins for high mobility vehicles are usually made of high strength steel, which increases the weight of tracked vehicles due to the high density of steel. In this paper, several composite materials were employed for track pin design to reduce weight of track pin as well as to enhance the fatigue life of rubber bushings. Especially the effects of shear stiffness of the composites on the life of rubber bushing were investigated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.443-451
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• 2001

This paper addresses an on-line scheduling method for track systems in semiconductor fabrication. A track system is a clustered equipment performing photolithography process in semiconductor fabrication. Trends toward high automation and flexibility in the track systems accelerate the necessity of the intelligent controller that can guarantee reliability and optimize productivity of the track systems. This paper proposes an-efficient on-line scheduling method that can avoid deadlock inherent to track systems and optimize the productivity. We employ two procedures for the on-line scheduling. First, we define potential deadlock set to apply deadlock avoidance policy efficiently. After introducing the potential deadlock set, we propose a deadlock avoidance policy using an on-line Gantt chart, which can generate optimal near-optimal schedule without deadlock. The proposed on-line scheduling method is shown to be efficient in handling deadlock inherent to the track systems through simulation.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.498-503
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• 2005

In this paper, an experimental study is carried out to analyze the vibration characteristics of components of the ballast track and the slab track layed in HSL tunnels. According to vibration level test of ballast tracks and concrete tracks on HSL, the vertical vibration level of rails on concrete tracks is 6.2dB more than that on ballast tracks, and especially on $50{\sim}80Hz$ frequency band, the difference is more than 6dB. The orther track components according to track type are appeared to be smaller on the slab track than on the ballast track. Regarding car body vibration, 80Hz component, which was not remarkable while running on open tracks, is considerably amplified in tunnels where concrete tracks are laid.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.351-357
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• 2007

The transition zone between railway embankment and structures, or different track types is known to be an area in which problems often arise and where extra care needs to be taken with maintenance. Differences in track stiffness have dynamic effects and these increase the force in the track and the extent of deformation. In this study, the criteria for the change ratio of track stiffness along transition area, and proper transition length are presented through train/track interaction analyses. Those are derived on the basis of permissible limitations of train and track performances such as rail stress, uplift force of fastener, reduction of dynamic wheel force, and acceleration of car body. A feasible method of evaluation of track stiffness which is necessary when a designer reviews whether the criteria are satisfied or not is also presented.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.256-260
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• 2010

It has been proved that precast slab track has advantage of rapid construction speed and good quality compared to in-situ concrete slab track. A korean precast slab track, which is named as a K-PST, was developed and had been installed on the embankment and explored on the air. The developed track system consists of precast track panel and underpouring layer which is made of cement-asphalt mortar. Consequently, poor filling of underpouring layer directly could affect on the long-term performance of the track system. As a preliminary study, the effect of the poor infilling of the underpouring in precasst slab track system on structural behavior was investigated through FEM analysis.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.671-679
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• 2010

The construction of concrete track for the first time in Korea gives lots of meanings to civil engineering in various aspects. Settlement level needs to be kept minimal for the safety of the track. Concrete track has different structural characteristics comparing to conventional ballast track, so load distribution in concrete track is also different. Since it is the first time to build concrete track, there are very few experience and data available on the subject. Therefore it is important to evaluate how much load is transferred to the ground due to the running vehicle in concrete track and to determine the optimal thickness of layers. In this research, 9 individual earth pressure cells were installed at OOOk930 site in 2nd stage of Kyungbu high speed railway during under construction. The in-situ pressure data were measured at each layers during pump-car and locomotive were moving on the high speed railway surface.