• Proceedings of the KSR Conference
• /
• 1999.11a
• /
• pp.455-462
• /
• 1999

Tn this paper. a numerical method for the system analysis of the slab track is presented. In the model rail is considered to have a distributed mass and to be supported by sleepers discretely on slab. The slab supported by discrete slab pads- isolators Put on floor is modelled by finite beam elements The system analysis for the same type floating slab laid in Puchon station is carried out using the developed program. Then the numerical results are compared with system requirements for slab track.

• Steel and Composite Structures
• /
• v.24 no.1
• /
• pp.113-128
• /
• 2017

This paper highlights a study undertaken on the free vibration of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an evolvement from the slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both eigenfrequencies and eigenmodes have been extracted using the Lanczos method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

• Steel and Composite Structures
• /
• v.25 no.4
• /
• pp.427-442
• /
• 2017

This paper presents unprecedented damped oscillation behaviours of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an innovative slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both undamped and damped eigenfrequencies and eigenmodes have been extracted using the Lancsoz method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.680-685
• /
• 2005

An active application of concrete track is being expected for the future constructions of Korean railroad. For the successful concrete track construction in earthwork areas, proper reinforced subgrades, which effectively distribute train loads to subground, should be installed. In this paper, behaviors of concrete track on the reinforced subgrade with the standard stiffness and depth were investigated through numerical analyses. The appropriateness of the reinforced subgade was evaluated by analyzing the distributions of the settlements and vertical stress beneath the concrete slab.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.201-207
• /
• 2007

At an early design stage of rail track, dynamic analyses using a standard vehicle model of ADAMS/Rail are employed. In the real field, it is very difficult to find an optimal solution on the designing of rail track considering future operating vehicles because the construction of rail track should be done in the advance of vehicle selection and operation. Using a standard vehicle model of ADAMS/Rail, however the better selection among designed rail tracks is possible by comparing the dynamic analysis.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.10
• /
• pp.1458-1464
• /
• 2013

This paper proposed a new real time catenary impedance estimation technique using synchronized power data from the measured data of operating vehicle and substation for catenary protective relay and fault locator setting. This paper presented estimation equation of catenary impedance using synchronized power data between substation and vehicle of AT feeding system for the performance verification of the proposed technique. Also AC feeding system is modeled through power analysis program and performance was verified through simulation according to various load changes. We verified that average 2.38%(distance equivalent 23.8 m) error appeared between the proposed estimation equation of catenary impedance and power analysis program simulation output in no connection double track system between up track and down track. Furthermore, We confirmed that estimation error is bigger depending on the increasing the distance from substation and vehicle impedance using only using vehicle current when calculating vehicle impedance in connection double track system between up track and down track. But, We confirmed that the proposed technique estimated accurately catenary impedance regardless of vehicle impedance and distance from substation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.236-241
• /
• 2004

In this paper, the dual stage interaction between the coarse actuator and the fine actuator of an optical disk drive and the control method to enhance the track pull-in performance are discussed. First, the interaction analyses for the dual stage, and the experiments to find the each actuator dynamics are studied. From the experiments results, some physical parameters was derived, then, some simulations are performed to find the residual vibration effect of the fine actuator during seek motion. Second, the fine actuator control method to reduce the relative velocity, which is a key factor in track pull-in performance, between the target track and beam spot is proposed. From simulations, we show that fine actuator control which has same frequency and same phase of the disturbance is effective to reduce the relative velocity, hence, the control method is good approach in the track pull-in enhancement. Finally, the some comments are discussed briefly.

• Journal of the Korean Society for Railway
• /
• v.10 no.5
• /
• pp.463-472
• /
• 2007

In this paper, the correlation between the vibration characteristics of the track components and the parameters affecting the vibration is analysed. To do it, the accelerations of each track component such as rails, sleepers and ballast are measured in Kyong-Bu high-speed line. The RMS values of the measured data are calculated and the pad stiffness, the longitudinal irregularity, running velocity and the corrugation, are considered as the parameters in the viewpoint of track. By using the linear regression, the correlation coefficient is calculated to analyse the relationship. Also, the 1/3 Octave analysis is calculated to analyse the dominant frequency band of tile vibrations of the track components.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1078-1083
• /
• 2008

In this paper, assessed are the stability of vehicle and track according to vertical support stiffness difference on the transition between conventional and zero-longitudinal resistance (ZLR) rail fastener on bridge. For this, the spring constants of rail fastener have been determined according to different load ranges - KTX load (with or without impact factor) and test load of EN standards - from results of laboratory test on rail pad, the stability analysis of vehicle and track has been performed according to numbers or installation length of ZLR fasteners using vertical vehicle-track coupled model to consider train-track interaction. The analysis results reveal that only the wheel load variation slightly exceed the limit value when 2 ZLR fasteners are used with spring constant determined within the EN test load range, but, in all other cases, all evaluation items are satisfied. Thus, it can be said that the stability of vehicle and track will not be degraded by ZLR fastener.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.4
• /
• pp.584-590
• /
• 2013

Depending on the operating characteristics, track circuit is installed for the purpose of control directly or indirectly of the signal device, point switch machine and other security device. These are mainly used for train detection, transmission of information, broken train detection and transmission of return current. Especially, the return current is related to signal system, power system and catenary line, and track circuit systems. It is one of the most important component shall be dealt for the safety of track side staff and for the protection of railway-related electrical system according to electrification. Therefore, an accurate analysis of the return current is needed to prevent the return current unbalance and the system induced disorder and failure due to an over current condition. Also, if the malfunction occurred by the return current harmonics, it can cause problems including train operation interruption. In this paper, we presented measurement and analysis method at return current and it's harmonics by train operation. By the test criteria, we evaluated for safety. Hereafter, it is expected to contribute to the field associated with it.