• Proceedings of the KSR Conference
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• 2000.11a
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• pp.282-291
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• 2000

In this paper, the dynamics of automated guideway transit vehicles with rubber tires are studied. Two different AGT models are considered: the bogie system and the steering system . It is found that the bogie system is stable at all possible operating speeds, whereas it is not true fur the steering system. To investigate the dynamic stability of steering systems, the critical speeds are investigated and the dynamics of the closed-loop steering control system are numerically simulated.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.125-134
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• 2000

This paper presents the results of vehicle dynamics simulation for development of single axle bogie for freight vehicle. Those results consists of hunting stability, ride comfort and curving performance such as derailment ratio, unloading ratio. Dynamic behaviors of vehicle having single axle bogie is carried out using the multi-body dynamics simulation program(VAMPIRE). The results of analysis meet the criteria proposed by Korean National Railroad(KNR) and Korea Railroad Research Institute(KRRI).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1371-1377
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• 2013

In this analysis, a method is presented to calculate the critical speed of a railway vehicle by using a multibody dynamic model. The contact conditions and contact forces between the wheel and the rail are formularized for the wheelset model. This is combined with the bogie model to obtain a multibody dynamic model of a railway vehicle with constraint conditions. First-order linear dynamic equations with independent coordinates are derived from the constraint equations and dynamic equations of railway vehicles using the QR decomposition method. Critical speeds are calculated for the wheelset and bogie dynamic models through an eigenvalue analysis. The influences of the design parameters on the critical speed are presented.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.116-120
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• 2010

The wheelset, an assembly of wheel and axle, is one of important parts in railway bogie, directly related with the running safety of railway rolling stock. In this investigation, the tensile failure behavior of railway axle materials was investigated. The tensile coupons were prepared from the actual rolling stock parts, which were operated over 20 years. The tensile testing was performed according to the KS guideline. During tensile testing, an infrared camera was employed to monitor temperature changes in specimen as well as demonstrate temperature contour in terms of infrared thermographic images. The thermographic images of tensile specimens showed comparable results with mechanical behavior of tensile materials. In this paper, the failure mode and behavior of railway axle materials were provided with the aid of infrared thermography technique.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.547-555
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• 2016

The wheel wear of a railway vehicle is mainly generated when maneuvering on a curved track. The change in the wheel profile affects the dynamic stability of the vehicle. In this analysis, the wheel wear volume was calculated while changing the velocity and radius of the curve to analyze the wear characteristics of a wheel at a curved section. The wear index was calculated from a vehicle dynamic analysis based on a multibody dynamics analysis and wear volume from a wear model by British Rail Research. The wear volume at a radius of 300 m is dominant compared with other radii. The wear volume was calculated by assigning different coefficients of friction to the tread and flange of the wheel to investigate the effect of lubrication on the wear characteristics. The effect of the improvement by lubrication is calculated by varying the radius of the track, and is assessed on an actual urban railway section.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.199-211
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• 2018

Ever since Korea was geopolitically divided into North and South Korea in the 1940s, South Korea has depended on maritime transportation for global trade and logistics. Now, however, South Korea is preparing to develop a new global route for trans-Eurasia logistics passing through North Korea. Even though there are difficulties to overcome, South Korea expects that a new overland route, shorter than the existing seaways in the Europe-Asia section, will bring more frequent trade with more rapid and cost-effective logistics services in the future. Related to this issue, this study aims to proactively analyze dynamic logistics changes in South Korea when a trans-Korea railway is developed and linked with the trans-China railway and the trans-Siberian railway. This study employed a system dynamics simulation approach to model the logistics system in South Korea. The simulation results indicated that the traffic of the Uiwang inland container depot near the capital area may increase but the traffic of the Port of Busan may decrease. With supplementary research, consequently, follow-up studies on adjusting the traffic capacity in Korea are required to attain successful trans-Eurasia logistics by rail.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.147-153
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• 2012

Precise estimation f a structure's dynamic characteristics is indispensable for ensuring stable dynamic response during life time especially for the structures which can experience resonance such as railway bridges. Especially, concrete track can change the modal properties of the railway bridge, through the contribution of stiffness as well as mass effects, generally only the mass effect is considered in dynamic analysis of the railway bridge. In this paper, static and dynamic behaviors of railway bridge with concrete track were investigated through experimental study. Also, numerical analysis was performed about considering only mass of concrete track and together with stiffness and mass of concrete track. These were compared with experiment value. Numerical analysis value considering together with stiffness and mass of concrete track was similar experiment value. Therefore, when dynamic analysis of railway bridge with concrete track is performed, the contribution of stiffness as well as mass effects for concrete track is considered.

• Wind and Structures
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• v.21 no.1
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• pp.105-117
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• 2015

This paper presents a numerical characterization of real railway overhead cables based on computational fluid dynamics (CFD). Complete analysis of the aerodynamic coefficients of this type of cross section yields a more accurate modelling of pressure loads acting on moving cables than provided by current approaches used in design. Thus, the characterization of certain selected commercial cables is carried out in this work for different wind speeds and angles of attack. The aerodynamic lift and drag coefficients are herein determined for two different types of grooved cables, which establish a relevant data set for the railway industry. Finally, the influence of this characterization on the fluid-structure interaction (FSI) is proved, the static behavior of a catenary system is studied by means of the finite element method (FEM) in order to analyze the effect of different wind angles of attack on the stiffness distribution.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.201-207
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• 2003

Sensitivity analysis of suspension elements of an articulated bogie for light railway vehicles is presented. The ride, stability and safety are used as dynamic performance indices. Suspension elements of 10 and a conicity of wheel are used as design variables. To analyze sensitivity of design variables. the railway vehicle dynamics analysis program AGEM is used. The results show that the secondary suspension elements have a strong effect on ride and the primary suspension elements have a moderate effect on ride. Conicity of wheel has a strong effect on the stability. The safety is not effected by all the design variables.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.2
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• pp.162-167
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• 2017

The chevron rubber spring is used for subway vehicle as a primary suspension. Generally, the primary suspension has an influence to the running performance and not so much effect on the ride comfort in railway vehicle. But the stiffness of chevron spring is harder and harder as time goes on because of rubber characteristics. Therefore the dynamic characteristics such as ride comfort and derailment coefficient should be reviewed according to the stiffness variation of chevron rubber spring. In this paper the effect of chevron rubber spring on dynamic characteristics was studied by considering multi-body dynamics of railway vehicle on one straight line and seven curved lines.