• Wind and Structures
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• v.20 no.2
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• pp.143-168
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• 2015

A numerical model for analyzing air-train-track interaction is proposed to investigate the dynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of a train-track interaction model and a train-air interaction model. The train-track interaction model is built on the basis of the vehicle-track coupled dynamics theory. The train-air interaction model is developed based on the train aerodynamics, in which the Arbitrary Lagrangian-Eulerian (ALE) method is employed to deal with the dynamic boundary between the train and the air. Based on the air-train-track model, characteristics of flow structure around a high-speed train are described and the dynamic behavior of the high-speed train running on track in crosswinds is investigated. Results show that the dynamic indices of the head car are larger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the running safety of the train in crosswinds is basically controlled by the head car. Compared with the generally used assessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio, the overturning coefficient will overestimate the running safety of a train on a track under crosswind condition. It is suggested to use the wheel-load reduction ratio and the lateral wheel-rail force as the dominant safety assessment indices when high-speed trains run in crosswinds.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1536-1541
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• 2011

Simple girder bridges are more economical than commonly used PSC box girder bridges in high-speed railway construction, if they secure the riding stability. In this study, the dynamic behavior and riding stability of the newly developed precast V-girder bridge are analyzed. The dynamic moving load analysis is used including two train load case : the KTX train and freight train.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.116-122
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• 2000

This paper presents a simulation method with constant power model for the train load. In power system simulation loads could be modeled as a constant power, constant current, constant Impedance or a function of voltage and frequency. At this time, however, representing a train load as the function is difficult because of the lack of data. Therefore as a first step, simulation method with a constant power model fer a train is studied, and the test result is compared with the simulation result using the constant Impedance model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1023-1024
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• 2011

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.529-544
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• 2007

After rapid running is begun in domestic, problem by the train gust that was not considered at existent train running appeared. If the High-Speed railway business speed rises by 350km/h in the future, is going to become more big problem. This study conducts an experiment that measure in local about KTX train beside Gyeong-Bu High speed railroad track about aerodynamics effect that happen by passage of train and analyzed. In case KTX II runs with the 350km/h speed, forecasted effect that get in the simple vertical surfaces parallel to tracks according to distance from rail center. Compared construction size with structural analysis in case do not consider with case that consider the train gust about sound proof walls representatively. As a result, proposed wind load standard that apply at sound proof walls design.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.529-538
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• 2009

A trial run of locally-developed tilting train has been in process on Chungbuk line since the test vehicle was first produced. For the system stabilization, interface verification among the systems including track, structure, catenary and signaling system, not to mention the rolling stock, is very crucial. Therefore, in this study, the dynamic rail force of the tilting (Hanvit 200), high-speed (KTX) and general (Mugunghwa) vehicle caused by driving in transition curve track was measured. And, it compared the tilting response with the other by using the measured wheel load data in transition curve track, and then evaluated probability the range of wheel load fluctuation for the variable dynamic vertical and lateral wheel load. As a result, a range of wheel load by occured a change of cant from the high-speed and general vehicle which had fixed bogie structure was distributed throughout small deviation (${\Delta}8{\sim}13kN$). Otherwise, in case of the tilting train which was consisted of the pendulum bogie structure was distributed wide range about large deviation (${\Delta}25{\sim}28kN$) by changed of cant.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1514-1518
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• 2009

Recently, railroad construction has been increased all over the world and as the train is getting high-speeded, there has been a need for guaranteed safety, so that a requirement for heath monitoring techniques for destruction that generated by gradually accumulated damages is now increasing. Especially the rail is crucial part that contact with wheel directly and delivers the train's load to a sleeper. It needs a technique that can guarantee a safety by sensing the possible cracks. In this paper, when train's load applied to the rail, strain distribution that introduced to entire length of rail is monitored using optical fibre. Optical fibre is used as a medium for measuring the strain and BOCDA (Brillouin Optical Correlation Domain Analysis) system is organized for measuring the distributed variation that implied to optical fibre. Optical fibre is attached at lower flange where tension is maximized when the load of train applied to the rail and strain gauge is implied together to compare the accuracy of measurement.

• International Journal of Safety
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• v.5 no.1
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• pp.1-4
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• 2006

The safety performance of the current collection system is evaluated by conducting a test run in which accelerometer and load cell signals are analyzed. It has been found that the current collection performance is strongly influenced by the train speed, with the major frequency components arising from the train traversing the span spacing and the 8.5 Hz component originating from the panhead resonance. The train acceleration is found to have significant influence on the span passing frequency but negligible effect on the resonant response.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.467-475
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• 2012

Static and dynamic train load tests were conducted to evaluate the train load transfer mechanism in the roadbed which was retained by two types (fully and partially) of segmental retaining walls reinforced by geogrid. The test roadbed was 2.6m high, 5m wide, and 6m long. A combination of earth pressure gages, displacement transducers, and strain gages were placed in specific locations to measure the responses. Test results showed that the wall displacement pattern as well as the earth pressure for the fully reinforced retaining wall was different from those for the partially reinforced retaining wall. In the dynamic train load test, the strain in the upper part of the wall tended to decrease, and both the residual deformation and the rate of the deformation were significantly lower than those in the current design standard.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.411-416
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• 2002

The strength evaluation of a wheel is becoming very important due to the high speed of railway system and the reduction of wheel weight. Therefore, in this study, the influence of thermal stress at tread breaking in Korean High Speed Train wheel was investigated using FEM. During FEM analysis, the mechanical load or wheel-rail contract load and braking load were considered. When 300% of the block force was applied, the maximum von Mises stress of 61.0 ㎫ was found at the outside plate around 400mm far away from the wheel center.