• 한국기계연구소 소보
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• s.15
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• pp.5-17
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• 1985

Dynamics of railway vehicles are strongly influenced by the wheel/rail contact forces. Wheel/rail contact geometric characteristics are important parameters to determining wheel/rail contact forces. In general, geometric relations between wheel and rail are represented by nonlinear functions of the wheelset lateral excursion and the relative yaw angle. There are some analytical and experimental studies to show the influences of the wheelset lateral displacement on wheel/rail geometric relations. Recently radial steering bogie which is designed to have flexible yaw motions of wheelsets was developed to improve curve negotiation performance. The radial steering bogie makes it important problem to study the effects of wheelset yaw motion on wheel/rail geometric relations. This paper describes the method to analyze 3-dimensional wheel/rail contact geometry considering wheelset yaw motion and describes also some computer simulation results.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.606-610
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• 2004

In this paper, we would like to explain about the structure analysis of wheel set as variation of contact position between wheel and rail. Measurement of interacted force between wheel and rail is necessary for running safety evaluation as important factor of derailment mechanism. It's necessary to running safety evaluation of rolling stock. Wheel unload and lateral force change as variation of contact position between wheel and rail. Interacted force between wheel and rail got as each contact position through computer simulation. This is necessary process as first research for evaluation of derailment phenomenon and running safety.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.9
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• pp.783-790
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• 2014

Railway wheels and axles are the most critical parts of the railway rolling stock. The wheel carry axle loads and guide the vehicles on the track. Therefore, the contact surface of wheel are subjected to wear and fatigue process. The wheel damage can be divided into three types; wear, contact fatigue failure and thermal crack due to braking. Therefore, in the contact surface between the wheel and the rail, the materials are heat treated to have a specific hardness. The manufacturing quality of the wheel have a considerable influence on the formation of tread wear and damage. Also, the residual stress on wheel is formed during the manufacturing process is one of the main sources of the damage. In this paper, the mechanical characteristic and the residual stress according to wheel material have been evaluated by applying finite element analysis and conducting mechanical tests.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.1-14
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• 2013

In this paper, a finite element analysis technique of rolling stock models for collision-induced derailments was suggested using rolling contacts for wheel-rail interaction. The collision-induced derailments of rolling stock can be categorized into two patterns of wheel-climb and wheel-lift according to the friction direction between wheel flange and rail. The wheel-climb derailment types are classified as Climb-up, Climb/roll-over and Roll-over-C types, and the wheel-lift derailment types as Slip-up, Slip/roll-over and Roll-over-L types. To verify the rolling contact simulations for wheel-rail interaction, dynamic simulations of a single wheelset using Recurdyn of Functionbay and Ls-Dyna of LSTC were performed and compared for the 6-typical derailments. The collision-induced derailment simulation of the finite element model of KHST (Korean High Speed Train) was conducted and verified using the theoretical predictions of a simplified wheel-set model proposed for each derailment type.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1225-1231
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• 2009

One reaction wheel cluster of satellite usually has four reaction wheels. Each wheel is not arranged parallel to the attitude axis of satellite. Therefore, if one reaction wheel is broken, it is very hard to isolate the fault except using the sensors of wheel itself. In this paper, the isolator of satellite reaction wheel cluster is designed. Using a dual filter, FDP(Fault Detection Parameter) is made to detect fault, and using a multi-hypothesis extended Kalman filter, fault isolation of wheel cluster is done. We verify the improvement of isolation performance of wheel cluster by simulation with 4-reaction wheel cluster.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.857-861
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• 1997

In discontinuous wheel grinding, temperature is different form conventional grinding. The characteristics of discontinuous grinding with respect to various slotted wheel were compared with those of general grinding. Thermal conditions vary with intermittent ratio, direction of fluid supply for discontinous wheel. According to three direction of grinding fluid supply and intermittent ratio,temperature and surface roughness were analyzed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.185-188
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• 2002

An abrasive vitreous bonded solid mass having a vitrified abrasive structure comprising diamond grains which are held by an in inorganic bonding agent, the vitrified diamond wheel is impregnated with a composition which comprises a thermosetting synthetic resin and a surfactant. The vitrified diamond wheel is manufactured by preparing the composition including the resin and the surfactant, impregnating the abrasive structure with the composition, and curing the composition. The diamond wheel newly developed showed excellent performance in grinding carbide.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.1
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• pp.205-215
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• 2001

In this study, modeling and analysis procedure for the dynamic analysis of a high mobility tracked vehicle system were studied. The vehicle model used in this investigation is assumed to be consist of two kinematically decoupled subsystems. The chassis subsystem consists of chassis frame, sprocket, support rollers, road wheels, idler wheel, road wheel arms and idle wheel arm, while the track subsystem is represented as a closed kinematic chain consisting of track links and end connectors interconnected by revolute joints with bushing. Nonlinear contact force module describing the interaction between track link, and sprocket, idler wheel, road wheel, support roller, ground was used. The effects of road wheel arms and idler wheel arm due to tension adjuster are also considered.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1011-1016
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• 2010

The noise emitted during train operation is generated with various reasons. It is known that the major noise generation is classified according to the ranges of train speed; that is, engine noise at lower speed range, rolling noise at medium speed range, and air-borne noise at higher speed range. These noises are transmitted in combined form with the noises generated from track components and under-carriage, etc. The rolling noise as a major noise at medium speed range is caused by the vibration occurred at wheel/rail interface. The vibration occurred at wheel/rail interface is transmitted to wheel and rail, and this vibration is emitted from wheel and rail as a noise. The object of this study is to investigate the effect of wheel damper of low noise wheel. In this study theoretical and experimental analysis is performed by numerical model calculations and impact test.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.879-883
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• 2000

A system for measuring and adjusting the oscillating frequency of a balance wheel whick determins the accuracy of mechanical timers. The balance wheel oscillates rotatively suspended by a hair spring which is welded at the other end to the pivot tube. The natural oscillatory frequency of the balance wheel is determined by the length of hairspring from the balance wheel to the point if other parameters the length in the torsional oscillation model are not changed, so the frequency of the balance wheel can be adjusted to meet a requirement by the adjustment of the hairspring length using ultrasonic welding. And the movement of wheel teeth is measured in realtime by a high speed photo fiber sensor and Auto Correlation is used to find a more accurate oscillation period from the measured signal with some variations.