• 한국철도학회논문집
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• 제10권4호
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• pp.431-437
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• 2007

This paper describes the dynamic modeling of a railway vehicle when it is under braking force. It is important for the enhancement of braking performance to establish a proper dynamic model of a railway vehicle because the braking performance is affected by some dynamic forces generated by a railway vehicle when it undergoes braking. In this paper, a dynamic model for one vehicle is suggested to compute the dynamic behavior of a railway vehicle in the HILS(Hardware In-the-loop Simulation) system for the railway vehicle braking devices. To simplify the dynamic model, friction between a wheel and a rail is assumed that there exist only the static and the dynamic friction forces. Static friction coefficient is also assumed to be a function of the running speed. Some simulations are carried out with various braking forces, and the braking characteristics according to the change of the braking force are discussed. This study can provide some fundamental results to construct the HILS system for braking devices of a railway vehicle.

• Wind and Structures
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• 제25권1호
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• pp.63-77
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• 2017

When railway vehicles run by towers of long span bridges, the railway vehicles might experience a sudden load-off and load-on phenomenon in crosswind conditions. To ensure the running safety of the railway vehicles and the running comfort of the passengers, some studies were carried out to investigate the impacts of sudden changes of aerodynamic loads on moving railway vehicles. In the present study, the aerodynamic coefficients which were measured in wind tunnel tests using a moving train model are converted into the aerodynamic coefficients in the actual scale. The three-component aerodynamic loads are calculated based on the aerodynamic coefficients with consideration of the vehicle movement. A three-dimensional railway vehicle model is set up using the multibody dynamic theory, and the aerodynamic loads are treated as the inputs of excitation varied with time for kinetic simulations of the railway vehicle. Thus the dynamic responses of the railway vehicle passing by the bridge tower can be obtained from the kinetic simulations in the time domain. The effects of the mean wind speeds and the rail track positions on the running performance of the railway vehicle are discussed. The three-component aerodynamic loads on the railway vehicle are found to experience significant sudden changes when the vehicle passes by the bridge tower. Correspondingly, such sudden changes of aerodynamic loads have a large impact on the dynamic performance of the running railway vehicle. The dynamic responses of the railway vehicle have great fluctuations and significant sudden changes, which is adverse to the running safety and comfort of the railway vehicle passing by the bridge tower in crosswind conditions.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.122-130
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• 2013

Rail geometries such as cant, grade and curvature can be easily represented by means of a track coordinate system. In this analysis, in order to derive a dynamic and constraint equation of a wheelset, the track coordinate system is used as an intermediate stage. Dynamic and constraint equations of railway vehicle bodies except the wheelset are written in the Cartesian coordinate system as a conventional method. Therefore, whole dynamic equations of a railway vehicle are derived by combining wheelset dynamic equations and dynamic equations of railway vehicle bodies. Constraint equations and constraint Jacobians are newly derived for the track coordinate system. A process for numerical analysis is suggested for the derived dynamic and constraint equations of a railway vehicle. The proposed dynamic analysis of a railway vehicle is validated by comparison against results obtained from VI-RAIL analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.528-535
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• 2011

According to railway safety regulations for securing the railway vehicle's quality and performance, it can be partly exempted that the performance tests and production inspections on the railway vehicles which are produced and assembled for the purpose of test and research. The reasons of this exemption are for ensuring maximum autonomy and for saving time considered the development period of railway vehicle. However, it was continuously demanded the necessity of supplementation on the confirmation about railway vehicle's quality & performance. Therefore, we added "The monitoring step" which is for securing the quality and performance in high speed railway vehicle's subsystem & compartment to supplement those tests & inspections in development. In this paper, based on a standard ABS(Activity Breakdown Structure) of railway vehicle and a WBS(Work Breakdown Structure) of the railway vehicle system, we investigate the necessity of monitoring in the High speed railway vehicle development. And by comparing and analyzing the essential requirements of international standard, IRIS(International Railway Industry Standard) & TSI(Technical Specification for Interoperability), we try to examine a standard monitoring procedure.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2691-2696
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• 2011

THE CARBODY AND BOGIE FRAME OF AN URBAN RAILWAY VEHICLE CONSIST OF MULTI-LAYERED WELDING STRUCTURE. IN KOREA ENDURANCE LIMIT OF AN URBAN RAILWAY VEHICLE IS STSTED IN THE RULE OF MANAGING URBAN RAILWAY VEHICLE UNDER THE LAW OF URBAN RAILWAY. IN KOREA AN URBAN RAILWAY VEHICLE IS DESIGNED AND MADE TO KEEP ITS QUALITY OVER 25 YEARS. WHEN THE RAILWAY VEHICLE BECOMES 25 YEARS OLD, CORROSION OF CARBODY AND UNDER FRAME OF A RAILWAY VEHICLE IS EVALUATED ACCORDING TO THE NON-DESTRUCTIVE TESTING. IT CAN BE USED AS LONG AS 40 YEARS. IT IS STATED IN THE ARTICLE 4 'THE METHOD AND STANDARDS OF PRECISE DIAGNOSIS' UNDER THE RULE OF MANAGING RAILWAY VEHICLE IN KOREA. SO, IN THIS STUDY, WE HAVE INVESTIGATED PERFORMANCE OF PULSED EDDY CURRENT TESTING METHOD BY MEASURING THICKNESS VARIATION OF FABRICATE OF CARBODY AND UNDER FRAME FOR URBAN RAILROAD CAR. AND THEM, THE PROCESS OF EVALUATING REMAINING LIFE ACCORDING TO TESTING OF CORROSION AMOUNT IS INTRODUCED.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1862-1867
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• 2011

Recently, a railway vehicle of the maximum speed of 350km/h or more high speed has been developed in the developed country. The next-generation railway vehicle(HEMU-400X) is being developed for aim to run over 430km/h in Republic of Korea, too. The safety of the railway vehicle should be conformed before manufacturing the railway vehicle. In this study, the next generation high-speed railway vehicle was modeled as a single-car system using commercial dynamic program ADAMS/Rail. Safety analysis was implemented through the international standard of the UIC 518 OR code. Also, appropriateness of the railway vehicle design variable were conformed by safety analysis results.

• 제어로봇시스템학회논문지
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• 제21권9호
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• pp.881-887
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• 2015

The hardware-in-the-loop simulation (HILS) of a railway vehicle is crucial for overcoming the limitation of field tests of a railway vehicle. A brake HILS system for a railway vehicle was previously not able to test the performance of a speed-sensing system of a railway vehicle, since wheelset speeds were generated only by computer simulations. In this paper, we present a novel wheelset speed implementation of a brake HILS system for a railway vehicle. Four wheelset speeds of a brake HILS system for a car of a railway vehicle are implemented using four small-sized servomotors, whereas the speed sensors and pole wheels used in the brake HILS system are the actual ones of the railway vehicle. According to the simulated speeds of four wheelsets in the dynamic equations of motion, four servomotors generate wheel speeds in real time, and then the measured wheelset speeds are fed back to the computer simulation model. Moreover, in this paper, we improve the performance of wheelset speed measurement via the T method instead of the M method presently used in the field. The performances of wheelset speed implementation and speed-sensor operation are demonstrated by experimental works using a HILS system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.512-521
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• 1998

The roll characteristic of railway vehicle is an important factor that affects the roll-over of vehicle and lateral ride comfort of passenger. Generally the roll characteristics of railway vehicle is defined by the term of roll-coefficient, s, which represents the ratio of incline or carbody to that of rail-cant. The limit values of roll coefficient recommended in UIC Bre 0.4 for coach without pantograph and 0.15 for vehicle with pantograph. The roll coefficient can be calculated by VAMPIRE that is the well-known commercial software for analysis of dynamic behavior of railway vehicle. The value of roll coefficient is effected by height of gravity center of carbody, stiffness of primary and secondary suspension and etc. The calculated roll-coefficient for electric locomotive and passenger coach is 0.12 and 0.77 respectively, The additional equipment such as anti-roll bar is considered in order to decrease roll-coefficient of passenger coach. In relation to roll characteristics, the analysis for roll-over due to wind is a1so performed. The results show that roll-characteristics affect the roll-over of vehicle.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.248-253
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• 2013

The maximum speed is one of the most important performance in high speed railway vehicle. The higher the train speed is, the worse the ride comfort is, In order to solve this problem, a semi-active or active suspension can be applied to high speed railway vehicle. The variable damper with hydraulic solenoid valve is used in the semi-active suspension. But the variable damper with hydraulic solenoid valve requires tank for supplying fluid. The MR(Magneto Rheological) damper can be considered instead of hydraulic variable damper which needs additional device, i.e. reserver tank for fluid. In the case of active suspension, hydraulic actuator or electro-mechanical one is used to suppress the carbody vibration in railway vehicle. In this study the MR damper and electro-mechanical actuator was considered in secondary suspension system of high speed railway vehicle. The dynamic analysis was performed by using 10-DOF dynamic equations of railway vehicle. The performance of the semi-active suspension and active suspension system were reviewed by using MATLAB/Simulink S/W. The vibration suppression effect of semi-active and active suspension system were investigated experimentally by using 1/5-scaled railway vehicle model.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.863-869
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• 2002

Studied in this paper was the kinematic envelope of the railway vehicle to calculate the lateral displacement using the multi-body dynamic simulation program (VAMPIRE) and the BASS 501. The lateral displacement of railway vehicle is occurred by the clearance between wheel flange and rail, the track irregularity, the property of each suspension of vehicle and the cant of track etc. The results of analysis shown that Vehicle is not interfere with subway platform in any conditions namely the tare and full load condition, the wheel wear condition and the stationary and running of vehicle.