Impacts of wind shielding effects of bridge tower on railway vehicle running performance

Wu, Mengxue,Li, Yongle,Zhang, Wei Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.25 No.1

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.

곡선부 통과 차량의 동적거동 예측을 위한 주행안정성 해석

오정헌(Jeong-Heon Oh),엄범규(Beom-Gyu Eom),강부병(Bu-Byoung Kang),이희성(Hi Sung Lee) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

The two major factors related to the train driving safety are classified as the railway vehicle conditions and the track conditions In case of railway vehicles, there are static wheel load ratio, spring stiffness of primary and secondary suspension, effective center heights of railway vehicle, etc..and In case of tracks. there are curve radius, cant, rail irregularity, rail inclination, etc..These can influence in running stability of railway vehicle. Besides, the running speed and friction coefficient of wheel&rail are factors that influence in running stability of railway vehicle. In this study, when the railway vehicle passing through curves, the effect that has influence on running safety is examined to devise the high speed of vehicle which passing through curves which risk of derailment is high. it wished to reappear derailment mode using commercial analysis program. It achieved parts(wheelset, bogie, cars) modelling and running stability/derailment safety analysis using multibody dynamics program(ADAMS/View). Also, the dynamic behaviors of railway vehicle passing through curve are estimated by utilizing analysis results.

제동시의 철도차량을 위한 동적모델

박준혁,구병춘 한국철도학회 2007 한국철도학회논문집 Vol.10 No.4

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.

철도차량 제동 HILS 시스템의 개선된 윤축속력 구현

이동찬,강철구,Lee, Dong-chan,Kang, Chul-Goo 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.9

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.

철도차량 제동 HILS 시스템의 개선된 윤축속력 구현

이동찬(Dong-chan Lee),강철구(Chul-Goo Kang) 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.4

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.

도시철도차량 운영환경을 적용한 리튬배터리 SoC 고찰

오효석,김재영,최용은,문병민,김재문 대한전기학회 2023 전기학회논문지 Vol.72 No.5

Batteries for railway vehicles serve as the fundamental power source to maintain system operations, control power, and emergency power. In this paper, we investigate the operating environment and load usage conditions of lithium batteries applied in a 10-car formation of urban railway vehicles in Korea. We measure the initial capacity and SoC-OCV through charge-discharge experiments and select the partial discharge range based on the operating characteristics of urban railway vehicles. During operation, the load characteristics of railway vehicle batteries supply the load through the charging device, except for a certain section, and the battery discharge time is very short compared to the operating time. The charge and discharge experiments, considering the railway vehicle operating environment, show that the initial voltage of the discharge rapidly decreases, followed by linear discharge, and the charge gradually increases depending on the CV charging method of the railway vehicle. In the future, if we utilize the data acquired through the system established in this paper and the data from urban railway vehicles in operation, it is expected to estimate the State of Health(SoH) of lithium batteries installed in urban railway vehicles and be useful for maintenance.

Study of the active radial steering of a railway vehicle using the curvature measuring method

심경석,허현무,송현석,박태원 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.11

This study assesses the capability of an active steering bogie to run effectively on a curved track. It presents a curvature measuringmethod that can be implemented in a railway vehicle system to steer a railway vehicle. This method was used to conduct a field test. Theangle of attack and lateral force were reduced in a railway vehicle model on a curved track and analyzed. An active steering system wasimplemented to improve certain states when a railway vehicle runs on this track, such as wear and derailment index. The railway vehiclewas also equipped with an active steering bogie to limit lateral contact forces and wear rates between the wheel and the rail. Finally, thispaper describes the modeling of this active steering system and of a system to control the performance of a vehicle as it curves. Simulationresults with this bogie were better than those obtained with a conventional railway vehicle, including in terms of lateral forces andthe wear number of the wheels. Therefore, the proposed model is more effective than conventional systems with respect to operation on acurved track.

Analysis of high-speed vehicle-bridge interactions by a simplified 3-D model

Song, Myung-Kwan,Choi, Chang-Koon Techno-Press 2002 Structural Engineering and Mechanics, An Int'l Jou Vol.13 No.5

In this study, the analysis of high-speed vehicle-bridge interactions by a simplified 3-dimensional finite element model is performed. Since railroads are constructed mostly as double tracks, there exists eccentricity between the vehicle axle and the neutral axis of cross section of a railway bridge. Therefore, for the more efficient and accurate vehicle-bridge interaction analysis, the analysis model should include the eccentricity of axle loads and the effect of torsional forces acting on the bridge. The investigation into the influences of eccentricity of the vehicle axle loads and vehicle speed on vehicle-bridge interactions are carried out for two cases. In the first case, only one train moves on its track and in the other case, two trains move respectively on their tracks in the opposite direction. From the analysis results of an existing bridge, the efficiency and capability of the simplified 3-dimensional model for practical application can be also verified.

철도차량 롤 특성에 대한 고찰

김필환(Kim Pil-Hwan) 한국철도학회 1998 한국철도학회 학술발표대회논문집 Vol.- No.-

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 of carbody to that of rail-cant. The limit values of roll coefficient recommended in UIC are 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 also performed. The results show that roll-characteristics affect the roll-over of vehicle.

능동조향대차 곡선검지 센서의 곡률 추출 성능시험

허현무(Hyunmoo Hur),이준혁(Junhyuk Lee),서정원(Jungwon Seo),문경호(Kyungho Moon),최종현(Jonghyun Choi) 한국철도학회 2024 한국철도학회논문집 Vol.27 No.3

곡선구간 주행 성능 향상을 위하여 개발한 능동조향대차에 장착된 곡선검지 센서 시제의 곡률 추출 성능을 검증하고자 실선로에서의 현차적용 시험을 수행하였다. 차량 구동형식이 곡률 추출 성능에 미치는 영향을 분석하고자 부수대차 차량과 구동대차 차량을 대상으로 곡률을 측정한 결과, 궤도검측 결과와 비교할 때, 최대 편차는 공차 시 부수차량, 구동차량 모두 3.4%이며 만차 시 부수차량은 1.8%, 구동차량은 2.2% 수준으로 차량 구동형식에 따른 뚜렷한 차이점은 발견되지 않았다. 차량 하중조건이 곡률 추출 성능에 미치는 영향은, 부수대차 차량의 경우, 궤도검측 결과와 편차는 공차 3.4%, 만차 1.8%이며 구동대차 차량의 경우, 공차 3.4%, 만차 2.2%로 매우 미미한 수준이다. 따라서 능동조향대차 곡선검지 센서의 곡률 추출 성능은 차량 구동형식이나 하중조건에는 거의 영향을 받지 않는 매우 안정된 곡률추출 성능을 보이고 있다고 평가된다. 따라서 본 곡선검지 센서는 곡선구간 차량 제어를 위한 곡선 검지기술 분야에서 매우 실용적인 기술로 활용될 것으로 기대된다. To verify the curvature estimation performance of a curve detecting sensor prototype mounted on an active steering bogie developed to improve the running performance of a railway vehicle on a curved section, a test run was conducted on the test line. To analyze the effect of the driving type of the bogie on the curvature estimation performance, the curvature was measured for a trailer bogie vehicle and a driving bogie vehicle. Compared to the track curvature inspection results, the maximum deviation was 3.4% at tare-load condition and 1.8% at full-load condition for the trailer bogie vehicle. For driving bogie vehicle, the maximum deviation was 3.4% at tare-load condition and 2.2% at full-load condition; thus, no significant difference was found according to the bogie driving type. The effect of vehicle load conditions on curvature estimation performance was also very insignificant. For the trailer bogie vehicle, the deviation from the track curvature inspection result was 3.4% at tare-load condition and 1.8% at full-load condition. And, in the case of driving bogie vehicles, the deviation was 3.4% at tare-load condition and 2.2% at full-load condition. Therefore, the curvature estimation performance of the curve detection sensor of the active steering vehicle is evaluated as excellent hardly affected by vehicle driving types or load conditions. Therefore, this curve detecting sensor is expected to be used as a practical technology in the field of curve detection technology for vehicle control in curved sections.