• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.777-783
• /
• 2007

Life cycle costing is one of the most effective cost approaches when we choose a solution from series of alternative so the least long-term cost ownership is achieved. Life cycle costing in railway industry has been focused on the prediction of investment for railway vehicles. But in today, the life cycle cost, LCC, prediction on the aspect of operation and maintenance cost through whole life cycle is highly necessary. In this paper, we present a strategy for the development of life cycle cost estimation software on the aspect of maintenance strategies of railway vehicle. For this purpose, we suggested a structure of LCC software based on the UNIFE LCC model. And we developed a pilot version of software to evaluate the LCC model that we suggested for railway vehicle. We performed LCC analysis on the brake module of metro vehicle in case study and concluded that the software and model developed in this research could enough to support engineers in choosing better cost effective solutions from many alternatives.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.1195-1200
• /
• 2008

The railway bridge design specification used in our country at present, is reflected results that take into account link between vehicle and roadbed according to decision of TGV vehicle style in 1994, and executes design verification. Hereafter, the particular loading condition and the design speed of the high-speed EMU that is recognized to the next generation of high speed railway, are plain difference with TGV vehicle style decided in 1994. The effect that these load and design speed get in roadbed, especially superstructure, displays difference with the existent high speed railway. The goal of this study is to choose the suitable bridge type, and to reduce the construction cost for the next generation of railway, i.e., the high-speed EMU.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.219-222
• /
• 2009

Green ocean is one of the main issues internationally. Most governments are leading the role in boosting the economy through creating new green market and establishing system of coping with increasing international environmental regulation. Green ocean, which is a solution for the environmental issue of global warming, is applied throughout the industry. Domestic transportation industry including railway is also developing technology for creating green ocean. Transportation must decrease energy consumption at running stages because it shows high environmental loads expecially on using stages during its life cycle. Therefore, There are some tries for developing technologies; new engine through alternative energies, hybrid and lightweight. Railway transportation can not be exception. it is intended for this paper to suggest the direction of manufacturing environmentally friendly railway vehicle through the global warming effect evaluation of several materials being applied to vehicle and comparison of the results.

• 한국철도학회논문집
• /
• 제3권1호
• /
• pp.12-18
• /
• 2000

This paper addresses the experimental study on the nonlinear critical speed and the validity of simple prediction formulation. The experiment on nonlinear critical speed is carried out using roller rigs, which has been impossible on track because of a possibility of an accident. In addition, experiment for a bogie is performed to check the difference in modeling a full railway vehicle and a bogie. It is found that nonlinear critical speed proves to be an inherent phenomenon of a railway vehicle itself and the difference of test results between a full railway vehicle and a bogie is comparatively negligible. Finally. the accuracy of simple prediction formulation for outbreak velocity and response frequency in hunting is investigated.

• Structural Engineering and Mechanics
• /
• 제83권6호
• /
• pp.709-727
• /
• 2022

Fastening systems have a significant role in the response of railway slab track systems. Although experimental tests indicate nonlinear behavior of fastening systems, they have been simulated as a linear spring-dashpot element in the available literature. In this paper, the influence of the nonlinear behavior of fastening systems on the slab track response was investigated. In this regard, a nonlinear model of vehicle/slab track interaction, including two commonly used fastening systems (i.e., RFFS and RWFS), was developed. The time history of excitation frequency of the fastening system was derived using the short time Fourier transform. The model was validated, using the results of a comprehensive field test carried out in this study. The frequency response of the track was studied to evaluate the effect of excitation frequency on the railway track response. The results obtained from the model were compared with those of the conventional linear model of vehicle/slab track interaction. The effects of vehicle speed, axle load, pad stiffness, fastening preload on the difference between the outputs obtained from the linear and nonlinear models were investigated through a parametric study. It was shown that the difference between the results obtained from linear and nonlinear models is up to 38 and 18 percent for RWFS and RFFS, respectively. Based on the outcomes obtained, a nonlinear to linear correction factor as a function of vehicle speed, vehicle axle load, pad stiffness and preload was derived. It was shown that consideration of the correction factor compensates the errors caused by the assumption of linear behavior for the fastening systems in the currently used vehicle track interaction models.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.628-635
• /
• 2009

To assure the safety of urban railway train, it is necessary to observe the specified driving principles under an essential condition during running on tracks. These principles arises from a great deal of experience for a long time and include safe distance between trains, the railway signaling, block system, regular block of the highest priority and driving prohibition of simple railway vehicle in the main track, etc. Therefore, it is important to apply these principles to domestic urban railway driving regulations and railway vehicle driving regulations. However, domestic urban railway administrator established his own operation rules within the regulation. In this study, domestic urban railway administration's own rules are examined and the appropriate driving regulation on the safe driving principles is proposed.

• 한국철도학회논문집
• /
• 제2권2호
• /
• pp.6-12
• /
• 1999

In this study, the most important suspension characteristics of railway vehicle, such as primary and secondary stiffness, are optimized to maximize ride qualify. Critical speed, secondary suspension stroke oil tangent track and derailment coefficient on the maximum curvature, are selected as the performance constraints. Piecewise linear curving model is used to evaluate derailment coefficient where it is assumed that wheel/rail contacts occurs at tread or at idealized flange. The combined design procedure is used to optimize above design variables at the same time.

• Wind and Structures
• /
• 제20권2호
• /
• pp.237-247
• /
• 2015

Wind tunnel experiments are used to investigate the aerodynamic interactions between vehicles and wind barriers on a railway bridge. Wind barriers with four different heights (1.72 m, 2.05 m, 2.5 m and 2.95 m, full-scale) and three different porosities (0%, 30% and 40%) are studied to yield the aerodynamic coefficients of the vehicle and the wind barriers. The effects of the wind barriers on the aerodynamic coefficients of the vehicle are analyzed as well as the effects of the vehicle on the aerodynamic coefficients of the wind barriers. Finally, the relationship between the drag forces on the wind barriers and the aerodynamic coefficients of the vehicle are discussed. The results show that the wind barriers can significantly reduce the drag coefficients of the vehicle, but that porous wind barriers increase the lift forces on the vehicle. The windward vehicle will significantly reduce the drag coefficients of the porous wind barriers, but the windward and leeward vehicle will increase the drag coefficients of the solid wind barrier. The overturning moment coefficient is a linear function of the drag forces on the wind barriers if the full-scale height of the wind barriers $h{\leq}2.5m$ and the overturning moment coefficients $C_O{\geq}0$.

• 한국정밀공학회지
• /
• 제32권7호
• /
• pp.597-602
• /
• 2015

In this paper, we studied the steering performance of wheelset with primary suspension characteristics of railway vehicle. We carry out dynamic analysis and experimental study for the vehicle models which are different primary suspension characteristics. The steering angle of a vehicle model (Case 1) operating in domestic subway lines is insufficient compared with an objective steering angle for curved track. And the steering angle of a vehicle model (Case 2) with improved self-steering performance of wheelset is a little improved compare to previous vehicle model. But also Case 2 model is still insufficient compared with an objective steering angle and has its limit in steering performance. So to overcome this limit of steering performance of passive type railway vehicle, an active steering technology is being developed. In case of vehicle model with active steering system, the steering performance is improved remarkably compared to passive type vehicle model.

• 한국산학기술학회논문지
• /
• 제17권7호
• /
• pp.175-181
• /
• 2016

회전체는 질량 중심선이 축의 기하학적 중심선과 일치하지 않을 때 불평형이 발생한다. 윤축은 두 개의 차륜과 한 개의 차축으로 조립되어 철도차량을 주행시키는 회전체 역할을 하고, 차륜 재질의 불균일, 마모, 윤축 조립과정의 오차 등으로 인해 불평형이 발생할 수 있다. 또한 윤축은 축의 직경이 가늘고 고속으로 회전함으로 불평형 질량에 의한 진동의 영향이 더욱 두드러지게 나타나고 이로 인해 철도차량 고속 주행 시 주행안전성 및 주행거동에 영향을 미칠 수 있다. 그러므로 본 연구에서는 차륜 불평형이 고속철도차량의 동적 거동에 미치는 영향을 철도차량 다물체 동역학 해석 도구인 VI-Rail를 이용하여 해석을 수행하였다. 해석결과에서 차륜 불평형량이 증가할수록 철도차량 대차의 임계속도가 감소됨을 확인할 수 있었고, 차륜 불평형량이 주행 중 차량동적거동 악영향을 미침으로 고속주행에서는 반드시 차륜 불평형량에 대한 관리가 필요함을 확인할 수 있었다. 또한 이 연구로 차륜 불평형량의 정적 및 동적 관리 필요성을 국내 철도차량 운영기관에 제시하였다.