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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Railway
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Korean Society for Railway
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Volume & Issues
Volume 13, Issue 6 - Dec 2010
Volume 13, Issue 5 - Oct 2010
Volume 13, Issue 4 - Aug 2010
Volume 13, Issue 3 - Jun 2010
Volume 13, Issue 2 - Apr 2010
Volume 13, Issue 1 - Feb 2010
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Mechanical Properties of Joints according to Welding Methods and Sensitivity Analysis of FSW's Welding Variables for A6005 Extruded Alloy of Rolling Stock
Kim, Weon-Kyong ; Won, Si-Tae ; Goo, Byeong-Choon ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 131~138
Recently, extruded aluminium-alloy panels have been used in the car bodies in order to meet the needs for the speed-up and light-weight of the railway vehicles. Most of the car bodies were jointed by arc weldings, like GMAW (GasMetal Arc Welding) and GTAW (Gas Tungsten Arc Welding), but these weldings became fairly worse the mechanical properties of the junction than the base metal. Nowadays, FSW (Friction Stir Welding), which is superior to the arc weldings, has been applied in the railway vehicles. In this study, the mechanical properties of the joints in both FSW and GMAW for A6005 extruded aluminium-alloy sheets have discussed. In addition, the relationships between the welding conditions and the mechanical properties for the joint of FSW have analyzed through the sensitivity analysis. It can be concluded that the mechanical properties for the joint of FSW are better than those of GMAW and the welding speed is the most sensible welding condition in the process of FSW.
Equivalent Modeling Technique for 1-D Collision Dynamics Using 3-D Finite Element Analysis of Rollingstock
Park, Min-Young ; Park, Young-Il ; Koo, Jeong-Seo ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 139~146
In this study, a new equivalent modeling technique of rollingstock for 1-D collision dynamics was proposed using crash analysis of 3-D finite element model in some detail. To obtain good simulation results of 1-D dynamic model, the force-deformation curves of crushable structures should be well modelled with crash analysis of 3-D finite element model. Up to now, the force-deformation curves of the crushable structures have been extracted from crash analyses of sectionally partitioned parts of the carbody, and integrated into 1-D dynamic model. However, the results of the 1-D model were not satisfactory in terms of crash accelerations. To improve this problem, the force-deformation curves of the crushable structures were extracted from collision analysis of a simplified train consist in this study. A comparative study applying the suggested technique shows in good agreements in simulation results between two models for KHST.
Study on Buckling Instability of Expansion Tube using Finite Element Method
Choi, Won-Mok ; Kwon, Tae-Su ; Jung, Hyun-Sung ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 147~151
Since the kinetic energy is dissipated through plastic deformation energy generated in expanding process of the tube by a die. In order to successfully absorb the kinetic energy there should be no buckling in the expansion tube during expanding process. The buckling instability of the expansion tubes is affected by the initial boundary conditions, tube thickness and length. In this study, the effects of the tube thickness except length and initial boundary condition on the buckling instability are studied using a finite element method. In addition, Analysis procedure for nonlinear post-buckling analysis of expansion tube is established. There are three kinds of finite element analysis procedures for buckling analysis of expansion tube, quasi-static analysis, linear buckling analysis and nonlinear post-buckling analysis. The effect of the geometry imperfections defined as linear superimposition of buckling modes is considered in the nonlinear post-buckling analysis. The results of finite element analysis indicate that the buckling load increase with increase of thickness of tube and geometry imperfection. Finial buckling shapes are changed with respect to the geometry imperfection.
A Single-Phase Hybrid Active Filter for AC Electrified Railway Systems
Park, Han-Eol ; Song, Joong-Ho ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 152~158
Generally, the AC electrified railway systems have the power quality problems that are induced from the harmonic currents and the reactive power. This paper presents a single-phase hybrid active filter adopting a SRF(synchronous-reference-frame) control for improving power quality in the AC electrified railway systems. The single-phase hybrid active filter can compensate the harmonic currents and the reactive power through the proposed SRF control algorithm. The proposed control algorithm can extract the third and fifth harmonics through the MSRF(multiple-synchronous-reference-frames) which is used to apply the three-phase systems. Therefore, the hybrid active filter can compensates only the high-frequency harmonic currents whereas the passive filter compensates the low-frequency harmonic currents. Also, the proposed SRF control algorithm can compensate the reactive power by the closed-loop control. The Validity and the effectiveness of the proposed SRF control method for the hybrid active filter are illustrated through the simulation results.
Building TRMS S/W based on Reliability Centered Maintenance
Ahn, E.J. ; Lee, K.S. ; Lee, K.S. ; Kim, S.O. ; Yoo, D.Y. ; Kim, C.H. ; Yoon, H.S. ; Lee, I.H. ; Oh, S.H. ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 159~165
In this paper the TRMS (Tilting Rolling-stock Maintenance System) that applies the concept of RAM (Reliability, Availability, and Maintainability) and RCM (Reliability Centered Maintenance) to Preventive and Corrective Maintenance Policy for TTX (Tilting Train Express) will be discussed. We will briefly introduce the RCM concepts and discus show these concepts and procedures are implemented in the TRMS S/W. In the TRMS S/W there are four modules, System and Operations Information Module, FMECA(Failure Modes, Effects, and Criticality Analysis)module, RAM Information Module, and RCM Analysis Module. The System and Operations Information Module provides the user interface for collection of systems and operations related data and the FMECA module provides a groundwork for the RCM analysis. The algorithms to calculate the reliability and failure rate for Weibull distribution and formulae to calculate the task intervals and task costs are proposed in the RAM and RCM Analysis Module respectively. There is a good possibility of applying RCM to other rolling stock maintenance systems if the benefit that RCM can brings to the maintenance world is fully recognized.
A Study on the Design of Controller for Speed Control of the Induction Motor in the Train Propulsion System-2
Lee, Jung-Ho ; Kim, Min-Seok ; Lee, Jong-Woo ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 166~172
Currently, vector control is used for speed control of trains because induction motor has high performance is installed in Electric railroad systems. Also, control of the induction motor is possible through various methods by developing inverters and control theory. Presently, rolling stocks which use the induction motor are possible to brake trains by using AC motor. Therefore model of motor block and induction motor is needed to adapt various methods. There is Variable Voltage Variable Frequency (VVVF) as the control method of the induction motor. The torque and speed is controlled in the VVVF. The propulsion system model in the electric railroad has many sub-systems. So, the analysis of performance of the speed control is very complex. In this paper, simulation models are suggested by using Matlab/Simulink in the speed control characteristic. On the basis of the simulation models, the response to disturbance input is analyzed about the load. Also, the current, speed and flux control model are proposed to analyze the speed control characteristic in the train propulsion system.
A Study on the Design of Controller for Speed Control of the Induction Motor in the Train Propulsion System-1
Lee, Jung-Ho ; Kim, Min-Seok ; Lee, Jong-Woo ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 173~178
Electric railroad systems consist of supply system of electric power and electric locomotive. The electric locomotive is adapted to high speed driving and mass transportation due to obtaining high traction force. The electric locomotive is operated by motor blocks and traction motors. Train speed is controlled by suppling power from motor blocks to traction motors according to reference speed. Speed control of the electric locomotive is efficient by spending minimum energy between motor blocks and traction motors. Recently, induction motors have been used than DC and synchronized motors as traction motors. Speed control of induction motors are used by vector control techniques. In this paper, speed of the induction motor is controlled by using the vector control technique. Control system model is presented by using Simulink. Pulse is controlled by PI and hysteresis controller. IGBT inverter is used for real-time control and system performance is demonstrated by simulating the induction motor which has 210[kW] on the output power.
Investigation on the Temperature Characteristics of CWR for the Climate Change
Choi, Jin-Yu ; Lee, Gyu-Sei ; Bae, Hyun-Ung ; Park, Beom-Ho ; Lim, Nam-Hyoung ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 179~185
In order to secure safety for the buckling and fracture of continuous welded rail and improve the efficiency of maintenance work, it is very important that grasp the characteristics of rail temperature. Recently, the maximum air temperature in summer season rises gradually and the minimum air temperature in winter season is decreasing gradually due to the climate change. Therefore, these phenomenon influences in the change amount of yearly rail temperature and can cause change of laying and maintenance temperature. In this study, actual measurement of rail temperature including climatic factors is carried out by constructing the temperature and climate measurement system as realistic as possible. Through the intensive investigation of actual data, it is founded that the existing prediction formulas for rail temperature may be used only in certain climatic conditions (certain combination of climatic factors). It may be more reasonable that the rail temperature considering actual climatic factors in site is predicted on probabilistic approach.
The Experimental Study on the Effect of Track System on the Integral Behavior of Railway Bridge
Sung, Deok-Yong ; Park, Yong-Gul ; Choi, Jung-Youl ; Kim, Sung-Il ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 186~193
Track system and periodic live load are characteristics of railway bridges. In the design and construction of railway bridge, periodic live load increases the importance of dynamic behavior. And It is well known that behavior of railway bridge may be affected by track system in real bridge. Through experimental study, static and dynamic behaviors were investigated. Deflection and stress due to bending moment were measured, the location of neutral axis of each section, natural frequency, damping ratio were analyzed for each three track systems - girder only, installed ballast track system and installed concrete slab track system. According to measured values for the each type of track system, concrete track system increases the stiffness of bridge by 50%, and ballast system does by 7%, dynamic responses of structure change linearly with the magnitude of load and location of neutral axis of each sections varies with each track system. Damping ratio is almost equal without and with track. Therefore, the effects of track system on the integral behaviors of railway bridge can not be ignored in the design of bridge, especially in the case of concrete slab track system. So study of the quantitative analysis method for effects of track system must be performed.
A Study on Fire Resistance Character of a Tunnel and an Underground Structure
Yoo, Sang-Gun ; Kim, Jung-Joo ; Park, Min-Yong ; Kim, Eun-Kyum ; Lee, Jun-Suk ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 194~200
Recently, a longitudinal tunnel construction has increased because of subway construction extension, geomorphological effect and the development of construction Technologies etc. When the fire occurs in a tunnel and an underground structure, the many damage of human life and the economic losses are caused. In Korea, fire resistance character study of a tunnel and an underground structure is proceeding. However, when a concrete is exposed to high temperature, study of load carrying capacity reduction and stability evaluation for spalling of a concrete is not enough. Therefore in this study, fire resistance character of a concrete evaluated according to time heating temperature curve(RABT and RWS) and a result compared on virtual fire accident in order to apply fire scenario. Also this study performed thermo-mechanical coupled analysis of a FEM-based numerical technique and estimated fire-induced damage of a tunnel and an underground structure.
The Bending Fatigue Behavior Analysis of Rail by Bending Fatigue Test
Sung, Deok-Yong ; Park, Yong-Gul ; Go, Dong-Chun ; Lee, Si-Yong ; Min, Rak-Ki ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 201~207
The replacement criterion of rail by accumulated passing tonnage was estimated by the bending fatigue life of rail. In order to estimate the bending fatigue life, it is basically needed to analyze bending fatigue behavior on the rail. In this study, the bending fatigue test were performed for 50kg/m and 60kg/m rails, and test specimens were distinguished by new and used rails and by the types of welded rail such as base material, thermite weld, and gas pressure weld. Also, this study analyzed the fractured surface, the position of initial crack and the bending fatigue behavior (S-N curve). Therefore, it evaluated S-N curve for welded rails according to the fracture probability. The result from this study might be used essential data in order to estimate the bending fatigue life of rail by the accumulated passing tonnage.
Field Tests Investigating the Ground Borne Vibration Induced by Underground Railway Tunnel
Ahn, Sung-Kwon ; Bang, Eun-Seok ; Lee, Bae ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 208~213
This paper describes the instruments used, and the test procedures adopted, and the findings obtained from a research project aiming to investigate, via full-scale field tests, the ground borne vibration caused by underground railway tunnel constructed in hard rock. The ground borne vibration induced by high-speed trains (i.e. the Korea Train eXpress (KTX) services) with a speed of approximately 200km/hr was measured inside the borehole constructed in the close proximity to the KTX tunnel using 3-component borehole seismographs in order to investigate the wave propagation of ground borne vibration. This paper also discusses the limitation associated with the current practice of measuring ground borne vibration using conventional borehole seismograph.
Effectiveness of Reinforcement for Transitional Zone between Tunnel and Earthwork Using the Large Sleeper
Choi, Chan-Yong ; Lee, Jin-Wook ; Kim, Hun-Ki ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 214~221
The transitional zone between tunnel and earthwork is one of the most vulnerable areas site for railway lines and because of differential settlement due to different stiffness of each supporting layer, it has to conducted a maintenance work constantly. In this study, it is conducted to compare the effect of reinforcement by wheel load and displacement of the sleepers after existing sleepers are replaced with the large sleepers for 20m long in-field transitional zone. Also, numerical parametric study using multi-layer elastic method has been performed to compare rail force, settlement and stresses of ballast while varying size and space of the sleeper. The field test and numerical results show that replacing the large sleepers improves about 10% of total settlement and coefficient of wheel force than conventional sleepers. Effectiveness of improvement is about 9.3%, 4%, 14.5% for rail seat force, settlement of sleepers and ballast pressure respectively with size of sleepers.
Optimization for the Design Parameters of Electric Locomotive Overhaul Maintenance Facility
Um, In-Sup ; Cheon, Hyeon-Jae ; Lee, Hong-Chul ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 222~228
In this paper, we propose a optimization approach for the Electric Locomotive Overhaul Maintenance Facility (ELOMF), which aims at the simulation optimization so as to meet the design specification. In simulation design, we consider the critical path and sensitivity analysis of the critical (dependent) factors and the design (independent) parameters for the parameter selection and reduction of the metamodel. Therefore, we construct the multi-objective non-linear programming. The objective function is normalized for the generalization of design parameter while the constraints are composed of the simulation-based regression metamodel for the critical factors and design factor's domain. Then the effective solution procedure based on the pareto optimal solution set is proposed. This approach provides a comprehensive approach for the optimization of Train Overhaul Maintenance Facility(TOMF)'s design parameters using the simulation and metamoels.
Study on Incident Report System and Safety Culture in Railway
Chung, Byung-Hyun ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 229~235
Safety is an essential requirement for public transportation, especially for railway. Railway are more safety than other means of transportation, but railway accident that is mass transportation result catastrophic result if an accident occurred. Railway operators and government are many prior efforts to prevent accident, but it is impossible to eliminate accidents. Therefore, various measures to reduce accidents as possible, and they have taken, this paper will review incident report system and safety culture which are most important factors for preventing accident. In addition, incident reporting system and an independent accident investigation and accident prevention and safety systems would be needed to improve train operating companies and related agencies for the safety of the railway is a cultural ritual. Indeed, the settlement of avalid railway safety culture will most certainly prevent railway accidents. Therefore, in the railway company and the correct understanding of railway safety culture and against the settlement plan would be reviewed in this paper.
Changes in Healthcare Utilizations of Cancer Patients since the Launch of KTX
Kim, Jin-Hyun ; Lee, Jae-Hee ; Lee, Jin-Hee ;
Journal of the Korean Society for Railway, volume 13, issue 2, 2010, Pages 236~243
We examine the change in healthcare utilization pattern of cancer patients since the launch of KTX in 2004. It is found that during the year of 2004 and 2005 the rapid increase in the ratio of cancer patients' healthcare utilizations for the tertiary hospitals in Seoul to the total healthcare utilizations has accompanied the rapid decrease in the corresponding ratio for the tertiary hospitals in the local metropolitan areas under the influence of KTX while the corresponding ratio for the tertiary hospitals in the local cities with little influence of KTX on them has exhibited mild change. Since healthcare consumers' choice of hospitals can be characterized by "foot voting" action in the healthcare service market in Korea, such a phenomenon may have strong implication that the introduction of KTX may have affected substantially the inter-area healthcare utilization pattern by cancer patients by reducing various sorts of long-distance travel costs. Therefore, considering the potential contribution of KTX to the increase of cancer patients' accessibility to hospitals with higher qualities, support policies such as fare discount for low-income cancer patients in local areas may need to be taken into consideration where the well-designed fare discount program for low-income cancer patients may increase utilizations of KTX by lowincome cancer patients without incurring additional costs to running of KTX.