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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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Journal DOI :
Korean Society for Railway
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Volume & Issues
Volume 18, Issue 6 - Dec 2015
Volume 18, Issue 5 - Oct 2015
Volume 18, Issue 4 - Aug 2015
Volume 18, Issue 3 - Jun 2015
Volume 18, Issue 2 - Apr 2015
Volume 18, Issue 1 - Feb 2015
Selecting the target year
Optimal Design for the Nose Shape of Commercial High-speed Train Using Function of Train Configuration
Kwak, Minho ; Yun, Suhwan ; Park, Choonsoo ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 279~288
DOI : 10.7782/JKSR.2015.18.4.279
Using the Vehicle Modeling Function, which can model various 3D nose shapes, nose shape optimization is performed to reduce the aerodynamic drag of the KTX Sancheon. 2D characteristic shapes of the KTX Sancheon nose were extracted and a base model of the KTX Sancheon was constructed for design optimization using the Vehicle Modeling Function. The design space was constructed with the base model and does not violate the shape constraints of commercial trains. Through nose shape optimization with the Broyden-Fletcher-Goldfarb-Shanno algorithm, the aerodynamic drag of the optimized shape was reduced by 6% compared to that of the base model. The longer nose and sharper edge of the optimized shape weaken the vortices behind the last car and can reduce the aerodynamic drag.
Numerical Analysis of Rail Noise Regarding Surface Impedance of Ground by Using Wavenumber Domain Finite and Boundary Elements
Ryue, Jungsoo ; Jang, Seungho ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 289~300
DOI : 10.7782/JKSR.2015.18.4.289
An important source of noise from railways is rolling noise caused by wheel and rail vibrations induced by acoustic roughness at the wheel-rail contact. In conventional approaches to predicting rail noise, the rail is regarded as placed in a free space so that the reflection from the ground is not included. However, in order to predict rail noise close to the rail, the effect of the ground should be contained in the analysis. In this study the rail noise reflected from the ground is investigated using the wavenumber domain finite element and boundary element methods. First, two rail models, one using rail attached to the rigid ground and one using rail located above rigid ground, are considered and examined to determine the rigid ground effect in terms of the radiation efficiency. From this analysis, it was found that the two models give considerably different results, so that the distance between the rail and the ground is an important factor. Second, an impedance condition was set for the ground and the effect of the ground impedance on the rail noise was evaluated for the two rail models.
Analysis of RTM Process to Manufacture Composite Bogie Frame Considering Fiber Orientation
Kim, Moo Sun ; Kim, Jung-Seok ; Kim, Seung Mo ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 301~308
DOI : 10.7782/JKSR.2015.18.4.301
To reduce the weight of a railroad vehicle, a bogie frame skin is considered for manufacture using an RTM process and composite material. Compared to other processes, RTM has merits in that it demands only simple manufacturing facilities and can produce a large and complex structure in a short cycle time. On the other hand, it is important to determine the proper number and locations of gates and vents to prevent void formation inside a structure. In this study, we numerically predicted the flow pattern in a bogie frame skin during the RTM process by distinguishing the permeability of a fiber mat as isotropic or anisotropic. Using the results, we analyzed the RTM process conditions of the bogie frame to predict skin void formation, mold filling time, and optimum location of vents depending on the permeability conditions.
A Study on the Contribution of Exterior Devices to Running Resistance in High-Speed Trains
Oh, Hyuck Keun ; Kwak, Minho ; Kwon, Hyeok-bin ; Kim, Sang-soo ; Kim, Seogwon ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 309~316
DOI : 10.7782/JKSR.2015.18.4.309
The contribution of exterior devices such as bogie fairings and pantographs to running resistance was estimated on the basis of coasting tests at up to 350 km/h with the help of the Korean Next Generation High speed train (HEMU-430X). In order to assess the reduction of air resistance by nose car`s bogie fairing, coasting tests were conducted with a removable bogie fairing at various speed ranges. And, the contribution of the pantograph to air resistance was also estimated with coasting tests that include the pantograph`s rising and descent modes. The linear regression method was used to examine decelerations from time-velocity data and the equation of resistance to motion is proposed from the deceleration data. From the aerodynamic term of the equation of resistance to motion, the contribution to air resistance by nose car`s bogie fairing and pantograph was estimated. The results show that the air resistance was reduced by about 3.8% by the nose car`s bogie fairing. And, the 3.9% increase of air resistance by the pantograph (open knee mode) has been found.
A Study on Application for Super Speed Maglev Railway of System Engineering Technology
Han, Young-Jae ; Jo, Jung-Min ; Lee, Jin-Ho ; Kim, Dong-Hyun ; Lee, Chul-Ung ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 317~324
DOI : 10.7782/JKSR.2015.18.4.317
A super speed maglev is a complicated system integrating electric, electronic, mechanic, civil and construction engineering. So, there must be an integrative system to monitor and manage operation requirements and standard features of each subsystem and the interfaces between each technology. As an indispensable part that can ensure whole system performance, a secure interface for each individual subsystem is an important management item of system engineering. By securing the interface performance of each individual subsystem, system failure can be effectively prevented in advance. Based on system engineering techniques, improvement of security and reliability for a super speed maglev is described in this research.
Grid-Connected Control of Hybrid Energy Storage
Lee, Eon-Seok ; Kang, Byeong-Geuk ; Choi, Yong-Oh ; Chung, Se-Kyo ; Oh, Se-Seung ; Chae, Suyong ; Song, Yujin ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 325~334
DOI : 10.7782/JKSR.2015.18.4.325
This paper deals with a control method for a hybrid energy storage system (ESS) with a battery and super capacitor for grid-connected operation. To improve the grid regulation and to minimize the depth of discharge of the battery, control algorithms for the hybrid ESS are proposed. A p-q control with predictive current control is used for the inverters for the super-capacitor and the battery. To verify the effectiveness of the proposed control method, simulation studies using the PSIM and RTDS are carried out for the actual grid model.
A Study on Switching Power Measurement of an Electrical Point Machine Using a Sensor
Lee, Jong-Hyun ; Kim, Yong-Kyu ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 335~343
DOI : 10.7782/JKSR.2015.18.4.335
The role of the turnouts installed on the points of railway branches and intersections is to safely switch the directions of trains. In case of abnormal forces applied to the turnouts due to extreme operating conditions, it is difficult in the current system to conduct accurate diagnosis and measuring. Moreover, the existing measurement devices for turnout switching power are mostly based on foreign technologies, which provide only limited information on the switching power; this information is insufficient for effective monitoring and maintenance. In this paper, through an analysis of the characteristics of the switching and locking function, the problems in turnout power measurements of current electrical point machines in Korea are examined. And based on the results, a new sensor-based method for measuring switching power is proposed.
A Study of BIM Delivery Model for Railway Construction Project using BIM Function Breakdown Structure
Kim, Young-Hwan ; Kim, Hyeon-Seung ; Kang, Leen-Seok ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 344~353
DOI : 10.7782/JKSR.2015.18.4.344
Recently, the utilization of the BIM system has been extended to cost and resource simulation, visualized management of construction site information and application of augmented reality including basic 3D modeling. Therefore, various BIM functions are being developed for practical applications. However, since clear classification criteria and knowledge information of BIM functions are not sufficient for field engineers, it is difficult to identify the necessary BIM functions for a construction project. This study suggests a BIM function breakdown structure considering the individual functional properties and a process model that can be ordered by applying BIM in a railway construction project. The proposed delivery model is used to obtain a practical utilization of BIM by analyzing features applicable to railway construction projects; model is verified using a case project.
Laboratory Test for Permanent Settlement Behavior of Geo-materials used in Railway Considering Grain size distribution and Water content
Lee, Sung Jin ; Lee, Il Wha ; Lee, Su Hyung ; Eum, Ki Young ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 354~362
DOI : 10.7782/JKSR.2015.18.4.354
Since allowable settlement of concrete slab track is about 30mm, a lot of attention must be paid to the settlement of the earthwork (reinforced trackbed, upper subgrade, under subgrade) under the concrete track. To this end, more experimental data should be accumulated through tests for these materials. In this study, we evaluate the long-term settlement of reinforced trackbed and subgrade materials using factors such as repeated loading conditions, water content, and grain size distributions in a large triaxial test and a large oedometer test. In cases in which the performance of the reinforced trackbed layer meets the design criteria, the settlement caused by train load was considerably small. But, when the water content increases in the subgrade, unexpectedly large settlement might occur for certain grain size distributions of the subgrade materials.
Dynamic Interaction Analysis of Train-bridge Considering Rail-wheel Contact Mechanism
Min, Dong-Ju ; Kwark, Jong-Won ; Kim, Moon-Young ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 363~373
DOI : 10.7782/JKSR.2015.18.4.363
The purpose of this study is to develop a nonlinear algorithm for the dynamic interaction analysis of KTX trains and bridge girders with consideration of separation and flange contact phenomena between wheel and rail. For this, three interaction models between wheel-rail are implemented and compared through numerical examples. That is, the spring model and the non-jump model are briefly explained, and a nonlinear contact model is then proposed to accurately simulate interaction forces of the train-bridge system. Dynamic interaction analysis of a simply supported girder and trains is performed and the analyzed results are presented and compared for the proposed contact model and the other model types. Particularly, flange contact phenomena in the nonlinear contact model are demonstrated under a specific condition.
Arrival Delay Estimation in Bottleneck Section of Gyeongbu Line
Lee, Jang-Ho ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 374~390
DOI : 10.7782/JKSR.2015.18.4.374
This research shows the relationship between the number of trains and the probability of trains with arrival delay and suggests way to estimate the benefits of improved punctuality in a bottleneck section of the Gyeongbu Line. The arrival delays of high-speed and conventional trains were estimated using the train operation data of KORAIL. Linear regression models for the probability of trains with arrival delay by train type are presented in this paper. The probabilities of trains with arrival delay were more affected by the number of conventional trains than by the number of high-speed rail trains. For the empirical analysis, a project for increasing the capacity in the Seoul~Geumcheongu office section was tested. The benefits of the improved punctuality were estimated to be 4.2~4.5 billion Korean won every year. This research has some limitations but it can help evaluate more precisely the feasibility of the project of increasing the capacity in bottleneck sections.
A Study on the Influence Factor Relationship of the Railway Tourism Policy for Job Satisfaction
Kim, Jung-Phyung ;
Journal of the Korean Society for Railway, volume 18, issue 4, 2015, Pages 391~400
DOI : 10.7782/JKSR.2015.18.4.391
This research used a survey of 350 staff members working at Korail with the purpose of analyzing influence factors for the railway tourism policy for job satisfaction; results were presented for the proposed factor. First, we selected the influence factor through precedent research related to the railway tourism policy. Second, the selected influence factor and the extent of satisfaction were used to determine whether or not any kind of difference existed according to individual attributes of the railway employees. Finally, we analyzed what the influence factor was between the category factor and the sub-category factor. In conclusion, it was found that government subsidy had a meaningful correlation with infrastructure expansion and the improvement of the railway business as it is connected to tourism efficiency. Human resources have a meaningful correlation with the needs of educational institutions and the retaining of talent. Railway tourism production has a meaningful correlation with railway tour production as it is conducted to satisfy tourists and the consortium. The shift of viewpoint has a meaningful correlation with the escape from the peace-at-any price principle and demand forecasting.