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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 19, Issue 4 - Aug 2016
Volume 19, Issue 3 - Jun 2016
Volume 19, Issue 2 - Apr 2016
Volume 19, Issue 1 - Feb 2016
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Analysis of the Polymer Properties and Sound Characteristics of Interlayer Films for Laminated Glass
Ko, Sangwon ; Hong, Jiyoung ; Sunwoo, Yerim ; Kim, Young Jun ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 1~10
DOI : 10.7782/JKSR.2016.19.1.1
To improve the sound insulation performance of laminated glass in high speed trains, it is beneficial to study the relationship between the characteristics of interlayer films and the acoustical performance. In addition to those of conventional PVB (polyvinyl butyral), the dynamic mechanical properties of PVB derivatives and PC (polycarbonate), which are candidates for interlayer films, were analyzed. We assumed that PVB-HEMU, which has a glass transition temperature (
) around room temperature and a large tan
(loss tangent) value, can be made to damp efficiently. The damping capability was tested utilizing sound transmission loss measurement and simulation under the identical structure of laminated glass in high speed trains. We also built a database for analysis of relations between interlayer film characteristics and acoustical performance; this was followed by the determination of sound transmission loss using the intensity technique and FEA.
Measurement and Analysis for the Upper Side Flow Boundary Layer of a High Speed Train Using Wind Tunnel Experiments with a Scaled Model
Oh, Hyuck Keun ; Kwon, Hyeok-bin ; Kwak, Minho ; Kim, Seogwon ; Park, Choonsoo ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 11~19
DOI : 10.7782/JKSR.2016.19.1.11
The flows around a high speed train are very important because they could affect the aerodynamic characteristics such as drag and acoustic noise. Especially the boundary layer of flows could represent the characteristic of flows around the high speed train. Most previous studies have focused on the boundary layer region along the train length direction for the side of the train and underbody. The measurement and analysis of the boundary layer for the roof side is also very important because it could determine the flow inlet condition for the pantograph. In this study, the roof boundary layer was measured with a 1/20 scaled model of the next generation high speed train, and the results were compared with full-scaled computational fluid dynamics results to confirm their validity. As a result, it was confirmed that the flow inlet condition for the pantograph is about 85% of the train speed. Additionally, the characteristics of the boundary layer, which increases along the train direction, was also analyzed.
Study for Prediction of Contact Forces between Wheel and Rail Using Vibrational Transfer Function of the Scaled Squeal Noise Test Rig
Lee, Junheon ; Kim, Jiyong ; Ji, Eun ; Kim, Daeyong ; Kim, Kwanju ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 20~28
DOI : 10.7782/JKSR.2016.19.1.20
Curved squeal noise may result when railway vehicles run on curved tracks. Contact between the wheels and the rails causes a stick-slip phenomenon, which generates squeal noise. In order to identify the mechanism of the squeal noise systematically, a scaled test rig has been fabricated. Knowledge of the contact forces between the wheels and the rail rollers is essential for investigating the squeal noise characteristics; however, it is difficult to measure there contact force. In this study, contact forces have been calculated indirectly according to the modal behavior of the subframe that supports the rail roller and the responses at specific positions of that subframe. In order to verify the estimated contact forces, the displacements at the contact points between the wheels and rail rollers have been calculated from the estimated forces; the resulting values have been compared with the measured displacement values. The SPL at the specific location has been calculated using the estimated contact forces and this also has been compared with the SPL, measured in a semi-anechoic chamber. The comparisons in displacements and SPLs show good correlation.
A Study on the Verification of Design Compatibility for a Europe Type Automatic Coupler Head according to TSI Certification Standards
Min, Kyeong Bin ; Park, Jin Kyu ; Kang, Ji Sung ; Kim, Ki Nam ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 29~37
DOI : 10.7782/JKSR.2016.19.1.29
The type approval system of the railway safety law, which was enforced in 2014, has been preferentially applied to the field of railway vehicles. The type approval system addresses railway vehicles and railway constituents. Unlike the previous system, it requires serial verification stages divided, in consecutive order, into verification of design compatibility and conformity and type test. These stages are in accord with international certification systems including TSI certification of the European commission. This study has been carried out to find and meet the design requirements for a coupler head, which is a part of the automatic coupler system; requirements were drawn from TSI and technical specifications that are subordinate to the domestic railway approval system. Through this study, it has been found that there exist 34 design requirements to acquire a complete coupler head. Among those requirements, 32 were verified by document inspection and two were able to be verified by performing FEA and gathering range analysis data.
Effect Analysis of Classical Line TI-21 type Audio Frequency Track Circuit from KTX Sancheon Return Current Harmonics
Choi, Jae Sik ; Kim, Hie Sik ; Park, Ju Hun ; Kim, Bun Gon ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 38~45
DOI : 10.7782/JKSR.2016.19.1.38
The power transformation system of High Speed rolling stocks like KTX-Sancheon has shown excellent control capacities in the areas of riding comfortability, switching efficiency, safety and energy consumption due to technical developments in power-electronics, high speed & large scale integrated semiconductors and microprocessors. However, harmonics from IGBT, a high speed switching device used in the Convertor & Invertor equipment of rolling stocks have given rise to various problems in transformer substations, signaling systems, data transmission systems and facility monitoring systems. Especially, TI21 non-insulated track circuits have malfunctioned due to the influence of returning current harmonics which were generated at around of integer times of the number of power transformation equipment in the frequency domain. This paper, measures and analyzes various schemes to analyze the traveling path of the returning current harmonics generated due to the relationship between the rolling stocks and track circuits on site. Ultimately, theseschemes will be used to design high speed rolling stocks, AF track circuits and a common grounding network.
Performance Assessment of a Temperature Control Unit used in a Lifecycle Testing System for LED Headlamps on Locomotives
Ohn, Jung-Ghun ; Jeong, Ki-Seok ; Chung, Jong-Duk ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 46~53
DOI : 10.7782/JKSR.2016.19.1.46
LED light sources have been known to have a long life and good energy efficiency compared to traditional light sources. Recently, headlamps using LED light sources have ensured the forward visibility and safe operation of high-speed rolling stock. However, assessing the lifespan of LED headlamps based on real test data is not easy because it depends on the multiple stress factors such as a fixed driving current, junction temperature, vibration and so on. Generally, LED headlamps have failed before their advertised life span mainly due to temperature. Thus, the performance assessment of a temperature control unit should be done before a life cycle test of LED headlamps. This study attempted to develop a prototype temperature control module for a lifecycle test system using a commercial LED headlight and verified the system through experiments.
Application of the Absorbing Boundary Condition in Moving Force Analysis of Asphalt Concrete Track
Lee, Seonghyeok ; Chung, Keunyoung ; Jung, Wooyoung ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 54~66
DOI : 10.7782/JKSR.2016.19.1.54
In this study, the absorbing boundary condition was adopted to prevent elastic wave propagation due to abrupt load condition changes in moving force analysis. It was proven to be effective in reducing inappropriate noise components. Furthermore, to verify whether fixed point excitation in a laboratory test can simulate train movement effectively, the results of dynamic analysis for fixed point excitation and moving force conditions were analyzed. The dynamic stability of an asphalt track structure under a KTX train condition was also studied. Additionally, the dynamic safety of asphalt tracks was verified by comparing the results of a moving force analysis under a KTX train load and a quasi-static analysis under the design standard Korean train load.
3D Dynamic Finite Element Analysis and Corresponding Vibration of Asphalt Track Considering Material Characteristics and Design Thickness of Asphalt Concrete Roadbed Under Moving Load
Lee, SeongHyeok ; Seo, HyunSu ; Jung, WooYoung ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 67~76
DOI : 10.7782/JKSR.2016.19.1.67
The asphalt-concrete trackbed system has many advantages in terms of maintenance and economics. However, methods to investigate practical use corresponding to the development of the trackbed system must be developed. The primary objective of this study was to evaluate the dynamic performance of the asphalt system in accordance with both the elastic and viscoelastic material characteristics and design thickness of the asphalt trackbed. More specifically, in order to reduce the uncertainty error of the Finite Element(FE) model, a three-dimensional full scale FE model was developed and then the infinite foundation model was considered. Finally, to compare the condition of viscoelastic materials, performance evaluation of the asphalt-concrete trackbed system was used to deal with the dynamic amplification factors; numerical results using isotropic-elastic materials in the FE analysis are presented.
Cost Analysis of VVVF Inverter Train Based on Life-cycle to Determine the Introduction Timing of New Trains
Lee, Kwang-Sub ; Lee, Chan Woo ; Yang, Keun-Yul ; Min, Jae Hong ; Shin, Jong Jin ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 77~86
DOI : 10.7782/JKSR.2016.19.1.77
Before urban railway vehicles reach their design life-span, operating agencies should determine when to buy new vehicles. Previous LCC (Life Cycle Cost) studies were limited because they independently focused on existing vehicles based on costs that directly impacted only the operating agency without considering effects such as social costs and the reduction of maintenance costs. Thus, it is difficult to systematically determine when to buy new vehicles. This study investigated the operating and maintenance related costs, especially from additional expenses and social costs due to unexpected vehicle failures and safety accidents, and did an economic analysis of scenarios with different discount rates. Considering that the public is very concerned about safety after the Sewol ferry accident, additional costs, which include social costs, should be included in the analysis. This study shows that the economic priority of scenarios may change depending on whether those costs are included and on the discount rate. The results of this study can help in the decision-making process for the planning and buying of new trains.
Application of Random Regret Minimization Model in the Context of Intercity Travel Mode Choice
Jin, Woo-Jeong ; Lee, Jang-Ho ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 87~96
DOI : 10.7782/JKSR.2016.19.1.87
The multinomial logit model, based on random utility maximization (RUM) theory, has been the predominant model used in travel mode choice contexts. In this paper, the travel mode choice model based on random regret minimization (RRM) theory is proposed as an alternative to the RUM model, and the applicability of the RRM model is examined. The presented model is applied to the case of inter-city travel mode choice in Korea. The empirical results show that the RUM model and RRM model have parameters that are consistent with the intuition. The goodness of fit statistics in the RRM model improved compared with the results of the RUM model. Consequently, these results show the possibility of using the RRM model in the context of travel mode choice.
A Study on Expansion of Inland Railway Use For Container Cargo
Choi, Kyoungsuk ; Xia, Tongshui ;
Journal of the Korean Society for Railway, volume 19, issue 1, 2016, Pages 97~108
DOI : 10.7782/JKSR.2016.19.1.97
Over 80% of Korea`s cargo transport relies on public roads. Such over-reliance has created a range of social problems including environmental damage. Korea thus faces an urgent need to establish an alternative mode of cargo transportation. In view of the changing international logistics environment, railway is clearly a superior mode of transport. The prerequisite task today for Korea is to enhance the competitiveness of inland railway by switching to railway and spurring new demand for cargo. This study examines inland railway cargo transport from the demand perspective. Specifically, through the use of a survey, the study identifies key factors influencing the decisions of container shippers regarding the use of railway for cargo transport. The survey responses were statistically tested using Smart PLS structural equation modeling. The results indicate that attitude toward railway use had the strongest influence on choice, while the key variable affecting attitude formation was cost.