• Title, Summary, Keyword: CWR

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Buckling Probability Evaluation Framework of CWR Tracks (장대레일 궤도의 좌굴확률평가 시스템)

  • Bae, Hyun-Ung;Han, Seung-Ryong;Choi, Jin-Yu;Lim, Nam-Hyoung
    • Proceedings of the KSR Conference
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    • pp.305-309
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    • 2010
  • The buckling behavior of CWR tracks is affected by the various parameters such as stiffness and geometry of track panel, ballast resistance, rail temperature, initial imperfection, and wheel load. Until now, CWR tracks were managed by the dichotomous logic (deterministic approach) despite these influence factors are having the nature of random variables. So, the design method and existing management process to prevent the track buckling can be very non-economic since the value of these influence factors to calculate the track buckling strength are selected by considering the worst track condition. In this study, buckling probability evaluation process is proposed which is based on the reliability index, AFOSM method, and limit state equation.

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Stability evaluation of CWR on the bridge with lead Rubber Bearing(LRB) (LRB 교좌장치를 사용한 교량의 장대레일 축력안정성 평가)

  • Yang Sin-Chu;Yun Cheol-Kyun;Lee Jin-Woo
    • Proceedings of the KSR Conference
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    • pp.787-792
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    • 2004
  • LRB(Lead rubber bearing) has small resistance force against slowly acting loadings such as temporal and creep loadings vice versa large resistance force against rapid loadings such as earthquake and braking loadings. By those mechanical characteristics, it has the advantage to reduce longitudinal load acting on abutments and piers, and moreover to in1prove the running stability of train by restricting the behavior of bridge under the required level. In this study, a stability evaluation method of CWR on the bridge with LRB is presented. Several parametric studies are carried to investigate how LRB contributes to the improvement of CWR stability.

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A Study on the Application of the Beam-Column Theory to Presume the Axial Force of the Continuous Welded Rail (장대 레일의 축력을 추정하기 위한 보-기둥 이론 적용에 관한 연구)

  • Lee, Woo-Chul;Ryu, Hyo-Jin;Lim, Nam-Hyoung;Lee, Chin-Ok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.6
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    • pp.159-168
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    • 2007
  • The problem of determination of axial force in continuous welded rail(CWR) has attracted a number of railroad engineers due to its practical importance in prevention of accidents related to buckling and pull apart. In this paper, we investigated the application of the beam-column theory to presume the axial force in CWR and proposed the development process of the prediction equation and model to presume the axial force in CWR.

A study on the Longitudinal Force Variation of CWR according to the Condition of Track Maintenance (궤도보수 작업 조건별 장대레일 축력변화에 관한 연구)

  • Won, Yong-Hoan;Kim, Kwan-Hyung;Kwon, Soon-Jung;Lee, Seung-Youl
    • Proceedings of the KSR Conference
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    • pp.99-105
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    • 2009
  • This research presents the method to decide proper locations for destressing of CWR using a non-destructive equipments to measure the longitudinal force(installation temperature) in CWR. The effect and necessity of destressing were analyzed by estimating changes of longitudinal force. The installation temperature was measured to find changes of longitudinal force in high speed and conventional lines before and after destressing or track maintenance at the locations where destressing was planed or where change of longitudinal force was expected during track maintenance. Past destressing was carried out within qualitative decision criteria. This research proposes the quantitative criteria to decide the priority order of the destressing locations reasonably by considering the difference of air temperature and stress free temperature during the track maintenances, the grade of ballast resistance force recovering and the length of destressing, etc.

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Characteristic of Additional Lateral Force Induced by Freight Car Loading CWR When Passing over Turnout and Curves (장대레일 화차의 분기부 및 곡선구간 통과시 추가횡압 발생에 관한 연구)

  • Kim, E.;Yang, S.C.;Lee, J.H.;Lee, J.D.
    • Proceedings of the KSR Conference
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    • pp.242-249
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    • 2002
  • This research suggests the assessment method of the additional lateral force caused bending moment of CWR when a freight car loading it is passing over turnout system or curves. The characteristics of lateral lone are analyzed by calculating the lateral pressure acting on the rails of conventional railway.

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Study on Determination of Optimal Speed of Freight Car Loading 300m CWR on KNR Line (국철구간 300m 장대레일 적재 화차의 적정주행속도 결정에 관한 연구)

  • Yang, S.C.;Kim, E.;Chung, W.J.
    • Proceedings of the KSR Conference
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    • pp.234-241
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    • 2002
  • In this study, a numerical method which assesses running stability of freight car loading 300m CWR and structural safety of conventional railway track when passing over curves and steel girder bridges is presented. Optimal speed of the freight car is suggest on the basis of numerical reviews for stability of derailment of the freight car and structural safety of track at weak points of the conventional line.

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A Study Running safety of the Freight Car Loading CWR on KNR Line (장대레일 적재 화차의 기존선구간 주행안전성 연구)

  • Kim, Jong-Oh;Yang, S.C.;Oh, Il-Geun;Lee, Hi-Sung
    • Proceedings of the KSR Conference
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    • pp.959-964
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    • 2007
  • In this study, it is offering a numerical method which assesses running safety of the freight car loaded CWR when passing through on the conventional railway by additional lateral load. It is suggested based on the numerical reviews of the safety against derailment after seeking the derailment coefficient estimated by wheel load-lateral force equation in the section that curve radius is small

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Three Dimensional Buckling Analysis of Continuous Welded Rail Track Under Thermal Load (온도하중을 고려한 장대레일 궤도의 3차원 좌굴 거동)

  • 강준석;임남형;양신추;강영종
    • Proceedings of the KSR Conference
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    • pp.471-478
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    • 2000
  • For many decades, the railway was constructed using tracks with jointed rails of relatively short lengths. The joints cause many drawbacks in the track and lead to signeficant maintenance cost. so, railroad engineers became interested in eliminating joints. Continuous welded rail(CWR) track has many advantages over the conventional jointed-rail track. but, in the case of the elimination of rail joints, it may cause the track to be suddenly buckled laterally by thermal loads. In this paper, firstly, 3-D CWR track model and CWRB program exactly considering the influence of tie are developed far linear static and buckling analysis using finite element method. Characteristics of CWR track model are using 7-dofs beam element as rail, Offset technic exactly considering centroid axies difference of track components(rail, rail-pad-fastener, tie), and Thermal gradient considering thermal difference of top flange and bottom flange in rail section.. second,, Through the static and linear buckling analysis by CWRB, Influences of various track components (rail, ballast, fastener, tie and so on..) on CWR track behavior and stability was characterized.

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Statistical Characteristics for Longitudinal Friction Behavior of Rail Fastening System for Concrete Track (콘크리트 궤도용 레일체결장치의 종방향 마찰거동에 대한 통계적 특성)

  • Bae, Hyun-Ung;Park, Sang-Jun;Yun, Kyung-Min;Park, Beom-Ho;Lim, Nam-Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7870-7877
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    • 2015
  • In the case of CWR (Continuous welded rail) located on the railway bridge, the CWR has additional axial force due to interaction of bridge and track. Therefore, the CWR tracks located on the bridge have to secure the safety of running train and CWR track through mitigating influence for interaction of bridge and track. The railway design guide in Korea (KR C-08080) provides a certain value for property of longitudinal friction behavior of rail fastening system that is major parameter of interaction behavior by applying European codes. However, in order to apply to domestic railway, it is necessary to review property characteristics of the rail fastening system in actual use. In this paper, the experiment for longitudinal friction behavior of rail fastener applied to concrete track on the railway bridge in Korea was carried out, and statistical characteristic for property of the rail fastener was analyzed from the result of the experiment.

Inhibitory Effects of Ethanol Extracts from Polygoni multiflori radix and Cynanchi wilfordii radix on Melanogenesis in Melanoma Cells (하수오와 백하수오의 에탄올 추출물에 의한 B16/F10 Melanoma 세포주의 멜라닌 생성 억제효과)

  • Seo, Hee;Seo, Geun-Young;Ko, Su-Zie;Park, Young-Hyun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.8
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    • pp.1086-1091
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    • 2011
  • Anti-oxidative activity and tyrosinase inhibitory activity of various ethanol extracts of Polygoni multiflori radix (PMR) and Cynanchi wilfordii radix (CWR) were compared to identify an anti-oxidant and whitening agent source from nature. We conducted an investigation into the anti-oxidant activities of PMR and CWR ethanol extracts by measuring total polyphenol content, total flavonoid content, and ABTS radical capacity. The total polyphenol contents of PMR and CWR were 17.31${\pm}$0.54 mg GA/eq g, and 2.75${\pm}$0.22 mg GA/eq g, respectively. The total flavonoid contents of PMR and CWR were 6.38${\pm}$0.39 mg naringine/eq g, and 1.34${\pm}$0.09 mg naringine/eq g, respectively. The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical decolorization of PMR and CWR were 96.89${\pm}$0.21% at 1 mg/mL and 93.49${\pm}$0.76% at 50 mg/mL. Melanoma cells were cultured with the PMR and CWR ethanol extracts for 48 hr, and total melanin content as a final product and the activity of tyrosinase, a key enzyme, in melanogenesis, were estimated. The PMR and CWR ethanol extracts increased melanin content and tyrosinase activity in a dose-dependent manner. These results suggest that PMR and CWR ethanol extracts could be useful as a skin whitening agent.