• Title/Summary/Keyword: Radius of curve

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Analysis of Comfort on Transition Curve based on the Measured Data (실측데이터에 의한 완화곡선 승차감 평가)

  • Choi, Il-Yoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.3573-3578
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    • 2015
  • Transition curves are located between curve and straight section in railway. These transition curves are vulnerable to the ride comfort of passengers and safety of a vehicle because lateral acceleration, lateral jerk and roll velocity increase as curvature and cant change along the transition curves. In this paper, ride comfort on the transition curve was calculated on the basis of lateral acceleration and roll velocity measurements. The evaluation of ride comfort was conducted according to the methodology specified in European Standard. The distribution characteristics of the comfort index were investigated for the korean conventional line from the evaluation results. The influence of the curve radius and the vehicle speed on the ride comfort index was also investigated. Finally, the relationship between ride comfort and the rate of cant changes on transition curves was analyzed.

A Study on Determination Method of Radius and Transition Curve Length for Optimum Design in Curve (곡선부 선형 최적설계를 위한 적정 곡선반경-완화곡선장 결정기법 연구)

  • Um, Ju-Hwan;Kim, Eun-Kyum;Yang, Sin-Chu
    • Journal of the Korean Society for Railway
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    • v.12 no.2
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    • pp.199-204
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    • 2009
  • In this paper, a method for determining the boundary conditions which derived from the random obstacles on the curves was presented. A simple computer program using this method is also developed. This determination method and program can be used for a good engineering tool in optimal curve design and an Radius-transition curve length $(R-L_t)$ combination within the permissible zone can be improved without any increased costs.

A Study on the Cant Setting in Railway Curve Section (철도곡선구간에 있어서 캔트 설정에 관한 연구)

  • 이남수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.11 no.1
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    • pp.1-6
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    • 1993
  • The cant has setted up wrong in a part of railway curve sections, occasionally confusion occur in curve maintenance. In this study, it is suggest effective maintenance method in railway curve section about the radius of curvature, cant successive diminution length, according to the investigation of cant value, compare and analysis with straight decrease in order theory.

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Classification of Middle Aged Women's Breast Shapes Using 3D Body Measurement Data (3차원 인체 측정치들을 이용한 중년 여성의 유방 형태에 따른 유형)

  • Lee, Hyun-Young;Hong, Kyung-Hee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.34 no.3
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    • pp.385-392
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    • 2010
  • The breast types of middle-aged women of 80A (formerly 80B) size were classified through a 3D scanned nude body. Thirty seven measurements including the radius of curvature, surface area, volume, surface length, and breast displacements were used as input variables. We extracted five main factors through the factor analysis of the measurements and classified 36 subjects into 3 clusters through the cluster analysis. As a result of the factor analysis, the size of the breast, breast sag, the curvature of the inner and the outer breast curve, the width of the breast, and the nipple direction were found as the main factors. For the results of the classification of breast types, Cluster 1 was characterized by narrow breast width and unsymmetrical under the breast curve, whereas Cluster 2 was a wide and sagged shape. Cluster 3 was classified into big breast volume and symmetrical under-breast curve. The results are useful to the product development of high quality brassieres which reflect the 3D characteristics of breast types of middle-aged women.

A Study on the Application of Extension Method in Railway Transition Curved Zone Considering Field Status (지형여건을 고려한 철도 완화곡선 연장방법의 적용성에 관한 연구)

  • Jeong Eui Hwan
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.22 no.4
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    • pp.391-400
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    • 2004
  • Railway curved zone have crucial effects on the speed of train. Length of transition curve is one of the important factor for alignment compatibility estimation in this sections, this value is decided by running speed and Cant. In this study, the extension method of transition curve is evaluated, based on the alignment of Jang Hang-Line, investigated field conditions of the sections in the curves exist. This research result show that changing of transition curve was proved by necessary to approximately two thirds of the curved sections, and method of fixing central point of track centerline and changing radius of curvature minimize the maximum shift in track centerline and deviation of radius, and also may be effective method for alignment suitability and speed up in case overall improvement is difficult.

A Study on the Assessment of Running Safety of Railway Vehicle passing through Curve (곡선부 통과 열차의 주행안전성 평가에 관한 연구)

  • Park, Kwang-Soo;Lee, Hi-Sung
    • Journal of the Korean Society for Railway
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    • v.10 no.5
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    • pp.492-498
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    • 2007
  • For the running safety assessment of Saemaul train passing through curves, an analysis model for multibody system has been developed. By using this model and ADAMS/Rail, sensitivity analyses depending on the variation of parameters related to the derailment coefficients have been conducted. At low speed, the derailment coefficient and the unload ratio of right wheel showed higher than left wheel, while those of left wheel showed higher than right wheel at high speed. According to decrease of curve radius, the derailment coefficient and the unload ratio were increased. When the length of transition curve was increased, the derailment coefficient was increased but there was no change on the unload ratio. According to the increase of cant, the derailment coefficient and the unload rate were increased.

A Study for Precision Equation and Transition curve of Vertical Curve (종곡선의 정밀식과 완화곡선에 관한 연구)

  • Shin, Soon-Ho;Kim, Yong-Eul
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.1676-1682
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    • 2008
  • The vertical curve of railway is installed in changing point where the gradient is more than a certain degree to ensure safe operation of train and comfort of passengers. As a result of CAD work with 3D coordination by using the existing equation, it was found that the simple equation about vertical curve installation suggested in the surveying engineering or railway regulations did not reflect theoretical curvature of circular curve in a case of steep grade and large vertical radius. In this study, for derive precision equation and transition curve about vertical curve, gradient parameters, equation of circles and transition curve equation were used, and it was verified by CAD that the derived equation is exactly satisfied with parameters of geometrical circular and transition curve. This equation could be used to provide more smoothing operation of train and comfort of passengers on vertical curves, especially in case that railway requires precision vertical alignment of track such as super high-speed railway, LRT or Maglev system.

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An evaluation of curve of Spee using cone beam computerized tomography in Korean (한국인에서 콘빔형 전산화단층영상을 이용한 스피만곡 평가)

  • Oh, Sang-Chun;Kim, Seul-Gi;Kim, Yu-Jin
    • Journal of Dental Rehabilitation and Applied Science
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    • v.30 no.2
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    • pp.93-101
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    • 2014
  • Purpose: The aim of this study is to investigate the typical shape of the curve of Spee in Korean and analyze the curve of Spee according to gender, age, and left and right. Materials and Methods: Among the patient of Wonkwang University Sanbon Dental Hospital taking cone beam computerized tomography, the images of 500 Koreans (311 males and 189 females) who qualifies the criteria of this study were selected and their curve of Spee were analysed in sagittal plane. Results: The mean radius of curve of Spee in Korean was 91.4 mm. There was statistically significant difference between male (94.6 mm) and female (86.1 mm) by gender, but not significant differences by age and between right and left side. Conclusion: Within the limitation of this study, the smaller radius (91.4 mm) of Korean than the 4-inch (101.6 mm) value advocated by Monson was meaned that it would be need to reconsider the application of the curve of Spee in all cases when occlusal plane is reconstructed in Korean.

Flange Wear of the High Speed Train (고속열차 차륜 플랜지 마모)

  • Lee Hisung;Kang Bu-Byoung
    • Tribology and Lubricants
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    • v.22 no.1
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    • pp.33-39
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    • 2006
  • During the high speed train operation in the conventional line, it was found to have extremely severe flange wear, due to the curvy routes. This paper looks at the actions that have been taken to bring the wear to an acceptable level. In particular, it have been presented for flange wear variation depending on curve radius, cant, transition curve length by using numerical method. And the impacts on the flange wear by the application of stick type solid lubricant are also presented.

Effect of the Impeller-Blade Radius of Curvature on the Performance of Centrifugal Pump (임펠러 곡율반경(曲率半徑)이 농용양수기(農用揚水機)의 성능(性能)에 미치는 영향(影響)에 관(關)한 연구(硏究))

  • Choi, K.H.;Kwon, S.H.
    • Journal of Biosystems Engineering
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    • v.13 no.2
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    • pp.18-27
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    • 1988
  • The basic model of impeller was developed for the theoretical analysis of performance. The developed model was tested with two different blade radius of curvature based on the pumping efficiency under the operating conditions in Korea. And the pump performance of the impeller was also tested for the various speeds. The results obtained are summarized as follows; 1. There was no significant effect on the different blade radius of curvatures on the discharge and pump efficiency. 2. Head and power requirement was increased in proportion to the blade radius of curvature. 3. In the mathematical approach of the blade radius of curvature, the method of involute curve was more recommendable as compared with the method of circular arc curve. 4. The pump efficiency of the model impeller developed based on the theoretical analysis increased about 10% more than that of the existing impeller.

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