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김응천(Kim Eung-Cheon),이재안(Lee Jae-An),이하희(Lee Ha-Hee) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
Republic of korea has begun operating high speed train service according as KTX service operation starts in 2004. Also, EMU whose maximum speed is over 150 kph will be starting to service with electrification and improvement of existing railroad. Moreover, metropolitan electric railways have begun an express service to increase scheduled speed. Therefore, running resistance of rolling stock becomes more important factor effects on the performance. Running resistance of rolling stock is the factor which is necessary for the performance or operation plan of rolling stock, and it"s related to rolling friction, slip friction, drag force, gradient, acceleration, curvature, tunnel condition and so on. It is possible to be calculated by CFD (Computational Fluid Dynamics). However it is predicted by experimental equation from running resistance test because of the complex calculation and manifold variables. In this paper, studies about running resistance of rolling stock is introduced, and each term of experimental equation is studied through theoretical approximation. Also, running resistance of rolling stock is estimated by the result of running resistance test, and effects being related to friction, drag force, gradient is examined.
철도차량 객차의 제동성능 계산에 대한 방법 연구 (Calculating Braking Performance for Coaches)
김응천(Eung-Cheon Kim),은정일(Jung-Il Eun),최진(Jin Choi) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.5
Braking performance of a trainset that consists of a locomotive and several coaches and/or wagons is influenced by that of the locomotive as well as each coach or wagon. For trains to safely travel on a railway, trains must be provided with sufficient distance where to stop. Thus, replacing coaches or wagons needs calculating, measuring the braking performance such as a stopping distance or a deceleration. The task is further complicated if there are many kinds of trains with different braking performance characteristics. The accurate calculation is subject to acquire accurate information on the existing cars. Moreover, the initiation of braking by a driver or the geometry of the track affects as complicated factors. In this paper, based on the braking performance test conducted for US-SCRRA coaches, introduced several factors assumed to influence the result and the compensating methodology.
김응천(Eung Cheon Kim),이원철(Won Cheol Lee),배진욱(Jin Wook Bae) 한국철도학회 2012 한국철도학회 학술발표대회논문집 Vol.2012 No.10
철도 차량에는 차량 시스템 구성을 위한 기기장치들이 많이 설치되어 있으며, 이 중 1 ton이상의 중량기기 역시 설치 된다. 이 중량 기기들을 지지하는 볼트의 강도는 차량 안전상 매우 주요한 요소이며, 안전률을 고려한 볼트 재질 및 수량 산정이 매우 중요하다. 따라서, 본 연구에서는 볼트의 재질, 강도, 기기의 무게중심, 취부 개소 그리고 피로 응력 등을 고려하여 방향별 하중 조건에 따른 기기 취부용 볼트의 강도 적합성을 판단 할 수 있는 방법론을 제시 하였다. A lot of devices are mounted on rolling stocks for the system configuration and some of devices are greater than 1 ton. The strength of bolts to support heavy devices is one of the main factors from a safety point of view and the selection of the material or quantity of bolts is very important. Therefore, a methodology to evaluate the suitability of mounting bolts against the specified design load cases considering the material, strength, center of gravity, number of mounting points and the fatigue stress is provided in this paper.
이재안(Jae-an Lee),김응천(Eung-Cheon Kim),김대훈(Dae-Hun Kim) 한국철도학회 2012 한국철도학회 학술발표대회논문집 Vol.2012 No.10
ITX 청춘 차량은 운영최고속도 180km/h(설계속도 198km/h)의 성능을 갖는 8량 1편성의 열차로서 국내에서는 처음 적용되는 2층 열차가 편성 중간에 2량 적용되어 있어 화제가 된 차량이다. 기존의 국내 철도차량이 150km/h이하의 저속 차량과 300km/h이상의 KTX차량으로 나뉘어져 있으나, 180km/h급 대의 차량을 새로이 제작함에 따라 새로운 속도 영역대 차량에 대한 주행저항을 확인해야 할 필요성이 대두되었다. 본 논문에서는 ITX 청춘 차량이 본선주행시험 기간동안 수행되어진 주행저항 시험에 대한 진행과정과 결과, 주행저항식과의 관계에 대해 고찰하였다. ITX train is comprised of 8 Cars that have the performance the max operating speed, 180km/h (Design speed - 198km/h) and become a national topic of conversation because this train have two doubledecker cars. The existing train are divided by general train operated below 150km/h and KTX train operated over 300km/h in Korea. Because ITX train is operated at new speed range(180km/h), the running resistance should be checked by running test. In this paper, it shall be reported that the running resistance test process, result and relation with formula tested for the main line.
Bio-inspired Flow Sensor for Simultaneous Detection of Flowrate and Direction in Underwater
Le-Giang Tran,Eung-Cheon Kim(김응천),Woo-Tae Park(박우태) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
The demand to explore the underwater environment is strong for many research areas. This work presents a novel approach to measure the complex hydrodynamic flow around the unmanned underwater vehicles (UUVs). Since the hydrodynamic flow generally comprised of the flowrate and direction, we designed a flow sensor to simultaneously detect these two components. Inspiring from the blind cavefish’s neuromast, we proposed a simplified hair cell that can transfer the hydrodynamic force into pressure. Four piezoresistive (PRT) pressure sensors were equipped as sensing elements. The sensor can detect the flowrate and direction in the range from 24 mm/s to 117 mm/s with an angular resolution of 8°. The maximum sensitivity of the sensor reached 0.206 mV/mms<SUP>-1</SUP>. By using additive 3D printing technology, we were able to monitor the hydrodynamic flow. This bio-inspired flow sensor is expected to help maneuvering the UUVs.
열 분포를 고려한 Heating Plate 열선 간격 최적 설계
곽주환(Ju Hwan Kwak),김문영(Moon Young Kim),김응천(Eung Cheon Kim),김도열(Do Yeol Kim),장현수(Hyun Soo Jang) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
In this study, optimum design of heating line distance in photo resist bake oven was conducted for thermal distribution. Base line FV model and simplified model were developed for validation of base machine’s thermal distribution. Results of two models were compared for verifying feasibility of simplified model. Analysis area was divided by 3 parts through a result of graph which is derived from base line model analysis. Range of design variables was derived from measured value. Model modification was conducted for optimum design based on DOE. Objective function is minimizing of heat distribution on heating plate and optimization was conducted using RSM. Optimal design was confirmed that heat deviation was less than base heating line model.