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레이놀즈 응력모델을 이용한 압력구배가 있는 난류경계층의 유동장 해석
이성혁,유홍선,최영기,Lee, Seong-Hyeok,Yu, Hong-Seon,Choe, Yeong-Gi 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.3
Numerical study on turbulent and mean structures of a turbulent boundary layer with longitudinal and spanwise pressure gradient is carried out by using Reynolds-stress-model (RSM). The existence of pressure gradient in a turbulent boundary layer causes the skewing or divergence of rates of strain, which contributes to production of turbulent kinetic energy. Also, this augmentation of production due to extra rates of strain can increase the turbulent mixing and cause the anisotropy of turbulent intensities in the outer layer. This paper uses the Reynolds Stress Model to capture anisotropy of turbulent structures effectively and is devoted to compare the results computed by using RSM and the standard k-.epsilon. model with experimental data. It is concluded that the RSM can produce the more accurate predictions for capturing the anisotropy of turbulent structure than the standard k-.epsilon. model.
신장성 지오그리드 보강재의 인발저항특성 평가를 위한 시험 및 수치해석 기법
이성혁(Seong-Hyeok Lee),고태훈(Tae-Hoon Koh),이진욱(Jin-Wook Lee),황선근(Seon-Keun Hwang) 한국철도학회 2002 철도저널 Vol.5 No.2
Reinforced earth structure has been regarded as general structure in order to achieve efficient land utilization as well as securing safety in railway service lines in other countries, but there are no construction actual results in Korea. In this study, tile soil-geogrid interaction mechanism was investigated experimentally and numerical analysis was performed to predict Pull-out behaviour of geogrid embedded in reinforced earth body. This experimental data and analysis result can not contribute to understand the soil-geogrid interaction mechanism at soil-geogrid interface but also be used in design practice of the railway reinforced earth structures.
이성혁(Seong Hyeok Lee),정영남(Young Nam Jung),임상진(Sangjin Lim),조호진(Hojin Cho),임유진(Yujin Lim) 한국철도학회 2015 한국철도학회 학술발표대회논문집 Vol.2015 No.10
본 연구에서는 터널구간에 적용할 직결 아스팔트 노반 궤도의 최적 두께 결정을 위한 설계차트를 개발하기 위하여, 주요 설계인자로서 궤도구조형식, 윤중 및 속도, 년간 통과톤수(MGT), 재료 물성(원지반 및 콘크리트 보조도상 탄성계수), 아스팔트 노반층의 두께 등을 설정하였으며 이들 설계인자의 조합을 달리하면서 윤중 재하시 아스팔트 노반하면에서의 인장변형률을 ABAQUS 3D 구조해석을 통해 분석하였다. 구조해석 분석결과와 손상도 이론에 의한 Miner법칙을 활용하여 터널구간용 직결 아스팔트 궤도구조(단면구성)에 대응하는 설계수명(내구년한) 결정 설계차트를 개발하였다. In this study, primary design parameters such as types of track section, wheel load size, velocity, MGT, elastic modulus and thickness of each layers are defined for optimum design of asphalt thickness adapted in the asphalt trackbed foundation in tunnels. 3D FEA were performed using ABAQUS program to compute tensile strain under asphalt layer with different values of design parameters defined. Using Miners’ theory with computed structural analysis results, design charts to decide design life of asphalt trackbed foundation in the tunnels are produced.
이성혁(Lee Seong-Hyeok),이진욱(Lee Jin-Wook),최찬용(Choi Chan-Yong),황선근(Hwang Seon-Keun) 한국철도학회 2001 한국철도학회 학술발표대회논문집 Vol.- No.-
In many countries the slab track of railroads is mostly applied on the railroad bridges and tunnels, however it hasn"t been constructed in the tunnel in Korea. Presently the Korea highspeed railway construction authority is planning to construct slab track in the tunnels to minimize the cost of maintenance and repair. In this study, dynamic characteristics of the railroad roadbed which was constructed using crushed stones obtained from tunnel construction was investigated through the field investigation, real scale model test and numerical analysis. As a conclusion. the roadbeds built with the crushed stones produced at the tunneling site satisfy the requirement of roadbed in terms of displacement and earth pressure for the slab track in the tunnel.
광폭침목형 아스팔트콘크리트 궤도의 열차 주행 시 거동 분석
이성혁(Seong-Hyeok Lee),배영훈(Young-Hoon Bae),최영태(Yeong-Tae Choi),한두섭(Doo-Seop Han),정인균(In-Gyun Jeong) 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05
자갈궤도와 콘크리트 궤도의 장점을 결합하고 단점을 상호 보완한 신개념 궤도시스템인 아스팔트 콘크리트 궤도에 대한 연구를 수년간 수행하여 왔다. 그 동안의 연구결과를 바탕으로 국내 최초로 아스팔트콘크리트 궤도를 영업선에 시험 부설하여 현장설치 시험을 진행하고 있다. 본 연구에서는 시험 부설된 광폭침목형 아스팔트콘크리트 궤도에 대해 열차 주행 시 측정된 윤중, 횡압, 레일 저부 응력, 레일 및 침목의 수직변위를 이용하여 광폭 침목형 아스팔트콘크리트 궤도의 거동 특성을 분석하였으며, 분석 결과 광폭 침목형 아스팔트 콘크리트 궤도는 궤도 안전성을 만족하기 위한 요구 사항을 만족하고 있는 것을 확인하였다. Asphalt concrete track has been studied for a few years, which is a new concept railway track that combines the advantage between ballasted track and concrete track. Based on the results of the study, asphalt concrete track was inceptively constructed on the commercial line in Korea and field test is in progress. In this study, wheel load, lateral load, stress of rail bottom surface, vertical displacement of rail and wide sleeper were measured in wide sleeper type asphalt concrete track during train operation. The behavior of wide sleeper type asphalt concrete track was analyzed by the measured results. As a result of the analysis, it was confirmed that wide sleeper type asphalt concrete track was fitted to the requirements for track safety and stability.
이성혁(Seong-Hyeok Lee),전선표(Seon-Pyo Jeon),정우영(Woo-Young Jung),주부석(Bu-Seog Ju),박성민(Sung-Min Park) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.10
현재 국내에서 시공된 대부분의 궤도형태는 자갈 도상궤도이다. 자갈 도상궤도는 오랜 기간 동안 사용되어 왔지만 지속적인 궤도 유지보수가 필요함에 따라 유지 보수비가 많이 지출되는 경향이 있다. 기 개발된 콘크리트 도상궤도는 이런 유지보수비용이 절감이 되지만 초기 건설비용이 많이 드는 단점을 지니고 있다. 아스팔트 도상궤도는 콘크리트 도상궤도에 비해 초기 건설비가 적게 들며 유지보수 비용이 적게 든다는 장점으로 인하여 현재 국외에서 많은 연구가 진행되었고 현장시공이 되었기에 현재 국내에서도 원천기술 확보를 위하여 관련연구가 활발히 진행 중이다. 본 연구는 아스팔트 도상궤도에 적용될 새로운 콘크리트 직결침목에 대한 전단키 설계에 관한 연구이다. Ballast track has been used for a long time, and most tracks available in Korea are ballast track system. One of the drawbacks of using ballast track is the constant maintenance cost. Concrete track, which is the other type of track system, require less maintenance cost, but have high in front-end construction cost. Many researches were conducted to obtain the core technology for alternative track system in Korea: asphalt track system. Asphalt track requires less initial construction cost as well as subsequent maintenance cost than concrete track. Current study focused on the development of shear key against horizontal load on the direct fixation track, which would be applied to asphalt track system.