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Accelerated Newton-Raphson 방법에 의한 대형구조물의 자유진동수와 모우드형의 결정
김만철,이인원,Kim, Man Cheol,Lee, In Won 대한토목학회 1994 대한토목학회논문집 Vol.14 No.5
각종 구조물의 설계에 있어서 동적해석은 필수적이다. 이러한 구조물의 동적해석에 모우드 중첩법을 사용할 경우 고유치문제의 해석이 선행되어야 한다. 그러나 동적해석에 있어서 대부분의 노력, 즉 시간은 고유치와 그에 대응하는 고유벡터를 구하기 위하여 사용되기 때문에 보다 효율적인 고유치해법의 개발이 요구된다. 본 논문은 수치적 불안정성을 해소하고 수렴성을 향상시킴으로써 전체 해석시간을 줄이기 위해 Robinson-Lee 방법에 accelerated Newton-Raphson 방법을 적용한 고유치해법을 제시하였다. 제안방법의 효율성은 몇가지의 수치해석을 통해서 증명하였다. For the design of various structures, the dynamic analysis of the structures is essential. Eigenproblem must be first computed when the mode superposition method is used in the dynamic analysis of the structures. However, since most of solution time is spent on calculating the eigenpairs of the system, the development of more efficient solution method is required. The purpose of this paper is to present the efficient solution method that combines the Robinson-Lee's method and accelerated Newton-Raphson method to improve numerical stability and increase convergence. Effectiveness of the proposed method is verified through numerical examples.
간선철도 고속화를 고려한 자갈도상궤도구조 개량방안에 대한 실험적 연구
김만철(Man-Cheol Kim),배영훈(Young-Hoon Bae),박용걸(Yong-Gul Park) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.5
철도의 경쟁력 확보 및 지역균형 발전을 선도하고, 친환경, 녹색성장의 핵심 교통수단인 철도의 위상 강화를 위해 현재 간선철도에 대해 200km/h 이상으로 고속화를 추진하고 있다. 이에 따라 150km/h급으로 설계되어 운영중인 간선철도 자갈도상궤도에서는 궤도 부담력 증가로 유지보수의 증가가 예상됨에 따라, 간선철도 고속화를 고려한 유지보수저감을 위한 자갈도상궤도의 개량방안 정립이 요구된다. 본 연구에서는 KTX 산천을 이용한 속도 단계별 증속시험 및 회귀분석을 통해 230km/h 주행시 궤도에 작용하는 하중 특성(윤중 및 가진주파수)을 정립하였으며, 이를 국내에서 적용되고 있는 자갈도상궤도의 구성품을 조합한 자갈도상궤도구조 형식별 실대형 시험체에 재하하여 도출된 궤도침하 특성 및 건설비와 유지보수비를 고려한 경제성 분석을 통해 간선철도 고속화를 고려한 자갈도상궤도구조의 최적 개량방안을 정립하였다. With respect to mainline railway, the increase in speeds up to more than 200km/h is currently being promoted to secure the competitiveness of the railway, lead balanced regional development and enhance its status as a key means of transportation for eco-friendly and sustainable green growth. In this regard, as the maintenance costs are expected to increase due to higher burden of dynamic track forces on the ballasted track designed with 150km/h-class, there is a need to establish improvement measures for the ballasted track to reduce maintenance costs, considering the speed increase of the mainline railway. In this study, load characteristics (wheel load and excitation frequency) acting on the track when trains operate at the speed of 230km/h were investigated through a regression analysis and a speed increase test using the KTX-Sancheon, and the optimal improvement measures considering the speed increase of the mainline railway were established through the economic analysis considering the deduced track settlement characteristics as well as construction and maintenance costs by applying the load characteristics to fullscale specimens by type of ballasted track structures which combine components of the ballasted tracks applied in Korea.
기존선 고속화 구간 증속시험을 통한 노반 형식별 자갈도상궤도구조 상태 평가에 관한 연구
김만철(Man-cheol Kim),박용걸(Yong-gul Park),임형준(Hyoung-Jun Lim),박선희(Sun-Hee Park),류진영(Jin-Young Ryu) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.5
국내에서는 철도경쟁력 확보를 위해 현재 기존선에 대해 200km/h 이상으로 고속화를 추진하고 있다. 이에 따라 150km/급으로 설계되어 운영중인 기존선 자갈도상궤도에서는 궤도 부담력 증가로 유지보수의 증가가 예상된다. 본 연구에서는 속도 단계별 증속시험을 통해 궤도 부담력을 측정하여 고속화에 따른 궤도 부담력 예측식을 도출하였고, 노반 형식별 궤도지지강성과 도상계수를 분석하여 자갈도상궤도의 상태를 평가하였다. 또한 이들을 독일의 자갈도상궤도구조와 비교하여 유지보수 저감을 위한 기존선 고속화구간의 자갈도상 궤도에 대한 개량방안을 제안하고자 하였으며, 이러한 개량방안에 대해서는 추후 고속화 조건에 따른 실대형 시험을 통한 궤도침하 발생률 및 경제성 분석을 통해 구체화할 예정이다. The conventional railway lines was planed the speed up of over 200 km/h to ensure the competitiveness for a domestic railway. However the general ballasted tracks in a convention line was designed by the minor design class that was set on the design speed of tracks under 150km/m. Therefore, the conventional ballasted tracks was expected to increasing the maintenance cost due to increasing the dynamic track forces by increasing vehicle speed. In this study, the field tests were performed to evaluate that the influence the increasing vehicle speed on the dynamic track responses. Therefore, the prediction equation for dynamic track response was derived, and compared with the different substructure type such as earthwork, bridge and tunnel. The relationship between the track support rigidity, the ballast coefficient and the dynamic track response for various types of substructures currently employed in Korean convention railway line was assessed by performing field tests using actual vehicles running along the service lines. Field tests were performed on ballasted tracks with different substructure type, i.e., earthwork, bridge and tunnel. The experimentally measured track support rigidity and ballast coefficient were compared with the corresponding track support rigidity and ballast coefficient of German railway through field tests for the various substructure types on the service line. We found that the condition of ballast, substructure type and the corresponding track support rigidity and ballast coefficient directly affect the dynamic track response.
김만철(Man-Cheol Kim),황성호(Sung-Ho Hwang),황광하(Kwang-Ha Hwang),현상학(Sang-Hak Hyun) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.10
In this paper a flexible track modeling of turnout was developed and dynamic characteristics of turnout rails were analyzed when a vehicle passed through the turnout. The flexible track modeling is effective to the stiffness and durability design of turnout because it can capture the deformation and dynamic stress due to the collision of between wheels and rails when the vehicle move to the tongue rail. Also a more accurate running safety can be obtained by considering the interaction between wheel and rail deformation. Solid finite elements were used for variable cross-sections of rails and the variation of rubber stiffness was modeled. The proposed flexible track modeling in this paper was verified to be valid by comparison with the experiment of the turnout system.
김만철(Man-Cheol Kim),최배성(Bai-Sung Choi),김유희(Yu-Hee Kim),신수봉(Soob-ong Shin) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.10
Due to high-speed of trains the track deformation increases rapidly and may lead to track irregularities causing the track stability problem. To secure the track stability the continual inspection on track irregularities is required. The paper presents a methodology for identifying track irregularity using the NARX neural network considering non-linearity in the train structural system. A simulation study has been carried out to examine the proposed method. Acceleration time history data measured at a bogie were re-sampled to every 0.25m track irregularity. In the simulation study two sets of measured data were simulated. The second data set was obtained by a train with 10% more mass than the one for the first data set. The first set of simulated data was used to train the series-parallel mode of NARX neural network. Then the track irregularities at the second time period are identified by using the measured acceleration data. The closeness of the identified track irregularity to the actual one is evaluated by PSD and RMSE.
2차원 관절형 고속열차 모델을 이용한 차량/궤도/교량 상호작용해석
김만철(Kim Man-Cheol),양신추(Yang Sin-Chu),이종득(Lee Jong-Duk) 한국철도학회 1999 한국철도학회 학술발표대회논문집 Vol.- No.-
In this paper, the simplified method for 2-dimensional train/track/bridge interaction analysis is utilized in the analysis of dynamic behavior of bridges in which the eccentricity of axle loads and the effect of the toriosnal forces acting on the bridge are included for the more accurate train/track/bridge interaction analysis. Inverstigations mainly into the influence of vehicle speed on train/track/bridge interactions are carried out for the two cases. The first case is that only train and bridge are considered in the modelling and the other case is that train, track and bridge are considered.
고속선 터널내 궤도 형식에 따른 궤도 구성품의 진동 특성에 관한 연구
김만철(Kim Man-Cheol),장승엽(Jang Seung-Yup),강윤석(Kang Yun-Suk),한진석(Han Jin-Seok),한상철(Han Sang-Cheol) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-
In this paper, an experimental study is carried out to analyze the vibration characteristics of components of the ballast track and the slab track layed in HSL tunnels. According to vibration level test of ballast tracks and concrete tracks on HSL, the vertical vibration level of rails on concrete tracks is 6.2㏈ more than that on ballast tracks, and especially on 50~80㎐ frequency band, the difference is more than 6㏈. The orther track components according to track type are appeared to be smaller on the slab track than on the ballast track. Regarding car body vibration, 80㎐ component, which was not remarkable while running on open tracks, is considerably amplified in tunnels where concrete tracks are laid.