• 한국소음진동공학회논문집
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• 제15권1호
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• pp.29-38
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• 2005

The track pull-in behavior analysis in an optical disk drive (ODD) using plane phase and the evaluations for effecting parameters of it are discussed. Track pull-in, track capture procedure to do track following control, is a key factor to increase data transfer rate. First, the relative velocity between the beam spot of an optical pick-up and the target track of an optical disk is analyzed during the track pull-in procedure. In this process, it is showed that the track error signal has nonlinear characteristics which are depending on the time. Second, Runge-Kutta method to solve the nonlinear equation is applied to find the track pull-in behavior, and some optimal parameters to get stable and fast pull-in condition are obtained. Then, the phase plane analysis for track pull-in procedure is presented. Finally, some comments for the simulated results are discussed briefly.

• 대한토목학회논문집
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• 제12권1호
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• pp.97-105
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• 1992

본(本) 연구(研究)는 300 km/h 내외의 속도영역(速度領域)에서 운행(運行)되고 있는 고속열차(高速列車)의 불규칙(不規則)한 동적(動的) 윤중변동(輪重變動)을 해석(解析)하여 고속철도궤도(高速鐵道軌道)에서의 대책(對策)과 궤도(軌道) 각(各) 구성요소(構成要素)들의 구조설계(構造設計)를 위하여 종래의 연구(研究)에서 윤중변동(輪重變動)에 관련이 있다고 생각되어 온 차량(車輛)의 스프링하질량(下質量) 및 궤도틀림이외에 레일지지(支持)스프링계수(係數)와 진동감쇠계수(振動減衰係數) 등(等)을 포함하여 보다 정량적(定量的)인 해석(解析)을 시도(試圖)하였다. 특히 차량(車輛)의 동적(動的) 윤중변동(輪重變動)에 대한 궤도부분(軌道部分)의 주(主)된 역할(役割)은 레일지지(支持)스프링계수(係數)와 진동감쇠계수(振動減衰係數)에 있으므로 이에대한 궤도(軌道)의 각(各) 구성요소별(構成要素別) 특성(特性)을 보다 분명(分明)히 하기위하여 충격(衝擊)에 의한 레일지지계(支持系)의 동적(動的) 응답(應踏)을 역학(力學)모델 설정(設定)을 통하여 이론적(理論的)으로 해석(解析)하고 실물궤도(實物軌道)에서의 시험(試驗)에 의하여 종래 확실하게 밝혀지지 않았던 이들 궤도특성치(軌道特性値)를 산출(算出)하였다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.485-492
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• 2000

In the rail facilities the rail track consists of rail tie fastening accessories and bed,. The rail track is largely divided into Ballast Bed Track(BBT) and Concrete Bed Track(CBT) according to the type of bed. In this thesis among Concrete Bed Track slab track which is used for the Japanese high speed railway is a target of this study. Dynamic analysis by using finite element method are performed. where moving rain load is periodic function. Then through parametric study some conclusions are obtained as follow. Cement Asphalt Mortar(CAM) affects contrary mechanical behavior to rail and slab greatly. Therefore change of CAM spring coefficient should be handled with care, For slab thickness thin slab is more profitable to reduction of vibration of rail than thick one but mechanical capacity of slab is deteriorated, Improved structural type is proposed then structural analysis is performed for this one. This type is effective to reduction of vibration of railway system.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.493-598
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• 2000

In the rail facilities, the rail track consists of rail, tie, fastening, accessories and bed. The rail track is largely divided into Ballast Bed Track (BBT) and Concrete Bed Track (CBT) according to the type of bed. In this thesis, among Concrete Bed Track, slab track, which is used for the Japanese high speed railway, is a target of this study. Dynamic analysis by using finite element method are performed where moving train load is periodic function. Then through parametric study, some conclusions are obtained as follows. Cement Asphalt Mortar (CAM) affects contrary mechanical behavior to rail and slab greatly. Therefore, change of CAM spring coefficient should be handled with care. For slab thickness, thin slab is more profitable to reduction of vibration of rail than thick one but mechanical capacity of slab is deteriorated. Improved structural type is proposed, then structural analysis is performed for this one. This type is effective to reduction of vibration of railway system.

• 한국철도학회논문집
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• 제13권2호
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• pp.186-193
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• 2010

철도교에서는 일정한 간격의 축중을 가지는 차량하중이 반복적으로 재하되므로 정적성능과 더불어 동적성능이 매우 중요하다. 또한 철도교의 상부에 부설되는 궤도시스템은 교량의 정 동적 성능에 영향을 주는 것으로 알려져 있다. 본 연구에서는 실제 궤도시스템을 적용한 거더시험체를 제작하여 궤도시스템에 따른 교량의 정 동적거동을 분석하였다. 정적거동 분석에서는 교량 처짐 및 응력을 검토하고 중립축위치를 분석하였으며, 동적거동 분석에서는 고유진동수, 감쇠비, 하중크기, 하중진폭에 대한 영향을 궤도시스템별로 검토하였다. 궤도부설에 따른 정적처짐 변화검토를 통해 궤도 부설전에 비해 자갈궤도는 약 7%, 콘크리트궤도는 약 50%의 강성 증가 효과가 있음을 확인하였고, 궤도 부설 시 교량의 고유진동수가 낮아졌으나 감쇠비 변화는 없는 것으로 분석되었다. 또한, 최대하중 크기가 증가할수록 철도교량의 동적응답(처짐 및 가속도)이 선형적으로 증가하였으며, 하중진 폭은 공진 시 교량의 동적응답을 크게 증가시키는 것으로 분석되었다. 따라서, 자갈궤도는 교량의 강성을 일정 부분 증가시키고, 콘크리트궤도의 경우 자갈궤도 부설 교량에 비해 상당한 강성기여도를 가지고 있음을 실험적으로 입증하였으나, 정량적인 강성기여도의 크기는 자갈궤도 및 콘크리트궤도의 설계값에 따라 상이할 수 있기 때문에 이를 적용할 수 있는 궤도의 질량 및 강성기여도 분석방법 개발이 필요할 것으로 판단된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.379-384
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• 2009

It is of great importance to assure the running safety and ride comfort in designing the floating slab track for the mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety and ride comfort, and then, the behavior of train and track at the transition zone between the floating slab track and the conventional concrete slab track according to several main design variables such as spring constant, damping coefficient, spacing and arrangement of isolators and slab length, using the dynamic analysis technique considering the train-track interaction. The results of numerical analysis demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the vertical vibration acceleration of the train body, wheel-rail interaction force, rail bending stress and uplift force. The increase becomes higher with the decrease of the spring constant of isolators and the increase of the isolator spacing, but the damping ratio does not significantly affect the behavior of train and track at the transition. Therefore, to assure the running safety and ride comfort, simultaneously increasing the effectiveness of vibration isolation, it is effective to minimize the relative vertical offset between the floating slab and the conventional track slab by adjusting the spring constant and spacing of isolators at the transition.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.414-421
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• 1999

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.

• Structural Engineering and Mechanics
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• 제82권1호
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• pp.1-16
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• 2022

This work elaborately investigates the influences of the guideway geometry parameters and track irregularity on the dynamic performances of the suspended monorail vehicle-guideway system (SMVGS). Firstly, a spatial dynamic analysis model of the SMVGS is established by adopting ANSYS parameter design language. Then, the dynamic interaction between a vehicle with maximum design load and guideway is investigated by numerical simulation and field tests, revealing the vehicle-guideway dynamic features. Subsequently, the influences of the guideway geometry parameters and track irregularity on the dynamic performances of the SMVGS are analyzed and discussed in detail, and the reasonable ranges of several key geometry parameters of the guideway are also obtained. Results show that the vehicle-guideway dynamic responses change nonlinearly with an increase of the guideway span, and especially the guideway dynamic performances can be effectively improved by reducing the guideway span; based on a comprehensive consideration of all performance indices of the SMVGS, the deflection-span ratio of the suspended monorail guideway is finally recommended to be 1/1054~1/868. The train load could cause a large bending deformation of the pier, which would intensify the car-body lateral displacement and decrease the vehicle riding comfort; to well limit the bending deformation of the pier, its cross-section dimension is suggested to be more than 0.8 m×0.8 m. The addition of the track irregularity amplitude has small influences on the displacements and stress of the guideway; however, it would significantly increase the vehicle-guideway vibrations and rate of load reduction of the driving tyre.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.110-115
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• 2002

In this paper, the results of an analysis of the dynamic behavior of the eddy current brake(ECB) system are presented. The measured irregularity of the track in Korean high speed line and the track irregularity given by ERRI(high level) were used for simulation. The wheel-rail profile combination were analyzed with different rail gauges. A model of the bogie with an substitute body for the carbody was implemented in the Multi-body-Simulation Program SIMPACK. The ECB frame was modelled both as flexible body and as rigid body. Four different driving conditions were analyzed. In this study dynamic behavior in general were performed to evaluate the design of eddy current brake system and specially the effect of damper was also studied. A comparison of simulations with and without damper shows that the damper have most effect for lower speed. The simulation results will be verified by comparison with measured data from on line test and also used for improving design.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.429-436
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• 1998

In this paper, we derive the algorithm for calculating contact point between wheel and rail and develop the method for track modeling. The proposed methods use travelling distance to represent track center line poistion vector and track orientation with respect to Newtonian reference frame. The proposed methods can be easily used in multibody dynamic analysis. Two numerical examples are given to verify the validity of the proposed methods.