• Title, Summary, Keyword: 철도차량 동역학

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Study on the Levitation Stability of Maglev Vehicle considering the Vibration of Steel Switch Track (강재 분기기의 진동을 고려한 자기부상열차 부상안정성 연구)

  • Han, Jong-Boo;Park, Jinwoo;Han, Hyung-Suk;Lee, Jong-Min;Kim, Sung-Soo
    • Journal of the Korean Society for Railway
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    • v.18 no.3
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    • pp.175-185
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    • 2015
  • Generally, in the train area, switch tracks have required high reliability because this system is directly associated with derailment. Especially, switch tracks of Maglev vehicles must be moved in terms of the whole geometric characteristics, in which the bogies are encased in the switch track. For this reason, switch track was constructed with steel lighter than concrete girders. But, the steel switch track was weak because of structural vibration as well as structural deformation. Therefore, it is important to predict the levitation stability when a vehicle passes over flexible switch track. The aims of this paper are to develop a coupled dynamic model to describe the relationship between a Maglev vehicle and switch track and to predict the levitation stability. In order to develop the coupled dynamic model, a three dimensional vehicle model was developed based on multibody dynamics; a switch model was made using the modal superposition method. And, the developed model was verified using comparison measured data.

A Study on Conceptual Design for Crashworthiness of the Next Generation High-speed EMU (동력분산형 차세대고속전철의 충돌안전도 개념설계 연구)

  • Kim, Geo-Young;Cho, Hyun-Jik;Koo, Jeong-Seo
    • Journal of the Korean Society for Railway
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    • v.11 no.3
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    • pp.300-310
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    • 2008
  • Through this study, a conceptual design for the next generation high-speed EMU has been derived to meet the crash worthiness requirements of the Korean rollingstock safety regulation. The crashworthiness regulations require some performance requirements for two heavy collision accident scenarios; a train-to-train collision at the relative speed of 36 km/h, and a collision against a standard deformable obstacle of 15 ton at 110km/h. The complete train set will be composed of 2TC-6M with 13 ton axle load, which is different from KTX with the power car of 17 ton axle load. Using theoretical and numerical analyses, a crashworthy conceptual design was derived in terms of mean crush forces and energy absorptions for principal crushable structures and devices. The derived conceptual design was evaluated and improved using one dimensional dynamic simulations for the bar-spring-damper-mass model. It is shown from the simulation results that the suggested conceptual design can easily satisfy domestic crashworthiness requirements.

Human Body Vibration Analysis under Consideration of Seat Dynamic Characteristics (시트 동특성을 고려한 인체 진동 해석)

  • Kang, Juseok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.12
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    • pp.5689-5695
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    • 2012
  • In this study, vibration properties of seat and human body are analyzed through test and numerical analysis methods by taking into account the viscoelastic characteristics of polyurethane foam as seat material which is applied for vehicle. These viscoelastic characteristics which show nonlinear and quasi-static behavior are obtained by compression test. In addition, the viscous elastic property of polyurethane foam is modelled mathematically by using convolution integral and nonlinear stiffness model. In order to analyze the performance on ride comfort of seat, vertical vibration model is established by using dynamic model of seat and vertical vibration model of human body at ISO5982, and so the related motion equations are derived. A numerical analysis simulation is applied by using the nonlinear motion equation with Runge-Kutta integral method. The dynamic responses of seat and human body on the input of vibration acceleration measured at the floor of the railway vehicle are examined. The variation of the index value at ride comfort on seat design parameters is analyzed and the methodology on seat design is suggested.

Investigation of Vehicle Dynamic Behavior of Composite Bogie Under Different Rubber Bushing Stiffness Values (고무부싱의 강성에 따른 복합소재 대차의 동적거동 평가)

  • Kim, Il Kyeom;Kim, Jung Seok;Lee, Woo Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.3
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    • pp.303-309
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    • 2015
  • In this study, a vehicle dynamic analysis and roller rig test were performed to evaluate the applicability of a suspensionless composite bogie to railway vehicles. A vehicle dynamic analysis was carried out under different rubber bushing stiffness values. The stiffness of the rubber bushing that plays a role in guiding wheel sets was varied in the range of 10-100 MN/m, in 10-MN/m steps. Based on the results, the composite bogie with a rubber bushing stiffness of more than 40 MN/m satisfied the design requirements. In addition, a rubber bushing with a stiffness of 81 MN/m was fabricated, and a roller rig test was performed. Based on the test results, the vehicle equipped with the composite bogie had a critical speed of 363 km/h, which agreed with the simulation result within an error of 10%.

Analysis of Dynamic Equilibrium Configuration of Speed Governor (조속기의 동적 평형위치 해석)

  • Kang, Juseok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.10
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    • pp.4733-4738
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    • 2013
  • This paper proposes a method to obtain the dynamic equilibrium configuration of a constrained mechanical system by using multibody dynamic analysis. Dynamic equilibrium equations with independent coordinates are derived from the time-dependent constraint equations and dynamic equations of a multibody system. The Newton-Raphson method is used to find numerical solutions for nonlinear algebraic equations that are composed of the dynamic equilibrium and constraint equations. The proposed method is applied to obtain the dynamic equilibrium configuration of a speed governor, and the results are verified on the basis of the results from conventional dynamic analysis. Furthermore, vertical displacements at equilibrium configuration, which varied with the rotational velocity of the speed governor, are calculated, and design parameter analysis of the equilibrium configuration is presented.

A Study on the Dynamic Characteristics of the Bi-modal Tram with All-Wheel-Steering System (전차륜 조향 장치를 장착한 굴절궤도 차량의 주행특성에 관한 연구)

  • Lee, Soo-Ho;Moon, Kyung-Ho;Jeon, Young-Ho;Lee, Jung-Shik;Kim, Duk-Gie;Park, Tae-Won
    • Journal of the Korean Society for Railway
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    • v.10 no.4
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    • pp.444-450
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    • 2007
  • The bi-modal tram guided by the magnetic guidance system has two car-bodies and three axles. Each axle of the vehicle has an independent suspension to lower the floor of the car and improve ride quality. The turning radius of the vehicle may increase as a consequence of the long wheel base. Therefore, the vehicle is equipped with the All-Wheel-Steering(AWS) system for safe driving on a curved road. Front and rear axles should be steered in opposite directions, which means a negative mode, to minimize the turning radius. On the other hand, they also should be steered in the same direction, which means a positive mode, for the stopping mode. Moreover, only the front axle is steered for stability of the vehicle upon high-speed driving. In summary, steering angles and directions of the each axle should be changed according to the driving environment and steering mode. This paper proposes an appropriate AWS control algorithm for stable driving of the bi-modal tram. Furthermore, a multi-body model of the vehicle is simulated to verify the suitability of the algorithm. This model can also analyze the different dynamic characteristics between 2WS and AWS.

Study of Influence of Wheel Unloading on Derailment Coefficient of Rolling Stock (철도차량의 윤중 감소가 탈선계수에 미치는 영향 연구)

  • Koo, Jeong Seo;Oh, Hyun Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.2
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    • pp.177-185
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    • 2013
  • A new theoretical derailment coefficient model of wheel-climb derailment is proposed to consider the influence of wheel unloading. The derailment coefficient model is based on the theoretical derailment model of a wheelset that was developed to predict the derailment induced by train collisions. Presently, in domestic derailment regulations, a derailment coefficient of 0.8 is allowable using Nadal's formula, which is for a flange angle of $60^{\circ}$ and a friction coefficient of 0.3. However, theoretical studies focusing on different flange angles to justify the derailment coefficient of 0.8 have not been conducted. Therefore, this study theoretically explains a derailment coefficient of 0.8 using the proposed derailment coefficient model. Furthermore, wheel unloading of up to 50% is accepted without a clear basis. Accordingly, the correlation between a wheel unloading of 50% and a derailment coefficient of 0.8 is confirmed by using the proposed derailment coefficient model. Finally, the validity of the proposed derailment coefficient model is demonstrated through dynamic simulations.

Optimization of Design Variables of Suspension for Train using Neural Network Model (신경회로망 모델을 이용한 철도 현가장치 설계변수 최적화)

  • 김영국;박찬경;황희수;박태원
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1086-1092
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    • 2002
  • Computer simulation is essential to design the suspension elements of railway vehicle. By computer simulation, engineers can assess the feasibility of a given design factors and change them to get a better design. But if one wishes to perform complex analysis on the simulation, such as railway vehicle dynamic, the computational time can become overwhelming. Therefore, many researchers have used a mega model that has a regression model made by sampling data through simulation. In this paper, the neural network is used a mega model that have twenty-nine design variables and forty-six responses. After this mega model is constructed, multi-objective optimal solutions are achieved by using the differential evolution. This paper shows that this optimization method using the neural network and the differential evolution is a very efficient tool to solve the complex optimization problem.

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Development of a Dynamic Simulation Program for Railway Vehicles (철도차량을 위한 동역학 해석 프로그램 개발)

  • Cho, Jae-Ik;Park, Tae-Won;Yoon, Ji-Won;Kim, Young-Guk
    • Proceedings of the KSR Conference
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    • pp.473-479
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    • 2009
  • Dynamic analysis is necessary for the High-Speed Railway vehicle which aims to run on max 400km/h. Especially, dynamic simulation using CAE(Computer Aided Engineering) can help to reduce the time of development of the High-Speed Railway vehicles. Also, it helps to reduce prices and improve the quality such as safety, stability and ride. There are many dynamic software for a railway vehicle, such as Vampire and ADAMS-Rail. There are limitations for each software and difficulties to analyze overall dynamics for entire railway system. To overcome these limitations, in this study, a program which can simulate entire railway vehicles was developed. This program is easy to use because it was developed using C++, which is object-oriented programming language. In addition, the basic platform for the development of dynamic solver is prepared using the nodal, modal coordinate system with a wheel-rail contact module. Rigid, flexible and large deformable body systems can be modeled by a user according to the characteristic of a desired system. Its reliability is verified by comparison with a commercial analysis program.

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Optimization of Design Variables of a Train Suspension Using Neural Network Model (신경회로망 모델을 이용한 철도 현가장치 설계변수 최적화)

  • 김영국;박찬경;황희수;박태원
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.7
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    • pp.542-549
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    • 2002
  • Computer simulation is essential to design the suspension elements of railway vehicle. By computer simulation, engineers can assess the feasibility of given design variables and chance them to get a bettor design. Even though commercial simulation codes are used, the computational time and cost remains non-trivial. Therefore, malty researchers have used a mesa model made by sampling data through simulation. In this paper, four mesa-models for each index group such as ride comfort, derailment Quotient, unloading radio and stability index, are constructed by use of neural network. After these meta models are constructed, multi-objective optimization are achieved by using the differential evolution. This paper shows that the optimization of design variables using the neural network model is very efficient to solve the complex optimization Problem.