• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.11-18
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• 2011

This paper proposed a new 2-D multi-body dynamic modeling technique to analyze overriding behaviors taking place during train collision. This dynamic model is composed of nonlinear springs, dampers and masses by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model for rollingstock, energy absorbing capacities of collision elements, accelerations of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we chose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3-D finite element analysis, and established a 2-D multi-body dynamic model. This 2-D dynamic model was simulated under the train-to-train collision scenarios, and evaluated with 3-D virtual testing model. It was founded from the simulation results that this 2-D dynamic model could well predict overriding behaviors, and the modeling technique of carbody deformation was very important in overriding estimation.

• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.28-34
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• 2014

In this paper, a concept design of a rail type ultra-high-speed train is proposed and its dynamic characteristics are analyzed. Instead of the existing solid axle, a new type bogie system and independently rotating wheels are applied in the proposed train. In order to analyze the dynamic characteristics, a multibody dynamic model of a vehicle is developed and the basic validity is verified by eigenvalue analysis. Also, it is shown that the critical speed is improved in comparison to that of existing high-speed train model HEMU-430X. Finally, through 7000R curved track driving analysis at a speed of 550 km/h, the lateral force of the wheels and the derailment quotient are estimated and the applicability of the new concept railway vehicle is confirmed.

• Journal of the Korean Society for Railway
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• v.2 no.3
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• pp.9-17
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• 1999

This paper presents a new algorithm to determine the pre-loads that sustain the static equilibrium state in a given position. The algorithm which uses a partial velocity matrix leads to an unconstrained optimization problem to compute the pre-loads of the suspensions. To demonstrate the validity of the proposed algorithm, the static analysis results that employ the pre-loads of three examples are presented using a reliable commercial program. Results of the analysis confirm the validity of the proposed algorithm.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.792-797
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• 2006

In general, the Maglev vehicle is ran over the elevated guideway consisted of steel or concrete structure. Since the running behaviour of the vehicle is affected by the flexibility of the guideway, the consideration of the flexibility of guideway is needed for evaluation of dynamics of both the vehicle and guideway. A new technique based on flexible multibody dynamics is proposed to model the Maglev vehicle, levitation controller, and guideway into a coupled model. To verify the technique, an urban Maglev vehicle is analyzed using the technique and discussions are carried out.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.139-146
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• 2010

In this study, a new equivalent modeling technique of rollingstock for 1-D collision dynamics was proposed using crash analysis of 3-D finite element model in some detail. To obtain good simulation results of 1-D dynamic model, the force-deformation curves of crushable structures should be well modelled with crash analysis of 3-D finite element model. Up to now, the force-deformation curves of the crushable structures have been extracted from crash analyses of sectionally partitioned parts of the carbody, and integrated into 1-D dynamic model. However, the results of the 1-D model were not satisfactory in terms of crash accelerations. To improve this problem, the force-deformation curves of the crushable structures were extracted from collision analysis of a simplified train consist in this study. A comparative study applying the suggested technique shows in good agreements in simulation results between two models for KHST.

• Journal of KSNVE
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• v.10 no.1
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• pp.117-122
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• 2000

The dynamics of train has recently been analysed in many cases and very complex nonlinear creep theories have been developed by many engineers. But much calculation time is spent and latest complex creep theories cannot be adapted in train analysis. In this study efficient and fast train analysis method was suggested. Many of degree of freedom were reduced in multi-vehicle system using equivalent system and fast calculation time was achieved. And the accuracy of equivalent system method was proved by linear and nonlinear dynamic analysis.

• Journal of the Korean Society for Railway
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• v.2 no.1
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• pp.47-55
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• 1999

In this paper, an efficient and accurate formulation for the transient analysis of constrained multibody systems is presented. The formulation employs Kane's method along with the null space method. Kane's method reduces the dimension of equations of motion by using partial velocity matrix: it can improve the efficiency of the formulation. Furthermore, the formulation partitions the coefficient matrix of linear and nonlinear equations into several sub-matrices using kinematic uncoupling. This can solve the equations more efficiently. The proposed formulation can be used to perform dynamic analysis of systems which can be partitioned into several sub-systems such as train systems. One numerical example is given to demonstrate the efficiency and accuracy of the formulation, and another numerical example is given to show its application to the train systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.81-87
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• 2017

This paper describes the dynamic behavior and enhancement of Korean high-speed trains. The tail vibration reduction method of the yaw damper installation method change, which was derived from previous research, was applied to the running test of high-speed train. In addition, the vibration reduction method for the entire vehicle was derived by a numerical method and its effect was confirmed by a running test. The improved design was applied to the double-deck high-speed train coaches and the commissioning proceeded without problems in dynamic behavior. Sensitivity analysis of the suspension parameters affecting the critical speed of Korean next-generation high-speed trains was performed and four design variables that greatly affected the critical speed were derived. These were in the order of the primary elastic joint x-directional stiffness, the secondary yaw damper series stiffness, the secondary lateral damper damping coefficient, and the carbody damper damping coefficient. By optimizing the design variables, the suspension parameter that improves the critical speed by 23.3% can be used in the commercial designs of Korean next-generation high-speed trains.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.581-587
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• 2013

In a magnetic train set composed of more than two cars, the installation of dampers between cars is carefully considered for improving both the ride quality and the safety, particularly during curve negotiation. In this study, a dynamic simulation of the ride quality and curve negotiation of a Maglev vehicle was carried out. The dynamic model is developed based on multibody dynamics. The presented full vehicle multibody dynamic model integrates the electromagnet model and its control algorithm. By using this model, the effects of the dampers are numerically analyzed. The proposed damper is installed on the vehicle and tested to analyze its effects. In this study, the simulation and measured results of the vehicle behavior and ride quality are discussed.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.343-351
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• 2012

With the cooperation of many research institutes and railway companies, the next generation high speed train is under development for many years. To confirm the safety requirement of the developed high speed train, multibody dynamic analysis is implemented. Through this analysis, railway derailment and lateral guiding force simulation was evaluated according to UIC code 518 OR for international railway vehicle. Test results were compared by limit value of safety criteria. Safety evaluation results, according to international standards, would provide basic reference data of ensuring safety speed and track radius curve. The safety of the train at the maximum speed is verified by numerical analysis results.