• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.9 s.240
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• pp.1183-1190
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• 2005

This paper presents a dynamic model of railway vehicle for the development of a 6-axis tilting train simulator. The tilting train simulator will be used to verify the tilting electronics and tilting control algorithm that are to be applied to the Korean tilting train. The tilting train simulator is composed of 6 electric-driven actuators, a track generation system, a graphic user interface, and a visualization system with a 1600mm-diameter dome screen. The each system shares the data by means of ethernet network in realtime. In this study, a train model of 9-DOF with a force generation system to tilt train body has been developed. The dynamic analysis for the straight track running and curve negotiation of a railway vehicle can be performed in the model. In this study, a verification study for the application of the model to the simulator has been conducted under curving situation on the track with different radii.

• Journal of the Korea Furniture Society
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• v.23 no.4
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• pp.467-478
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• 2012

Interurban railway is expanded by transportation that population can be centralism and cope efficiently in traffic jam by augmentation of vehicles in the city. Railroad chair departs in space of an existent simple rest and products that can raise human body standard and size by powerful engineering vicinity, quality of the material, psychological satisfaction etc. of users are developed steadily. Specially, study of space that can use various materials efficiently with bodily size government official because various of man and woman old and the young etc.. are using in occasion of the train is urgently required. Specially, railroad chair is a product that material and standard, structure, human body engineering, a finish etc. is studied variously. In the case of advanced nation, in case of design a chair operating time of railroad, is placed as all standards orderly and harmonious because is considered exercise dynamics etc.. and designs. The other side, in the case of our country, study expert of chair is short real and is depending on technological data of overseas railway vehicle. Chair for railroad must consider removal of short-range, long distance. That have to be consider to a lot of uncomfortable such as psychological satisfaction of user because the domestic Motor Companies are defining in fair development study and many researchers but the railroad chair company are not accumulated professional manpower and technological know-how. Railway vehicle can recognize that overseas visitors as well as native is important element as space that space is exposed internationally by product that Public personality which used cultural value is strong. Therefore, wish to plan valid spec relationship presentation of various design and specification, function etc.. and contribute to railroad chair development design process lists and analyzes van instances of railway vehicle chair of inside and outside of the country through this study.

• International Journal of Railway
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• v.4 no.4
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• pp.97-102
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• 2011

In an EMS (Electromagnetic suspension)-type Maglev (Magnetically-levitated) vehicle, the flexibility of the bogie frame may affect the acceleration of the electromagnet that is input into the control system, which could lead to instability in some cases. For this reason, it is desirable to consider bogie frame flexibility in air gap simulations, for the optimization of bogie structure. The objective of this paper is to develop a flexible multibody dynamic model of 1/2 of an EMS-type Maglev vehicle that is under testing, and to compare the air gap responses obtained from the rigid and the flexible body model. The feedback control system and electromagnet models that are unique to the EMS-type maglev vehicle must be included in the model. With this model, dynamics simulations are carried out to predict the air gap responses from the two models, of the rigid and flexible model, and the air gaps are compared. Such a comparative study could be useful in the prediction of the air gap in the design stage, and in designing an air gap control system.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.51-57
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• 2010

The aerodynamic drag of ultra high-speed train in evacuated tube have been calculated using computational fluid dynamics and the variation of aerodynamic drag for the change of major system parameter of tube-vehicle system such as the train speed, air density, and the tunnel diameter. The aerodynamic drag in the tube increases with increasing train speed, however, the ratio of drag increase in tube is larger than that on the open field, the V square rule. The aerodynamic drag decreases with increasing tunnel diameter and increasing air density, and the drag increasing for air density is almost linear just like that on open field. For some combination of the parameters, the trend of aerodynamic drag of train showed irregularity.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.927-939
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• 2007

This paper concerns dynamics of a wheel-axle set on a tangent track which was already published in a book titled "Dynamics of Railway Vehicle Systems" authored by Garg and Dukkipati [1], pointing out several missing terms and erroneous parts in the derived expressions on the conventional governing equations of motion. It is indicated that the x-direction components of normal forces at left and right wheel-rail contact points in the equilibrium axis were missed. Another point is that in deriving the creepages the disturbed velocity components in both x and y directions in the equilibrium axis should not be disregarded in the first term of the numerators. When considering the creepage in the y direction in the body coordinate system, the second term of lateral velocity at the contact point also cannot be neglected. Besides, the hyper-assumptions in the final expressions of vertical components of normal forces at left and right wheel-rail contact points have been recovered in reaching the final stage of analytical model development. Finally it is noteworthy that the process of applying creep theory is deemed to contain a little bit inconsistencies and ambiguities to be clear.

• Journal of the Korean Society for Railway
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• v.6 no.2
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• pp.122-128
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• 2003

The acceptance test of KTX has been performed in Korea. During the test, lateral vibration of carbody over the accepted value called sway was found. Many activities have been taken to find the cause of the vibration and the counter-measure. KTX has 20 car trainset formation whose trailer cars are linked by articulate bogies. So this study is performed to see the effects of long trainset formation on vehicle dynamics and the train stability by 16 car vehicle model. Firstly the reliable vehicle model which shows well the tendencies appeared in the tests on the high speed test line is required to find the cause of lateral vibration and the countermeasure. Vehicle model was made for the analysis with VAMPIRE. The analysis results show that secondary air spring lateral stiffness is the most significant parameter to cause carbody lateral vibration. Mode analysis results show that the least damped mode shape is similar to the vibration pattern shown in the tests that the amplitude of the motion increases along the train set and decreases in the tail part. The lateral vibration was "appeared at the speed range between 100km/h and 200km/h and disappeared at the low speed and the high speed.

• Journal of the Korean Society for Railway
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• v.4 no.4
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• pp.131-137
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• 2001

The dynamic behavior of high speed train is very important because of its safety and passengers' ride comfort. The railway vehicle is composed of many suspension components, such as 1st springs, 1st dampers, 2nd springs and 2nd dampers, that have an influence on the dynamic characteristics of high speed train. Also, the wheel/rail shapes and the track geometry affect the dynamic behavior of high speed train. This paper reviews the dynamic behavior of KHST in the KTX test line. The VAMPIRE program is used for this simulation. The simulation results are within the limits of safety criteria. Thus the KHST can operate safely at 350 km/h in the KTX test line.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.421-428
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• 1998

Sensitivity analysis of suspension elements of an articulated bogie for light railway vehicles is presented. The ride, stability and safety are used as dynamic performance index. Suspension elements of 10 and a conicity of wheel are used as design variables, To analyze sensitivity of design variables, the railway vehicle dynamics analysis program AGEM is used. The results shows that the secondary suspension elements have a strong effect on ride and the primary suspension elements have a moderate effect on ride. Conicity of wheel has a strong effect on the stability, The safety is not effected by all the design variables.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.4
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• pp.64-71
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• 2002

Recently, mechanical systems such as a high-speed vehicles and railway trains moving on flexible beam structures have become a very important issue to consider. Using the general approach proposed in the first part of this paper, it is possible to predict motion of the constrained mechanical system and the elastic structure, with various kinds of foundation supporting conditions. Combined differential-algebraic equation of motion derived from both multibody dynamics theory and finite element method can be analyzed numerically using a generalized coordinate partitioning algorithm. To verify the validity of this approach, results from the simply supported elastic beam subjected to a moving load are compared with the exact solution from a reference. Finally, parametric study is conducted for a moving vehicle model on a simply supported 3-span bridge.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.715-720
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• 2002

The dynamic load effects, generated by moving trains, are transferred to the railway bridges through tracks. The dynamic load effects may vary due to the dynamic characteristics of the applied vehicle loads and the railway bridges including the track system. However, the track models have been neglected or simplified by spring elements in the most studies since it is quite complicated to consider the track systems in the dynamic analysis models of railway bridges. In this study track system on railway bridges are modeled using a three-dimensional discrete-support model that can simulate the load carrying behavior of tracks. A 40m simply supported prestressed concrete box-girder system adopted for high-speed railway bridges are modeled for simulation works. The train models are composed of 20 cars for KTX. The dynamic response of railway bridges are found to be affected depending on whether the track model is considered for not. The influencing rate depends on the traveling speed and different wheel-axle distance. The dynamic bridge response decreases remarkably by the track systems around the resonant frequency. Therefore, the resonance effect can be reduced by modifying the track properties in the railway bridge, especially for KTX trains.