• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.169-173
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• 2006

The major objective of this study is to investigate the fatigue life evaluation of immovability crossing for railway turnout by the field test. In railway engineering, an appliance is necessary to allow a vehicle to move from one track to another. This appliance came to be known technically as turnout. So, turnout is required very complex railway technologies such as rolling stock, track. Due to the plan under the application of high speed train, turnout are needed more stable far fatigue behaviors. It analyzed the mechanical behaviors of turnout crossing with propose its advanced technical type on the field test and fatigue evaluation far the dynamic fatigue characteristics. As a result, the advanced type crossing are obviously effective for the fatigue damage ratio and dynamic response which is non-modified type. The analytical and experimental study are carried out to investigate the passing path of contact surface and fatigue damage trend decrease dynamic stresses and deflections on advanced crossing type, And the advanced type reduce dynamic fatigue damage ratio and increase fatigue life(about each 38%) more than non-modified type. From the field test results of the servicing turnout crossing, it is evaluated that the modification of contact angle, weight, material and sectional properties is very effective fur ensure against fatigue risks.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.589-594
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• 2004

In design of suspension system for KHST, it was applied the approximated optimization method using meta-models which called Response Surface Model and Neural Network Model for 29 design variables and 46 performance index. These models was coded using correlation between design variables and performance indices that is made by the 66 times iterative execution through the design of experimental table consisted orthogonal array L32 and D-Optimal design table. The results show that the optimization process is very efficient and simply applicable for complex mechanical system such as railway vehicle system. Also it was compared with the sensitivity of some design variables in order to know the characteristics of two models. This paper describes the general method for dynamic analysis and design process of railway vehicle system applied to KHST development, and proposed the efficient methods for vibration mode analysis process dealing with test data and the function based approximation method using meta-model applicable for a complex mechanical system. This method will be able to apply to the other railway vehicle system in oder to systematize and generalize the design process of railway vehicle dynamic system.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1-11
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• 2006

To be design the slope, the area distributed the shale or mica schist which was metamorphosed by shale must carefully consider the stability. The shale has the detrital materials of which the grain size are 1/256mm and fissility. As the reason the slope of shale is always unstable by bedding slip and fissility but also the joint and fault. Mica schist is also another unstable rock for slope by schistosity, cleavage, axial plane of a fold etc. In general shale and mica schist contain the swelling clay minerals such as smectite, vermiculite and montmorillonite. These minerals make the slope unstable. At OO tunnel construction area for the rail way of the Kyungbu high speed train, the slope of mica schist is very unstable by the distribution phenomena of the discontinuous plane such as joints which are 1-5cm spacing and thrust and strike-slip fault. By the drilling core of this area, most RQD have 0-20%.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.158-162
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• 2004

The magnetic levitator is the device which can float a magnetic material at the midair by electromagnetic force and it's principle can be applied to the high speed magnetic bearing or magnetic levitation train. There are many difficulties to control, because the magnetic levitator is basically a nonlinear and unstable system. In this paper, this system is modeled assuming that it is a linear system nearby an operating point, and a proportional and derivative(PD) position controller is designed to carry out the variable position control. The performance of position control response is shown through simulation and experiment. A prototype magnetic levitator is constructed using PWM converter and DSP(Digital Signal Processor) based control board.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.572-577
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• 2011

Curve squealing of inter-city railway vehicle is a noise with high acoustic pressure and rather narrow frequency spectra. This noise turns out to be very annoying for the people living in the neighborhood of locations and the passenger in railway vehicle where this phenomenon occurs. Squealing is caused by a self-exited stick-slip oscillation in the wheel-rail contact. Curve squeal noise of railway vehicles that passed by a factor of the speed limit, so to overcome in order to improve running performance is one of the largest technology. In the present paper, characteristic of squeal noise behavior at the Hanvit-200 tilting train test-site. Curve squealing of railway wheels/rail contact occurs in R400~ R800 curves with a frequency range of about 4~11 kHz. If the curve is less than the radius of wheel frail contact due to |left-right| noise level difference (dBA) shows a significant effect of squeal noise were more likely.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.90-98
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• 2005

HMT is a type of continuously variable transmission which has split power flow path characteristics with gear train and hydro static unit. The benefit of improved fuel economy and high power capacity enables it to be a promising application fur large vehicles. This paper presents the analysis results including velocity, static torque, transmission efficiency and dynamic model of the HMT that is developed for city buses. The speeds or gear shafts, the static clutch torque and split power ratio for each mode are detailed here. From the analysis of HMT transmission efficiency considering the power loss in meshed gear and hydraulic unit, we can conclude that minimization of hydraulic power is necessary for improved fuel economy design. Also, the dynamic simulation result for mode shift characteristics shows that little shift shock is observed because of the synchronized rotation speed in clutch.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.38-42
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• 2004

The optimal design for a leading car considering the aerodynamic resistance is required on the high-speed train due to increasing of ratio of drag force with proportion for the square of velocity. The aerodynamic analysis using CFD in the stage of concept design offers more economical analysis method which is used to estimate the influence of flow and pressure around the leading car than the experimental method using the Mock-up. In this study, we want to assist the artistic design with aerodynamics analysis in order to get the optimal design for leading car made of composite material. The results of aerodynamic analysis for two leading car models, which one is expressed with lineal beauty and the other is with curvaceous beauty, are compared with each other and offer the proposal of modification for two models in order to decrease be drag force. The shape of curvaceous model is better for the pressure force but slightly worse for the viscous force than the other. The Fluent software is used for the calculation of flow profile in this study.

• Journal of the Korean Society for Railway
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• v.14 no.6
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• pp.562-568
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• 2011

Superimposition of horizontal and vertical curves occurs frequently owing to geographical conditions. It may hamper train ride comfort and running safety and inflate maintenance costs. In this study, when the horizontal and vertical curves are superimposed, in order to analyze the effects of the compensation cant, the analytical study for running safety, ride comfort and track forces was performed in high speed line. From the analysis results, it was found that it is better to apply the compensation cant at superimposition part.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.674-679
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• 2016

According to the conventional studies on the noise and cardiovascular effect, railway noise is better associated with hypertension and adverse cardiovascular events than road traffic noise. But the underlying mechanisms remain unclear. We investigated the hypothesis that exposure to acute railway noise would the unfavorable effect of cardiovascular and autonomic system in healthy young subjects. Using a randomized, sham-controlled cross-over design, ten subjects were assigned to receive either an exposure to high speed train noise (84 dB) for 30 minutes or a control condition (non noise), separated by two days. Blood pressure, heart rate, augmentation index and heart rate variability as indices of cardiovascular and autonomic system function were measured at baseline, during, and recovery from two trials. The results show that exposure to acute railway noise significantly increased diastolic blood pressure and augmentation index, which may cause of adverse cardiovascular effects.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.176-184
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• 2000

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