• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1123-1128
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• 2011

Generally, there are many types of data, such as wear data or irregularity data, are detected for analyzing railway performance. The analysis of railroad wear or irregularity data is most effective method for the efficient railway maintenance. Especially, the track damaged directly by train, have as important position with the inspection data. This study suggest the Life-Cycle performance analysis method and process of railroad by analyzing two types of data, wear data and irregularity data. This analysis methods can be applied to suggest the Life-Cycle performance of railroad based on environmental factors or design factors, such as sleeper type, roadbed type, cant, the radius of curvature, speed, maintenance history and so on.

• Structural Engineering and Mechanics
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• v.48 no.1
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• pp.93-102
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• 2013

An optimization work was developed in this work to provide design information for sandwich beam in civil engineering applications. This research is motivated by the wide-range applications of sandwich structures such as; slab, beam, girder, and railway sleeper. The design of a sandwich beam was conducted by using analytical and numerical optimization. Both analytical and numerical procedures consider the optimum design with structure mass objective minimization. Allowable deflection was considered as design constraints. It was found that the optimized core to the skins mass ratio is affected by the skin to core density and elastic modulus ratios. Finally, the optimum core to skin mass ratio cannot be constant for different skin and core materials.

• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.89-94
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• 2016

The objective of this study was to estimate the dynamic behavior of a personal rapid transit(PRT) track system using a rail of rectangular tube section and a rail joint of sliding type, and to compare the results with the normal rail and rail joint of a PRT track system by performing field measurements using actual vehicles running along the service lines. The measured vertical displacement of rail and sleeper, and vertical acceleration of rail for the normal rail and rail joint section were found to be similar, and the rail joint of sliding type satisfied the design specifications of the track impact factor for a conventional railway track. The experimental results showed that the overall dynamic response of the rail joint were found to be similar to or less than that of the normal rail, therefore the rail joint of sliding type for PRT track system was sufficient to ensure a stability and safety of PRT track system.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.346-353
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• 2005

Track substructure(ballast, subgrade) should have sufficient strength and adequate stiffness to fully support track superstructure(rail, fastener, sleeper). Vertical support stiffness of track comes from the sufficient thickness, adequate strength and stiffness of material of substructure layers. Since the vertical support stiffness of track substructure is closely related with the track geometry, the evaluation of the stiffness is very important to understand the track states. This paper introduces the system, which are composed of Ground Penetrating Radar(GPR), Portable Ballast Sampler(PBS), and Light Falling Weight Deflectometer(LFWD), to evaluate substructure condition and summarizes the field test results performed with the reliable system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.829-835
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• 2001

The sources of wayside noise for the high speed train are the aerodynamic noise, rolling noise and power unit noise. One of the best ways to control the wayside noise is to analysis the noise level. In this paper, we measure the wayside noise and the vibration of the rail/sleeper for Korean Train Express (KTX) and compare with the results for the conventional train. The measurement results for KTX show that the characteristics of the noise and vibration are different from the conventional train and the rolling noise and power unit noise are the major sources.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.395-403
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• 2007

Railroad track consists of relatively simple structures such as rail, sleeper, ballast. Roadbed shares vertical pressure by train load which passed through rail to ballast as base that supports the track. For evaluating stress and displacement of roadbed due to the railroad load is an important role on the track as a basic data for estimation of the durability and design of the roadbed thickness. GEOTRACK program applied multi-layered theory was developed for analyzing railroad track structure. GEOTRACK program is a sort of numerical analysis program which has advantage that can analysis component of track by simple method. In this study, this program was used to preform the numerical analysis by changing track conditions and roadbed conditions such as tie, reinforced roadbed, dynamic wheel load, Resilient modulus and so on. Further detail will be presented on the paper.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2007.11a
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• pp.153-161
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• 2007

견관절의 ABER position에서 posterosuperior rotator cuff 가 posterior glenoid에 contact 하여 internal impingement가 일어나는 현상은 운동선수가 아닌 일반인에게도 발생하는 physiologic phenomenon이며 과도한 반복 동작으로 인하여 증상이 발현한다. Internal impingement는 증상이 모호할 뿐만 아니라 견관절 내 여러 병소가 함께 존재하기 때문에 각각의 pathology에 대한 자세하고 정확한 evaluation이 필수적이다. 아직 controversy가 있지만 internal impingement의 pathologic factors로서는 anterior capsular laxity (true anterior laxity), posteroinferior capsular tightness (pseudo anterior laxity)와 이로 인한 glenohumeral internal rotation deficit (GIRD), 그리고 SICK scapula syndrome (scapular dyskinesis) 등으로 요약할 수 있다. 진단은 주로 병력 청취와 신체 검사로 내려지며 ultrasonogram, MRA등으로 확진한다. Sleeper stretching exercise 등과 같은 보존적 치료에 반응이 좋지만 6개월간의 재활 치료에도 호전이 없다면 증상과 직접 관련된 주 병소(appropriate pathology)를 찾아 이에 대한 적절한 수술이 이루어져야 한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.1
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• pp.56-62
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• 2003

The major noise source for the conventional train is the rolling noise caused by the interaction of the wheels and rails during the train passage on the tangent track. In order to control the rolling noise, the noise radiated from wheels, rails and sleepers should be analyzed and predicted. In this paper, a prediction method of wheel/rail rolling noise generated by the roughness of the wheel/rail surface is described, where the method is considering the effect of noise radiated by sleepers and the effect of ground. The method is applied to the Korean railway system, and the sound pressure level (SPL) predicted by the proposed method is compared with the measured SPL. Overall. the result shows good agreement between the predicted and measured values.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.9
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• pp.668-673
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• 2002

The sources of wayside noise for the high -speed train are the aerodynamic noise, rolling noise and power unit noise. We should know the major source to control noise radiated from train. In this paper, we present the test results on the wayside noise and the vibration of the rail/sleeper during the passing of Korean Train Express (KTX). It turns out that the major noise sources for KTX are the rolling noise and power unit noise at 300 km/h. Generally, the noise attenuation with distance is independent of train speed. However, the test results show that in the near field the noise levels decrease by about 5~6 ㏈(A) per doubling of distance at speed in the range of 50~120 km/h and about 3~4 ㏈(A)/d.d at 300 km/h.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1010-1015
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• 2009

Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.