• Proceedings of the KSR Conference
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• 2010.06a
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• pp.64-71
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• 2010

It is suggested that the service life of the continuous welded rail(CWR) is estimated by the relationship between the rail surface irregularity according to the accumulated passing tonnage and bending fatigue of welded part in CWR. In this study, based on the results of bending fatigue tests of rail and results of measuring tests in situ of rail bending stress, this study estimated the bending fatigue life of welded rail in concrete track, adopting a Haibach's rule. The bending fatigue life of CWR considered the rail surface irregularity, train speed and the S-N curve by types of rail welding. In addition, this study estimated it for the fracture probability 1%, 0.1%, 0.01%. Therefore, this study proposed bending fatigue life of CWR in concrete track.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1243-1244
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• 2010

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.201-207
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• 2010

The replacement criterion of rail by accumulated passing tonnage was estimated by the bending fatigue life of rail. In order to estimate the bending fatigue life, it is basically needed to analyze bending fatigue behavior on the rail. In this study, the bending fatigue test were performed for 50kg/m and 60kg/m rails, and test specimens were distinguished by new and used rails and by the types of welded rail such as base material, thermite weld, and gas pressure weld. Also, this study analyzed the fractured surface, the position of initial crack and the bending fatigue behavior (S-N curve). Therefore, it evaluated S-N curve for welded rails according to the fracture probability. The result from this study might be used essential data in order to estimate the bending fatigue life of rail by the accumulated passing tonnage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.5
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• pp.1191-1198
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• 2015

In this study, vehicle/track interaction analysis by the Saemaul powered vehicle was carried out. The prediction equation for the bending stress of rail was estimated using the rail bending stress by the rail surface irregularities at welds. Also, the fatigue analysis using a S-N curve of welds in the conventional railway was carried out. We estimated the fatigue life of CWR by the fracture probability. By the rail grinding, the fatigue life of CWR was evaluated in consideration to reduce the rail bending stress through removing the rail surface irregularities. Therefore, it presented the fatigue life of CWR according to the rail grinding execution plan in the conventional railway.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.577-582
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• 2010

The importance of maintenance of rail surface defects is increasing according to the KTX operation. That is because during high speed operation of rolling stocks, rail surface defects shorten fatigue life of rail, accelerate track degradation and deteriorate ride comfort. Rail grinding has been applied for effective rail maintenance in Kyeong-Bu HS line. This paper evaluates the effectiveness of rail grinding in term of rail fatigue life. To this end, the stresses of the rail are measured under KTX running and the equivalent stress range is calculated by RMC after the frequency analysis done with rainflow counting method. Also, The Modified Miner's rule is applied to predict the fatigue life of ground rail. The result of the analysis shows that the fatigue life of ground rail is increased by 15%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.821-831
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• 2013

As a result of recent research, it is reported that the periodic replacements criterion of rails is able to extend as grinding rail surface and using the continuous welded rail (CWR). In this study, we carried out fatigue tests on existing laid rails. Based on the test results, an S-N curve expressing the remaining life of laid rails at a fracture probability of 50% was obtained using weighted probit analysis suitable for small-sample fatigue data sets. As rails used for testing had different histories in terms of accumulated tonnage, the test data were corrected to average out the accumulated tonnage. We estimated the remaining service lives for laid rails on the urban railway using equations developed in the past to estimate rail base bending stress and that surface irregularities into consideration. Therefore, estimating the remaining service life of laid rails showed that the rail replacement period could be extended over 200 MGT, although it is necessary to remove longitudinal rail surface irregularities at welds by grinding. Also, the fatigue test results under fatigue limit, Haibach's rule appling half slope of S-N curve under the fatigue limit was considered more reasonable than modified Miner's rule for estimating rail fatigue life.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1416-1422
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• 2010

Monorail has been classified as straddled type and suspended type. However, Inchon Wolmi Eunha rail, a center guide type first ever introduced in the world, uses a new concept Y-Beam as guide rail. Since Y-Beam takes horizontal loads of monorail through guide wheels, it is an essential structure for the safe operation along with concrete surface and steel beam which take vertical loads through main tires. This study presents the characteristic and reliability of Y-Beam and Y-Beam fixture, clamp, which are not only taking horizontal loads but also guarantying both guiding and stability of monorail and holding power supply line.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.735-740
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• 2005

In this paper, we designed a wedge type rail-clamp which can protect container crane from sudden wind blast with constant clamping force regardless of the operating period. When we design wedge type rail clamp, it is important to determine an angle of wedge which prevent rotating of jaw and for smooth operation when wind blows. Therefore, this paper suggest a process to decide an angle of wedge within proper range obtained by experimental analysis as well as FEA of the wedge type rail clamp. A model with $6^{\circ}$ wedge angle is the most proper model to use in rail clamp bemuse it generated satisfactory clamping force and rotating angle underdesign specification.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.62-64
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• 2000

레이다 빔 스케쥴러는 레이타의 전체적인 운용과 제어를 담당하는 레이다 통제기의 핵심기능으로서 레이다의 운용시간 및 송신 전력 등 한정된 가용 자원을 효율적으로 관리하기 위한 최적화 기법이 매우 중요하다. 본 논문은 충남대에서 개발한 실시간 운용체제인 iRTOS를 기반으로 하여 방위각 방향은 기계적 회전을 하고 고각 방향은 위상을 가변하여 다수의 위협 표적을 실시간으로 탐지하고 추적하는 회전형 3차원 위상배열 레이다에 적용 가능한 레이다 빔 스케쥴러의 구현 알고리즘에 관한 내용이다. 제안된 레이다 빔 스케쥴러는 우선 순위를 갖는 핵심적인 스케쥴링 태스크와 이를 보조하기 위한 다수의 기능 태스크를 정의하고 생성하였으며 태스크간 데이터 교환을 위하여 인터럽트 처리, 시간 관리, 세마포어 및 메시지 큐 등을 적용하였다. 레이다 빔 스케쥴러의 성능을 검증하기 위하여 다수의 모의 표적을 발생시켜 빔 스케쥴러의 상태와 성능을 확인하였으며, 자체 개발한 실시간 운용체제인 iRTOS를 이용하여 3차원 레이다 빔 스케쥴러를 구현할 수 있음을 확인하였다.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.72-77
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• 2009

지상 SAR 시스템은 산사태, 지반침하, 댐이나 대규모 지상시설의 변위 등에 대한 정밀 모니터링을 위한 기술로 주목받고 있다. 본 연구에서는 원형레일 기반의 지상 SAR 시스템에 대한 Forward Modeling S/W를 개발하였다. 이는 기존의 선형 레일을 이용하는 지상 SAR 시스템의 응용성 확대를 위해 원형레일 기반의 지상 SAR 시스템을 개발하고자 하는 연구의 일환으로서, 안테나를 원형 레일을 따라 움직이며 얻어지는 경우의 지상 SAR 자료획득 체계 설계와 영상화 처리 알고리즘의 개발 및 검증에 활용하기 위한 것이다. 여러 개의 point scatters를 대상으로 선형 레일을 따라 움직이는 안테나에 대한 시뮬레이션을 통해 얻어진 SAR raw signal 자료에 대하여 기존의 SAR 영상화 처리 알고리즘을 적용한 결과, 정확한 영상이 얻어지고 있음을 확인하였다.