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서정원(J. W. Seo),권성태(S. T. Kwon),권석진(S. J. Kwon),이동형(D. H. Lee) 한국도시철도학회 2014 한국도시철도학회논문집 Vol.2 No.2
Rolling contact fatigue and wear of rails are inevitable problems for railway system due to wheel and rail contact. On straight track, the wheel tread is in contact with the rail head. However, In curves, especially, large sliding on the contact patch occurs at the wheel tread and flange. Due to this sliding, wear increases in the wheel/rail contact under the dry condition. In order to develop new materials and predict wear. It is important to understand the wear mechanism in rail steels. In this study, we have investigated wear characteriscs of rail steel using twin disc testing.
김대진(D. J. Kim),석창성(C. S. Seok),구재민(J. M. Koo),박재실(J. S. Park),서정원(J. W. Seo),구병춘(B. C. Goo) 한국철도학회 2004 한국철도학회 학술발표대회논문집 Vol.- No.-
Under cyclic loading, the fatigue failures of welded joints occur at weld toes which induce stress concentration by weld shape. So we need to obtain the peak stress and the S-N curve to assess the fatigue strength of welded joints. However the measurement of peak stress is of high uncertainty and low reproducibility, so we use nominal stress instead in fatigue tests of welded joints. In this study, fatigue tests to obtain S-N curves am FE analyses to obtain stress concentration factors were conducted for the two types of cruciform fillet welded joints, that is, load-carrying and non load-carrying types. Then we changed the obtained S-N curves to that based on peak stress using the bot-spot stress concept. From the analyses of the S-N curves obtained, we have concluded that there is a need to develop a new method to evaluate the fatigue life.