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Fatigue Properties of Rail Steel Under Constant Amplitude Loading and Variable Amplitude Loading

일정 및 변동하중하의 레일강의 피로특성

Kim, Cheol-Su;Kim, Jeong-Gyu
김철수;김정규

  • Published : 2001.04.01

Abstract

In this study, fatigue growth behavior of the transverse crack, which was the most dangerous damage among the various types of rail defects, was investigated using the notched keyhole specimen under constant amplitude loadings. Fatigue limit of smooth specimen in rail steel at R=0 was 110MPa, and the fatigue crack initiation life in the region of the low stress amplitude (ie. long life) occupied the major portion of the total fatigue life. The fatigue strength under variable amplitude loading was converted to the equivalent fatigue strength based upon. Miners rule, which was estimated approximately 9% lower than that under constant amplitude loading. Also, in the low ΔK(sub)rms region ($\leq$21MPa√m), fatigue crack growth rate (da/dN) under constant amplitude loading was higher than that under variable amplitude loading, whereas the tendency was reversed in the high ΔK(sub)rms region. It is believed that this behavior is due to the transition of fracture appearance.

Keywords

Detail Fracture;2-Parameter Weibull Distribution;Cumulative Distribution Function;Fatigue Notch Factor

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