疲労強度データベースに基づく炭素鋼および合金鋼平滑試験片の疲労寿命の分散分布に関する研究

抄録

The purpose of this study is to determine the distribution characteristics of the variances of fatigue lives of carbon and alloy steels, especially from the viewpoint of their dependence on applied stress levels. The database used in this analysis is the "Database on Fatigue Strength of Metallic Materials" compiled by the JSMS (The Society of Materials Science, Japan) Committees on Fatigue and Reliability Engineering. By quantitave analysis of the variances of fatigue lives of carbon steels on logarithmic normal distribution papers, simple expressions to give the median value and the value at several percentage points are formulated as functions of the applied stress. Results for alloy steels indicate that the scatter of the variance becomes notably large at the lowest stress level, presumably depending on the defect sensitivity of high strength alloy steels. Accordingly, the distribution characteristics of fatigue lives at those low stress levels should be considered carefully in engineering applications.