Statistical Estimation of S-N Curves for Structural Carbon Steels Using Their Static Mechanical Properties

Abstract

A statistical estimation method of S-N curve for structural carbon steels using their static mechanical properties was proposed. Firstly, S-N data series for pure iron and structural carbon steels were extracted from "Database on Fatigue Strength of Metallic Materials" published by the Society of Materials Science, Japan (JSMS) and S-N curve for each material was obtained by using the JSMS standard; "Standard Evaluation Method of Fatigue Reliability for Metallic Materials -Standard Regression Method of S-N Curve-". Secondly, correlations between regression parameters and static mechanical properties were investigated. As a result, the relationships between regression parameters and static mechanical properties (e.g. fatigue limit E and static tensile strength σ_B) have showed significant correlations. Based on these correlations, S-N curves for structural carbon steels were successfully predicted from their static mechanical properties. Moreover, using the distribution of fatigue limit E, the percentile points for the predicted S-N curve were also estimated. It was finally confirmed that 81% of S-N data series fall within the range of estimated interval between -3s and +3s, where s means a standard deviation.