Statistical Estimation of S-N Curves for Aluminum Alloys Based on Their Static Mechanical Properties

Abstract

A statistical estimation method of S-N curve for aluminum alloys using their static mechanical properties was proposed. Firstly, S-N data series for aluminum alloys were extracted from "Database on Fatigue Strength of Metallic Materials" published by the Society of Materials Science, Japan (JSMS) and semi-logarithmic curve model was applied as mathematical regression model based on the JSMS standard, "Standard Evaluation Method of Fatigue Reliability for Metallic Materials -Standard Regression Method of S-N Curves-". Secondly, correlations between each pair of regression parameters and static mechanical properties were investigated. Using these correlations, S-N curve for aluminum alloys could be predicted easily from the static mechanical properties. Moreover, using (1) the distribution of regression parameter D and (2) the distribution of fatigue strength at 10⁷ cycles, the percent points for the predicted S-N curve was evaluated. As result, it was confirmed that over 70% of S-N data series of wrought aluminum alloys fall within the range of estimated interval between -3s and +3s, where s means a standard deviation for the parameter of D.