Selection of the Best Method for Assessment of the Fatigue Life of Aluminium Alloys Based on the Root of the Scatter Mean-Square Value

The paper presents comparison of three methods of fatigue life assessment related to aluminium alloys. One of these methods is a new way of statistical interpretation of the fatigue test results by means of the root of the mean-square value of the error expressing a half of scatter of the calculated fatigue life. The results of fatigue tests of specimens, and different geometries of welded joints made of aluminium alloys were considered. The calculated fatigue lives were obtained with use of critical plane orientations determined according to the variance of normal and shear stresses, and the covariance of normal and shear stresses.