Low-temperature fatigue life properties of aluminum butt weldments by the means of the local strain energy density approach

Abstract

The paper investigates the use of the strain energy density evaluated on a finite control volume as a mean to the fatigue life prediction for double V-groove but joints. The specimens are manufactured by metal active gas (MAG) welding of AA6082-T6, fatigue tested in as weld condition by loading orthogonally to the welding direction with a load ratio R = 0 and R = 0.5. The aim of the paper is to apply the strain energy density (SED) method to butt-welded joints and verify its soundness for this class of joints, comparing the test result with numerical solutions. A comparison of the fatigue results using and SED method both nominal stress approach is reported. A numerical model has been realized in plane strain hypothesis from an ideal nondistorted geometry and the stresses corrected according to the average specimen measures. The results show an agreement of the fatigue resistance with the nominal stress S-N curves and the SED curve for aluminum welded joints both at room temperature (+25°C) and at arctic temperature (−60°C).