Fatigue behaviour of AlMgSi tubular specimens subjected to bending–torsion loading

The work here presented is concerned with an experimental and numerical fatigue behaviour study of tubular specimens. Welded and notched tubular specimens of AlMgSi T6 alloy were submitted to in-phase bending–torsion tests. For both geometries, correlation of the fatigue lives was satisfactorily obtained by the distortion energy hypothesis based on the local stresses. A stress–strain field intensity approach and a novel energy-based approach were used to predict the fatigue lives. The applicability of fictitious radius concept at the welded toe was also tested. Comparison between referred theoretical predictions and experimental results reveal reasonable correlations, taking into account the scatter normally observed in fatigue results.