Notch fatigue analysis and life assessment using an energy field intensity approach in 7050-T6 aluminium alloy under bending-torsion loading

This paper studies the fatigue crack initiation and fatigue crack propagation of notched cylindrical bars made of 7050-T6 aluminium alloy subjected to multiaxial bending-torsion loading. The sites of crack initiation and the angles of crack initiation were successfully predicted from the distribution of the first principal stress at the notch surface. Fatigue crack initiation lives were computed through the new concept of energy field intensity formalised in a linear-elastic framework along with a local stress-strain model for notch plasticity analysis. Regardless of the model used to compute the cyclic response at the geometric discontinuity, fatigue life predictions were in good agreement with the experimental observations.