Interacting Effects Induced by Two Neighboring Pits Considering Relative Position Parameters and Pit Depth

For pre-corroded aluminum alloy 7075-T6, the interacting effects of two neighboring pits on the stress concentration are comprehensively analyzed by considering various relative position parameters (inclination angle θ and dimensionless spacing parameter λ) and pit depth (d) with the finite element method. According to the severity of the stress concentration, the critical corrosion regions, bearing high susceptibility to fatigue damage, are determined for intersecting and adjacent pits, respectively. A straightforward approach is accordingly proposed to conservatively estimate the combined stress concentration factor induced by two neighboring pits, and a concrete application example is presented. It is found that for intersecting pits, the normalized stress concentration factor K_tnor increases with the increase of θ and λ and always reaches its maximum at θ = 90°, yet for adjacent pits, K_tnor decreases with the increase of λ and the maximum value appears at a slight asymmetric location. The simulations reveal that K_tnor follows a linear and an exponential relationship with the dimensionless depth parameter R_d for intersecting and adjacent cases, respectively.