Effect of Mixed Mode Loading Induced by Asymmetrical Stress upon Crack Initiation from Corrosion Pits
This work focuses on determining the influence of mixed stress conditions on the initiation of fatigue cracks from corrosion pits in a UNS S31603 stainless steel. Fatigue limit was established as a threshold stress criteria for fatigue crack initiation from semi-elliptic surface pits. The strain energy release rate range (G) around semi-elliptic surface pits was determined as a function of the pit aspect ratio (depth/major width axes: a/c), pit contour and the orientation of the nominal stress from a linear elastic fracture mechanics approach. Results indicated that stress conditions for crack initiation in mixed mode overcome the minimum stress level or single threshold stress established from the fatigue limit concept. Under mixed mode condition a crack will grow at the surface zone (φ = 0˚) when a/c ≥ 0.60 and for orientation angles from 5˚ to 75.
Alexander Balankin, José Martínez Trinidad and Orlando Susarrey Huerta
N. Acuña-González et al., "Effect of Mixed Mode Loading Induced by Asymmetrical Stress upon Crack Initiation from Corrosion Pits", Advanced Materials Research, Vol. 65, pp. 39-46, 2009