Geometry of Pre-corrosion Pit-induced Fatigue Crack on Aluminum Alloy Panel

Corrosion pit induced fatigue crack propagation can not be adequately predicted solely by stress-intensity factor (SIF) analysis,due to variation in the stress field along the pit border. Analysis of surface pit-induced cracks was performed considering the variation in stress field using the concept of crack closure. Changes in geometric parameters describing the pit-induced crack were studied. It was shown that the geometry variation of pit-induced crack was independent of stress range and material properties. Experiments were performed to assess the accuracy of the analysis,which yielded excellent results.