On the prediction of initiation life for fatigue crack emanating from small cold expanded holes

The cold expansion method is an effective method widely used for retarding the initiation of the fatigue crack. In the present work, the finite element analysis is performed to determine the residual stress distribution around the cold expanded hole and the ɛ − N method is implemented to predict the fatigue crack initiation lives. The superposition of the mean stress is used to analyze the fatigue crack initiation. It is found that the effect of Kf, which decreases the Kt effect, must be taken into account for the small stop-hole. Estimates of the fatigue life quantities correlate well with the experimental results.

► The residual stress after cold expansion is determined by 3D finite element analysis.
► Short crack behavior reduces the stress concentration at the root of elongated notch.
► Kf caused by short crack is used to predict the initiation life of fatigue crack.