Sickle-shaped cracks in metallic round bars under cyclic eccentric axial loading.

In the present paper, the fatigue propagation of an initial sickle-shaped surface crack in a metallic round bar under eccentric axial loading acting perpendicular to the crack plane is examined. Firstly, the stress-intensity factor (SIF) along the crack front is determined through a three-dimensional finite element analysis and the one-quarter point displacement method, for different values of the loading eccentricity. Then, the fatigue behaviour of the cracked bar is numerically analysed by a step-by-step procedure based on the Paris-Erdogan law. The results are plotted in terms of crack paths, intersection angle and crack depth evolution, by varying the loading eccentricity.