Numerical modelling of crack shape evolution for surface flaws in round bars under tensile loading

This paper proposes a numerical procedure for calculating the crack shape evolution in semielliptic surface flaws in round bars under tensile loading, studying how the aspect ratio (relation between the semiaxes of the ellipse) changes with the relative crack depth. It was been assumed that each point at the crack front advances in direction perpendicular to such a front, according to the Paris–Erdogan Law. The stress intensity factor was computed using a triparametric expression proposed in the scientific literature. Numerical results of the present model agree fairly well with experimental results obtain in real prestressing steel wires tested in fatigue.