Surface cracks in round bars under cyclic tension or bending.

The fatigue growth of a surface crack in a metallic round bar under cyclic tension or bending is analysed. The stress-intensity factor (SIF) along the crack front is computed through a three-dimensional finite element analysis and the one-quarter point displacement method. The results are compared with those presented by other Authors. Then, the fatigue behaviour of the cracked bar is numerically determined by a step-by-step procedure