CRACK-PROPAGATION UNDER CYCLIC LOADING

The crack propagation of a semi-elliptical surface flaw subjected to cyclic combined axial and bending loadings with constant amplitude is numerically examined according to Paris-Erdogan law. The critical crack, for which a given number of cycles is necessary to cause fatigue failure, can be determined from interaction between the theoretical results obtained and the experimental data of the Wohler curves. Some examples are presented for different stress ranges DELTA-sigma(t) and loading eccentricities given by e = M/F, where F and M are the axial force and the bending moment, respectively.