Abstract:
Very high cycle fatigue (VHCF) tests were carried out by using the carburized CrMn steel. By observing the fracture surface, three different failure modes were distinguished, namely the surface-crack induced failure mode and the inclusion induced failure mode under HCF (5×10
4<
N<10
7) and VHCF (
N>10
7) conditions. The
S-
N curves were assumed for each failure mode in the present study. Based on the mixed Weibull distribution, the Basquin
S-N curve and the three-parameter
S-N curve, the probabilistic
S-N (
P-S-N) curves were established for three different failure modes respectively, and a method for constructing the
P-
S-N curve associated with multiple failure modes was developed. In comparison with experimental data, the fatigue life predicted by the
P-
S-N curve with 99% survival probability is acceptable at VHCF regime.