Statistical analysis of fatigue crack growth for 16MnR steel under constant amplitude loads

A statistical investigation of the fatigue crack propagation process has been carried out. Twenty-one pre-cracked specimens obtained from the same sheet of Chinese steel 16MnR were subjected to identical load and environmental conditions. Tests were conducted under constant amplitude loads in order to study the effect of material property randomness. From the experimental data, the distribution of the crack size at any given number of cumulative load cycles, or the distribution of the number of load cycles to reach any given crack size, is determined. The statistical distribution of the crack growth rate at any given number of load cycles or at any given crack size is also discussed. The statistical investigation methods of the fatigue crack propagation process, proposed by this article, were also found to be suitable for other materials.