Very high cycle fatigue life and critical defect size: Modeling of statistical size effects

A novel statistical approach to model size effects in very high cycle fatigue (VHCF) is proposed in the paper. The statistical distributions of the VHCF life and of the size of the defect leading to VHCF failure (critical defect) are identified in the paper through the weakest-link principle. The statistical distributions are able to account for the stress gradients that are present in a loaded material volume. An efficient procedure for estimating the parameters involved in the statistical distributions is also shown. The proposed statistical models are finally validated through experimental data taken from the literature. The experimental validation proves the fitting capability of the proposed models that outperform the traditional models based on the 90% risk-volume.