A short and long crack growth model with mean stress correction based on cyclic resistance curve

In the study, the Chapetti cyclic resistance curve is modified by a R-dependence model based on the cyclic strain energy density to account for the mean stress effects on the long crack propagation threshold and fatigue limit. Accordingly, the crack growth model of the modified NASGRO with mechanically short crack extension and Kitagawa-Takahashi diagram are derived with mean stress sensitivity. Relatively good accuracy can be achieved in terms of the near-threshold propagation behaviors and S-N curves at high cycle regime including engineering aluminum alloys and titanium alloys.