Variations on a critical distance theme

We investigate how the fatigue limit of notched specimens calculated with the Theory of Critical Distance (TCD) changes when variations in the value of the critical distance itself are considered. We motivate our study by showing how attempts at introducing a plastic zone correction in the derivation of the formula for the critical distance lead to a new length which can be significantly larger than the original one. The predictions effected with both lengths were not found to be so different, though. And this led us to study circular holes and V-notches, for which solutions for the ratio K-f/K-t can be derived analytically.

Automated summary

This study investigates the changes in fatigue limit of notched specimens calculated with the Theory of Critical Distance when variations in the value of the critical distance itself are considered. Despite the introduction of a plastic zone correction leading to a new length significantly larger than the original one, the predictions using both lengths were found to be similar. Analytical solutions for the ratio K-f/K-t were derived for circular holes and V-notches as a result of this research.