The Theory of Critical Distances to estimate finite lifetime of notched components subjected to constant and variable amplitude torsional loading

The present paper summarises an attempt to reformulate the Theory of Critical Distances to extend its use to those medium-cycle notch fatigue situations involving both constant and variable amplitude torsional load histories. The accuracy and reliability of the proposed approach was systematically checked not only through several data sets we generated, but also through fatigue results taken from the technical literature. The obtained high level of accuracy seems to fully support the idea that the Theory of Critical Distances is a powerful tool suitable for designing notched components against torsional fatigue.

► The TCD is successful in estimating finite lifetime under constant amplitude torsional loading.
► The TCD is successful in estimating finite lifetime under variable amplitude torsional loading.
► The TCD can be applied by directly post-processing the results from conventional linear-elastic FE models.