A theoretical treatise for notch and defect sensitivity under torsion

A sound theoretical study on defect and notch sensitivity under torsion loading is carried out, with the aim to extend to mode III a diagram proposed some years ago by Atzori and Lazzarin, which makes explicit the bridging at the fatigue limit between defect sensitivity and notch sensitivity under tension loading. Analogies and differences between the previous and the new diagram are highlighted. Finally some new expressions for the notch sensitivity under torsion are presented as well.