Induced out-of-plane mode at the tip of blunt lateral notches and holes under in-plane shear loading

As it is well known the Poisson's effect in a cracked plate subjected to anti-symmetric plane loading leads to the generation of a coupled out-of-plane singular mode. Recent theoretical and numerical analyses have shown that this effect is present also in plates weakened by sharp V-notches and might play a role in failure initiation phenomena of notched plates subjected to Mode II loading, especially in the presence of a large notch opening angle. Dealing with blunt notches with a large notch radius, and not just with sharp notches, the presence or not of an out-of-plane mode does not appear to have been systematically investigated in the past. The main aim of this work is to confirm the existence of the stress field associated with the out-of-plane mode (Mode O) and to describe its main features in the presence of a notch radius significantly different from zero. The analyses include U-notches, as well as circular and elliptic holes. The strain energy density in a 3D control volume is utilized to identify the most critical zone (with respect to failure initiation) through the plate thickness at the notch tip.