On the most dangerous V-notch

The determination of the failure load for brittle or quasi-brittle specimens containing a re-entrant corner has been faced by several authors, whose approaches are available in the Scientific Literature. However, up to now, little attention has been paid to the presence of a minimum, i.e. an angle at which the critical load attains its minimum value. Even if the minimum was detected in several experiments, it was not highlighted or it was considered as a mere consequence of the scattering of experimental data. Restricting the analysis to a sharp V-notched infinite slab under a remote tensile load, the problem is fully investigated in this paper. It is shown that a minimum, more or less pronounced according to the brittleness number, is always present. It means that the edge crack is not the most dangerous configuration, although the notch opening angle providing the minimum failure load tends to vanish for large notch depths as well as for very brittle materials.