Influence of curvature of the crack tip radius on stresses

In experimental mechanics, when conducting research on models, the question often arises of whether it is legitimate to replace a crack with a cut, whether the radius of curvature of the cut will have a large effect on the magnitude of stresses near its apex. In order to understand these questions and give answers to them, a number of experiments were carried out on samples made of piezo-optical material (Plexiglass of E2 grade). In the models, the crack was simulated using a cut, then a hole was made at the top of the cut with a drill. The models were investigated in pure bending by the photoelasticity method. Stress fields were obtained in two batches of samples at different loads. The intensity of stresses near cracks-cuts at different radius of curvature of their tops was determined by using the experimental data. An assessment of the influence of the crack-cut tip radius curvature on the magnitude of stresses near it has been carried out.