Crack tip shielding and size effect related to parallel edge cracks under uniaxial tensile loading

The present work aims at investigating crack shielding and size effect related to a cracked slab under tensile loading. For this purpose, experimental tests are carried out on PMMA cracked samples. Three different geometries are taken into account, presenting one, two or three parallel edge cracks, and assuming their distance equal to their initial length. Results are interpreted through the coupled stress and energy criterion of Finite Fracture Mechanics (FFM). The approach is implemented numerically, and parametric finite element analyses are carried out to evaluate the normal stress field and the stress intensity factor for each configuration. It is found that asymmetric crack propagation has to be preferred according to the energy balance. The matching between FFM failure predictions and experimental data reveals to be satisfactory.