Fitness-for-Service Analysis of the Interplay Between a Quarter-Circle Corner Crack and a Parallel Semi-Elliptical Surface Crack in a Semi-Infinite Solid Subjected to In-Plane Bending Part II—The Effect on the Semi-Elliptical Surface Crack

The impact of a quarter-circle corner crack on an adjacent parallel semi-elliptical surface crack (SESC) located in a semi-infinite solid subjected to in-plane bending is studied using a 3-D finite element analysis. The stress intensity factor (SIF) distributions along the front of the SESC are evaluated to determine said impact. The SESC’s semi-major axis ranged from a₁ = 10 mm to 30 mm with ellipticities of b₁/a₁ varying from 0.1 to 1.0 for a constant quarter-circle corner crack length of a₂ = 15 mm. Furthermore, several crack configurations are considered where the normalized vertical and horizontal gaps between the two cracks are taken to be H/a₂ = 0.4 and 1.2 and S/a₂ = −0.5 and 1.0, respectively. The results show that the effect of the quarter-circle corner crack on the SESC can be considerable both in amplifying and in attenuating the SIFs along the semi-elliptical surface crack front. Moreover, these opposite effects can occur simultaneously, but in different sections of the SESC’s crack front. The magnitude and pattern of these effects depend on the length and ellipticity of the SESC. It is further concluded that when considering the fitness-for-service of a critical real mechanical component, a complete 3-D analysis is needed to provide a reliable solution for such crack configurations.