Abstract
The reduction of crack tip stresses due to specimen thickness, crack depths and across the thickness was examined using fracture mechanics testing and finite element analysis. This reduction of crack tip stresses was correlated with the fracture resistance. A correlation between in-plane, out-of-plane constraint, and the constraint through the thickness with fracture toughness was established. It was observed that testing deeply thin geometries provide similar fracture resistance to that measured on shallow thick geometries. The study revealed that fracture toughness data determined from different specimens’ thicknesses can now be obtained by testing only a series of specimens of one size, inherently less material and short time are required. The application of this research findings of geometries with low constraint conditions exist in non-standard fracture testing are economically beneficial in fitness-for-service (FFS) assessment as it allows to define precisely the failure condition and to avoid the unnecessary replacement while maintaining component integrity.