Nomenclature

A methodology is presented for application of stress results from three dimensional finite element models for use in fracture mechanics computations. It is based on the assumption that a fatigue crack propagates in a plane normal to the maximum principal stress in a region that can be idealized as a rectangular plate. The methodology, recently implemented in the DARWIN ® probabilistic fracture mechanics program, is demonstrated for (1) a finite width plate with a centrally located hole and (2) an aircraft gas turbine engine rotor disk. Computational error associated with the methodology is less than 1 % compared to analytical and finite element solutions. The results can be applied to the probabilistic life prediction of components subjected to surface damage