This Phase II proposal describes the continued development of three-dimensional, nonlinear structural analysis methods for use in prognosis systems for aerospace, gas turbine, metallic components and component assemblies. In Phase I, Fracture Analysis Consultants Inc. (FAC) demonstrated the feasibility of using a three-dimensional fracture propagation program, Franc3D/NG, to automatically generate finite element models that relate sensor-measurable structural response to damage scenarios involving fatigue cracks. These numerical results were used to generate probabilistic predictions of remaining useful component life. In Phase II, FAC proposes to work closely with Pratt & Whitney to expand on the Phase I work with four key areas of emphasis. First, we propose to incorporate realistic engine loads, such as combined high and low frequency cycling, and realistic materials, such as single crystal alloys. Second, we propose to incorporate advanced 3D fracture mechanics, including mixed mode I, II, and III loading, orthotropic material behavior, and crack growth in residual stresses due to surface treatments. Third, we propose to verify the software using historical and newly generated test results. Fourth, we propose to verify the software and demonstrate its usefulness and usability in an actual engine development and production environment.
Keywords: Prognosis, Turbine Engines, Analysis Methodology, Fatigue Life Prediction, Fatigue Crack Growth
