Military Gas Turbine Engine High-Cycle Fatigue (HCF) Mitigation

The 1999 HCF Probabilistics Steering Committee meeting indicated that material behavior is a leading root cause of HCF problems in blades, vanes, and seals. A conventionally used component lifing practice is to conduct a Goodman type analysis to estimate the resistance to HCF failure. However the true resistance of a component to HCF loading is dependent on the steady and vibratory stress gradients and the stressed volume of material. Because Goodman diagrams are based on specimens of simple geometry that do not have the same stress gradients as the component, the Goodman diagram provides only a rough estimate of fatigue response. This SBIR will build on an existing VEXTEC material fatigue response model, MICRO (microstructural-based probabilistic fatigue analysis), to properly account for the multi-scale aspect of early fatigue damage that drives the scatter in fatigue response. The ultimate SBIR objective will be to develop capability for accurately predicting HCF damage effects for a complex component (JSF 1st stage fan blade) based on a minimal amount of simple specimen data. In effect, this product will be a computationally efficient Goodman analysis that will allow for accelerated design analysis, redesign avoidance, less testing and minimal build-in design conservatism.