Advanced Modeling to Characterize Failure Progression Rates from the Incipient Stage to Component Failure

"Advanced failure progression modeling will be demonstrated on selected gear and bearing components for the purpose of providing a basis for fully enabling the Prognostics and Health Management (PHM) to assess the remaining useful life of components andtheir risk to catastrophic failure. Fracture Mechanics methods within a framework of Finite Element Analysis (FEA) will be applied to a crack in the root of a spiral gear tooth to simulate crack growth to final failure. The gear selected for analysiswill be one of those for which the Naval Air Warfare Center (NAWC) has generated full scale H60 helicopter drive system testing. The data will provide a basis for validating the model. Additional fracture mechanics analysis will be developed to determinea risk factor for catastrophic bearing inner ring fracture in the presence of a fatigue spall. The risk factor will be based on sensitivity to fracture of bearing geometry, bearing/shaft interference fit, material fracture toughness and operating speedand load. The models provide benefit by more accurately predicting the remaining useful life of components. Model development will provide a basis for: (1) developing improved diagnostic algorithms for fault detection, (2) assessing the risk tocatastrophic failure of detected bearing faults, (3) understanding component failure progression rates, and (4) determining more accurate inspection and maintenance intervals. Commercial applicatio