Physics Based Gear Health Prognosis via Modeling Coupled with Component Level Tests Navy STTR FY2007 Sol No.: Navy STTR FY2007 Topic No.: N07-T010 Topic Title: Physics Based Gear Health Prognosis via Modeling Coupled with Component Level Tests Proposal No.: N074-010-0349 Firm: VEXTEC Corporation 750 Old Hickory Blvd, Building 2, Suite Brentwood, Tennessee 37027 Contact: Richard Holmes Phone: (615) 372-0299 Web Site: www.vextec.com Abstract: PHM investments can successfully diagnose up to 70% of damage fault indications. The cost of empirically-based testing is very high and must be reworked for every gear system design change. Physics-based FEA combined with long crack modeling can be self-adapting and overcome the high cost of pure statistical approaches but still unable to diagnose the remaining 30% failures because onset of damage is too small and happens too quickly. VEXTEC has already developed techniques for modeling damage at the fundamental microstructural level which will uniquely be applied to gear system PHM under this STTR. The modeling properties include geometry, composition, material characteristics, case hardness, core hardness, case depth, design ratios of case to tooth thickness, surface finish, and machining are directly and explicitly addressed in the formulation of the micromechanical material model. The objective of this STTR is to develop physics-based failure models to allow for explicit prognosis of air vehicle gear components and systems. This project provides for successful modeling of the effects of tooth bending, spalling, and pitting to advance the understanding of these failure modes as a critical and new approach to aerospace application prognosis. Benefits: The conventional vibration-based gear fault detection method relies on multiple rig tests of actual hardware. Complete characterization of gear faults can run as high as $10 million for each design assuming multiple full scale engine runs are required. Virtual simulation can reduce test costs by more than 50%. Return