Corrosion Fatigue Model for Next-Generation Damage Tolerant Life Prediction and Management of Aircraft Components

ABSTRACT:Although a great deal of success in structural integrity management of aircraft using damage tolerance concepts has been achieved, this may be realized by excessively conservative assumptions, high inspection burdens, and aggressive maintenance and repair strategies. Even with these conservative processes, instances of early failure can occur. There is a recognized need to improve structural integrity calculations through the inclusion of the effect of existing corrosion damage on fatigue. To address this critical need, a computational model will be developed that utilizes finite element analysis and linear elastic fracture mechanics techniques to predict fatigue life of aircraft components based on measured environmental usage spectra and the subsequent corrosion damage. A severity map indicating remaining useful life across the component will be useful for indicating hotspots where crack initiation and failure is likely. The modeling tool will leverage Luna corrosion models and test and measurement systems and corrosion fatigue research ongoing at the University Virginia. This approach will provide the Aircraft Structural Integrity Program (ASIP) community with software for next-generation damage tolerant prediction of corrosion fatigue of high-performance aluminum alloy components to ensure the readiness and structural integrity of aircraft.BENEFIT:A successful development effort will result in a corrosion fatigue model for life prediction of high-performance aluminum alloy aircraft components. The technology will be useful for establishing the susceptibility for failure of a specific designed component and developing a corrosion prevention and control program and supporting structural maintenance based on a combination of actual usage data and life predictions from the model. The technology would have value to a wide range of DoD and civil infrastructure assets along with commercial products. The initial customer for the corrosion fatigue prediction software is the AFRL Corrosion IPT and broader Air Force corrosion and sustainment community. The most immediate market opportunities will be within the Air Force and DoD aviation corrosion research communities to predict and test aircraft materials and component performance. Besides early adopters in the aviation community, other DoD applications would include ships, ground vehicles, and support equipment. Commercial industries that would benefit from improved structural integrity management include transportation (automotive/aerospace/shipping) and infrastructure (coastal and offshore structures).