Damage Tolerance Analysis of Grinding Burn Cracks in High Strength Steels

The United States Air Force (USAF) has identified the need for the development of damage tolerance methodologies to address grinding burns in high strength steel.Our team proposes a holistic approach for damage tolerance assessments in landing gear components (and other high-strength steel components) that focuses not only on grinding burns but also on other failure mechanisms, such as corrosion pitting, the attempted repair of which is often the precipitating event for introducing grinding burns. Our team proposes a technical plan that considers component criticality, defect criteria for grinding burns and other physical damage states (such as corrosion pitting), residual stress effects in crack growth analyses, and mitigation schemes to stop damage propagation using engineered residual stress.The technical plan defined in the first phase shall be implemented in Phase II to provide robust data for model development. Delivery of a fully functional analytical toolkit is scheduled, per USAF guidelines, in Phase III.Our team plans to use previously developed corrosion structural effects analysis methods, residual stress / crack growth analysis methods, successful experience with laser peening, and a strong transition record to provide the USAF with a comprehensive solution package that works seamlessly within the ASIP framework.