Casting defects mechanical impact on turbine blades fatigue life - Engine feedback analysis

Abstract: Aircraft engines are complex, value-added high-tech systems, which possess very restrictive technical specifications. This is especially the case for turbine parts which are submitted to very hostilethermo-mechanical environments. The technical properties, such as fatigue life and creep tolerance of these parts are therefore of primary concern. The properties of the parts are also strongly linked to the manufacturing processes. Unfortunately, these processes possess inherent flaws that lead to the presence of unwanted abnormalities. Fordesign optimization and cost efficiency, great care and efforts are put by the aircraft engine manufacturers to consistently increase the knowledge on these irregularities and their impact on theparts functional characteristics. These issues are still present in the actual industrial context of SAFRAN Aircraft Engines. After successfully completing the development and certification phases, the LEAP, the new enginegeneration that will progressively replace the CFM engine family, is now in its ramping-up production phase. To achieve what will be the greatest production rate increase of all aviation history, crucialcost reduction campaigns are conducted. Among the many potential cost reduction levers, the scrapped parts rate is of primary importance as it represents a significant loss in production. Tolerances of the technical specifications, which hadpreliminarily been established with strong safety margins, are now looked into. In this context, a joint project between the Development Department and the Material Department has been launched to understand more clearly how the metallurgical abnormalities impact the life ofcasting parts, and how this could help optimize the casting defect tolerances.