The successful integration of the contra-rotating open rotor (CROR) technology requires an accurate prediction of the fatigue life of IN718 parts. To this end, the life assessment approach for parts with visible or barely visible surface damages generated during service life or inspection activities needs significant improvement.
The typical damage generated can be classified as nicks, dents and scratches (NDS) and they are usually small and difficult to characterise in shape. Moreover, there is a lack of knowledge on how they affect the local residual stresses and, consequently, the fatigue life. Scientific literature on typical materials for aeronautic applications (Ti-based and Ni-based alloys) have proven that the residual stresses around the NDS may have a beneficial effect on fatigue life. Nevertheless, a thorough study that correlates NDS with fatigue life in IN718 in a statistically robust way has never been developed. Consequently, the current design codes neglect the potential benefit of impact residual stresses leading to a conservative approach.
FLECTION seeks to advance the state-of-the-art by developing and validating a combined numerical-experimental approach to assess, with a robust statistical prediction, safe life in IN718 components damaged with NDS. This is expected to contribute to the specific impacts of the Clean Sky Engines AIDP-LPA Platform 1 to reach flight test of the CROR demo-engine and ensuring TRL 6, fulfilling future market needs and enhancing the competitiveness of the European aeronautical industries.
