Early detection and progress monitoring and prediction of corrosion in aeronautic al alloys through calibrated ultrasonic corrosion sensors application
Corrosion is a dynamic process in which propagation rate remains difficult to predict and varies depending on the type of corrosion occurring (pitting, intergranular, exfoliation,filiform, corrosion-fatigue and SCC). Currently, the presence of corrosion damages may be detected by means of NDT. However, corrosion initiation and mechanism behind the defect cannot be distinguished by currently used methods. As consequence, an early detection of corrosion is not done and corrective actions are only performed when become relevant (cracks, loss of thickness). Therefore, aircraft industry needs sensors able to detect both corrosion initiation and its propagation. Combined with predictive models, it will allow forecasting how damage progresses when paint is degraded.
The main objective of U-CROSS is to design, develop and validate the application of ultrasonic corrosion sensors (UCS), combining passive (Acoustic Emission) and active (Pulse Echo Ultrasonic Testing) types, for corrosion monitoring, enabling them for real time detection of early stages of localized corrosion as well as for monitoring the progress of damages with time. 
A well-defined strategy will be followed to validate its implementation by the development of “model witness blocks” to calibrate sensors, taking into account the intrinsic features of each corrosion mechanism. A thorough selection of the UCSs to be used as cumulative and real-time monitoring will be done depending on corrosion mechanism, and tests will be performed on several indoor and outdoor test rigs.
The project will also provide a software tool (wizard type) to enable end-users to design and use sensors and to predict the number of cycles before critical damage occurs.
3 research organisations, 1 NADCAP accredited SME for testing painted parts and 1 European leader in UCSs manufacturing and ultrasonic inspection join forces in U-CROSS to achieve these ambitious objectives, which will guarantee the future commercialization of the result.