C.ADER: Conservation of ancient Aircrafts: non-destructive Diagnosis of damagEs for a smart coRrosion protection – C-ADER

The preservation of cultural and scientific heritage has been an important concern for centuries. In scientific and technical museums, aluminium is present in almost all collections, from aircraft to spacecraft, from industrial objects to everyday objects. Unfortunately, the aluminum alloys used in these aircraft are very susceptible to corrosion.
The main objective of this research project is to propose to heritage professionals, curators and conservators, new innovative diagnostic and conservation tools to ensure the long-term conservation of aircraft exposed outdoors. This research could allow a more reliable estimation of the risks incurred by these materials in order to define a coherent conservation policy.
To achieve these objectives, our project relies on :
- the development of non-destructive techniques based on the use of non-linear guided waves for the analysis and monitoring of aircraft structures, especially for areas difficult to access. Guided ultrasonic waves generate growing interest because they can propagate over long distances and offer enormous potential in terms of time and cost savings during the inspection of a wide variety of structures. Indeed, guided waves can achieve much greater inspection ranges than conventional ultrasonic inspection methods, as they use the structure itself as a waveguide by exploiting the resonances between the structure's boundaries.
-The development of advanced technological solutions for preservation and maintenance. To rapidly reduce the corrosion rate on some internal parts, an advanced formulation of corrosion inhibitors will be applied. Secondly, new cathodic protection techniques will be developed to protect the corroded aluminum alloys based on different galvanic couplings with the aluminum alloys, in order to ensure long-term corrosion protection and easier maintenance. Preliminary results have shown that low polarization can be sufficient to significantly reduce the corrosion current density and inhibit the pitting phenomenon. Therefore, cathodic polarization of ancient aluminum alloys with a low voltage sacrificial anode such as an activated aluminum anode (Al-Zn (Ga/In)) or a magnesium alloy may be possible to protect ancient aircrafts.
-The development of a specific numerical tool based on a digital twin concept by combining all these data and a digitalization of the aircraft. The objective of this tool is to link the 3D representations of an aircraft to heterogeneous sets of information (documentation, material analysis, iconographic sources, etc.). In this perspective, the data associated in the digital twin can be considered as an integral part of the aircraft. The museum will also create a virtual exhibition in order to share with the public the conservation process developed for the aircraft kept outdoors and the technological aspects of the heritage.