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INFLUENCE OF DEFORMATION ON THE COATING PROPERTIES OF AIRCRAFT FUSELAGE SHELLS

1 JEPKENS Jan
Co-authors:
1 HEIMES Norman 1 WESTER Hendrik 1 MÜLLER Philipp 1 HÜBNER Sven 2 WEHRMANN Simon 2 MÜLLER Matthias 1 BEHRENS Bernd-Arno
Institutions:
1 IFUM - Leibniz University Hannover, Hannover, Germany, EU, jepkens@ifum.uni-hannover.de, heimes@ifum.uni-hannover.de, wester@ifum.uni-hannover.de, mueller@ifum.uni-hannover.de, huebner@ifum.uni-hannover.de, behrens@ifum.uni-hannover.de
2 Deharde GmbH, Varel, Germany, EU, s.wehrmann@deharde.de, m.mueller@deharde.de
Conference:
32nd International Conference on Metallurgy and Materials, Orea Congress Hotel Brno, Czech Republic, EU, May 17 - 19, 2023
Proceedings:
Proceedings 32nd International Conference on Metallurgy and Materials
Pages:
380-385
ISBN:
978-80-88365-12-9
ISSN:
2694-9296
DOI:
https://doi.org/10.37904/metal.2023.4659
Published:
8th January 2024
Proceedings of the conference were published in Web of Science.
Metrics:
281 views / 192 downloads
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Abstract

Manufacturers like Airbus have strict specifications concerning the process sequence of fuselage shell forming. Coating may only take place after forming, because conventional processes induce large deformation which could cause coating failure. A novel incremental bending process known as Deharde Polygon Forming® (DPF®), has the potential to challenge existing process sequence restrictions due to lower deformations. Thus, it is to be investigated if precoated sheets can be formed by DPF® with regard to the coating properties. Correspondingly, in the scope of this work, starting from the initial state of coated EN AW - 2024 - T351, the changes of the Seevenax-313-81 coating after preloading were analysed. Therefore, three different strain states were induced by Marciniak tests and scaled fuselage shells were produced by DPF® from which specimen were obtained. Afterwards, the evolution of coating properties such as hardness, Young's modulus, elastic and plastic behaviour and friction coefficient were investigated by scratch and indentation tests with a Triboindenter TI 950. In parallel, the formed specimens were analysed for coating failure by using integrated optics. It was found, that the pre-stretched specimens by Marciniak tests and scaled DPF® do not undergo significant changes in the application characteristics of the coating. However, the former was found to have cracks in the coating. In contrast, for scaled DPF® fuselage shells, where compressive stresses are induced by contact with the tool or spring steel package, no failure were detected in the surface of the coating. The results indicate potential for flexibilization of the process chain regarding forming and coating.

Keywords: Coating properties, nanoindentation, Marciniak tests, incremental bending, fuselage shells

© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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