At IRDL, Mathilde Renault explored the impact of surface treatments on the fatigue of structures in additive manufacturing.
Mathilde Renault, chercheur·e au sein de IRDL (Institut National Polytechnique de Bretagne).
Thèse soutenue en 2025 à l'école doctorale École doctorale Sciences pour l'ingénieur et le numérique.
Référencée dans le réseau ABES/STAR, cette thèse répond aux critères de rigueur de l'enseignement supérieur français.
Additive manufacturing, and more specifically the wire arc additive manufacturing (WAAM) process, represents a significant and revolutionary advancement in the production of complex metal parts, allowing for more flexible design and a reduction in waste. However, the surface finish of the produced parts remains a major and concerning challenge, limiting their fatigue performance, a crucial aspect for the durability and reliability of components in demanding environments. This thesis by Mathilde Renault, conducted at the Research and Development Institute in Languedoc (IRDL), addresses this technological lock by examining how different surface treatments can improve the fatigue resistance of marine propeller blades made of copper-aluminum, a material particularly suited for maritime applications due to its corrosion resistance.
The results obtained from this research are promising and open up interesting perspectives. Indeed, a 30% reduction in the material used for the production of solid blades has been validated by Bureau Veritas, demonstrating increased efficiency in the manufacturing process. This reduction in material is not only a matter of cost but also of environmental impact, as it contributes to more sustainable manufacturing. Furthermore, the deposition rate reaches several kilograms per hour, paving the way for large-scale production, essential to meet the growing needs of the maritime and aerospace industries. These advancements could transform not only these sectors but also the entire industrial ecosystem in West Africa, offering lighter and more sustainable solutions.
However, several questions remain unanswered and deserve further exploration. How can these surface treatments be standardized for widespread adoption in the industry? What are the economic implications for companies that choose to integrate these new methods? It is essential to explore these avenues to maximize the impact of this research and ensure that the results can be applied practically and effectively in the sector. Companies must also assess the investment costs associated with implementing these new technologies against the long-term benefits they may derive from them.
The methodology adopted by Renault includes the characterization of surface states and the analysis of fatigue failure mechanisms, approaches that allow for a better understanding of the interactions between surface treatments and the mechanical properties of the parts. These analyses are crucial for establishing correlations between the different treatments applied and the observed fatigue performance. The strategic recommendations arising from this research include the development of finishing treatments, which could be adapted to the specificities of the materials used, as well as the development of a sizing method suitable for treated surfaces. These actions aim to optimize the fatigue resistance of parts manufactured by WAAM, thereby contributing to the advancement of additive manufacturing technologies in West Africa, where the need for innovation is pressing.
In summary, this thesis is not limited to a simple academic exploration. It proposes concrete solutions for the industry while raising crucial questions about the future of additive manufacturing. Decision-makers must take these results into account to guide their investments and public policies towards sustainable and economically viable manufacturing practices. By integrating this new knowledge, industry players will not only improve the quality of their products but also strengthen their competitiveness in the international market. The implications of this research go beyond simple technical applications; they also touch on the necessity of a transition to more environmentally friendly and economically viable production methods, a major challenge for the future of the industry in West Africa.
Données clés
- 30% : Réduction de la matière utilisée pour la fabrication de pales pleines, validée par le Bureau Veritas.
- plusieurs kg/h : Taux de dépôt pour la fabrication de grandes pièces.
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Sources et accès
Mathilde Renault. Influence de l’état de surface sur les propriétés en fatigue des structures obtenues par fabrication additive arc-fil : état brut, martelé et parachevé jet d’eau. Matériaux. École Nationale Supérieure de Techniques Avancées, 2025. Français. ⟨NNT : 2025ESTA0008⟩. ⟨tel-05471152⟩