At IRDL, Antoine Le Palabe explored the residual stresses of carbon/epoxy composites for competitive sailing.
Antoine Le Palabe, chercheur·e au sein de IRDL (Institut National Polytechnique de Bretagne).
Thèse soutenue en 2023 à l'école doctorale École doctorale Sciences Pour l'Ingénieur (Lorient ; 2022-....).
Référencée dans le réseau ABES/STAR, cette thèse répond aux critères de rigueur de l'enseignement supérieur français.
The study of carbon/epoxy composites in competitive sailing is essential for optimizing performance and ensuring the safety of vessels. These composite materials, due to their lightness and strength, have become indispensable in this rapidly evolving sector. Indeed, the quest for speed and efficiency in sailing races drives engineers to explore innovative solutions. However, residual stresses, often overlooked in analyses, can have a significant impact on the mechanical behavior of these materials. This thesis by Antoine Le Palabe highlights these crucial issues, which deserve particular attention.
The results of this research reveal that the amplitude of residual stresses can reach 30 MPa for a 90° ply. This figure underscores the importance of considering these stresses when sizing composite structures. For example, in the construction of competitive boat hulls, a poor assessment of residual stresses could lead to failures in service, thereby compromising the safety of sailors and the performance of vessels. Past incidents in the world of sailing, where hulls have suffered critical deformations due to design flaws, emphasize the importance of these studies.
Another key point is the fatigue transition value identified at 420 MPa, corresponding to a lifespan of 10^6 cycles. This means that engineers must integrate this data into their models to predict the durability of materials. Understanding the effects of residual stresses thus allows for the optimization of the design and manufacturing of parts, ensuring enhanced performance under real usage conditions. For instance, design teams could use this information to adjust laminate thicknesses or the choice of resins, which could extend the lifespan of vessels while maintaining high performance.
The methodology adopted by Le Palabe, combining experimental protocols and numerical simulations, offers a rigorous approach to analyzing thermoelastic coupling and residual stresses. This approach allows for a better understanding of the interactions between the various factors influencing the behavior of composites, thus paving the way for innovations in the field of sailing. By integrating advanced digital tools, researchers can simulate various scenarios, ranging from calm sea conditions to storms, thereby providing valuable data for designers.
The strategic recommendations arising from this research are clear: it is imperative to integrate the effects of residual stresses in the sizing of composite structures. Furthermore, an energetic approach to establishing more accurate fatigue curves could facilitate the development of higher-performing composites. Engineers and designers must therefore seize these results to design more robust and durable structures, suited to the high demands of competition. This could also involve closer collaboration between researchers and industry professionals to ensure that the latest scientific discoveries are quickly put into practice.
In summary, this thesis significantly contributes to the advancement of knowledge on laminated composites and opens new perspectives for their use in competitive sailing. The issues of safety and performance are more relevant than ever, and it is crucial that industry stakeholders take these advancements into account to remain competitive. In a context where competitive sailing is increasingly subject to strict standards and heightened commercial pressure, the results of this research could become a major asset for teams wishing to stand out. By integrating this new knowledge, the sector can not only improve the safety of vessels but also strengthen the position of competitors on the international stage.
Données clés
- 30 MPa : Amplitude des contraintes résiduelles pour un pli à 90°, soulignant leur impact sur le dimensionnement des structures.
- 420 MPa : Valeur de transition de fatigue, essentielle pour prédire la durabilité des matériaux dans des conditions réelles.
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Sources et accès
Antoine Le Palabe. Effet des contraintes résiduelles sur le comportement de composites stratifiés d’UD carbone/époxy : application au nautisme de compétition. Matériaux. Université de Bretagne Sud, 2023. Français. ⟨NNT : 2023LORIS681⟩. ⟨tel-04870323⟩