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Session: Aeroelastic optimisation 2
Session starts: Tuesday 18 June, 11:00
Presentation starts: 12:00
Room: Room 1.1

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Hammad Rahman (Delft University of Technology)

Abstract:
The aviation industry is striving to create high-performance aircraft that consume less fuel. This involves using composite materials to reduce weight and implementing methods to alleviate aeroelastic loads. The stiffness of the wing, determined by the layout and sizing of its internal structure, is crucial. While traditional manufacturing constraints have limited layout configurations, recent advancements have enabled more complex layouts. To fully utilize the synergies between layout and sizing design variables, simultaneous optimization is essential. However, previous optimization studies often use gradient-free methods, which are easier to implement but restrict the design space due to a limited number of design variables. This limits the potential improvement that optimization can bring. This paper presents an innovative design strategy that simultaneously optimizes layout and size design variables using a gradient-based method. It employs a CAD modelling tool to parameterize the geometry. This CAD-based parameterization offers two advantages. First, it implicitly applies geometric constraints to ensure the perturbed wingbox layout conforms to the wing’s OML, eliminating the need for additional constraints on the grid point coordinates. Second, a link with the CAD model is maintained throughout the optimization process, as the same design variables are controlled by the optimizer. This eliminates the need for an additional step of converting the optimal design back to the CAD model. Instead of mesh morphing, a re-meshing strategy is employed. The sensitivities of the response with respect to both layout and size design variables are achieved through a semi-analytical method, which is a faster approach for calculating gradients compared to finite difference schemes. The CRM wing under aeroelastic constraints has been used as a design model. The design variables include the thickness of the design regions, as well as the individual rib and stiffener location and orientation. Gust loads are included using the Equivalent Static Load Method. The primary focus is to investigate the potential benefits of simultaneous layout and size optimization in alleviating the static and dynamic loads on the wing. These investigations are expected to provide valuable insights and additional ways to locally tailor the structure.