Development of an Aero-Structural Aircraft Fuselage Optimization Methodology Considering Internal Layout

Fuselage drag and structural weight strongly influence aircraft performance. Accurate prediction of these quantities requires consideration of the internal layout, which defines the spatial constraints of the outer mold line. Modern eVTOL and eSTOL configurations have large freedom in internal layout because they contain diverse components and mission equipment. However, prior studies have not proposed a combined internal layout, aerodynamic and structural optimization methodology. As a result, the influence of layout variations on fuselage design has remained unclear. This study presents an integrated methodology that connects internal layout design with high fidelity aerodynamic and structural optimization. A greedy algorithm and a genetic algorithm are used to generate feasible internal layouts under placement constraints. Aerodynamic shape optimization is performed with an adjoint based solver that uses an ellipsoidal initial geometry enclosing the layout, and structural optimization is carried out by linking internal component masses to the fuselage structure through an RBE3 based modeling approach. These steps form a complete fuselage design process that incorporates internal layout aerodynamic shape and structural configurations. The methodology is applied to a lift plus cruise eVTOL. Layout driven designs show reductions in drag and structural weight of up to 13.3% and 13.2% relative to designs that use a baseline layout. The result of the study demonstrates the strong influence of internal layout on fuselage design and highlight the importance of layout informed aerodynamic and structural optimization.