Aeroelastic Tailoring of Composite Wings with High-Fidelity Aerodynamic Drag and Blending Constraints

This dissertation explores the development of a framework for wing aeroelastic tailoring in the preliminary design phase of aircraft, focusing on weight reduction and aerodynamic efficiency through the use of composite materials. The framework utilizes low-fidelity, fast computational tools to handle numerous load cases, modeling the wing structure with FEM shell elements and aerodynamics with the doublet lattice method (DLM). Composite material properties are optimized using lamination parameters, with structural continuity enforced through blending constraints.

To address the limitations of low-fidelity methods, CFD-based corrections are applied to the DLM for accurate aerodynamic load representation, and a surrogate model is introduced for aerodynamic drag estimation. This model approximates wing deflection efficiently, reducing the need for costly high-fidelity simulations.

The framework, implemented in Nastran, is applied to industrial cases focusing on the impact of blending constraints, dynamic load cases, and multi-objective optimizations balancing weight and drag. Blending constraints result in smoother transitions between wing sections, ultimately producing a light final design, even though there is an initial 5% increase in structural weight due to a reduced design space. Dynamic loads, incorporated through the Equivalent Static Load (ESL) method, have minimal impact on the overall design.

Multi-objective optimization reveals trade-offs between structural weight and aerodynamic drag. Weight minimization favors structures with wash-out behavior, leading to higher drag due to increased angle of attack. Conversely, drag minimization results in stiffer wings with less wash-out. The framework's results align closely with full-order CFD models, validating its effectiveness.