Multidisciplinary wing optimization of commercial aircraft with consideration of static aeroelasticity

This article presents the development and application of a high-fidelity simulation process chain for commercial aircraft wing multidisciplinary optimization. Based upon a parametric CAD model the aerodynamic coefficients of the wing are determined through solving the Reynolds-averaged Navier–Stokes equations within a numerical flow simulation. Structural mass and elastic characteristics of the wing are determined from structural sizing of the wing box for essential load cases by usage of the finite element method. The interactions between the aerodynamic forces and the structural deformation of the elastic wing are taken into account in the process chain by fluid-structure coupling. To reduce the number of design variables, the design task is solved by a two-step approach. To design the inner wing, an optimization of the inner airfoil geometry and the wing twist with the lift-to-drag ratio as objective function has been conducted in the first step. Based on the inboard airfoil of this optimized inner wing, multidisciplinary optimizations of the wing planform have been performed in the second step. These optimizations include the wing twist and thickness distribution in span direction as design parameters but maintain airfoil shapes. A deterministic optimization method has been applied to locate the optimum within the design space. Range and efficiency, in terms of fuel consumption per range and payload, were used as objective functions in the wing planform multidisciplinary optimizations. Two approaches for the determination of the aerodynamic loads for the 2.5-g maneuver load case based on the aerodynamic loads under cruise flight conditions have been investigated. Both approaches have been integrated in the process chain for multidisciplinary wing optimization and have been used for the wing optimization of a long-range aircraft with backward swept wings. The results of the corresponding wing optimizations have been compared with each other