Static and Dynamic Aeroelastic Validation of a Flexible Forward Swept Composite Wing

Abstract

An aeroelastically tailored, forward swept composite wing was designed, manufactured, and tested at DLR. One of the goals was the determination of a siffness distribution that maximizes the deflection and minimizes the twist of the wing under high aerodynamic loading. The design of the wing involved a stiffness-based continuous optimization process combined with a discrete stacking sequence optimization using blended laminates. Steady and dynamic aeroelastic tests were performed in a low-speed wind tunnel, where the deformations of the wing and loads were measured. This paper describes the approaches applied to the numerical simulation of the wing and presents comparisons of simulation results to experimental data. The test cases and validations comprise three parts: Static coupling with tip displacements up to 20%, unsteady structural dynamics without aerodynamic forces, and unsteady aeroelasticity. For the unsteady test cases, dynamic effects were provoked by excitation of the wing root in a pitch degree of freedom. The numerical simulations used methods of different fidelity. Geometrically linear and nonlinear structural methods are applied, and for the aeroelastic tests combined with a vortex-lattice method. Good agreement between experiment and simulation was obtained for both the steady and unsteady test cases.