Nonlinear Aeroelastic Trim of Very Flexible Aircraft Described by Detailed Models

This Paper presents an efficient algorithm for the nonlinear aeroelastic trim analysis of very flexible aircraft described by detailed models. The algorithm is based on a novel inertia relief technique for large displacements and is applicable to fluid–structure iteration frameworks coupling generic structural and aerodynamic solvers, including high-fidelity commercial solvers. The methodology is tested on a low-order model of the University of Michigan’s X-HALE experimental vehicle in order to compare to reference results for a typical steady rectilinear flight condition. Nonlinear aeroelastic trim analyses conducted at different flight speeds show that the proposed approach gives a smooth and fast convergence to the trim solution, which makes it suitable for high-fidelity aeroelastic design of very flexible aircraft.