Aeroelastic Optimisation Respecting Stability Derivatives from Unrestrained Trimming

摘要

Top level requirements of major customers of the aircraft manufacturing industries result in technical requirements that tend more and more to highly elastic configurations. Therefore, taking into account aeroelastic and aeroservoelastic requirements in modern aircraft design is a must for the success of today's industrial aircraft projects. Advanced multidisciplinary design analysis and optimisation methods are continuously being developed at Airbus Defence and Space. A new trim solver, which makes use of a coupled aeroelastic formulation together with inertia relief and a mean axis representation was added to the in-house optimisation tool LAGRANGE. As an output, the solver provides aeroelastic stability and control derivatives of an unrestrained aircraft. The unrestrained derivatives are respected as stability constraints which are applied for various optimisation problems and different aircraft configurations in this paper. Structural mass is minimized by varying different properties of aircraft components. Simultaneously aeroelastic derivatives are kept in their ight-physically sensible ranges and structural integrity of the airframe is guaranteed for multiple ight states. The implementation of the system equations in the optimisation problem follows the physical theory of the MSC Nastran aeroelastic solver. The stability coefficients from an aeroelastic analysis are considered in a special formulation as stability constraints. The studies in this paper, show similar benefits for models of generic transport aircraft, fighter and remotely piloted aircraft configurations.