Multibody Simulation of Low Frequency Aeroelastic Wing Loads

Aircraft wings are frequently fitted with outboard equipment, either with external fuel tanks to augment the mission range, research or military aircraft with various sensors for scientific or reconnaissance missions, and of course combat aircraft with missiles or bombs. These external devices not only influence the aerodynamics of the wing, they also change considerably the structural behavior of the wing and the flight mechanics. The release of such equipment leads to peak loads on the wings which can be rather high, especially if the aircraft is in a special flight condition, e.g. a high-g turn. To enable a realistic assessment of the aeroelastic phenomena of aircraft, a simultaneous application of computational fluid dynamics (CFD), computational structural mechanics and flight mechanics has thus to be performed. The combination of CFD and elastic multibody simulation with its large number of interfaces to other disciplines systems is well suited for the simulation of a range of aircraft applications, especially for aircraft ground dynamics and store separation. The article presents methods to couple aerodynamics, structural mechanics and flight mechanics in the time domain based on multibody dynamics in a virtual design environment. The applied programs and the coupling methods are presented. Advantages and limits of using multibody simulation as compared to the direct use of FEA methods for the representation of structural dynamics are discussed