Flutter Analysis For A Wing System Including Engine’s Gyroscopic Effect

Large transport aircrafts and civil aircrafts tend to adopt an Under-the-Wing engine mount configuration. Along with development of new advanced technologies, for instance, composite materials have been coming into application in the process of aircraft design due to its many inherent traits, modern aircrafts are becoming lighter and more flexible, with lager wing aspect ratio.As a result, the aeroelasticity become a inevitable and crucial problem in the aerodynamic analysis. Besides, in general, aircraft engine makes up roughly ten percentage of the total weight of the aircraft. Therefore, it is necessary to include engine rotor’s gyroscopic effect for more accurate analysis when dealing with the aeroelastic problem, especially the aircraft flutter.In order to study the gyroscopic effects of the engine on the engine-wing system’s flutter Characteristics,this paper carried on finite element analysis of an engine-straight wing model, calculated the kinetic energy and potential energy of the system, calculated the unsteady aerodynamic force with the doublet lattice method,and used Matlab, derived the flutter equation on matrix form according to Hamilton variational principle, converted the unsteady aerodynamic force from frequency domain into time domain by minimum-state method, established the system’s state-space equation, obtained the flutter characteristics under different engine speed by root locus method. The results showed that:in the particular connection stiffness, with the increase of engine speed,the flutter speed gradually decreased,and then gradually increased when the engine speed exceeds a certain value.Then, NASTRAN was used to establish the finite element model and aerodynamic model of a engine-wing system. The system’s Campell curve were obtained through the complex modal analysis method; solution sequence SOL145 was used to obtain the flutter characteristics under different engine speed by p-k method.