This paper describes a modified structural dynamics model for aeroelastic analysis of high-aspect-ratio wings undergoing large deformation behavior. To gain this aim, a moderate deflection beam model is modified with some important large deflection terms and then coupled with a state space unsteady aerodynamics model. Finite element method is used to discretize the equations of motion. A dynamic perturbation equation about a nonlinear static equilibrium is applied to determine the flutter boundary. The obtained results show good agreement in comparison with the other existing data such as high-altitude long-endurance (HALE) wing and Goland wing. It is found that the present aeroelastic tool have a good agreement in comparison with valid researches and also considering the effect of the geometric structural nonlinearity and higher order nonlinear terms on the flutter boundary determination is very significant. تفاصيل المقالة