The nonlinear government equations of the flutter problem of high-aspect-ratio flexible composite wing were derived from the most general aeroelasticequations with wing′s structure geometrical and aerodynamic nonlinearity being considered. Then the gradients of flutter speed and frequency of wing with respect to the design variables were deduced with analytical method. The influence of the composite wing′s configuration and ply angle on the flutter speed was revealed. It was concluded that the composite structure configuration that caused negative bending twist coupling was beneficial to wing′s flutter performances. An optimization design of a high-aspect-ratio flexible composite wing model was done with the flutter speed as object function and the composite plies as design variables. The best configuration and plies were obtained and the results obtained with analytical gradients of this paper and numerical difference gradients were compared at the same time.
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