The effect of laminate layers and follower force on optimum flutter speed of composite wing

In this article the composite wing aeroelastic instability speed is optimized by genetic algorithm relative to fiber angle for different layers and follower forces. Aircraft wing is modeled as a beam with two degrees of freedom, which is a cantilever, with thrust as a follower force and mass of the engine. For structural modeling of composite wing the layer theory has been used and unsteady flow assuming subsonic and incompressible flow has been used for aerodynamic model in the time domain. Using the assumed mode the wing dynamic equations of the motion have been derived by Lagrange equations. Linear flutter speed according to the eigenvalues of the motion equations has been calculated. The process of flutter speed calculation has been converted to computer code in which the number of layers, angle of fibers in each layer, the mass of the engine, and the thrust are input variables and the flutter speed is its output. Using Genetic Algorithm, optimum flutter speed has been obtained by changing the angle of fibers. Finally, the impact of the number of layers, the mass of the engine, and thrust on optimum flutter speed has been investigated.