Flutter Analysis of Laminated Curvilinear-Stiffened Plates

This paper proposes the use of curvilinear stiffeners as a mechanism to control supersonic panel flutter. To account for transverse shear deformation, the plate and stiffeners are modeled according to the first-order shear deformation theory and Timoshenko beam theory, respectively. The Chebyshev polynomials are the basis of the deflection and rotation functions in the Ritz method. The aeroelastic load is formulated according to the first-order high-Mach-number approximation to linear potential flow theory. The minimum potential energy and Hamilton's principle are used to solve the problem. Plots of frequency versus aerodynamic pressure and damping versus aerodynamic pressure are used to determine the critical aerodynamic pressure, and hence to predict flutter of various isotropic and composite, stiffened, and unstiffened plates. The results for the flutter of straight-stiffened plates are validated through comparison with published papers. Several numerical examples are discussed, for which parametric studies for the shape and number of stiffeners and fiber orientation are performed. The flutter mode shapes are also presented. The present study attests that the critical dynamic pressure can be enhanced, and flutter can be successfully suppressed by changing the stiffener's shape and fiber orientation.