Evolutionary-based aeroelastic tailoring of stiffened laminate composite panels in supersonic flow regime

Aircraft skin panels stiffened with attached stiffeners are commonly used in aerospace design. Recent interest on investigations of supersonic flutter of composite panels have concentrated on developments to deal with typical nonlinear aeroelastic responses. Few research on stiffened composite panels is observed in the literature, particularly on aeroelastic tailoring of laminate composites regarding supersonic flutter. This work contributes with an investigation on the aeroelastic tailoring of stiffened laminate composite panels constrained for flutter conditions, thereby allowing design approach for passive flutter avoidance. The finite element method is used to model the panel structural dynamics admitting aerodynamic coupling through the first order piston theory model. The optimization approach is based on a conventional genetic algorithm to maximize the critical flutter dynamic pressure for different arrangements of stiffened laminate composite panels. Stiffened panels were assumed to be restrained with SS1-type boundary condition or an elastic foundation of arbitrary stiffness. Optimized panels for different supersonic flow directions have shown that flutter limits can be elevated by adequate laminate orientation and by altering the flutter mechanism.