Increase of Flutter Speed using Variable Stiffness Concepts in Composite Plates

This contribution is devoted to seek the potential of variablestiffness concept in composite laminates subjected to a flowpassing over their top surface. In practice, this problemoccurs in the wings of jet fighters or space shuttles, wherethe airspeed may reach up to five times the speed of sound,or Mach 5. The theory used here to model the aerodynamicforce (pressure), namely Piston theory, is generally valid forlow supersonic Mach numbers. The structural model of thelaminate is based on the third-order shear deformationtheory. The solution of the eigenvalue problem of thecoupled structural and aerodynamic models gives theflutter speed. Considering that flutter is a dynamicinstability of the laminate, the vibrations due toaerodynamic forces before this speed can be regarded asdynamically stable.