FLUTTER OF GEOMETRICALLY-IMPERFECT SHEAR-DEFORMABLE LAMINATED FLAT PANELS USING NON-LINEAR AERODYNAMICS

The dynamic instability resulting from a high-supersonic flow over a simply supported laminated flat panel subjected to uniform in-plane edge compression is studied. The structural model incorporates geometrical non-linearities, transverse shear deformation, and transverse normal stress effects, and satisfies the traction-free condition on both faces of the panel. In-plane edge restraints and small initial geometric imperfections are also considered. Aerodynamic loads based on the third-order piston theory are used and the panel flutter equations are derived via Galerkin's method. The arclength continuation method is used to determine the static equilibrium state whose dynamic stability behavior is subsequently examined. The effects of transverse shear flexibility, aerodynamic non-linearities, initial imperfections and in-plane plate theory generally overpredicts the critical flow speed and compressive load, and a shear deformation theory is required when considering panels that are flexible in transverse shear. When aerodynamic non-linearities are included, multiple flutter speeds may exist. The nature of the flutter boundary for perfect panels is determined by the method of?!multiple scales, and it is seen that the presence of aerodynamic non-linearities could result in the hard flutter phenomenon. Results indicate that non-linear aerodynamics is important for panels that are not sufficiently thin (i.e., panels characterized by a high flutter Mach number).