NONPERIODIC FLUTTER OF A BUCKLED COMPOSITE PANEL

The nonlinear vibrations of a composite panel subjected to uniform edg e compression and a high-supersonic coplanar flow is analysed. Third-o rder piston theory aerodynamics is used and the. effects of in-plane e dge restraints, small initial geometric imperfections, transverse shea r deformation, and transverse normal stress are considered in the stru ctural model. Periodic solutions and their bifurcations are determined using a predictor-corrector type Shooting Technique, in conjunction w ith the Arclength Continuation Method for the static state. It is demo nstrated that third-order aerodynamic nonlinearities are destabilizing , and hard flutter oscillations (both periodic and quasiperiodic) of t he buckled panel are obtained. Furthermore, chaotic motions of an unco mpressed panel, as well as a buckled-chaotic transition, and chaos via period-doubling are possible, and the associated Lyapunov exponents a re computed. A coexistence of the buckled state with flutter motion ma y also occur. Results indicate that edge restraints parallel to the fl ow do not significantly affect the immediate postcritical response, an d that a higher-order shear deformation theory is required for a moder ately thick/flexible-in-transverse-shear composite panel.