NONLINEAR PANEL FLUTTER BY FINITE-ELEMENT METHOD

The finite-element method is used here to study nonlinear panel flutter behavior. The governing nonlinear equations are derived from energy considerations, and the nonlinear stretching force is formulated in terms of the transverse displacement alone. Two solution approaches are adopted to solve the nonlinear panel flutter equations. In the first approach, the solution is obtained through the nonlinear vibration mode as the starting point, whereas in the second approach, it is obtained through the linear panel flutter mode as the starting point. The critical dynamic pressure for a given limit cycle amplitude is determined when the flutter frequency values of the first two modes coalesce. Aerodynamic damping is taken into account based on the two available simplifications, and a relation between these two simplifications is brought out. The panel behavior is analyzed from the response parameters of the complex eigenvalues.