Active and Passive Suppressions of Nonlinear Panel Flutter Using Finite Element Method
Active and passive suppression schemes for nonlinear flutter of composite panel are investigated using lead zirconate titanate (PZT). First, in the active control method, the optimal controller based on the linear optimal control theory is designed for flutter suppression of the panel. Second, a new approach, a passive suppression scheme, is suggested for suppression of the nonlinear panel flutter. A passive damping technology, using one shunt circuit and two independent shunt circuits, which is believed to be a more robust suppression system in practical operation, is proposed. This approach requires very little or no electrical power. In this passive method, the piezoelectric shunt circuit, which consists of resistor-inductor-capacitor elements in series, is applied. In both methods, a finite element formulation for composite plates with PZT layers is derived using classical laminated plate theory. The adopted aerodynamic theory is based on the quasi-steady piston theory, and the von Karman nonlinear strain-displacement relation is used. A modal reduction technique is used to reduce the number of modes involved and to simplify the nonlinearity of the model. Numerical results, which are based on the reduced nonlinear modal equations of active and passive suppression for nonlinear panel flutter are presented in the time domain using the Newmark-β method. To achieve the best suppression effect, optimal shape and location of the piezoceramic (PZT) patches are determined by using genetic algorithms. The results clearly demonstrate that the passive damping scheme as well as active control can effectively attenuate the flutter.