A study on the aero-elastic flutter of stiffened laminated composite panel in the supersonic flow

The flutter of a stiffened laminate composite panel subjected to nonlinear aerodynamic force is investigated by means of a new analytical model in the present study. The von-Karman large deflection plate theory is used to account for the geometrical nonlinearity of the stiffened composite panel, and the third order piston theory is employed to estimate the nonlinear aerodynamic pressure induced by the supersonic airflow. The interaction between the panel and the stiffener is considered to be a pair of acting force and reacting force. According to the Hamilton principle and the Euler-Bernoulli beam theory, the coupled partial differential governing equations of the panel and the stiffener are established. On the basis of deformation compatibility between the panel and the stiffener, the assumption mode shapes of the panel are introduced into the dynamic partial differential governing equations of the stiffener to calculate the acting/reacting force between the panel and the stiffener. When the expression of the acting/reacting force is substituted into the dynamic differential governing equations of the panel, the fourth-order Runge-Kutta numerical integration method is employed to simulate the dynamic response of the stiffened panel. The effects of various parameters, such as the stiffening scheme and the geometric dimension of the stiffener, on the critical flutter dynamic pressure and the amplitude of the transverse vibration of the panel are studied in details. The simulation indicates that the critical flutter dynamic pressure can be greatly enhanced by introducing a proper stiffening scheme.