Nonlinear flutter analysis of composite panels

Nonlinear panel flutter is an interesting subject of fluid–structure interaction. In this paper, nonlinear flutter characteristics of curved composite panels are studied in very low supersonic flow. The composite panel with geometric nonlinearity is modeled by a nonlinear finite element method; and the responses are computed by the nonlinear Newmark algorithm. An unsteady aerodynamic solver, which contains a flux splitting scheme and dual time marching technology, is employed in calculating the unsteady pressure of the motion of the panel. Based on a half-step staggered coupled solution, the aeroelastic responses of two composite panels with different radius of R = 5 and R = 2.5 are computed and compared with each other at different dynamic pressure for Ma = 1.05. The nonlinear flutter characteristics comprising limited cycle oscillations and chaos are analyzed and discussed.

Nonlinear Panel Flutter of Composite Sandwich Plates with Thermal Effect

ABSTRACTBy considering the total transverse displacement of a sandwich plate as the sum of the displacement due to bending of the plate and that due to shear deformation of the core, a high precision higher order triangular plate element is developed for the nonlinear panel flutter analysis of thermally buckled sandwich plates. Von Karman large deformation assumptions and quasi-steady aerodynamic theory are employed for the analysis. Newmark numerical time integration method is applied to solve the nonlinear governing equations in time domain. Results show that temperature will increase both the maximum displacement and motion speed of the plate. But the maximum displacement and velocity of the plate will not vary much with the aerodynamic pressure. Buckle pattern change phenomenon occurred in some specific case will increase the flutter boundary and change the flutter motion type of the plate. Temperature gradient increases the overall stiffness of the plate, which in turn stabilizes the sandwich panel and increases the flutter boundary of the plate.