Theoretical Research On The Flutter Passive Control Of Composite Sandwich Panels

Dynamic aeroelasticity in aircraft structures is concerned with the interaction amongaerodynamics, elastic and inertial forces. Flutter is the dynamic instability of aeroelasticstructures induced by unsteady aerodynamic loadings. Supersonic panel flutter is a key designconsideration for high-speed aerospace vehicles. This thesis studies the flutter of compositesandwich panels in the supersonic flow. The conclusions may provide some references for theanti-flutter design and the passive control of the aircraft.Firstly, the governing equation of composite sandwich panel flutter consideringgeometric nonlinearity due to large deformation is derived by the generalized Hamilton’sprinciple. Then both the linear and nonlinear panel flutter characteristics are analyzed. Theemphasis of the study is the influence law that the dynamic pressure and damping acting onthe flutter characteristics.The contents of this thesis are as follows:1) The research achievements, mechanism and analysis method of panel flutter aresummarized comprehensively.2) The governing equation of composite sandwich panel flutter is derived by thegeneralized Hamilton’s principle based on Hoff sandwich panel hypothesis and Von-Karmangeometric large deformation theory. The quasi-steady piston theory of supersonic flow isemployed for the aerodynamic pressure.3) The governing equation neglecting nonlinear term is transformed into a set ofordinary differential equations via the Galerkin approach. First-order state equations areafterwards obtained and solved by means of a standard eigenvalue calculation. The dynamicinstability of sandwich panels is predicted by the feature of characteristic roots. The effects ofdiscrete order number and damping on the critical point of flutter are discussed.4) The nonlinear governing equation based on Kelvin-Voigt model is slovednumerically via four order Runge-Kutta method. Nonlinear dynamic response is analysedunder different dynamic pressure.