Investigation Of Panel Flutter For Laminates With Thermal Effect

Panel flutter is a classical supersonic aeroelastic phenomenon that is usually accompanied by temperature elevation on the outer skin of high-speed aerospace vehicles. This phenomenon always leads to fatigue failure of the skin panels and has harmful influence on the flight perfermance and even flight safety. The aim of this thesis is to analyze the panel flutter mechanism and establish a mechanical model for panel flutter analysis and this work is the basis of panel flutter control studies.At first, the finite element formulation is presented to determine the flutter characteristics of laminated panels at elevated temperature. Then both the linear and nonlinear panel flutter characteristics are analyzed. The panel flutter boundaries are finally determined and the effect of temperature, airflow speed, etc, on the panel flutter characteristics is analyzed.The contents of this thesis are as follows:(1) . The research activities of panel flutter are summarized comprehensively. The mechanism of panel flutter and the analysis method of panel flutter are described in details.(2) . The mechanical model of panel flutter considering thermal effect is established by the use of von Karman large deflection strain-displacement formulations, quasi-steady first-order piston theory aerodynamics and quasi-steady thermal stress theory.(3 ) . The finite element equation for linear and nonlinear panel flutter analysis using the triangular three nodal Mindlin element (MIN3) which considers the first order shear strain in the plate is formulated. With this kind of element, panel flutter analysis can be performed not only for thin plates but for the middle-thickness laminates.(4) . The Newmark method is used to solve the panel flutter equations in time domain. The linear flutter boundaries are determined and the effect of temperature on flutter boundaries is analyzed.( 5 ) . The nonlinear panel flutter equations are also solved in time domain. The limit cycle flutter characteristics of nonlinear panel flutter are investigated and the effect of temperature and airflow speed on the nonlinear panel flutter characteristics is studied.