Research On Thermal Flutter And Fatigue Performance Of Supersonic Panel

The study of flutter originated from early flight accidents,and it is an aeroelastic phenomenon that aerodynamic,elastic and inertial forces work together.As the development of the aircraft enters the supersonic and hypersonic stages,the phenomenon of aerodynamic heating cannot be ignored,and the research on the thermal flutter of the panel came into being.Thermal flutter analysis of panel involves flutter boundary problems and nonlinear response problems.Due to the existence of vibration,fatigue damage can be caused.The study of panel flutter fatigue cannot be ignored.Based on the transverse vibration equation of the two-dimensional panel,considering the influence of aerodynamics and aerodynamic heat on the aircraft panel,a first-order linear piston theory is used to establish the partial differential equation of thermal flutter of the two-dimensional panel.The thermal flutter characteristics are studied from two aspects of linear and nonlinear.The thermal flutter of the panel will cause the cumulative fatigue damage of the structure.The Heywood fatigue calculation model is introduced to study the flutter fatigue life.First,the critical buckling temperature of a two-dimensional panel is obtained based on the classical linear buckling theory.The numerical analysis method is used to study the thermal flutter linear vibration problem.The flutter stability equations are obtained for the simple and fixed boundary conditions.Based on the trial and error method and frequency coincidence theory,the critical dynamic pressure of flutter under different temperature conditions is obtained,and the flutter boundary under the influence of temperature is obtained.The research shows that the temperature effect reduces the critical dynamic pressure of flutter.In addition,the influence of the aerodynamic damping term on the thermal flutter of the panel can be ignored.Second,based on the large deformation of the structure,considering the combined effects of geometric nonlinearity and aerodynamic heating,small disturbances are introduced,and the Galerkin method is used to calculate the vibration equations including static deflection and small disturbance deflection,respectively.Considering the influence of two kinds of boundary conditions,the flutter boundary under different temperature conditions is obtained.In the vibration equation containing small perturbation deflection,the influence ofaerodynamic damping on the thermal flutter of nonlinear panel is considered again.The research shows that the effect of aerodynamic damping can also be ignored.Finally,the fatigue performance of thermal flutter of panel is studied.The finite-difference method is used to analyze the thermal flutter of panel.The linear fatigue cumulative damage theory and Heywood method were used to establish the relationship between the flow pressure and fatigue life.The research in this paper provides a useful reference for the design of supersonic wall panels.