Flutter Analysis Of Honeycomb Sandwich Panel With Negative Poisson’s Ratio In Supersonic Flow

Honeycomb sandwich panel with negative Poisson’s ratio is designed by changing the structure of traditional honeycomb sandwich panel.Honeycomb sandwich panel with negative Poisson’s ratio has properties of impact,fracture resistance,energy absorption and vibration isolation which are the properties of negative Poisson’s ratio material,in addition to the advantages of traditional honeycomb sandwich panels.The negative Poisson’s ratio material is benefited to weaken the shock when the supersonic aircraft breaks through the sound barrier.Therefore,the honeycomb sandwich panel with negative Poisson’s ratio can be used to study the aircraft panel.Based on this purpose,the flutter characteristics of the honeycomb sandwich panel with negative Poisson’s ratio in supersonic flow are discussed.First,based on Reddy third-order shear theory,large deflection theory and first-order piston theory,the three-dimensional governing equations of honeycomb sandwich panel are established.Then,the equations are discretized by Galerkin method and the characteristics of flutter of honeycomb sandwich panel is studied deeply by using numerical methods.The influence of various parameters on the critical dynamic pressure and limit-cycle amplitude of the system are discussed,as well as the complex response of the panel under different dynamic pressures.Finally,the flutter response of the panel under the impact of the oblique shock is analyzed.The linear flutter analysis results show that the panel with different parameters have different flutter characteristics.The flutter frequency and the critical dynamic pressure decrease when aspect ratio of the panel increases.Considering the in-plane loads,the critical dynamic pressure and flutter frequency of the panel increase,if the positive in-plane loads increase.The critical dynamic pressure and flutter frequency of the panel decrease,if the negative in-plane pressure increase.Changing the laying direction of the honeycomb core could significantly change the flutter characteristics of the panels.The flutter critical dynamic pressure of the panel can be improved by choosing appropriate parameters.The nonlinear flutter analysis shows that,the amplitude of the limit cycle of the panel increases when the dynamic pressure increase.The critical dynamic pressure of nonlinear flutter analysis is consistent with the results of linear flutter analysis.When not considering the in-plane load and the dynamic pressure is less than the critical dynamic pressure,the vibration of the panel will gradually decay to zero,the panel vibrates periodically with a constant amplitude when the dynamic pressure is greater than the critical dynamic pressure,the limit cycle amplitude and flutter frequency of the panel increase when the dynamic pressure increase.The nonlinear dynamic behavior of the panel becomes more complicated,such as buckling when considering the in-plane load,such as asymmetric simple harmonic periodic motion,multi-period motion and chaotic motion.The flutter with oblique shock impact analysis results show that,the amplitude of the panel flutter reduces,when the shock incident position moves to the tail of the panel,which means that the flutter criticality of the panel increase.Limit cycle amplitude increases when shock angle increases,it means that the presence of the Oblique shock reduces the criticality of the panel flutter.