Exploration Of Nonlinear Vibration Characteristics Of Flapping Wing Of Flapping-wing Air Vehicle

In order to study nonlinear vibration characteristics of wings of flapping-wing aircraft, flapping wings were simplified as a elastic cantilever rectangular plates, including the establishment of the model, deriving equations, numerical solution, aerodynamic analysis and other aspects and analytical solution of cantilever plates’ vibration was applied to flapping-wing aerodynamic analysis to explore the effect of frequency and amplitude on the aerodynamic characteristics of flapping wings. The main contents are the following aspects:First, the paper introduced theory of Von Karman nonlinear large deflection plate, derived nonlinear vibration equation of cantilever plate taking advantage of elastic mechanics, derived the nonlinear vibration equation of cantilever plate in the transverse harmonic excitation using Galerkin principle, and derived corresponding amplitude frequency response equation through analyzing with improved L-P method. By programming calculation, the nonlinear vibration of cantilever rectangular plates were analyzed. Amplitude-frequency curve and its time course of cantilever rectangular plate resonance were given in different parameters, discussed the affect of load size, aspect ratio, load frequency and other parameters to the characteristics of system nonlinear vibration.Secondly, modal analysis, harmonic analysis and transient analysis were made through Ansys to get natural frequency, amplitude frequency response and displacement waveforms, natural frequency and displacement waveforms were also got by cantilever plate’s experiment of vibration, The phenomenon of experiment were compared and analyzed, the validity and interpretation of theoretical studies on paper were verified.Finally, Two-dimensional model of flapping wing was established by Fluent. Displacement response of analytical solution of flapping wing in different frequency excitation force is applied to Fluent aerodynamic analysis, lift coefficient of flapping wing was calculated at this time. Effect of vibration of cantilever rectangular plates on the aerodynamic characteristics was analyzed by comparing all of the lift coefficients got in different frequencies and amplitudes.