Design Of Continuous Trailing-Edge Flap Based On MFC And Analysis Of Influence On Rotor Vibration Loads

In this paper,a thermal-elastic analogy method for mechanical analysis of MFC was established,and the feasibility of this method was verified by piezoelectric deformatiom experiment of cantilever beam with MFC(Macro Fiber Composite).A blade section with a continuous trailing-edge flap was designed based on the NACA23012 airfoil with MFC as actuating material.In order to accurately calculate the influence of the deflection of continuous trailing-edge flap on aerodynamics,a fluid-solid interaction analysis method was established.The analysis results show that the continuous trailing-edge flaps can deflect effectively at a wide range of angle of attack and Mach number,and generate considerable additional aerodynamic lift and moment while maintaining a relatively low level of resistance.To improve the simulation efficiency of vibration loads control,the aerodynamic analysis model of continuous trailing-edge flap was established based on radial basis function.An accurate aeroelastic model of smart rotor was built for study the influence of continuous trailing-edge flap on the rotor vibration loads.The accuracy of the model was verified by calculating profile loads of SA349/2 and BO105 helicopter blade.A series of phase sweep simulation analysis for fourth-order vibration loads of BO105 helicopter hub was carried out respectively in different frequencies and different amplitudes of the flap deflection.The results show that continuous trailing-edge flap has potential to control rotor's vibration load.With frequency,amplitude and phase of flap deflection as variables and the fourth-order harmonic components of hub loads as targets,the optimization objective function of vibration loads was established.The optimal deflection law of the continuous trailing-edge flap and the corresponding vibration loads under different optimization objectives were solved.The results show that regular deflection of continuous trailing-edge flap can effectively control rotor vibration loads.