The Aeroelastic Characteristic of a Wing with Preload Asymmetry Freeplay

Nonlinearitiesin designing aircraft are inevitable. It is necessary to investigate the effects of them on the dynamic response. The aeroelastic dynamic model with freeplay nonlinearity in pitch degree of freedom is established with the Theodorsenaerodynamic model. The harmonic balancemethod is employed to obtain the flutter boundary. Then the nonlinear responses and the stability characteristic are studied by using the time marching aeroelastic method. The effects of the initial displacement in pitch degree of freedom and the gap size on the LCO characteristics are investigated. Results show that the appearance of the LCO depends on the initial condition and the flow speed. The velocity range for the existence of the LCO and the LCO amplitude are related to the freeplay gap.