Nonlinear vibration analysis of a control fin with freeplay nonlinearity

In order to establish a nonlinear dynamic model of the aircraft-control fin, the fixed interface component mode synthesis method (C-B method) was used to divide the overall structure of the aircraft into two linear substructures, fuselage and control fin, with the DOFs corresponding to the nonlinear control stiffness element in the interface. The modal analysis of each substructure is carried out to obtain its natural modal characteristics. By using the force equilibrium and displacement coordination between the substructures, and considering the nonlinear loaddisplacement relation between the substructures, the low-order modal characteristics of the substructures are synthesized to obtain the nonlinear dynamic characteristics of the whole structure. The FEM software for component mode substitution of all-moved rudder is developed, which is used to simulate the structural dynamic response of the reduced-order control fin model in time domain.