Simulative analysis of structural nonlinear flutter characteristics for an actuator-fin system

The flutter characteristics of an actuator-fin system are investigated with structural nonlinearity and dynamics of the hydraulic actuator. The component mode substitution method is used to establish the nonlinear governing equations based on the fundamental dynamic equations of the hydraulic actuator and rocker arm. Numerical simulations are carried out for the different control command and further analysis is conducted when the freeplay angle is changed. The results show that the flutter characteristics significantly depend on the structural nonlinearity as well as the effects of the actuator. Limit cycle oscillations (LCOs) are emerged within linear flutter boundary. The response of the system is related to the velocity of the aircraft. In the nonlinear condition, the amplitude and frequency of control command have also an influence on the flutter characteristics.