Analysis method of structural fatigue damage induced by nonlinear aeroelastic response of control surface

Due to free play, aeroelastic response of a control surface is nonlinear, limited cycle vibration (LCO) occurs on the control surface. Frequencies of LCO are higher than those of fatigue load spectrum of a plane structure, the total vibration cycle number of the control surface with in a plane's lifetime will be more than one hundred thousand times, and the fatigue damage of the control surface induced by LCO has to be taken into account. Thus the relationship between the aeroelastic data of the control surface (free play and velocity) and structural fatigue damage should be established. Here, based on the nonlinear aeroelastic analysis and the structural fatigue analysis, an analysis procedure was developed to study the relationship between LCO of the control surface and structural fatigue damage, and this analysis procedure could guide the setting of free play. In order to illustrate this method, the rotational angle responses of a control surface were obtained with the nonlinear aeroelastic analysis. Based on these responses, the fatigue load spectrum was gained. Finally, the structural fatigue analysis was performed to obtain the relationship between the fatigue damage features of the periphery structures and the nonlinear aeroelastic response of a control surface.