Abstract
In order to reduce the vibration of helicopters, the pendulum absorbers are often adopted. But, most of the papers analyzed its characteristics based on the linear theory and explained focusing on the anti-resonance point. Since the pendulum may vibrate with large amplitude, it is expected that the non-linearity have essential influence on its vibration characteristics. Therefore, we investigated the vibration suppression of the pendulum absorber considering its nonlinearity. In our first report, we proposed a 2-degree-of-freedom (2DOF) model composed of a rigid rotor blade and the pendulum absorber. The blade is excited by giving a sinusoidal deflection at its end. In the second report, we proposed a 3DOF by adding the fuselage. In both of these papers, the blade is considered rigid. The blade is excited by a sinusoidal distributed force. In this paper, a 3DOF model which is composed of a mass corresponding to a rotor mount on the fuselage, a flexible blade, and a pendulum. A periodic distributed force is given on the blade. We show that the vibration is well-suppressed by the pendulum absorbers.
