Vibration reduction characteristics of elastic support dry friction dampers in a dual-rotor system under maneuvering flight

To further study the comprehensive vibration reduction performance of the elastic support dry friction damper, the FE model of dual-rotor system with elastic support dry friction damper under maneuvering flight is established, in which the derivation process of the beam element motion equation is simplified by the energy correspondence and the equivalent node load. The transient dynamic response is solved by $\text{Newmark}-\beta$ and the trajectory tracking method. An evaluation index $D_{RMS}$ for describing the overall vibration reduction effect of the rotor is proposed. The vibration reduction characteristics of the damper in the dual-rotor system as well as those subjected to the maneuvering load are investigated. The results show that: (1) When the motion equation of the disk is extended to the beam element, it is not necessary to substitute the first-order term of the energy about the generalized displacement or the generalized velocity into the Lagrange equation, and the external force term in the kinetic equation can be obtained through the equivalent node load. (2) The effect of the maneuvering load is mainly dominated by the offset of the rotor equilibrium position due to additional inertial force, especially when the concentrated mass occurs in the shaft section with a large support span. (3) Under the optimal installation position and normal force, the damper can reduce the maximum amplitude and overall vibration at the same time. (4) The additional stiffness of the damper can limit the offset of the equilibrium position at the elastic support under the maneuvering flight. The stick state can limit this offset to a minimum, and the optimal normal force of each damper can be obtained from the DC component of the waterfall diagram.