Parametric analysis of inter-blade lag dampers of helicopter rotor

An analytical model is presented for nonlinear helicopter rotor/fuselage coupled dynamics with inter-blade lag dampers. Along with the damper linear properties, numerical simulation and time-domain technology are applied in predictions of rotor/fuselage coupled dynamic instabilities and damper loads in forward flight. The effects of the damper configurations and structural parameters on the system dynamic instabilities and the damper loads are studied, and the significant effects of the damper kinematic couplings are observed. Advantages of kinematic couplings can be utilized by cautiously selecting the damper attachment offset and its build-in angles with rotor hub plane. Compared with a baseline model (which has no damper attachment offset), analytical results show that the regressive lag mode damping can be increased by over 50%, while the damper steady cyclic load amplitude has about 60% decrement for a notional model.