Development of a coupled analysis regarding the rotor/dynamic components of a rotorcraft

This paper presents a combined analysis for the rotor and dynamic components of a rotorcraft. The dynamic components consist of the following elements: a rotor shaft, a drive train, the engine shafts, and an engine and its governor. In this paper, the dynamic components were developed in a modularized fashion and combined with the rotor analysis. The present rotor structural analysis was derived based on the mixed variational formulation of moving beams and combined with finite-state dynamic inflow aerodynamics. A linear mass-spring-damper connection was used for a drive train representation and a simple linear control algorithm was used for an engine governor. To analyze the response of the components, a state-space equation was established based on the torque equilibrium. The present multi-component structural and aerodynamic analysis was solved for by measuring the steady-state trim and time-transient response. Numerical validation was performed using a sample hingeless rotor in a tiltrotor aircraft. The present prediction showed good agreement with CAMRAD II for both the trim analysis and the transient analysis with the trimmed state. And distinctions between the rotor with and without dynamic components were verified. Thus, an accurate framework for the rotor system including the dynamic components was developed, which would be useful during the preliminary design stage of creating a rotorcraft.