不同粘弹减摆器连接的直升机地面共振分析

Analysis of ground resonance for helicopters with different elastomeric lag damper connections

建立了粘弹减摆器不同连接形式时的旋翼/机体耦合动稳定性分析模型。旋翼/机体耦合动力学模型考虑了非定常空气动力和桨叶挥舞/摆振运动耦合。通过机体当量模型向机体瞬时转心的转换来计入地面运转时机体的滚转和俯仰运动。采用基于复模量的非线性VKS改进模型,建立叶间粘弹减摆器和普通连接粘弹减摆器的小扰动力矩方程。采用特征分析法计算了两种减摆器连接形式的直升机地面共振稳定性。工程实例分析结果表明,本文方法具有物理概念清晰、运用方便的特点。

An analytical model is developed for the dynamic stability analysis of helicopter rotor/fuselage coupled systems with general connections or inter-blade connections for the nonlinear elastomeric lag dampers. Within this analytical model, the factors as unsteady aerodynamic and blade flap/lead-lag coupled motion are both considered. Via a convert from the fuselage equivalent model into the fuselage instantaneous wheel axis, the fuselage roll and the pitch motion are both involved. Through an application of the improved nonlinear VKS model based on complex modulus, /or the cases of general connections and inter-blade connections for the nonlinear elastomeric lag dampers, the small disturbance momental equation is given. The method of eigenvalue analysis is used to investigate the ground resonance stability of the helicopter rotor/body coupled system with two connections of dampers. The results of engineering examples show that the method possesses a clear physical conception and is convenient for use.