非线性叶间黏弹减摆器对直升机空中共振的影响分析

 建立带非线性叶间黏弹减摆器的直升机旋翼/机体耦合动稳定性分析模型。与全机飞行力学平衡计算相结合，旋翼/机体耦合动稳定性分析模型考虑前飞状态桨叶变距操纵、机体姿态角和桨毂纵向安装角。针对具有非线性特性的叶间黏弹减摆器，采用基于复模量的非线性VKS改进模型、Simulink时域仿真和多桨叶坐标变换等效阻尼识别法分析直升机悬停、前飞状态下旋翼/机体耦合动稳定性及减摆器双频动幅值，并就减摆器布局、全机总重以及前飞速度对桨叶摆振后退型模态阻尼的影响进行分析。结果表明：由悬停到前飞直升机动稳定性一般均下降，一定速度后又上升；加上减摆器能消除前飞不稳定区；叶间黏弹减摆器抬头连接能提高模态阻尼。

Influence Analysis of Helicopter Air Resonance with Nonlinear Interblade Viscoelastic Dampers

An analytical model is developed for helicopter rotor/fuselage coupled dynamic stability with interblade nonlinear viscoelastic dampers.Coupled with the calculation of helicopter equilibrium in the flight dynamics,the analytical model considers the factors as blade torsion manipulation,fuselage pose angle and hub longitudinal install angle.Along with the blade viscoelastic damper nonlinear properties, an improved nonlinear VKS model based on complex modulus, Simulink emulation in time-domain and equivalent damping identification based on numerical multi-blade coordinate transformation are applied in predictions of rotor/fuselage coupled dynamic stabilities in hover and forward flight, and the damper dynamic amplitude in the condition of dual-frequency.Effects of the damper configurations, gross weight and flight velocity on the regressive lag modal damping are studied.The results demonstrate that the helicopter dynamics stabilities decline in the starting time to forward fly, but ascend after specific velocity, and that the air resonance could be avoided with interblade viscoelastic dampers added and the regressive lag modal damping could be increased by lead-up joint of the damper.