直升机旋翼非线性液压减摆器几何耦合及参数影响分析

Analysis of Kinematics and Parameters for a Nonlinear Hydraulic Damper of Helicopter Rotor

为研究几何耦合与设计参数对非线性液压减摆器等效阻尼的影响 ,建立了直升机前飞时 ,计入几何耦合的旋翼液压减摆器的分析模型 ,根据桨叶与减摆器之间的关系和减摆器力 -速度曲线 ,导出了桨叶的摆振运动方程。用 4阶龙格 -库塔法对减摆器轴向速度在时域内的响应进行了计算 ;用能量平衡的原理计算了非线性液压减摆器的等效线性阻尼 ;计算并分析了几种典型的几何耦合形式、减摆器的安装形式和设计参数对轴向速度和等效阻尼的影响。结果表明 ,前飞时变距几何耦合将使液压减摆器的有效阻尼大幅度下降 ;通过改进减摆器的安装型式、选择合理的几何参数可以显著降低轴向速度 ,提高等效线性阻尼。

In order to investigate the effect of kinematics and parameters of nonlinear hydraulic damper on equivalent linear damping, a analytical model of helicopter rotor damper, accounting for kinematic couplings, is presented in forward flight. A blade lead lag differential equation is derived in terms of blade damper relations and damper force velocity curve. Four ordered Runge Kutta numerical method is applied to calculate damper axial velocity in time domain for different cases of kinematic couplings, and equivalent linear damping is obtained from energy balance method. The effects of geometric arrangements on the damper axial velocities and the magnitudes of equivalent linear damping are also analyzed. Results demonstrate that the damper axial velocity could be reduced and equivalent linear damping increased through modifications of damper geometric arrangement and reasonable choices of structural parameters.