液弹阻尼器动力学特性对直升机地面共振的影响分析

基于汉密尔顿原理,根据直升机旋翼液弹阻尼器的非线性动力学模型和等效线化模型,分别建立了带非线性和线性液弹阻尼器的直升机旋翼/机体耦合系统动力学模型;并对直升机的地面共振稳定性进行了数值模拟,分析了液弹阻尼器动力学特性对直升机地面共振的影响。结果表明,液弹阻尼器的存在增加了桨叶摆振后退型模态阻尼,提高了直升机地面共振稳定性。采用线化模型计算方便,计算结果能基本反映液弹阻尼器对桨叶摆振后退型模态的影响变化趋势;但模态耦合区位置和峰值阻尼的确定不够准确;而非线性模型则能准确描述液弹阻尼器的动力学特性和直升机旋翼/机体耦合系统稳定性的变化规律,精度较高。

Influence Analysis of Dynamic Characteristics of Fluidlastic Damper on Helicopter Ground Resonance

Based on the Hamilton principle, the dynamic model of helicopter rotor/fuselage coupled system with linear and nonlinear fluidlastic damper is established, respectively, according to the nonlinear dynamic model and linear equivalent model of fluidlastic damper for helicopter rotor. The numerical simulation is carried for the ground resonance stability of helicopters and the influence of dynamic characteristics for fluidlastic dampers on the ground resonance is analyzed. The results show that the regressive lag modal damping of blade is enhanced and the ground resonance stability of helicopters is improved due to the presence of fluidlastic dampers. The convenient calculation results with linear model can basically reflect the effect of fluidlastic damper on the regressive lag mode,although the values for the position of mode coupled region and damping amplitude are insufficiently precise. However, the dynamic characteristics of fluidlastic damper and the change law of the stability for helicopter rotor/fuselage coupled system can be both described by the nonlinear model with much higher precision.