直升机尾传动系统弯曲和弯扭耦合动力学建模与行为研究

The dynamic behavior of helicopter tail drive system plays an important role in overall performance and safety of helicopter. Because of the structure characteristics, such as multi-point supports, flexible connections, elastic supports, as well as the special excitations generated by fuselage and bullet impact, the theories and approaches are required for supporting the dynamic design of helicopter tail drive system. In this project, tail drive system dynamics is researched from two aspects: the bending vibration of the tail horizontal continuous shaft and the coupled bending-torsional vibration of the whole system. Based on the structure traits of tail drive system, analytical methods of the deformation and frictional damping of flexible couplings and elastic supports including bearing-rubber damper-bearing block-tail boom are proposed, and mathematical model with stiffness and damping of Flexible Couplings and Elastic Supports are built under complicated multi-body contact status. Because of the compositional traits of tail drive system, considering the deformation of fuselage and excitations caused by vibration and so on, the dynamic model of shafting with multi-supports, which contains flexible connections and elastic supports, is put forward. Aimed at the characteristics of operating condition even after being attacked by bullets, the helicopter tail drive system dynamic model with transient bullet impact and unexpected unbalance is proposed. Influence laws of vibration caused by main design parameters, maneuvering status and the special excitations are studied. The results of this study can provide design basis of system dynamics for China’s self-developed helicopter tail drive system.

直升机尾传动系统的动力学行为对直升机整体性能和安全性有着重要影响。由于具有多跨轴系、柔性连接、弹性支承等结构特点，以及来自机体、弹击、尾桨等特殊激励，因此直升机尾传动系统动力学设计需要理论和方法支撑。本项目从尾水平轴系的弯曲振动和整个系统的弯扭耦合振动两方面研究尾传动系统动力学。针对尾传动系统轴系连接和支承的特点，研究柔性联轴器、轴承-橡胶弹性元件-轴承座-机体尾桁构成弹性支承的变形和摩擦阻尼分析方法，建立柔性连接和弹性支承的刚度与阻尼数学模型；针对尾传动系统组成特点，提出考虑机体变形和振动等激励、具有柔性连接和弹性支承单元的多跨轴系动力学模型；针对在遭遇弹击之后尾传动系统仍然运转的工况特点，提出弹击瞬态冲击和突加不平衡的直升机尾传动系统动力学模型；研究尾传动系统主要设计参数、机动飞行状态、特殊激励对振动的影响规律。本项目研究成果可为我国自主研制直升机尾传动系统提供动力学设计基础。

直升机尾传动系统的动力学问题极其突出，其动力学行为对直升机整体性能和安全性有着重要影响。在我国自主研制直升机的工程实践中迫切需要尾传动系统动力学理论与方法的支撑。本项目从尾传动轴系的弯曲振动和弯扭耦合振动两方面研究了系统的动力学行为，完成了柔性联轴器动力学模型研究、弹性支承动力学模型研究、使役状态下多跨轴系的弯曲振动研究、使役状态下尾传动系统的弯扭耦合振动研究。具体研究内容如下：. （1）开展了柔性联轴器动力学模型研究。建立了柔性联轴器理论模型，综合有限元仿真和试验验证了理论模型的正确性，通过研究获得了叠片联轴器关键参数对动力学性能的影响规律。. （2）开展了弹性支承轴系动力学建模与分析研究。分别建立了转子、滚动轴承、弹性支座的动力学模型，形成了转子-滚动轴承-支座耦合动力学模型，通过分析获得了基础激励对转子-滚动轴承-支座耦合动力特性影响规律。. （3）开展了使役状态下多跨轴系的弯曲振动研究。通过动态试验和ISIGHT联合仿真，建立了橡胶阻尼环动态刚度和阻尼的力学模型，形成了转子-滚动轴承-叠片联轴器-橡胶阻尼环耦合系统动力学模型，通过研究揭示了关键参数下尾传轴系动力学行为演化机理。. （4）开展了使役状态下尾传动系统的弯扭耦合振动研究。分别建立了机动飞行、弹击损伤、花键摩擦特殊激励下的尾传动系统动力学模型；揭示了机动飞行运动参数对轴系动力学行为影响机理，获得了前飞状态下正、反横滚速度对尾传动轴系的动力学影响规律；研究了花键摩擦自激失稳机理，获得了关键参数下花键摩擦自激行为演化规律；揭示了各弹击参数对系统动力学特性的影响，获得了弹击损伤识别信号特征。

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