翼吊发动机安装结构等效建模及其隔振设计

Equivalent modeling and vibration isolation design of wing-mounted engine structure

为了研究翼吊发动机安装结构隔振特性并优化其隔振器设计,建立了发动机安装节-吊架-机翼结构理论分析及有限元模型.利用有限元方法进行了模态验证并分析了安装结构的隔振特性.进行发动机3种典型工况下的结构动响应分析确定了振动传递的主路径.基于振动传递路径法研究了隔振器参数和安装位置对安装系统隔振性能的影响规律.结果表明:振动载荷经安装结构后低压转子转频和高压转子转频峰值响应分别降低22.03%和14.65%.低压转子转频振动传递主路径为发动机-前安装节-吊架-机翼,高压转子转频为发动机-后安装节-上连杆-机翼.通过合理设置隔振器位置可以使安装系统隔振率达到50.41%,隔振器的频率比为5和阻尼比为0.25时安装系统隔振率可达70.67%.为了优化整个发动机安装系统的隔振效果,设计隔振器时必须选取合适的安装位置和参数.

In order to research the vibration isolation characteristics and optimize isolator design of wing-mounted engine mounting structure, the theoretical analysis model and finite element model of engine mounting joint-pylon-wing structure were built. The modal verification and vibration isolation characteristic of the mounting structure was analyzed using finite element method. The dynamic response and vibration transmission main path under three typical load spectra was analyzed. The influence of isolator parameters and position on the engine mounting system isolation performance was also analyzed based on the vibration transmission path method. The results show that the peak response of vibration load under rotation frequency of low pressure rotor, rotation frequency of high pressure rotor can reduce to 22.03% and 14.65% by the mounting structure; the vibration transmission main path un- der rotation frequency of low pressure rotor is the engine-former engine mounting joint-py- lon-wing while under rotation frequency of high pressure rotor is the engine-latter engine mounting joint-upper connection rod-wing. The vibration isolation rate of mounting system can reach 50. 41% by reasonably setting the position of the vibration isolator, and even reach 70.67 % when the frequency ratio of isolator is 5 and the damping ratio is 0.25. The installation position and the parameters of isolator must be appropriately selected to acquire optimal vibration isolation effect of the entire engine mounting system.