一种基于模态的叶片缘板阻尼器减振设计方法

An Efficient Design Method of an Underplatform Damper for Suppression of Blade Vibration in a Given Eigen-Mode

关键词:  转子叶片  缘板阻尼器  减振设计  阻尼比

Key words:  Rotor blade  Underplatform damper  Vibration-reduction design  Damping ratio

摘要:

为了有效解决航空发动机中叶片缘板阻尼器的减振设计问题，在无需开展复杂耗时的非线性响应分析的情况下，提出了一种基于模态的叶片缘板阻尼器减振设计方法。采用半圆形缘板阻尼器的结构形式，根据归一化等效理论，将带有缘板阻尼器的转子叶片简化为以集总参数表示的单自由度模型。引入局部微滑动模型及刚度比例因子，给出了不同干摩擦模型的非线性摩擦力求解方程。针对给定的转子叶片许用振动应力，计算缘板阻尼器的阻尼比特性曲线，通过对比能量法与谐波平衡法的计算结果，验证了所提出方法的可行性及准确性，并获得了阻尼比随相关设计参数的变化规律。对于文中示例，给定许用振动应力幅值为[50MPa]，最佳缘板阻尼器质量约为7.34g，其峰值阻尼比约为0.33%。

Abstract:

To solve the problem of vibration-reduction design for underplatform dampers in aircraft engine， based on the single degree of freedom model， an effective method of vibration-reduction analysis was proposed without the need for conducting complex time-consuming nonlinear response analysis. Using a type of semi-circular damper structure， in the light of the normalized equivalent theory， the rotor blade with underplatform dampers has been simplified to the single degree of freedom model represented by lumped parameters. Introducing the local micro-slip model and stiffness ratio factor， the nonlinear friction force equations were derived for different dry friction models. From the perspective of the vibration stress of the rotor blade， the characteristic curve of damping ratio for underplatform dampers has been calculated. The feasibility and accuracy of the proposed method were verified by comparing the results of energy method and harmonic balance method， and the variation rule of damping ratio with the relevant design parameters was obtained. As for the model in this paper， given that the amplitude of vibration stress is 50MPa， the optimal mass of underplatform damper is about 7.34g， and the peak damping ratio is about 0.33%， providing a reference for the parametric design of dampers.