含裂纹离心压缩机叶轮结构的振动局部化

Vibration localization of cracked impellers of centrifugal compressors

针对离心压缩机在复杂运行工况下的失谐与裂纹问题,研究裂纹与失谐对叶轮结构振动响应和振动局部化的影响规律。首先,采用三维有限元模型建立具有复杂几何形状的叶轮结构的定量分析模型,并通过在裂纹界面上定义接触的形式模拟裂纹的呼吸效应。其次,通过采用混合界面模态综合法对系统自由度进行缩减,以解决了采用三维有限元模型分析非线性系统动态响应时所存在的计算量大和收敛困难的问题。最终,采用Monte Carlo方法对含裂纹的失谐叶轮结构进行统计分析,研究随机失谐和裂纹故障对叶轮结构振动局部化的影响规律。结果表明裂纹和失谐都会对结构的振动响应产生显著的影响,并会导致振动能量的集中和振动局部化现象。

With regard to the mistuning and crack problems of centrifugal impellers operating under complex conditions, the effects of crack and mistuning on the forced response and vibration localization of centrifugal impellers were investigated. 3D finite element models of impellers were established for the dynamic analysis of complex impellers. Several contact pairs were defined on the crack surfaces to simulate the nonlinear crack breathing effects. Then, the hybrid interface component mode synthesis method was employed to reduce the number of degrees of freedom of the system. The method can reply the chanllenges of huge computation requirment and convergence in the dynamic response computation of nonlinear system by using directly 3D finite element models. The Monte Carlo method was employed to statistically study the effects of random mistuning and crack fault on the vibration localization of impellers. The results show that both the crack and mistuning will significantly affect the dynamic response of impellers and will lead to the localization of energy on certain blades. © 2017, Editorial Office of Journal of Vibration and Shock. All right reserved.