刚度随机失谐叶盘结构概率模态特性分析

Probability characteristics of vibratory mode of bladed disk assemblies with random stiffness mistuning

基于典型叶盘结构的集中参数模型和Monte Carlo数值计算,分析了刚度随机失谐叶盘结构的概率固有特性.给出了叶盘结构的扇区两自由度集中参数模型,计算并说明了其基本频率结构特性,根据叶盘结构模态振动物理背景,提出了一个定量表征模态振型局部化程度的指标-模态局部化因子,分别计算了不同随机刚度失谐叶盘结构固有频率和模态振型局部化的统计特性,讨论了失谐因素的影响规律等.研究表明,叶片和耦合刚度的失谐影响的频率区间有着明显的不同,并在其影响频段内模态局部化因子会出现"突变"的现象.

Based on the lumped-parametric model with two-degree-of-freedom per blade disk sector and its Monte Carlo simulation, the vibration characteristics of a typical bladed disk with different random mistuning of stiffness was researched, with particular regard to the subjects of the probability characteristics of natural frequencies and shapes. A lumped- parametric model was built and the natural mode properties of the model without mistuning were discussed. The definition of a modal localization factor was presented to assess quantitatively the behavior of shape localization for the mistuned bladed disk. Then the statistical characteristics of the natural frequencies and mode shapes were simulated and their main properties were explained. Results indicate that the influences of blade and coupling stiffness mistuning on modal characteristics are distinct in that they influence in different frequency ranges. And the localization factor in the frequency ranges affected by mistuning could change abruptly.