Abstract

The coupling vibration of a blade-disk-shaft unit is generally studied on the assumption that all the blades are identical. However, the mistuning feature always occurs due to manufacturing tolerances and other reasons in engineering practice. Therefore, a shaft-disk-blades coupling model with the random mistuning feature is derived based on our previous work. Then the statistical analysis on vibration characteristics of a blade-disk-shaft unit is performed. The uncertainty effects of blade parameters on coupling characteristics between the subcomponents are exhibited. The Monte Carlo simulation and statistical theory are used to capture the probability distributions of coupling characteristics. The natural frequency distributions of coupling modes are obtained under different mistuning levels and evaluated through confidence intervals. Then the mode shapes, obtained by eigenvector, are plotted to derive the evolution law of coupling mode type in a random mistuning system. At last, the localization factor is defined, then its statistical results are obtained to evaluate the mode localization magnitude under different mistuning levels.

摘要

叶片-盘-轴单元的耦合振动通常是在所有叶片相同的假设下进行研究的。然而，在工程实践中，由于制造公差等原因，经常会出现误调现象。因此，基于我们之前的工作，推导出具有随机失谐特征的轴-盘-叶片耦合模型。然后对叶片-盘-轴单元的振动特性进行统计分析。展示了叶片参数对子部件之间耦合特性的不确定性影响。蒙特卡罗模拟和统计理论用于捕获耦合特性的概率分布。获得不同失谐水平下耦合模式的固有频率分布，并通过置信区间进行评估。然后绘制由特征向量获得的模态振型，以推导随机失谐系统中耦合模态类型的演化规律。最后定义定位因子，并得到其统计结果，以评估不同失调水平下的模态定位幅度。