模型缩减法在转子动力学中的应用比较

Comparison study of application of model reduction in rotor dynamics

随着大规模模型的不断增加,模型缩减在动力学分析中显得越来越重要,模型缩减在保证精度的基础上可以减少存储空间和提高计算效率。常见的模型缩减法主要有静态缩减法(Guyan)、动态缩减法(Dynamic reduction)、改进的缩减系统法(IRS)、系统等价扩展缩减法(System equivalent expansion reduction process)以及部件模态综合法(CMS)。从理论上介绍了几种模型缩减法的不同,而且通过这几种方法对有限元法建立的简单单转子系统进行临界转速的分析,比较分析它们在准确度以及计算效率的差别。结论:1)在计算效率和准确性上,IRS法和CMS法表现较好;2)静态缩减法只在零频时结果精确,可靠性较差;动态缩减法在特定频率下结果较精确;SEREP法计算结果比静态缩减法和动态缩减法要精确,但是精度和计算效率低于CMS法和IRS法;3)CMS法在预测高频运动时结果更准确。

As more and more large models are adopted in practice, model reduction becomes an important issue in rotor dy-namics. Based on accurate prediction, model reduction can reduce storage and simulation time. The typical methods areGuyan reduction, dynamic reduction, improved reduce system （ IRS）, system equivalent expansion reduction process andcomponent mode synthesis method. A shaft - line model of a single rotor system is established with the finite element meth-od. By analyzing the dual - rotor system of its analogous dynamic characteristics, the accuracy and computation efficiency ofdifferent methods are compared. The results are as the following： 1 ） Compared with different reduction methods, IRS andCMS deliver the best eigenfrequency results. 2 ） Guyan reduction is only exact at zero frequency, dynamic reduction can beexact at the chosen frequency, SEREP method is better than Guyan reduction and dynamic reduction in accuracy, but whenpredicting high frequency motion it is less accurate and less efficient than CMS and IRS method. 3 ） CMS method has betteraccuracy in predicting high frequency motion.