Component-mode-based reduced order modeling techniques for mistuned bladeddisks - Part I: Theoretical models

Component mode synthesis (CMS) techniques are widely used for dynamic analy ses of complex structures. Significant computational savings can be achieve d by using CMS, since a modal analysis is performed on each component struc ture (substruture). Mistuned bladed disks are a class of structures for whi ch CMS is well suited. In the context of blade mistuning, it is convenient to view the blades as individual components, while the entire disk may be t reated as a single component. Individual blade mistuning may then be incorp orated into the CMS model in a straightforward manner: In this paper, the C raig-Bampton (CB) method of CMS is formulated specifically for mistuned bla ded disks, using a cyclic disk description. Then a novel secondary mortal a nalysis reduction technique (SMART) is presented: a secondary modal analysi s is performed on a CB model, yielding significant further reduction in mod el size. In addition a straightforward non-CMS method is developed in which the blade mistuning is pi-ejected onto the tuned system modes. Though simi lar approaches have been reported previously, here it is generalized to a f orm that is more useful in practical applications. The theoretical models a re discussed and compared from both computational and practical perspective s. It is concluded that using SMART, based on a CB model, has tremendous po tential for highly efficient accurate modeling of the vibration of mistuned bladed disks.