Mistuning Identification of Blisks at Higher Frequencies

Abstract

There is a large body of research on reduced-order modeling of bladed disks and integrally bladed disks (blisks) for predicting the mistuned vibration response. However, most work to date has focused on the lower frequency families of blade-dominated modes. Relatively few studies have considered the response in higher frequency regions that feature more complex blade motions and more closely spaced families of modes. Moreover, some reduced-order modeling techniques for mistuned blisks make use of simplifications inherent in lower frequency ranges and neglect complexities of higher frequency ranges. In this study, key challenges of higher frequency regimes are considered. Procedures are presented and evaluated for reduced-order modeling and mistuning identification of blisks at frequency ranges beyond the first few families of blade-dominated modes. It is shown that mistuning patterns can be identified for higher mode families, and the mistuning pattern for each family is generally unique when the physical mistuning is not uniform throughout each blade. Finally, a procedure to choose appropriate measurement points for modeling and mistuning identification is proposed.