An Experimental Investigation of Vibration Localization in Bladed Disks: Part I — Free Response

The results of an experimental investigation of the effects of random blade mistuning on the free dynamic response of bladed disks are reported. Two experimental specimens are considered: a nominally periodic twelve-bladed disk with equal blade lengths, and the corresponding mistuned bladed disk, which features slightly different, random blade lengths. In the experiment, both the spatially extended modes of the tuned system and the localized modes of the mistuned system are identified. Particular emphasis is placed on the transition to localized mode shapes as the modal density in various frequency regions increases. Excellent qualitative and quantitative agreement is obtained between experimental measurements and results obtained by finite element analysis. Experimental results are additionally used to validate a component mode-based, reduced-order modeling technique for bladed disks. This work reports the first systematic experiment carried out to demonstrate the occurrence of vibration localization in bladed disks.Copyright © 1997 by ASME