Vibration mechanism of a mistuned bladed-disk

For coupling vibration of the mistuned bladed-disk in aeroengine, the vibration differential equation of the system is established using component-mode synthesis methods. Experimental mode analysis and mode correction are used to calculate some low-order modes of tuned blade and the disk with cone-flange. The models of actual mistuned bladed-disk is constructed by exerting some small perturbation on the mode stiffness of blades. The forced vibration experimentation of an actual mistuned bladed-disk in non-rotating status is carried out to verify the vibration model and calculation formulae. The results show that excessive vibration response of a single blade is caused by blade mistuning, and the random mistuning distribution of a small frequency difference is more profitable than other arrangements for depressing the maximal vibration level of the hapless blade. In this study, the better natural frequency difference amplitude of blades and the right working frequency range of aeroengine are also suggested according to the result analysis of several numerical calculations. (c) 2008 Elsevier Ltd. All rights reserved.