A TRANSFER-MATRIX APPROACH TO FREE-VIBRATION LOCALIZATION IN MISTUNEDBLADE ASSEMBLIES

A study of mode localization in mistuned bladed disks is performed usi ng transfer matrices. The transfer matrix approach yields the free res ponse of a general, mono-coupled, perfectly cyclic assembly in closed form. A mistuned structure is represented by random transfer matrices, and the expansion of these matrices in terms of the small mistuning p arameter leads to the definition of a measure of sensitivity to mistun ing. An approximation of the localization factor, the spatially averag ed rate of exponential attenuation per blade-disk sector, is obtained through perturbation techniques in the limits of high and low sensitiv ity. The methodology is applied to a common model of a bladed disk and the results verified by Monte Carlo simulations. The easily calculate d sensitivity measure may prove to be a valuable design tool due to it s system-independent quantification of mistuning effects such as mode localization. (C) 1996 Academic Press Limited