Due to its potential impact, the mode localization has been studied via different approaches, such as component-mode synthesis [5,6], the Rayleigh–Ritz method [7,8], the Taylor series [9], and the finite-element methods [10]. In many of these studies, a simplified bladed-disk model is used as a benchmark to facilitate prediction of the model localization. The benchmark model often has a single disk with multiple blades simulating a single-stage rotor. In addition, the inner rim of the bladed-disk is fixed to simplify the analysis. Although the simplified model has successfully demonstrated the phenomenon of mode localization, the model does not account for the effects of other machine components, such as the shaft supporting the bladed disk, bearings, and housing. Therefore, how these machine components would affect mode localization remains unknown. Moreover, if these components did affect mode localization, what would be the underlying mechanisms and physics? If the mode localization was affected, what would be its implication to the performance of the entire rotor assembly?