Reduced-Order Modeling for the Coupling Vibration Analysis of Bladed Rotors Supported by Journal Bearings

PurposeIn the dynamic analysis of bladed rotors, bladed disks and rotors tend to be dealt with independently, where the former ones usually neglect the flexibility of shaft and the latter ones often assume the blade and disk to be rigid. This paper integrates these two aspects and presents a model order reduction method for bladed rotors supported by journal bearings.MethodsThe coupling vibration characteristics of a bladed rotor-bearing system are addressed, where the mistuning in blades and disk is taken into account. The governing equations of motion of rotating bladed rotor-bearing systems are developed by employing 3D finite element (FE) model and the eight-coefficient model of bearing. The order of the model is significantly reduced before further analysis, and the mistuning in blades and disk are integrated into the reduced-order model (ROM).Results and ConclusionThe effectiveness of the proposed method is validated by comparing with the full-order model. Numerical results shown that the flexibility of shaft can lead to significant influences on the responses of mistuned bladed disk, in both one engine order (EO) and higher EOs of excitations. Besides, the bearing stiffness and disk mistuning have also non-negligible effects.