Reduced-Order Modeling of Bladed Disks Considering Small Mistuning of the Disk Sectors

A model order reduction method based on the Component Mode Synthesis for mistunend bladed disks is introduced, with one component for the disk and one component for each blade. The interface between the components at the blade roots is reduced using the wave-based substructuring method, which employs tuned system modes. These system modes are calculated first, and used subsequently during the reduction of the individual components, which eliminates the need to build a partially reduced intermediate model with dense matrices. For the disk, a cyclic Craig-Bampton reduction is applied. The deviations of the stiffness and mass matrices of individual disk sectors are then projected into the cyclic basis of interior and interface modes of the disk substructure. Thereby it is possible to model small disk mistuning in addition to large mistuning of the blades.