Reduced-Order Modeling for Nonlinear Analysis of Cracked Mistuned Multistage Bladed-Disk Systems

with small blade-to-blade mistuning and a cracked blade is proposed. The modeling strategy is based on an efficient stagewise reduced-order modeling method based on cyclic symmetry analysis and component mode synthesis. Reduced-order modelsareconstructed forindividual stagesandassembledbyprojecting themotionof theinterface of the neighboring stages onto a set of harmonic shape functions. The analysis procedure allows the stages to have different numbers of blades and mismatched computational grids on the interfaces of the neighboring stages. Furthermore, the modeling framework is independent of the modeling method for each stage, which enables the use of various existing modeling methods of single stages. Moreover, nonlinearity can also be included in the multistage computations, as long as the nonlinearity can be modeled for a single stage. To demonstrate the capability of the modelingprocedure,thenonlineareffectofcrackopeningandclosingisconsidered,inconjunctionwiththeeffectsof small mistuning. The accuracy and efficiency of the proposed methods are discussed.