Reduced-Order Modeling Approach for Blisks with Large Mass, Stiffness, and Geometric Mistuning

Abstract

Deviations to the cyclic symmetry of turbomachinery blisks are common due to manufacturing, general wear, or foreign object damage. These deviations, called mistuning, can lead to dramatically increased forced responses of a few of the blades. The high computational cost associated with predictions for mistuned blisks has led to the development of various reduced-order modeling techniques. This paper introduces a new reduced-order modeling approach for both large and small mistuning. This approach makes use of a pristine-rogue-interface modal expansion (PRIME). The PRIME basis is a new basis composed of modes computed only from cyclic symmetry analyses.Bystrategicallyprojectinga finiteelementmodelfromthephysicalspaceontothenewbasis,itispossibleto accurately and efficiently model large mistuning. In addition, the new method can account for both large and small mistuning simultaneously, using an extension of the component mode mistuning approach. The methodology requires only sector-level calculations and therefore can be applied to highly refined, realistic models of industrial size.