Modeling of Uncertainties in Bladed Disks Using a Nonparametric Approach

In the field of turbomachinery, the assumption of cyclic symmetry of the different rotor stages is usually made to reduce the required computational resources. However, in reality small random blade-to-blade variations, known as mistuning, appear due to manufacturing tolerances, wear during use, etc. and disturb the dynamic behavior of bladed disks. This work proposes a new combination of two modeling techniques, incorporating the advantages of both methods to model more precisely the mistuned response of bladed disks with reduced computational time. In particular, we combine the reduced-order modeling technique based on cyclic symmetry with the nonparametric approach for modeling uncertainties in order to introduce them directly in the modal space of the blades of the structure and thus reduce the size of the model. We perform a numerical comparison between the frequency response function of a bladed structure. The proposed method allows to retrieve the results of the nonparametric approach while reducing the size of the structural matrices.