Abstract

The results of a complete study of mistuning identification on an industrial blisk are presented. The identification method used here is based on a model-updating technique of a reduced-order model where measured modal data are taken as input. This reduced-order model is build using component mode synthesis and mistuning is introduced as perturbations of the cantilevered-blade modes. The measured modal data are extracted from global measurements of the blisk’s forced response. As we use a one point excitation, this measurement procedure allows the acquisition of the all modes of a given family with a quite simple experimental setup. A selection of the best identified modal data is finally performed. During the mistuning identification procedure, these measured data are regularized using an eigenvector assignment technique which reduces the influence of eventual measurement errors. An inverse problem is defined based on the perturbed (mistuned) modal equation, with measured modes as input and mistuning parameters as unknown. Then, the reduced-order model is updated with the identified mistuning, we first perform a correlation on modal responses (using eigenfrequency deviation criteria and MACs). Finally, correlation results on forced responses are presented and discussed.

Highlights

  • Mistuning of turbomachinery bladed disks refers to small variations of structural or geometrical properties between each sector

  • A classical component-mode synthesis method adapted to cyclic structures will be used in order to build a representative model of mistuned bladed disk

  • Feiner and Griffin [13, 14] have proposed a method of identification for a whole sector of a bladed disk based on a reduced-order modelling method called fundamental mistuning model, they proposed a completely experimental strategy

Read more

Summary

INTRODUCTION

Mistuning of turbomachinery bladed disks refers to small variations of structural or geometrical properties between each sector. A classical component-mode synthesis method adapted to cyclic structures will be used in order to build a representative model of mistuned bladed disk Another issue concerning the study of mistuned bladed disks is the ability to predict the resonant response to random mistuning distribution. Feiner and Griffin [13, 14] have proposed a method of identification for a whole sector of a bladed disk based on a reduced-order modelling method called fundamental mistuning model, they proposed a completely experimental strategy Another method, proposed by Pichot et al [15] and used is this study, is based on a component mode synthesis and uses an original technique of eigenvalue assignment [16, 17] combined with a regularization technique which minimizes the effect of measurement errors. The complete experimental investigations, adapted to industrial blisks in regard to its simplicity procedure, are presented followed by the identification and model updating procedures; the correlation results on modal and forced responses are presented

Cyclic symmetry reduction
Component-mode synthesis
Mistuning representation
MISTUNING IDENTIFICATION TECHNIQUE
Inverse problem definition
Expansion-reduction steps for measured data
Eigenvalue assignment and regularization techniques
Identification of mistuning parameters
Measurements
Measurement procedure
Modal identification
Identification results and correlation of modal responses
Correlation of forced responses
CONCLUSIONS
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call