Abstract: A dynamic analysis technique which can be employed in a real centrifugal impeller with split blades is presented. It shows that multi-component partition can be made in repetitive sector region of the centrifugal impeller.The basic repetitive sector region of the centrifugal impeller is divided into three substructures; the guide blade, the split blade and the sectoral part of the disc. By using Benfield mode substitution transformation combined with group |transformation successfully, the Hermite generalized mass and stiffness matrices under the reduced coordinates are derived. From this, the natural frequencies of the bladed disc coupled system can be solved and the corresponding modal shapes are obtained through transformation.The comparison of the analysis results obtained by using the method presented in this paper and other methods, the experiment data of a testing modal verifies the reliability, practicability and considerable economic benefits of the method presented in this paper.

Key words: constraint substructure, loa3ed normal mode, reduced coordinates, substru-ctral simultaneous iteration.