Dynamics of Multi-Stage Bladed Disks Systems

This paper presents a new and original method for dynamical analysis of multi-stage cyclic structures such as turbomachinery compressors or turbines. Each stage is modeled cyclically by its elementary sector and the inter-stage coupling is achieved through a cyclic recombination of the interface degrees of freedom. This method is quite simple to set-up; it allows to handle the finite element models of each stage’s sector directly and, as in classical cyclic symmetry analysis, to study the nodal diameter problems separately. The method is first validated on a simple case study which shows good agreements with a complete 360° reference calculation. An industrial example involving two HP compressor stages is then presented. Then the forced response application is presented in which synchronous of engine order type excitations are considered.