Vibration Modes of Packeted Bladed Disks

Abstract

This paper presents the results of investigating the vibrational behavior of turbine blades when grouped into packets. Two methods of analysis based on substructuring via receptance coupling have been developed and used with success to predict the natural frequencies of a 30-bladed disk with various packeting arrangements. A series of experiments have been conducted on a special testpiece to confirm these predictions. It is found that, unlike its continuously shrouded counterpart, the packeted bladed disk has modes which are always complex in shape, containing several nodal diameter components, a feature which can be predicted from the modal interference diagrams introduced in this work.