On the Isolation of Modes in the Balancing of Flexible Shafts

Abstract

A method of balancing axially-symmetric flexible shafts has been given previously. The process of balancing requires the distortion to be magnified in successive modes so that each may be considered singly near its corresponding critical speed. It may be impossible to isolate a mode with sufficient purity when the shaft has a gross component defect (of bend or unbalance) in an adjacent mode or when critical speeds happen not to be widely spaced apart. Methods are suggested for overcoming the difficulty and the results of an experimental investigation of these proposals are included. The experiments were carried out both on a laboratory scale and on a large industrial rotor.