A MODIFIED INFLUENCE COEFFICIENT METHOD FOR BALANCING UNSYMMETRICAL ROTOR-BEARING SYSTEMS

摘要

A formulation of influence coefficient matrices is derived from the equations of motion for unsymmetrical rotors by using a complex co-ordinate representation and the finite element method. Due to the unequal properties in the two principal directions, the present formulation results in two sets of modified influence coefficients. The formulation indicates that two trial masses placed in different directions are required in the two trial operations for each balancing plane. Also, from the analysis, the modified influence coefficients are found to be correlated to forward precession and imbalanced forces when the asymmetry of the bearings is considered. Therefore one requires forward precessions instead of measured displacements to calculate the influence coefficients and imbalance distribution. Several examples are presented to verify the validity of the present work. (C) 1996 Academic Press Limited [References: 16]