Identification of bearing coefficients by incomplete mode shapes

Abstract

A new method to identify the moment and radial stiffness and damping coefficients of isotropic bearings in a spindle-bearing system with incomplete mode shapes is proposed. A complete relationship between the bearing reactions and the incomplete mode shapes is constructed in the form of a system of linear equations by using the transfer matrix method based on Timoshenko beam theory including the internal damping of beam material. In essence, the bearing coefficients are straightforwardly identified without any iteration from the system of linear equations. But, where inaccuracies of measured data produce unreasonable bearing coefficients, the linearisation method is used to solve a constrained minimisation problem to attain reasonable bearing coefficients. An experiment on a spindle-bearing test model reveals the usefulness of the proposed method.