Transverse Vibrations of a General Cracked-Rotor Bearing System

Abstract

In this study, the steady state response to the gravity and the unbalance force, and the major natural vibration of a general rotor bearing system with the open or open-close type crack, is analyzed along the iterative numerical calculation method (the transfer matrix method). The open-close type crack is idealized as a step function of the bending moment. The nonlinear equations are linearized by using the Fourier expansion technique, and its solutions are given approximately with the static deflection, the once/rev. vibration, and the twice/rev. vibration. The analyzed calculated method is confirmed by comparing the calculations with the experiments for a small test rotor. The rotor bearing system model in this method is as accurate as the usual numerical rotor dynamic analysis model, and also the required procedures for the calculation are almost the same.