826 Nonlinear Vibration Analysis of a Full-Circular Journal Bearing-Rotor System : Numerical Analysis using the Shooting Method and Analysis Based on the Polynomial Approximation under the Half Sommerfeld Boundary Condition

Abstract

This study investigates the nonlinear vibration of the flexible rotor supported by the journal bearing. The numerical simulation method, so called shooting method, is utilized to investigate both stable and unstable solution. Both the synchronous and asynchronous vibrations are analyzed. Because the shooting method is available only for the periodic vibration, the investigation of the asynchronous vibration can be performed only for the case without unbalance of the rotor system. To investigate the asynchronous vibration in the case with unbalance, an approximated force model of the journal bearing is developed. The validity of the proposed model is discussed by the numerical simulation and clarified.