INCLUSION OF STATIC INDETERMINATION IN THE MATHEMATICAL-MODEL FOR NONLINEAR DYNAMIC ANALYSES OF MULTI-BEARING ROTOR SYSTEM

Static indetermination is a common problem in the dynamic analysis of most multi-bearing rotor systems. This paper presents a systematic treatment of this problem. It is taken into account at the stage when the general mathematical model is constructed for a complete multi-bearing rotor system. The practical significance of such a mathematical model is that it allows for the straightforward formulation of an approach for on-site identification of bearing alignment changes during system operation. Based upon this model, a computer system has been developed on a microcomputer for non-linear simulations of transient and steady state vibratory phenomena. Also, computer programs have been developed independently for modelling flexible complex rotors and journal bearings. A major feature of the non-linear computer system developed is that dynamic analysis of a multi-bearing rotor system can be carried out by changing the operating speed of the system, or by changing system configurations. Numerical examples are presented which demonstrate the successful application of the computer system to a four-bearing laboratory installation and a 200 MW turbogenerator unit. © 1993 Academic Press Limited.