THEORY AND EXPERIMENT ON A METHOD FOR ON-SITE IDENTIFICATION OF CONFIGURATIONS OF MULTI-BEARING ROTOR SYSTEMS

A general approach has been developed for on-site identification of the actual configuration (alignment) of multi-bearing rotor systems (e.g., a turbogenerator unit). The identification procedure is based on the monitored trajectories of the relative motion of the journals with respect to the bearings and a non-linear mathematical model of the system considered. The mathematical model includes the dynamic properties of rotors, their foundations and supporting structures as well as the non-linear properties of the oil bearings. Time integration of the non-linear equations of motion along the measured trajectories yields the desired configuration parameters (relative transverse positions of the bearing centres). The derived procedure of identification was verified by means of a computer simulation as well as an experimental investigation on a four-bearing rotor test installation. The results may be used for the diagnosis of vibration problems in rotating machinery as well as the optimization of their vibration response. © 1993 Academic Press Limited.