The journal bearings are used to support high-speed rotors in turbo machinery which often operate above the rotor first bending critical speed. This bearing provide both lateral support and dynamic coefficients: Stiffness, damping, and mass terms, related to machine vibrations. The various methods of identifying journal bearing dynamic characteristics, from measured data, obtained from different measurement systems, are reviewed. The various approaches to the bearing identification problem are discussed. The various data processing methods in the time and frequency domains are presented. Also, vibration and condition monitoring techniques are presented. In this review, the relative strengths and weaknesses of bearing are presented and developments and trends in improving bearing measurements are documented. Future trends of journal bearing are discussed.
