EXPERIMENTAL IDENTIFICATION OF EXCITATION AND SUPPORT PARAMETERS OF A FLEXIBLE ROTOR-BEARINGS-FOUNDATION SYSTEM FROM A SINGLE RUN-DOWN

Field balancing of rotors with unknown foundation dynamics is more often than not a painstaking, time-consuming and expensive process. A recent method to identify both the excitation and flexible support parameters of a rotor-bearings-foundation system has been verified experimentally in this paper. In addition to mass unbalance, the excitation due to a bent rotor has been included in the method, which has great potential in the field, since it allows balancing to be performed using data obtained from just a single run-up or run-down. Using this single-shot balancing technique, vibration levels of an experimental rotor rig were successfully reduced to less than one-tenth of their original levels. The geometry of a bent rotor has also been accurately identified and it was shown that including bend identification in those cases where only unbalance forcing was present in no way detracted from the accuracy of the estimated unbalance or foundation parameters. The identification of the flexible foundation parameters was generally successful, with measured and estimated parameters matching very closely in most cases. The identification method was tested for a wide range of conditions, and proved suitably robust to changes in system configuration, noisy data and modelling error.