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 th an 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 a llows balancing to be performed using data obtained from just a single run- up or run-down. Using this single-shot balancing technique, vibration level s of an experimental rotor rig were successfully reduced to less than one-t enth of their original levels. The geometry of a bent rotor has also been a ccurately identified and it was shown that including bend identification in those cases where only unbalance forcing was present in no way detracted f rom the accuracy of the estimated unbalance or foundation parameters. The i dentification of the flexible foundation parameters was generally successfu l, with measured and estimated parameters matching very closely in most cas es. The identification method was tested for a wide range of conditions, an d proved suitably robust to changes in system configuration, noisy data and modelling error. (C) 2000 Academic Press.