Estimating Turbogenerator Foundation Parameters - Model Selection and Regularisation

MG Smart (National Power, UK), MI Friswell & AW Lees (University of Wales Swansea)

Proceedings of the Royal Society of London, Series A: Mathematical, Physical and Engineering Sciences, Vol. 456, No. 1999, July 2000, 1583-1607


Estimating a model of the foundation of large machines, such as turbogenerators, is vital for tasks such as fault diagnosis and modal balancing. Unfortunately it is rarely possible to perform a modal test on the foundations without the rotor present. This paper considers a method to estimate a foundation model using response data from a run-down, using the inherent unbalance of the rotor to excite the foundations. The method requires an accurate model of the rotor and an approximate model of the bearings. Of critical importance is the quality of the model, which may be defined as the ability of the model to predict the response to unbalance excitations that are different from that present for the identification. It is shown in this paper that correct model selection and regularisation are vital to produce a foundation model that meets this predictability criterion. The method is validated using simulated data and also experimental data from a test rig with a 4 m long rotor with four fluid film bearings.

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Link to paper using doi:10.1098/rspa.2000.0577

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