Mj. Ratcliffe et Naj. Lieven, An investigation into the effects of frequency response function estimators on model updating, MECH SYST S, 13(2), 1999, pp. 315-334
Model updating is a very active research field, in which significant effort
has been invested in recent years. Model updating methodologies are invari
ably successful when used on noise-free simulated data, but tend to be unpr
edictable when presented with real experimental data that are-unavoidably-c
orrupted with uncorrelated noise content. In the development and validation
of model-updating strategies, a random zero-mean Gaussian variable is adde
d to simulated test data to tax the updating routines more fully. This pape
r proposes a more sophisticated model for experimental measurement noise, a
nd this is used in conjunction with several different frequency response fu
nction estimators, from the classical H-1 and H-2 to more refined estimator
s that purport to be unbiased. Finite-element model case studies, in conjun
ction with a genuine experimental test, suggest that the proposed noise mod
el is a more realistic representation of experimental noise phenomena. The
choice of estimator is shown to have a significant influence on the viabili
ty of the FRF sensitivity method. These test cases find that the use of the
H-2 estimator for model updating purposes is contraindicated, and that the
re is no advantage to be gained by using the sophisticated estimators over
the classical H-1 estimator. (C) 1999 Academic Press.