A fundamental question that arises in finite element model updating and error localization problems is which requirements that have to be fulfilled by the physical parameters to be used in the procedures.
One requirement is that the test data are informative with respect to the chosen parameters. That implies that a change of a certain parameter should give a detectable change in the model’s dynamic behaviour. Another requirement is that the chosen parameters should be identifiable. The dynamic properties of a structure, as recorded by a measurement system, may under certain conditions change similarly by changing one parameter or a set of other parameters. Should that be the case, there is no identifiability.
This article shows that parameters of which test data have low informativeness and parame- ters that are lacking identifiability, are of no use for error localization or model updating and should therefore not be used for these purposes. Thus, before a meaningful error localization may take place either complementary test data have to be added or a re-parameterization of the model has to be made.
Before an error localization is to be carried out a preparatory error localization, using only data from an FE-analysis, is justified. The purpose of such preparatory work is both to decide which parameters to use to quantify model errors and to design the tests for the error localiza- tion in order to meet the parameter requirements.
Kassel, Germany, 2001.
International Conference on Structural System Identification, Kassel, Germany