Using numerical experimentation as a tool for damage diagnosis

Vibration monitoring of civil engineering structures has gained a lot of interest over the past few years due to relative ease of instrumentation and the development of powerful system identification techniques. From long term measurements the altered dynamic characteristics of a damaged structure can be observed as a significant change in identified modal parameters. The paper proposes numerical experimentation as an alternative to the traditional gradient based model updating techniques for the quantification of damage in the structure. In this approach the differences between simulated and measured response are minimized with a Response Surface Model that is built from a large number of numerical experiments. The technique allows the analyst to describe damage patterns with specific parameters. Gradient evaluations for these parameters, as required by the sensitivity based model updating methods, are not always readily available from standard FE models. Furthermore no linearization of response quantities with respect to damage parameters is required and the interactions between different several damaged sections can be studied.