Control-based Finite-element Model Updating of Structures

Abstract

Finite-element model updating is the process of using measured data from a structure to update a numerical model representation of the structure. The measured data can represent either the static or dynamic properties of the structure. This document reviews and evaluates several methods of finite-element (FE) model updating, including direct, indirect, and control-based methods for the dynamic case. It is important to have a correct finite-element model obtained using model updating methods either to assess the current condition, or to modify the structure from its current state. In this study, three types of methods were evaluated; direct, indirect, and control based finite-element model updating methods. Each method was first used to update a simple example model for two separate cases. For the first case, the entire set of measured modal parameters were used; and for the second case, only a sub-set of the eigenvalues were used. These examples provide insights into the advantages and disadvantages of various methods. The model updating methods are also used to update a full-scale 42 degree of freedom model. Since it is not practical to measure all the degrees of freedom, the model was reduced using the SEREP model reduction method, down to 18 degrees of freedom. This was done to evaluate the effectiveness of the model updating methods on a real structure. Detailed methodologies and a comparison between the relative advantages and disadvantages between various model updating methods are highlighted in this thesis.