Fuzzy finite element model updating of bridges by considering the uncertainty of the measured modal parameters

Abstract

It is significant to consider the effect of uncertainty of the measured modal parameters on the updated finite element (FE) model, especially for updating the FE model of practical bridges, since the uncertainty of the measured modal parameters cannot be ignored owing to the application of output-only identification method and the existence of the measured noise. A reasonable method is to define the objective of the FE model updating as the statistical property of the measured modal parameters obtained by conducting couples of identical modal tests, however, it is usually impossible to implement repeated modal test due to the limit of practical situation and economic reason. In this study, a method based on fuzzy finite element (FFM) was proposed in order to consider the effect of the uncertainty of the measured modal parameters on the updated FE model by using the results of a single modal test. The updating parameters of bridges were deemed as fuzzy variables, and then the fuzz-ification of objective of the FE model updating was proposed to consider the uncertainty of the measured modal parameters. Finally, the effectiveness of the proposed method was verified by updating the FE model of a practical bridge with the measured modal parameters.