Finite element model updating for structural applications

Maria Girardi, Cristina Padovani, Daniele Pellegrini, Margherita Porcelli, Leonardo Robol

Published 2018-01-27Version 1

A novel method to perform model updating on finite element models is presented. The approach is particularly tailored to modal analysis of buildings, where the lowest frequencies, obtained by using sensors and system identification approaches, need to be matched to the numerical ones predicted by the model. This is done by optimizing some unknown parameters (such as mass density and Young's modulus) of the materials and/or boundary conditions, which are often only approximately known. In particular, this is the case when considering historical buildings. The straightforward application of a general-purpose optimizer can be unpractical given the large size of the model involved; we show that, by slightly modifying the projection scheme used to compute the eigenvalues at the lowest end of the spectrum one can obtain local parametric reduced order models that, embedded in a trust-region scheme, are the basis of a reliable and efficient specialized algorithm. We describe an optimization strategy based on this construction, and we provide numerical experiments that confirm its effectiveness and accuracy.