Issue 29

E. Grande et alii, Frattura ed Integrità Strutturale, 29 (2014) 325-333; DOI: 10.3221/IGF-ESIS.29.28 325 Focussed on: Computational Mechanics and Mechanics of Materials in Italy A data fusion based approach for damage detection in linear systems Ernesto Grande, Maura Imbimbo University of Cassino and Southern Lazio, Depart. of Civil and Mechanical Engineering e.grande@unicas.it , mimbimbo@unicas.it A BSTRACT . The aim of the present paper is to propose innovative approaches able to improve the capability of classical damage indicators in detecting the damage position in linear systems. In particular, starting from classical indicators based on the change of the flexibility matrix and on the change of the modal strain energy, the proposed approaches consider two data fusion procedures both based on the Dempster-Shafer theory. Numerical applications are reported in the paper in order to assess the reliability of the proposed approaches considering different damage scenarios, different sets of modes of vibration and the presence of errors affecting the accounted modes of vibrations. K EYWORDS . Damage Identification; Modal Strain Energy; Flexibility Matrix; Data-Fusion I NTRODUCTION umerous studies concerning the development of damage indicators mainly based on the modal parameters of systems derived from identification processes, in some cases combined with finite-element model update algorithms, are available in the current literature [1-3]. Some of these indicators, coupled with innovative algorithms, provide information on the position and the severity of damage [4-6]. Among these, the relative damage indicator (rdi) and the modal strain energy change ratio (MSECR j ) indicators, respectively based on the change of the flexibility matrix and the modal strain energy of systems before and after the damage, are widely used for damage detection in linear systems [7, 8]. They are defined as:   d e e e diag F F rdi diag F   (1)   1 1 max n ij j i ij j MSECR MSECR N MSECR    (2) where F e and F e d is the elemental flexibility matrix of the system before and after damage respectively, MSECR ij is the modal strain energy change ratio corresponding to the ith mode of vibration and to the jth element of the system and N is the number of elements composing the system. N