Vibratory diagnosis by finite element model updating and operational modal analysis

• Published in: Mechanics & industry : an international journal on mechanical sciences and engineering applications Vol. 14; no. 2; pp. 145 - 149
• Main Authors: Gautier, G., Serra, R., Mencik, J.-M.
• Format: Journal Article
• Language: English
• Published: Villeurbanne EDP Sciences 01.01.2013
• Subjects: finite elements model updating; operational modal analysis; rotating machine; Subspace fitting; vibratory diagnosis
• ISSN: 2257-7777; 2257-7750; 2257-7750
• DOI: 10.1051/meca/2013055

In this paper, a subspace fitting method is proposed to update, in the time domain, the finite element model of a rotating machine. The procedure is achieved by minimizing an error norm, leading to the comparison between experimental and theoretical observability matrices. Experimental observability matrix is obtained through a MOESP subspace identification algorithm, by projecting the output signal onto some appropriate subspaces, resulting in a cancellation of input excitations and noises. The theoretical observability matrix is obtained from modal parameters of a finite element model of the structure. The minimization procedure is carried out through a Gauss-Newton algorithm. The method is applied to determine the foundation stiffness of an experimental rotating machine subject to a random noise.