Abstract
It is well known that the mode shapes are not mass normalized in the operational modal analysis process. In the last years several equations have been proposed to scale de mode shapes using the mass change method, which consists of modifying the dynamic behavior of the structure attaching some masses at positions where the mode shapes are known. The modal masses are then estimated using the modal parameters of both the unperturbed and the perturbed systems together with the mass change matrix corresponding to the applied perturbations.
In this paper it is proposed a new technique to scale the mode shapes in operational modal analysis which consists of combining the mass matrix of a finite element model and the experimental mode shapes identified by operational modal analysis. It is proven that, if a reasonable correlation exists between the experimental and the numerical systems, the results provided by this method are of the same order of accuracy as the results of the mass change method.
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Acknowledgments
The economic support given by the Spanish Ministry of Science and Innovation through the project BIA 2011-28380- C02-01 is gratefully appreciated.
The research reported in this paper was carried out during a stay at the Department of Engineering of the Aarhus University, Denmark, the support provided during this stay is gratefully acknowledged.
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Aenlle, M.L., Brincker, R. (2014). Modal Scaling in OMA Using the Mass matrix of a Finite Element Model. In: Catbas, F. (eds) Dynamics of Civil Structures, Volume 4. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-319-04546-7_30
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DOI: https://doi.org/10.1007/978-3-319-04546-7_30
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