Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
OPERATIONAL MODAL ANALYSIS APPLIED TO A NUMERICAL ROTOR MODEL
Submission Author:
Gustavo Storti , SP
Co-Authors:
Gustavo Storti, Tiago Machado, Katia Lucchesi Cavalca Dedini, Leonardo Ishimoto
Presenter: Gustavo Storti
doi://10.26678/ABCM.COBEM2019.COB2019-0412
Abstract
Operational Modal Analysis (OMA), used initially at civil structures, has also increasingly gained importance in the mechanical field. The purpose of this paper is to investigate the use of OMA algorithms in a numerical model of a rotating machine with hydrodynamic bearings. The rotor is modelled using finite element method and the bearings are approximated by a linearized approach, extracting the dynamic coefficients from the model. Then, the rotor is excited with a white gaussian noise and its time response is used as input for the OMA technique, estimating the modal parameters from a time domain method, Stochastic Subspace Identification, and a frequency domain method, Enhanced Frequency Domain Decomposition, using software ARTeMIS®. The model data allowed to study the influence in the modal factors of different parameters of the simulations. Frequency domain methods showed a straightforward peak picking technique of resonance regions at the singular value decomposition of the power spectral densities of the signal, but the parameters obtained from time domain methods presented higher accuracy for closed spaced modes and better estimation for damping ratios and natural frequencies.
Keywords
Operational Modal Analysis, rotating machines, Numerical Modeling
