An approach to operational modal analysis using the expectation maximization algorithm

Cara Cañas, Francisco Javier and Carpio Huertas, Jaime and Juan Ruiz, Jesús and Alarcón Álvarez, Enrique (2012). An approach to operational modal analysis using the expectation maximization algorithm. "Mechanical Systems and Signal Processing", v. 31 ; pp. 109-129. ISSN 0888-3270. https://doi.org/10.1016/j.ymssp.2012.04.004.

Description

Title: An approach to operational modal analysis using the expectation maximization algorithm
Author/s:
  • Cara Cañas, Francisco Javier
  • Carpio Huertas, Jaime
  • Juan Ruiz, Jesús
  • Alarcón Álvarez, Enrique
Item Type: Article
Título de Revista/Publicación: Mechanical Systems and Signal Processing
Date: August 2012
ISSN: 0888-3270
Volume: 31
Subjects:
Freetext Keywords: Structural dynamics; Operational modal analysis; System identification; Stochastic subspace identification method; Maximum likelihood estimation; Expectation Maximization algorithm
Faculty: E.T.S.I. Industriales (UPM)
Department: Ingeniería de Organización, Administración de Empresas y Estadística
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

This paper presents the Expectation Maximization algorithm (EM) applied to operational modal analysis of structures. The EM algorithm is a general-purpose method for maximum likelihood estimation (MLE) that in this work is used to estimate state space models. As it is well known, the MLE enjoys some optimal properties from a statistical point of view, which make it very attractive in practice. However, the EM algorithm has two main drawbacks: its slow convergence and the dependence of the solution on the initial values used. This paper proposes two different strategies to choose initial values for the EM algorithm when used for operational modal analysis: to begin with the parameters estimated by Stochastic Subspace Identification method (SSI) and to start using random points. The effectiveness of the proposed identification method has been evaluated through numerical simulation and measured vibration data in the context of a benchmark problem. Modal parameters (natural frequencies, damping ratios and mode shapes) of the benchmark structure have been estimated using SSI and the EM algorithm. On the whole, the results show that the application of the EM algorithm starting from the solution given by SSI is very useful to identify the vibration modes of a structure, discarding the spurious modes that appear in high order models and discovering other hidden modes. Similar results are obtained using random starting values, although this strategy allows us to analyze the solution of several starting points what overcome the dependence on the initial values used.

More information

Item ID: 15309
DC Identifier: http://oa.upm.es/15309/
OAI Identifier: oai:oa.upm.es:15309
DOI: 10.1016/j.ymssp.2012.04.004
Official URL: http://www.sciencedirect.com/science/article/pii/S0888327012001306
Deposited by: Biblioteca ETSI Industriales
Deposited on: 14 May 2013 10:14
Last Modified: 21 Apr 2016 15:22
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