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Towards an Automatic Modal Parameter Estimation Framework: Mode Clustering

Majid Khorsand Vakilzadeh (Institutionen för tillämpad mekanik, Dynamik ; Svenskt VindkraftsTekniskt Centrum (SWPTC)) ; Vahid Yaghoubi (Institutionen för tillämpad mekanik, Dynamik) ; Anders T Johansson (Institutionen för tillämpad mekanik, Dynamik) ; Thomas Abrahamsson (Institutionen för tillämpad mekanik, Dynamik)
Proceedings of the 33rd IMAC, A Conference and Exposition on Structural Dynamics, 2015; (Topics in Modal Analysis, Volume 10) (2191-5644). p. 243-259. (2015)
[Konferensbidrag, refereegranskat]

The estimation of modal parameters from a set of measured data is a highly judgmental task, with user expertise playing a significant role for distinguishing between physical and spurious modes. However, it can be very tedious especially in situations when the data is difficult to analyze. This study presents a new algorithm for mode clustering as a preliminary step in a multi-step algorithm for performing physical mode selection with little or no user interaction. The algorithm commences by identification of a high-order model from estimated frequency response functions to collect all the important characteristics of the structure in a so-called library of modes. This often results in the presence of spurious modes which can be detected on the basis of the hypothesis that spurious modes are estimated with a higher level of uncertainty comparing to physical modes. Therefore, we construct a series of data using a simple random sampling technique in order to obtain a set of linear systems using subspace identification. Then, their similar modes are grouped together using a new correlation criterion, which is called Modal Observability Correlation (MOC). An illustrative example shows the efficiency of the proposed clustering technique and also demonstrates its capability to dealing with inconsistent data.

Nyckelord: Clustering, FRF based N4SID, Inconsistent datam, Modal observability correlation, Modal parameters, QR- and singular value decomposition



Denna post skapades 2015-11-21. Senast ändrad 2017-06-28.
CPL Pubid: 226125

 

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Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Dynamik (1900-2017)
Svenskt VindkraftsTekniskt Centrum (SWPTC)

Ämnesområden

Teknisk mekanik

Chalmers infrastruktur