Fast eigensystem realization algorithm based structural modal parameters identification for ambient tests

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Journal of Vibration and Shock ›› 2018, Vol. 37 ›› Issue (6) : 55-60.

PU Qianhui1，HONG Yu1，WANG Gaoxin2，LI Xiaobin1

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Abstract

The proposed fast eigensystem realization algorithm (FERA) is an improvement of the ERA, which can improve the calculation efficiency and cut down the data storage. To avoid the singular value decomposition of Hankel matrix, the eigenvalue decomposition of a newly built symmetric matrix was adopted in the method. Asimulated fourstory frame structure was utilized for validating the accuracy and efficiency of the FERA method. The scaled El Centro earthquake was applied to the structure as an unknown excitation. Both FERA and ERA methods were used for extracting the modal parameters from the simulated displacements, velocities and accelerations, respectively. After comparing the modal analysis results with the analytical values, the conclusions show that the FERA can accurately identify modal parameters from any type of dynamic responses, and the computational speed can increase rapidly. In addition, the FERA was used for extracting modal parameters of an inservice pedestrian bridge through ambient test, and the results show that the proposed method can also work for the actual structure.

Key words

FERA / ambient excitation / dynamic response;modal parameter identification

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PU Qianhui1，HONG Yu1，WANG Gaoxin2，LI Xiaobin1. Fast eigensystem realization algorithm based structural modal parameters identification for ambient tests[J]. Journal of Vibration and Shock, 2018, 37(6): 55-60

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