YANG Chen, DAI Hong-hui (Earthquake Engineering Research Center, IWHR, Beijing 100048, China)

Abstract: In the frequency domain, the modal parameters identification results are greatly affected by the accuracy of frequency response function. Since high resolution and smoothness cannot be satisfied at the same time in the traditional frequency response function estimation algorithm, this paper presents a successive zoom FFT spectrum analysis algorithm to increase the resolution of frequency response function (FRF) in heavy coupled and half-power bandwidth band. Then such frequency response function is used with the frequency domain Levy algorithm to get modal parameters. Numerical result shows that the high accuracy and resolution of frequency response function improve the accuracy of modal parameters result and resistance to noise. In a large ship lift shaking table model test, the application of the proposed methods obtains satisfactory results.

Key words: successive zoom FFT spectrum analysis, frequency response function, Levy, modal parameters analysis

Published in: Journal of China Institute of Water Resources and Hydropower Research (Vol. 10 No. 4, 2012)