کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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559652 | 875094 | 2011 | 14 صفحه PDF | دانلود رایگان |
In the past decade damping-identification methods based on the continuous wavelet transform (CWT) have been shown to be some of the best methods for analyzing the damping of multi-degree-of-freedom systems. The CWT methods have proven themselves to be resistant to noise and able to identify damping at closely spaced natural frequencies. However, with the CWT-based techniques, the CWT needs to be obtained on a two-dimensional, time–frequency grid, and they are, therefore, computationally demanding. Furthermore, the CWT is susceptible to the edge effect, which causes a non-valid identification at the start and the end of the time-series.This study introduces a new method, called the Morlet-wave method, where a finite integral similar to the CWT is used for the identification of the viscous damping. Instead of obtaining the CWT on a two-dimensional grid, the finite integral needs to be calculated at one time–frequency point, only. Then using two different integration parameters, the damping ratio can be identified. A complete mathematical background of the new, Morlet-wave, damping-identification method is given and this results in a root-finding or a closed-form solution.The presented numerical experiments show that the new method has a similar performance to the CWT-based damping-identification methods, while the method is numerically, significantly less demanding, completely avoids the edge effect, and the procedure is straightforward to use.
Journal: Mechanical Systems and Signal Processing - Volume 25, Issue 5, July 2011, Pages 1632–1645