Application of joint time-frequency distribution for estimation of time-varying modal damping ratio

被引:0
|
作者
Bucher, H. [1 ]
Magluta, C. [1 ]
Mansur, W. J. [1 ]
机构
[1] Univ Fed Rio de Janeiro, Dept Civil Engn, COPPE, BR-21945970 Rio De Janeiro, Brazil
关键词
damping; modal damping; joint time-frequency distribution (JTFD); least squares complex exponential method (LSCE); SYSTEM-IDENTIFICATION; WAVELET TRANSFORMS; REPRESENTATIONS; SIGNALS; RIDGES; MODES; WIND;
D O I
暂无
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
The logarithmic decrement method has been long used to estimate damping ratios in systems with only one modal component such as linear single degree of freedom (SDOF) mechanical systems. This paper presents an application of a methodology that uses joint time-frequency distribution (JTFD) as input, instead of the raw signal, to systems with several vibration modes. A most important feature of the present approach is that it can be applied to a system with time-varying damping ratio. Initially the precision and robustness of the method is determined using a synthetic model with multiple harmonic components, one of them displaying a time-varying damping ratio, subsequently the results obtained from experiments with a reduced model are presented. A comparison is made between the results obtained with this methodology and those using the classical technique of Least Squares Complex Exponential Method (L,SCE) in order to highlight the advantages of the former, such as, good precision, robustness and excellent performance in extreme cases, e.g., when very low frequency components and time varying damping ratio are present.
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页码:131 / 147
页数:17
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