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Structural concentration modal parameter recognition method based on Moret wavelet transformation

A technology of modal parameter identification and wavelet transform, which is applied in character and pattern recognition, instruments, computer components, etc., can solve problems such as identification of structural modal parameters that have not yet been formed

Inactive Publication Date: 2011-10-19
SOUTHEAST UNIV
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Problems solved by technology

The choice between the two is often subjective
[0007] (3) Using Moret wavelet transform to identify structural modal parameters, a set of standardized procedures for identifying structural modal parameters using Moret wavelet transform has not yet been formed

Method used

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  • Structural concentration modal parameter recognition method based on Moret wavelet transformation
  • Structural concentration modal parameter recognition method based on Moret wavelet transformation
  • Structural concentration modal parameter recognition method based on Moret wavelet transformation

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Embodiment Construction

[0043] (1) Define the judgment index of dense mode of civil engineering structure.

[0044] Through the wavelet cumulative energy spectrum, the vibration natural frequency of the structure can be known a priori (ie ω r known a priori). If ω r >1.12, the adjacent mode is a sparse mode; otherwise, it is a dense mode. If the mode is a dense mode, it is judged whether the dense mode can be decoupled through the sudden change (sign change) of the slope of the wavelet transform index amplitude curve near the initial value, that is, whether there is strong interference. Specific steps are as follows:

[0045] For a multi-degree-of-freedom system, the wavelet index of its free decay response is:

[0046] W g x ( a , b ) ≈ 2 πa 2 Σ i = 1 ...

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Abstract

The invention relates to a structural concentration modal parameter recognition method based on Moret wavelet transformation. A wavelet amplitude curve and a wavelet phase curve are analyzed by using an improved modal parameter recognition method on the basis of the Moret wavelet transformation theory so that various orders of modal frequency and modal damping of a structure are calculated. According to the invention, criterions of civil engineering structure concentration modals are quantitatively defined, a method for determining structural frequency according to wavelet accumulating energy spectrum is provided, a wavelet center frequency optimizing algorithm is established, and the process of carrying out the damping ratio recognition on applied wavelet transformation is improved. On the basis, the invention provides a full set of flow of the structural concentration modal parameter recognition method based on the Moret wavelet transformation. The method has the advantages of improving the precision of wavelet transformation recognition structural modal parameters, effectively avoiding the influence caused by end effects, and overcoming the subjectivity, the experience and theblindness of selecting a wavelet transformation centre frequency and a wavelet amplitude fitting region, thereby being capable of being widely applied and popularized.

Description

technical field [0001] The invention is a method applied to modal parameter identification, especially a method applied to parameter identification of dense modal in civil engineering structure. Background technique [0002] The wavelet change was first proposed by Moret and Grossman in the 1980s [1] , Mallat proposed the idea of ​​multi-scale analysis in 1989, and established a wavelet transform method for signal decomposition and reconstruction [2] . Daubechies [3-4] A set of orthogonal wavelets with finite support is proposed, and the relationship between wavelet analysis and discrete signal analysis is established, and has been widely used. The wavelet transform provides a variable time-frequency window that automatically narrows when analyzing high-frequency signals and automatically widens when analyzing low-frequency signals. The modal parameters contain the main characteristics of the system, and it is of great significance to accurately identify the modal parame...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/00G06K9/62
Inventor 丁幼亮孙鹏周广东李爱群宋永生
Owner SOUTHEAST UNIV
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