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A fitting method of lamb wave spatial sampling signal based on morlet mother wavelet

A space sampling and signal technology, applied in pattern recognition, instruments, and complex mathematical operations in signals, can solve the problem of limited spatial resolution and length of Lamb wave spatial signals, affecting space-wavenumber domain signal processing methods, and damage monitoring errors and other problems, to achieve the effect of reducing the number of layouts, improving spatial resolution, and reducing damage monitoring errors

Inactive Publication Date: 2020-04-17
中国人民解放军空军勤务学院
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AI Technical Summary

Problems solved by technology

Among them, many scholars use scanning laser Doppler vibrometer to collect the spatial fluctuation information of Lamb wave propagation in the structure, which is difficult for online monitoring of structural damage
Some scholars use piezoelectric sensor arrays to collect Lamb wave spatial fluctuation information for online monitoring, which is limited by the size and structure of piezoelectric sensors. The spatial resolution and length of the Lamb wave spatial signals collected in this way are limited. Seriously affected the subsequent space-wavenumber domain signal processing method, resulting in larger damage monitoring errors

Method used

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  • A fitting method of lamb wave spatial sampling signal based on morlet mother wavelet
  • A fitting method of lamb wave spatial sampling signal based on morlet mother wavelet
  • A fitting method of lamb wave spatial sampling signal based on morlet mother wavelet

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Experimental program
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Effect test

Embodiment

[0048] Embodiment comprises the steps:

[0049] Step 1: Initialize settings

[0050] ①Set the center frequency of the Morlet mother wavelet as c=1Hz, the sampling frequency as d=50Hz, the sampling time as t=[-70,70], and the sampling time resolution as Δt=1 / d.

[0051] ②According to the number of peaks of the Lamb wave excitation signal (sinusoidally modulated five-peak narrow-band signal, n=5), use the formula (1) to construct the corresponding Lamb wave excitation simulation signal s 1 , the center frequency of the simulated signal is c 1 =c=1Hz, the sampling frequency is d 1 =d=50Hz, sampling time is t 1 =t=[-70,70], such as Figure 4 shown.

[0052]

[0053] In the formula: c 1 is the center frequency of the Lamb wave excitation simulation signal, t 1 is the sampling time of the Lamb wave excitation simulation signal, n is the peak number of the Lamb wave excitation simulation signal, and π is the circumference ratio.

[0054] Step 2: Calculate the bandwidth par...

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Abstract

The invention discloses a Lamb wave spatial sampling signal fitting method based on a Morlet mother wavelet, and belongs to the technical field of engineering structure health monitoring. This method first sets the center frequency, sampling frequency, and sampling time of the Morlet mother wavelet; then constructs the Lamb wave excitation simulation signal according to the number of Lamb wave excitation signal peaks; secondly, according to the Morlet mother wavelet fitting waveform and Lamb wave Excite the correlation coefficient of the simulated signal to obtain the frequency bandwidth parameter of the Morlet mother wavelet; finally, according to the error sum of the squares of the Morlet wavelet function fitting waveform and the Lamb wave spatial sampling signal under different scale factors and displacement factors, obtain the Morlet wavelet function approximation At this time, the corresponding Morlet wavelet function fitting waveform is the Morlet wavelet function fitting waveform of the Lamb wave spatial sampling signal. The invention improves the spatial resolution and length of the Lamb wave spatial sampling signal, thereby helping to promote the application of the space-wavenumber domain signal processing method in the field of engineering structure health monitoring.

Description

technical field [0001] The invention relates to a Lamb wave spatial sampling signal fitting method based on a Morlet mother wavelet, and belongs to the technical field of engineering structure health monitoring. Background technique [0002] The structural health monitoring method based on Lamb waves has the advantages of high damage monitoring sensitivity, large monitoring range, online application and offline application, active damage monitoring and passive impact monitoring, and monitoring of metal structures and composite materials. structure and so on. Therefore, the structural health monitoring method based on Lamb waves has been widely studied at home and abroad, and it is one of the most promising structural health monitoring technologies at present. Usually, the piezoelectric sensor is the main device to realize Lamb wave excitation and sensing. For the structural health monitoring method based on Lamb wave, the early method is mainly through the analysis of the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06K9/00G06F17/15
CPCG06F17/15G06F2218/14G06F2218/10
Inventor 刘彬孟凡芹胡建强耿光辉陈利安王文娟贾丽赵鹏程校云鹏马军
Owner 中国人民解放军空军勤务学院
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