Real-time identification and monitoring early warning method for vortex vibration event of large-span suspension bridge

A monitoring and early warning, suspension bridge technology, applied in measuring devices, measuring resonance frequency, measuring ultrasonic/sonic/infrasonic waves, etc., can solve the problems of inability to accurately perceive the occurrence and end of vortex vibration, inability to judge online in real time, and large judgment errors, etc. Achieve the effect of real-time early warning and online measurement of vortex vibration, high engineering application value, and high real-time performance

Active Publication Date: 2021-04-09

TONGJI UNIV

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AI-Extracted Technical Summary

Problems solved by technology

Based on the vortex vibration characteristics of bridges, the current bridge vortex vibration identification is mainly to identify the stable sinusoidal vibration segment in the bridge monitoring data with the naked eye, or to perform spectrum analysis on a segment of data and manually judge whether there is only a single spectru...

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Abstract

The invention discloses a real-time identification and monitoring early warning method for a vortex vibration event of a large-span suspension bridge. The method comprises the following steps: firstly, calculating a frequency spectrum of a bridge monitoring acceleration signal; determining a high-pass filtering cut-off frequency according to the bridge first-order frequency corresponding to the frequency spectrum first-order energy peak value, removing low-frequency noise interference in the signal through filtering, and calculating real-time vibration displacement of the bridge by adopting a recursive acceleration integration method; and carrying out real-time recursive Hilbert transform on the integral displacement data to obtain a real part and an imaginary part of signal data, and carrying out complex plane expression and evaluation on signals to realize vortex vibration identification and early warning. The method has the advantages of high real-time performance, high precision, accuracy and intuition; and the vibration characteristics of the bridge during vortex vibration are identified and measured online in real time, and vortex vibration early warning and online monitoring of the bridge are carried out.

Application Domain

Resonant frequency

Technology Topic

Frequency noiseReal-time computing +4

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Examples

Experimental program(1)

Example Embodiment

[0054] Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0055] figure 1 A flowchart of a method of an embodiment of the present invention is shown. like figure 1 As shown, the present invention provides a method for real-time identification, monitoring and early warning of vortex vibration events in long-span suspension bridges, using the real-time acceleration data obtained by the acceleration sensor of the real bridge health monitoring system for calculation and analysis, with a sampling frequency of 50 Hz, including the following steps:

[0056] S1: Based on the time history of the bridge acceleration monitoring signal, the spectrum is calculated by fast Fourier transform FFT, and the abscissa corresponding to the first-order energy peak of the spectrum is read to obtain the first-order frequency of the structure , and determine the filter cutoff frequency :

[0057] ;

[0058] In the formula, is the filter scale factor; for long-span bridges, Take as;

[0059] S2: Remove the low-frequency noise interference in the acceleration signal through the recursive high-pass filtering method. The form of the recursive filter is:

[0060] ;

[0061] In the formula, and are the input and output signals, respectively, is a constant close to 1;

[0062] S3: Calculate the vibration displacement of the bridge using the recursive acceleration integration method:

[0063] First, the recursive least squares method is used to correct the baseline of the bridge acceleration monitoring signal, and then the recursive high-pass filter is used to eliminate the low-frequency noise in the acceleration signal. Finally, the acceleration signal is integrated by the time domain quadratic integration method to obtain the bridge vibration displacement data;

[0064] S4: Perform short-term recursive Hilbert transform on the integral displacement data, construct the analytical signal in the complex domain, and obtain the real part and imaginary part of the signal data, and express the signal in the complex plane:

[0065] ;

[0066] In the formula, for the time domain signal Do the Hilbert transform:;

[0067] For discrete monitoring signal data, the Hilbert transform calculation formula is:

[0068] ;

[0069] In the formula, is the sampling signal;

[0070] is the signal sampling length, is the impulse response multiplier, expressed as:

[0071] ;

[0072] The real part and imaginary part of the analytical signal in the complex domain are obtained by calculation, and the real part is used as the x-axis, and the imaginary part is used as the y-axis to draw the complex plane vector image of the data; if vortex vibration occurs, the image presents a circular feature, such as Figure 2b shown; the image in the non-vortex vibration area is chaotic and irregular, such as Figure 3b Real-time identification and early warning of the generation of vortex vibration;

[0073] By directly performing short-time Hilbert transform on the real-time acceleration monitoring signal, and drawing the data complex plane vector image with the real part as the x-axis and the imaginary part as the y-axis; if vortex vibration occurs, the image presents approximately circular features, such as Figure 2a shown; the images in the non-vortex vibration area are chaotic and irregular, such as Figure 3a As shown, the generation of eddy vibration is identified and warned in real time.

[0074] The present invention also provides a real-time tracking and measuring method for vortex vibration events of a long-span suspension bridge, comprising the following steps:

[0075] 1): Real-time measurement of the vibration displacement at the current moment:

[0076] First, the recursive least squares method is used to correct the baseline of the bridge acceleration monitoring signal, and then the recursive high-pass filter is used to eliminate the low-frequency noise in the acceleration signal. Finally, the acceleration signal is integrated by the time domain quadratic integration method to obtain the bridge vibration displacement data;

[0077] 2) Calculate the instantaneous phase of bridge eddy vibration:

[0078] Based on the short-time recursive Hilbert transform of the displacement signal obtained by acceleration integration, the real part and imaginary part of the analytical signal in the complex domain are obtained, then the instantaneous phase of the vortex vibration of the bridge :

[0079] ;

[0080] 3) Calculate the instantaneous frequency of bridge eddy vibration:

[0081] Calculate the first derivative of the instantaneous phase with respect to time to obtain the instantaneous frequency during the vortex vibration of the bridge :

[0082] ;

[0083] 4) Calculate the real-time amplitude of bridge eddy vibration:

[0084] Real-time amplitude during bridge vortex vibration Calculated from the real and imaginary parts of the analytic signal in the complex domain:

[0085] ;

[0086] Realize the real-time whole-process measurement of eddy vibration.

[0087] The present invention can be used for vortex vibration monitoring and early warning of main girders and slender load-bearing components of long-span bridges such as suspension bridges and cable-stayed bridges, such as drag cables, main cables and slings, and serves as monitoring and management service for bridge owners; it can also be used for In the process monitoring of the scaled-scale model aerodynamic test and segmental aerodynamic test in the wind tunnel test room of the above-mentioned long-span bridge; it can also be used in other engineering structures that have the monitoring requirements of vortex-induced vibration in the cross-wind direction, such as long-span cable-membrane structures, cable , towers, high-rise buildings, etc.

[0088] The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

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Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

High engineering application value
Easy to implement

Five-axis numerical control machine tool planar processing process ball-end cutter and workpiece contact area semi-analytic modeling method

ActiveCN107544433AHigh engineering application valueProgramme controlComputer controlDistribution characteristicMachining process

Owner:DALIAN UNIV OF TECH

Real-time identification and monitoring early warning method for vortex vibration event of large-span suspension bridge

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

PUM

Description & Claims & Application Information

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