Identification method for stay cable vibration frequency order on basis of pseudo greatest common divisor

Abstract

The invention discloses an identification method for a stay cable vibration frequency order on the basis of a pseudo greatest common divisor and belongs to the technical field of civil engineering. The method comprises the following steps: firstly, applying axial tension to a to-be-tested cable, measuring the vibration frequency of the to-be-tested cable, and drawing an amplitude-vibration frequency curve; secondly, finding out amplitude peak values from the amplitude-vibration frequency curve, determining vibration frequency peak values corresponding to the amplitude peak values, and establishing vibration frequency peak-number arrays; thirdly, grouping the vibration frequency peak-number arrays two by two to obtain a series of subarrays only containing two vibration frequency peak-number units; fourthly, calculating the pseudo greatest common divisor of two vibration frequencies in each subarray to obtain frequency orders; dividing each vibration frequency peak value by the pseudo greatest common divisor; finally, determining accurate values of all the vibration frequency peak values corresponding to the frequency order, and rejecting error vibration frequency. According to the identification method disclosed by the invention, the frequency order can be accurately calibrated; in addition, error frequency in the frequency peak values can be rejected, and errors caused by artificial experience identification of the frequency order are reduced.

Description

technical field [0001] The invention discloses a cable vibration frequency order identification method based on pseudo-GCD and belongs to the technical field of civil engineering. Background technique [0002] The basis of the cable force identification by vibration method is the identification of the fundamental frequency and frequency of the cable. The frequency identification is obtained through the peak selection method of the self-spectrum of a single sensor or the cross-spectrum of multiple sensors, and the frequency order is usually determined by human experience. . The method of determining the frequency order by human experience naturally brings about the uncertainty of the frequency order. The factors causing the frequency order uncertainty include: [0003] First, the sensors attached to the cables often collect the vibration signals of the main structure of the bridge, such as the main girder or main cable, which makes the power spectrum naturally contain the vi...

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Problems solved by technology

[0004] Second, the signal-to-noise ratio is low when collecting data on site, and the colored noise in the environmental excitation or the vibration frequency in the vehicle load is mixed in the power spectrum;

[0005] Third, in the indoor tension test, the unreasonable design of the tooling equipment caused the vibration frequency of the cable to be not related to the cable force;

[0006] Fourth, the peak selection method itself is a frequency identification process of human intervention, so it is difficult to avoid human errors in frequency selection;

[0009] First, most cable vibration frequencies are correctly identified, but their frequency scales are not obvious enough;

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