Cable system bridge cable member vibration frequency automatic identification method

Abstract

The application discloses a kind of cable system bridge cable member vibration frequency automatic identification method.Belongs to structure inspection, monitoring field, specific operation steps are as follows: (1), obtain cable member vibration monitoring data;(2), get power spectrum envelope density;(3), form power spectrum envelope maximum value frequency array and power spectrum envelope maximum value array, and then get optimized power spectrum envelope maximum value frequency array and optimized power spectrum envelope maximum value array;(4), obtain fundamental frequency array and nominal fundamental frequency;(5), based on Fourier transform, obtain the frequency array and power array of the frequency spectrum of vibration data, and calculate the frequency of each order of cable member;(6), calculate cable force value and draw frequency automatic identification chart.The application can automatically calculate and analyze the vibration fundamental frequency and each order natural frequency of cable system bridge cable member, effectively improve the efficiency of cable force inspection and monitoring by spectrum method, reduce error, and provide technical support for structure safety evaluation.

Description

Technical Field

[0001] The invention belongs to the field of structure inspection and monitoring, and relates to a method for automatically identifying the vibration frequency of a cable member of a bridge in a cable system. Background Art

[0002] Cable components are important load-bearing components of bridge structures. The magnitude of their cable forces is directly related to the stress and deformation of the overall bridge structure. Therefore, automatically and accurately obtaining cable force values ​​is of great significance for bridge safety assessment and technical status evaluation. In the existing technology, the fundamental frequency method is a commonly used method for cable force analysis in the field of bridge structure inspection and monitoring. However, in engineering practice, the fundamental frequency of cable component vibration is difficult to identify intelligently through program automation. Professional engineers are required to conduct special analysis of cable component vibration data and manually identify the various frequencies of cable components. On the one hand, this affects the efficiency of cable force calculation inspection and monitoring; on the other hand, there are subjective factors of personnel, and frequency identification will have certain errors or errors. Therefore, the automatic identification of the fundamental frequency and various frequencies of cable components is of great significance for accurately analyzing cable forces and improving the efficiency of cable force inspection and monitoring. Summary of the Invention

[0003] Purpose of the Invention: This invention provides a method for automatically identifying the vibration frequencies of cable-type bridge cable members. This method can be used to automatically identify the natural frequencies of each cable member. This method is crucial for accurately and efficiently identifying the fundamental frequencies of cable-type bridge cable members. Furthermore, this method offers advantages such as high efficiency and excellent noise immunity, making it suitable for widespread engineering application.

[0004] Technical solution: The method for automatically identifying the vibration frequency of cable components of a cable system bridge according to the present invention has the following specific operating steps:

[0005] Step (1), obtaining cable component vibration monitoring data;

[0006] Step (2), performing power spectrum analysis on the obtained cable member vibration monitoring data to obtain a power spectrum envelope density;

[0007] Step (3), searching for the maximum points of the power spectrum envelope density in sequence, forming a power spectrum envelope maximum frequency array and a power spectrum envelope maximum array;

[0008] Step (4), obtaining a fundamental frequency array and a nominal fundamental frequency by performing first-order difference on the maximum frequency number of the optimized power spectrum envelope;

[0009] Step (5), based on Fourier transform, obtaining the spectrum frequency array and power array of the vibration data;

[0010] Step (6): Calculate the cable force value and draw the frequency automatic recognition diagram.

[0011] Furthermore, in step (1), in obtaining the cable member vibration monitoring data,

[0012] The cable component vibration monitoring data is D i ,

[0013] Where i=1,2,,N, is the vibration data position; N is the number of vibration data.

[0014] Furthermore, in step (2), the power spectrum analysis is performed on the obtained cable member vibration monitoring data to obtain the power spectrum envelope density. The specific method is:

[0015] The vibration data D i Divided into K segments, each segment vibration data is D k,j ;

[0016] Where k = 1, 2, K, is the number of segments; j = 1, 2, J, is the number of monitoring data for each segment, J = N / K;

[0017] The power spectrum pwtlch function is used to perform power spectrum analysis on the vibration data of each section to obtain the power spectrum frequency array F g And the power spectral density array P k,g , g is the data position of the power spectrum frequency array;

[0018] The power spectrum density array P of each segment k,g Accumulate and sum the corresponding frequency components to obtain the power spectrum envelope density

[0019] Furthermore, in step (3), after forming the power spectrum envelope maximum frequency array and the power spectrum envelope maximum array, the optimized power spectrum envelope maximum frequency array and the optimized power spectrum envelope maximum array are obtained.

[0020] Furthermore, the specific method of finding and calculating the maximum point of the power spectrum envelope is:

[0021] Starting from g=1, search for the power spectrum envelope density P g The maximum point of P g+1 <P g , then record the location g, forming the power spectrum envelope maximum point location array G l , l=1,2,,L, is the maximum position, L is the number of maximum points; then the power spectrum envelope maximum frequency array is The power spectrum envelope maximum array is

[0022] Among them, the power spectrum envelope maximum array The maximum value is

[0023] Calculate the power spectrum envelope maximum array Less than the maximum value 1 / 10 of the data position, the power spectrum envelope maximum array of the corresponding position and the power spectrum envelope maximum frequency array The values ​​in are replaced with null values, recorded as the optimized power spectrum envelope maximum array and optimize the power spectrum envelope maximum frequency array

[0024] Furthermore, in step (4), the specific method of obtaining the fundamental frequency array and the nominal fundamental frequency is:

[0025] Optimize the power spectrum envelope maximum frequency array Do the first-order difference to get the fundamental frequency array Calculate the mean of the fundamental frequency array to obtain the nominal fundamental frequency f1.

[0026] Furthermore, in step (5), the specific method of obtaining the spectrum frequency array and power array of the vibration data is:

[0027] Calculate vibration data D based on Fourier transform i The spectrum of the spectrum is obtained to obtain the spectrum frequency array F1 and power array P1, where the maximum value of the power array is recorded as P1 max =max(P1).

[0028] Furthermore, in step (5), after obtaining the spectrum frequency array and power array of the vibration data, the frequency domain interval is divided by the nominal fundamental frequency, and the frequencies of each order of the cable component are calculated.

[0029] Furthermore, the specific method of calculating the frequencies of the cable components is:

[0030] Based on the spectrum frequency array F1 obtained by Fourier transform, [n×(f1-f1 / 2), n×(f1+f1 / 2)] is used as the segment, and the frequency position of the maximum value in each segment power array P1 is calculated, which is recorded as the frequency array f of each order. n , the corresponding power spectrum is n is the frequency order.

[0031] Furthermore, in step (6), the specific method of calculating the cable force value and drawing the frequency automatic identification diagram is:

[0032] Cable force value Where, λ is the cable tension coefficient;

[0033] Calculate the maximum value in the power spectrum envelope maximum array With the maximum value of the power array P1max Ratio Multiply the power array P1 by the ratio μ to obtain the unified power array P1 统一 , respectively, with spectrum frequency array F1 and power spectrum frequency array F g , frequency arrays of each order f n As the independent variable, the unified power array P1 统一 , power spectrum envelope density P g , power spectrum As the dependent variable, draw the frequency automatic recognition diagram.

[0034] Beneficial effects: Compared with the prior art, the characteristics of the present invention are: 1. This method can be used to efficiently and accurately calculate the natural frequencies of various orders of cable components in cable system bridges, automatically analyze and identify the fundamental frequencies of cable components, and is of great significance for rapid detection and monitoring of cable forces using the vibration method; 2. This method has been implemented in a programmed manner, is simple and quick to operate, and has wide engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is an operational flow chart of the present invention;

[0036] Figure 2 This is a structural diagram of the bridge facade in an embodiment of the present invention;

[0037] Figure 3 is a structural diagram of a vibration data time history according to an embodiment of the present invention;

[0038] Figure 4 is a structural diagram of the power spectrum envelope of vibration data in an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the power spectrum envelope and the maximum value of the power spectrum envelope of vibration data in an embodiment of the present invention. Figure 1 ;

[0040] Figure 6 This is a schematic diagram of the power spectrum envelope and the maximum value of the power spectrum envelope of vibration data in an embodiment of the present invention. Figure 2 ;

[0041] Figure 7 is a structural diagram of a vibration data spectrum according to an embodiment of the present invention;

[0042] Figure 8 4 is a structural diagram of automatic frequency recognition in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to more clearly illustrate the technical solution of the present invention, the technical solution of the present invention is further described in detail below with reference to the accompanying drawings:

[0044] As shown in the figure, the specific operating steps of the automatic identification method of the vibration frequency of the cable system bridge cable member of the present invention are as follows:

[0045] Step (1), obtaining cable component vibration monitoring data;

[0046] Step (2), performing power spectrum analysis on the vibration data to obtain the power spectrum envelope density;

[0047] Step (3), searching for the maximum points of the power spectrum envelope density in sequence, forming a power spectrum envelope maximum frequency array and a power spectrum envelope maximum array, and then obtaining an optimized power spectrum envelope maximum frequency array and an optimized power spectrum envelope maximum array;

[0048] Step (4), obtaining a fundamental frequency array and a nominal fundamental frequency by performing first-order difference on the maximum frequency number of the optimized power spectrum envelope;

[0049] Step (5), based on Fourier transform, obtain the spectrum frequency array and power array of the vibration data, divide the frequency domain interval by the nominal fundamental frequency, and calculate the frequency of each order of the cable component;

[0050] Step (6): Calculate the cable force value and draw the frequency automatic recognition diagram.

[0051] The present invention realizes the automatic intelligent recognition of the vibration frequency of the cable component, improves the working efficiency of cable force detection and monitoring, and significantly reduces the error existing in the manual recognition method.

[0052] Furthermore, in step (1), the vibration data of the cable member is D i ,

[0053] Where i=1, 2, ..., N is the position of the vibration data, and N is the number of vibration data.

[0054] Furthermore, in step (2), the calculation of the power spectrum envelope of the vibration data is specifically:

[0055] The vibration data D i Divided into K segments, each segment vibration data is D k,j , k=1,2,...,K is the number of segments, j=1,2,...,J is the number of monitoring data in each segment, J=N / K;

[0056] The power spectrum pwtlch function is used to perform power spectrum analysis on the vibration data of each section to obtain the power spectrum frequency array F g And the power spectral density array P k,g , g is the data position of the power spectrum frequency array;

[0057] The power spectrum density array P of each segment k,gAccumulate and sum the corresponding frequency components to obtain the power spectrum envelope density

[0058] Furthermore, in step (3), the method of finding and calculating the maximum value point of the power spectrum envelope is as follows:

[0059] Starting from g=1, search for the power spectrum envelope density P g The maximum point of P g+1 <P g , then record the location g, forming the power spectrum envelope maximum point location array G l , l=1,2,...,L is the maximum position, L is the number of maximum points; then the power spectrum envelope maximum frequency array is The power spectrum envelope maximum array is Among them, the power spectrum envelope maximum array The maximum value is

[0060] Calculate the power spectrum envelope maximum array Less than the maximum value 1 / 10 of the data position, the power spectrum envelope maximum array of the corresponding position and the power spectrum envelope maximum frequency array The values ​​in are replaced with null values, recorded as the optimized power spectrum envelope maximum array and optimize the power spectrum envelope maximum frequency array

[0061] Furthermore, in step (4), the calculation of the nominal fundamental frequency is specifically:

[0062] Optimize the power spectrum envelope maximum frequency array Do the first-order difference to get the fundamental frequency array Calculate the mean of the fundamental frequency array to obtain the nominal fundamental frequency f1.

[0063] Furthermore, in step (5), the vibration data spectrum is analyzed, and the frequency domain interval is divided by the nominal fundamental frequency, and the frequencies of each order of the cable component are calculated specifically as follows:

[0064] Calculate vibration data D based on Fourier transform i The spectrum of the spectrum is obtained to obtain the spectrum frequency array F1 and power array P1, where the maximum value of the power array is recorded as P1 max =max(P1);

[0065] Based on the spectrum frequency array F1 obtained by Fourier transform, [n×(f1-f1 / 2), n×(f1+f1 / 2)] is used as the segment, and the frequency position of the maximum value in each segment power array P1 is calculated, which is recorded as the frequency array f of each order.n , the corresponding power spectrum is n is the frequency order.

[0066] Furthermore, in step (6), the calculation of the cable force value and the drawing of the frequency automatic identification diagram are specifically:

[0067] Cable force value Where, λ is the cable tension coefficient;

[0068] Calculate the maximum value in the power spectrum envelope maximum array With the maximum value of the power array P1 max Ratio Multiply the power array P1 by the ratio μ to obtain the unified power array P1 统一 , respectively, with spectrum frequency array F1 and power spectrum frequency array F g , frequency arrays of each order f n As the independent variable, the unified power array P1 统一 , power spectrum envelope density P g , power spectrum As the dependent variable, draw the frequency automatic recognition diagram.

[0069] Example:

[0070] The span arrangement of a certain super-large bridge is as follows: 4 spans of 40.7m prestressed concrete simply supported box girders + (54.2+2×80+54.2)m prestressed concrete continuous box girders + 62 spans of 40.7m prestressed concrete simply supported box girders + (98+196+504+196+98)m five-span single-unit steel truss cable-stayed bridge + 15 spans of 40.7m prestressed concrete simply supported box girders, with a total length of 4657.1m.

[0071] The main span is a dual-tower, three-truss, three-cable-plane steel truss cable-stayed bridge for both highway and railway use. The upper chord is a highway deck and the lower chord is a railway deck. The bridge is 1,092 meters long. The main tower is an inverted "Y"-shaped concrete structure with a height of 188.5 meters. The tower column is a hollow rectangular section. The cables are made of parallel galvanized high-strength steel wire and double-layer PE cold-cast anchors. The main truss spans 14 meters, the truss width is 30 meters, and the truss height is 14.5 meters. The bridge facade is as follows: Figure 2 As shown;

[0072] Taking the vibration data of the bridge's stay cables during a certain period as an example, this paper analyzes the automatic vibration frequency identification method for cable-stayed bridge components. The specific steps are as follows:

[0073] First, obtain the vibration monitoring data of the cable component, and record the vibration data of the inclined cable (hereinafter referred to as: vibration data) as D i , i=1,2,...,N is the vibration data position, N=15360 is the number of vibration data, and the vibration monitoring data time course is as follows Figure 3 As shown;

[0074] Then the vibration data D i Divided into K=30 segments, the vibration data of each segment is D k,j , k=1,2,...,K is the number of sections, j=1,2,...,J is the number of monitoring data for each section, J=N / K=512, use the power spectrum pwtlch function to perform power spectrum analysis on the vibration data of each section, and get the power spectrum frequency array F g And the power spectral density array P k,g , g is the data position of the power spectrum frequency array, and the power spectrum density array P of each segment k,g Accumulate and sum the corresponding frequency components to obtain the power spectrum envelope density The power spectrum envelope is shown as Figure 4 As shown;

[0075] Then start from g=1 and search the power spectrum envelope density P g The maximum point of P g+1 <P g , then record the location g, forming the power spectrum envelope maximum point location array G l , l=1,2,...,L is the maximum position, L is the number of maximum points, then the power spectrum envelope maximum frequency array is The power spectrum envelope maximum array is Among them, the power spectrum envelope maximum array The maximum value is The power spectrum envelope and the maximum value of the power spectrum envelope of vibration data are as follows: Figure 5 As shown;

[0076] Calculate the power spectrum envelope maximum array Less than the maximum value 1 / 10 of the data position, the power spectrum envelope maximum array of the corresponding position And the power spectrum envelope maximum frequency array F Gl The values ​​in are replaced with null values, recorded as the optimized power spectrum envelope maximum array and optimize the power spectrum envelope maximum frequency array After replacing with null values, the power spectrum envelope and the maximum value of the power spectrum envelope of the vibration data are as follows: Figure 6 As shown;

[0077] Optimize the power spectrum envelope maximum frequency array Do the first-order difference to get the fundamental frequency array Calculate the mean value of the fundamental frequency array to obtain the nominal fundamental frequency f1 = 0.55;

[0078] Calculate vibration data D based on Fourier transform iThe spectrum of the spectrum is obtained to obtain the spectrum frequency array F1 and power array P1, where the maximum value of the power array is recorded as P1 max =max(P1), the spectrum of the vibration data is as follows Figure 7 As shown;

[0079] Then, based on the spectrum frequency array F1, with [n×(f1-f1 / 2), n×(f1+f1 / 2)] as the segment, calculate the frequency position of the maximum value in each segment power array P1, which is recorded as the frequency array f of each order n , the corresponding power spectrum is n is the frequency order;

[0080] Calculate the cable force T = λ × f1 2 , where λ is the cable tension coefficient, and then calculate the maximum value in the power spectrum envelope maximum array With the maximum value of the power array P1 max Ratio Multiply the power array P1 by the ratio μ to obtain the unified power array P1 统一 , respectively, with spectrum frequency array F1 and power spectrum frequency array F g , frequency arrays of each order f n As the independent variable, the unified power array P1 统一 , power spectrum envelope density P g , power spectrum As the dependent variable, draw the frequency automatic recognition diagram, such as Figure 8 shown.

[0081] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for automatically identifying the vibration frequency of cable members of a cable system bridge, characterized in that: The specific steps are as follows: Step (1), obtaining cable component vibration monitoring data; Step (2), performing power spectrum analysis on the obtained cable member vibration monitoring data to obtain a power spectrum envelope density; Step (3), searching for the maximum points of the power spectrum envelope density in sequence, forming a power spectrum envelope maximum frequency array and a power spectrum envelope maximum array; Step (4), obtaining a fundamental frequency array and a nominal fundamental frequency by performing first-order difference on the maximum frequency array of the optimized power spectrum envelope; Step (5), based on Fourier transform, obtaining the spectrum frequency array and power array of the vibration data; Among them, after obtaining the spectrum frequency array and power array of the vibration data, the frequency domain interval is divided by the nominal fundamental frequency to calculate the frequency of each order of the cable component; The specific method for calculating the frequencies of each order of cable components is: Based on the spectrum frequency array F1 obtained by Fourier transform, [n×(f1-f1 / 2), n×(f1+f1 / 2)] is used as the segment, and the frequency position of the maximum value in each segment power array P1 is calculated, which is recorded as the frequency array f of each order. n , the corresponding power spectrum is n is the frequency order; Step (6), calculating the cable force value and drawing the frequency automatic identification diagram; the specific method is: Cable force T = λ × f1 2 , where λ is the cable tension coefficient; Calculate the maximum value in the power spectrum envelope maximum array With the maximum value of the power array P1 max Ratio Multiply the power array P1 by the ratio μ to obtain the unified power array P1 统一 , respectively, with spectrum frequency array F1 and power spectrum frequency array F g , frequency arrays of each order f n As the independent variable, the unified power array P1 统一 , power spectrum envelope density P g , power spectrum As the dependent variable, draw the frequency automatic recognition diagram.

2. The method for automatically identifying the vibration frequency of a cable-type bridge member according to claim 1, characterized in that: In step (1), in obtaining the cable member vibration monitoring data, The cable component vibration monitoring data is D i , Wherein, i=1, 2, ..., N, is the position of the vibration data; N is the number of vibration data.

3. The method for automatically identifying the vibration frequency of a cable-type bridge member according to claim 1, characterized in that: In step (2), the power spectrum analysis of the obtained cable member vibration monitoring data is performed to obtain the power spectrum envelope density. The specific method is: The vibration data D i Divided into K segments, each segment vibration data is D k,j ; Where k = 1, 2, ..., K, is the number of segments; j = 1, 2, ..., J, is the number of monitoring data for each segment, J = N / K; The power spectrum pwtlch function is used to perform power spectrum analysis on the vibration data of each section to obtain the power spectrum frequency array F g And the power spectral density array P k,g , g is the data position of the power spectrum frequency array; The power spectrum density array P of each segment k,g Accumulate and sum the corresponding frequency components to obtain the power spectrum envelope density 4. The method for automatically identifying vibration frequencies of cable-type bridge components according to claim 1, characterized in that: In step (3), after forming the power spectrum envelope maximum frequency array and the power spectrum envelope maximum array, the optimized power spectrum envelope maximum frequency array and the optimized power spectrum envelope maximum array are obtained.

5. The method for automatically identifying the vibration frequency of a cable-type bridge member according to claim 4, characterized in that: The specific method of finding and calculating the maximum value point of the power spectrum envelope is: Starting from g=1, search for the power spectrum envelope density P g The maximum point of P g+1 <P g , then record the location g, forming the power spectrum envelope maximum point location array G l , l=1,2,...,L, is the maximum position, L is the number of maximum points; then the power spectrum envelope maximum frequency array is The power spectrum envelope maximum array is Among them, the power spectrum envelope maximum array The maximum value is Calculate the power spectrum envelope maximum array Less than the maximum value 1 / 10 of the data position, the power spectrum envelope maximum array of the corresponding position and the power spectrum envelope maximum frequency array The values ​​in are replaced with null values, recorded as the optimized power spectrum envelope maximum array and optimize the power spectrum envelope maximum frequency array 6. The method for automatically identifying vibration frequencies of cable-type bridge components according to claim 1, characterized in that: In step (4), the specific method of obtaining the fundamental frequency array and the nominal fundamental frequency is: Optimize the power spectrum envelope maximum frequency array Do the first-order difference to get the fundamental frequency array Calculate the mean of the fundamental frequency array to obtain the nominal fundamental frequency f1.

7. The method for automatically identifying vibration frequencies of cable-type bridge members according to claim 1, characterized in that: In step (5), the specific method of obtaining the spectrum frequency array and power array of the vibration data is: Calculate vibration data D based on Fourier transform i The spectrum of the spectrum is obtained to obtain the spectrum frequency array F1 and power array P1, where the maximum value of the power array is recorded as P1 max =max(P1).

Images