A referenceless method for identifying the location of defects in pipe structures based on multi-frequency helical waveguides.

Abstract

This invention relates to the field of pipeline structural defect identification technology, and in particular provides a referenceless method for identifying pipeline structural defects based on multi-frequency helical guided waves. The method includes constructing a pipeline structural defect detection system and grouping sensor paths; calculating a difference signal set based on the defect helical guided wave signals acquired by a piezoelectric sensor array according to the sensor path grouping; determining a defect factor based on the correlation coefficient between the difference signals to filter and obtain effective defect paths; and identifying the pipeline structural defect location by fusing the defect existence probabilities of different excitation frequencies based on the effective defect paths. This method achieves adaptive defect path filtering, improving the accuracy and reliability of defect localization.

Description

Technical Field

[0001] This invention relates to the field of pipeline structural defect identification technology, and in particular to a non-reference-based method for identifying the location of pipeline structural defects based on multi-frequency spiral guided waves. Background Technology

[0002] Pipeline structures are widely used in industries such as petroleum, chemical, water supply, and gas. Their structural health directly affects production safety and operational efficiency. Because pipelines operate under complex conditions such as high pressure, corrosion, and fatigue for extended periods, they are prone to defects such as cracks, corrosion, and deformation. Therefore, regular defect inspection of pipelines is crucial.

[0003] Currently, common pipeline defect detection methods include visual inspection, ultrasonic inspection, magnetic flux leakage inspection, X-ray inspection, and guided wave-based inspection technology. Among them, ultrasonic guided wave inspection is widely used in non-destructive testing of pipeline structures due to its advantages such as long propagation distance, wide coverage, and high detection efficiency. Existing technologies have the following disadvantages: (1) Reliance on reference signal: Traditional ultrasonic guided wave inspection methods usually need to be compared with a reference signal in a defect-free state to identify defects. However, in actual engineering, it is often difficult to obtain a defect-free reference signal, especially after the pipeline is put into use or when historical data is missing, the applicability of this method is limited; (2) Low defect location accuracy: Existing methods mostly rely on guided wave signals of a single frequency or a single path, and the judgment of defect location is easily affected by factors such as noise and material inhomogeneity, resulting in inaccurate location; (3) Path selection depends on experience: In the existing technology, the selection of effective sensing paths mostly depends on human experience or fixed thresholds, lacking an adaptive path selection mechanism, which is prone to missed detection or false detection; (4) Poor system robustness: Due to the lack of a multi-frequency data fusion mechanism, the existing methods are poorly adaptable to different defect types or different working conditions, and the detection results are unstable. Summary of the Invention

[0004] In view of this, the present invention provides a referenceless identification method for pipeline structural defect location based on multi-frequency spiral guided waves, which can realize adaptive screening of defect paths and improve the accuracy and reliability of defect location.

[0005] In a first aspect, the present invention provides a referenceless method for identifying the location of defects in pipe structures based on multi-frequency helical guided waves, the method comprising:

[0006] Step 1: Construct a pipeline structural defect detection system and group the sensor paths;

[0007] Step 2: Group the signals according to the sensing path, and calculate the difference signal set based on the defective spiral guided wave signals collected by the piezoelectric sensing array;

[0008] Step 3: Based on the correlation coefficient between the difference signals, determine the defect factors to screen and obtain effective defect paths;

[0009] Step 4: Based on the effective defect path, integrate the probability of defect existence under different excitation frequencies to identify the location of pipeline structural defects.

[0010] Optionally, step 1 includes:

[0011] Step 11: Composition of the defect detection system;

[0012] A defect detection system for a pipeline structure is built using a host computer, an ultrasonic guided wave detection device, a piezoelectric sensor array, and a pipeline structure: (1) The host computer is connected to the ultrasonic guided wave detection device, and data is transmitted bidirectionally between the two. The host computer is used to set the ultrasonic guided wave excitation signal parameters and ultrasonic guided wave receiving signal parameters. (2) One end of the ultrasonic guided wave detection device is connected to the host computer, and the other end is connected to the piezoelectric sensor. The ultrasonic guided wave detection device is used to generate ultrasonic guided waves based on the ultrasonic guided wave excitation signal parameters set by the host computer, and transmit them to the excitation sensor in the piezoelectric sensor array. It is also used to extract the guided wave signal received by the receiving sensor in the piezoelectric sensor array, and filter and store it according to the ultrasonic guided wave receiving signal parameters set by the host computer. (3) The piezoelectric sensor array consists of 2N piezoelectric ceramic sensors. Among them, N sensors are used as excitation sensors to convert the electrical signal emitted by the ultrasonic guided wave detection device into a stress signal. Then, the stress signal will propagate outward in a circular pattern on the surface of the pipeline structure to form a spiral guided wave. The other N sensors are used as receiving sensors to convert the stress signal propagating along the surface of the pipeline structure into an electrical signal.

[0013] Step 12: Arrangement of piezoelectric sensor array;

[0014] The arrangement and naming conventions for piezoelectric sensor arrays are as follows:

[0015] A sensor array consisting of N excitation sensors is called an excitation sensing array, denoted as A1, A2, ..., A N A sensor array consisting of N receiving sensors is called a receiving sensor array, denoted as R1, R2, ..., R3. N ;

[0016] Both the excitation sensor array plane and the receiving sensor array plane are perpendicular to the central axis of the pipe structure, and are uniformly pasted on the outer surface of the pipe structure with equal arc lengths; that is, if the outer radius of the pipe structure is r, then the adjacent excitation sensor A i' A i'+1 Or receive sensor R i' R i'+1 The arc length between them is 2πr / N, 1≤i'≤N-1; excitation sensor A i With receiving sensor Ri The straight-line distance between them is D, that is: the line connecting the excitation sensor and the receiving sensor with the same number i is parallel to the central axis of the pipe structure, 1≤i≤N;

[0017] Step 13: Grouping sensor paths;

[0018] The line segment connecting the excitation sensor and the receiving sensor in a clockwise direction along the surface of the pipe structure is called the sensing path. Therefore, for a sensing array consisting of N excitation sensors and N receiving sensors, there are a total of N... 2 A sensing path, denoted by the symbol P i→j Representative excitation sensor A i With receiving sensor R j The sensing paths between them are 1≤i≤N, 1≤j≤N;

[0019] Based on the length of the sensing path, all sensing paths are divided into N groups, and each group is represented by a P-type sensor. 1 PP 2 ... PP N This indicates that each group contains N sensing paths, which are: PP 1 ={P1 1 P2 1 , ..., P N-1 1 P N 1};PP 2 ={P1 2 P2 2 , ..., P N-1 2 P N 2};…;PP N ={P1 N P2 N , ..., P N-1 N P N N}; where path group PP j The i-th sensing path P in i j This refers to: Excitation sensor A i With receiving sensor R u The corresponding sensing path, where R u To R i The counterclockwise circumferential distance is In the formula, r is the outer radius of the pipe structure, and N is the number of excitation sensors or receiving sensors;

[0020] Based on the arrangement of the excitation sensor array and the receiving sensor array on the surface of the pipe structure, PP 1The group contains the shortest sensing path distance, valued as D, which is the straight-line distance along the axial direction of the pipe structure between the excitation sensing array plane and the receiving sensing array plane; PP N The group contains the longest sensing path distance, with a value of In the formula, r is the outer radius of the pipe structure, and N is the number of excitation sensors or receiving sensors.

[0021] Optionally, step 2 includes:

[0022] Step 21: Group and name the defect ultrasonic guided wave signals W collected by the piezoelectric sensing array;

[0023] Let W represent the guided wave signal acquired by the sensor array under the condition of a pipe structure defect, i.e., the defect spiral guided wave signal; according to the definition of the sensor path group, W is expressed as W={W 1 W 2 ,…,W N}, where the guided wave signal corresponding to the k-th path group is W. k ={W1 k W2 k ,…,W N-1 k W N k}, where W i k Indicates the sensing path P i k The corresponding guided wave signal, i.e., when sensor A is excited. i When transmitting ultrasonic guided wave signals as a signal source, the defective helical guided wave signals received by the receiving sensor on the current path are 1≤k≤N;

[0024] If M represents the number of sampling points in the ultrasonic guided wave testing device, then the guided wave signal W i k The dimension is M×1, and the signal set W k The dimension is M×N;

[0025] Step 22: Calculate the difference signal S between the ultrasonic guided wave signals of defects within each path group. k ;

[0026] Based on the defective helical waveguide signal W acquired by the sensor array, the difference signal S={S 1 S 2 S N}, where the difference signal set S corresponding to the k-th path group k ={S1 k S2 k S N-1 k S Nk}, 1≤k≤N, where S i k This indicates that within the k-th path group, excluding path P... i k External path P j k The corresponding defective guided wave signal W j k With path P i k The corresponding defective helical waveguide signal W i k The difference signal set, i.e., S i k Represented as S i k ={S i,1 k S i,2 k S i,N-1 k S i,N k}, where the j-th element S i,j k =W j k -W i k , 1≤i≤N, 1≤j≤N, and j≠i;

[0027] If M represents the number of sampling points in the ultrasonic guided wave testing device, then the difference signal S i,j k The dimension is M×1, and the difference signal set S i k The dimension is M×(N-1), and the difference signal set S k The dimension is M×(N-1)×N.

[0028] Optionally, step 3 includes:

[0029] Step 31: Calculate the correlation coefficient between the difference signals;

[0030] Computation and Sensing Path P i k The corresponding difference signal set S i k The correlation coefficient between any two signals is expressed as follows:

[0031] ;

[0032] in, Indicates the difference signal and The correlation coefficient between them, where 1 ≤ m < n ≤ N, and m ≠ i, n ≠ i, m ≠ n; represents the signal and the covariance between them, and respectively represent the standard deviations of the signals and ;

[0033] According to the grouping situation of the sensing paths and the definition of the correlation coefficient between the difference signals, based on the difference signal set S i k , calculate to obtain correlation coefficients, which are denoted as:

[0034] ;

[0035] Step 32: Define the defect factor of the sensing path;

[0036] For the i-th path P i k in the k-th path group, calculate its defect factor , and its expression is:

[0037] ;

[0038] Among them, and respectively represent the mean and variance of the correlation coefficient vector ;

[0039] For the k-th path group, its corresponding defect factor set is d k =[d1 k , d2 k , … d N k ;

[0040] Step 33: Screen to obtain the effective defect path P valid ;

[0041] For each path group, set different defect factor thresholds = 10 × min(d k ), where min(d k ) represents the minimum value of the defect factor set d k ;

[0042] Identify the sensing paths with defect factors greater than the threshold as the effective defect paths P valid ={{P valid 1}}, {{P valid 2},…,{P valid N}}, where P valid k This indicates that within the k-th path group, the defect factor is greater than the threshold. The set of sensing paths; if there is no path in the k-th path group that is greater than the threshold. If the defect factor is P, then P valid k It is an empty set.

[0043] Optionally, step 4 includes:

[0044] Step 41: Calculate the probability of a defect existing at any position (x, y);

[0045] The defect detection area of ​​the pipeline structure is unfolded along the axial direction into a two-dimensional rectangular plane of size D×2πr, where D is the straight-line distance between the excitation sensor array plane and the receiving sensor array plane along the axial direction of the pipeline structure, and r is the outer radius of the pipeline structure. Then, the probability of the presence of a defect at any position (x, y) within the detection area is G. xy for:

[0046] ;

[0047] in, Let (x, y) represent the probability that a defect exists at (x, y) on a valid defect path p. That is, the probability of a defect at (x, y) is equal to the sum of the probabilities of a defect existing on all valid defect paths, where p ∈ P. valid ;

[0048] The expression is:

[0049] ;

[0050] in, This indicates the actual arrival time of the defect guided wave signal on the effective defect path p; This represents the theoretical arrival time of the guided wave signal received by the effective defect path p at the defect location if (x,y) is the defect location. This represents the time threshold, which is numerically equal to twice the period of the guided wave signal;

[0051] Step 42: Combine different excitation frequencies to calculate the location of defects in the pipeline structure;

[0052] Collect q defect guided wave signals at different frequencies, and calculate the difference signal set, defect factor, effective defect path set, and defect existence probability at different frequencies in sequence;

[0053] The probability of defect presence calculated based on different frequencies is multiplied to obtain the final probability of defect presence; the area with the highest probability of defect presence within the detection area is the location of the defect in the pipeline structure.

[0054] In a second aspect, embodiments of the present invention provide a computer-readable storage medium comprising a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to execute the referenceless identification method for the location of pipe structure defects based on multi-frequency spiral waveguides, as described in the first aspect or any possible implementation thereof.

[0055] Thirdly, embodiments of the present invention provide an electronic device, including: one or more processors; a memory; and one or more computer programs, wherein the one or more computer programs are stored in the memory, and the one or more computer programs include instructions that, when executed by the device, cause the device to perform the referenceless identification method for the location of pipe structure defects based on multi-frequency helical waveguides in the first aspect or any possible implementation of the first aspect.

[0056] The technical solution provided by this invention includes a method for constructing a pipeline structural defect detection system and grouping sensing paths; calculating a difference signal set based on the defect helical guided wave signal acquired by a piezoelectric sensing array according to the sensing path grouping; determining a defect factor based on the correlation coefficient between the difference signals to screen and obtain effective defect paths; and identifying the location of pipeline structural defects by fusing the probability of defect existence at different excitation frequencies according to the effective defect paths. This method achieves adaptive screening of defect paths and improves the accuracy and reliability of defect location. Attached Figure Description

[0057] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 A flowchart illustrating a non-reference-based method for identifying the location of pipe structural defects based on multi-frequency helical waveguides, as provided in an embodiment of the present invention.

[0059] Figure 2 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0062] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention are also intended to include the plural forms unless the context clearly indicates otherwise.

[0063] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0064] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0065] Figure 1 The flowchart of the pipeline structural defect location identification method based on multi-frequency helical waveguides provided in the embodiments of the present invention is as follows: Figure 1 As shown, the method includes:

[0066] Step 1: Construct a pipeline structural defect detection system and group the sensor paths.

[0067] In this embodiment of the invention, step 1 includes:

[0068] Step 11: Composition of the defect detection system;

[0069] A defect detection system for a pipeline structure is built using a host computer, an ultrasonic guided wave detection device, a piezoelectric sensor array, and a pipeline structure (including defects): (1) The host computer contains a software system that works with the ultrasonic guided wave detection device. The host computer is connected to the ultrasonic guided wave detection device, and data is transmitted bidirectionally between the two. The host computer is used to set the ultrasonic guided wave excitation signal parameters (such as frequency, number of peaks, amplitude, etc.) and the ultrasonic guided wave receiving signal parameters (such as the upper and lower limit frequencies of the bandpass filter and the storage path). (2) One end of the ultrasonic guided wave detection device is connected to the host computer, and the other end is connected to the piezoelectric sensor. The ultrasonic guided wave detection device is used to set the ultrasonic guided wave excitation signal based on the ultrasonic guided wave excitation signal set by the host computer. The parameters generate ultrasonic guided waves and transmit them to the excitation sensor in the piezoelectric sensing array; and are used to extract the guided wave signal received by the receiving sensor in the piezoelectric sensing array, and filter and store it according to the ultrasonic guided wave receiving signal parameters set by the host computer; (3) The piezoelectric sensing array is composed of 2N piezoelectric ceramic sensors; among them, N sensors are used as excitation sensors to convert the electrical signal emitted by the ultrasonic guided wave detection device into a stress signal, and then the stress signal will propagate outward in a circle on the surface of the pipe structure to form a spiral guided wave; the other N sensors are used as receiving sensors to convert the stress signal propagating along the surface of the pipe structure into an electrical signal;

[0070] Step 12: Arrangement of piezoelectric sensor array;

[0071] The arrangement and naming conventions for piezoelectric sensor arrays are as follows:

[0072] A sensor array consisting of N excitation sensors is called an excitation sensing array, denoted as A1, A2, ..., A N A sensor array consisting of N receiving sensors is called a receiving sensor array, denoted as R1, R2, ..., R3. N ;

[0073] Both the excitation sensor array plane and the receiving sensor array plane are perpendicular to the central axis of the pipe structure, and are uniformly pasted on the outer surface of the pipe structure with equal arc lengths; that is, if the outer radius of the pipe structure is r, then the adjacent excitation sensor A i' A i'+1 Or receive sensor R i' R i'+1 The arc length distance between the excitation sensor array and the receiving sensor array is 2πr / N, 1≤i'≤N-1; the axial distance between the excitation sensor array and the receiving sensor array is D, the value of which depends on the size of the defect identification area of ​​the pipeline structure under test. Excitation sensor A i With receiving sensor R i The straight-line distance between them is D, that is: the line connecting the excitation sensor and the receiving sensor with the same number i is parallel to the central axis of the pipe structure, 1≤i≤N;

[0074] Step 13: Grouping sensor paths;

[0075] The line segment connecting the excitation sensor and the receiving sensor in a clockwise direction along the surface of the pipe structure is called the sensing path. Therefore, for a sensing array consisting of N excitation sensors and N receiving sensors, there are a total of N... 2 A sensing path, denoted by the symbol P i→j Representative excitation sensor A i With receiving sensor R j The sensing paths between them are 1≤i≤N, 1≤j≤N;

[0076] Based on the length of the sensing path, all sensing paths are divided into N groups, and each group is represented by a P-type sensor. 1 PP 2 ... PP N This indicates that each group contains N sensing paths, which are: PP 1 ={P1 1 P2 1 , ..., P N-1 1 P N 1};PP 2 ={P1 2 P2 2 , ..., P N-1 2 P N 2};…;PP N ={P1 N P2 N , ..., P N-1 N P N N}; where path group PP j The i-th sensing path P in i j This refers to: Excitation sensor A i With receiving sensor R u The corresponding sensing path, where R u To R i The counterclockwise circumferential distance is In the formula, r is the outer radius of the pipe structure, and N is the number of excitation sensors or receiving sensors;

[0077] Based on the arrangement of the excitation sensor array and the receiving sensor array on the surface of the pipe structure, PP 1 The group contains the shortest sensing path distance, valued as D, which is the straight-line distance along the axial direction of the pipe structure between the excitation sensing array plane and the receiving sensing array plane; PP N The group contains the longest sensing path distance, with a value of In the formula, r is the outer radius of the pipe structure, and N is the number of excitation sensors or receiving sensors.

[0078] Step 2: Group the signals according to the sensing path, and calculate the difference signal set based on the defective spiral guided wave signals collected by the piezoelectric sensing array.

[0079] In this embodiment of the invention, step 2 includes:

[0080] Step 21: Group and name the defect ultrasonic guided wave signals W collected by the piezoelectric sensing array;

[0081] Let W represent the guided wave signal acquired by the sensor array under the condition of a pipe structure defect, i.e., the defect spiral guided wave signal; according to the definition of the sensor path group, W is expressed as W={W 1 W 2 ,…,W N}, where the guided wave signal corresponding to the k-th path group is W. k ={W1 k W2 k ,…,W N-1 k W N k}, where W i k Indicates the sensing path P i k The corresponding guided wave signal, i.e., when sensor A is excited. i When transmitting ultrasonic guided wave signals as a signal source, the defective helical guided wave signals received by the receiving sensor on the current path are 1≤k≤N;

[0082] If M represents the number of sampling points in the ultrasonic guided wave testing device, then the guided wave signal W i k The dimension is M×1, and the signal set W k The dimension is M×N;

[0083] Step 22: Calculate the difference signal S between the ultrasonic guided wave signals of defects within each path group. k ;

[0084] Based on the defective helical waveguide signal W acquired by the sensor array, the difference signal S={S 1 S 2 S N}, where the difference signal set S corresponding to the k-th path group k ={S1 k S2 k S N-1 k S N k}, 1≤k≤N, where Si k This indicates that within the k-th path group, excluding path P... i k External path P j k The corresponding defective guided wave signal W j k With path P i k The corresponding defective helical waveguide signal W i k The difference signal set, i.e., S i k Represented as S i k ={S i,1 k S i,2 k S i,N-1 k S i,N k}, where the j-th element S i,j k =W j k -W i k , 1≤i≤N, 1≤j≤N, and j≠i;

[0085] If M represents the number of sampling points in the ultrasonic guided wave testing device, then the difference signal S i,j k The dimension is M×1, and the difference signal set S i k The dimension is M×(N-1), and the difference signal set S k The dimension is M×(N-1)×N.

[0086] Step 3: Based on the correlation coefficient between the difference signals, determine the defect factors to screen and obtain effective defect paths.

[0087] In this embodiment of the invention, step 3 includes:

[0088] Step 31: Calculate the correlation coefficient between the difference signals;

[0089] Computation and Sensing Path P i k The corresponding difference signal set S i k The correlation coefficient between any two signals is expressed as follows:

[0090] ;

[0091] in, Indicates the difference signal and The correlation coefficient between them, where 1 ≤ m < n ≤ N, m ≠ i, n ≠ i, and m ≠ n; denotes the signal and The covariance between them, and respectively denote the standard deviations of the signals and ;

[0092] According to the grouping situation of the sensing paths and the definition of the correlation coefficient between the differential signals, based on the differential signal set S i k , calculate to obtain correlation coefficients, which are denoted as:

[0093] ;

[0094] Step 32: Define the defect factor of the sensing path;

[0095] For the i-th path P in the k-th path group i k , calculate its defect factor , and its expression is:

[0096] ;

[0097] where and respectively represent the mean and variance of the correlation coefficient vector ;

[0098] For the k-th path group, its corresponding defect factor set is d k = [d1 k , d2 k , … d N k ;

[0099] Step 33: Screen to obtain the effective defect path P valid ;

[0100] If there are defects in the area near the sensing path, the guided wave signal on this path will be affected, that is: the guided wave signal on this sensing path contains both the signal of the ultrasonic guided wave propagating normally along the surface of the pipeline structure and the guided wave signal reflected by the defect position. At this time, the guided wave signal on the sensing path affected by the defect is very different from the guided wave signal corresponding to the sensing path without defects in the nearby area, resulting in a large amplitude of the differential signal between the two.

[0101] If neither sensing path is affected by the defect, then due to the special characteristics of the pipe structure (closed and centrally symmetrical), the difference signal amplitude between the guided wave signals corresponding to these two paths is small (close to 0).

[0102] Since the N sensor paths within each path group are aligned and parallel in the two-dimensional plane, the number of sensor paths affected by defects within the same path group is limited. In other words, within the same path group, most sensor paths are unaffected by defects, with only a small number affected. Sensor paths significantly affected by defects are designated as valid defect paths, while those minimally affected or almost unaffected are designated as invalid defect paths.

[0103] The defect factor for a valid defect path is significantly larger than that for an invalid defect path. Therefore, different defect factor thresholds should be set for each path group. =10×min(d k ), where min(d k ) represents the defect factor set d k The minimum value;

[0104] Sensing paths with defect factors greater than a threshold are identified as valid defect paths P. valid ={{P valid 1}, {P valid 2},…,{P valid N}}, where P valid k This indicates that within the k-th path group, the defect factor is greater than the threshold. The set of sensing paths; if there is no path in the k-th path group that is greater than the threshold. If the defect factor is P, then P valid k It is an empty set.

[0105] Step 4: Based on the effective defect path, integrate the probability of defect existence under different excitation frequencies to identify the location of pipeline structural defects.

[0106] In this embodiment of the invention, step 4 includes:

[0107] Step 41: Calculate the probability of a defect existing at any position (x, y);

[0108] The defect detection area of ​​the pipeline structure is unfolded along the axial direction into a two-dimensional rectangular plane of size D×2πr, where D is the straight-line distance between the excitation sensor array plane and the receiving sensor array plane along the axial direction of the pipeline structure, and r is the outer radius of the pipeline structure. Then, the probability of the presence of a defect at any position (x, y) within the detection area is G.xy for:

[0109] ;

[0110] in, Let (x, y) represent the probability that a defect exists at (x, y) on a valid defect path p. That is, the probability of a defect at (x, y) is equal to the sum of the probabilities of a defect existing on all valid defect paths, where p ∈ P. valid ;

[0111] The expression is:

[0112] ;

[0113] in, The actual arrival time of the defect guided wave signal on the effective defect path p is represented by the difference signal set corresponding to the effective defect path p. The specific process is as follows: (1) Calculate the envelope signal of each signal in the difference signal set; (2) Add the envelope signals to obtain the total envelope signal; (3) The peak time of the total envelope signal is the actual arrival time of the defect guided wave signal on the effective defect path p. ; This indicates the theoretical arrival time of the guided wave signal received at the effective defect path p if (x,y) is the defect location. The specific calculation process is as follows: (1) Calculate the distance from the excitation sensor on the effective defect path p to (x,y) and then to the receiving sensor on the effective defect path p, denoted as (2) Combining the current guided wave signal excitation frequency with the propagation speed v of the guided wave in the pipe structure, we get ; This represents the time threshold, which is numerically equal to twice the period of the guided wave signal;

[0114] Step 42: Combine different excitation frequencies to calculate the location of defects in the pipeline structure;

[0115] To ensure the accuracy of defect location identification, q defect guided wave signals at different frequencies are collected, and the difference signal set, defect factor, effective defect path set, and defect existence probability at different frequencies are calculated sequentially.

[0116] The probability of defect presence calculated based on different frequencies is multiplied to obtain the final probability of defect presence; the area with the highest probability of defect presence within the detection area is the location of the defect in the pipeline structure.

[0117] Compared with the prior art, the present invention has the following advantages:

[0118] (1) No reference signal required: This method constructs a defect factor by analyzing the difference signal and its correlation coefficient between different sensing paths within the same path group, and realizes the adaptive screening of defect paths. It completely gets rid of the dependence on defect-free reference signals and is suitable for on-site detection scenarios where historical data is missing or reference signals cannot be obtained.

[0119] (2) High defect location accuracy: By introducing multi-frequency excitation signals and fusing defect existence probability maps at different frequencies, the accuracy and reliability of defect location are significantly improved, and misjudgment and missed judgment at a single frequency are effectively suppressed.

[0120] (3) Adaptive path selection mechanism: Based on the differential signal correlation coefficient, the defect factor and its dynamic threshold setting can automatically identify effective paths affected by defects, reduce human intervention, and improve the automation and objectivity of detection.

[0121] (4) Strong system robustness: The adoption of a multi-frequency data fusion strategy enhances the adaptability of the method to different defect types and different working conditions, and improves the stability and generalization ability of the system.

[0122] (5) High detection efficiency: Through sensor path grouping and parallel signal processing mechanism, efficient analysis of large-scale sensing paths is realized, which improves detection efficiency while ensuring accuracy and is suitable for rapid detection needs in industrial sites.

[0123] The technical solution provided by this invention includes a method for constructing a pipeline structural defect detection system and grouping sensing paths; calculating a difference signal set based on the defect helical guided wave signal acquired by a piezoelectric sensing array according to the sensing path grouping; determining a defect factor based on the correlation coefficient between the difference signals to screen and obtain effective defect paths; and identifying the location of pipeline structural defects by fusing the probability of defect existence under different excitation frequencies based on the effective defect paths. This method achieves adaptive screening of defect paths, improving the accuracy and reliability of defect location.

[0124] The various steps in the embodiments of the present invention can be performed by an electronic device. This electronic device includes, but is not limited to, tablet computers, portable PCs, and desktop computers.

[0125] This invention provides a computer-readable storage medium including a stored program, wherein, when the program is running, it controls the electronic device containing the computer-readable storage medium to execute the above-described embodiment of the pipeline structure defect location identification method based on multi-frequency spiral waveguide.

[0126] Figure 2 A schematic diagram of an electronic device provided in an embodiment of the present invention, such as... Figure 2As shown, the electronic device 21 includes a processor 211, a memory 212, and a computer program 213 stored in the memory 212 and executable on the processor 211. When the computer program 213 is executed by the processor 211, it implements the referenceless identification method for the location of pipe structure defects based on multi-frequency spiral waveguides in the embodiment. To avoid repetition, it will not be described in detail here.

[0127] Electronic device 21 includes, but is not limited to, processor 211 and memory 212. Those skilled in the art will understand that... Figure 2 This is merely an example of electronic device 21 and does not constitute a limitation on electronic device 21. It may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device may also include input / output devices, network access devices, buses, etc.

[0128] The processor 211 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0129] The memory 212 can be an internal storage unit of the electronic device 21, such as a hard disk or RAM of the electronic device 21. The memory 212 can also be an external storage device of the electronic device 21, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or FlashCard equipped on the electronic device 21. Furthermore, the memory 212 can include both internal and external storage units of the electronic device 21. The memory 212 is used to store computer programs and other programs and data required by network devices. The memory 212 can also be used to temporarily store data that has been output or will be output.

[0130] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for identifying the location of defects in pipe structures without a reference based on multi-frequency helical guided waves, characterized in that, The method includes: Step 1: Construct a pipeline structural defect detection system and group the sensor paths; Step 2: Group the signals according to the sensing path, and calculate the difference signal set based on the defective spiral guided wave signals collected by the piezoelectric sensing array; Step 3: Based on the correlation coefficient between the difference signals, determine the defect factors to screen and obtain effective defect paths; Step 4: Based on the effective defect path, fuse the probability of defect existence under different excitation frequencies to identify the location of defects in the pipeline structure; Step 3 includes: Step 31: Calculate the correlation coefficient between the difference signals; Computation and Sensing Path P i k The corresponding difference signal set S i k The correlation coefficient between any two signals is expressed as follows: ； Among them, represents the correlation coefficient between the difference signals and where 1 ≤ m < n ≤ N, and m ≠ i, n ≠ i, m ≠ n; represents the covariance between the signals and ; and respectively represent the standard deviations of the signals and ; Based on the sensing path grouping and the definition of the correlation coefficient between the difference signals, based on the difference signal set S i k Calculations yielded The correlation coefficients are denoted as: ； Step 32: Define the defect factor of the sensing path; For the i-th path P within the k-th path group i k Calculate its defect factor Its expression is: ； in, and These represent the correlation coefficient vectors respectively. The mean and variance; For the k-th path group, its corresponding set of defect factors is d. k =[d1 k d2 k , ...d N k ]; Step 33: Filter and obtain valid defect paths P valid ; Different defect factor thresholds are set for each path group. =10×min(d k ), where min(d k ) represents the defect factor set d k The minimum value; Sensing paths with defect factors greater than a threshold are identified as valid defect paths P. valid ={{P valid 1 }, {P valid 2 },…,{P valid N }}, where P valid k This indicates that within the k-th path group, the defect factor is greater than the threshold. The set of sensing paths; if there is no path in the k-th path group that is greater than the threshold. If the defect factor is P, then valid k It is an empty set.

2. The method according to claim 1, characterized in that, Step 1 includes: Step 11: Composition of the defect detection system; A defect detection system for a pipeline structure is built using a host computer, an ultrasonic guided wave detection device, a piezoelectric sensor array, and a pipeline structure: (1) The host computer is connected to the ultrasonic guided wave detection device, and data is transmitted bidirectionally between the two. The host computer is used to set the ultrasonic guided wave excitation signal parameters and ultrasonic guided wave receiving signal parameters. (2) One end of the ultrasonic guided wave detection device is connected to the host computer, and the other end is connected to the piezoelectric sensor. The ultrasonic guided wave detection device is used to generate ultrasonic guided waves based on the ultrasonic guided wave excitation signal parameters set by the host computer, and transmit them to the excitation sensor in the piezoelectric sensor array. It is also used to extract the guided wave signal received by the receiving sensor in the piezoelectric sensor array, and filter and store it according to the ultrasonic guided wave receiving signal parameters set by the host computer. (3) The piezoelectric sensor array consists of 2N piezoelectric ceramic sensors. Among them, N sensors are used as excitation sensors to convert the electrical signal emitted by the ultrasonic guided wave detection device into a stress signal. Then, the stress signal will propagate outward in a circular pattern on the surface of the pipeline structure to form a spiral guided wave. The other N sensors are used as receiving sensors to convert the stress signal propagating along the surface of the pipeline structure into an electrical signal. Step 12: Arrangement of piezoelectric sensor array; The arrangement and naming conventions for piezoelectric sensor arrays are as follows: A sensor array consisting of N excitation sensors is called an excitation sensing array, denoted as A1, A2, ..., A N A sensor array consisting of N receiving sensors is called a receiving sensor array, denoted as R1, R2, ..., R3. N ; Both the excitation sensor array plane and the receiving sensor array plane are perpendicular to the central axis of the pipe structure, and are uniformly pasted on the outer surface of the pipe structure with equal arc lengths; that is, if the outer radius of the pipe structure is r, then the adjacent excitation sensor A i' A i'+1 Or receive sensor R i' R i'+1 The arc length between them is 2πr / N, 1≤i'≤N-1; excitation sensor A i With receiving sensor R i The straight-line distance between them is D, that is: the line connecting the excitation sensor and the receiving sensor with the same number i is parallel to the central axis of the pipe structure, 1≤i≤N; Step 13: Grouping sensor paths; The line segment connecting the excitation sensor and the receiving sensor in a clockwise direction along the surface of the pipe structure is called the sensing path. Therefore, for a sensing array consisting of N excitation sensors and N receiving sensors, there are a total of N... 2 A sensing path, denoted by the symbol P i→j Representative excitation sensor A i With receiving sensor R j The sensing paths between them are 1≤i≤N, 1≤j≤N; Based on the length of the sensing path, all sensing paths are divided into N groups, and each group is represented by a P-type sensor. 1 PP 2 ... PP N This indicates that each group contains N sensing paths, which are: PP 1 ={P1 1 P2 1 , ..., P N-1 1 P N 1 };PP 2 ={P1 2 P2 2 , ..., P N-1 2 P N 2 };…;PP N ={P1 N P2 N , ..., P N-1 N P N N }; where path group PP j The i-th sensing path P in i j This refers to: Excitation sensor A i With receiving sensor R u The corresponding sensing path, where R u To R i The counterclockwise circumferential distance is In the formula, r is the outer radius of the pipe structure, and N is the number of excitation sensors or receiving sensors; Based on the arrangement of the excitation sensor array and the receiving sensor array on the surface of the pipe structure, PP 1 The group contains the shortest sensing path distance, valued as D, which is the straight-line distance along the axial direction of the pipe structure between the excitation sensing array plane and the receiving sensing array plane; PP N The group contains the longest sensing path distance, with a value of In the formula, r is the outer radius of the pipe structure, and N is the number of excitation sensors or receiving sensors.

3. The method according to claim 2, characterized in that, Step 2 includes: Step 21: Group and name the defect ultrasonic guided wave signals W collected by the piezoelectric sensing array; Let W represent the guided wave signal acquired by the sensor array under the condition of a pipe structure defect, i.e., the defect spiral guided wave signal; according to the definition of the sensor path group, W is expressed as W={W 1 W 2 ,…,W N }, where the guided wave signal corresponding to the k-th path group is W. k ={W1 k W2 k ,…,W N-1 k W N k }, where W i k Indicates the sensing path P i k The corresponding guided wave signal, i.e., when sensor A is excited. i When transmitting ultrasonic guided wave signals as a signal source, the defective helical guided wave signals received by the receiving sensor on the current path are 1≤k≤N; If M represents the number of sampling points in the ultrasonic guided wave testing device, then the guided wave signal W i k The dimension is M×1, and the signal set W k The dimension is M×N; Step 22: Calculate the difference signal S between the ultrasonic guided wave signals of defects within each path group. k ; Based on the defective helical waveguide signal W acquired by the sensor array, the difference signal S={S 1 S 2 S N }, where the difference signal set S corresponding to the k-th path group k ={S1 k S2 k S N-1 k S N k }, 1≤k≤N, where S i k This indicates that within the k-th path group, excluding path P... i k External path P j k The corresponding defective guided wave signal W j k With path P i k The corresponding defective helical waveguide signal W i k The difference signal set, i.e., S i k Represented as S i k ={S i,1 k S i,2 k S i,N-1 k S i,N k }, where the j-th element S i,j k =W j k -W i k , 1≤i≤N, 1≤j≤N, and j≠i; If M represents the number of sampling points in the ultrasonic guided wave testing device, then the difference signal S i,j k The dimension is M×1, and the difference signal set S i k The dimension is M×(N-1), and the difference signal set S k The dimension is M×(N-1)×N.

4. The method according to claim 1, characterized in that, Step 4 includes: Step 41: Calculate the probability of a defect existing at any position (x, y); The defect detection area of ​​the pipeline structure is unfolded along the axial direction into a two-dimensional rectangular plane of size D×2πr, where D is the straight-line distance between the excitation sensor array plane and the receiving sensor array plane along the axial direction of the pipeline structure, and r is the outer radius of the pipeline structure. Then, the probability of the presence of a defect at any position (x, y) within the detection area is G. xy for: ； in, Let (x, y) represent the probability that a defect exists at (x, y) on a valid defect path p. That is, the probability of a defect existing at (x, y) is equal to the sum of the probabilities of a defect existing on all valid defect paths, where p ∈ P. valid ; The expression is: ； in, This indicates the actual arrival time of the defect guided wave signal on the effective defect path p; This represents the theoretical arrival time of the guided wave signal received by the effective defect path p at the defect location if (x,y) is the defect location. This represents the time threshold, which is numerically equal to twice the period of the guided wave signal; Step 42: Combine different excitation frequencies to calculate the location of defects in the pipeline structure; Collect q defect guided wave signals at different frequencies, and calculate the difference signal set, defect factor, effective defect path set, and defect existence probability at different frequencies in sequence; The probability of defect presence calculated based on different frequencies is multiplied to obtain the final probability of defect presence; the area with the highest probability of defect presence within the detection area is the location of the defect in the pipeline structure.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the reference-free identification method for pipeline structural defect location based on multi-frequency helical waveguides as described in any one of claims 1 to 4.

6. An electronic device, characterized in that, include: One or more processors; Memory; And one or more computer programs, wherein the one or more computer programs are stored in the memory, and the one or more computer programs include instructions that, when executed by the device, cause the device to perform the referenceless identification method for pipeline structure defect location based on multi-frequency helical waveguides as described in any one of claims 1 to 4.

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