Method and system for representing all-round corrosion state of cross section of sling based on spontaneous magnetic flux leakage

Abstract

The invention discloses a method and a system for characterizing a full-cycle corrosion state of a cross section of a pull sling based on spontaneous magnetic flux leakage, belongs to the field of bridge pull sling structure corrosion damage diagnosis, and establishes a precise characterization method for the full-cycle corrosion state of the pull sling based on a spontaneous magnetic flux leakage technology. By monitoring the change of the magnetic induction intensity component Bx along the length of the sling and overlying and analyzing the Bx distribution under different paths, the preliminary identification of the corrosion position is realized. Furthermore, the corrosion number and the corrosion position are accurately quantified by utilizing the correlation between the Bx peak value and the circumferential position of the Bx peak value. Meanwhile, the circumferential corrosion rate and the central angle are obtained through integral and relational graph analysis, and then the corrosion depth is evaluated. According to the method, a scientific and comprehensive evaluation means is provided for the all-round corrosion state of the in-service pull sling, and the accuracy and efficiency of structure safety monitoring can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion damage diagnosis of bridge cable structures, and more particularly to a method and system for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic leakage. Background Art

[0002] The stay cable is the main load-bearing structure in the cable bridge. Under the combined effects of complex environment and long-term stress, its sheath is very easy to be damaged, which increases the probability of damage to the internal steel strands or wire bundles. When the cable body is damaged, the ultimate bearing capacity of the bridge will be reduced. Once the damage accumulates to the limit, it will destroy the use function of the bridge. The damage of the cable is mainly divided into the full circumference of the long axis and short axis of the cable. Among them, the full circumference damage of the stay cable is greatly related to the judgment of the cable state. Therefore, full circumference non-destructive testing of the cable has great practical value and scientific significance.

[0003] Spontaneous magnetic flux leakage detection is a non-destructive testing method proposed by Dubov based on the magnetic memory characteristics of ferromagnetic materials. After years of exploration and research, this technology has been widely used in mechanical engineering, aerospace, civil engineering, chemical engineering and petroleum. In civil engineering, this method is often used for slings with ferromagnetic characteristics to detect their internal damage. Due to environmental reasons, the damage of slings often exists in the form of full-circle multi-point corrosion damage, and the existing quantification methods are difficult to quantify the number, location, depth, angle range and corrosion rate of full-circle corrosion, and lack corresponding quantification formulas.

[0004] Therefore, how to provide a method and system for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic leakage is an issue that needs to be urgently addressed by those skilled in the art. Summary of the invention

[0005] In view of this, the present invention provides a method and system for characterizing the all-round corrosion state of the cross-section of a sling cable based on spontaneous magnetic leakage, which can quantify the number, position, depth, angle range and corrosion rate of all-round corrosion of the sling cable.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] On the one hand, the present invention provides a method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic leakage, comprising the following steps:

[0008] S1. Use the magnetic array sensor to obtain the detection value B of the magnetic induction intensity in the x direction of the sling x , and draw xB x Distribution line chart;

[0009] S2, along the x direction, all xB under the detection pathx The polylines are superimposed to obtain xB x-S Overlay graph;

[0010] S3, according to the xB x-S The overlay image obtains the detection value B after overlay x-S Detection value B of the cross section where the maximum peak is located x-max , the cross-sectional detection value B where the maximum peak is located x-max The maximum peak value of the cross section detection value B x-max The corresponding circumferential position θ is plotted as θ-B x-max Line chart;

[0011] S4, according to the θ-B x-max The number of single peak convexities n of the broken line is obtained from the broken line graph, and the number of preliminary circumferential concentrated corrosion c' is determined; x-max The slope B of two adjacent points in the line graph x-max＇ Perform normalization processing, and determine the precise circumferential concentrated corrosion number c according to the relationship between the normalization result and the circumferential position θ;

[0012] S5. Classify and quantify the circumferential concentrated corrosion center θ according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c. c ;

[0013] S6, for the θ-B x-max The line graph is integrated within 0°≤θ≤360° to obtain the full-circle signal integral value B of the sling cross section. x-maxS Value, according to B x-maxS -α relationship diagram, the circumferential corrosion rate α is obtained;

[0014] S7, calculate the full-circle signal integral value B of the cross section of the sling x-maxS Obtaining a processed value s, determining a processed value l of the circumferential corrosion center angle L according to the sl relationship diagram, and then obtaining the circumferential corrosion center angle L according to an inverse formula of the processed value l of the circumferential corrosion center angle L;

[0015] S8. Determine the circumferential corrosion depth h by combining the circumferential corrosion rate α and the circumferential corrosion center angle L.

[0016] Preferably, S3 includes:

[0017] The maximum peak cross-sectional detection value B x-max The maximum peak value of the cross section detection value B x-max The corresponding circumferential position θ is plotted as θ-B after two cycles. x-max Line chart.

[0018] Preferably, S4 includes:

[0019] S401, according to Figure θ-B x-max The distribution characteristics of the broken line graph shape are used to obtain the number n of single-peak protrusions of the broken line, and the preliminary circumferential concentrated corrosion number c' is calculated based on the number of single-peak protrusions:

[0020]

[0021] Where n is θ-B x-max The number of unimodal bulges in the line chart;

[0022] S402, for θ-B x-max The slope B of two adjacent points in the line graph x-max＇ Normalization is performed to obtain a normalized value e, and an e-θ relationship diagram is drawn according to the relationship between the normalized value e and the circumferential position θ. The relationship between θ-B is calculated according to the e-θ relationship diagram. x-max The extreme value spacing corresponding to the single peak bulge in the line graph is used to calculate the precise number of circumferential concentrated corrosion c:

[0023]

[0024] Among them, L n is the extreme value spacing of the nth single peak protrusion, L n-mode is the mode value of the distance between the extreme values ​​of a single protrusion.

[0025] Preferably, S5 includes:

[0026] S501, determining a calculation method for the axial concentrated corrosion center according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c;

[0027] S502, when c = c', then through θ-B x-max The peak of the line graph is the corrosion center θ max Circumferential corrosion centerθ c Calculation of: θ c =θ max

[0028] S503, when c≠c', by x-max The line graph is fitted with the Lorentz curve, and the peak value of the Lorentz curve is taken as θ L is the circumferential corrosion center θ c The calculation is used to calculate the peak of the Lorentz curve θ L The expression is:

[0029]

[0030] Among them, w and A are the fitting parameters of the circumferential corrosion degree and corrosion angle range.

[0031] Preferably, for θ-B x-max The calculation formula for the integral of the line chart is:

[0032]

[0033] The calculation formula of circumferential corrosion rate α is:

[0034] α=0.000083·B x-maxS -2.48

[0035] Among them, B x-maxS It is the integral value of the full-circle signal of the cross section of the sling.

[0036] Preferably, the full-circumference signal integral value B of the cross section of the sling is x-maxS The calculation formula of the processing value s is:

[0037]

[0038] Preferably, the calculation formula of the circumferential corrosion center angle L is:

[0039] L=d·(1+l)=d·(1+4.2s)(0<s<1.90)

[0040] Where d is the known starting central angle of circumferential corrosion.

[0041] Preferably, the calculation formula for the circumferential corrosion depth h is:

[0042]

[0043] Where r is the radius of the specimen.

[0044] On the other hand, the present invention provides a system for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic leakage, which is used to implement the above-mentioned method for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic leakage, comprising:

[0045] Magnetic array sensor, used to obtain the detection value B of the magnetic induction intensity in the x direction of the sling x ;

[0046] The distribution map generation module is used to generate the distribution map according to the x direction of the pull rope and the corresponding detection value B x Generate xB x Distribution line chart;

[0047] The superposition module is used to add all xB under the detection path along the x direction. x The polylines are superimposed to obtain xB x-S Overlay graph;

[0048] θ-B x-max A line chart generation module is used to generate a line chart according to the xB x-S The overlay image obtains the detection value B after overlay x-S Detection value B of the cross section where the maximum peak is located x-max , the cross-sectional detection value B where the maximum peak is located x-max The maximum peak value of the cross section detection value B x-max The corresponding circumferential position θ is plotted as θ-B x-max Line chart;

[0049] The module for determining the number of circumferential concentrated corrosion is used to determine the number of circumferential concentrated corrosion according to the graph θ-B x-max The number of single peak convexities n of the broken line is obtained from the broken line graph, and the number of preliminary circumferential concentrated corrosion c' is determined; x-max The slope B of two adjacent points in the line graph x-max＇ Perform normalization processing, and determine the precise circumferential concentrated corrosion number c according to the relationship between the normalization result and the circumferential position θ;

[0050] A circumferential concentrated corrosion center determination module is used to classify and quantify the circumferential concentrated corrosion center θ according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c c ;

[0051] Circumferential corrosion rate calculation module, used for the θ-B x-max The line graph is integrated within 0°≤θ≤360° to obtain the full-circle signal integral value B of the sling cross section. x-maxS Value, according to B x-maxS -α relationship diagram, the circumferential corrosion rate α is obtained;

[0052] The module for calculating the central angle of circumferential corrosion is used to calculate the integral value B of the full-circumference signal of the cross section of the sling. x-maxS Obtaining a processed value s, determining a processed value l of the circumferential corrosion center angle L according to the sl relationship diagram, and then obtaining the circumferential corrosion center angle L according to an inverse formula of the processed value l of the circumferential corrosion center angle L;

[0053] The circumferential corrosion depth calculation module is used to determine the circumferential corrosion depth h by combining the circumferential corrosion rate α and the circumferential corrosion center angle L.

[0054] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method and system for characterizing the full-circle corrosion state of the cross section of the cable pull rope based on spontaneous magnetic leakage. Relying on the spontaneous magnetic leakage detection technology, a comprehensive characterization system for the full-circle corrosion state of the cross section of the cable pull rope is constructed. Specifically, by deeply analyzing the θ-B x-maxBased on the distribution characteristics of the line graph, a calculation formula for quantifying the number and location of corrosion points in the sling was proposed. x-maxS Through fine processing and analysis, an accurate determination method for the circumferential center angle and corrosion depth of the corrosion area is also realized. These characterization formulas not only significantly improve the accuracy and efficiency of the full-circumference corrosion status assessment of in-service slings, but also provide strong technical support and scientific basis for a more comprehensive and in-depth understanding and response to the corrosion problem of slings. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0056] Figure 1 It is a flow chart of a method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic leakage disclosed by the present invention;

[0057] Figure 2 It is a schematic diagram of various parameters of the full-circle corrosion state of the sling disclosed in the present invention;

[0058] Figure 3 The pull rope signal B disclosed in the present invention x-max＇ Correlation model between normalized value e and circumferential position θ (e-θ diagram);

[0059] Figure 4 The circumferential position θ and the magnetic flux leakage signal value B disclosed in the present invention are x-max Correlation model (Lorentz fitting curve graph);

[0060] Figure 5 is the integrated area B disclosed in the present invention x-maxS Correlation model with corrosion rate α (B x-maxS-α picture);

[0061] Figure 6 The present invention discloses a correlation model between the signal integral processing value s and the circumferential corrosion center angle processing value l (sl diagram). DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] The embodiment of the present invention discloses a method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic leakage. Figure 1-2 As shown, the following steps are included:

[0064] S1. Use the magnetic array sensor to obtain the detection value B of the magnetic induction intensity in the x direction of the sling x , and draw xB x Distribution line chart.

[0065] Specifically, the distance between the magnetic array sensor and the surface of the cable is always kept constant, and the x-direction component B of the magnetic induction intensity of the cable is recorded along the length direction (x-direction) of the cable. x , and draw xB x Distribution line.

[0066] When recording, in addition to recording the magnetic induction intensity B in the x direction of the sling, x , and also record its position and distance information, where the position information is the length position of the straight line where the sling is located as the horizontal axis, and the distance information is the magnetic induction intensity B collected x The distance between the magnetic array sensor and the surface of the sling when

[0067] S2, along the x direction, all xB under the detection path x The polylines are superimposed to obtain xB x-S Overlay chart.

[0068] S3, according to xB x-S The overlay image obtains the detection value B after overlay x-S Detection value B of the cross section where the maximum peak is located x-max , the cross-section detection value B where the maximum peak is located x-max The cross-sectional detection value B of the maximum peak x-max The corresponding circumferential position θ is plotted as θ-B x-max Line chart.

[0069] S4, according to θ-B x-max The number of single peak convexities n of the broken line is obtained from the broken line graph, and the number of preliminary circumferential concentrated corrosion c' is determined; x-max The slope B of two adjacent points in the line graph x-max＇ Normalization processing is performed, and the precise circumferential concentrated corrosion number c is determined based on the relationship between the normalization result and the circumferential position θ.

[0070] S5. Classify and quantify the circumferential concentrated corrosion center θ according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c c .

[0071] S6, for θ-Bx-max The line graph is integrated within 0°≤θ≤360° to obtain the full-circle signal integral value B of the sling cross section. x-maxS Value, according to B x-maxS -α relationship diagram, the circumferential corrosion rate α, B x-maxS-α The relationship diagram is drawn by pulling the sling corrosion situation, such as Figure 5 shown.

[0072] S7. Calculate the full-circle signal integral value B of the cross section of the sling x-maxS The processing value s is obtained, and the processing value l of the circumferential corrosion center angle L is determined according to the sl relationship diagram, and then the circumferential corrosion center angle L is obtained according to the inverse formula of the processing value l of the circumferential corrosion center angle L. Among them, the sl relationship diagram is drawn according to the corrosion situation of the sling.

[0073] Passed 2-18-1# specimen B x-maxS Value, B for all specimens x-maxS The value is processed to obtain s, and the circumferential corrosion center angle processing value l is determined by combining the "sl relationship diagram". The sl relationship diagram is as follows Figure 6 shown.

[0074] S8. Determine the circumferential corrosion depth h by combining the circumferential corrosion rate α and the circumferential corrosion center angle L.

[0075] Furthermore, S3 includes:

[0076] Maximum peak cross-section detection value B x-max The cross-sectional detection value B of the maximum peak x-max The corresponding circumferential position θ is plotted as θ-B after two cycles. x-max Line chart.

[0077] Furthermore, S4 includes:

[0078] S401, according to Figure θ-B x-max The distribution characteristics of the broken line shape are used to obtain the number of single-peak protrusions n of the broken line. The preliminary circumferential concentrated corrosion number c' is calculated based on the number of single-peak protrusions:

[0079]

[0080] Where n is the graph θ-B x-max The number of unimodal bulges in the line chart;

[0081] S402, for θ-B x-max The slope B of two adjacent points in the line graph x-max＇ Normalize to get the normalized value e, and draw an e-θ relationship diagram based on the relationship between the normalized value e and the circumferential position θ. The e-θ relationship diagram is as follows: Figure 3As shown, according to the e-θ relationship diagram, the relationship between θ and B is calculated. x-max The extreme value spacing corresponding to the single peak bulge in the line graph is used to calculate the precise number of circumferential concentrated corrosion c:

[0082]

[0083] Among them, L n is the extreme value spacing of the nth single peak protrusion, L n-mode is the mode value of the distance between the extreme values ​​of a single protrusion, which is 60.

[0084] Specifically, S5 includes:

[0085] S501, determining a calculation method for the axial concentrated corrosion center based on the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c;

[0086] S502, when c = c', through θ-B x-max The peak of the line graph is the corrosion center θ max Circumferential corrosion centerθ c Calculation of: θ c =θ max

[0087] S503, when c≠c', by x-max The line graph is used to fit the Lorentz curve. The Lorentz fitting curve is shown in the figure below. Figure 4 As shown, take the peak value of the Lorentz curve as θ L is the circumferential corrosion center θ c Calculation is used to calculate the peak of the Lorentz curve θ L The expression is:

[0088]

[0089] Among them, w and A are the fitting parameters of the circumferential corrosion degree and corrosion angle range.

[0090] Therefore, the circumferential corrosion center θ in S501 c The segment calculation formula is:

[0091]

[0092] In the formula, θ max θ-B x-max In the line chart, B x-max The peak value corresponds to θ, θ L The horizontal axis corresponds to the peak value of the Lorentz fitting curve.

[0093] Furthermore, for θ-B x-maxThe calculation formula for the integral of the line chart is:

[0094]

[0095] The calculation formula of circumferential corrosion rate α is:

[0096] α=0.000083·B x-maxS -2.48

[0097] Among them, B x-maxS It is the integral value of the full-circle signal of the cross section of the sling.

[0098] Furthermore, the full-circle signal integral value B of the sling cross section x-maxS The calculation formula of the processing value s is:

[0099]

[0100] Furthermore, the calculation formula of the circumferential corrosion center angle L is:

[0101] L=d·(1+l)=d·(1+4.2s)(0<s<1.90)

[0102] Where s is B x-maxS The processing value of s is limited by L and its value range is 0~1.90; d is the known starting circumferential corrosion center angle, which is 40, corresponding to the circumferential corrosion center angle of the specimen when N=2.

[0103] Furthermore, the calculation formula for the circumferential corrosion depth h is:

[0104]

[0105] Where r is the radius of the specimen, which is 7 mm.

[0106] On the other hand, the present invention provides a system for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic leakage, which is used to implement the above-mentioned method for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic leakage, comprising:

[0107] Magnetic array sensor, used to obtain the detection value B of the magnetic induction intensity in the x direction of the sling x ;

[0108] The distribution map generation module is used to generate the distribution map according to the x direction of the pull rope and the corresponding detection value B x Generate xB x Distribution line chart;

[0109] The superposition module is used to add xB along all the detection paths in the x direction. x The polylines are superimposed to obtain xB x-S Overlay graph;

[0110] θ-B x-max Line chart generation module, used to generate x-S The overlay image obtains the detection value B after overlay x-S Detection value B of the cross section where the maximum peak is located x-max , the cross-section detection value B where the maximum peak is located x-max The cross-sectional detection value B of the maximum peak x-max The corresponding circumferential position θ is plotted as θ-B x-max Line chart;

[0111] The module for determining the number of circumferential concentrated corrosion is used to determine the number of circumferential concentrated corrosion according to the graph θ-B x-max The number of single peak convexities n of the broken line is obtained from the broken line graph, and the number of preliminary circumferential concentrated corrosion c' is determined; for θ-B x-max The slope B of two adjacent points in the line graph x-max＇ Perform normalization processing, and determine the precise circumferential concentrated corrosion number c according to the relationship between the normalization result and the circumferential position θ;

[0112] The module for determining the circumferential concentrated corrosion center is used to classify and quantify the circumferential concentrated corrosion center θ according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c c ;

[0113] Circumferential corrosion rate calculation module, used for θ-B x-max The line graph is integrated within 0°≤θ≤360° to obtain the full-circle signal integral value B of the sling cross section. x-maxS Value, B plotted according to the corrosion of the cable x-maxS -α relationship diagram, the circumferential corrosion rate α is obtained;

[0114] Circumferential corrosion center angle calculation module, used to calculate the full-circle signal integral value B of the cross section of the sling x-maxS The treatment value s is obtained, and the treatment value l of the circumferential corrosion center angle L is determined according to the sl relationship diagram drawn according to the corrosion condition of the sling cable, and then the circumferential corrosion center angle L is obtained according to the inverse formula of the treatment value l of the circumferential corrosion center angle L;

[0115] The circumferential corrosion depth calculation module is used to determine the circumferential corrosion depth h by combining the circumferential corrosion rate α and the circumferential corrosion center angle L.

[0116] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0117] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic leakage, characterized in that: The following steps are involved: S1. Use the magnetic array sensor to obtain the detection value B of the magnetic induction intensity in the x direction of the sling x , and draw xB x Distribution line chart; S2, along the x direction, scan the xB under each sensor path x The polylines are superimposed to obtain xB x-S Overlay graph; S3, according to the xB x-S The overlay image obtains the detection value B after overlay x-S Maximum peak cross-section detection value B x-max , the cross-sectional detection value B where the maximum peak is located x-max The maximum peak value of the cross section detection value B x-max The corresponding circumferential position θ is plotted as θ-B x-max Line chart; S4, according to the θ-B x-max The number of single peak convexities n of the broken line is obtained from the broken line graph, and the number of preliminary circumferential concentrated corrosion c' is determined; x-max The slope B of two adjacent points in the line graph x-max 'Perform normalization processing, and determine the precise circumferential concentrated corrosion number c according to the relationship between the normalization result and the circumferential position θ; S5. Classify and quantify the circumferential concentrated corrosion center θ according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c. c ; S6, for the θ-B x-max The line graph is integrated within 0°≤θ≤360° to obtain the full-circle signal integral value B of the sling cross section. x-maxS Value, according to B x-maxS -α relationship diagram, the circumferential corrosion rate α is obtained; S7, calculate the full-circle signal integral value B of the cross section of the sling x-maxS Obtaining a processed value s, determining a processed value l of the circumferential corrosion center angle L according to the sl relationship diagram, and then obtaining the circumferential corrosion center angle L according to an inverse formula of the processed value l of the circumferential corrosion center angle L; S8. Determine the circumferential corrosion depth h by combining the circumferential corrosion rate α and the circumferential corrosion center angle L.

2. The method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic flux leakage according to claim 1, characterized in that S3 include: The maximum peak cross-sectional detection value B x-max The maximum peak value of the cross section detection value B x-max The corresponding circumferential position θ is plotted as θ-B after two cycles. x-max Line chart.

3. The method for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic flux leakage according to claim 1, characterized in that S4 include: S401, according to θ-B x-max The distribution characteristics of the broken line graph shape are used to obtain the number n of single-peak protrusions of the broken line, and the preliminary circumferential concentrated corrosion number c' is calculated based on the number of single-peak protrusions: Where n is θ-B x-max The number of unimodal bulges in the line chart; S402, for θ-B x-max The slope B of two adjacent points in the line graph x-max＇ Normalization is performed to obtain a normalized value e, and an e-θ relationship diagram is drawn according to the relationship between the normalized value e and the circumferential position θ. The relationship between θ-B is calculated according to the e-θ relationship diagram. x-max The extreme value spacing corresponding to the single peak bulge in the line graph is used to calculate the precise number of circumferential concentrated corrosion c: Among them, L n is the extreme value spacing of the nth single peak protrusion, L n-mode is the mode value of the distance between the extreme values ​​of a single protrusion.

4. The method for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic flux leakage according to claim 1, characterized in that S5 include: S501, determining a calculation method for the axial concentrated corrosion center according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c; S502, when c = c', through θ-B x-max The peak of the line graph is the corrosion center θ max Circumferential corrosion centerθ c Calculation of: θ c =θ max S503, when c≠c', by x-max The line graph is fitted with the Lorentz curve, and the peak value of the Lorentz curve is taken as θ L is the circumferential corrosion center θ c The calculation is used to calculate the peak of the Lorentz curve θ L The expression is: Among them, w and A are the fitting parameters of the circumferential corrosion degree and corrosion angle range.

5. The method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic flux leakage according to claim 1 is characterized in that: For θ-B x-max The calculation formula for the integral of the line chart is: The calculation formula of circumferential corrosion rate α is: α＝0.000083·B x-maxS -2.48 Among them, B x-maxS It is the integral value of the full-circle signal of the cross section of the sling.

6. The method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic flux leakage according to claim 1 is characterized in that: The full-circle signal integral value B of the cross section of the sling x-maxS The calculation formula of the processing value s is:

7. The method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic flux leakage according to claim 1 is characterized in that: The calculation formula of the circumferential corrosion center angle L is: L=d·(1+l)=d·(1+4.2s)(0<s<1.90) Where d is the known starting central angle of circumferential corrosion.

8. The method for characterizing the full-circumference corrosion state of a sling cross section based on spontaneous magnetic flux leakage according to claim 1 is characterized in that: The calculation formula of the circumferential corrosion depth h is: Where r is the radius of the specimen.

9. A system for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic flux leakage, used to implement a method for characterizing the full-circumference corrosion state of a cable cross section based on spontaneous magnetic flux leakage as described in any one of claims 1 to 8, characterized in that: include: Magnetic array sensor, used to obtain the detection value B of the magnetic induction intensity in the x direction of the sling x ; The distribution map generation module is used to generate the distribution map according to the x direction of the pull rope and the corresponding detection value B x Generate xB x Distribution line chart; The superposition module is used to add xB along all the detection paths in the x direction. x The polylines are superimposed to obtain xB x-S Overlay graph; θ-B x-max A line chart generation module is used to generate a line chart according to the xB x-S The overlay image obtains the detection value B after overlay x-S Detection value B of the cross section where the maximum peak is located x-max , the cross-sectional detection value B where the maximum peak is located x-max The maximum peak value of the cross section detection value B x-max The corresponding circumferential position θ is plotted as θ-B x-max Line chart; The module for determining the number of circumferential concentrated corrosion is used to determine the number of circumferential concentrated corrosion according to the θ-B x-max The number of single peak convexities n of the broken line is obtained from the broken line graph, and the number of preliminary circumferential concentrated corrosion c' is determined; x-max The slope B of two adjacent points in the line graph x-max＇ Perform normalization processing, and determine the precise circumferential concentrated corrosion number c according to the relationship between the normalization result and the circumferential position θ; A circumferential concentrated corrosion center determination module is used to classify and quantify the circumferential concentrated corrosion center θ according to the relationship between the preliminary circumferential concentrated corrosion number c' and the precise circumferential concentrated corrosion number c c ; Circumferential corrosion rate calculation module, used for the θ-B x-max The line graph is integrated within 0°≤θ≤360° to obtain the full-circle signal integral value B of the sling cross section. x-maxS Value, according to B x-maxS -α relationship diagram, the circumferential corrosion rate α is obtained; The module for calculating the central angle of circumferential corrosion is used to calculate the integral value B of the full-circumference signal of the cross section of the sling. x-maxS Obtaining a processed value s, determining a processed value l of the circumferential corrosion center angle L according to the sl relationship diagram, and then obtaining the circumferential corrosion center angle L according to an inverse formula of the processed value l of the circumferential corrosion center angle L; The circumferential corrosion depth calculation module is used to determine the circumferential corrosion depth h by combining the circumferential corrosion rate α and the circumferential corrosion center angle L.

Images