CN116359330A - Composite defect signal quantitative detection method - Google Patents
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Abstract
The invention discloses a composite defect signal quantitative detection method, which relates to the technical field of industrial nondestructive detection and is characterized in that: establishing a defect space leakage magnetic field, and establishing a three-dimensional rectangular coordinate system based on a magnetic charge model; establishing the magnetic charge density corresponding to the magnetic charge units with the segmented defect end faces, and determining the relation between the ferromagnetic material and the stress; establishing magnetic induction intensity and unit area corresponding to the magnetic charge units with the segmented defect end faces, and establishing total magnetic charge density, magnetic induction intensity and area of the defect end faces; and then solving the axial component and the radial component of the defect magnetic signal. The method fully considers the influence of stress on the defects of the ferromagnetic material, simulates and calculates the signal characteristics of the magnetic signals of the ferromagnetic material under the action of different defect stresses, and provides a more comprehensive, efficient and stable detection method for defect evaluation of the ferromagnetic member by the magnetic leakage detection technology.
Description
Technical field:
the invention relates to the technical field of industrial nondestructive testing, in particular to a composite defect detection signal quantification detection method.
The background technology is as follows:
in long-term engineering service, the ferromagnetic material is influenced by adverse factors such as external severe environment, improper manual operation and the like, and the material can have potential safety hazards such as cracks, corrosion, stress damage and the like. Once sudden dangerous accidents such as leakage and explosion occur, environmental pollution and energy loss can be caused, and the safety of people can be seriously threatened. Therefore, the method has great economic and social significance for ensuring the safe work of the ferromagnetic material. The current mainstream magnetic flux leakage detection technology uses a uniform magnetic charge model as a theoretical basis to calculate magnetic signals with different defect sizes, but the magnetic dipoles in the magnetic charges are affected by coulomb force, so that the corresponding magnetic charge distribution at the side wall of the defect is not ideal uniform distribution, and a larger error exists between an analysis value and an experimental measurement value. In addition, the influence of stress on magnetic signals is not considered in the existing magnetic leakage internal detection technology, the stress at the defect is far higher than the average stress of the material, and sudden accidents caused by stress damage cannot be avoided. The existing method can not realize accurate interpretation of the composite defects, and the quantization precision and the detection efficiency are affected.
The invention comprises the following steps:
the invention aims to:
the invention provides a composite defect signal quantification detection method, which aims to solve the problem that in the prior art, the distribution of magnetic charges corresponding to the side wall of a defect is not ideal and uniform because the magnetic dipoles in the magnetic charges are influenced by coulomb force; in addition, the stress at the defect is far higher than the average stress of the material, the quantitative relation between the stress and the magnetic signal is difficult to find in the prior art, so that a larger error exists between an analysis value and an experimental measurement value, and the problem that accurate interpretation of the composite defect cannot be realized is solved.
The technical scheme is as follows:
a composite defect signal quantitative detection method is characterized in that: the detection method comprises the following steps:
(1) Based on a magnetic charge model, taking a defect center as an origin, and establishing a three-dimensional rectangular coordinate system of a defect space leakage magnetic field to obtain the magnetic field intensity at any point of the defect space field;
(2) Dividing the rectangular defect magnetic charge surface into a plurality of magnetic charge units to obtain the magnetic charge density corresponding to the magnetic charge units at any position of the defect end surface;
(3) Considering the influence of stress on the magnetic signal at the defect end face, determining the relation between the relative magnetic permeability of the ferromagnetic material and the stress;
(4) The magnetic induction intensity of key physical quantity used as the characteristic of each point in the quantitative description magnetic field is obtained by establishing the magnetic induction intensity and unit area corresponding to the magnetic charge units with the segmented defect end faces;
(5) Accumulating the magnetic induction intensity and the unit area corresponding to each magnetic charge unit on the side wall of the defect in a matrix mode to obtain the total magnetic induction intensity and the total area at the end face of the defect;
(6) Obtaining the corresponding total magnetic charge density at the defect end face by carrying out column conversion according to the corresponding relation between the total magnetic induction density and the total area at the defect end face;
(7) Based on the non-uniform magnetic charge density calculation result at the defect end face, performing binary integration on the magnetic field of the defect end face to obtain an axial signal component and a radial signal component of the defect leakage magnetic field;
the method established according to the steps enables the magnetic charge distribution situation of the defect side wall to be more approximate to the magnetic charge distribution situation of the ferromagnetic material defect side wall under the actual working condition environment.
Establishing a defect space leakage magnetic field: based on the magnetic charge model, establishing a three-dimensional rectangular coordinate system; let the rectangular defect magnetic charge surface infinitesimal on the end surface be dy n ，dz n Any point P (x, y, z) in the spatial field is selected, and the strength of the magnetic field generated at the point can be expressed as:
wherein: ρ is the density of magnetic charges formed on the defective end face, μ 0 Is the magnetic permeability of the vacuum and is equal to the magnetic permeability of the vacuum,
is a unit direction vector;
establishing the magnetic charge density corresponding to the magnetic charge units with the segmented defect end faces: dividing a rectangular defect magnetic charge surface into a plurality of magnetic charge units, taking the defect center as an origin, setting the axial direction of the defect of the rectangular groove as an X axis, the radial direction as a Y axis and the circumferential direction as a Z axis; at this time, the magnetic charge density corresponding to the magnetic charge unit at any position of the defect end face can be expressed as:
wherein: 2D (2D) x ，2D z ，D y Respectively the axial length, circumferential width and radial depth of the rectangular groove. Mu (mu) r Is the relative permeability of the dielectric material; k=d x I, j represents the number of divided rows and columns, and the (K, i, j) coordinates represent the position of the magnetic charge unit in the defect space region;
determining the relationship between ferromagnetic material and stress can be expressed as:
wherein: sigma is stress, man is hysteresis-free magnetization intensity, ms is saturation magnetization intensity, he is effective magnetic field, alpha is magnetic domain coupling coefficient, a is material programming constant, and xi is unit volume energy measurement factor;
establishing magnetic induction intensity and unit area corresponding to the magnetic charge units with the segmented defect end faces: the magnetic induction intensity B is taken as a key physical quantity for quantitatively describing the characteristics of each point in the magnetic field, and the magnetic induction intensity corresponding to the magnetic charge unit at any position can be expressed as follows:
B K,i,j ＝4π*ρ(K,i,j)*S(K,i,j) (4)
wherein: s (K, i, j) represents the magnetic charge unit area of the position coordinates at the defect end face;
s is extended as follows:
establishing the total magnetic charge density, magnetic induction intensity and area of the defect end face: accumulating the magnetic charge density corresponding to each magnetic charge unit on the side wall of the defect in a matrix mode to obtain the total magnetic charge density at the end face of the defect, wherein the total magnetic induction density and the total area can be expressed as the following formula:
solving the total magnetic charge density of the defect end face: converting equations (6), (7) and (8) into a form of matrix product:
further converting the formula (9) through a matrix transformation rule to obtain the total magnetic charge density rho corresponding to the defect end face total ：
Solving the axial component and the radial component of the defect magnetic signal: the defect range of the rectangular side wall is from-Dy to 0 in the Y-axis direction, and from-Dz to Dz in the Z-axis direction, binary integration is carried out on the magnetic field H of the defect end face, and an axial signal component Hx and a radial signal component Hy of the defect leakage magnetic field are respectively obtained;
the advantages and effects:
the invention establishes a mathematical analysis model of the composite defect magnetic signal based on the magnetic charge theory. The signal characteristics of the magnetic signals of the ferromagnetic material under the action of different defect sizes and stresses are simulated, the corresponding relation between the magnetic signals and the ferromagnetic material under the action of different defect sizes and stresses is calculated, and a high-efficiency and stable detection method is provided for the service life assessment of the ferromagnetic member by the magnetic leakage detection technology.
Drawings
FIG. 1 is a schematic diagram of the magnetic flux leakage detection technology according to the present invention;
FIG. 2 is a schematic diagram of the distribution of defective magnetic charges according to the present invention;
FIG. 3 is a graph showing signal distribution for different defect depth sizes according to the present invention;
FIG. 4 is a graph showing the signal variation corresponding to different defect depth sizes according to the present invention;
FIG. 5 is a graph showing signal distribution for different defect width sizes according to the present invention;
FIG. 6 is a graph showing signal variation corresponding to different defect width sizes according to the present invention;
FIG. 7 is a graph showing signal distribution for different defect stresses according to the present invention;
FIG. 8 is a graph showing the signal variation corresponding to different defect stresses according to the present invention;
FIG. 9 is a graph of axial signal data acquisition for experimental sample 1 of the present invention;
FIG. 10 is a graph of radial signal data acquisition for experimental sample 1 of the present invention;
FIG. 11 is a graph of stress versus magnetic signal for experimental sample 2 of the present invention.
Specific embodiments;
the invention aims to provide a ferromagnetic material composite defect signal quantification detection method, which can effectively solve the problem of larger error between an analysis calculated value and an experimental measured value, realize accurate quantification of magnetic signals under the actions of different defect sizes and stresses and improve detection precision and detection quality.
The detection method comprises the following steps:
(1) Based on a magnetic charge model, taking a defect center as an origin, and establishing a three-dimensional rectangular coordinate system of a defect space leakage magnetic field to obtain the magnetic field intensity at any point of the defect space field;
(2) Dividing the rectangular defect magnetic charge surface into a plurality of magnetic charge units to obtain the magnetic charge density corresponding to the magnetic charge units at any position of the defect end surface;
(3) Considering the influence of stress on the magnetic signal at the defect end face, determining the relation between the relative magnetic permeability of the ferromagnetic material and the stress;
(4) The magnetic induction intensity of key physical quantity used as the characteristic of each point in the quantitative description magnetic field is obtained by establishing the magnetic induction intensity and unit area corresponding to the magnetic charge units with the segmented defect end faces;
(5) Accumulating the magnetic induction intensity and the unit area corresponding to each magnetic charge unit on the side wall of the defect in a matrix mode to obtain the total magnetic induction intensity and the total area at the end face of the defect;
(6) Obtaining the corresponding total magnetic charge density at the defect end face by carrying out column conversion according to the corresponding relation between the total magnetic induction density and the total area at the defect end face;
(7) Based on the non-uniform magnetic charge density calculation result at the defect end face, performing binary integration on the magnetic field of the defect end face to obtain an axial signal component and a radial signal component of the defect leakage magnetic field;
the method established according to the steps enables the magnetic charge distribution situation of the defect side wall to be more approximate to the magnetic charge distribution situation of the ferromagnetic material defect side wall under the actual working condition environment.
Establishing a defect space leakage magnetic field: based on the magnetic charge model, establishing a three-dimensional rectangular coordinate system; let the rectangular defect magnetic charge surface infinitesimal on the end surface be dy n ，dz n Any point P (x, y, z) in the spatial field is selected, and the strength of the magnetic field generated at the point can be expressed as:
wherein: ρ is the density of magnetic charges formed on the defective end face, μ 0 Is the magnetic permeability of the vacuum and is equal to the magnetic permeability of the vacuum,
is a unit direction vector;
establishing the magnetic charge density corresponding to the magnetic charge units with the segmented defect end faces: dividing a rectangular defect magnetic charge surface into a plurality of magnetic charge units, taking the defect center as an origin, setting the axial direction of the defect of the rectangular groove as an X axis, the radial direction as a Y axis and the circumferential direction as a Z axis; at this time, the magnetic charge density corresponding to the magnetic charge unit at any position of the defect end face can be expressed as:
wherein: 2D (2D) x ，2D z ，D y Respectively the axial length, circumferential width and radial depth of the rectangular groove. Mu (mu) r Is the relative permeability of the dielectric material; k=d x I, j represents the number of divided rows and columns, and the (K, i, j) coordinates represent the position of the magnetic charge unit in the defect space region;
determining the relationship between the relative permeability and stress of a ferromagnetic material can be expressed as:
wherein: sigma is stress, man is hysteresis-free magnetization intensity, ms is saturation magnetization intensity, he is effective magnetic field, alpha is magnetic domain coupling coefficient, a is material programming constant, and xi is unit volume energy measurement factor;
establishing magnetic induction intensity and unit area corresponding to the magnetic charge units with the segmented defect end faces: the magnetic induction intensity B is taken as a key physical quantity for quantitatively describing the characteristics of each point in the magnetic field, and the magnetic induction intensity corresponding to the magnetic charge unit at any position can be expressed as follows:
B K,i,j ＝4π*ρ(K,i,j)*S(K,i,j) (4)
wherein: s (K, i, j) represents the magnetic charge unit area of the position coordinates at the defect end face;
s is extended as follows:
establishing the total magnetic charge density, magnetic induction intensity and area of the defect end face: accumulating the magnetic charge density corresponding to each magnetic charge unit on the side wall of the defect in a matrix mode to obtain the total magnetic charge density at the end face of the defect, wherein the total magnetic induction density and the total area can be expressed as the following formula:
solving the total magnetic charge density of the defect end face: converting equations (6), (7) and (8) into a form of matrix product:
further converting the formula (9) through a matrix transformation rule to obtain the total magnetic charge density rho corresponding to the defect end face total ：
Solving the axial component and the radial component of the defect magnetic signal: the defect range of the rectangular side wall is from-Dy to 0 in the Y-axis direction, and from-Dz to Dz in the Z-axis direction, binary integration is carried out on the magnetic field H of the defect end face, and an axial signal component Hx and a radial signal component Hy of the defect leakage magnetic field are respectively obtained;
by the method, a space leakage magnetic field detection mathematical analysis model is established by firstly establishing non-uniform distribution of magnetic charges on the end face of the defect, so that a ferromagnetic material magnetic signal result and an experimental measurement value calculated by analysis are more accurate, quantization errors are reduced, detection efficiency is improved, and accurate interpretation of the defect of the ferromagnetic material is realized.
The method fully considers the influence of stress on the defects of the ferromagnetic material, simulates and calculates the signal characteristics of the magnetic signals of the ferromagnetic material under the action of different defect stresses, and provides a more comprehensive, efficient and stable detection method for defect evaluation of the ferromagnetic member by the magnetic leakage detection technology.
The invention is described in detail in the following figures:
FIG. 1 is a schematic diagram of the magnetic flux leakage detection technology according to the present invention. The schematic diagram comprises a pipeline 1, magnetic lines 2, a mileage wheel 3, a fixed support 4, a leather cup 5, a universal joint 6, a steel brush 7, a probe 8, a leakage magnetic field 9 and a defect 10. The magnetic flux leakage inner detector consists of a mileage wheel 3, a fixed support 4, a leather cup 5, a universal joint 6, a steel brush 7 and a probe 8.
When the oil gas pipeline is excited and magnetized by the outside, if the detected pipeline has defects, the detected pipeline is mainly filled with air, oil products and other impurities, compared with ferromagnetic materials, the magnetic permeability of the defect is smaller, the magnetic resistance is larger, magnetic lines of force bypass the defect of low magnetic permeability, and magnetic lines of force leak from two sides of the defect along the magnetization direction, so that a defect leakage magnetic field is generated. At the moment, the three-dimensional ultra-high definition probe in the pipeline magnetic flux leakage inner detector can collect and store defect signals and then analyze the defect signals, and the damage of the pipeline defects is evaluated. The whole process is the working principle of the pipeline magnetic flux leakage internal detection technology.
Fig. 2 is a schematic diagram of defect magnetic charges distribution provided by the present invention. The schematic includes positive magnetic charges 11, defects 12, a tube 13, negative magnetic charges 14, and defect sidewall magnetic charge distributions 15.
In the actual detection process, the tube body is magnetized from the outside to reach a magnetic saturation state, and after the magnetic dipoles in the magnetic charges are excited, the original stable magnetic charges on the side wall of the defect can deviate due to the influence of coulomb force, and the distribution condition corresponding to the stable magnetic charges on the side wall of the defect is not ideal and uniform.
FIG. 3 is a graph showing signal distribution for different defect depth sizes according to the present invention. The distribution diagram comprises a map of axial component distribution (a) of the defect magnetic leakage signal and a map of radial component distribution (b) of the defect magnetic leakage signal.
The axial length of the defect size is 10mm, the circumferential width is 10mm, the radial depth variation range is 2-7 mm, and the increment is 1mm. The excitation intensity of the external magnetic field is 15,000A/m, and the detector lift-off value is 2mm. When other conditions are constant, as the defect depth increases, the corresponding leakage signal component increases and the waveform changes are uniform. The axial signal components are distributed in an axisymmetric state, the radial signal components are distributed in a sinusoidal fluctuation state, and the axial signal components are distributed in a crest trough.
FIG. 4 is a graph showing the signal variation corresponding to different defect depth sizes according to the present invention. The profile includes a plot of the defect axial peak signal component variation (a) and a plot of the defect radial peak signal component variation (b).
When other conditions are constant, the area of the magnetic charge accumulation area of the side wall of the defect is increased along with the increase of the depth of the defect, the axial signal characteristic value component and the radial signal characteristic value component are increased in a nonlinear manner, and the change trend is changed according to an exponential function.
FIG. 5 is a graph showing signal distribution for different defect width sizes according to the present invention. The distribution diagram comprises a map of axial component distribution (a) of the defect magnetic leakage signal and a map of radial component distribution (b) of the defect magnetic leakage signal.
The axial length of the defect size is 15mm, the radial depth is 5mm, the circumferential width is 5-10 mm, and the increment is 1mm. The excitation intensity of the external magnetic field is 15,000A/m, and the detector lift-off value is 2mm. When other conditions are constant, as the defect width increases, the area of the magnetic charge accumulation area on the side wall of the defect increases, the corresponding magnetic leakage signal component increases, and the waveform changes consistently. The axial signal component has extreme values, is left and right with double peaks, is distributed in an axisymmetric state, and the radial signal component has wave peaks and wave troughs and is distributed in a sinusoidal fluctuation state.
FIG. 6 is a graph showing the signal variation corresponding to different defect depth sizes according to the present invention. The profile includes a plot of the defect axial extremum signal component variation (a) and a plot of the defect radial peak-to-peak signal component variation (b).
When other conditions are constant, the area of the magnetic charge accumulation area of the side wall of the defect is increased along with the increase of the width of the defect, the axial signal characteristic value component and the radial signal characteristic value component are increased in a nonlinear manner, and the change trend is changed according to an exponential function.
FIG. 7 is a graph showing signal distribution for different defect stresses according to the present invention. The distribution diagram comprises a map of axial component distribution (a) of the defect magnetic leakage signal and a map of radial component distribution (b) of the defect magnetic leakage signal.
The axial length of the defect size is 5mm, the radial depth is 5mm, the circumferential width variation range is 10mm, the stress variation range is 0-3Mpa, and the increment is 0.5Mpa. The excitation intensity of the external magnetic field is 15,000A/m, and the detector lift-off value is 2mm. When other conditions are constant, as the defect stress increases, the corresponding leakage signal component decreases and the waveform changes are uniform. The axial signal components have single peaks and are distributed in an axisymmetric state, and the radial signal components have wave crests and wave troughs and are distributed in a sinusoidal fluctuation state.
FIG. 8 is a graph showing the signal variation corresponding to different defect stresses according to the present invention. The profile includes a plot of the defect axial peak signal component variation (a) and a plot of the defect radial peak signal component variation (b).
When other conditions are constant, the relative magnetic permeability of the ferromagnetic material is reduced along with the increase of the defect stress, the axial signal characteristic value component and the radial signal characteristic value component are in nonlinear decline, and the change trend is consistent with the change of an exponential function.
Fig. 9 is a graph of axial signal data acquisition for experimental sample 1 of the present invention. The experimental data acquisition chart is an axial signal data acquisition chart of the experimental samples 1-X70 steel test pieces with different defect sizes. The graph includes axial signal data acquisition figures 1-4 with defect depth (0.64,1.21,2.45,4.63) in sequence and the graph includes axial signal data acquisition figures 5-8 with defect width (10, 20, 30, 40) in sequence.
Fig. 10 is a graph of radial signal data acquisition for experimental sample 1 of the present invention. The experimental data acquisition chart is a radial signal data acquisition chart of the experimental samples 1-X70 steel test piece with different defect sizes. The graph includes radial signal data acquisition figures 1-4 for defect depths (0.64,1.21,2.45,4.63) in order and radial signal data acquisition figures 5-8 for defect widths (10, 20, 30, 40) in order.
FIG. 11 is a graph of stress versus magnetic signal for experimental sample 2 of the present invention. The experimental data acquisition chart is a signal chart of the experimental samples 2-Q235 steel test piece under different stresses. The graph comprises an axial signal data graph (a) graph under different stresses and a radial signal data graph (b) graph under different stresses.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings.
Claims (8)
1. A composite defect signal quantitative detection method is characterized in that: the detection method comprises the following steps:
(1) Based on a magnetic charge model, taking a defect center as an origin, and establishing a three-dimensional rectangular coordinate system of a defect space leakage magnetic field to obtain the magnetic field intensity at any point of the defect space field;
(2) Dividing the rectangular defect magnetic charge surface into a plurality of magnetic charge units to obtain the magnetic charge density corresponding to the magnetic charge units at any position of the defect end surface;
(3) Considering the influence of stress on the magnetic signal at the defect end face, determining the relation between the relative magnetic permeability of the ferromagnetic material and the stress;
(4) The magnetic induction intensity of key physical quantity used as the characteristic of each point in the quantitative description magnetic field is obtained by establishing the magnetic induction intensity and unit area corresponding to the magnetic charge units with the segmented defect end faces;
(5) Accumulating the magnetic induction intensity and the unit area corresponding to each magnetic charge unit on the side wall of the defect in a matrix mode to obtain the total magnetic induction intensity and the total area at the end face of the defect;
(6) Obtaining the corresponding total magnetic charge density at the defect end face by carrying out column conversion according to the corresponding relation between the total magnetic induction density and the total area at the defect end face;
(7) Based on the non-uniform magnetic charge density calculation result at the defect end face, performing binary integration on the magnetic field of the defect end face to obtain an axial signal component and a radial signal component of the defect leakage magnetic field;
the method established according to the steps enables the magnetic charge distribution situation of the defect side wall to be more approximate to the magnetic charge distribution situation of the ferromagnetic material defect side wall under the actual working condition environment.
2. The method for quantitatively detecting composite defect signals according to claim 1, wherein: step (1) establishing a defect space leakage magnetic field: based on the magnetic charge model, establishing a three-dimensional rectangular coordinate system; let the rectangular defect magnetic charge surface infinitesimal on the end surface be dy n ，dz n Any point P (x, y, z) in the spatial field is selected, and the strength of the magnetic field generated at the point can be expressed as:
wherein: ρ is the density of magnetic charges formed on the defective end face, μ 0 Is the magnetic permeability of the vacuum and is equal to the magnetic permeability of the vacuum,
is a unit direction vector.
3. The method for quantitatively detecting composite defect signals according to claim 1, wherein: step (2) establishing the magnetic charge density corresponding to the magnetic charge units with the segmented defect end faces: dividing a rectangular defect magnetic charge surface into a plurality of magnetic charge units, taking the defect center as an origin, setting the axial direction of the defect of the rectangular groove as an X axis, the radial direction as a Y axis and the circumferential direction as a Z axis; at this time, the magnetic charge density corresponding to the magnetic charge unit at any position of the defect end face can be expressed as:
wherein: 2D (2D) x ，2D z ，D y Respectively representing the axial length, the circumferential width and the radial depth of the rectangular groove; mu (mu) r Is the relative permeability of the dielectric material; k=d x I, j represents the number of rows and columns of the segment, and the (K, i, j) coordinates represent the location of the magnetic charge unit within the defect space region.
4. The method for quantitatively detecting composite defect signals according to claim 1, wherein: step (3) of determining the relationship between the relative permeability and stress of the ferromagnetic material can be expressed as:
wherein: sigma is stress, man is hysteresis-free magnetization, ms is saturation magnetization, he is effective magnetic field, alpha is magnetic domain coupling coefficient, a is material programming constant, and ζ is energy measurement factor per unit volume.
5. The method for quantitatively detecting composite defect signals according to claim 1, wherein: step (4) establishing magnetic induction intensity and unit area corresponding to the magnetic charge units with the segmented defect end faces: the magnetic induction intensity B is taken as a key physical quantity for quantitatively describing the characteristics of each point in the magnetic field, and the magnetic induction intensity corresponding to the magnetic charge unit at any position can be expressed as follows:
B K,i,j ＝4π*ρ(K,i,j)*S(K,i,j) (4)
wherein: s (K, i, j) represents the magnetic charge unit area of the position coordinates at the defect end face;
s is extended as follows:
6. the method for quantitatively detecting composite defect signals according to claim 1, wherein: step (5) establishing the total magnetic charge density of the defect end face, and the magnetic induction intensity and area: accumulating the magnetic charge density corresponding to each magnetic charge unit on the side wall of the defect in a matrix mode to obtain the total magnetic charge density at the end face of the defect, wherein the total magnetic induction density and the total area can be expressed as the following formula:
7. the method for quantitatively detecting composite defect signals according to claim 1, wherein: step (6) solving the total magnetic charge density of the defect end face: converting equations (6), (7) and (8) into a form of matrix product:
further converting the formula (9) through a matrix transformation rule to obtain the total magnetic charge density rho corresponding to the defect end face total ：
8. The method for quantitatively detecting composite defect signals according to claim 1, wherein: step (7) solving the axial component and the radial component of the defect magnetic signal: the defect range of the rectangular side wall is from-Dy to 0 in the Y-axis direction, and from-Dz to Dz in the Z-axis direction, binary integration is carried out on the magnetic field H of the defect end face, and an axial signal component Hx and a radial signal component Hy of the defect leakage magnetic field are respectively obtained;
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| CN116702564A (en) * | 2023-07-14 | 2023-09-05 | 西南石油大学 | Self-leakage magnetic field calculation method considering pipeline characteristics |
| CN116735700A (en) * | 2023-08-08 | 2023-09-12 | 国机传感科技有限公司 | Pipeline defect stress composite detection sensor and detection method |
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| CN116702564A (en) * | 2023-07-14 | 2023-09-05 | 西南石油大学 | Self-leakage magnetic field calculation method considering pipeline characteristics |
| CN116702564B (en) * | 2023-07-14 | 2023-09-29 | 西南石油大学 | Self-leakage magnetic field calculation method considering pipeline characteristics |
| CN116735700A (en) * | 2023-08-08 | 2023-09-12 | 国机传感科技有限公司 | Pipeline defect stress composite detection sensor and detection method |
| CN116735700B (en) * | 2023-08-08 | 2023-12-08 | 沈阳仪表科学研究院有限公司 | Pipeline defect stress composite detection sensor and detection method |
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