Method and device for determining force-magnetic coupling model, electronic equipment and storage medium

Abstract

The application discloses a method and device for determining a force-magnetic coupling model, electronic equipment and a storage medium, relates to the technical field of pipeline stress analysis, and aims to accurately determine pipeline stress. The method comprises the following steps: determining a first model for representing a theoretical relationship between stress and relative magnetic permeability of a test plate; determining actual relative magnetic permeability based on actual stress measured in a static calibration test, actual magnetic induction intensity corresponding to the actual stress, and the first model; determining a target ratio between the actual magnetic induction intensity and an initial magnetic induction intensity; establishing a second model for representing a fitting relationship between the actual relative magnetic permeability and the target ratio; obtaining a third model for representing a fitting relationship between predicted stress and the target ratio based on the first model and the second model; and correcting the third model based on a corresponding relationship between lift-off values and magnetic field attenuation coefficients to obtain the force-magnetic coupling model.

Description

Technical Field

[0001] This application relates to the field of pipeline stress analysis technology, and in particular to a method, apparatus, electronic device and storage medium for determining a force-magnetic coupling model. Background Technology

[0002] Ferromagnetic metal components (such as oil and gas pipelines and industrial load-bearing structures) are widely used, but during their use, they are susceptible to impact loads, media corrosion, cyclic fatigue, and other factors, gradually leading to stress concentration or micro-damage inside. If these damages are not identified in a timely and accurate manner, they may cause structural failure or even major safety accidents. Metal magnetic memory testing technology, as a non-destructive testing method based on the magnetic field distortion of the ferromagnetic material surface, can achieve early damage warning by capturing changes in the magnetic field signal in areas of stress concentration.

[0003] Currently, most metal magnetic memory detection technologies are limited to establishing a qualitative or semi-quantitative correlation between pipeline stress and detection signals. They can only determine that "stress concentration exists" but cannot accurately calculate stress values.

[0004] Therefore, it is necessary to establish a force-magnetic coupling model that can accurately determine pipeline stress, providing a technical solution for the precise assessment of stress concentration areas in ferromagnetic pipelines, thereby ensuring the safety and stability of pipeline operation. Summary of the Invention

[0005] The purpose of this application is to provide a method, apparatus, electronic device and storage medium for determining a force-magnetic coupling model, with the aim of accurately determining pipeline stress.

[0006] To achieve the above objectives, this application adopts the following technical solution: Firstly, this application provides a method for determining a force-magnetic coupling model, comprising: A first model is established to characterize the theoretical relationship between stress and relative permeability of the test plate. The actual stress and the actual magnetic flux density corresponding to the actual stress are obtained in the static calibration test. Based on the actual stress and the actual magnetic flux density corresponding to the actual stress, and the first model, the actual relative permeability is determined. Obtain the initial magnetic induction intensity of the test plate and determine the target ratio between the actual magnetic induction intensity and the initial magnetic induction intensity; A second model is established to characterize the fitting relationship between the actual relative permeability and the target ratio; Based on the second model and the first model, a third model is obtained to characterize the fitting relationship between the predicted stress and the target ratio; The correspondence between the lift-off value and the magnetic field attenuation coefficient is obtained, and the third model is modified based on the correspondence between the lift-off value and the magnetic field attenuation coefficient to obtain the force-magnetic coupling model.

[0007] The method for determining the force-magnetic coupling model provided in this application provides a basis for the correlation between stress and magnetic properties by determining a first model. By determining a second model, the theoretical relationship is correlated with experimental data, and the influence of the initial magnetic induction intensity on the correlation accuracy is eliminated. The third model derived from the first and second models can characterize the fitting relationship between the predicted stress and the target ratio. Therefore, stress can be predicted using easily measurable magnetic induction intensity and the initial magnetic induction intensity, without the need for complex intermediate calculations of magnetic permeability, resulting in high stress calculation efficiency. Furthermore, the third model is corrected by the correspondence between the lift-off value and the magnetic field attenuation coefficient. This corrected force-magnetic coupling model eliminates the interference of the lift-off value, improves the accuracy and precision of pipeline stress detection, and provides a reference for the quantitative assessment of pipeline stress concentration areas.

[0008] In some embodiments, determining a first model includes: determining a hysteresis curve of a test plate; determining the saturation magnetic induction intensity, initial relative permeability, and saturation magnetic induction coefficient of the test plate based on the hysteresis curve; and determining a first model based on the saturation magnetic induction intensity, initial relative permeability, and saturation magnetic induction coefficient of the test plate.

[0009] In some embodiments, a strain gauge is disposed on one side of the test plate and a magnetic sensor is disposed on the other side. The placement positions of the strain gauge and the magnetic sensor correspond. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. During static calibration testing, the magnetic sensor includes a first magnetic sensor and a second magnetic sensor. The first magnetic sensor is used to measure the magnetic induction intensity at its original placement position when the tensile machine stops stretching the test plate, and the second magnetic sensor is used to measure the magnetic induction intensity at various positions on the test plate when the tensile machine stops stretching the test plate. The static calibration test includes: before the tensile machine is started, recording the initial magnetic induction intensity of the test plate measured by the first magnetic sensor and the second magnetic sensor; after the tensile machine loads a preset load variable and stops loading, the strain gauge measures the stress, and the first and second magnetic sensors measure the magnetic induction intensity; after the strain gauge, the first magnetic sensor, and the second magnetic sensor have completed their measurements, the tensile machine loads the preset load variable until the load value of the tensile machine reaches the preset load value.

[0010] In some embodiments, the third model is modified based on the correspondence between the lift-off value and the magnetic field attenuation coefficient to obtain a force-magnetic coupling model, including: obtaining the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress; and modifying the third model based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, as well as the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress to obtain a force-magnetic coupling model.

[0011] In some embodiments, a strain gauge is provided on one side of the test plate and a magnetic sensor is provided on the other side. The positions of the strain gauge and the magnetic sensor correspond. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. The dynamic calibration test includes: before the tensile machine is started, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor and the magnetic induction intensity when there is no stress; after the tensile machine is started, continuous loading is carried out, the magnetic sensor continuously measures the magnetic induction intensity at the original setting position, and the strain gauge continuously measures the stress, until the load value of the tensile machine reaches the preset load value.

[0012] In some embodiments, the method further includes: obtaining the actual stress measured in a static test and the actual magnetic flux density corresponding to the actual stress; verifying the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the static test and the actual magnetic flux density corresponding to the actual stress; and / or obtaining the actual stress measured in a dynamic test and the actual magnetic flux density corresponding to the actual stress; verifying the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the dynamic test and the actual magnetic flux density corresponding to the actual stress.

[0013] In some embodiments, the static testing includes: before starting the tensile testing machine, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor; after the tensile testing machine loads a preset load variable and then stops loading, the strain gauge measures the stress, and the magnetic sensor measures the magnetic induction intensity; after the strain gauge and magnetic sensor measurements are completed, the tensile testing machine loads a preset load variable until the load value of the tensile testing machine reaches the preset load value; the steps of the dynamic testing are the same as those of the dynamic calibration testing.

[0014] Secondly, this application provides a device for determining a force-magnetic coupling model, comprising: The processing module is used to determine the first model for characterizing the theoretical relationship between stress and relative permeability of the test plate. The acquisition module is used to acquire the actual stress measured in the static calibration test and the actual magnetic induction intensity corresponding to the actual stress. The processing module is also used to determine the actual relative permeability based on the corresponding actual stress and actual magnetic induction intensity, as well as the first model. The acquisition module is also used to acquire the initial magnetic induction intensity of the test plate; The processing module is also used to determine the target ratio between the actual magnetic flux density and the initial magnetic flux density; The processing module is also used to establish a second model to characterize the fitting relationship between the actual relative permeability and the target ratio; The processing module is also used to obtain a third model based on the second model and the first model to characterize the fitting relationship between the predicted stress and the target ratio; The acquisition module is also used to obtain the correspondence between the lift-off value and the magnetic field attenuation coefficient; The processing module is also used to correct the third model based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, so as to obtain the force-magnetic coupling model.

[0015] In some embodiments, the processing module is specifically used to: determine the hysteresis curve of the test plate; determine the saturation magnetic induction intensity, initial relative permeability and saturation magnetic induction coefficient of the test plate based on the hysteresis curve; and determine the first model based on the saturation magnetic induction intensity, initial relative permeability and saturation magnetic induction coefficient of the test plate.

[0016] In some embodiments, a strain gauge is disposed on one side of the test plate and a magnetic sensor is disposed on the other side. The placement positions of the strain gauge and the magnetic sensor correspond. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. During static calibration testing, the magnetic sensor includes a first magnetic sensor and a second magnetic sensor. The first magnetic sensor is used to measure the magnetic induction intensity at its original placement position when the tensile machine stops stretching the test plate, and the second magnetic sensor is used to measure the magnetic induction intensity at various positions on the test plate when the tensile machine stops stretching the test plate. The static calibration test includes: before the tensile machine is started, recording the initial magnetic induction intensity of the test plate measured by the first magnetic sensor and the second magnetic sensor; after the tensile machine loads a preset load variable and stops loading, the strain gauge measures the stress, and the first and second magnetic sensors measure the magnetic induction intensity; after the strain gauge, the first magnetic sensor, and the second magnetic sensor have completed their measurements, the tensile machine loads the preset load variable until the load value of the tensile machine reaches the preset load value.

[0017] In some embodiments, the acquisition module is further configured to acquire the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress; the processing module is further configured to modify the third model based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, as well as the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress, to obtain the force-magnetic coupling model.

[0018] In some embodiments, a strain gauge is provided on one side of the test plate and a magnetic sensor is provided on the other side. The positions of the strain gauge and the magnetic sensor correspond. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. The dynamic calibration test includes: before the tensile machine is started, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor and the magnetic induction intensity when there is no stress; after the tensile machine is started, continuous loading is carried out, the magnetic sensor continuously measures the magnetic induction intensity at the original setting position, and the strain gauge continuously measures the stress, until the load value of the tensile machine reaches the preset load value.

[0019] In some embodiments, the acquisition module is further configured to acquire the actual stress measured in the static test and the actual magnetic flux density corresponding to the actual stress; the processing module is further configured to verify the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the static test and the actual magnetic flux density corresponding to the actual stress; and / or, the acquisition module is further configured to acquire the actual stress measured in the dynamic test and the actual magnetic flux density corresponding to the actual stress; the processing module is further configured to verify the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the dynamic test and the actual magnetic flux density corresponding to the actual stress.

[0020] In some embodiments, the static testing includes: before starting the tensile testing machine, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor; after the tensile testing machine loads a preset load variable and then stops loading, the strain gauge measures the stress, and the magnetic sensor measures the magnetic induction intensity; after the strain gauge and magnetic sensor measurements are completed, the tensile testing machine loads a preset load variable until the load value of the tensile testing machine reaches the preset load value; the steps of the dynamic testing are the same as those of the dynamic calibration testing.

[0021] Thirdly, this application provides an electronic device, comprising: one or more processors; one or more memories; wherein the one or more memories are used to store computer program code, the computer program code including computer instructions, and when the one or more processors execute the computer instructions, the electronic device executes any of the force-magnetic coupling model determination methods provided in the first aspect above.

[0022] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions that, when executed on a computer, cause the computer to perform any of the force-magnetic coupling model determination methods provided in the first aspect.

[0023] Fifthly, this application provides a computer program product including computer instructions that, when executed on an electronic device, cause the electronic device to perform any of the force-magnetic coupling model determination methods provided in the first aspect.

[0024] For a detailed description of the second to fifth aspects and their various implementations in this application, please refer to the detailed description in the first aspect and its various implementations; and for a detailed analysis of the beneficial effects of the second to fifth aspects and their various implementations in the first aspect and its various implementations, please refer to the beneficial effect analysis in the first aspect and its various implementations, which will not be repeated here.

[0025] These or other aspects of this application will become more readily apparent in the following description. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of the experimental platform to which the method for determining a force-magnetic coupling model provided in this application embodiment is applicable; Figure 2 This is a schematic diagram of the strain gauge placement position provided in an embodiment of this application; Figure 3 This is a schematic diagram of the magnetic sensor mounting position provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a computing device provided in an embodiment of this application; Figure 5 A flowchart illustrating a method for determining a force-magnetic coupling model provided in an embodiment of this application; Figure 6 A schematic diagram of a static calibration test provided for an embodiment of this application; Figure 7 A schematic diagram illustrating a process for determining predicted stress based on a force-magnetic coupling model, provided for an embodiment of this application; Figure 8 A schematic diagram of a dynamic calibration test provided for an embodiment of this application; Figure 9 A schematic diagram of the dimensions of a standard specimen provided in an embodiment of this application; Figure 10 This is a schematic diagram of the dimensions of a non-standard sample provided in an embodiment of this application; Figure 11 A schematic diagram of stress changes during a static calibration test provided in this application embodiment; Figure 12 This application provides a schematic diagram of the change in magnetic induction intensity during a static calibration test. Figure 13 This application provides a schematic diagram of stress changes during a static testing test. Figure 14 This application provides a schematic diagram illustrating the trends of stress and magnetic induction intensity in a dynamic calibration test. Figure 15 This application provides a schematic diagram illustrating the trends of stress and magnetic induction intensity in a dynamic detection test. Figure 16 A sampling schematic diagram provided for an embodiment of this application; Figure 17 A schematic diagram of a fitting curve between relative permeability and target ratio provided in an embodiment of this application; Figure 18 A schematic diagram comparing a predicted stress curve and actual stress, provided for an embodiment of this application; Figure 19 A schematic diagram comparing a predicted stress curve and an actual stress curve, provided for an embodiment of this application; Figure 20 This is a schematic diagram of a device for determining a force-magnetic coupling model provided in an embodiment of this application. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or relative positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Unless otherwise specified, the above-mentioned orientational descriptions can be flexibly set in practical applications, provided that the relative positional relationships shown in the accompanying drawings are satisfied.

[0030] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "communication" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0032] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes that element.

[0033] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0034] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0035] Ferromagnetic metal components (such as oil and gas pipelines and industrial load-bearing structures) are widely used, but during their use, they are susceptible to impact loads, media corrosion, cyclic fatigue, and other factors, gradually leading to stress concentration or micro-damage inside. If these damages are not identified in a timely and accurate manner, they may cause structural failure or even major safety accidents. Metal magnetic memory testing technology, as a non-destructive testing method based on the magnetic field distortion of the ferromagnetic material surface, can achieve early damage warning by capturing changes in the magnetic field signal in areas of stress concentration.

[0036] Currently, most metal magnetic memory testing technologies are limited to establishing a qualitative or semi-quantitative correlation between pipeline stress and the detection signal. They can only determine the presence of stress concentration but cannot accurately calculate stress values. Due to the lack of a unified quantitative evaluation standard, it is difficult to compare and verify the test results obtained from different testing scenarios and different equipment.

[0037] Furthermore, the significant difference in magnetic permeability between air and ferromagnetic materials means that even a small change in the perpendicular distance between the sensor and the sample surface (i.e., the "lift-off value") can cause a drastic decrease in the measured magnetic flux density. Since magnetic flux density is a core factor in subsequent stress analysis, the error caused by the lift-off value has not been effectively eliminated. In addition, factors such as the initial magnetization state of the ferromagnetic material (e.g., residual magnetism from the manufacturing process), fluctuations in the geomagnetic field, and interference from artificial magnetic fields in industrial environments all affect the detection signal, exacerbating the bias in stress analysis and making it difficult to meet the accuracy and reliability requirements for pipeline stress detection in complex engineering scenarios.

[0038] Therefore, a force-magnetic coupling model is needed to achieve quantitative calculation of pipeline stress, providing a technical solution for accurate assessment of stress concentration areas in ferromagnetic pipelines, thereby ensuring the safety and stability of pipeline operation.

[0039] Based on this, this application provides a method for determining a force-magnetic coupling model. First, a first model is determined to characterize the theoretical relationship between stress and relative permeability of the test plate, providing a basis for the correlation between stress and magnetic properties. Then, based on the actual stress measured in the static calibration test and the corresponding actual magnetic flux density, along with the first model, the actual relative permeability is determined. Next, a target ratio between the actual magnetic flux density and the initial magnetic flux density is determined, establishing a second model to characterize the fitting relationship between the actual relative permeability and the target ratio. This correlates the theoretical relationship with the experimental data, eliminating the influence of the initial magnetic flux density on the correlation accuracy. Based on the second and first models, a third model is obtained to characterize the fitting relationship between the predicted stress and the target ratio. Stress can then be predicted using easily measurable magnetic flux density and the initial magnetic flux density, eliminating the need for complex intermediate calculations of permeability and improving stress calculation efficiency. Finally, based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, the third model is modified to obtain the force-magnetic coupling model, eliminating the interference of the lift-off value and improving the accuracy and precision of pipeline stress detection, providing a reference for the quantitative assessment of pipeline stress concentration areas.

[0040] like Figure 1 The diagram shows a schematic of the experimental platform to which the method for determining a force-magnetic coupling model provided in this application is applicable. The experimental platform includes a tensile testing machine.

[0041] The tensile testing machine includes an upper clamping section and a lower clamping section, which are used to fix the upper and lower ends of the test plate, respectively. When the tensile testing machine is working, the upper clamping section and the lower clamping section move in opposite directions to stretch the test plate.

[0042] For example, the tensile testing machine can be a tensile testing machine with a maximum rated load of 100 tons (t), which applies a maximum tensile force of 100 tons to the plate, ensuring that the equipment will not be overloaded during the test and guaranteeing the stability of the test on the plate.

[0043] In some embodiments, the tensile testing machine may include a contact extensometer for accurately measuring the "gauge length elongation" during the tensile testing of the test sheet. The extensometer is in direct contact with the surface of the test sheet to obtain deformation data, thereby enabling the calculation of the real-time strain of the test sheet based on the deformation data.

[0044] In some embodiments, the test platform further includes strain gauges for measuring the stress in the plate material. The number of strain gauges can be one or more.

[0045] like Figure 2 As shown, strain gauges are placed on the first surface of the test plate.

[0046] In some embodiments, the test platform further includes magnetic sensors for measuring the magnetic flux density of the test plate. The number of magnetic sensors corresponds to the number of strain gauges, and the magnetic sensors are positioned on the second surface of the test plate at locations corresponding to the strain gauge positions, according to preset lift-off values. The first and second surfaces of the test plate are opposite to each other.

[0047] For example, based on Figure 2 The strain gauge placement shown is such that the magnetic sensor placement on the second surface of the test plate can be as follows. Figure 3 As shown.

[0048] In some embodiments, the distance between the magnetic sensor and the test plate is a preset lift-off value, for example, a preset lift-off value of 10 mm.

[0049] In some embodiments, the magnetic sensor can be divided into a magnetic sensor for fixed measurement and a magnetic sensor for dynamic scanning measurement. The magnetic sensor for fixed measurement can record the magnetic flux density throughout the measurement process. The magnetic sensor for dynamic scanning measurement moves along the test area of ​​the test plate to detect the magnetic flux density and obtain a curve showing the change in magnetic flux density with scanning distance.

[0050] In some embodiments, the frequency at which the strain gauge measures stress is the same as the frequency at which the magnetic sensor measures magnetic flux density, and the strain gauge and the magnetic sensor are activated simultaneously. This ensures that stress and magnetic flux density are synchronized over time.

[0051] In some embodiments, the test platform further includes electronic equipment connected to strain gauges and magnetic sensors for receiving measurement data from the strain gauges and magnetic sensors respectively.

[0052] The electronic device establishes a first model, which characterizes the theoretical relationship between stress and relative permeability of the test plate. It acquires the actual stress and corresponding actual magnetic flux density measured in the static calibration test, and determines the actual relative permeability based on the measured stress, the actual magnetic flux density, and the first model. It acquires the initial magnetic flux density of the test plate and determines the target ratio between the actual magnetic flux density and the initial magnetic flux density. A second model is established to characterize the fitting relationship between the actual relative permeability and the target ratio. Based on the second and first models, a third model is obtained to characterize the fitting relationship between the predicted stress and the target ratio. The correspondence between the lift-off value and the magnetic field attenuation coefficient is acquired, and the third model is corrected based on this correspondence to obtain the force-magnetic coupling model.

[0053] When it is necessary to assess pipeline stress, simply measuring the pipeline's magnetic induction intensity is sufficient to obtain a reliable predicted stress based on a force-magnetic coupling model, providing a reference for the quantitative assessment of pipeline stress concentration areas.

[0054] In some embodiments, the test platform may also be equipped with a temperature and humidity control system to reduce the influence of ambient temperature and humidity on magnetic field measurements.

[0055] The structural design of the above-mentioned test platform can provide a reference for the study of the magnetic coupling law of tensile force in steel, and for quasi-static and dynamic tensile tests on plate specimens.

[0056] The hardware structure of electronic devices may include Figure 4 The components included in the computing device shown.

[0057] like Figure 4 As shown, the computing device may include a processor 101, a memory 102, a communication interface 103, and a bus 104. The processor 101, the memory 102, and the communication interface 103 can be connected via the bus 104.

[0058] Processor 101 is the control center of the computing device. It can be a single processor or a collective term for multiple processing elements. For example, processor 101 can be a general-purpose central processing unit (CPU) or other general-purpose processors. Among them, the general-purpose processor can be a microprocessor or any conventional processor.

[0059] As one embodiment, processor 101 may include one or more CPUs, for example Figure 4 CPU 0 and CPU 1 are shown in the diagram.

[0060] The memory 102 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.

[0061] In one possible implementation, the memory 102 can exist independently of the processor 101. The memory 102 can be connected to the processor 101 via a bus 104 and is used to store instructions or program code. When the processor 101 calls and executes the instructions or program code stored in the memory 102, it can implement the method for determining the force-magnetic coupling model provided in the embodiments of this application.

[0062] In another possible implementation, the memory 102 can also be integrated with the processor 101.

[0063] The communication interface 103 is used for connecting the computing device to other devices via a communication network, which may be Ethernet, radio access network (RAN), wireless local area network (WLAN), etc. The communication interface 103 may include a receiving unit for receiving data and a transmitting unit for transmitting data.

[0064] Bus 104 can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. This bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 4 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0065] It should be pointed out that, Figure 4 The structure shown does not constitute a limitation on the computing device, except Figure 4In addition to the components shown, the computing device may include more or fewer components than illustrated, or combine certain components, or have different component arrangements.

[0066] This application also provides a method for determining a force-magnetic coupling model, which can be executed by the aforementioned electronic device, such as... Figure 5 As shown, the method includes the following steps: S101. A first model is established to determine the theoretical relationship between stress and relative permeability of the test plate.

[0067] In some embodiments, step S101 may specifically be implemented as follows: determining the hysteresis curve of the test plate; determining the saturation magnetic induction intensity, initial relative permeability and saturation magnetic induction coefficient of the test plate based on the hysteresis curve; and determining the first model based on the saturation magnetic induction intensity, initial relative permeability and saturation magnetic induction coefficient of the test plate.

[0068] First, obtain the hysteresis loop data of the test plate under the action of an alternating magnetic field. The hysteresis loop includes a saturated hysteresis loop to reflect the relationship between energy loss and magnetic induction intensity change during the magnetization process of the material. Specifically, a hysteresis loop tester can be used to collect the response value of the corresponding magnetic induction intensity under the condition of gradually increasing magnetic field strength, and draw a closed hysteresis loop curve (hysteresis curve).

[0069] Furthermore, based on the hysteresis loop, the saturation magnetic flux density, initial relative permeability, and saturation magnetostriction coefficient of the test plate are determined. Among them, the saturation magnetic flux density is the maximum magnetic flux density value corresponding to the vertex of the hysteresis loop; the initial relative permeability is the relative permeability corresponding to the initial slope of the ratio of magnetic flux density to magnetic field strength in the initial segment of the hysteresis loop; the saturation magnetostriction coefficient is calculated by measuring the rate of change of material length under saturated magnetization and combining it with the magnetization intensity data.

[0070] Finally, based on the saturation magnetic induction intensity, initial relative permeability, and saturation magnetostriction coefficient of the test plate, a first model is constructed. The first model is used to characterize the magnetic performance response characteristics of the test plate under different stress conditions. The above parameters are used as input variables, and the functional relationship between magnetic induction intensity, permeability, and applied stress is established through mathematical modeling methods to achieve a quantitative description and prediction of the magnetomechanical coupling behavior of the material.

[0071] In some embodiments, based on the magnetomechanical effect, for isotropic ferromagnetic materials, when the direction of external stress is parallel to the magnetization direction, the stress energy generated inside the ferromagnetic material... It can be represented as: (Formula 1); in, The stress energy represents the energy required for an external force to change the magnetic state of a material; 'a' is a preset constant coefficient, which can be set based on crystal structure and magnetoelastic theory, such as 1.1, 1.5, 1.7, etc. This application does not limit this; for ease of explanation, the embodiments of this application are used as examples. For example; σ is the external stress, that is, the external force applied per unit area; θ is the magnetostriction coefficient, which measures the efficiency of the conversion between force and magnetism; θ is the angle between the direction of external stress and the direction of magnetization inside the material. It is a direction factor that reflects the degree of matching between the direction of the external force and the direction of magnetization (1 when parallel and 0 when perpendicular).

[0072] As can be understood, Formula 1 describes the stress energy generated in ferromagnetic materials under external force. The negative sign indicates that the system always tends towards the state of lowest energy, meaning that the magnetic domains inside the material will spontaneously adjust their direction to conform to the external force, thereby reducing the total energy. The formula shows that the greater the external force, the higher the mechanomagnetic conversion efficiency, and the more consistent the direction of the external force with the magnetization direction of the material, the greater the absolute value of the stress energy, and the more significant the change in the magnetic state of the material by the external force.

[0073] In some embodiments, since the magnetostriction coefficient under stress is an unknown parameter that cannot be directly measured, in order to compare this unknown quantity with macroscopic magnetic parameters that can be directly measured in experiments (such as the magnetic induction intensity B under no stress), T Magnetic induction intensity B under stress σ and saturation magnetic induction intensity B m Establish a quantitative relationship to eliminate the magnetostriction coefficient. It is necessary to use formulas (2) and (3) based on the molecular current model and Hooke's law as a bridge to finally derive the final result. The computable expression for this is: Specifically, based on the magnetization theory based on molecular currents and Hooke's law for ferromagnetic materials, we have: (Formula 2); (Formula 3); In Formula 2, N represents the number of magnetic domains per unit volume or the density coefficient related to molecular current, representing the characteristic parameters of the microscopic magnetic structure inside the material; Δx and Δy represent the size changes of the material's micro-units in two orthogonal directions, reflecting the changes in the material's microscopic geometric dimensions under stress. It is used to represent the magnetic induction intensity of ferromagnetic materials under stress-free conditions. It is the intrinsic magnetic state of the material when it is not subjected to external force and can be directly measured by a magnetic sensor. It is used to represent the magnetic induction intensity under external stress σ, which is the actual magnetic state of the material after being subjected to force, and can also be directly measured.

[0074] As can be seen from Formula 2, the geometric parameters (N, ...) of the material's microstructure... Δx, Δy) and macroscopically measurable magnetic parameters ( There is an equivalence relationship between them, thus linking unknown microscopic parameters with measurable macroscopic magnetic induction intensity.

[0075] In formula 3, It refers to the magnetostriction coefficient under saturation conditions. It is an intrinsic constant of the material, which can be determined experimentally and is a known quantity. It refers to the saturation magnetic induction intensity of ferromagnetic materials. It is the limiting magnetic induction intensity reached when the material is magnetized to the point that all magnetic domains are aligned in the same direction. It is an inherent property of the material itself and can be obtained by measuring the hysteresis curve.

[0076] As can be seen from Equation 3, under saturated magnetization, the geometric parameters (N, ...) of the material's microstructure are... Δx, Δy) are equal to the square of the saturation magnetic induction intensity ( 2 This relationship provides the basis for subsequently combining equations (2) and (3) and eliminating the microscopic parameters. Since the parameters under saturation are known and fixed, they can be used as a "reference standard" to calibrate the measured values ​​under stress.

[0077] Combining equations 2 and 3 above, we can obtain the magnetostriction coefficient under elastic stress. .

[0078] (Formula 4); Formula 4 can be used to determine the unknown parameter λ in formula (1) that cannot be directly measured. σ (Magnetostriction coefficient under stress) is converted into a combination of four known or measurable physical quantities: magnetic induction intensity B under no stress. T Magnetic induction intensity B under stress σ (Both can be directly measured by a magnetic sensor), the inherent saturation magnetic induction intensity B of the material. m and the material's inherent saturation magnetostriction coefficient λ m (Both can be pre-calibrated through independent hysteresis curve tests). In this way, formula (4) can link the microscopic, unknown force-magnetic coupling coefficient with the macroscopic, measurable magnetic parameters, so that the stress energy E in formula (1) σ It can be actually calculated, thus allowing for the further derivation of subsequent force-magnetic coupling models.

[0079] In some embodiments, in the force-magnetic coupling model, it is necessary to include the "mechanical part" (stress energy E in Formula 1). σThis is related to the "magnetic part," so it is necessary to calculate the increase in magnetic energy corresponding to the change in the magnetic state of the material caused by external stress.

[0080] As a feasible implementation method, according to electromagnetic theory, external stress Increased magnetic energy for: (Formula 5); In Formula 5, H represents the geomagnetic field strength, which is determined by the relationship between the magnetization, magnetic induction, and relative permeability of a ferromagnetic material. It can be seen that Formula 5 describes the change in magnetic induction from B when the material is under stress. T B changes under stress σ When the magnetic field does work or the magnetic energy stored in the system changes, the stress energy (mechanical input) is given by Equation 1 and the magnetic energy increment (magnetic response) by Equation 5. The two can then be equalized using the law of conservation of energy, thus establishing a quantitative relationship between stress and magnetic parameters.

[0081] As a feasible way to achieve this, and They can be represented as: (Formula 6); (Formula 7); In formulas 6 and 7, This represents the permeability of free space, while and They represent external stresses respectively. The relative permeability under stress and without stress. The purpose of these two formulas is to address the magnetic induction intensity B, which is difficult to measure directly in formula (5). σ and B T This is converted into the relative permeability μ, which can be determined through subsequent calibration experiments. σ and μ T Because magnetic flux density is greatly affected by environmental factors such as lift-off value and geomagnetic field fluctuations, while relative permeability is a magnetic property parameter of the material itself, it is more stable and has more physical significance. After introducing these two formulas, the entire force-magnetic coupling model shifts from "measuring the absolute value of an unstable magnetic field" to "calibrating the intrinsic permeability change of the material," providing a foundation for subsequent simultaneous solutions based on the law of conservation of energy (Formula 8) and the final derivation of the relationship between stress and relative permeability.

[0082] In some embodiments, according to the law of conservation of energy, external stress The increase in magnetic energy in ferromagnetic materials and Equal, that is: (Formula 8); Solving equations 1 and 5-8 simultaneously yields the following: (Formula 9); Substituting formula 4 into the equation, we get: (Formula 10); The relative permeability-stress relationship in the elastic stage is further obtained as follows: (Formula 11); Formula 11 is the first model, which establishes the relationship between the stress σ on the material and its relative permeability μ. σ This establishes a quantitative mathematical relationship between mechanical quantities (stress) and electromagnetic quantities (relative permeability), directly linking them. This means that as long as the inherent parameters of the material (initial relative permeability μ) can be determined experimentally... T , saturation magnetic induction intensity B m saturation magnetostriction coefficient λ m This formula can be used to determine the relative permeability μ based on the measured values. σ The stress value borne by the material is calculated in reverse. Although the magnetic sensor directly measures the magnetic induction intensity rather than the relative permeability in actual testing, Formula 11 provides a solid theoretical basis for establishing the empirical relationship between the "measured magnetic field signal and stress" through subsequent calibration experiments, making it possible for the force-magnetic coupling model to move from qualitative analysis to quantitative evaluation.

[0083] For example, in some embodiments, in order to obtain the initial magnetic properties of the test plate and the relevant mechanomagnetic model parameters, it is necessary to determine the hysteresis curve of the test plate and the saturation magnetic induction intensity of the test plate. Initial relative permeability With saturation magnetic induction coefficient .

[0084] The measurement procedure for hysteresis curves can be as follows: (1) The sample was made into a small cube of 5mm×5mm×1mm by wire cutting; (2) After sanding with sandpaper, perform mechanical polishing; (3) Clean it in an ultrasonic oscillator; (4) After washing and drying, use a high-precision analytical balance to accurately measure the sample mass; (5) Perform magnetization tests on the prepared test plate. For example, the test plate can be an L245 test sample.

[0085] S102. Obtain the actual stress and the actual magnetic induction intensity corresponding to the actual stress measured in the static calibration test, and determine the actual relative permeability based on the actual stress and the actual magnetic induction intensity corresponding to the actual stress measured in the static calibration test, and the first model.

[0086] Since the sampling frequencies and settings of the stress plate and magnetic sensor are corresponding, the stress data and magnetic induction intensity data measured in the static calibration test can be aligned. After data alignment, the measured data can be substituted into the relative permeability-stress relationship (Formula 11) in the elastic stage to calculate the actual relative permeability. .

[0087] In some embodiments, during static calibration testing, the magnetic sensor includes a first magnetic sensor and a second magnetic sensor; the first magnetic sensor is used to measure the magnetic induction intensity at its original setting position when the tensile testing machine stops stretching the test plate, and the second magnetic sensor is used to measure the magnetic induction intensity at various positions on the test plate when the tensile testing machine stops stretching the test plate; the static calibration test includes: before starting the tensile testing machine, recording the initial magnetic induction intensity of the test plate measured by the first magnetic sensor and the second magnetic sensor; after the tensile testing machine loads a preset load variable and stops loading, the strain gauge measures the stress, and the first magnetic sensor and the second magnetic sensor measure the magnetic induction intensity; after the strain gauge, the first magnetic sensor, and the second magnetic sensor have completed their measurements, the tensile testing machine loads a preset load variable until the load value of the tensile testing machine reaches the preset load value.

[0088] For example, the preset load variable can be 10 kN. Static calibration tests can be performed as follows: Figure 6 As shown, the initial magnetic induction intensity was measured before the stretching began. (Activate the magnetic sensor for 10-15 minutes to record the initial magnetic induction intensity) (including the geomagnetic field and environmental interference magnetic fields). The tensile testing machine starts from 0 load, and the load is increased to 10kN, 20kN, 30kN, ..., 80kN before being stopped and held at a constant pressure (following the cycle of "uniform loading - stopping and holding pressure - measurement - continuing loading"): Loading is stopped after the initial load reaches 10kN, and the load is allowed to stabilize (to avoid stress data fluctuations caused by tensile force rebound after stopping the load); after the measurement is completed, loading continues, successively reaching 20kN, 30kN...80kN (the specific upper limit is set according to the strength of the sample material, covering the three stages of elasticity, yielding, and uniform plastic deformation), repeating the "stop-measurement" operation every 10kN. During the measurement process, one magnetic sensor measures throughout, while another magnetic sensor dynamically scans the measurement area when the load stops. Simultaneously, strain gauges synchronously collect stress data to align stress with magnetic induction intensity. Finally, the actual stress and actual magnetic flux density measured in the static calibration test can be input into the first model to determine the subsequent force-magnetic coupling model.

[0089] A 10kN loading interval can obtain sufficiently dense data points in the elastic stage (ensuring the fitting accuracy of the "stress-relative permeability" correlation), and can also capture the changing trend of magnetic properties with stress state in the yield stage (stress changes gradually) and the uniform plastic deformation stage (stress rises slowly), avoiding the loss of key data due to excessively large sampling intervals.

[0090] In some embodiments, if a stress detection method with a wider measurement range is selected, the analysis of the tensile plastic deformation stage of steel can be performed.

[0091] S103. Obtain the initial magnetic induction intensity of the test plate and determine the target ratio between the actual magnetic induction intensity and the initial magnetic induction intensity.

[0092] Calculate the initial magnetic flux density B0 obtained from the air measurement, and divide the actual magnetic flux density B after alignment by B0 to obtain the target ratio B / B0.

[0093] S104. Establish a second model to characterize the fitting relationship between the actual relative permeability and the target ratio.

[0094] Using the target ratio B / B0 as the independent variable x and the actual relative permeability μσ as the dependent variable y, a polynomial regression method is used to establish a fitting relationship model between the two. The resulting second model expression is: (Formula 12) Wherein, a0-a4 are constant terms obtained by fitting, and this application does not limit them in the embodiments.

[0095] S105. Based on the second model and the first model, a third model is obtained to characterize the fitting relationship between the predicted stress and the target ratio.

[0096] The first model characterizes the relationship between relative permeability and stress, and the second model characterizes the relationship between relative permeability and the target ratio. By combining the first and second models and eliminating relative permeability, the relationship between stress and the target ratio can be obtained, resulting in the third model. Therefore, stress can be predicted based on the target ratio using the third model.

[0097] S106. Obtain the correspondence between the lift-off value and the magnetic field attenuation coefficient, and based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, modify the third model to obtain the force-magnetic coupling model.

[0098] In some embodiments, the third model is modified based on the correspondence between the lift-off value and the magnetic field attenuation coefficient to obtain a force-magnetic coupling model. Specifically, this can be achieved by: obtaining the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress; and modifying the third model based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, as well as the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress, to obtain a force-magnetic coupling model.

[0099] The data measured in the dynamic calibration test characterizes the actual magnetic working conditions of the pipeline. After correcting the third model based on the actual magnetic working conditions and the lift-off value, the force-magnetic coupling model can be obtained as follows: (Formula 13); Among them, in formula 13 This refers to the fitting function relationship of the second model mentioned above, which is the fourth-order polynomial established in Equation 12: .

[0100] The process of determining the predicted stress based on the force-magnetic coupling model can also be understood as follows: Figure 7 The process shown involves inputting the actual stress measured in the static calibration test into the first model, which yields a set of actual relative permeability corresponding to the actual stress. Then, a fitting relationship is established between the actual relative permeability and the target ratio. By inputting the actual magnetic flux density into the fitting relationship, the predicted relative magnetic flux density can be obtained. Finally, the predicted stress is obtained by using the predicted relative magnetic flux density to inversely deduce the stress.

[0101] According to such Figure 7 The process involves inputting relevant parameters into the force-magnetic coupling model. Once the relationship of the force-magnetic coupling model is determined, the predicted stress can be obtained by inputting the actual magnetic induction intensity, the initial measured magnetic induction intensity, and the lift-off value of the magnetic sensor from the surface of the test plate into the force-magnetic coupling model.

[0102] The influence of the initial magnetization state of the ferromagnetic material and the lift-off value of the magnetic sensor was considered. Based on the pipeline magnetization conditions and the lift-off value, a modified force-magnetic coupling model was obtained, which reduced the influence of different initial magnetization states, different measurement directions, and the geomagnetic field on the measured magnetic signal.

[0103] In some embodiments, the dynamic calibration test includes: before starting the tensile tester, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor, and the magnetic induction intensity when there is no stress; after the tensile tester is started, continuous loading is performed, the magnetic sensor continuously measures the magnetic induction intensity at the original setting position, and the strain gauge continuously measures the stress, until the load value of the tensile tester reaches the preset load value.

[0104] The specific process of dynamic calibration test can be as follows: Figure 8As shown: Before starting the stretching machine, the magnetic sensor should be turned on for a period of time for no-load measurement, and the initial magnetic induction intensity should be recorded. B 0. Before the tensile test begins, a set of stress-free measurements are taken as a control. The magnetic sensor only needs to be fixed for measurement; dynamic scanning is not required. The magnetic sensor lift-off value for fixed measurements is 10mm, and the magnetic sensor is aligned with the position where the strain gauge is attached to the test plate. The tensile machine is operated continuously without load until the plate breaks, and the magnetic sensor and strain gauge begin measurement simultaneously. The magnetic sensor measures the magnetic induction intensity throughout the test, and the acquisition frequency is the same as that of the strain gauge. After the dynamic calibration test is completed, the stress measured by the strain gauge during the tensile test is correlated with the magnetic field strength measured by the fluxgate sensor. This facilitates subsequent correction of the third model based on the measurement results of the dynamic calibration test to obtain the force-magnetic coupling model.

[0105] In some embodiments, to ensure the accuracy and reliability of the aforementioned force-magnetic coupling model in practical applications, this method also includes a crucial model verification step. This step involves designing and executing two different types of physical experiments—static and dynamic—to compare and analyze the theoretical predictions of the model with real-world measured data, thereby comprehensively verifying the model's stress prediction performance.

[0106] As a feasible implementation method, the method further includes: obtaining the actual stress measured in the static test and the actual magnetic induction intensity corresponding to the actual stress; and verifying the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the static test and the actual magnetic induction intensity corresponding to the actual stress.

[0107] In some embodiments, the static testing includes: before starting the tensile testing machine, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor; after the tensile testing machine loads a preset load variable and stops loading, the strain gauge measures the stress, and the magnetic sensor measures the magnetic induction intensity; after the strain gauge and magnetic sensor measurements are completed, the tensile testing machine loads the preset load variable until the load value of the tensile testing machine reaches the preset load value.

[0108] In one specific embodiment, a static testing test is first performed: before starting the tensile testing machine, the initial magnetic induction intensity of the test plate measured by the magnetic sensor is recorded; then the tensile testing machine is started, and stopped after each preset load variable is applied. At this time, the stress is measured by strain gauges, and the magnetic sensor simultaneously measures the magnetic induction intensity. After the data acquisition is completed, the next stage of loading is performed until the total load reaches the preset value. Next, the actual stress and corresponding magnetic induction intensity data obtained from these static tests are used to calculate the force-magnetic coupling model. The predicted stress output by the model is compared with the actual stress measured by the strain gauges to verify the accuracy of the model's stress prediction under static conditions.

[0109] In some embodiments, the method further includes: obtaining the actual stress measured in the dynamic testing test and the actual magnetic induction intensity corresponding to the actual stress; and verifying the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the dynamic testing test and the actual magnetic induction intensity corresponding to the actual stress.

[0110] The model's effectiveness is further verified through dynamic testing, with specific steps consistent with the aforementioned dynamic calibration test. This dual verification approach, combining static and dynamic methods, allows for the acquisition of high-precision baseline data through graded loading static tests, rigorously assessing the model's fundamental predictive capabilities. Furthermore, by reusing the validated dynamic calibration process, the standardization and consistency of dynamic prediction performance evaluation are ensured, thereby comprehensively and effectively evaluating the applicability and reliability of the force-magnetic coupling model under different operating conditions. In some embodiments, static testing is conducted after static calibration, dynamic calibration after static testing, and dynamic testing after dynamic calibration.

[0111] In some embodiments, during the dynamic tensile test (dynamic calibration test and dynamic detection test), the test plate is continuously loaded until it is uniformly deformed. The load is not interrupted during the tensile process, and stress measurement and magnetic field strength measurement are performed throughout the process. Dynamic calibration tests are performed according to different lift-off values.

[0112] Based on the above description, a complete example of a scheme including the experimental process and the verification process of the force-magnetic coupling model is as follows: 1. Sample size and pretreatment.

[0113] A rectangular specimen is flame-cut from a steel pipe, then cut using a saw, and finally flattened to form a plate-shaped specimen (test plate). Two specimen specifications are recommended: standard specimens and non-standard specimens (to increase the testing area). The specific dimensions of the standard specimen can be as follows: Figure 9 As shown (test area is 65mm × 38mm), the specific dimensions of the non-standard sample can be as follows: Figure 10 As shown (test area is 240mm × 40mm), the sample thickness is 5.5mm. After processing, the samples were annealed in a muffle furnace to relieve stress at 480℃ for 2 hours.

[0114] 2. Analysis of the static tensile test process and results.

[0115] Tensile tests were performed on L245 standard specimens according to the static calibration test procedure. The stress changes during the static calibration test were as follows: Figure 11 As shown, by Figure 11 It is evident that when the tensile testing machine stops, the tensile force will not stabilize at the expected value, but will instead rebound to a lower tensile force value compared to the expected value. The change in magnetic induction intensity during the static calibration test is as follows: Figure 12 As shown, comparison Figure 11 and Figure 12 It can be seen that the weak magnetic field detection signal can clearly reflect the stress change. After the tensile machine stops loading and the tensile force stabilizes, the magnetic induction intensity does not change significantly, but rather fluctuates slightly around a fixed value. A relatively stable interval between the magnetic signal and stress value is selected, and data alignment is performed using time as the reference point.

[0116] The static test used non-standard specimens and two stress measurement points. The measurement data from points X2 and Y2 are used here. Due to the influence of specimen size, the time for the non-standard specimen to stretch to the yield point and the time for plastic deformation differ from those of the standard specimen. However, when the tensile testing machine is stopped, the magnetic induction intensity and stress stabilize within a certain range. The stress change of the non-standard specimen, i.e., the stress change in the static test, is as follows: Figure 13 As shown, the magnetic flux density in the static test follows the same trend as that in the static calibration test, and the stress and magnetic flux density values ​​are aligned in the same way during the load-free zone.

[0117] 3. Dynamic tensile test process and result analysis.

[0118] In the dynamic tensile test, the tensile testing machine was never stopped. Strain gauges and magnetic sensors started recording simultaneously with the same sampling frequency, allowing for direct alignment of magnetic flux density and stress data. In the test result analysis, only the axial data of the specimen was analyzed. The trends of stress and magnetic flux density in the dynamic calibration test are as follows: Figure 14 As shown, the trends of stress and magnetic induction intensity in the dynamic testing experiment are as follows: Figure 15 As shown.

[0119] contrast Figure 14 and Figure 15 It can be observed that the axial magnetic induction intensity changes similarly during the tensile process for both types of specimens of different sizes. The magnetic induction intensity rises rapidly during the elastic tensile stage and then gradually levels off. Near the upper yield limit of the material, the slope becomes negative, showing a significant decreasing trend. In the dynamic calibration test, a standard specimen, smaller in size than the non-standard specimen, was used. Compared to the non-standard specimen, the standard specimen reached the upper yield limit in approximately 100 seconds of tension, indicating a shorter yielding stage. The change in magnetic induction intensity during the yielding stage was smaller for the standard specimen, showing a trend of first increasing and then decreasing.

[0120] 4. Determine the magnetic hysteresis characteristics of the sample.

[0121] Taking L245 steel, a commonly used material in oil and gas pipelines, as an example, to obtain the initial magnetic properties and related force-magnetic model parameters of L245 steel, it is necessary to determine its hysteresis characteristics. Before the hysteresis curve test, a new sample needs to be prepared. A sample is taken from the middle section of the standard specimen after static and dynamic tensile tests. The sampling area is similar to the sample... Figure 16 As shown, the sample was cut into small cubes of 5mm × 5mm × 1mm using wire cutting. After sanding and mechanical polishing, it was cleaned in an ultrasonic oscillator using alcohol as the cleaning agent. After cleaning and drying, it was ready for use. Then, the prepared L245 steel sample was subjected to a magnetization test. First, the sample mass was accurately measured using a high-precision analytical balance. Then, it was placed in the test kit for precise positioning to ensure that the sample received the strongest magnetic field signal.

[0122] Based on the hysteresis curve of the L245 steel sample, the parameters of the pipeline force-magnetic coupling model can be determined as shown in Table 1 below: Table 1 Parameters of the Force-Magnetic Coupling Model

[0123] 5. Pipeline stress calibration.

[0124] After aligning the stress data and magnetic flux density data obtained from the static calibration test, the stress values ​​are... Substituting into the relative permeability-stress relationship in the elastic stage, the relative permeability is calculated. .

[0125] Calculate the initial magnetic flux density B0 obtained from the air measurement, and divide the aligned magnetic flux density B by B0 to obtain the (B / B0) value. Fit the result to establish the relative permeability. The relationship between (B / B0) and (B0) is shown in Formula 14 below: (Formula 14).

[0126] relative permeability Ratio to target ( B / B The fitted curve between 0) can be as follows Figure 17 As shown.

[0127] After inputting the relevant parameters required for the force-magnetic coupling model and determining the fitting relationship, the predicted stress can be obtained simply by inputting the real-time magnetic induction intensity, the initial measured magnetic induction intensity, and the lift-off value of the sensor from the test surface.

[0128] Substituting the magnetic field strengths B and B0 obtained from the static test into Equation 12, we get... The predicted value, then Substituting the value into Formula 11, we obtain the predicted stress value. A schematic diagram comparing the predicted stress curve with the actual stress, plotted on the horizontal axis as magnetic induction intensity, can be shown as follows: Figure 18As shown.

[0129] During the stress calibration process, the stress calibration range was 10-220 MPa, but the stress prediction range could reach 0-350 MPa, covering the entire elastic stage of material tension, and the error was small, with an average error of 21 MPa and a maximum error of 50 MPa, indicating that the modified force-magnetic coupling model has good predictive performance. Figure 19 The comparison chart showing the predicted stress curve and the actual stress curve with time as the horizontal axis reveals that the stress curve predicted by the force-magnetic coupling model can basically reflect the actual stress magnitude and trend in real time.

[0130] The above-described method establishes and verifies a force-magnetic coupling model based on the law of energy conservation. In cases of stress damage caused by uniaxial tension in pipes, the stress magnitude at the pipe measurement point can be obtained based on the real-time magnetic field strength through calibration and hysteresis curve measurement. This enables quantitative analysis and evaluation of stress concentration points in pipelines, and has broad practical application significance. For example, by importing the derived force-magnetic coupling model into the program of a buried pipeline stress quantitative detection device, the multidimensional magnetic field values ​​obtained by the multiple magnetic sensors equipped in the device can be used to analyze the stress magnitude at the pipe measurement point in real time.

[0131] The above experimental procedure can accurately and effectively obtain the correspondence between magnetic induction intensity and stress, thereby exploring the variation law of magnetic induction intensity in the tensile elastic-plastic stage of the material, and providing strong assistance for the quantitative evaluation of the stress state of steel components in electromagnetic nondestructive testing.

[0132] Figure 5 The technical solution presented offers at least the following benefits: First, by establishing the first model, it provides a basis for the correlation between stress and magnetic properties. Second, by establishing the second model, it correlates theoretical relationships with experimental data and eliminates the influence of initial magnetic induction intensity on the correlation accuracy. The third model, derived from the first and second models, characterizes the fitting relationship between the predicted stress and the target ratio. Stress can then be predicted using easily measurable magnetic induction intensity and initial magnetic induction intensity, eliminating the need for complex intermediate calculations of magnetic permeability, thus improving stress calculation efficiency. Furthermore, by establishing the correspondence between lift-off values ​​and magnetic field attenuation coefficients, the third model is corrected. This corrected force-magnetic coupling model eliminates the interference of lift-off values, improving the accuracy and precision of pipeline stress detection and providing a reference for the quantitative assessment of pipeline stress concentration areas.

[0133] The foregoing primarily describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the aforementioned functions, it includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0134] This application also provides a device for determining a force-magnetic coupling model, used to execute the method for determining a force-magnetic coupling model shown in the above-described method embodiments. Figure 20 As shown, the device 200 for determining the force-magnetic coupling model includes a processing module 201 and an acquisition module 202.

[0135] The system includes the following components: Processing module 201 is used to determine a first model, which characterizes the theoretical relationship between stress and relative permeability of the test plate; Acquisition module 202 is used to acquire the actual stress measured in the static calibration test and the corresponding actual magnetic flux density; Processing module 201 is also used to determine the actual relative permeability based on the corresponding actual stress and actual magnetic flux density, and the first model; Acquisition module 202 is also used to acquire the initial magnetic flux density of the test plate; Processing module 201 is also used to determine the target ratio between the actual magnetic flux density and the initial magnetic flux density; Processing module 201 is also used to establish a second model to characterize the fitting relationship between the actual relative permeability and the target ratio; Processing module 201 is also used to obtain a third model to characterize the fitting relationship between the predicted stress and the target ratio based on the second model and the first model; Acquisition module 202 is also used to acquire the correspondence between the lift-off value and the magnetic field attenuation coefficient. The processing module 201 is also used to correct the third model based on the correspondence between the lift-off value and the magnetic field attenuation coefficient to obtain the force-magnetic coupling model.

[0136] In some embodiments, the processing module 201 is specifically used to: determine the hysteresis curve of the test plate; determine the saturation magnetic induction intensity, initial relative permeability and saturation magnetic induction coefficient of the test plate based on the hysteresis curve; and determine the first model based on the saturation magnetic induction intensity, initial relative permeability and saturation magnetic induction coefficient of the test plate.

[0137] In some embodiments, a strain gauge is disposed on one side of the test plate and a magnetic sensor is disposed on the other side. The placement positions of the strain gauge and the magnetic sensor correspond. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. During static calibration testing, the magnetic sensor includes a first magnetic sensor and a second magnetic sensor. The first magnetic sensor is used to measure the magnetic induction intensity at its original placement position when the tensile machine stops stretching the test plate, and the second magnetic sensor is used to measure the magnetic induction intensity at various positions on the test plate when the tensile machine stops stretching the test plate. The static calibration test includes: before the tensile machine is started, recording the initial magnetic induction intensity of the test plate measured by the first magnetic sensor and the second magnetic sensor; after the tensile machine loads a preset load variable and stops loading, the strain gauge measures the stress, and the first and second magnetic sensors measure the magnetic induction intensity; after the strain gauge, the first magnetic sensor, and the second magnetic sensor have completed their measurements, the tensile machine loads the preset load variable until the load value of the tensile machine reaches the preset load value.

[0138] In some embodiments, the acquisition module 202 is further configured to acquire the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress; the processing module 201 is further configured to modify the third model based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, as well as the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress, to obtain the force-magnetic coupling model.

[0139] In some embodiments, a strain gauge is provided on one side of the test plate and a magnetic sensor is provided on the other side. The positions of the strain gauge and the magnetic sensor correspond. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. The dynamic calibration test includes: before the tensile machine is started, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor and the magnetic induction intensity when there is no stress; after the tensile machine is started, continuous loading is carried out, the magnetic sensor continuously measures the magnetic induction intensity at the original setting position, and the strain gauge continuously measures the stress, until the load value of the tensile machine reaches the preset load value.

[0140] In some embodiments, the acquisition module 202 is further configured to acquire the actual stress measured in the static test and the actual magnetic flux density corresponding to the actual stress; the processing module 201 is further configured to verify the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the static test and the actual magnetic flux density corresponding to the actual stress; and / or, the acquisition module 202 is further configured to acquire the actual stress measured in the dynamic test and the actual magnetic flux density corresponding to the actual stress; the processing module 201 is further configured to verify the stress prediction effect of the force-magnetic coupling model based on the actual stress measured in the dynamic test and the actual magnetic flux density corresponding to the actual stress.

[0141] In some embodiments, the static testing includes: before starting the tensile testing machine, recording the initial magnetic induction intensity of the test plate measured by the magnetic sensor; after the tensile testing machine loads a preset load variable and then stops loading, the strain gauge measures the stress, and the magnetic sensor measures the magnetic induction intensity; after the strain gauge and magnetic sensor measurements are completed, the tensile testing machine loads a preset load variable until the load value of the tensile testing machine reaches the preset load value; the steps of the dynamic testing are the same as those of the dynamic calibration testing.

[0142] It should be noted that the above Figure 20 The module division is illustrative and represents only one logical functional division; in actual implementation, other division methods are possible. For example, two or more functions can be integrated into a single processing module 201. The integrated modules described above can be implemented in hardware or as software functional modules.

[0143] Another embodiment of this application provides an electronic device, including: one or more processors; one or more memories; wherein the one or more memories are used to store computer program code, the computer program code including computer instructions, and when the one or more processors execute the computer instructions, the electronic device executes any of the methods for determining the force-magnetic coupling model provided in the above embodiments.

[0144] Another embodiment of this application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed on a computer, cause the computer to perform any of the force-magnetic coupling model determination methods provided in the above embodiments.

[0145] Another embodiment of this application provides a computer program product including computer instructions that, when executed on an electronic device, cause the electronic device to perform any of the force-magnetic coupling model determination methods provided in the above embodiments.

[0146] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining a force-magnetic coupling model, characterized in that, include: A first model is established to characterize the theoretical relationship between stress and relative permeability of the test plate. The actual stress and the actual magnetic flux density corresponding to the actual stress are obtained in the static calibration test, and the actual relative permeability is determined based on the actual stress and the actual magnetic flux density corresponding to the actual stress, and the first model. Obtain the initial magnetic induction intensity of the test plate and determine the target ratio between the actual magnetic induction intensity and the initial magnetic induction intensity; A second model is established to characterize the fitting relationship between the actual relative permeability and the target ratio; Based on the first model and the second model, a third model is obtained to characterize the fitting relationship between the predicted stress and the target ratio; The correspondence between the lift-off value and the magnetic field attenuation coefficient is obtained, and the third model is modified based on the correspondence between the lift-off value and the magnetic field attenuation coefficient to obtain the force-magnetic coupling model.

2. The method according to claim 1, characterized in that, The determination of the first model includes: Determine the hysteresis curve of the test plate; Based on the hysteresis curve, the saturation magnetic induction intensity, initial relative permeability, and saturation magnetic induction coefficient of the test plate are determined. The first model is determined based on the saturation magnetic induction intensity, initial relative permeability, and saturation magnetic induction coefficient of the test plate.

3. The method according to claim 1, characterized in that, On one side of the test plate, a strain gauge is provided, and on the other side, a magnetic sensor is provided. The positions of the strain gauge and the magnetic sensor are corresponding. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. During the static calibration test, the magnetic sensor includes a first magnetic sensor and a second magnetic sensor; the first magnetic sensor is used to measure the magnetic induction intensity at the original setting position of the first magnetic sensor when the stretching machine stops stretching the test plate, and the second magnetic sensor is used to measure the magnetic induction intensity at various positions of the test plate when the stretching machine stops stretching the test plate. The static calibration test includes: Before starting the stretching machine, record the initial magnetic induction intensity of the test plate as measured by the first magnetic sensor and the second magnetic sensor; The tensile machine stops loading after loading a preset load variable, the strain gauge measures the stress, and the first magnetic sensor and the second magnetic sensor measure the magnetic induction intensity. After the strain gauge, the first magnetic sensor, and the second magnetic sensor have completed their measurements, the tensile machine applies a preset load variable until the load value of the tensile machine reaches the preset load value.

4. The method according to claim 1, characterized in that, The third model is modified based on the correspondence between the lift-off value and the magnetic field attenuation coefficient to obtain a force-magnetic coupling model, including: Obtain the actual stress and the corresponding actual magnetic induction intensity measured in the dynamic calibration test; Based on the correspondence between the lift-off value and the magnetic field attenuation coefficient, as well as the actual stress measured in the dynamic calibration test and the actual magnetic induction intensity corresponding to the actual stress, the third model is modified to obtain the force-magnetic coupling model.

5. The method according to claim 4, characterized in that, On one side of the test plate, a strain gauge is provided, and on the other side, a magnetic sensor is provided. The positions of the strain gauge and the magnetic sensor are corresponding. The strain gauge is used to detect the stress of the test plate, and the magnetic sensor is used to detect the magnetic induction intensity of the test plate. The dynamic calibration test includes: Before starting the stretching machine, record the initial magnetic induction intensity of the test plate measured by the magnetic sensor, as well as the magnetic induction intensity when there is no stress. After the tensile machine is started, it continuously loads the load. The magnetic sensor continuously measures the magnetic induction intensity at the original set position, and the strain gauge continuously measures the stress until the load value of the tensile machine reaches the preset load value.

6. The method according to claim 5, characterized in that, The method further includes: Obtain the actual stress and the corresponding actual magnetic induction intensity measured in the static test; Based on the actual stress measured in the static test and the actual magnetic induction intensity corresponding to the actual stress, the stress prediction effect of the force-magnetic coupling model is verified. And / or, Obtain the actual stress and the corresponding actual magnetic induction intensity measured in the dynamic testing experiment; Based on the actual stress measured in the dynamic testing experiment and the actual magnetic induction intensity corresponding to the actual stress, the stress prediction effect of the force-magnetic coupling model is verified.

7. The method according to claim 6, characterized in that, The static testing includes: Before starting the stretching machine, record the initial magnetic induction intensity of the test plate as measured by the magnetic sensor; The tensile machine stops loading after loading a preset load variable, the strain gauge measures the stress, and the magnetic sensor measures the magnetic induction intensity. After the strain gauge and the magnetic sensor complete the measurement, the tensile machine applies a preset load variable until the load value of the tensile machine reaches the preset load value; The steps of the dynamic detection test are the same as those of the dynamic calibration test.

8. A device for determining a force-magnetic coupling model, characterized in that, include: The processing module is used to determine the first model for characterizing the theoretical relationship between stress and relative permeability of the test plate. The acquisition module is used to acquire the actual stress measured in the static calibration test and the actual magnetic induction intensity corresponding to the actual stress. The processing module is also used to determine the actual relative permeability based on the corresponding actual stress and actual magnetic induction intensity, as well as the first model. The acquisition module is also used to acquire the initial magnetic induction intensity of the test plate. The processing module is further configured to determine a target ratio between the actual magnetic induction intensity and the initial magnetic induction intensity; The processing module is also used to establish a second model to characterize the fitting relationship between the actual relative permeability and the target ratio; The processing module is further configured to obtain a third model based on the first model and the second model to characterize the fitting relationship between the predicted stress and the target ratio. The acquisition module is also used to acquire the correspondence between the lift-off value and the magnetic field attenuation coefficient; The processing module is also used to modify the third model based on the correspondence between the lift-off value and the magnetic field attenuation coefficient to obtain a force-magnetic coupling model.

9. An electronic device, characterized in that, include: One or more processors; One or more memory units; Wherein, the one or more memories are used to store computer program code, the computer program code including computer instructions, and when the one or more processors execute the computer instructions, the electronic device executes the method for determining the force-magnetic coupling model according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when executed on a computer, cause the computer to perform the method for determining the force-magnetic coupling model according to any one of claims 1-7.

Images