Rotary probe for residual stress tensor detection and detection method

Abstract

The invention discloses a rotary probe for residual stress tensor detection and a detection method. The rotary probe comprises a main excitation module, a receiving module, a rotary mechanism and a shell, the main excitation module, the receiving module and the rotating mechanism are all arranged in the shell, the main excitation module is arranged in the shell in a U shape, the rotating mechanism and the receiving module are arranged on the inner side of the U shape of the main excitation module, and the rotating mechanism is connected with the receiving module and used for driving the receiving module to rotate. Compared with a traditional stress tensor electromagnetic detection device, the overall movement of the probe is avoided while the size of the probe is not changed, and the spatial resolution and the positioning precision are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of residual stress tensor detection, and in particular relates to a rotating probe and a detection method for residual stress tensor detection. Background Art

[0002] The reactor pressure vessel (RPV) of a nuclear power plant is the core pressure-bearing equipment of a nuclear reactor, and its structural integrity is of great significance to the safe operation of a nuclear power plant. However, due to the thermomechanical loads during manufacturing, welding, and long-term operation, a certain amount of stress, namely residual stress, often remains inside the pressure vessel. This stress may cause local deformation, crack propagation, and even fracture failure of the material. When superimposed with external stress, it further aggravates the risk of fatigue damage and stress corrosion, seriously threatening the structural integrity and operational safety of the equipment. It is particularly noteworthy that the directionality of residual stress has a decisive influence on the crack propagation path, material bearing capacity, and corrosion tendency. For example, cracks perpendicular to the direction of the principal stress are most likely to propagate, which significantly affects the structural reliability. Therefore, accurately measuring the magnitude and direction of residual stress in pressure vessels is crucial for safety assessment and the formulation of maintenance plans.

[0003] Existing detection technologies such as X-ray diffraction, neutron diffraction, ultrasonic method and blind hole method have made some progress in residual stress measurement, but there are problems such as low spatial resolution, expensive equipment, complex operation, lossy sampling, poor online detection capability, and insufficient ability to analyze stress direction in complex structures. It is urgent to develop more efficient and accurate detection methods. Electromagnetic nondestructive testing is a promising stress detection method for ferromagnetic materials. Based on the mechanism of interaction between electromagnetic field and internal microstructure of materials, it can detect defects, stress distribution or structural changes on the surface or near the surface of materials. It has the advantages of nondestructive, non-contact, real-time and fast.

[0004] The electromagnetic devices currently used for stress tensor directional detection can be roughly divided into two categories: one is to use traditional U-shaped magnetic yoke excitation, rotate the probe manually or by a mechanical arm, or use a displacement platform to rotate the material to achieve circumferential multi-angle detection. However, this method has problems such as poor positioning accuracy, insufficient stability, and complex and time-consuming operation, which makes it difficult to meet the needs of fast and accurate detection and evaluation on the production line. The second is to use orthogonal magnetic yokes or multi-pole probes, as published in patent number CN 114839258 B, to achieve spatial excitation by adjusting the excitation signals of different channels to achieve magnetic field angle changes. The disadvantage is that the probe is too large to fit into a small space, the detection space resolution is low, and more than two excitation signals need to be precisely adjusted, resulting in complex processing circuits. Summary of the invention

[0005] The object of the present invention is to provide a rotating probe and a detection method for residual stress tensor detection to solve the above-mentioned problem.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A rotating probe for residual stress tensor detection includes a main excitation module, a receiving module, a rotating mechanism and a shell; the main excitation module, the receiving module and the rotating mechanism are all arranged in the shell, the main excitation module is arranged in a U shape inside the shell, the rotating mechanism and the receiving module are arranged on the U-shaped inner side of the main excitation module, and the rotating mechanism is connected to the receiving module to drive the receiving module to rotate.

[0007] Furthermore, the main excitation module includes a U-shaped yoke, two coil frames and an excitation coil. The coil frames are mounted on the yoke arms on both sides of the U-shaped yoke. The excitation coil is wound turn by turn on the two coil frames in the same direction. Raised thin plate structures are provided at both ends of the coil frames to isolate the winding layers and form a uniform and continuous magnetic circuit inside the U-shaped yoke and the material under test.

[0008] Furthermore, the U-shaped magnetic yoke is formed by stacking multiple layers of oriented silicon steel sheets, and the magnetic pole cross section is rectangular; the coil frame is made of nylon material; and the excitation coil is made of enameled wire.

[0009] Furthermore, the receiving module includes a magnetic head, a magnetic sensor, a PCB board and a magnetic head package. The magnetic head and the magnetic sensor are fixed on the circular PCB board by welding; the magnetic head package is cylindrical, and its inner diameter matches the diameter of the PCB board. After the magnetic head and the magnetic sensor are installed, epoxy resin is poured into the interior of the magnetic head package.

[0010] Furthermore, the magnetic head includes a first special-shaped sharp claw yoke, a second special-shaped sharp claw yoke, an aluminum alloy shielding cover, an isolation plate and a glass clip. The first special-shaped sharp claw yoke and the second special-shaped sharp claw yoke are symmetrically placed side by side. Glass clips are arranged inside the first special-shaped sharp claw yoke and the second special-shaped sharp claw yoke to produce a working gap. An isolation plate is arranged between the first special-shaped sharp claw yoke and the second special-shaped sharp claw yoke, and the outside of the magnetic head is covered with an aluminum alloy shielding cover.

[0011] Furthermore, a receiving coil is arranged on the first special-shaped sharp claw yoke for receiving the voltage signal of magnetic Barkhausen noise and incremental magnetic permeability; a high-frequency excitation coil is arranged on the second special-shaped sharp claw yoke for generating a high-frequency alternating magnetic field; four pins of the receiving coil and the high-frequency excitation coil are welded on the PCB board for signal transmission.

[0012] Furthermore, the magnetic sensor is a Hall sensor; the first special-shaped sharp claw yoke and the second special-shaped sharp claw yoke are formed by stacking multiple layers of oriented silicon steel sheets.

[0013] Furthermore, the rotating mechanism includes a gear bearing, a driving gear and a driven gear, the gear bearing is fixed on the upper shell; the driving gear is installed on the gear bearing, there is a rectangular opening on the surface of the shell, and the driving gear is arranged in the rectangular hole; the driven gear is connected to the driving gear through gear meshing, and a cylindrical thin-walled structure is arranged above the driven gear, its top end is in contact with the shell, and a protrusion is arranged on the bottom to be clamped on the upper end of the head package. Furthermore, the shell includes an upper shell, a lower shell and an aviation plug. The upper shell and the lower shell are connected by a snap-on structure. Openings are provided at the bottom of the upper shell and the lower shell, which are rectangular openings for the two poles of the U-shaped magnetic yoke and a circular opening for the receiving module. The magnetic poles of the U-shaped magnetic yoke and the magnetic head package of the receiving module extend out of the bottom opening of the shell. The aviation plug is arranged on the surface of the shell, and the excitation power supply, ground wire, head signal line and magnetic sensor signal line are respectively connected through the aviation plug.

[0014] A detection method of a rotating probe for residual stress tensor detection comprises the following steps: First, polish the surface of the sample to be tested, place the probe at the target detection position of the material to be tested, ensure that the bottom of the probe is in close contact with the sample surface, and define the angle of the receiving module at this time as the reference angle; The excitation system is turned on, and the signal generator generates low-frequency sinusoidal excitation, which is applied to the excitation coil of the U-shaped magnetic yoke through the power amplifier; the magnetic head is sequentially connected to the bandpass filter and signal amplifier in the signal processing system; the magnetic sensor signal is connected to the low-pass filter and differential amplifier to obtain the magnetic Barkhausen noise and tangential magnetic field signal, and the signal is transmitted to the host computer for storage; Change the excitation signal. One channel of the signal generator outputs low-frequency sinusoidal excitation, which is applied to the excitation coil through the power amplifier. The other channel outputs high-frequency sinusoidal excitation, and generates a high-frequency excitation current with constant amplitude through the constant current source module, which is applied to the high-frequency excitation module of the magnetic head. At the same time, the high-frequency signal is applied to the reference end of the phase-locked amplifier as the reference signal for orthogonal demodulation. After the magnetic head signal is connected to the phase-locked amplifier for processing, the incremental magnetic permeability signal is obtained and the signal is transmitted to the host computer. In order to eliminate the influence of magnetic field directionality, low-frequency excitation with different amplitude-frequency parameters is used for multiple measurements to obtain electromagnetic feedback signals under different excitation voltages. At the same time, repeated measurements are performed for the acquisition process of the above signals, and the collected data are averaged. Use the gear rotation mechanism to rotate the receiving module at a specified step length to collect electromagnetic signals at different angles at the same point until a full cycle of signal detection is completed; After the detection task is completed, the collected signals are analyzed and processed, the data of different excitation parameters are compared and analyzed, and feature value extraction, correlation analysis and data dimension reduction are performed. In order to eliminate the influence of the directionality of the external magnetic field on the measurement results, the angle compensation is performed by integrating the data of different excitation parameters, and then the polar coordinate graph that changes with the angle is drawn. The principal stress direction is finally determined by comprehensive analysis of the processed data, and the magnitude of the principal stress is finally calculated by combining the pre-established calibration curve.

[0015] Compared with the prior art, the present invention has the following technical effects: The present invention provides a high-resolution rotating probe device for residual stress tensor detection, which adopts a traditional U-shaped double-pole magnetic yoke for excitation, and a receiving module adopts a structure of a special-shaped sharp claw magnetic yoke plus a coil winding, and is wrapped with a shielding cover on the outside. The working gap at the sharp claw of the magnetic yoke is isolated by a hard glass clip, and the width is only a few microns. The overall detection space is a rectangular area, and the lateral spatial resolution is greatly improved. With the gear transmission rotating mechanism on the shell, it can be achieved that the signal at any circumferential angle can be measured only by rotating the magnetic head and magnetic sensor of the receiving module under the premise that the main excitation magnetic yoke is fixed. The probe device can realize time-sharing measurement of three electromagnetic non-destructive testing methods including magnetic Barkhausen noise (MBN), incremental magnetic permeability (MIP) and tangential magnetic field harmonic analysis (HA). After subsequent signal processing and eigenvalue extraction, combined with the existing calibration model, the main stress size and direction of the residual stress can be obtained. Compared with the traditional stress tensor electromagnetic detection device, the probe avoids the overall movement of the probe while keeping the volume unchanged, and improves the spatial resolution and positioning accuracy.

[0016] The receiving module adopts a structure of special-shaped sharp claw yoke and coil winding, and is covered with a shielding cover on the outside, which effectively prevents environmental noise interference and greatly improves the stability of the receiving signal; The working gap between the special-shaped sharp claws and the magnetic yoke is isolated by the glass clip. Compared with the combination of the traditional hollow coil and the ferrite core with a resolution of centimeters, the probe designed by the present invention can reach the order of tens to hundreds of microns, and the spatial resolution is greatly improved. Different from the circular detection area of ​​the traditional coil, the detection range of the probe designed in the present invention is a rectangular area, the length of which is the thickness of the special-shaped sharp claw yoke, and the width is the width of the clip. Combined with the matching gear transmission rotating mechanism, the detection signals in different directions can be easily distinguished by rotating the magnetic head receiving module under the premise that the U-shaped yoke 1 is fixed, thereby realizing the detection of the directionality of the residual stress tensor; The probe designed in the present invention realizes the integrated design of multiple electromagnetic nondestructive testing methods. Without replacing the sensor, it can realize time-sharing or simultaneous measurement of three electromagnetic nondestructive testing methods including magnetic Barkhausen noise (MBN), incremental magnetic permeability (MIP) and tangential magnetic field harmonic analysis (HA). It has rich measurement signals, small size and simple structure, which can greatly improve the accuracy and efficiency of residual stress tensor detection, and greatly expand the application scenarios. For incremental magnetic permeability (MIP) testing in electromagnetic nondestructive testing, the superposition direction of low-frequency and high-frequency magnetic fields in conventional MIP testing methods is relatively fixed, and there are only two types: one is to wind the high-frequency and low-frequency excitation coils on the same U-shaped yoke, that is, the low-frequency and high-frequency magnetic field directions are parallel; the other is to wind the low-frequency coil on the U-shaped yoke, and place a ferrite coil with high-frequency excitation between the two poles, that is, the high-frequency and low-frequency magnetic field directions are perpendicular. The probe designed by the present invention can achieve high- and low-frequency magnetization superposition directions at different angles by fixing the low-frequency U-shaped yoke 1 and rotating the high-frequency excitation special-shaped yoke 42, thereby creating more detection combinations and studying the characterization law of residual stress by the MIP detection method under different superposition directions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 : Schematic diagram of the internal structure of the rotating probe.

[0018] Figure 2 : Overall schematic diagram of the rotating probe.

[0019] Figure 3 : Overall schematic diagram of the receiving module.

[0020] Figure 4 : Schematic diagram of the internal structure of the magnetic head.

[0021] Figure 5 : Schematic diagram of the high-resolution rotation detection system.

[0022] in: 1 - U-shaped magnetic yoke; 2 - coil frame; 3 - excitation coil; 4 - magnetic head; 5 - magnetic sensor; 6 - gear bearing; 7 - driving gear; 8 - driven gear; 9 - magnetic head package; 10 - lower shell; 11 - aviation plug; 12 - upper shell; 13 - PCB board; 41 - magnetic head shield; 42 - first special-shaped sharp claw yoke; 43 - second special-shaped sharp claw yoke; 44 - isolation plate; 45 - clip; 46 - receiving coil; 47 - high-frequency excitation coil. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings: See also Figures 1 to 4 The present invention is assembled from four parts: a main excitation module, a receiving module, a rotating mechanism and a shell. The specific assembly relationship is described below.

[0024] The main excitation module includes a U-shaped yoke 1, two coil skeletons 2 and an excitation coil 3, wherein the U-shaped yoke 1 is formed by stacking multiple layers of oriented silicon steel sheets, and the magnetic pole cross-section is rectangular; the coil skeleton 2 is made of nylon material and is tightly fitted on the yoke arms on both sides of the U-shaped yoke 1, and a raised thin plate structure is provided at both ends of the skeleton to isolate the winding layer, so as to facilitate the multi-layer winding of the excitation coil 3; the excitation coil 3 is made of enameled wire with a wire diameter of 0.3mm, and is wound turn by turn on the two coil skeletons 2 in the same direction, so as to ensure that a uniform and continuous magnetic circuit can be formed inside the U-shaped yoke 1 and the material under test after power is turned on.

[0025] The receiving module includes a magnetic head 4, a magnetic sensor 5, a PCB board 13 and a magnetic head package 9, wherein the magnetic sensor 5 is a Hall sensor; the magnetic head 4 and the magnetic sensor 5 are fixed on the customized circular PCB board 13 by welding to realize the power supply, signal transmission and fixing functions; the magnetic head package 9 is made of resin material using a 3D printing process, and is cylindrical as a whole, with an inner diameter matching the diameter of the PCB board 13, and an outer diameter matching the outer shell 10 and the support frame 12 to ensure precise assembly. After the magnetic head 4 and the magnetic sensor 5 are installed, epoxy resin is poured into the interior of the magnetic head package 9 to improve the structural stability and enhance the anti-vibration performance to avoid the influence of external interference on signal reception.

[0026] During the assembly process, it is necessary to ensure that the bottom of the two poles of the U-shaped yoke 1, the bottom of the head package 9, the bottom of the magnetic sensor 5 and the tangent of the arc surface of the head shielding cover 41 are kept on the same horizontal plane, so as to achieve a close fit between the excitation module and the receiving module and the surface of the material being tested, effectively reduce magnetic flux leakage, and maximize the reception of feedback signals.

[0027] Next, the internal structure of the magnetic head 4 is described in detail. Figure 3 and Figure 4 As shown, its core component is a structure of two special-shaped sharp claw yokes and coil winding, which can realize the two functions of high-frequency excitation and reception. The first special-shaped sharp claw yoke 42 and the second special-shaped sharp claw yoke 43 are placed symmetrically side by side, and are composed of multiple layers of oriented silicon steel sheets stacked together. The top of the yoke is wound with a self-adhesive coil, with a DC resistance of 230Ω, and a compact and reliable structure. The working gap between the sharp claws of the yoke is isolated by a hard glass clip 45, and its width can be customized according to the specific requirements of the detection resolution, ranging from a few microns to more than ten microns. And in order to prevent mutual electromagnetic interference between the yokes, an isolation plate 44 is set between the two yokes, which is also made of hard glass, with high insulation and good mechanical stability. The outside of the magnetic head 4 is covered with an aluminum alloy shielding cover 41, which can effectively shield the external interference magnetic field, thereby significantly improving the signal-to-noise ratio of the received signal.

[0028] There is a clear division of labor between the two yokes, wherein the first special-shaped sharp claw yoke 42 and the receiving coil 46 constitute the signal receiving part, which can be used to receive the voltage signals of MBN and MIP; the first special-shaped sharp claw yoke 43 and the high-frequency excitation coil 47 serve as the high-frequency excitation part of the MIP detection method, which is used to generate a high-frequency alternating magnetic field. In order to ensure the stability and vibration resistance of the overall structure, the special-shaped yoke coil assembly and the isolation plate 44, the clip 45 and other components are all fixed with epoxy resin, and insulation protection is provided at the same time. After the epoxy resin is cured, only the four pins of the receiving coil 46 and the high-frequency excitation coil 47 are led out from the top of the magnetic head 4 and welded on the PCB board 13 for signal transmission. This design not only effectively enhances the anti-interference ability of the magnetic head, but also ensures the signal acquisition accuracy and the overall reliability of the device.

[0029] Next, the mechanical rotating mechanism is described, which is composed of three parts: a gear bearing 6, a driving gear 7 and a driven gear 8. The gear bearing 6 is fixed in a groove inside the upper housing 12 to support and limit the rotational axial position of the gear; the driving gear 7 is made of 316L stainless steel using a 3D printing process and is installed on the gear bearing 6 as a transmission source. The outer surface of the upper housing 12 has a rectangular opening, and a part of the driving gear 7 is exposed outside the housing, which is convenient for the operator to rotate and adjust the angle of the magnetic head 4 during the residual stress detection process; the driven gear 8 is also made by 3D printing. The driven gear 8 is connected to the driving gear 7 through gear meshing. In addition to the gear tooth surface structure, a cylindrical thin-walled structure is arranged above the driven gear 8, and its top end contacts the internal brackets of the housing 10 and 12, so as to provide a stable fixation when the overall structure is assembled and enhance the stability of the structure; a protrusion is arranged at the bottom, which can just clamp the upper end of the magnetic head package 9. The two form a matching relationship through this protrusion structure, thereby effectively fixing the PCB board 13 inside the magnetic head package 9 and the magnetic head 4 and magnetic sensor 5 installed thereon, ensuring that no displacement or looseness occurs during the assembly process. After the assembly is completed, glue is used to bond the driven gear 8 and the magnetic head package 9 so that they can rotate coaxially as a whole.

[0030] The rotating mechanism designed in the present invention is controlled manually, and the rotation step can be improved according to the actual needs of the master / driven gear size and the number of teeth. Under complex working conditions, a stepping reduction motor can be added to perform precise remote electronic control of the rotation angle to meet higher precision working requirements.

[0031] Finally, there is the shell and interface part, which consists of three parts: the upper shell 12, the lower shell 10 and the aviation plug 11. The upper and lower shells are made of resin material 3D printing, and can be firmly docked through the snap-on structure to form an overall stable structure. The surface of the upper shell 12 is designed with a rectangular opening and a vertical indicator line for the driving gear 7, which is convenient for the operator to accurately judge the rotation angle of the receiving module during the detection process and ensure the precise alignment of the bottom receiving module during the entire rotation process. In addition, the upper and lower shells adopt a completely symmetrical design to ensure the uniformity of the shell structure and the assembly accuracy.

[0032] The bottom of the upper shell 12 and the lower shell 10 are designed with specific openings: including rectangular openings at the two poles of the U-shaped yoke 1 and a circular opening of the receiving module, to ensure that the yoke and the receiving module can maintain a stable and tight fit when in contact with the material to be tested. The inside of the shell is provided with a limit bracket for fixing the U-shaped yoke 1, the gear bearing 6, the driven gear 8 and the head package 9, etc., which is used to accurately position the yoke, the rotating mechanism and the receiving module, to ensure that the bottom of the yoke is completely aligned with the bottom of the receiving module and is in a horizontal state, thereby ensuring stable reception of the signal during the detection process. The poles of the U-shaped yoke 1 and the head package 9 of the receiving module are designed to extend out of the bottom opening of the shell by about 2 mm to ensure that they can fully contact the material to be tested, to avoid the shell size deviation caused by the printing accuracy error from interfering with the detection results.

[0033] The interface part adopts GX16-9 core aviation plug, through which the excitation power supply, ground wire, magnetic head signal wire and magnetic sensor signal wire are connected respectively. Each signal line is connected to the external signal generator and signal processing system through different wiring terminals of the aviation plug, so as to realize stable communication and data transmission between the probe and the external system, and ensure the integrated design of the integrated probe.

[0034] The present invention provides a high-resolution rotating probe, the overall structure of which includes key components such as a probe housing, an aviation plug, a U-shaped magnetic yoke, an excitation coil, an active / driven gear, a magnetic head, and a magnetic sensor. Compared with existing stress tensor detection equipment, the probe designed by the present invention is more compact in size and can adapt to a variety of complex detection environments. It is also equipped with a magnetic head device with high spatial resolution. Traditional ferrite coils can usually only receive signals in a circular detection area, while the magnetic head designed by the present invention can accurately receive signals in a rectangular area on the surface of the material, thereby significantly improving the spatial resolution and signal sensitivity of the detection area.

[0035] The probe design introduces a gear rotation mechanism, which creatively realizes the function of rotating only the receiving module through a mechanical transmission structure, thus avoiding the unnecessary complexity and positioning errors caused by the traditional rotation of the entire probe. Specifically, the receiving module rotates in steps according to the predetermined angular step length through the meshing linkage of the driven gear and the driving gear, ensuring that each rotation can accurately cover the required detection area.

[0036] In terms of functional realization, the probe of the present invention integrates a variety of electromagnetic detection methods, including MBN, MIP and HA. It can realize accurate detection of the magnitude and direction of the principal stress of the residual stress tensor. Through the coordinated work of the excitation coil and the high-resolution magnetic head, the probe can generate uniform and continuous magnetic field excitation, and combined with the high-sensitivity magnetic sensor, receive electromagnetic signal feedback from the surface of the material, thereby realizing the measurement of multiple electromagnetic signals. Especially in residual stress detection, by analyzing the signal in the rectangular detection area and fusing the rotation measurement data, the probe can comprehensively and accurately reflect the stress distribution inside the material.

[0037] In addition, the probe housing, coil skeleton, magnetic head package and other components of the present invention are made by 3D printing technology, and the U-shaped magnetic yoke, excitation coil, magnetic head and magnetic sensor are optimized and fixed by precise bracket limit design inside to ensure the stability and reliability of the entire probe during operation. The use of aviation interface further improves the connection stability and signal transmission performance of the equipment, and can be easily connected to the external signal generator and signal processing system to meet the needs of multi-scenario detection.

[0038] The probe designed in the present invention needs to be used in conjunction with an excitation system and a signal processing system. The overall system schematic diagram is shown in Figure (5). The excitation system includes signal generators, power amplifiers, constant current sources and other modules, which are mainly used to provide the probe with the required low-frequency / high-frequency excitation signal and output the high-frequency orthogonal reference signal required by the phase-locked amplifier; the signal processing system includes low-pass / band-pass filters, signal single-ended / differential amplifiers, phase-locked amplifiers and other modules. The main function is to perform pre-processing such as filtering and amplification on the original voltage signal received by the probe, and transmit the processed signal to the host computer to complete waveform display and eigenvalue extraction. The magnitude and direction of the principal stress of the residual stress tensor are characterized through the existing calibration model and signal fusion analysis.

[0039] The working process of the high-resolution rotating probe and system proposed by the present invention for detecting the residual stress tensor of a material is as follows: (1) Sample preparation and probe positioning: Grind the surface of the sample to be tested to make it smooth and flat. Place the probe at the target detection position of the material to be tested, ensure that the bottom of the probe is in close contact with the sample surface, and define the angle of the receiving module at this time as the reference angle of 0 degrees.

[0040] (2) Low-frequency excitation and signal acquisition: Turn on the excitation system, the signal generator generates low-frequency sinusoidal excitation, which is applied to the excitation coil 3 of the U-shaped magnetic yoke 1 through the power amplifier; the magnetic head 4 in the receiving module is connected to the bandpass filter and signal amplifier in the signal processing system in turn; the signal of the magnetic sensor 5 is connected to the low-pass filter and differential amplifier. The MBN and HA signals are obtained respectively, and the signals are transmitted to the host computer for storage.

[0041] (3) High-frequency excitation and signal acquisition: Change the excitation signal. One path of the signal generator outputs low-frequency sinusoidal excitation, which is applied to the excitation coil 3 through the power amplifier. The other path outputs high-frequency sinusoidal excitation, and generates a high-frequency excitation current with constant amplitude through the constant current source module, which is applied to the high-frequency excitation module of the magnetic head 4. At the same time, the high-frequency signal is applied to the reference end of the phase-locked amplifier as the reference signal for orthogonal demodulation. After the signal of the magnetic head 4 is connected to the phase-locked amplifier for processing, the orthogonal MIP signal is obtained and the signal is transmitted to the host computer.

[0042] (4) Repeated measurement and error elimination: In order to eliminate the influence of magnetic field directionality, low-frequency sinusoidal signals with different amplitude-frequency parameters are used for excitation to obtain electromagnetic feedback signals under different excitation voltages. At the same time, repeated measurements are performed on the above-mentioned signal acquisition process, and the collected data are averaged to reduce experimental errors and improve signal accuracy.

[0043] (5) Rotation module operation and multi-angle detection: Use the gear rotation mechanism to rotate the receiving module at a specified step length to detect electromagnetic signals at different angles at the same position. Follow the process of steps (2) to (4) to collect signals at each angle until a full cycle of signal detection is completed.

[0044] (6) Signal processing and stress characterization: After the detection task is completed, the three electromagnetic signals collected are analyzed and processed, and the data of different excitation parameters are compared and analyzed. The eigenvalues ​​are extracted, the correlation analysis is performed, and the data dimension reduction is performed. In the case of superposition interference of magnetic field anisotropy and stress anisotropy, in order to eliminate the influence of the directionality of the external magnetic field on the measurement results, the angle compensation is performed by integrating the data of different excitation parameters, and then the correlation between multiple eigenvalues ​​and the material residual stress tensor is analyzed. The eigenvalues ​​with high correlation are selected to draw polar coordinate graphs that change with angle. The principal stress direction is finally determined by comprehensive analysis of the processed data, and the magnitude of the principal stress is finally calculated by combining the pre-established calibration curve.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A rotating probe for residual stress tensor detection, characterized in that: It includes a main excitation module, a receiving module, a rotating mechanism and a shell; the main excitation module, the receiving module and the rotating mechanism are all arranged in the shell, the main excitation module is arranged in a U shape inside the shell, the rotating mechanism and the receiving module are arranged on the inner side of the U shape of the main excitation module, and the rotating mechanism is connected to the receiving module to drive the receiving module to rotate.

2. The rotary probe for residual stress tensor detection according to claim 1, characterized in that: The main excitation module comprises a U-shaped magnetic yoke (1), two coil frames (2) and an excitation coil (3); the coil frames (2) are mounted on the yoke arms on both sides of the U-shaped magnetic yoke (1); the excitation coil (3) is wound turn by turn on the two coil frames (2) in the same direction; and raised thin plate structures are provided at both ends of the coil frames (2) for isolating winding layers, thereby forming a uniform and continuous magnetic circuit inside the U-shaped magnetic yoke (1) and the material to be measured.

3. The rotary probe for residual stress tensor detection according to claim 2, characterized in that: The U-shaped magnetic yoke (1) is formed by stacking multiple layers of oriented silicon steel sheets, and its magnetic pole cross section is rectangular; the coil frame (2) is made of nylon material; and the excitation coil (3) is made of enameled wire.

4. The rotary probe for residual stress tensor detection according to claim 1, characterized in that: The receiving module comprises a magnetic head (4), a magnetic sensor (5), a PCB board (13) and a magnetic head package (9). The magnetic head (4) and the magnetic sensor (5) are fixed on the circular PCB board (13) by welding. The magnetic head package (9) is cylindrical, and its inner diameter matches the diameter of the PCB board (13). After the magnetic head (4) and the magnetic sensor (5) are installed, epoxy resin is poured into the interior of the magnetic head package (9).

5. The rotary probe for residual stress tensor detection according to claim 4, characterized in that: The magnetic head (4) comprises a first special-shaped sharp claw yoke (42), a second special-shaped sharp claw yoke (43), an aluminum alloy shielding cover (41), an isolation plate (44) and a glass clamp (45); the first special-shaped sharp claw yoke (42) and the second special-shaped sharp claw yoke (43) are symmetrically placed side by side; a glass clamp (45) is arranged between the sharp claws of the first special-shaped sharp claw yoke (42) and the second special-shaped sharp claw yoke (43) to generate a working gap; an isolation plate (44) is arranged between the first special-shaped sharp claw yoke (42) and the second special-shaped sharp claw yoke (43); and the outside of the magnetic head (4) is covered with an aluminum alloy shielding cover (41).

6. The rotary probe for residual stress tensor detection according to claim 5, characterized in that: The first special-shaped sharp claw magnetic yoke (42) is provided with a receiving coil (46) for receiving the voltage signal of the magnetic Barkhausen noise and the incremental magnetic permeability; the second special-shaped sharp claw magnetic yoke (43) is provided with a high-frequency excitation coil (47) for generating a high-frequency alternating magnetic field; and four pins of the receiving coil (46) and the high-frequency excitation coil (47) are welded on the PCB board (13) for signal transmission.

7. The rotary probe for residual stress tensor detection according to claim 5, characterized in that: The magnetic sensor (5) is a Hall sensor; the first special-shaped sharp claw magnetic yoke (42) and the second special-shaped sharp claw magnetic yoke (43) are formed by stacking multiple layers of oriented silicon steel sheets.

8. The rotary probe for residual stress tensor detection according to claim 1, characterized in that: The rotating mechanism comprises a gear bearing (6), a driving gear (7) and a driven gear (8), wherein the gear bearing (6) is fixed on the housing; the driving gear (7) is mounted on the gear bearing (6), the housing surface is provided with a rectangular opening, and the driving gear (7) is arranged in the rectangular opening; the driven gear (8) is connected to the driving gear (7) through gear meshing, and a cylindrical thin-walled structure is arranged above the driven gear (8), the top end of which is in contact with the housing, and the bottom end is provided with a protrusion which is clamped on the upper end of the magnetic head package (9).

9. The rotary probe for residual stress tensor detection according to claim 2, characterized in that: The housing comprises an upper housing (12), a lower housing (10) and an aviation plug (11); the upper housing (12) and the lower housing (10) are butt-jointed via a snap-fit ​​structure; openings are provided at the bottom of the upper housing (12) and the lower housing (10), which are rectangular openings for two magnetic poles of the U-shaped magnetic yoke (1) and a circular opening for the receiving module; the magnetic poles of the U-shaped magnetic yoke (1) and the magnetic head package (9) of the receiving module extend out of the openings at the bottom of the housing; the aviation plug (11) is arranged on the surface of the housing; and an excitation power supply, a ground wire, a magnetic head signal wire and a magnetic sensor signal wire are respectively connected via the aviation plug (11).

10. A detection method for a rotating probe for residual stress tensor detection, characterized in that: The rotary probe for residual stress tensor detection according to any one of claims 1 to 9 comprises the following steps: First, polish the surface of the sample to be tested, place the probe at the target detection position of the material to be tested, ensure that the bottom of the probe is in contact with the sample surface, and define the angle of the receiving module at this time as the reference angle (0) degrees; The excitation system is turned on, and the signal generator generates a low-frequency sinusoidal excitation, which is applied to the excitation coil (3) of the U-shaped magnetic yoke (1) through a power amplifier; the magnetic head (4) is sequentially connected to the bandpass filter and the signal amplifier in the signal processing system; the magnetic sensor (5) signal is connected to the low-pass filter and the differential amplifier to obtain the magnetic Barkhausen noise and the tangential magnetic field signal respectively, and the signal is transmitted to the host computer for storage; The excitation signal is changed, and one path of the signal generator outputs a low-frequency sinusoidal excitation, which is applied to the excitation coil (3) through a power amplifier; the other path outputs a high-frequency sinusoidal excitation, and a high-frequency excitation current with a constant amplitude is generated through a constant current source module, which is applied to the high-frequency excitation module of the magnetic head (4), and the high-frequency signal is applied to the reference end of the phase-locked amplifier as a reference signal for orthogonal demodulation; after the signal of the magnetic head (4) is connected to the phase-locked amplifier for processing, an incremental magnetic permeability signal is obtained, and the signal is transmitted to the host computer; Take low-frequency excitation with different amplitude-frequency parameters for multiple measurements to obtain electromagnetic feedback signals under different excitation voltages; at the same time, repeat the measurement for the above signal acquisition process and average the acquired data; Use the gear rotation mechanism to rotate the receiving module at a specified step length to collect electromagnetic signals at different angles at the same point until a full cycle of signal detection is completed; After the detection task is completed, the various signals collected are analyzed and processed, the data of different excitation parameters are compared and analyzed, and characteristic value extraction, correlation analysis and data dimension reduction are performed. In order to eliminate the influence of the directionality of the external magnetic field on the measurement results, angle compensation is performed by integrating the data of different excitation parameters, and then a polar coordinate graph that changes with the angle is drawn; the principal stress direction is finally determined by comprehensively analyzing the processed data, and combined with the pre-established calibration curve, the magnitude of the principal stress is finally calculated.

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