Electromagnetic composite nondestructive testing sensor, system and method

Abstract

The present invention discloses an electromagnetic composite nondestructive testing sensor, system and method, belonging to the field of nondestructive testing technology, including an excitation component and a receiving component; the excitation component includes a first excitation coil for receiving an extremely low frequency excitation signal, a low frequency excitation signal or a medium-high frequency excitation signal, and a second excitation coil for receiving a medium-low frequency excitation signal or a high frequency excitation signal. The excitation component and the receiving component working based on excitation signals of different frequencies are integrated into the same sensor, and different excitation signals are introduced into the first excitation coil and the second excitation coil at different times to achieve different nondestructive tests, including eddy current detection, AC electromagnetic field detection, magnetic Barkhausen noise detection, incremental magnetic permeability detection and other nondestructive tests, so as to obtain stress changes caused by microstructures, the influence of incremental magnetic permeability on stress, and the influence of electrical conductivity and magnetic permeability on stress, so as to accurately judge the stress size of components, and provide an experimental verification basis for the study of complex stress theory.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to an electromagnetic composite nondestructive testing sensor, system and method. Background Art

[0002] Ferromagnetic materials are widely used in aerospace, automobiles and ships, high-speed rail bridges, and daily life. However, during the service life of components, as the service time increases and external environmental and human factors such as impact and corrosion, stress concentration and fatigue will occur, resulting in cracks and catastrophic accidents. To solve the above problems, it is necessary to monitor the service status of components during service in real time. Nondestructive testing methods have been well applied in industrial structural health monitoring.

[0003] Existing nondestructive testing methods for stress in ferromagnetic materials generally include ultrasonic testing, X-ray testing, magnetic Barkhausen noise testing, etc. However, ultrasonic testing requires a coupling agent; the use of X-ray testing is limited; the magnetic Barkhausen noise method has many stress influencing factors, such as magnetic permeability, electrical conductivity, microstructure, lattice state, dislocation density, etc. A single nondestructive testing method is not enough to fully extract complete stress information, that is, it is impossible to accurately detect the service status of service components. On this basis, this application proposes to integrate multiple nondestructive testing methods. Furthermore, how to integrate multiple nondestructive testing methods into a sensor and achieve accurate stress detection poses new challenges to the structural design of the sensor. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem that the prior art cannot completely extract the complete stress information of the component, resulting in low detection accuracy, and to provide an electromagnetic composite non-destructive testing sensor, system and method.

[0005] The object of the present invention is achieved through the following technical solutions: an electromagnetic composite nondestructive testing sensor, which includes an excitation component and a receiving component; the excitation component includes a first excitation coil for receiving an extremely low frequency excitation signal, a low frequency excitation signal or a medium-high frequency excitation signal, and a second excitation coil for receiving a medium-low frequency excitation signal or a high frequency excitation signal; the receiving component includes a magnetic head for receiving a longitudinal electromagnetic signal, a magnetic induction intensity detector and a first receiving coil for receiving a transverse electromagnetic signal;

[0006] The sensor also includes a first magnetic yoke for collecting magnetic field; a first excitation coil is wound on the first magnetic yoke; a magnetic head is arranged close to the first magnetic yoke; a magnetic field signal receiver is arranged on the side of the magnetic head; a second excitation coil is wound on the magnetic head; and a first receiving coil is arranged on the side of the magnetic head.

[0007] In one example, the first magnetic yoke is a “U”-shaped magnetic yoke.

[0008] In one example, the magnetic head includes a shielding shell, a micrometer-level slit is provided at the bottom of the shell; a second magnetic yoke is provided in the shell, and a second receiving coil is wound around the second magnetic yoke.

[0009] In one example, the magnetic induction intensity detector is a Hall sensor.

[0010] In one example, the first receiving coil is a multi-layer coaxial PCB coil, and each layer of the PCB coil is reversely wound and connected in series.

[0011] In one example, the sensor further includes a pre-processing circuit for filtering and amplifying processing, and the pre-processing circuit is connected to the magnetic head and / or the magnetic field signal receiver and / or the first receiving coil and / or the excitation coil.

[0012] In one example, the receiving component, the second excitation coil and the pre-processing circuit are arranged on a PCB circuit board, and the receiving component is arranged at the center of the first magnetic yoke.

[0013] It should be further explained that the technical features corresponding to the above sensor examples can be combined or replaced with each other to form a new technical solution.

[0014] The present invention also includes an electromagnetic composite nondestructive testing system, which includes the sensor formed by any one of the above examples or a combination of multiple examples, and also includes an excitation source and a data processing unit, the excitation source is connected to the excitation coil; the data processing unit is connected to the magnetic head, the magnetic field signal receiver and the first receiving coil.

[0015] The present invention also includes an electromagnetic composite nondestructive testing method, which is applied based on the sensor formed by any one of the above examples or a combination of multiple examples, and specifically includes the following steps:

[0016] Passing a high-frequency AC signal into the second excitation coil for eddy current detection;

[0017] A medium-high frequency AC signal is introduced into the first excitation coil for AC electromagnetic field detection;

[0018] Passing an extremely low frequency AC signal into the first excitation coil for detecting magnetic Barkhausen noise;

[0019] A very low frequency AC signal is fed into the first excitation coil, and a medium and low frequency AC signal is fed into the second excitation coil for incremental magnetic permeability detection;

[0020] Perform any two or more of the above electromagnetic tests;

[0021] Perform any two or more of the above electromagnetic tests.

[0022] In one example, the method further includes:

[0023] The magnetic head and / or the first receiving coil receives the detection signal, and the stress of the component is determined according to the change in the amplitude of the detection signal.

[0024] It should be further explained that the technical features corresponding to the above detection method examples can be combined or replaced with each other to form a new technical solution.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. In one example, an excitation component and a receiving component that work based on excitation signals of different frequencies are integrated into the same sensor. Different excitation signals are introduced into the first excitation coil and the second excitation coil at different times to achieve different nondestructive tests, including eddy current testing, AC electromagnetic field testing, magnetic Barkhausen noise testing, incremental magnetic permeability testing and other nondestructive tests. The stress changes caused by the microstructure, the influence of the incremental magnetic permeability on the stress, and the influence of the electrical conductivity and magnetic permeability on the stress can be obtained, thereby accurately judging the stress size of the component and providing an experimental verification basis for the study of complex stress theory.

[0027] 2. In one example, the yoke is used to enhance the excited magnetic field and thus locally magnetize the test piece. The magnetized area of ​​the "U"-shaped yoke is easy to locate, and has low processing difficulty and low cost.

[0028] 3. In one example, the magnetic field signals outside the gap of the head shielding shell will be shielded by the shielding shell, and only the electromagnetic signals at the gap are allowed to pass, so as to avoid the influence of the noise signal on the detection signal received by the second receiving coil, thereby obtaining a magnetic head with high spatial resolution, which can measure the information at the magnetic domain wall and has the ability to measure the stress of micro-objects.

[0029] 4. In one example, the Hall sensor has high sensitivity and is used to accurately detect the magnetic induction intensity.

[0030] 5. In one example, multiple layers of coaxial receiving coils connected in series can improve detection sensitivity while lowering the optimal detection frequency and effectively reduce the requirements for the excitation signal.

[0031] 6. In one example, the pre-processing circuit is used to perform pre-processing such as filtering and amplifying the excitation signal or the received detection signal, which can reduce electromagnetic interference and improve detection accuracy.

[0032] 7. In one example, the receiving component is located at the center of the first magnetic yoke, which can ensure the quality of signal transmission, maximize the energy transmission efficiency, and achieve the best detection effect.

[0033] 8. In one example, by passing excitation signals of different frequencies into two excitation coils, a variety of non-destructive tests can be performed using a single sensor, and then the stress magnitude of the test piece can be comprehensively judged based on a variety of detection methods, thereby improving the accuracy of stress detection of the test piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The same reference numerals are used in these drawings to represent the same or similar parts. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0035] Figure 1 is a schematic diagram of the sensor structure in an example of the present invention;

[0036] FIG2( a ) is a front view of a first magnetic yoke in an example of the present invention;

[0037] FIG2( b ) is a side view of a first magnetic yoke in an example of the present invention;

[0038] FIG2( c ) is a top view of a first magnetic yoke in an example of the present invention;

[0039] FIG3( a ) is a front view of a first excitation coil in an example of the present invention;

[0040] FIG3( b ) is a side view of a first excitation coil in an example of the present invention;

[0041] FIG3( c ) is a top view of a first excitation coil in an example of the present invention;

[0042] FIG4( a ) is a front view of the external structure of a magnetic head in an example of the present invention;

[0043] FIG4( b ) is a side view of the external structure of a magnetic head in an example of the present invention;

[0044] FIG4( c ) is a bottom view of the external structure of a magnetic head in an example of the present invention;

[0045] Figure 5 is a schematic diagram of the internal structure of a magnetic head in an example of the present invention;

[0046] Figure 6 is a schematic diagram of a first receiving coil in an example of the present invention;

[0047] FIG. 7( a ) is a front view of a second excitation coil in an example of the present invention;

[0048] FIG7( b ) is a side view of a second excitation coil in an example of the present invention;

[0049] FIG7( c ) is a top view of a second excitation coil in an example of the present invention;

[0050] Figure 8 is a circuit schematic diagram of a pre-processing circuit in an example of the present invention;

[0051] Fig. 9 It is a schematic diagram of an electromagnetic composite nondestructive testing system in an example of the present invention;

[0052] Fig.10 It is a flow chart of the electromagnetic composite nondestructive testing method in an example of the present invention;

[0053] Fig.11 A schematic diagram of an excitation setting mode in an example of the present invention;

[0054] Fig.12 is a schematic diagram of eddy current detection results in an example of the present invention;

[0055] Fig.13 It is a schematic diagram of the detection result of the alternating current electromagnetic field method in an example of the present invention;

[0056] Fig.14 It is a schematic diagram of the detection result of the magnetic Barkhausen noise method in an example of the present invention;

[0057] Fig.15 This is a schematic diagram of the test results of the incremental magnetic permeability method in an example of the present invention.

[0058] In the figure: a first excitation coil 11, a second excitation coil 12, a magnetic head 21, a second magnetic yoke 211, a second receiving coil 212, a slit 213, a magnetic induction intensity detector 22, a first receiving coil 23, a perforation 231, a first magnetic yoke 3, a pre-processing circuit 4, and a test piece 5. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] In the description of the present invention, it should be noted that the directions or positional relationships indicated by "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are directions or positional relationships based on the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0061] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0063] In one example, an electromagnetic composite nondestructive testing sensor, such as Figure 1 As shown, it specifically includes an excitation component and a receiving component; the excitation component includes a first excitation coil 11 for receiving an extremely low frequency excitation signal, an extremely low frequency excitation signal, a low frequency excitation signal or a medium and high frequency excitation signal, and a second excitation coil 12 for receiving a medium and low frequency excitation signal or a high frequency excitation signal, wherein the excitation signals are all AC signals; the receiving component includes a magnetic head 21 for receiving a longitudinal electromagnetic signal, a magnetic induction intensity detector 22, and a first receiving coil 23 for receiving a transverse electromagnetic signal, that is, the magnetic head 21 and the first receiving coil 23 are used to receive a detection signal (electromagnetic signal) carrying deformation information (stress change information) of the test piece 5. It should be noted that the low frequency, medium and high frequency, medium and low frequency, and high frequency referred to in this application follow the definition of wave frequency bands in the field of communication, that is, the extremely low frequency band ranges from 3Hz to 30Hz; the low frequency band ranges from 30Hz to 150Hz; the medium and low frequency band ranges from 150Hz to 500Hz; the medium and high frequency band ranges from 500Hz to 5KHz; and the high frequency band ranges from 5K to 16KHz.

[0064] Furthermore, it is preferred to first give the second excitation coil 12 a low-amplitude, high-frequency signal, and then perform eddy current detection on the test piece 5; then give the first excitation coil 11 a high-amplitude, medium- and high-frequency signal, and then perform AC electromagnetic field detection on the test piece 5; then give the first excitation coil 11 a high-amplitude, extremely low-frequency signal, and then perform magnetic Barkhausen noise detection on the test piece 5; finally, give the first excitation coil 11 a high-amplitude, extremely low-frequency signal, and at the same time give the second excitation coil 12 a low-amplitude, medium- and low-frequency signal, and then perform incremental magnetic permeability detection on the test piece 5.

[0065] Furthermore, the sensor also includes a first magnetic yoke 3 for collecting magnetic field; the first excitation coil 11 is wound around the first magnetic yoke 3; the magnetic head 21 is arranged close to the first magnetic yoke 3 to facilitate receiving electromagnetic signals; the magnetic field signal receiver is arranged on one side of the magnetic head 21; the second excitation coil 12 is wound on the magnetic head 21; the first receiving coil 23 is arranged on the other side of the magnetic head 21, and preferably the first receiving coil 23 and the magnetic field signal receiver are symmetrically arranged on both sides of the magnetic head 21.

[0066] When high-frequency alternating current (high-frequency excitation signal) is applied to the second excitation coil 12 above the test piece 5, eddy currents will be formed on the test piece 5. The feedback information of the eddy currents can be received by the magnetic head 21 and / or the first receiving coil 23, thereby realizing eddy current detection, which is used to explore the influence of conductivity on stress.

[0067] When alternating current with a frequency above kilohertz (medium or high frequency excitation signal) is applied to the first excitation coil 11, a uniform electric field will be formed on the surface of the test piece 5, and the electric field signal will be received by the magnetic head 21 and / or the first receiving coil 23, thereby realizing AC electromagnetic field detection, which is used to explore the influence of electrical conductivity and magnetic permeability on stress.

[0068] When extremely low frequency alternating current is passed through the first excitation coil 11 wound around the first magnetic yoke 3, a changing magnetic field is generated. The first magnetic yoke 3 further enhances the magnetic field to generate a larger magnetic field. The tested piece 5 (component) will be locally magnetized. During this process, a series of electromagnetic pulse noises will be generated. This noise can be received by the magnetic head 21 and / or the first receiving coil 23 and fed back in the form of voltage, thereby realizing magnetic Barkhausen noise detection, which is used to explore stress changes caused by microstructures.

[0069] On the basis that the test piece 5 is magnetized, that is, an extremely low frequency excitation signal is applied to the first excitation coil 11, and a medium and low frequency excitation signal is applied to the second excitation coil 12 above the test piece 5. At this time, there is a superimposed magnetic field at the test piece 5, which will cause some small hysteresis loops to appear on the hysteresis loop that originally appeared during magnetization. The increment can be detected by the magnetic head 21 and / or the first receiving coil 23, thereby realizing incremental magnetic permeability detection, which is used to explore the influence of incremental magnetic permeability on stress.

[0070] The existing single detection method such as eddy current detection has low accuracy in stress detection of the test piece 5 because the detection signal is sensitive to a variety of influencing factors other than stress, such as residual stress and inclusions, material non-uniformity, plastic deformation, etc. In this example, the excitation coils that work based on excitation signals of different frequencies and the receiving components are integrated into the same sensor, and different non-destructive tests are achieved by passing different frequency excitation signals to the first excitation coil 11 and / or the second excitation coil 12 at different times, including eddy current detection, AC electromagnetic field detection, magnetic Barkhausen noise detection, incremental magnetic permeability detection and other non-destructive tests. When the stress of the test point of the test piece 5 is different, the amplitude, phase, frequency band, etc. of the signal received by the magnetic head 21 or the first receiving coil 23 will change. This change includes the stress. Change information, in this application, by controlling the detection timing, that is, passing different frequency excitation signals into the first excitation coil 11 and / or the second excitation coil 12 at different times to achieve different non-destructive detection, and performing signal feature extraction and fusion, it is possible to obtain the stress changes caused by the microstructure, the influence of the incremental magnetic permeability on the stress, the influence of the electrical conductivity and the magnetic permeability on the stress, judge the stress state of the test piece 5 from multiple aspects, and then separate the influence of factors such as material inhomogeneity and plasticity, thereby improving the accuracy of stress evaluation and providing an experimental verification basis for the study of complex stress theory.

[0071] In one example, as shown in FIG2 , the first yoke 3 is a “U”-shaped yoke. Specifically, the yoke is made of stamped and stacked silicon steel sheets. The excited magnetic field can be enhanced to locally magnetize the test piece 5. Compared with ferrite, the yoke stamped and stacked by silicon steel sheets can be freely processed in shape, and the magnetic induction intensity is high and the cost is low; the magnetization area of ​​the “U”-shaped yoke is between the two legs of the “U”-shaped yoke, which is easy to locate the magnetization area.

[0072] In one example, as shown in Figure 3, the first excitation coil 11 is wound with copper wire, specifically a hollow rectangular coil wound on the cross section of the first magnetic yoke 3. Preferably, the first excitation coil 11 is wound at the center of the cross section of the magnetic yoke, and is used to generate a magnetic field and excitation of an AC electromagnetic field method. Depending on the frequency of the excitation source signal, different methods of non-destructive electromagnetic detection can be achieved; more specifically, a lead is led out from the head and tail ends of the first excitation coil 11, and the lead is directly welded to the signal preprocessing circuit PCB as an external excitation input port, that is, the output end of the excitation source is connected to the excitation input port.

[0073] In one example, as shown in FIG4 , the outside of the magnetic head 21 is a shielding shell, and a micrometer-level slit 213 is provided at the bottom of the shell; a second magnetic yoke 211 is provided inside the shell, and a second receiving coil 212 is wound around the second magnetic yoke 211. Specifically, Figure 5As shown, the second magnetic yoke 211 is a "U"-shaped magnetic yoke, on which a second receiving coil 212 made of copper is wound, for receiving the longitudinal detection signal of the test piece 5. When the magnetic head 21 receives the electromagnetic signal, the magnetic field outside the gap under the shielding cover will be shielded by the shielding shell and cannot affect the internal signal reception, thereby obtaining a magnetic head 21 with high spatial resolution, which can measure the information at the magnetic domain wall and has the ability to measure the stress of micro-objects.

[0074] In one example, the magnetic induction intensity detector 22 is a Hall sensor SS496A1, which has a magnetic field measurement range of ±840 Gauss and a sensitivity of 2.500mV / Gauss, and is used to receive a magnetic signal in a direction parallel to the test piece 5, and then detect the magnetic induction intensity of the magnetic field. As an option, the Hall sensor is also used to detect leakage magnetic signals. More specifically, the three data pins of the Hall sensor are connected to the pre-processing circuit 4.

[0075] In one example, if Figure 6 As shown, the first receiving coil 23 is a multi-layer coaxial PCB coil, and each layer of PCB coil is reversely wound and connected in series. Specifically, in this example, the first receiving coil 23 is a 4-layer coaxial PCB coil, which is used to receive the horizontal axis direction signal of the test piece 5; the coils between each layer are connected in series through the perforation 231, and the winding direction of each layer of coils is opposite to that of the upper layer (adjacent). More specifically, solder joints are reserved at the head and tail ends of the PCB coil, and the solder joints are connected to the pre-processing circuit 4. In this example, the multi-layer coaxial receiving coils connected in series can improve the detection sensitivity, while reducing the optimal detection frequency, and can also effectively reduce the requirements for the excitation signal.

[0076] In one example, as shown in Figure 7, the second excitation coil 12 is wound on the body of the magnetic head 21. The second excitation coil 12 is preferably wound on the basis of the Hall sensor and the first receiving coil 23 arranged on both sides of the magnetic head 21, that is, the second excitation coil 12 is wound on the magnetic head 21, the Hall sensor, and the first receiving coil 23, and is used to generate eddy current excitation, and can also be used as one of the excitations of incremental magnetic permeability.

[0077] In one example, the electromagnetic composite nondestructive testing sensor further includes a pre-processing circuit 4 for filtering and amplifying processing. In this example, the pre-processing circuit 4 is connected to the receiving component. Of course, as an option, the excitation source can be connected to the excitation component through the pre-processing circuit 4 (signal pre-processing circuit). Specifically, Figure 8As shown, the pre-processing circuit 4 includes a 0.01Hz high-pass filter circuit, an operational amplifier circuit based on an INA849 operational amplifier chip, and a 1MHz low-pass passive filter circuit connected in sequence. More specifically, the pre-processing circuit 4 also includes a front-end data interface, which is connected to the output end of the receiving component through the data interface; the pre-processing circuit 4 also includes a back-end aviation plug interface, which is connected to the back-end data processing unit through the aviation plug interface; the pre-processing circuit 4 also includes a level conversion circuit, which is used to realize voltage conversion and provide corresponding working voltages for each circuit. In this example, the detection signals containing deformation information of the test piece 5 received by the receiving component, i.e., the second receiving coil 212, the Hall sensor, and the first receiving coil 23 in the magnetic head 21, are all pre-processed by the pre-processing circuit 4 by filtering, amplification, etc., and then further input into the back-end data processing unit for data analysis to obtain the stress information of the test piece 5, thereby increasing the signal-to-noise ratio of the signal, reducing electromagnetic interference, and improving the detection accuracy.

[0078] In one example, the receiving component, the second excitation coil 12 and the pre-processing circuit 4 are arranged on a PCB circuit board, and the receiving component is arranged at the center of the first magnetic yoke 3. Specifically, the receiving component is located at the center of the first magnetic yoke 3, which can ensure the signal transmission quality, maximize the energy transmission efficiency, and achieve the best detection effect. More specifically, the electromagnetic composite non-destructive testing sensor also includes a fixing base, and the base is preferably a "U"-shaped base with two legs of unequal heights, preferably made of resin, and the first magnetic yoke 3 is installed on one leg of the base, and the PCB circuit board is installed in the gap between the two legs of the first magnetic yoke 3. The other end of the PCB circuit board is fixed by the other leg of the base, that is, the PCB circuit board runs through the entire base, so as to realize the integrated installation of the sensor and occupy a small volume; the excitation component and the detection component are integrated for easy detection.

[0079] The present invention also includes an electromagnetic composite nondestructive testing system, which has the same inventive concept as the above electromagnetic composite nondestructive testing sensor, and the system includes a sensor formed by any one of the above examples or a combination of multiple examples, such as Fig. 9 As shown, it also includes an excitation source and a data processing unit, wherein the excitation source is connected to the excitation component, and the data processing unit is connected to the receiving component. The excitation source is an AC signal source, specifically a signal generator. The data processing unit includes a bidirectionally connected data preprocessing module and a data processing center. In this example, the data preprocessing module is an FPGA, which is used to preprocess the electromagnetic detection signal; the data processing center is an industrial computer (PC), which is used to analyze the electromagnetic detection signal, and then accurately obtain the stress information of the test piece 5.

[0080] In one example, the system also includes a signal preprocessing circuit and a preprocessing circuit 4, both of which are used for preprocessing such as signal filtering and amplification. The excitation source is connected to the excitation component (first excitation coil 11, second excitation coil 12) via the signal preprocessing circuit, and the receiving component (magnetic head 21, first receiving coil 23, Hall sensor) is connected to the back-end data processing unit via the preprocessing circuit 4.

[0081] The present invention also includes an electromagnetic composite nondestructive testing method, which has the same inventive concept as the electromagnetic composite nondestructive testing sensor described above, and the method is applied based on a sensor formed by any one of the above examples or a combination of multiple examples, such as Fig.10 As shown, the specific steps include:

[0082] S1: Pass a high-frequency AC signal to the second excitation coil for eddy current detection;

[0083] S2: passing a medium-high frequency AC signal into the first excitation coil for AC electromagnetic field detection;

[0084] S3: Passing an extremely low frequency AC signal into the first excitation coil for performing magnetic Barkhausen noise detection;

[0085] S4: A very low frequency AC signal is input to the first excitation coil, and a medium and low frequency AC signal is input to the second excitation coil for incremental magnetic permeability detection.

[0086] The present application controls the detection sequence, that is, performs eddy current detection, AC electromagnetic field detection, magnetic Barkhausen noise detection, and incremental magnetic permeability detection in sequence, so that the amplitude of the excitation signal increases from small to large (or increases from small to large and remains constant), so that the tested piece 5 always maintains the initial magnetization state, and the amplitude of the excitation signal on the two excitation coils is always smaller than the amplitude of the detection signal. Then, the detection sequence is controlled to match the detection method with the optimal stress sensitivity at a specific excitation working point. On this basis, corresponding detection signals are extracted based on different detection methods. Different detection signal characteristics have different sensitivities to stress and material non-uniformity. Therefore, on the basis of the optimal stress sensitivity detection sequence, a data processing method based on multi-parameter feature selection and extraction is adopted, which can separate the influence of factors such as stress and material non-uniformity on the detection signal, thereby improving the accuracy of stress assessment.

[0087] Specifically, the sensor of the present application is placed close to the surface of the test piece 5, such as Fig.11 As shown, the given excitation signal model of the electromagnetic composite nondestructive testing method in this example is:

[0088] First, a 1Vpp, 30KHz excitation signal is given to the second excitation coil 12 (corresponding to excitation 2) to realize eddy current detection (EC); then an alternating current electromagnetic field detection (ACFM) is performed, and a 10Vpp, 1kHz excitation signal is applied to the first excitation coil 11; then a 10Vpp, 10Hz sinusoidal excitation signal is given to the first excitation coil 11 (corresponding to excitation 1) to excite the magnetic Barkhausen noise detection (MBN) of the test piece 5; finally, an incremental magnetic permeability detection (Sig) is performed, and a 10Vpp, 10Hz sinusoidal signal is applied to the first excitation coil 11, and a 0.5Vpp, 500Hz excitation signal is applied to the second excitation coil 12. During the excitation process, the test piece 5 is in a stretched state. All four methods are performed without changing the measurement position, which can ensure reliability. In each excitation time period, each nondestructive testing method produces different electromagnetic effects on the test piece 5, and different detection methods are distinguished by different electromagnetic effects.

[0089] In one example, the method further includes:

[0090] The detection signal is received by the magnetic head 21 and the first receiving coil 23, and the stress of the component is determined according to the change in the amplitude of the detection signal. In this example, by passing different frequency excitation signals to the two excitation coils, multiple non-destructive tests can be performed through a single sensor, that is, the stress of the test piece 5 is analyzed by the eddy current method, the AC electromagnetic field method, the magnetic Barkhausen noise method, and the incremental magnetic permeability method respectively, and the stress of the test piece 5 is comprehensively judged, thereby improving the accuracy of the stress detection of the test piece 5.

[0091] Specifically, when eddy current detection is performed in the first stage corresponding to step S1, given the corresponding excitation, eddy currents will be generated on the surface of the test piece 5. When the tension changes the conductivity of the test piece 5, the size of the eddy current will change. The magnetic head 21 receives the change and feeds back in the form of voltage. The eddy current change is obtained through its amplitude to determine the stress size.

[0092] Furthermore, when the AC electromagnetic field detection is performed in the second stage corresponding to step S2, a corresponding excitation is given. At this time, a uniform electric field will be generated on the test piece 5. The magnitude of the electric field will change with the change of the conductivity of the test piece 5. At the same time, it carries certain magnetic information. The tensile stress will cause the conductivity and permeability to change over time. The magnetic head 21 and the first receiving coil 23 can receive the changes in conductivity and permeability in this process. Through data processing, the average peak value is extracted to determine the magnitude of the tensile stress.

[0093] Furthermore, in the third stage corresponding to step S3, when the magnetic Barkhausen noise method is used for detection, the given excitation can magnetize the test piece 5, and the dynamic behavior of the magnetic domains and domain walls inside the test piece 5 will be captured by the magnetic head 21; at the same time, the first receiving coil 23 and the Hall sensor will receive the transverse electromagnetic signal, and the results of the two can be mutually verified and compared. Through data processing, the root mean square value of the detection signal received by the magnetic head 21 is extracted to determine the magnitude of the tensile stress at this time, and the specific calculation formula is:

[0094]

[0095] Among them, X rms represents the root mean square root of the detection signal, which is proportional to the stress magnitude; X i represents the received detection signal sequence; N represents the number of detection signals, which is used as the upper limit of the summation calculation; i represents the ordinal number of the detection signal; σ represents the stress of the test piece 5.

[0096] Furthermore, when the incremental magnetic permeability detection is performed in stage four corresponding to step S4, the corresponding excitation is given, and high-frequency eddy currents are added to the test piece 5 on the basis of magnetization for superposition. According to the different magnetic permeabilities of the test piece 5, the superimposed field strength will be different. The magnetic head 21 receives this field strength change, and the field strength transformation and stress change can be obtained by drawing a butterfly diagram.

[0097] In order to better illustrate the technical effect of the present invention, the multi-nondestructive testing method fusion sensor based on the high spatial resolution magnetic head 21 of the present invention is used to perform a tensile test on a silicon steel sheet. The excitation given method refers to the excitation signal parameters in the above-mentioned electromagnetic composite nondestructive testing method, and the tensile forces are 0N, 300N, 600N, 900N, 1200N, and 1500N respectively. The results of each method measured under each tensile stress are shown in the figure, and the horizontal axis of each figure represents the tensile force, and the vertical axis represents the detection signal amplitude. Among them, Fig.13 This is the detection result of the AC electromagnetic field method. It can be seen that as the tensile stress increases, the signal amplitude decreases, which is consistent with Fig.12 Compared with the eddy current test result graph, the AC electromagnetic field test does not have a trend of first decreasing and then increasing. In both cases, the tensile stress mainly affects the conductivity of the test piece 5. However, the AC electromagnetic field method also includes some magnetic characteristics, which is different from Fig.12 The difference can be clearly seen in comparison. Fig.14 This is the test result diagram of the magnetic Barkhausen noise method. It can be seen that with the continuous increase of tensile stress, the root mean square value of the magnetic Barkhausen noise signal continues to increase, roughly linearly. In this process, microstructural changes such as domain wall transitions are the main factors affecting stress. Fig.15This is the test result of the incremental permeability method. It can be seen that as the tensile stress increases, the peak value of the butterfly graph continues to increase. From the above results, it can be seen that different methods have different sensitivities to stress and different dominant factors. The various non-destructive testing methods involved in this application can measure time in situ, ensure the consistency of the measurement points, and extract the main influencing factors of different stress stages, thereby providing an experimental basis for complex stress assessment theory.

[0098] The above specific implementation methods are detailed descriptions of the present invention. It cannot be determined that the specific implementation methods of the present invention are limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. An electromagnetic composite nondestructive testing sensor, characterized in that: It includes an excitation component and a receiving component; the excitation component includes a first excitation coil for receiving an extremely low frequency excitation signal, a low frequency excitation signal or a medium-high frequency excitation signal, and a second excitation coil for receiving a medium-low frequency excitation signal or a high frequency excitation signal; the receiving component includes a magnetic head for receiving a longitudinal electromagnetic signal, a magnetic induction intensity detector and a first receiving coil for receiving a transverse electromagnetic signal; The sensor also includes a first magnetic yoke for collecting magnetic field; a first excitation coil is wound on the first magnetic yoke; a magnetic head is arranged close to the first magnetic yoke; a magnetic field signal receiver is arranged on the side of the magnetic head; a second excitation coil is wound on the magnetic head; and a first receiving coil is arranged on the side of the magnetic head; First, a low-amplitude high-frequency signal is given to the second excitation coil, and then eddy current detection is performed on the test piece; then a high-amplitude medium-high frequency signal is given to the first excitation coil, and then AC electromagnetic field detection is performed on the test piece; then a high-amplitude extremely low-frequency signal is given to the first excitation coil, and then magnetic Barkhausen noise detection is performed on the test piece; finally, a high-amplitude extremely low-frequency signal is given to the first excitation coil, and at the same time a low-amplitude medium-low frequency signal is given to the second excitation coil, and then incremental magnetic permeability detection is performed on the test piece; The ultra-low frequency range is 3Hz-30Hz; the low frequency range is 30Hz-150Hz; the mid-low frequency range is 150Hz-500Hz; the mid-high frequency range is 500Hz-5KHz; the high frequency range is 5K-16KHz; The detection signal is received by the magnetic head and / or the first receiving coil, and the stress of the component is determined based on the characteristic evaluation of the detection signal.

2. The electromagnetic composite nondestructive testing sensor according to claim 1, characterized in that: The first magnetic yoke is a "U"-shaped magnetic yoke.

3. The electromagnetic composite nondestructive testing sensor according to claim 1, characterized in that: The magnetic head comprises a shielding shell, a micrometer-level slit is arranged at the bottom of the shell; a second magnetic yoke is arranged inside the shell, and a second receiving coil is wound around the second magnetic yoke.

4. The electromagnetic composite nondestructive testing sensor according to claim 1, characterized in that: The magnetic induction intensity detector is a Hall sensor.

5. The electromagnetic composite nondestructive testing sensor according to claim 1, characterized in that: The first receiving coil is a multi-layer coaxial PCB coil, and each layer of the PCB coil is reversely wound and connected in series.

6. The electromagnetic composite nondestructive testing sensor according to claim 1, characterized in that: The sensor further comprises a pre-processing circuit for filtering and amplifying processing, and the pre-processing circuit is connected to the magnetic head and / or the magnetic field signal receiver and / or the first receiving coil and / or the excitation coil.

7. The electromagnetic composite nondestructive testing sensor according to claim 6, characterized in that: The receiving component, the second excitation coil and the pre-processing circuit are arranged on a PCB circuit board, and the receiving component is arranged at the center of the first magnetic yoke.

8. An electromagnetic composite nondestructive testing system, characterized in that: The system includes the sensor described in any one of claims 1-7, and also includes an excitation source and a data processing unit, wherein the excitation source is connected to the excitation coil; the data processing unit is connected to the magnetic head, the magnetic field signal receiver and the first receiving coil.

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