Alternating-current magnetized magnetostrictive flexible probe, detection device and detection method

Abstract

The invention relates to an alternating current magnetization magnetostriction flexible probe, a detection device and a detection method.The flexible probe comprises a spiral magnetization coil and a zigzag coil, the spiral magnetization coil is attached to a to-be-detected part, and the spiral magnetization coil is configured to generate an alternating magnetic field by loading alternating current; the zigzag coil is arranged at a position between the spiral magnetizing coil and a to-be-detected part, the zigzag coil is configured to generate a dynamic magnetic field by loading pulse string current, and the flexible probe generates magnetostrictive vibration based on the alternating magnetic field and the dynamic magnetic field and excites an ultrasonic signal; the spiral magnetizing coil is adopted to replace a traditional permanent magnet to generate an alternating magnetic field, and the spiral magnetizing coil and the zigzag coil can be flexibly bent, so that the spiral magnetizing coil and the zigzag coil are effectively attached to the surface of a to-be-detected part and particularly suitable for curved surface detection of the to-be-detected part, and flexible detection can be achieved while the size of the probe is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic ultrasonic nondestructive testing, and in particular to an AC magnetized magnetostrictive flexible probe, a testing device and a testing method. Background Art

[0002] Magnetostriction, as a method of electromagnetic ultrasonic testing technology, has the advantages of no need for coupling agent, non-contact, and simple structure, and is widely used in the field of non-destructive testing.

[0003] Traditional magnetostrictive probes mostly use permanent magnets or DC coils to provide bias magnetic fields. Permanent magnets are large in size and cannot conform to curved surfaces. The DC magnetization current is large, generally reaching hundreds of amperes or even thousands of amperes, so high experimental conditions are required. Summary of the invention

[0004] In view of this, an AC magnetized magnetostrictive flexible probe, a detection device and a detection method are provided.

[0005] In a first aspect, the present invention provides an AC magnetized magnetostrictive flexible probe, the flexible probe comprising a spiral magnetization coil and a zigzag coil, the spiral magnetization coil being attached to a part to be measured, the spiral magnetization coil being configured to generate an alternating magnetic field by loading an AC current; the zigzag coil being disposed at a position between the spiral magnetization coil and the part to be measured, the zigzag coil being configured to generate a dynamic magnetic field by loading a pulse train current, wherein the flexible probe generates magnetostrictive vibration based on the alternating magnetic field and the dynamic magnetic field, and excites an ultrasonic signal.

[0006] Furthermore, the flexible probe also includes a first flexible shell, which is cylindrical, and the spiral magnetization coil is wound on the first flexible shell. The first flexible shell is configured to be deformable under the action of external force so as to be attached to the surface of the part to be measured.

[0007] Furthermore, the flexible probe also includes a second flexible shell, which is in sheet shape, and the meander coil is built into the second flexible shell through FPC process. The second flexible shell is configured to be deformable under the action of external force so as to be attached to the surface of the part to be tested.

[0008] Furthermore, the flexible probe further comprises a clock module electrically connected to the spiral magnetization coil and the meandering coil, and the clock module is configured to control the loading timing of the alternating current and the pulse train current.

[0009] Furthermore, the clock module includes the synchronization circuit and the gating circuit electrically connected to the spiral magnetization coil and the zigzag coil, the synchronization circuit is used to control the excitation time of the alternating current and the pulse train current to be the same, and the gating circuit controls the number of pulse trains of the pulse train current based on the frequencies of the alternating current and the pulse train current.

[0010] In a second aspect, the present invention provides a detection device based on an AC magnetized magnetostrictive flexible probe, comprising the AC magnetized magnetostrictive flexible probe as described above, the detection device also comprising an AC excitation power supply, a pulse train excitation power supply and a signal receiving module, the AC excitation power supply is electrically connected to the spiral magnetization coil for loading an AC current to the spiral magnetization coil, the pulse train excitation power supply is electrically connected to the zigzag coil for loading a pulse train current to the zigzag coil, the signal receiving module is electrically connected to the zigzag coil for receiving an induced voltage signal generated by the zigzag coil.

[0011] In a third aspect, the present invention provides a detection method based on an AC magnetized magnetostrictive flexible probe, which is applied to the detection device based on an AC magnetized magnetostrictive flexible probe as described above, comprising: Two flexible probes are arranged at intervals and are both attached to the surface of the part to be tested, wherein one of the flexible probes is an ultrasonic excitation probe and the other flexible probe is an ultrasonic receiving probe; The AC excitation power supply loads AC current to the spiral magnetization coils in the ultrasonic excitation probe and the ultrasonic receiving probe, thereby generating an alternating positive and negative alternating magnetic field at two locations on the surface of the part to be tested; The pulse train excitation power supply loads the pulse train current to the zigzag coil in the ultrasonic excitation probe, thereby generating a dynamic magnetic field in the part to be tested; The interaction between the alternating magnetic field and the dynamic magnetic field generates magnetostrictive vibration on the surface of the part to be tested and stimulates ultrasonic signals; The ultrasonic receiving probe receives the ultrasonic wave generated by the ultrasonic excitation probe and the ultrasonic wave reflected from the defect of the part to be tested, and an induced voltage signal is generated in the meandering coil in the ultrasonic receiving probe; The signal receiving module captures the induced voltage signal and analyzes and processes it to obtain the detection result.

[0012] Furthermore, the loading sequence of the AC excitation power supply and the pulse train excitation power supply is controlled by a clock module, wherein the clock module synchronously turns on the AC excitation power supply and the pulse train excitation power supply.

[0013] Furthermore, the control of the loading timing of the AC excitation power supply and the pulse train excitation power supply by the clock module includes: The clock module captures the phase of the AC current, and when the AC current value increases from zero, the synchronization circuit of the clock module sends a trigger signal to the pulse train excitation power supply; The gate circuit of the clock module is turned on, and the pulse train excitation power supply generates a preset number of pulse train currents in the zigzag coil in the ultrasonic excitation probe, thereby generating a dynamic magnetic field with a preset time width in the part to be tested.

[0014] Furthermore, the signal receiving module transmits the captured induced voltage signal to the oscilloscope.

[0015] Compared with the existing technology, a spiral magnetization coil is used to replace the traditional permanent magnet to generate a bias magnetic field. Both the spiral magnetization coil and the zigzag coil can be flexibly bent, so as to effectively fit the surface of the part to be tested, and is particularly suitable for curved surface detection of the part to be tested. It can effectively reduce the volume of the probe and realize flexible detection. A spiral magnetization coil is used to provide an alternating magnetic field. The vibration influencing factors of the magnetostrictive force are jointly determined by the alternating magnetic field intensity, the dynamic magnetic field intensity and the magnetostriction amount. Effective excitation of ultrasound can be achieved at a relatively low current, and the signal-to-noise ratio is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of an AC magnetized magnetostrictive flexible probe for detecting panel parts provided in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of an AC magnetized magnetostrictive flexible probe for detecting curved surface parts provided in an embodiment of the present invention; Figure 3 A schematic diagram of the overall structure of a detection device based on an AC magnetized magnetostrictive flexible probe provided in an embodiment of the present invention; Figure 4 The experimental diagram of the SH wave initial wave and direct wave obtained by detecting a 1 mm thick ferromagnetic 430 stainless steel plate using a detection device based on an AC magnetized magnetostrictive flexible probe provided in an embodiment of the present invention; Figure 5 A schematic diagram of a detection method based on an AC magnetized magnetostrictive flexible probe provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0018] like Figure 1-2As shown, in the first aspect, the present invention provides an AC magnetized magnetostrictive flexible probe, the flexible probe 100 includes a spiral magnetizing coil 110 and a zigzag coil 120, the spiral magnetizing coil 110 is attached to the part to be measured, and the spiral magnetizing coil 110 is configured to generate an alternating magnetic field by loading an AC current; the zigzag coil 120 is arranged at a position between the spiral magnetizing coil 110 and the part to be measured, and the zigzag coil 120 is configured to generate a dynamic magnetic field by loading a pulse train current, wherein the flexible probe 100 generates magnetostrictive vibration based on the alternating magnetic field and the dynamic magnetic field, and excites an ultrasonic signal.

[0019] During implementation, a spiral magnetization coil 110 is used to replace a traditional permanent magnet to generate a bias magnetic field. Both the spiral magnetization coil 110 and the zigzag coil 120 can be flexibly bent, thereby effectively fitting the surface of the part to be tested, and are particularly suitable for curved surface detection of the part to be tested, effectively reducing the volume of the probe while achieving flexible detection. The spiral magnetization coil 110 is used to provide an alternating magnetic field, and the vibration influencing factors of the magnetostrictive force are jointly determined by the alternating magnetic field intensity, the dynamic magnetic field intensity and the magnetostriction amount, so that effective excitation of ultrasound can be achieved at a relatively low current, and the signal-to-noise ratio is relatively high.

[0020] It can be understood that the above-mentioned parts to be tested are ferromagnetic parts, including ferromagnetic plates and the like.

[0021] The spiral magnetization coil 110 in this embodiment is attached to the part to be tested, and the spiral magnetization coil 110 is configured to generate an alternating magnetic field by loading an alternating current.

[0022] In one embodiment, the flexible probe 100 further includes a first flexible housing, which is cylindrical, and the spiral magnetization coil 110 is wound on the first flexible housing, and the first flexible housing is configured to be deformed under the action of an external force so as to be attached to the surface of the part to be measured. The spiral magnetization coil 110 is an enameled wire, which is wound on the outer surface of the first flexible housing to form a spiral structure, and can be conformally attached according to the surface contour of the part to be measured.

[0023] The frequency of the alternating current loaded in the spiral magnetizing coil 110 is approximately between 1 kHz and 100 kHz.

[0024] The zigzag coil 120 in this embodiment is disposed between the spiral magnetization coil 110 and the part to be tested, and is configured to generate a dynamic magnetic field by loading a pulse train current. The zigzag coil 120 is a coil whose wire extends in a serpentine direction, which is a structure that can be imagined by those skilled in the art, and will not be described in detail here.

[0025] In one embodiment, the flexible probe 100 further includes a second flexible shell, which is in sheet form, and the meander coil 120 is built into the second flexible shell through FPC technology. The second flexible shell is configured to be deformable under external force so as to be attached to the surface of the part to be tested.

[0026] The frequency of the pulse train current loaded in the meander coil 120 is approximately between 100 kHz and 1 MHz.

[0027] To facilitate the control of the alternating current loaded into the spiral magnetizing coil 110 and the pulse train current loaded into the zigzag coil 120, in one embodiment, the flexible probe 100 further includes a clock module electrically connected to the spiral magnetizing coil 110 and the zigzag coil 120, and the clock module is configured to control the loading timing of the alternating current and the pulse train current.

[0028] The clock module includes a synchronization circuit and a gating circuit electrically connected to the spiral magnetization coil 110 and the zigzag coil 120. The synchronization circuit is used to control the excitation time of the alternating current and the pulse train current to be the same. The gating circuit controls the number of pulse trains of the pulse train current based on the frequencies of the alternating current and the pulse train current.

[0029] The SH mode ultrasonic wave generated based on the alternating magnetic field and the dynamic magnetic field can detect the surface defects of the part to be tested, and can also detect the internal defects of the part to be tested. The principle of generating the above ultrasonic wave is as follows: the zigzag coil 120 excites the dynamic magnetic field in the part to be tested, and the spiral magnetization coil 110 generates an alternating magnetic field in the part to be tested. The dynamic magnetic field and the alternating magnetic field interact based on the magnetostriction principle to generate particle vibration in the ferromagnetic material, thereby forming ultrasonic waves.

[0030] like Figure 1 As shown, when testing the board component M1, the meander coil 120 is in sheet shape and is spread flat on the surface of the board component to be tested, and the spiral magnetization coil 110 is arranged on the side of the meander coil 120 away from the board component to be tested.

[0031] like Figure 2 As shown, when testing the curved surface part M2, the meander coil 120 is first bent so that it can be attached to the curved surface of the part, and at the same time, the spiral magnetization coil 110 is squeezed so that it is close to the curved surface to form a curvature that matches it.

[0032] It can be understood that, according to the surface shape of the part to be tested, the spiral magnetization coil 110 and the meander coil 120 can be deformed into corresponding shapes, thereby achieving flexibility testing.

[0033] like Figure 3As shown, the present invention also provides a detection device 200 based on the AC magnetized magnetostrictive flexible probe 100, including the AC magnetized magnetostrictive flexible probe 100 as described above, and the detection device 200 also includes an AC excitation power supply 210, a pulse train excitation power supply 221 and a signal receiving module 222, the AC excitation power supply 210 is electrically connected to the spiral magnetization coil 110, and is used to load an AC current to the spiral magnetization coil 110, the pulse train excitation power supply 221 is electrically connected to the zigzag coil 120, and is used to load a pulse train current to the zigzag coil 120, and the signal receiving module 222 is electrically connected to the zigzag coil 120, and is used to receive the induced voltage signal generated by the zigzag coil 120.

[0034] like Figure 3 As shown, the present invention also provides a detection method based on the AC magnetized magnetostrictive flexible probe 100, which is applied to the detection device 200 based on the AC magnetized magnetostrictive flexible probe 100 as described above, comprising: Step S100, two flexible probes are spaced apart and attached to the surface of the part to be tested, wherein one of the flexible probes is an ultrasonic excitation probe and the other flexible probe is an ultrasonic receiving probe; Step S200: The AC excitation power supply loads AC current to the spiral magnetization coils in the ultrasonic excitation probe and the ultrasonic receiving probe, thereby generating an alternating positive and negative alternating magnetic field at two locations on the surface of the part to be tested; Step S300, the pulse train excitation power supply loads the pulse train current to the zigzag coil in the ultrasonic excitation probe, thereby generating a dynamic magnetic field in the part to be tested; Step S400, the alternating magnetic field and the dynamic magnetic field interact to generate magnetostrictive vibration on the surface of the part to be tested, and stimulate an ultrasonic signal; Step S500: The ultrasonic receiving probe receives the ultrasonic wave generated by the ultrasonic excitation probe and the ultrasonic wave reflected from the defect of the part to be tested, and an induced voltage signal is generated in the zigzag coil in the ultrasonic receiving probe; Step S600: The signal receiving module captures the induced voltage signal and analyzes and processes it to obtain a detection result.

[0035] In step S100, the ultrasonic excitation probe generates ultrasonic waves based on the magnetostriction principle, and the ultrasonic receiving probe generates electrical signals based on the inverse magnetostriction principle.

[0036] In step S200 to step S300 , the loading sequence of the AC excitation power supply 210 and the pulse train excitation power supply 221 is controlled by the clock module, wherein the clock module synchronously turns on the AC excitation power supply 210 and the pulse train excitation power supply 221 .

[0037] The loading sequence of the AC excitation power supply 210 and the pulse train excitation power supply 221 controlled by the clock module includes: The clock module captures the phase of the AC current, and when the AC current value starts to increase from zero, the synchronization circuit of the clock module sends a trigger signal to the pulse train excitation power supply 221; The gate circuit of the clock module is turned on, and the pulse train excitation power supply 221 generates a preset number of pulse train currents in the zigzag coil 120 in the ultrasonic excitation probe, thereby generating a dynamic magnetic field of a preset time width in the part to be tested.

[0038] In step S600, the signal receiving module 222 transmits the captured induced voltage signal to the oscilloscope 230. The pulse train excitation power supply 221 and the signal receiving module 222 can be integrated into the excitation / receiving module 220, and the excitation / receiving module 220 includes a signal output terminal 223 connected to the signal receiving module 222 and transmitted to the oscilloscope 230.

[0039] like Figure 1 As shown, in the embodiment of the present invention, a spiral magnetizing coil 110 is used to provide an alternating magnetic field, and a pulse train current is passed through the zigzag coil 120. The pulse train current is a sine function modulated by a Hanning window. The pulse train current generates a dynamic magnetic field in the part to be tested, which interacts with the alternating magnetic field to generate an oscillating magnetostrictive force along the Y direction, and generates an SH wave in the X direction.

[0040] At this time, the magnetostrictive force can be expressed by the following formula: ; in, Magnetostrictive force, is the piezomagnetic coefficient, is the magnetostriction, is the alternating magnetic field strength, is the dynamic magnetic field strength.

[0041] The above piezomagnetic coefficient is a constant value, and the vibration influencing factor of magnetostrictive force is determined by the alternating magnetic field intensity , dynamic magnetic field strength And magnetostriction Together, they determine that effective excitation of SH waves can be achieved at relatively low current magnetization with a high signal-to-noise ratio.

[0042] The magnetic induction intensity of the energized coil at a point P in space is approximately, ; in is the vacuum permeability, is the number of coil turns, Coil current, is the distance between the coil and the central axis, is the distance from point P to the center of the coil.

[0043] The alternating magnetic field strength generated by the spiral magnetizing coil at point P ,in, is the magnetic induction intensity of the spiral magnetized coil at point P, which can be obtained by the calculation formula of the energized coil mentioned above. Similarly, the magnetic field intensity of the zigzag coil at point P can be approximated as , The magnetic induction intensity of the zigzag coil at point P can be obtained by the calculation formula of the energized coil mentioned above.

[0044] like Figure 3 As shown, the detection principle of the system of the present invention is that the excitation / receiving device outputs a sine function modulated by a Hanning window to the zigzag coil 120, the AC power supply outputs AC power to the AC magnetizer, the excitation transducer generates a magnetostrictive force in the part to be tested based on the magnetostrictive principle to cause particle vibration, thereby generating SH waves, and the receiving transducer generates an electrical signal based on the inverse magnetostrictive principle and displays it on the oscilloscope 230.

[0045] like Figure 4 As shown, the present invention is based on Figure 3 The detection device 200 shown obtains the SH wave initial wave and direct wave experimental diagrams in a 1mm ferromagnetic 430 stainless steel plate, wherein the AC magnetizer is fed with AC power with an amplitude of 30A and a frequency of 8000Hz. Under relatively low current conditions, signal excitation and reception can be achieved, and a better signal-to-noise ratio can be obtained.

[0046] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An AC magnetized magnetostrictive flexible probe, characterized in that: Flexible probe includes: A spiral magnetizing coil is attached to the part to be tested, and is configured to generate an alternating magnetic field by applying an alternating current; a zigzag coil disposed between the spiral magnetizing coil and the part to be tested, the zigzag coil being configured to generate a dynamic magnetic field by loading a pulse train current; Wherein, the flexible probe generates magnetostrictive vibration based on the alternating magnetic field and the dynamic magnetic field, and excites an ultrasonic signal.

2. The AC magnetization magnetostrictive flexible probe according to claim 1, characterized in that: The flexible probe further comprises a first flexible shell, which is cylindrical in shape, the spiral magnetization coil is wound on the first flexible shell, and the first flexible shell is configured to be deformable under the action of external force so as to be attached to the surface of the part to be measured.

3. The AC magnetization magnetostrictive flexible probe according to claim 1, characterized in that: The flexible probe also includes a second flexible shell, which is in sheet form. The meander coil is built into the second flexible shell through the FPC process. The second flexible shell is configured to be deformable under external force so as to be attached to the surface of the part to be tested.

4. The AC magnetization magnetostrictive flexible probe according to claim 1, characterized in that: The flexible probe further comprises a clock module electrically connected to the spiral magnetization coil and the meandering coil, wherein the clock module is configured to control a loading timing of an alternating current and a pulse train current.

5. The AC magnetization magnetostrictive flexible probe according to claim 4, characterized in that: The clock module includes the synchronization circuit and the gate control circuit electrically connected to the spiral magnetization coil and the meander coil, the synchronization circuit is used to control the excitation time of the alternating current and the pulse train current to be the same, and the gate control circuit controls the number of pulse trains of the pulse train current based on the frequencies of the alternating current and the pulse train current.

6. A detection device based on AC magnetization magnetostrictive flexible probe, characterized in that: The detection device comprises the AC magnetized magnetostrictive flexible probe according to any one of claims 1 to 5, and further comprises: an AC excitation power supply, which is electrically connected to the spiral magnetization coil and is used to load an AC current to the spiral magnetization coil; a pulse train excitation power supply, which is electrically connected to the zigzag coil and is used to load a pulse train current to the zigzag coil; A signal receiving module is electrically connected to the zigzag coil and is used to receive the induced voltage signal generated by the zigzag coil.

7. A detection method based on AC magnetization magnetostrictive flexible probe, characterized in that: The detection device based on the AC magnetization magnetostrictive flexible probe as claimed in claim 6 comprises: Two flexible probes are arranged at intervals and are both attached to the surface of the part to be tested, wherein one of the flexible probes is an ultrasonic excitation probe and the other flexible probe is an ultrasonic receiving probe; The AC excitation power supply loads AC current to the spiral magnetization coils in the ultrasonic excitation probe and the ultrasonic receiving probe, thereby generating an alternating positive and negative alternating magnetic field at two locations on the surface of the part to be tested; The pulse train excitation power supply loads the pulse train current to the zigzag coil in the ultrasonic excitation probe, thereby generating a dynamic magnetic field in the part to be tested; The interaction between the alternating magnetic field and the dynamic magnetic field generates magnetostrictive vibration on the surface of the part to be tested and stimulates ultrasonic signals; The ultrasonic receiving probe receives the ultrasonic wave generated by the ultrasonic excitation probe and the ultrasonic wave reflected from the defect of the part to be tested, and an induced voltage signal is generated in the meandering coil in the ultrasonic receiving probe; The signal receiving module captures the induced voltage signal and analyzes and processes it to obtain the detection result.

8. The detection method based on AC magnetization magnetostrictive flexible probe according to claim 7 is characterized in that: The loading sequence of the AC excitation power supply and the pulse train excitation power supply is controlled by a clock module, wherein the clock module starts the AC excitation power supply and the pulse train excitation power supply synchronously.

9. The detection method based on AC magnetization magnetostrictive flexible probe according to claim 8, characterized in that: The method of controlling the loading timing of the AC excitation power supply and the pulse train excitation power supply by the clock module includes: The clock module captures the phase of the AC current, and when the AC current value increases from zero, the synchronization circuit of the clock module sends a trigger signal to the pulse train excitation power supply; The gate circuit of the clock module is turned on, and the pulse train excitation power supply generates a preset number of pulse train currents in the zigzag coil in the ultrasonic excitation probe, thereby generating a dynamic magnetic field with a preset time width in the part to be tested.

10. The detection method based on AC magnetization magnetostrictive flexible probe according to claim 7, characterized in that: The signal receiving module transmits the captured induced voltage signal to the oscilloscope.

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