Dynamic stress measurement system and method for giant magnetostrictive transducer

Abstract

The invention discloses a dynamic stress measurement system and method for a giant magnetostrictive transducer. Comprising a power supply circuit; the power supply circuit is connected with the giant magnetostrictive transducer, the giant magnetostrictive transducer comprises a vibrator and a shell, the vibrator is arranged in the shell, and the upper end and the lower end of the vibrator are connected with the shell; the upper end and the lower end of the vibrator are both provided with the measuring rods, and the vibrator is connected with the shell through the measuring rods; the first anti-magnetic field strain gauge comprises two first resistance-type strain gauges and a first insulating material film, the two first resistance-type strain gauges are respectively a test piece A and a test piece B, and the test piece A is bonded with the measuring rod; and the positive electrode wire and the negative electrode wire of the first anti-magnetic field strain gauge are respectively connected with an access channel of the dynamic strain gauge. And the actual stress change in the giant magnetostrictive transducer can be effectively measured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensor measurement, in particular to a dynamic stress measurement system and method of a giant magnetostrictive transducer. BACKGROUND

[0002] The giant magnetostrictive transducer is a transducing equipment taking a giant magnetostrictive rod as a core, mainly including a vibrator and a mechanical shell. The magnetostrictive strain of the giant magnetostrictive rod is very sensitive to stress, and is easily affected by dynamic stress (including pre-stress and variable stress), so the design stress is usually within a certain range to fully exert the performance of the rod. In order to detect whether the internal stress of the transducer after development deviates from the design value, the stress needs to be effectively measured. The deviation of the stress will cause the magnetostrictive strain of the rod to deviate from the linear region, resulting in the decline and nonlinear distortion of the output of the transducer. The dynamic change of the stress will cause complex coupling in the rod, which may change the response characteristics of the transducer, and excessive stress change may even cause the transducer to run unstable.

[0003] At present, the research on the stress of the transducer focuses on the material properties of the rod, mainly by building a test platform outside the transducer to measure the stress-magnetostrictive strain characteristics of the rod. Some scholars have designed new mechanical structures in the transducer to adjust the size of the pre-stress, but have not studied the measurement method of the dynamic stress. Limited by the small measurement space in the transducer and the interference brought by the alternating magnetic field and mechanical vibration, the conventional measurement method has the problems of difficult arrangement and low precision, and the induced voltage as the interference source has the same frequency as the dynamic stress of the transducer, which is difficult to eliminate by conventional methods such as magnetic shielding and filtering, so it restricts the development of the dynamic stress measurement technology of the transducer. Due to the above reasons, there is still a lack of effective means to measure the dynamic stress of the transducer. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a dynamic stress measurement system and method of a giant magnetostrictive transducer, which can effectively measure the actual stress change inside the giant magnetostrictive transducer to better monitor the working condition of the giant magnetostrictive transducer.

[0005] The present application also proposes a dynamic stress measurement method of a giant magnetostrictive transducer.

[0006] According to the dynamic stress measurement system of a giant magnetostrictive transducer provided by the present application, the power supply circuit, the giant magnetostrictive transducer, the stress measurement device, the signal processing device and the computer are connected in series. a power supply circuit; a giant magnetostrictive transducer, the power supply circuit is connected with the giant magnetostrictive transducer, the giant magnetostrictive transducer includes a vibrator and a shell, the vibrator is arranged in the shell, and the upper end and the lower end of the vibrator are connected with the shell; a measuring rod, the upper end and the lower end of the vibrator are provided with the measuring rod, and the measuring rod is connected with the shell; The first anti-magnetic field strain gauge comprises two first resistance strain gauges and a first insulating material film, the two first resistance strain gauges are arranged in the same direction and are overlapped, the first insulating material film is arranged between the two first resistance strain gauges, and edges of the two first resistance strain gauges are bonded with the first insulating material film, positive electrode lines or negative electrode lines of the same level of the two first resistance strain gauges are connected, and unconnected electrode lines are used as positive electrode lines and negative electrode lines of the same level of the first anti-magnetic field strain gauge, the two first resistance strain gauges are respectively test piece A and test piece B, and the test piece A is bonded with the measuring rod. The dynamic strain meter is connected with the access channels of the dynamic strain meter respectively, and is placed away from the giant magnetostrictive transducer to avoid the magnetic field generated by the giant magnetostrictive transducer from interfering with the dynamic strain meter.

[0007] The super magnetostrictive transducer dynamic stress measurement system according to the embodiment of the application has at least the following beneficial effects: 1. The measuring rod is added to the super magnetostrictive transducer as a component for conducting stress and magnetic flux, so that the stress of the vibrator in the narrow space of the coil can be converted into the deformation of the measuring rod which is easy to measure without affecting the operating performance of the super magnetostrictive transducer.

[0008] 2. The first anti-magnetic field strain gauge is made by the method of three-layer overlapping bonding of two strain gauges and an insulating layer and connection of positive electrodes or negative electrodes. The bonding area is the periphery of the sensitive grid of the resistance strain gauge, and test piece A and test piece B measure the strain value and interference value of the first anti-magnetic field strain gauge respectively, so that test piece B does not deform and is only used for offsetting the induced voltage, and finally the self-offsetting of the magnetic field interference is realized. The measurement circuit can distinguish the interference signal in the strain, the measurement accuracy of the system is optimized, the response speed of the measurement is fast, the real-time measurement of the dynamic stress can be realized, and the design and development of the super magnetostrictive transducer can be well tested.

[0009] In summary, the improved measurement circuit is used to effectively measure the dynamic stress inside the super magnetostrictive transducer. The improved measurement circuit has the performance of resisting the same frequency electromagnetic interference, and only ordinary resistance strain gauges and dynamic strain meters are needed to form the circuit, so that the construction cost of the whole measurement system is reduced, and the system uses double-layer test pieces to collect the strain and interference signals in real time, so that the measurement system can more accurately measure the actual stress change inside the transducer, and the operating conditions of the transducer can be better monitored.

[0010] According to some embodiments of the present application, the compensation system further comprises a compensation rod and two second diamagnetic field strain gauges arranged side by side on the compensation rod, the second diamagnetic field strain gauges comprising: two second resistive strain gauges arranged in the same direction and a second insulating material film arranged between the two second resistive strain gauges and bonding the edges of the two second resistive strain gauges with the second insulating material film, the positive electrode line or the negative electrode line of the two second resistive strain gauges being connected, the unconnected electrode line serving as the positive electrode line and the negative electrode line of the second diamagnetic field strain gauge, the two second resistive strain gauges being compensation member A and compensation member B respectively, and the compensation member A being bonded with the compensation rod; and the compensation rod being away from the giant magnetostrictive transducer. The positive electrode line and the negative electrode line of the second diamagnetic field strain gauge are connected with the access channel of the dynamic strain meter respectively.

[0011] According to some embodiments of the present application, the positive electrode line and the negative electrode line of the second diamagnetic field strain gauge are connected with the access channel of the dynamic strain meter respectively in the form of a twisted pair.

[0012] According to some embodiments of the present application, the positive electrode line and the negative electrode line of the first diamagnetic field strain gauge are connected with the access channel of the dynamic strain meter respectively in the form of a twisted pair, and an additional twisted pair can be externally connected if the length of the twisted pair is not enough.

[0013] According to some embodiments of the present application, a matching capacitor plate is further connected in series on the power supply circuit.

[0014] According to the second aspect of the present application, a dynamic stress measurement method of a giant magnetostrictive transducer is provided, comprising: The dynamic stress measurement system of the giant magnetostrictive transducer is built, the shell is deformed by using an extrusion device to assemble the vibrator into the shell. After the assembly of the vibrator is completed, the prestress of the giant magnetostrictive transducer is obtained ； The giant magnetostrictive transducer is soft-fixed. The test parameters of the dynamic strain meter are set. The power supply circuit applies an alternating current excitation to the giant magnetostrictive transducer, and the total strain is measured and obtained by the dynamic strain meter and interference , the dynamic strain is obtained , and the calculation formula is as follows: based on the dynamic strain , Young's modulus of the measuring rod and the pre-stress , the dynamic stress in the giant magnetostrictive transducer is obtained , and the calculation formula is as follows: .

[0015] The super magnetostrictive transducer dynamic stress measurement method according to the embodiments of the present application has at least the following beneficial effects: the present application uses an improved measurement circuit to effectively measure the internal dynamic stress of the transducer. The improved measurement circuit has the performance of resisting the same frequency electromagnetic interference, and only ordinary resistance strain gauges and dynamic strain gauges are needed to form the circuit, thereby reducing the construction cost of the entire measurement system, and the system uses double-layer test pieces to collect strain and interference signals in real time, so that the established measurement system can more effectively measure the actual stress change inside the transducer and better monitor the running condition of the transducer.

[0016] According to some embodiments of the present application, during the assembly process of the vibrator, the pre-stress of the giant magnetostrictive transducer is obtained , including: releasing the pressure of the extrusion device, measuring the strain of the giant magnetostrictive transducer by the dynamic strain gauge until the pressure is 0 and the strain value is stable, obtaining the change of the strain value during the entire pressure relief process, and calculating the value of the pre-stress by the following formula: wherein, is the pre-stress of the giant magnetostrictive transducer during the assembly process of the vibrator, is the strain value measured by the dynamic strain gauge during the assembly process, is Young's modulus of the measuring rod; According to the value change during the assembly process , the initial stress value of and the stable stress value of are obtained , and the pre-stress of the vibrator after the assembly is completed is obtained by the following formula : .

[0017] According to some embodiments of the present application, the test parameters measured by the dynamic strain gauge are set to include: the bridge form of the bridge measurement circuit in the dynamic strain gauge is set to be a half-bridge one-to-one compensation mode; In the dynamic strain gauge, the bridge equivalent strain gauge resistance value parameters in the bridge measurement circuit are set according to the following formula: wherein, the bridge equivalent strain gauge resistance value in the bridge measurement circuit, the resistance value of a single first resistive strain gauge or second resistive strain gauge, the resistance value of a single wire in the twisted pair, The strain gauge sensitivity coefficient equivalent to the bridge in the bridge measurement circuit is set according to the following formula : wherein, the Poisson's ratio of the sensitive grid of the first resistive strain gauge or the second resistive strain gauge, the piezoresistive coefficient of the metal material in the sensitive grid of the first resistive strain gauge or the second resistive strain gauge, the Young's modulus of the metal material in the sensitive grid of the first resistive strain gauge or the second resistive strain gauge; or The strain gauge equivalent sensitivity coefficient in the bridge measurement circuit is set according to the following formula : wherein, the sensitivity coefficient of the first resistive strain gauge or the second resistive strain gauge.

[0018] According to some embodiments of the present application, the total strain and the interference measured and obtained by the dynamic strain gauge include: Two of the access channels are provided in the dynamic strain gauge, which are channel 1 and channel 2 respectively; The test piece A and the compensation piece A are connected to the measurement port and the compensation port of the channel 1; The test piece B and the compensation piece B are connected to the measurement port and the compensation port of the channel 2; In the test interface of the dynamic strain gauge, channel 1 is selected as the signal channel, the strain signal of the measurement rod is collected through the test piece A, and it is converted into the change value of the resistance of the test piece A ; The dynamic output voltage of the bridge measurement circuit in the dynamic strain gauge is set according to the following formula: wherein, the output voltage of the bridge measurement circuit, a direct current voltage provided for the dynamic strain gauge to the bridge measurement circuit; acquiring the output voltage of the bridge measurement circuit by the dynamic strain gauge calculating the dynamic strain of the measuring rod according to the analog output value displayed by the dynamic strain gauge , as follows: wherein, the analog output displayed by the dynamic strain gauge, the amplification factor of the amplifier in the dynamic strain gauge, and , the sensitivity coefficient of the first or second resistive strain gauge; the dynamic strain of the test piece A is obtained according to the above steps , containing the strain of the measuring rod and the interference of the strain gauge; Channel 2 is used as a signal channel, and the dynamic strain of the test piece B is calculated by the same method , containing only the interference of the test piece B; the real dynamic strain of the measuring rod is calculated by the following formula: .

[0019] According to some embodiments of the present application, the soft fixing of the giant magnetostrictive transducer comprises: The giant magnetostrictive transducer is suspended in the air by a soft rope, and the lower end of the giant magnetostrictive transducer is fixed vertically to the ground by a soft rope.

[0020] Additional aspects and advantages of the present application will be given in part in the following description, part will become apparent from the following description, or will be understood by those skilled in the art through practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0021] The present application will be further described below in conjunction with the drawings and examples, wherein: Figure 1 It is a structural schematic diagram of the giant magnetostrictive transducer dynamic stress measurement system in the embodiment of the present application; Figure 2 It is a schematic diagram of the manufacturing method of the first anti-magnetic field strain gauge in the embodiment of the present application; Figure 3 It is a schematic diagram of the transducer arrangement when measuring dynamic stress in the embodiment of the present application; Figure 4 It is a step flow chart of the giant magnetostrictive transducer dynamic stress measurement method in the embodiment of the present application; Figure 5 A structure schematic diagram of a half-bridge one-to-one compensation circuit in an embodiment of the present application; Figure 6 A prestress change graph in a transducer assembly process in an embodiment of the present application; Figure 7 A dynamic stress waveform graph measured under the condition of a current amplitude of 8A and an excitation frequency of 300Hz in an embodiment of the present application; Figure 8 A dynamic stress waveform graph measured under the condition of a current amplitude of 8A and an excitation frequency of 400Hz in an embodiment of the present application; Figure 9 A dynamic stress waveform graph measured under the condition of a current amplitude of 8A and an excitation frequency of 500Hz in an embodiment of the present application.

[0022] Reference signs: Vibrator 100; shell 200; soft rope 300; first diamagnetic field strain gauge 400; twisted pair 500; measurement rod 600. DETAILED DESCRIPTION

[0023] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary, only for explaining the present application, and cannot be understood as a limitation of the present application.

[0024] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, etc. is based on the orientation or position relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and cannot be understood as indicating or implying that the system or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0025] In the description of the present application, multiple refers to two or more. If there is a description of first, second, only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0026] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0027] Reference Figures 1 to 3 As shown in the drawings, the dynamic stress measurement system of the magnetostrictive transducer of the present application comprises: Power supply circuit; The super magnetostrictive transducer is connected with the power supply circuit, and the super magnetostrictive transducer comprises a vibrator 100 and a shell 200, the vibrator 100 is arranged in the shell 200, and the upper end and the lower end of the vibrator 100 are connected with the shell 200; The upper end and the lower end of the vibrator 100 are each provided with a measuring rod 600, and the measuring rod 600 is connected with the shell; The first anti-magnetic field strain gauge 400 comprises two first resistance strain gauges and a first insulating material film, the two first resistance strain gauges are arranged in the same direction and overlap each other, the first insulating material film is arranged between the two first resistance strain gauges, and the edges of the two first resistance strain gauges are bonded to the first insulating material film, the positive electrode lines or the negative electrode lines of the two first resistance strain gauges are connected, and the electrode lines not connected are used as the positive electrode lines and the negative electrode lines of the first anti-magnetic field strain gauge, the two first resistance strain gauges are respectively a test piece A and a test piece B, and the test piece A is bonded to the measuring rod 600; The dynamic strain meter is placed at a position far away from the super magnetostrictive transducer, so as to avoid magnetic field interference on the dynamic strain meter.

[0028] In the embodiment, the power supply circuit adopts an alternating current power supply, which is used to apply an alternating current excitation to the super magnetostrictive transducer, and the frequency and the amplitude of the excitation can be adjusted, and in the embodiment, 380V commercial power is specifically adopted.

[0029] The super magnetostrictive transducer is used as a measured object of dynamic stress, and is mainly composed of the vibrator 100 and the shell 200, and the dynamic stress is the real-time stress borne by the vibrator 100.

[0030] It should be noted that the measuring rod 600 has high magnetic permeability and good mechanical response speed, is used to convert the dynamic stress of the super magnetostrictive transducer into deformation and realize conduction of a magnetic loop. Common aluminum rods, copper rods, silver rods and gold rods cannot meet the requirements, but some iron-nickel alloys can be used as substitutes. In the embodiment of the application, the measuring rod 600 adopts a soft iron rod, and the soft iron rod has high magnetic permeability and good mechanical response speed, and has low price and low cost. The subsequent embodiments are described by taking the soft iron rod as the measuring rod 600.

[0031] Reference Figure 2In the embodiment, two first resistance strain gauges of the same type are selected as the first anti-magnetic field strain gauge. The sensitive grid width of the first resistance strain gauges needs to be less than 1 / 10 of the diameter of the soft iron rod to ensure that the bending angle of the sensitive grid on the side of the soft iron rod is not too large. The two first resistance strain gauges are placed with the bases downward and overlapping, and the sensitive grids of the two first resistance strain gauges are aligned in the vertical direction. A first insulating material film is placed between the two first resistance strain gauges to isolate static electricity generated by the friction of the first resistance strain gauge shell.

[0032] Reference Figure 2 In the embodiment, a circle outside the sensitive grid of the first resistance strain gauge is divided into an adhesive area Q. The two strain gauges are coated with glue in the area Q and are bonded with the first insulating material film, and no obvious gap is ensured between the three. This makes the two first resistance strain gauges at the same spatial measurement point (the same interference), and the test piece B does not deform with the test piece A bonded with the measurement rod 600. At the same time, the dynamic deformation of the test piece A basically does not affect the resistance value of the test piece B.

[0033] The same potential ends of the two first resistance strain gauges are connected, that is, the positive electrode lines of the two first resistance strain gauges are connected, or the negative electrode lines are connected. The approximately same induced interference voltages of the two first resistance strain gauges are counteracted in reverse.

[0034] In the embodiment, the positive electrode lines of the two first resistance strain gauges are connected as the same potential ends. Specifically, the positive electrode lines of the two first resistance strain gauges are cut to reserve only the welding length, and the two positive electrode lines are welded. Each of the two first resistance strain gauges will have one negative electrode line, and the two negative electrode lines are used as the lead-out lines of the whole, that is, as the positive and negative electrodes of the first anti-magnetic field strain gauge. Because the induced voltages of the two first resistance strain gauges caused by the magnetic field interference are basically the same, and the voltage directions are also the same. After the positive electrode lines of the two first resistance strain gauges are connected, the two induced voltages can basically automatically counteract each other.

[0035] The positive and negative electrode lines of the first anti-magnetic field strain gauge are connected to the access channels of the dynamic strain meter to measure the dynamic strain of the measurement rod 600 over time.

[0036] Further, the two negative electrode lines used as the lead-out lines are twisted into a twisted pair 500, or an external twisted pair is connected to lengthen the length of the twisted pair 500, and then wrapped with solid glue to make it fixed. Twisting the twisted pair 500 can realize the alternating self-counteraction of the two lead-out lines in the magnetic field interference environment, thereby reducing the interference factors.

[0037] The bonding method between the first anti-magnetic field strain gauge and the soft iron rod is as follows: 1) Through the simulation calculation of the spatial numerical distribution of the magnetic field in the soft iron rod, the magnetic field strength distribution rule of "small in the middle and large at both ends" is obtained, a point on the outside of the giant magnetostrictive transducer is selected at the middle segment of the side surface of the soft iron rod as a dynamic stress measurement point, and the measurement point and the surrounding area are polished and cleaned with sandpaper; 2) Since the dynamic stress of the giant magnetostrictive transducer is the same frequency as the alternating magnetic field, it is impossible to eliminate interference through filtering and magnetic shielding means, so a control group simulation interference is set to realize self-cancellation of interference. Test piece A is bonded at the measurement point, which is used to measure the total strain of the soft iron rod (including interference), and the glue is dried to make it set; test piece B is placed on test piece A in alignment, and the two are isolated by an insulating film, test piece B is used to collect interference signals (mainly the induced voltage caused by the interference of the alternating magnetic field on the sensitive grid and the lead wire when the giant magnetostrictive transducer vibrates), and the interference is cancelled with test piece A. Otherwise, the true strain will be covered by the interference signal (the amplitude of the interference signal is greater than the strain value).

[0038] In some embodiments of the present application, a compensation system is further included, and the compensation system comprises a compensation rod and two second anti-magnetic field strain gauges arranged side by side on the compensation rod, and the second anti-magnetic field strain gauge comprises: two second resistance strain gauges and a second insulating film, the two second resistance strain gauges are arranged in the same direction and overlap each other, the second insulating film is arranged between the two second resistance strain gauges, and the edges of the two second resistance strain gauges are bonded with the second insulating film, the positive electrode line or the negative electrode line of the two second resistance strain gauges is connected, and the unconnected electrode line serves as the positive electrode line and the negative electrode line of the second anti-magnetic field strain gauge, the two second resistance strain gauges are compensation piece A and compensation piece B respectively, and the compensation piece A is bonded with the compensation rod; The positive electrode line and the negative electrode line of the second anti-magnetic field strain gauge are connected with the access channel of the dynamic strain meter respectively.

[0039] In the present embodiment, another soft iron rod is taken as a compensation rod, a region on the side surface of the compensation rod is polished and cleaned, and two second anti-magnetic field strain gauges are pasted at the region. Figure 2 The manufacturing method of the second anti-magnetic field strain gauge is the same as that of the first anti-magnetic field strain gauge, which will not be described herein. The two second anti-magnetic field strain gauges are used for temperature compensation and are arranged in correspondence with the circuits in which the two first anti-magnetic field strain gauges are arranged, so as to form a one-to-one compensation circuit.

[0040] By arranging the compensation rod, the measurement error caused by the change of the environmental temperature can be compensated. The lead wires of the second anti-magnetic field strain gauge are twisted into a twisted pair and fixed with a solid glue to eliminate the magnetic field interference.

[0041] In some embodiments of the present application, a matching capacitor plate is further included, and the matching capacitor plate is connected in series on the power supply circuit.

[0042] The matching capacitor plate is used to balance the inductive impedance of the giant magnetostrictive transducer. Different matching capacitor values ​​are required for different operating frequencies to match the changes in the transducer's inductive impedance, ensuring that the load power does not exceed the power supply limit. The AC power supply is connected in series with both the matching capacitor plate and the giant magnetostrictive transducer to form the power supply circuit for the high-voltage side.

[0043] In some embodiments of the present invention, a PC host computer is also included. The dynamic strain gauge is connected to the PC host computer, the dynamic strain gauge measurement software is loaded, the output voltage of the dynamic strain gauge is read, and it is converted into a strain signal.

[0044] refer to Figure 4 The present invention also discloses a method for measuring dynamic stress in a giant magnetostrictive transducer, comprising: The above-described embodiment of the super magnetostrictive transducer dynamic stress measurement system is constructed by using an extrusion device to extrude the housing 200, thereby deforming the housing 200 and assembling the oscillator 100 into the housing 200. After the oscillator 100 is assembled, the prestress of the supermagnetostrictive transducer is obtained. ； Soft-fixed super magnetostrictive transducer; The test parameters for dynamic strain gauge measurement are set, the power supply circuit applies AC current excitation to the giant magnetostrictive transducer, and the total strain is measured and obtained by the dynamic strain gauge. and interference To obtain dynamic strain The calculation formula is as follows: Based on dynamic strain Young's modulus of measuring rod 600 and prestressed To obtain the dynamic stress in the supermagnetostrictive transducer The calculation formula is as follows: .

[0045] In this embodiment, the housing 200 is deformed by extrusion equipment, thereby assembling the oscillator 100 into the housing 200. Specifically, a press is used as the extrusion equipment. The oscillator 100 is then assembled into the housing 200 of the giant magnetostrictive transducer. Test piece A is used to measure the real-time strain value of the soft iron rod during the assembly process, and the strain of the soft iron rod is recorded on a dynamic strain gauge. The curve is used to calculate the prestress of the giant magnetostrictive transducer based on the strain change value. .

[0046] In addition, the compensation rod and the dynamic strain gauge are placed away from the giant magnetostrictive transducer and are spaced apart from the giant magnetostrictive transducer by more than 5 m. It is found that the magnetic field generated by the coil at a distance of more than 5 m from the giant magnetostrictive transducer is very weak, which can ensure that the alternating magnetic field does not interfere with the dynamic strain gauge and the compensation member.

[0047] When the lead wire is introduced, the 90° bent twisted pair wire is used, and the position of the bending point is close to the welding point of the strain gauge and the twisted pair wire, so that the twisted pair wire is suspended and does not contact the soft iron rod, so as to reduce the wire vibration of the twisted pair wire. The lead wire at the bending point is adhered to the soft iron rod with glue, and is wrapped with solid glue, so as to enhance the toughness of the twisted pair lead-out wire.

[0048] The positions of 1 / 3 and 2 / 3 of the twisted pair wire are clamped by the metal clamp table, and the rear part is suspended in the air to avoid the twisted pair wire from touching any vibrating object (including the soft iron rod, the vibrator, the coil and other transducer components); the lead-out wire (set as wire segment Y) between the first clamp table and the bending point is wrapped with solid soft glue for protection, both ends of the wire segment Y are wrapped with metal sleeves to ensure that it is not bent (to avoid touching the vibrating object), and the middle segment of the wire segment Y is kept in a natural state of hanging down to minimize the mechanical vibration transmitted to the twisted pair wire during the operation of the transducer, so as to protect the twisted pair wire from being broken. The twisted pair wire connected with the test member is arranged in a straight line along the vertical direction of the side surface of the transducer to avoid contacting the giant magnetostrictive transducer to cause greater vibration (the interference is enhanced), and the tail end is connected to the dynamic strain gauge; the twisted pair wire connected with the compensation member is also connected to the dynamic strain gauge; the lengths of all the twisted pair wires are kept consistent (the resistances are the same) to avoid the resistances of the first anti-magnetic field strain gauge and the second anti-magnetic field strain gauge being different, which affects the balance of the electric bridge, so that the output voltage deviates from the expected value, resulting in reduced measurement accuracy.

[0049] In the embodiment, the giant magnetostrictive transducer is fixed in a soft fixed manner. The giant magnetostrictive transducer works in a relative fixed position in the air to avoid touching other objects when vibrating. Specifically, the upper end of the giant magnetostrictive transducer is suspended in the air by a soft rope 300, the lower end of the giant magnetostrictive transducer is vertically fixed to the ground by a soft rope 300, and the lead-out wires (twisted pair wires) of the test members A and B are introduced from the side surface of the giant magnetostrictive transducer. The end of the twisted pair shield wire of the test member A is connected to channel 1 of the dynamic strain gauge, and the lead-out wire of the compensation member A is connected to the compensation port of channel 1 through the twisted pair wire. Then, the test member B and its compensation member B are connected to channel 2 of the dynamic strain gauge in the same way. The shielding layers of all the twisted pair wires are grounded through the lead wire to guide the induced charge on the shielding layer to the ground, so as to realize high-frequency magnetic shielding of the shielding layer.

[0050] An alternating current source is used to apply a current excitation of a certain frequency and amplitude to the giant magnetostrictive transducer. In the example, the current amplitude is uniformly 8 A, and the excitation frequencies are 300 Hz, 400 Hz and 500 Hz respectively.

[0051] Select channel 1 as the strain signal channel in the test interface of the dynamic strain meter, and calculate the total dynamic strain of the soft iron rod based on the analog output voltage of channel 1 The formula is as follows: Wherein, is the analog output voltage of the dynamic strain meter, is the amplification multiple of the analog circuit in the dynamic strain meter, is the direct current voltage provided by the dynamic strain meter to the bridge circuit, is the equivalent sensitivity coefficient of the test piece.

[0052] Select channel 2 as the interference signal channel in the test interface of the dynamic strain meter, and calculate the equivalent strain of the interference based on the analog output voltage of channel 2 The formula is as follows: Then, the real dynamic strain of the soft iron rod is calculated by the following formula: Based on the dynamic strain and the mechanical parameters of the soft iron rod, the real dynamic stress in the giant magnetostrictive transducer is calculated by the dynamic strain meter, and the specific calculation formula is as follows: Wherein, is the dynamic stress of the transducer, is the Young's modulus of the soft iron rod.

[0053] The application improves the strain gauge setting method under alternating magnetic field, adopts the magnetic field resistant strain gauge manufacturing method of resistance strain gauge edge overlapping bonding and same pole welding, so that the first magnetic field resistant strain gauge and the second magnetic field resistant strain gauge can self-cancel the induced voltage of the sensitive grid in the alternating magnetic field, then the half-bridge one-to-one compensation circuit is improved for the magnetic field resistant strain gauge, and the long twisted pair shielded wire of the first end fixed clamping type is adopted to remotely access the dynamic strain meter, which can greatly weaken the magnetic field interference caused by wire vibration and the magnetic field interference on the strain meter, so that the dynamic stress measurement of the system is more accurate.

[0054] ​​​In the dynamic stress measurement method of the giant magnetostrictive transducer, the double-layer first anti-magnetic field strain gauge is used as the test piece, and the strain value and the interference value of the first anti-magnetic field strain gauge are measured, so that the measurement circuit can distinguish the interference signal in the strain, the measurement accuracy of the system is further optimized, the response speed of the measurement is fast, the real-time measurement of the dynamic stress can be realized, and the design and development of the transducer are better tested.

[0055] Compared with the prior art, the improved measurement circuit is used for effectively measuring the dynamic stress inside the transducer. The improved measurement circuit has the performance of resisting the same frequency electromagnetic interference, and only ordinary resistance strain gauges and dynamic strain gauges are needed to form the circuit, so that the construction cost of the whole measurement system is reduced, and the system adopts double-layer test pieces to collect the strain and interference signals in real time, so that the measurement system can more effectively measure the actual dynamic stress change inside the transducer, and the running condition of the transducer can be better monitored.

[0056] In some embodiments of the present application, after the assembly of the vibrator 100 is completed, the prestress of the giant magnetostrictive transducer is obtained including: The pressure of the extrusion device is released until the pressure is 0 and the strain value is stable, the change of the strain value in the whole pressure relief process is obtained, and the value of the prestress is calculated by using the following formula: Among them, is the prestress of the giant magnetostrictive transducer in the assembly process of the vibrator 100, is the strain value measured by the dynamic strain meter in the assembly process, is the Young's modulus of the measuring rod 600; Reference Figure 6 As shown in the figure, according to the change of the value of the strain value in the assembly process , the initial stress value and the stable stress value of the vibrator 100 are obtained , and the prestress of the vibrator 100 after the assembly is completed is obtained by the following formula : .

[0057] In some embodiments of the present application, the test parameters measured by the dynamic strain meter include: The bridge form of the bridge measurement circuit in the dynamic strain meter is a half-bridge one-to-one compensation mode; The dynamic strain meter includes two access channels, which are channel 1 and channel 2; The test piece A and the compensation piece A are connected to the measurement port and the compensation port of the channel 1; The test piece B and the compensation piece B are connected to the measuring port and the compensation port of the channel 2; In the dynamic strain meter, the bridge resistance value parameter of the bridge equivalent in the bridge measurement circuit is set according to the following formula: wherein, the bridge resistance value of the bridge equivalent in the bridge measurement circuit, the resistance value of the single first resistive strain gauge or the second resistive strain gauge, the resistance value of a single wire in the twisted pair wire 500; The strain gauge sensitivity coefficient of the bridge equivalent in the bridge measurement circuit is set according to the following formula : wherein, the Poisson's ratio of the sensitive grid of the first resistive strain gauge or the second resistive strain gauge, the piezoresistive coefficient of the metal material in the sensitive grid of the first resistive strain gauge or the second resistive strain gauge, the Young's modulus of the metal material in the sensitive grid of the first resistive strain gauge or the second resistive strain gauge; or The strain gauge sensitivity coefficient of the bridge equivalent in the bridge measurement circuit is set according to the following formula : wherein, the sensitivity coefficient of the first resistive strain gauge or the second resistive strain gauge.

[0058] Referring to Figure 5 , a half-bridge one-to-one compensation circuit is adopted, the circuit has fewer devices and has a temperature compensation effect, and then the measurement parameters of the circuit are set in the dynamic strain meter.

[0059] The soft iron rod with the compensation piece is placed away from the giant magnetostrictive transducer in the dynamic strain meter, the lead-out wire of the compensation piece is fixed by a metal clamp table and glue, and the method is consistent with that of the test piece, so as to avoid the lead-out wire from touching the vibrating object.

[0060] In some embodiments of the present application, the total strain and the interference are measured and obtained by the dynamic strain meter, and the total strain and the interference include: Two access channels are provided in the dynamic strain meter, which are channel 1 and channel 2; The test piece A and the compensation piece A are connected to the measuring port and the compensation port of the channel 1; The test piece B and the compensation piece B are connected to the measuring port and the compensation port of the channel 2;In the test interface of the dynamic strain meter, channel 1 is selected as a signal channel, the strain signal of the measuring rod is collected through the test piece A, and the strain signal is converted into the change value of the resistance of the test piece A ; In the dynamic strain meter, the dynamic output voltage of the bridge measurement circuit is set by the following formula: wherein, is the output voltage of the bridge measurement circuit, is the direct current voltage provided by the dynamic strain meter to the bridge measurement circuit; The output voltage of the bridge measurement circuit is collected by the dynamic strain meter , and the dynamic strain of the measuring rod 600 is calculated according to the analog output value displayed by the dynamic strain meter , and the formula is as follows: wherein, is the analog output displayed by the dynamic strain meter, is the amplification multiple of the amplifier in the dynamic strain meter, is the sensitivity coefficient of the first or second resistance strain gauge; The dynamic strain of the test piece A is obtained according to the above steps , including the strain of the measuring rod and the interference of the strain gauge; Channel 2 is selected as a signal channel, and the dynamic strain of the test piece B is calculated by the same method , only including the interference of the strain gauge; The real dynamic strain of the measuring rod is calculated by the following formula: .

[0061] Based on the dynamic strain and the material properties, the real dynamic stress is inversely calculated, and the specific formula is as follows: wherein, is the dynamic stress of the giant magnetostrictive transducer, is the Young's modulus of the soft iron rod.

[0062] Referring to Figures 7 to 9 , the dynamic stress waveform diagram measured under the condition that the current amplitude is uniformly 8A and the excitation frequency is 300Hz, 400Hz and 500Hz.

[0063] In some embodiments of the present application, the soft fixed giant magnetostrictive transducer comprises: The giant magnetostrictive transducer is hung in the air by the soft rope 300, and the lower end of the giant magnetostrictive transducer is vertically fixed to the ground by the soft rope 300.

[0064] The above describes the embodiments of the present application in detail in combination with the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present application.

Claims

1. A dynamic stress measurement system for a giant magnetostrictive transducer, characterized in that, include: Power supply circuit; A giant magnetostrictive transducer, wherein the power supply circuit is connected to the giant magnetostrictive transducer, the giant magnetostrictive transducer includes an oscillator and a housing, the oscillator is disposed inside the housing, and the upper end and lower end of the oscillator are connected to the housing; Measuring rods are provided at both the upper and lower ends of the vibrator and are connected to the housing through the measuring rods; The first magnetic field resistance strain gauge includes two first resistive strain gauges and a first insulating material film. The two first resistive strain gauges are overlapped in the same direction. The first insulating material film is disposed between the two first resistive strain gauges, and the edges of the two first resistive strain gauges are bonded to the first insulating material film. The positive or negative electrode lines of the same level of the two first resistive strain gauges are connected. The unconnected electrode lines serve as the positive and negative electrode lines of the first magnetic field resistance strain gauge. The two first magnetic field resistance strain gauges are test piece A and test piece B, respectively. Test piece A is bonded to the measuring rod. The dynamic strain gauge has its positive and negative electrode lines connected to the access channel of the two first anti-magnetic field strain gauges, and the dynamic strain gauge is placed at a position away from the super magnetostrictive transducer.

2. The dynamic stress measurement system for a giant magnetostrictive transducer according to claim 1, characterized in that: It also includes a compensation system, which includes a compensation rod and two second anti-magnetic field strain gauges, the two second anti-magnetic field strain gauges being arranged side by side on the compensation rod; The second anti-magnetic field strain gauge includes two second resistive strain gauges and a second insulating material film. The two second resistive strain gauges are overlapped in the same direction. The second insulating material film is disposed between the two second resistive strain gauges, and the edges of the two second resistive strain gauges are bonded to the second insulating material film. The positive or negative electrode lines of the same polarity of the two second resistive strain gauges are connected. The unconnected electrode lines serve as the positive and negative electrode lines of the second anti-magnetic field strain gauge. The two second resistive strain gauges are compensation element A and compensation element B, respectively. Compensation element A is bonded to the compensation rod. The compensation rod is located away from the supermagnetic-strictive transducer. The positive and negative electrode lines of the second anti-magnetic strain gauge are respectively connected to the access channel of the dynamic strain gauge.

3. The dynamic stress measurement system for a giant magnetostrictive transducer according to claim 2, characterized in that: The positive and negative electrode wires of the second anti-magnetic field strain gauge are twisted pairs and connected to the access channel of the dynamic strain gauge.

4. The dynamic stress measurement system for a giant magnetostrictive transducer according to claim 1, characterized in that: The positive and negative electrode wires of the first anti-magnetic field strain gauge are twisted pairs and connected to the access channel of the dynamic strain gauge.

5. The dynamic stress measurement system for a giant magnetostrictive transducer according to claim 1, characterized in that: It also includes a matching capacitor board, which is connected in series in the power supply circuit.

6. A method for measuring dynamic stress in a giant magnetostrictive transducer, characterized in that, include: A dynamic stress measurement system for a giant magnetostrictive transducer as described in any one of claims 1 to 5 is constructed, and the housing is deformed by extrusion equipment to assemble the oscillator into the housing; After the oscillator is assembled, the prestress of the supermagnetostrictive transducer is obtained. ； The super magnetostrictive transducer is softly fixed; Set the test parameters measured by the dynamic strain gauge; The power supply circuit applies an alternating current excitation to the supermagnetostrictive transducer, and the total strain is measured and obtained by the dynamic strain gauge. and interference To obtain dynamic strain The calculation formula is as follows: Based on the dynamic strain The Young's modulus of the measuring rod and the prestress The dynamic stress in the supermagnetostrictive transducer is obtained. The calculation formula is as follows: 。 7. The method for measuring dynamic stress in a giant magnetostrictive transducer according to claim 6, characterized in that: After the oscillator is assembled, the prestress of the supermagnetostrictive transducer is obtained. include: Release the pressure from the extrusion device until the pressure is 0 and the strain value stabilizes. Obtain the change in the strain value throughout the entire depressurization process, and calculate the prestress value using the following formula: in, The prestress of the giant magnetostrictive transducer during the assembly process of the oscillator. The strain values ​​measured by the dynamic strain gauge during the assembly process. The Young's modulus of the measuring rod; According to the assembly process Numerical changes, acquisition initial stress value and the stress value after stabilization The prestress of the oscillator after assembly is obtained by the following formula. : 。 8. The method for measuring dynamic stress in a giant magnetostrictive transducer according to claim 6, characterized in that: Setting the test parameters measured by the dynamic strain gauge includes: The bridge circuit of the Wheatstone bridge measurement circuit in the dynamic strain gauge is configured as a half-bridge one-to-one compensation method. The equivalent strain gauge resistance value of the bridge circuit in the dynamic strain gauge is set according to the following formula: in, The value is the equivalent strain gauge resistance of the bridge circuit in the aforementioned bridge measurement circuit. The resistance value of a single first or second resistive strain gauge. This represents the resistance value of a single wire in a twisted pair cable. Set the strain gauge sensitivity coefficient of the bridge equivalent in the bridge measurement circuit according to the following formula. parameter: in, The Poisson's ratio of the sensing grid of the first resistive strain gauge or the second resistive strain gauge. The piezoresistive coefficient of the metallic material in the sensing grid of the first or second resistive strain gauge is given. The Young's modulus of the metallic material in the sensing grid of the first or second resistive strain gauge; or Set the equivalent sensitivity coefficient of the strain gauge in the bridge measurement circuit according to the following formula. : in, The sensitivity coefficient is the first or the second resistive strain gauge.

9. The method for measuring dynamic stress in a giant magnetostrictive transducer according to claim 8, characterized in that: The total strain is measured and obtained using the dynamic strain gauge. and interference include: The dynamic strain gauge is equipped with two access channels, namely channel 1 and channel 2. Connect the test piece A and the compensation piece A to the measurement port and compensation port of the channel 1; Connect the test piece B and the compensation piece B to the measurement port and compensation port of the channel 2; In the test interface of the dynamic strain gauge, channel 1 is selected as the signal channel. The strain signal of the measuring rod is acquired through the test piece A and converted into the change in resistance of the test piece A. ; The dynamic output voltage of the bridge measurement circuit in the dynamic strain gauge is calculated using the following formula: in, The output voltage of the bridge measurement circuit is... The DC voltage supplied by the dynamic strain gauge to the bridge measurement circuit; The output voltage of the bridge measurement circuit is acquired using the dynamic strain gauge. The dynamic strain of the measuring rod is then calculated based on the simulated output values ​​displayed by the dynamic strain gauge. The formula is as follows: in, The simulated output displayed by the dynamic strain gauge. The amplification factor of the amplifier in the dynamic strain gauge is given by: , The sensitivity coefficient of the first resistive strain gauge or the second resistive strain gauge; The dynamic strain of test piece A was obtained based on the above steps. , Including the strain of the measuring rod and the interference of the strain gauge; In the test interface of the dynamic strain gauge, channel 2 is selected as the signal channel, and the dynamic strain of test piece B is calculated using the same method. , Only includes interference from strain gauges; The true dynamic strain of the measuring rod is calculated using the following formula: 。 10. The method for measuring dynamic stress in a giant magnetostrictive transducer according to claim 6, characterized in that: The soft-fixed supermagnetic-strict transducer includes: The giant magnetostrictive transducer is suspended in the air by a soft rope, and the lower end of the giant magnetostrictive transducer is vertically fixed to the ground by a soft rope.

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