A dynamic stress measurement system and method for a giant magnetostrictive transducer

Abstract

The application discloses a kind of super magnetostrictive transducer dynamic stress measurement system and method.There is power supply circuit;Super magnetostrictive transducer, the power supply circuit is connected with the super magnetostrictive transducer, the super magnetostrictive transducer includes vibrator and shell, the vibrator is arranged in the shell, and the upper end and lower end of the vibrator are connected with the shell;Measuring rod, the upper end and lower end of the vibrator are equipped with the measuring rod, and are connected with the shell by the measuring rod;First diamagnetic field strain gauge, including two first resistance strain gauges and first insulating material film, two the first resistance strain gauges are respectively test piece A and test piece B, the test piece A is bonded with the measuring rod;Dynamic strain meter, the positive electrode line and negative electrode line of the first diamagnetic field strain gauge are respectively connected with the access channel of the dynamic strain meter.Effectively measure the actual stress variation inside super magnetostrictive transducer.

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 is focused 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 caused by the alternating magnetic field and mechanical vibration, the conventional measurement method has the problems of difficult placement and low precision, and the induced voltage as the interference source has the same frequency as the dynamic stress of the transducer. This strong interference of the same frequency 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, so as 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 the giant magnetostrictive transducer provided by the embodiment of the present application, the system comprises:

[0007] a power supply circuit;

[0008] The super magnetostrictive transducer is connected with the power supply circuit, and the super magnetostrictive transducer comprises a vibrator and a shell, the vibrator is arranged in the shell, and upper and lower ends of the vibrator are connected with the shell;

[0009] The upper and lower ends of the vibrator are provided with the measuring rod, and the upper and lower ends of the vibrator are connected with the shell through the measuring rod;

[0010] 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;

[0011] The positive electrode lines and the negative electrode lines of the first anti-magnetic field strain gauge are connected with access channels of the dynamic strain gauge respectively, and the dynamic strain gauge is placed at a position far from the super magnetostrictive transducer, so that the magnetic field generated by the super magnetostrictive transducer does not interfere with the dynamic strain gauge.

[0012] The super magnetostrictive transducer dynamic stress measurement system according to the embodiment of the application has at least the following beneficial effects:

[0013] 1. The measuring rod is added in 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 operation performance of the super magnetostrictive transducer.

[0014] 2. The first anti-magnetic field strain gauge is made by the method of three layers of "two strain gauges + insulating layer" being overlapped and bonded and positive or negative poles being connected. The bonding area is the periphery of the sensitive grid of the resistance strain gauge, 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 produce deformation 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 by itself, 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.

[0015] In summary, this invention utilizes an improved measurement circuit to effectively measure the dynamic stress inside a giant magnetostrictive transducer. The improved measurement circuit exhibits resistance to electromagnetic interference of the same frequency. Constructing this circuit requires only ordinary resistive strain gauges and dynamic strain meters, thus reducing the overall construction cost of the measurement system. Furthermore, the system employs a dual-layer test piece to acquire strain and interference signals in real time, enabling the established measurement system to more accurately measure the actual stress changes inside the transducer, thereby better monitoring the transducer's operating conditions.

[0016] According to some embodiments of the present invention, a compensation system is further included, the compensation system comprising a compensation rod and two second magnetic field resistance strain gauges, the two second magnetic field resistance strain gauges being arranged side by side on the compensation rod, the second magnetic field resistance strain gauges comprising:

[0017] Two second resistive strain gauges and a second insulating film are provided. The two second resistive strain gauges are overlapped in the same direction, and the second insulating film is disposed between the two second resistive strain gauges, with the edges of the two second resistive strain gauges bonded to the second insulating film. The positive or negative electrode lines of the two second resistive strain gauges are connected, and 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 respectively compensation element A and compensation element B, and compensation element A is bonded to the compensation rod. The compensation rod is located away from the supermagnetic-strictive transducer.

[0018] 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.

[0019] According to some embodiments of the present invention, the positive electrode wire and the negative electrode wire of the second antimagnetic strain gauge are respectively twisted pairs and connected to the access channel of the dynamic strain gauge.

[0020] According to some embodiments of the present invention, the positive electrode wire and the negative electrode wire of the first anti-magnetic field strain gauge are respectively twisted pairs and connected to the access channel of the dynamic strain gauge. If the length of the twisted pair is insufficient, an additional twisted pair can be connected externally.

[0021] According to some embodiments of the present invention, a matching capacitor board is also included, which is connected in series in the power supply circuit.

[0022] A method for measuring dynamic stress in a giant magnetostrictive transducer according to a second aspect of the present invention includes:

[0023] The above-mentioned super magnetostrictive transducer dynamic stress measurement system is constructed, and the shell is deformed by extrusion equipment to assemble the oscillator into the shell;

[0024] After the oscillator is assembled, the prestress of the supermagnetostrictive transducer is obtained. ；

[0025] The super magnetostrictive transducer is softly fixed;

[0026] Set the test parameters measured by the dynamic strain gauge;

[0027] 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:

[0028]

[0029] 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:

[0030] .

[0031] The dynamic stress measurement method for a giant magnetostrictive transducer according to embodiments of the present invention has at least the following beneficial effects: The present invention utilizes an improved measurement circuit to achieve effective measurement of the dynamic stress inside the transducer. The improved measurement circuit has the performance of resisting electromagnetic interference of the same frequency. Constructing this circuit only requires ordinary resistive strain gauges and dynamic strain meters, thereby reducing the construction cost of the entire measurement system. Furthermore, the system uses a dual-layer test piece to acquire strain and interference signals in real time, enabling the established measurement system to more effectively measure the actual stress changes inside the transducer and better monitor the operating conditions of the transducer.

[0032] According to some embodiments of the present invention, the prestress of the supermagnetostrictive transducer is obtained during the assembly process of the oscillator. include:

[0033] Release the pressure of the extrusion device, measure the strain of the super magnetostrictive transducer using the dynamic strain gauge 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:

[0034]

[0035] in, The prestress of the giant magnetostrictive transducer during the assembly of the oscillator. The strain values ​​measured by the dynamic strain gauge during the assembly process. The Young's modulus of the measuring rod;

[0036] 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. :

[0037] .

[0038] According to some embodiments of the present invention, the test parameters measured by the dynamic strain gauge include:

[0039] The bridge circuit of the Wheatstone measurement circuit in the dynamic strain gauge is a half-bridge one-to-one compensation method.

[0040] In the dynamic strain gauge, the strain gauge resistance value parameter of the bridge circuit in the bridge measurement circuit is set according to the following formula:

[0041]

[0042] 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.

[0043] Set the strain gauge sensitivity coefficient of the bridge equivalent in the bridge measurement circuit according to the following formula. :

[0044]

[0045] 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

[0046] Set the equivalent sensitivity coefficient of the strain gauge in the bridge measurement circuit according to the following formula. :

[0047]

[0048] in, The sensitivity coefficient is the first or the second resistive strain gauge.

[0049] According to some embodiments of the present invention, the total strain is measured and obtained by the dynamic strain gauge. and interference include:

[0050] The dynamic strain gauge is provided with two access channels, namely channel 1 and channel 2;

[0051] Connect the test piece A and the compensation piece A to the measurement port and compensation port of the channel 1;

[0052] Connect the test piece B and the compensation piece B to the measurement port and compensation port of the channel 2;

[0053] 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. ;

[0054] The dynamic output voltage of the bridge measurement circuit in the dynamic strain gauge is set by the following formula:

[0055]

[0056] in, The output voltage of the bridge measurement circuit is... The DC voltage supplied by the dynamic strain gauge to the bridge measurement circuit;

[0057] 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:

[0058]

[0059] 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;

[0060] 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;

[0061] Using channel 2 as the signal channel, the dynamic strain of test piece B was calculated using the same method. , Interference only includes test piece B;

[0062] The true dynamic strain of the measuring rod is calculated using the following formula:

[0063] .

[0064] According to some embodiments of the present invention, the soft-fixed supermagnetic-strict transducer comprises:

[0065] 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.

[0066] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0067] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0068] Figure 1 This is a schematic diagram of the dynamic stress measurement system for the giant magnetostrictive transducer in an embodiment of the present invention;

[0069] Figure 2 This is a schematic diagram of the manufacturing method of the first anti-magnetic field strain gauge in an embodiment of the present invention;

[0070] Figure 3 This is a schematic diagram of the transducer placement during dynamic stress measurement in an embodiment of the present invention;

[0071] Figure 4 This is a flowchart illustrating the steps of the dynamic stress measurement method for a giant magnetostrictive transducer in an embodiment of the present invention.

[0072] Figure 5 This is a schematic diagram of the one-to-one compensation circuit for a half-bridge in an embodiment of the present invention;

[0073] Figure 6 This is a diagram showing the change in prestress during the transducer assembly process in an embodiment of the present invention;

[0074] Figure 7 This is a dynamic stress waveform diagram measured under the condition of a current amplitude of 8A and an excitation frequency of 300Hz in an embodiment of the present invention.

[0075] Figure 8This is a dynamic stress wave diagram measured under the conditions of a current amplitude of 8A and an excitation frequency of 400Hz in an embodiment of the present invention.

[0076] Figure 9 The image shows the dynamic stress waveform measured under the conditions of a current amplitude of 8A and an excitation frequency of 500Hz in this embodiment of the invention.

[0077] Figure label:

[0078] Vibrator 100; housing 200; soft rope 300; first anti-magnetic field strain gauge 400; twisted pair 500; measuring rod 600. Detailed Implementation

[0079] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0080] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the system or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0081] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0082] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0083] Reference Figures 1 to 3 As shown, the dynamic stress measurement system for a giant magnetostrictive transducer of the present invention includes:

[0084] Power supply circuit;

[0085] A giant magnetostrictive transducer, with a power supply circuit connected to the giant magnetostrictive transducer, the giant magnetostrictive transducer including an oscillator 100 and a housing 200, the oscillator 100 being disposed inside the housing 200, and the upper and lower ends of the oscillator 100 being connected to the housing 200.

[0086] Measuring rod 600 is provided at both the upper and lower ends of the vibrator 100, and is connected to the housing through the measuring rod 600;

[0087] The first magnetic field resistance strain gauge 400 includes two first resistive strain gauges and a first insulating material film. The two first resistive strain gauges are stacked 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 electrode lines or negative electrode lines of the two first resistive strain gauges are connected. The unconnected electrode lines serve as the positive electrode lines and negative electrode lines of the first magnetic field resistance strain gauge. The two first resistive strain gauges are test piece A and test piece B, respectively. Test piece A is bonded to the measuring rod 600.

[0088] The positive and negative electrode lines of the first anti-magnetic field strain gauge are connected to the access channel of the dynamic strain gauge. The dynamic strain gauge is placed far away from the super magnetostrictive transducer to avoid magnetic field interference with the dynamic strain gauge.

[0089] In this embodiment, the power supply circuit uses an AC power supply to apply AC current excitation to the giant magnetostrictive transducer, and the frequency and amplitude of the excitation can be adjusted. In this embodiment, 380V AC mains power is specifically used.

[0090] The giant magnetostrictive transducer, as the object of dynamic stress measurement, is mainly composed of an oscillator 100 and a shell 200. The dynamic stress is the real-time stress on the oscillator 100.

[0091] It should be noted that the measuring rod 600 possesses high magnetic permeability and good mechanical response speed, used to convert the dynamic stress of the giant magnetostrictive transducer into deformation and achieve magnetic circuit conduction. Common aluminum, copper, silver, and gold rods cannot meet the requirements, but some iron-nickel alloys can be used as substitutes. In this embodiment of the invention, the measuring rod 600 is a soft iron rod, which combines high magnetic permeability and good mechanical response speed, while also being inexpensive and cost-effective. The following embodiments will all use a soft iron rod as the measuring rod 600.

[0092] refer to Figure 2 As shown, in this embodiment, two identical first resistive strain gauges are selected as the first anti-magnetic field strain gauges. The width of their sensitive grids must be less than 1 / 10 of the diameter of the soft iron rod to ensure that the bending angle of the sensitive grids attached to the side of the soft iron rod is not too large. The two first resistive strain gauges are placed simultaneously with their bases facing down, and the sensitive grids of the two are aligned in the vertical direction. A first insulating material film is placed between them to isolate the static electricity generated by the friction of the first resistive strain gauge shell.

[0093] refer to Figure 2As shown, a bonding area Q is defined around the outer edge of the sensitive grid on the first resistive strain gauge. Adhesive is applied to the area Q of the two strain gauges and they are bonded to the first insulating material film respectively, ensuring that there are no obvious gaps between the three. This makes the two first resistive strain gauges at the same spatial measurement point (with the same interference), and the test piece B will not deform with the test piece A bonded to the measuring rod 600. At the same time, the dynamic deformation of the test piece A will not affect the resistance value of the test piece B.

[0094] Connect the terminals of the two first resistive strain gauges at the same potential, that is, connect the positive electrode wires or the negative electrode wires of the two first resistive strain gauges. This cancels out the approximately identical induced interference voltages of the two strain gauges in opposite directions.

[0095] In this embodiment, the positive electrode wires of two first resistive strain gauges are selected as the terminals connected at the same potential. Specifically, the positive electrode wires of the two first resistive strain gauges are trimmed to the minimum welding length, and the two positive electrode wires are welded together. Each of the two first resistive strain gauges will have one negative electrode wire remaining. These two negative electrode wires serve as the overall lead wires, i.e., as the positive and negative terminals of the first anti-magnetic field strain gauge as a whole. This is because the induced voltage generated by the magnetic field interference of the two first resistive strain gauges... They are basically the same, and the voltage flow direction is also the same. After the positive electrode wires of the two first resistive strain gauges are connected, the two induced voltages... They can basically cancel each other out automatically.

[0096] The positive and negative electrode lines of the first anti-magnetic field strain gauge are connected to the access channel of the dynamic strain gauge to measure the dynamic strain of the measuring rod 600 over time.

[0097] Furthermore, the two negative electrode leads, which serve as the lead wires, are wound together to form a twisted pair 500. Alternatively, an external twisted pair can be connected to extend the length of the twisted pair 500. Then, it is wrapped with solid glue to fix its shape. Wrapping the twisted pair 500 allows the two leads to alternately self-cancel each other in the presence of magnetic field interference, thereby reducing interference factors.

[0098] The specific bonding method between the first anti-magnetic field strain gauge and the soft iron rod is as follows:

[0099] 1) By simulating the spatial numerical distribution of the magnetic field in the soft iron rod, the magnetic field strength distribution law of "small in the middle and large at both ends" is obtained. A point located outside the giant magnetostrictive transducer is selected at the middle section of the side of the soft iron rod and used as the measurement point of dynamic stress. The measurement point and its surrounding area are polished and cleaned with sandpaper.

[0100] 2) Since the dynamic stress of the giant magnetostrictive transducer is at the same frequency as the alternating magnetic field, interference cannot be eliminated by filtering and magnetic shielding. Therefore, a control group is set up to simulate interference and achieve self-cancellation of interference. Test piece A is glued to the measurement point to measure the total strain of the soft iron rod (including interference), and the glue is allowed to dry to set its shape. Test piece B is aligned and placed on test piece A, with the two isolated by an insulating film. Test piece B is used to collect the interference signal (mainly the induced voltage caused by the alternating magnetic field interference on the sensitive grid and leads when the giant magnetostrictive transducer vibrates), and cancels the interference from 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).

[0101] In some embodiments of the present invention, a compensation system is further included. The compensation system includes a compensation rod and two second magnetic field resistance strain gauges. The two second magnetic field resistance strain gauges are arranged side by side on the compensation rod. The second magnetic field resistance strain gauges include:

[0102] Two second resistive strain gauges and a second insulating film are provided. The two second resistive strain gauges are overlapped in the same direction. The second insulating 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 film. The positive or negative electrode lines 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 respectively compensation component A and compensation component B. Compensation component A is bonded to the compensation rod.

[0103] The positive and negative electrode lines of the second anti-magnetic field strain gauge are connected to the access channel of the dynamic strain gauge, respectively.

[0104] In this embodiment, a soft iron rod is used as a compensation rod. An area on its side is ground and cleaned, and two second anti-magnetic field strain gauges are then attached to this area. (Reference) Figure 2 The fabrication method of the second anti-magnetic field strain gauge is the same as that of the first anti-magnetic field strain gauge, and will not be described in detail here. The two second anti-magnetic field strain gauges are used for temperature compensation and are respectively set up in the circuits containing the two first anti-magnetic field strain gauges, thus forming a one-to-one compensation circuit.

[0105] By incorporating a compensation rod, measurement errors caused by changes in ambient temperature can be compensated for. The lead wires of the second anti-magnetic strain gauge are twisted into a twisted pair and fixed with solid glue to eliminate magnetic field interference.

[0106] In some embodiments of the present invention, a matching capacitor board is also included, which is connected in series with the power supply circuit.

[0107] 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.

[0108] 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.

[0109] refer to Figure 4 The present invention also discloses a method for measuring dynamic stress in a giant magnetostrictive transducer, comprising:

[0110] 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.

[0111] After the oscillator 100 is assembled, the prestress of the supermagnetostrictive transducer is obtained. ；

[0112] Soft-fixed super magnetostrictive transducer;

[0113] 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:

[0114]

[0115] 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:

[0116] .

[0117] 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. .

[0118] In addition, the compensating rod and dynamic strain gauge are placed far away from the giant magnetostrictive transducer, at a distance of more than 5 meters. Actual measurements show that the magnetic field generated by the coil at a distance of 5 meters from the giant magnetostrictive transducer is very weak, ensuring that the alternating magnetic field will not interfere with the dynamic strain gauge and compensating components.

[0119] When leading out the wire, bend the twisted pair at a 90° angle, with the bend point close to the solder joint between the strain gauge and the twisted pair. This suspends the twisted pair and prevents it from contacting the flexible iron rod, thus reducing wire vibration. Glue the wire at the bend point to the flexible iron rod and wrap it with solid adhesive to enhance the toughness of the twisted pair lead.

[0120] Clamp the twisted pair cable at 1 / 3 and 2 / 3 of its length using metal clamps, suspending the latter part in the air to prevent the twisted pair cable from contacting any vibrating objects (including soft iron rods, vibrators, coils, and other transducer components). Wrap the lead wire (let's call it line segment Y) between the first clamp and the bending point with solid soft rubber for protection. Wrap both ends of line segment Y with metal sleeves to ensure it doesn't bend (to prevent contact with vibrating objects). Keep the middle section of line segment Y hanging down naturally to minimize the mechanical vibration transmitted to the twisted pair cable during transducer operation, thus protecting the twisted pair cable from being snapped.

[0121] The twisted-pair cable connecting the test piece is laid in a straight line along the side of the transducer to avoid contact with the giant magnetostrictive transducer, which would cause greater vibration (increased interference). Its end is connected to the dynamic strain gauge. The twisted-pair cable connecting the compensation piece is also connected to the dynamic strain gauge. All twisted-pair cables are kept to the same length (same resistance) to avoid the different resistances of the first and second anti-magnetic field strain gauges affecting the bridge balance, which would cause the output voltage to deviate from the expected value and reduce the measurement accuracy.

[0122] In this embodiment, the magnetostrictive transducer is fixed using a soft-fixation method. This allows the transducer to operate in a relatively fixed position in the air, preventing it from contacting other objects during vibration. Specifically, the upper end of the transducer is suspended in the air by a soft rope 300, and the lower end is vertically fixed to the ground by the same rope. The leads (twisted pairs) of test pieces A and B are led out from the side of the transducer. The end of the shielded twisted pair of test piece A is connected to channel 1 of the dynamic strain gauge, and the lead of compensation piece A is connected to the compensation port of channel 1 via a twisted pair. Test piece B and its compensation piece B are then connected to channel 2 of the dynamic strain gauge in the same manner. The shielding layers of all twisted pairs are grounded through wires, allowing the induced charge on the shielding layers to be conducted to the ground, thus achieving high-frequency magnetic shielding.

[0123] A current excitation of a certain frequency and amplitude is applied to the giant magnetostrictive transducer using an AC power supply. In this example, the current amplitude is uniformly 8A, and the excitation frequencies are 300Hz, 400Hz, and 500Hz.

[0124] In the dynamic strain gauge test interface, select channel 1 as the strain signal channel, and then use the analog output voltage of channel 1. To calculate the total dynamic strain of the soft iron rod The formula is as follows:

[0125]

[0126] in, This is the simulated output voltage of the dynamic strain gauge. This represents the amplification factor of the analog circuit in the dynamic strain gauge. The DC voltage supplied by the dynamic strain gauge to the bridge circuit. This is the equivalent sensitivity coefficient of the test piece.

[0127] In the dynamic strain gauge test interface, select channel 2 as the interference signal channel, and then analyze the simulated output voltage based on channel 2. The equivalent strain of the disturbance is calculated using the following formula. The formula is as follows:

[0128]

[0129] The true dynamic strain of the soft iron rod is then calculated using the following formula. :

[0130]

[0131] Based on dynamic strain The mechanical parameters of the soft iron rod were used to calculate the actual dynamic stress in the giant magnetostrictive transducer using a dynamic strain gauge. The specific calculation formula is as follows:

[0132]

[0133] in, For the dynamic stress of the transducer, This is the Young's modulus of the soft iron rod.

[0134] This invention improves the strain gauge setting method under alternating magnetic fields by adopting a method for manufacturing anti-magnetic field strain gauges that involves overlapping and bonding the edges of resistive strain gauges and welding them with the same pole. This allows the first and second anti-magnetic field strain gauges to self-cancel the induced voltage of the sensitive grid in the alternating magnetic field. Furthermore, the invention improves the half-bridge one-to-one compensation circuit for the anti-magnetic field strain gauges and uses a long twisted-pair shielded cable with a fixed clamp at the head end for long-distance connection to the dynamic strain gauge. This significantly reduces magnetic field interference caused by conductor vibration and magnetic field interference on the strain gauge, making the dynamic stress measurement of the system more accurate.

[0135] In the dynamic stress measurement method of giant magnetostrictive transducers, a double-layered first anti-magnetic field strain gauge is used as the test piece. The strain value and interference value of the first anti-magnetic field strain gauge are measured separately. This allows the measurement circuit to automatically distinguish the interference signal in the strain, further optimizing the measurement accuracy of the system. Moreover, the measurement response speed is fast, enabling real-time measurement of dynamic stress, which plays a good role in verifying the design and development of transducers.

[0136] Compared with existing technologies, this invention utilizes an improved measurement circuit to effectively measure the dynamic stress inside the transducer. The improved measurement circuit has the ability to resist electromagnetic interference of the same frequency. Constructing this circuit only requires ordinary resistive strain gauges and dynamic strain meters, thereby reducing the construction cost of the entire measurement system. Furthermore, the system uses a dual-layer test piece to acquire strain and interference signals in real time, enabling the established measurement system to more effectively measure the actual dynamic stress changes inside the transducer and better monitor the transducer's operating conditions.

[0137] In some embodiments of the present invention, after the oscillator 100 is assembled, the prestress of the supermagnetostrictive transducer is obtained. include:

[0138] Release the pressure in the extrusion equipment until the pressure is 0 and the strain value stabilizes. Obtain the change in strain value throughout the entire depressurization process, and calculate the prestress value using the following formula:

[0139]

[0140] in, Prestressing of the giant magnetostrictive transducer during the assembly of oscillator 100. These are the strain values ​​measured by a dynamic strain gauge during the assembly process. To measure the Young's modulus of rod 600;

[0141] refer to Figure 6 As shown, according to the assembly process Numerical changes, acquisition initial stress value and the stress value after stabilization The prestress of oscillator 100 after assembly is obtained by the following formula. :

[0142] .

[0143] In some embodiments of the present invention, the test parameters measured by the dynamic strain gauge include:

[0144] The bridge circuit configuration of the Wheatstone measurement circuit in the dynamic strain gauge is a half-bridge one-to-one compensation method.

[0145] The dynamic strain gauge includes two access channels, namely channel 1 and channel 2;

[0146] Connect test piece A and compensation piece A to the measurement port and compensation port of channel 1;

[0147] Connect test piece B and compensation piece B to the measurement port and compensation port of channel 2;

[0148] In a dynamic strain gauge, the strain gauge resistance value parameter of the bridge circuit in the Wheatstone bridge measurement circuit is set according to the following formula:

[0149]

[0150] in, The value represents the equivalent strain gauge resistance of the bridge circuit in the Wheatstone bridge measurement circuit. The resistance value of a single first or second resistance strain gauge. This represents the resistance value of a single wire in a twisted-pair cable (500).

[0151] Set the strain gauge sensitivity coefficient of the bridge equivalent in the Wheatstone bridge measurement circuit according to the following formula. :

[0152]

[0153] in, The Poisson's ratio of the sensing grid of the first or 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

[0154] Set the equivalent sensitivity coefficient of the strain gauge in the Wheatstone bridge measurement circuit according to the following formula. :

[0155]

[0156] in, This is the sensitivity coefficient of the first or second resistive strain gauge.

[0157] refer to Figure 5 As shown, a half-bridge one-to-one compensation circuit is used. This circuit uses fewer components and has a temperature compensation function. Then, the measurement parameters of this circuit are set in the dynamic strain gauge.

[0158] Place the soft iron rod with the compensation component and the dynamic strain gauge away from the giant magnetostrictive transducer. Fix the lead wire of the compensation component with a metal clamp and glue, in the same way as the test piece, to avoid the lead wire from touching the vibrating object.

[0159] In some embodiments of the present invention, the total strain is measured and obtained by a dynamic strain gauge. and interference include:

[0160] The dynamic strain gauge is equipped with two access channels, namely channel 1 and channel 2;

[0161] Connect test piece A and compensation piece A to the measurement port and compensation port of channel 1;

[0162] Connect test piece B and compensation piece B to the measurement port and compensation port of channel 2;

[0163] In the dynamic strain gauge test interface, select channel 1 as the signal channel, acquire the strain signal of the measuring rod through test piece A, and convert it into the change in resistance of test piece A. ;

[0164] The dynamic output voltage of the bridge measurement circuit in a dynamic strain gauge is set using the following formula:

[0165]

[0166] in, The output voltage of the bridge measurement circuit. The DC voltage supplied by the dynamic strain gauge to the bridge measurement circuit;

[0167] The output voltage of the bridge measurement circuit is acquired using a dynamic strain gauge. Then, the dynamic strain of the measuring rod 600 is calculated based on the simulated output values ​​displayed by the dynamic strain gauge. The formula is as follows:

[0168]

[0169] in, This is the analog output displayed by the dynamic strain gauge. This refers to the amplification factor of the amplifier in the dynamic strain gauge. The sensitivity coefficient of the first or second resistive strain gauge;

[0170] The dynamic strain of test piece A was obtained based on the above steps. , Including strain from the measuring rod and interference from the strain gauge;

[0171] Using channel 2 as the signal channel, the dynamic strain of test piece B was calculated using the same method. , Only includes interference from strain gauges;

[0172] The true dynamic strain of the measuring rod is calculated using the following formula:

[0173] .

[0174] Based on dynamic strain The actual dynamic stress is inferred from the material properties, and the specific formula is as follows:

[0175]

[0176] in, For the dynamic stress of the giant magnetostrictive transducer, This is the Young's modulus of the soft iron rod.

[0177] refer to Figures 7 to 9 As shown, the dynamic stress waveforms measured in this embodiment of the invention are obtained under the conditions that the current amplitude is uniformly 8A and the excitation frequency is 300Hz, 400Hz and 500Hz respectively.

[0178] In some embodiments of the present invention, the soft-fixed supermagnetic-strict transducer includes:

[0179] The giant magnetostrictive transducer is suspended in the air by a soft rope 300, and the lower end of the giant magnetostrictive transducer is vertically fixed to the ground by the soft rope 300.

[0180] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

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. 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 field strain gauge are respectively connected to the access channel of the dynamic strain gauge; Both the measuring rod and the compensating rod are made of soft iron.

2. 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 second anti-magnetic field strain gauge are twisted pairs and connected to the access channel of the dynamic strain gauge.

3. 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.

4. 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.

5. 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 4 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: 。 6. The method for measuring dynamic stress in a giant magnetostrictive transducer according to claim 5, 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. : 。 7. 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.

8. The method for measuring dynamic stress in a giant magnetostrictive transducer according to claim 7, 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: 。 9. The method for measuring dynamic stress in a giant magnetostrictive transducer according to claim 5, 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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