CN1304848C - Horizontal magnetic coupler mechanical loading and measuring systems - Google Patents

Abstract

The horizontal force-magnetic coupling mechanical loading and measuring system belongs to the technical field of magnetic characteristic measurement, and is characterized in that it proposes two types of systems: lateral loading and measurement under a magnetic field, and three-point bending fracture experiment loading and measurement under a magnetic field. Its control part adopts digital control and measurement subsystem, and its loading part adopts motor or manual lateral loading mechanism and manual spiral three-point pressure fracture loading mechanism respectively. It can realize the continuous loading of force-magnetic coupling under the magnetic field, and it also has the advantages of large force and magnetic load and high measurement accuracy.

Description

Horizontal Force-Magnetic Coupling Mechanical Loading and Measurement System

technical field

The invention belongs to the technical field of material magnetic parameter and characteristic measurement.

Background technique

At present, the magnetic property measurement technology of magnetic materials has matured, and various magnetic measuring instruments have been commercialized. However, although the research on the force-magnetic coupling behavior of magnetic materials has made some progress, there are no corresponding experimental equipment and instruments for studying the force-magnetic coupling behavior. In the article of R.Tickle, RDJames (Journal of Magnetism and Magnetic Materials 195 (1999) 627-638) studying the magnetic and mechanical properties of Ni ₂ MnGa, the equipment for studying the force-magnetic coupling experiment is mentioned, but this set of equipment can be loaded The magnetic field strength is relatively small, and the precision of the load loading device is low, and continuous loading cannot be achieved. Due to the use of soft spring loading, the load that can be loaded is also very small. The functions that can be realized by the whole set of equipment are relatively few, and Figure 9 is a schematic diagram of its loading.

Contents of the invention

The purpose of the present invention is to provide a horizontal force-magnetic coupling mechanical loading and measuring system with high force-magnetic loading intensity, high precision and continuous loading.

People have studied the force-magnetic coupling behavior of magnetic materials since a long time ago, and found that stress is one of the important factors affecting the magnetic properties of ferromagnetic materials. As the stress state changes, the coercive field, saturation magnetization, permeability, saturation magnetostriction, and piezomagnetic coefficient of the magnetic material will all change. With the development of science and technology, the application of magnetic materials is becoming more and more extensive, new magnetic materials are constantly emerging, and the working environment is becoming more and more complex. This requires systematic research on the force-magnetic coupling behavior of magnetic materials, so we have developed a horizontal force-magnetic coupling mechanical loading and measurement system.

principle

The constitutive relation of ferromagnetic materials under quasi-static conditions can be expressed as

ε _ij =ε _ij (σ _ij , H _i ) (1)

B _i =B _i (σ _ij , H _i ) (2)

Among them, σ _ij is the stress, ε _ij is the strain, B _i is the magnetic induction intensity, and H _i is the magnetic field intensity. It can be seen from the constitutive equation that when the independent variables are stress and magnetic field intensity, the output quantities are strain and magnetic induction. These four quantities are the basic quantities that must be measured in the experiment. Through these four quantities, we can obtain characteristic curves reflecting the properties of ferromagnetic materials, such as hysteresis loops, magnetostrictive curves, stress-strain curves, etc. Further, from these basic characteristic curves, important material parameters can be measured .

Measurement of Magnetic Field Strength

According to different physical principles, the measurement of magnetic field can be divided into: force and torque method, electromagnetic induction method, magnetoelectric effect method and resonance method. We use the magnetoelectric effect method in the measurement, which uses the Hall effect, is simple and convenient to use, and has high precision. Place a current-carrying semiconductor in a magnetic field. If the direction of the current is perpendicular to the direction of the magnetic field, a potential difference U _H will be generated in the vertical direction of the current. This phenomenon is called the Hall effect. The Hall electromotive force can be determined by the following formula

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}}{\mathrm{<span\; class="notranslate">\; d</span>}}\mathrm{<span\; class="notranslate">\; IB</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Where R _H is the Hall coefficient, I is the current intensity in the sample, d is the thickness of the sample, and B is the magnetic induction. Since the magnetic susceptibility of materials with the Hall effect is far less than 1, then B≈μ ₀ H, substituting into the above formula, the magnetic field strength can be obtained

$\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; d</span>}}{{\mathrm{<span\; class="notranslate">\; \&mu;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}\mathrm{<span\; class="notranslate">\; I</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Measurement of Magnetic Induction

According to the law of electromagnetic induction, when the magnetic flux Φ passes through a section with N turns of coil and changes within Δt time, an electromotive force U _e will be generated, and its integration can obtain the magnetic flux variation ΔΦ within Δt time

$\mathrm{\&Delta;\&Phi;}=\frac{1}{N}\frac{u_e}{R}\mathrm{\&Delta;t}$ R: coil resistance (5)

When the initial state from t=0 is the reference point, the magnetic induction intensity is expressed as

$B=\frac{\mathrm{\&Phi;}}{S}=\frac{\mathrm{\&Delta;\&Phi;}}{S}$ S: cross-sectional area (6)

stress measurement

force sensor

Strain measurement

Strain can be measured optically and electrically. Due to the characteristics of simple use and high precision of electrical measurement, we use traditional resistance strain gauges to measure strain.

Measurement of Hysteresis Loop

There are three types of hysteresis loops: B-H curve, M-H curve and J-H curve. Among them, there is the following relationship among the magnetization M, the magnetic polarization J and the magnetic induction B

B＝H+J＝H+4πM (Gaussian) (7)

B＝μ ₀ (H+M)＝μ ₀ H+J (SI unit) (8)

As long as the magnetization M is known, any value of the magnetic polarization J and the magnetic induction B can be calculated according to formula (7). In our experiment, the J coil is used, that is, the J value is obtained directly.

Take the B-H curve as an example to illustrate the hysteresis loop measurement principle. Firstly, the motor is loaded to make the specimen bear a certain load, and the load can be measured by the force sensor. Then control the excitation power supply through the D/A card, load the magnetic field, and use the Hall plate to measure the magnetic field strength, and transmit the collected voltage signal to the A/D card. At the same time, obtain the magnetic induction B value through the coil and transmit it A/D card, the two sets of data are automatically recorded by the computer to obtain the B-H curve.

Measurement of Magnetostrictive Curve

The magnetostriction when measured is actually relative magnetostriction, defined as follows:

λ＝ _εH - _εH＝0 (9)

That is, relative to the deformation when no magnetic field is applied. When measuring the magnetostriction at a certain stress σ, it is necessary to take into account

ε _{H = 0} = ε(σ) (10)

At this time, ε _{H = 0} is the deformation caused by simple stress σ. In the 0 stress state λ=ε _H , the magnetostriction is the measured strain.

The measurement of the magnetostriction curve is similar to the measurement of the hysteresis loop. Firstly, the motor is loaded to make the specimen bear a certain load, and the load can be measured by the force sensor. Then control the excitation power supply through the D/A card, load the magnetic field, and use the strain gauge to measure the magnetostriction and introduce the signal into the A/D card. At the same time, measure the magnetic field strength through the Hall plate and introduce it into the A/D card. The computer automatically records these two sets of curves to obtain the magnetostriction curve.

Stress-strain curve measurement

First, control the excitation power supply through the D/A card, load the magnetic field, and then load it through the motor, so that the specimen bears a certain load, use the stress sensor to obtain the stress signal, and obtain the strain signal through the resistance strain gauge, and at the same time, these two sets of signals are introduced into the A/D Card, automatically recorded by the computer, so as to obtain the stress-strain curve.

Three point bending line measurement

First, control the excitation power supply through the D/A card, load it to a certain magnetic field, and then manually load it through the vertical loading device, so that the specimen bears a certain load on the three-point bending fixture until it breaks, and uses the stress sensor to obtain the maximum breaking load. The A/D card is automatically recorded by the computer to obtain the stress-strain curve.

Stress demagnetization curve

First, control the excitation power supply through the D/A card, load it to a certain magnetic field, and then load it through the motor, use the stress sensor to obtain the stress signal, measure the signal of the magnetic induction intensity through the J coil, and at the same time introduce the signal into the A/D card, which is automatically recorded by the computer , so as to obtain the stress demagnetization curve.

Measurement of basic material parameters

The basic parameters of the material can be obtained from the magnetization curve, magnetostriction curve, and stress-strain curve. The elastic modulus can be measured directly from the stress-strain curve.

The magnetic permeability and magnetic susceptibility are defined as

$\mathrm{<span\; class="notranslate">\; \&mu;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; B</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&chi;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

Since the magnetic permeability and magnetic susceptibility depend on the loading history, different magnetic permeability can be defined according to different application ranges, such as initial magnetic permeability, differential magnetic permeability, etc. The relationship between permeability and susceptibility is as follows

                                              

The coercive field H _c , remanence magnetization M _r , and saturation magnetization are important basic material constants of ferromagnetic materials, which can be measured from the MH curve. A schematic diagram of the measurement is given in Figure 1. Then the coercive field H _cb and the residual magnetic induction B _r can be measured from the BH curve. Note that there will be a little difference between H _c and H _cb .

In Figure 1, the x-axis is the magnetic field strength and the y-axis is the magnetization. Data collection is at discrete points. When calculating the coercive field, two points (H ₁ , M ₁ ) and (H ₂ , M ₂ ) closest to zero magnetization are taken, where M ₁ <0 and M ₂ >0. Since the coercive field is the value of the magnetic field intensity when the magnetization is zero, the coercive field H _c can be obtained by interpolating (H ₁ , M ₁ ) and (H ₂ , M ₂ ). For hard magnetic materials, the magnetization curve has a certain slope when passing through the coercive field, so the coercive field H _c is the value corresponding to M=0 on the line connecting (H ₁ , M ₁ ) and (H ₂ , M ₂ ), which can be expressed as

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

For soft magnetic materials, the magnetization curve is almost perpendicular to the x-axis when passing through the coercive field, then M ₁ and M ₂ are almost equal, which will lead to overflow calculated according to the above formula. So H _c can be approximated as the midpoint of two points

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="h"\; filenames="C20041004278700162.png,C20041004278700171.png"\; state="\{\{state\}\}">h</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

The measurement of remanence magnetization is similar to the coercive field measurement, take the two points (H ₁ ′, M ₁ ′) and (H ₂ ′, M ₂ ′) closest to the zero magnetic field, where H ₁ ′<0 and H′>0 ₂ , the residual magnetization can be obtained

$\mathrm{<span\; class="notranslate">\; Mr.</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="m"\; filenames="C20041004278700162.png,C20041004278700171.png"\; state="\{\{state\}\}">m</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="h"\; filenames="C20041004278700162.png,C20041004278700171.png"\; state="\{\{state\}\}">h</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

Measurement steps

●Parameter setting (sample area, length, maximum magnetic field to be achieved, setting of magnetic field and magnetic induction range)

●Preparation work before the test (check whether the test piece has been installed, whether the gauss meter and the sensor are zeroed, whether the strain gauge is balanced, whether the strain bridge is correct, whether the strain gauge is normal, whether the fluxmeter drift is adjusted, the Apc button (automatic control switch) button) is pressed, whether the button of the integrator pops up (after the measurement starts, these buttons are invalid), whether the Hall probe and J coil are installed correctly, whether the position of the pole head is adjusted, whether the motor displacement limit is correct, etc.)

Select the curve to be measured (hysteresis loop, magnetostrictive curve, etc.) to start measurement.

The horizontal force-magnetic coupling mechanical loading and measuring system of the present invention is characterized in that it is a lateral loading and measuring system under a magnetic field, which consists of a control subsystem, a fluxmeter, a Gauss meter, an excitation power supply, and a lateral loading sub-system. System composition:

1) The control subsystem is composed of industrial computer, A/D converter, D/A converter, stress sensor and dynamic strain gauge, among which:

A/D converter, its input/output end is interconnected with the control signal output end of the industrial computer and the input end of the data signal;

D/A converter, its input/output end is interconnected with the control signal output end and data signal input end of the industrial computer;

Stress sensor, its output end is connected with the input end of above-mentioned A/D converter after integral circuit;

Dynamic strain gauge, its output end links to each other with the input end of above-mentioned A/D converter after integrating circuit;

2) fluxmeter, its output end is connected with the input end of above-mentioned A/D converter, and its range adjustment signal input end is connected with the range control signal output end of above-mentioned D/A converter;

3) Gauss meter, its output end is connected with the data input end of above-mentioned A/D converter, and its range adjustment signal input end is connected with the range control signal output end of above-mentioned D/A converter;

4) excitation power supply, its input end is connected with the control signal output end of above-mentioned D/A converter;

5) The lateral loading subsystem consists of a base, a test piece, an induction coil, a strain gauge, a Hall probe, a DC magnetic field coil with an electromagnet pole, a guide rail, and a lateral loading mechanism for a test piece, among which:

(a) The induction coil is axially wound on the test piece and fixed with a coil frame, and the two output terminals are connected to the input terminals of the above-mentioned fluxmeter;

(b) The strain gauge is attached to the test piece in the axial direction, and its output end is connected to the input end of the above-mentioned dynamic strain gauge;

(c) Hall probe, fixed on the base with a fixing frame, and the position of the probe is close to the lower side of the test piece, and its two output terminals are connected to the input terminals of the above-mentioned Gauss meter;

(d) There are two DC magnetic field coils with electromagnet pole heads, which are powered by the above-mentioned excitation power supply. The center lines of the coils are coaxial with the test piece. DC magnetic field;

(e) There are two guide rails, which are respectively distributed on both sides of the radial direction of the test piece along the length direction of the base, and fixed on the edge of the base outside the coil;

(f) The lateral loading mechanism of the specimen is located on the left side of the specimen along the axial direction. It consists of a specimen lateral loading frame, a loading motor and a manual loading wheel, a transmission shaft, a loading plate on the left side of the specimen axial direction, and a left chuck. The lateral loading adjustment mechanism of the specimen, the strain sensor, the loading plate on the right side of the axial direction of the specimen, the right chuck and the positioning plate are composed of:

√The lateral loading frame of the test piece is in the shape of "匚", located on the two guide rails on the radial side, a loading frame is fixed between its two arms, and one is fixed on the lateral loading frame of the test piece on the left side of the reinforcement frame. Displacement limiter on the inside of the arm;

√The drive shaft, one end is coaxial with the loading motor and the manual loading wheel, and is coaxially threaded with the lateral loading frame of the specimen, and the other end is slidably fixed on the reinforcement frame through a bearing;

√The loading plate on the left side of the specimen axis, which is fixed at the opening ends of the two arms of the transverse loading frame of the specimen;

√The left chuck, one side is fixed on the loading plate on the left side of the specimen axis, and the other side clamps the specimen axially from the left;

√The lateral load adjustment mechanism of the test piece is located on the right side of the axial direction of the test piece, including: two adjustment plates, which are respectively located on the radial side guide rails of the test piece;

√Strain type force sensor, fixed on the side of the adjustment plate facing the test piece;

√The loading plate on the right side of the specimen axis is fixed on the other side of the strain type force sensor;

√Right chuck, one side is fixed on the loading plate on the right side of the specimen axis, and the other side clamps the specimen axially from the left;

√There are two positioning plates, which are respectively located on the two guide rails on the radial side of the test piece, and there is an adjustment gap between it and the other side of the adjustment plate.

The horizontal force-magnetic coupling mechanical loading and measuring system of the present invention is characterized in that it is a three-point bending fracture experiment loading and measuring system under a magnetic field, which consists of a control subsystem, a fluxmeter, a gaussmeter, and an excitation power supply , consisting of a loading subsystem for three-point bending fracture experiments, where:

1) The control subsystem is composed of industrial computer, A/D converter, D/A converter, stress sensor and dynamic strain gauge, among which

A/D converter, its input/output end is interconnected with the control signal output end of the industrial computer and the input end of the data signal;

D/A converter, its input/output end is interconnected with the control signal output end and data signal input end of the industrial computer;

A strain sensor whose output is connected to the input of the above-mentioned A/D converter;

Dynamic strain gauge, its output end links to each other with the input end of above-mentioned A/D converter after integrating circuit;

2) fluxmeter, its output end is connected with the input end of above-mentioned A/D converter after integrating circuit, its range adjustment signal input end is connected with the range control signal output end of above-mentioned D/A converter;

3) Gauss meter, its output end is connected with the data input end of above-mentioned A/D converter, and its range adjustment signal input end is connected with the range control signal output end of above-mentioned D/A converter;

4) excitation power supply, its input end is connected with the control signal output end of above-mentioned D/A converter;

5) The loading subsystem of the three-point bending fracture experiment consists of a base, a test piece, an induction coil, a strain gauge, a Hall probe, a DC magnetic field coil with an electromagnet pole, and a loading mechanism for the three-point bending fracture experiment, among which:

(a) The induction coil is axially wound on the test piece and fixed with a coil frame, and the two output terminals are connected to the input terminals of the above-mentioned fluxmeter;

(b) The strain gauge is attached to the test piece in the axial direction, and its output end is connected to the input end of the above-mentioned dynamic strain gauge;

(c) Hall probe, fixed on the base with a fixing frame, and the position of the probe is close to the lower side of the test piece, and its two output terminals are connected to the input terminals of the above-mentioned Gauss meter;

(d) There are two DC magnetic field coils with electromagnet pole heads, which are powered by the above-mentioned excitation power supply. The center lines of the coils are coaxial with the test piece. DC magnetic field;

(e) The loading mechanism for the three-point bending fracture experiment consists of a fixed frame, a transmission shaft, a strain-type pressure sensor, a three-point bending indenter, a three-point bending loading base, a three-point bending loading support, and a test piece, among which:

√The fixing frame is fixed on the above-mentioned base along the direction of the centerline of the above-mentioned coil, and is sandwiched between the above-mentioned coils at equal distances;

√The transmission shaft, one end is coaxially connected with a manual wheel, and passes through the above-mentioned fixing frame coaxially;

√Strain type pressure sensor, the upper end surface of which is coaxially embedded with the lower end of the above-mentioned transmission shaft;

√Three-point bending head, the upper end surface of which is coaxially embedded with the lower end surface of the above-mentioned strain type pressure sensor, and at the same time is coaxially threaded by the guide frame fixed between the two arms of the above-mentioned fixing frame;

√The three-point bending loading base is coaxially fixed on the bottom frame of the above-mentioned fixing frame;

√The three-point bending loading support is coaxially fixed on the upper end surface of the above-mentioned three-point bending loading base;

√The test piece is clamped in the above-mentioned three-point bending loading support, and the center of the upper end face is against the top of the above-mentioned three-point bending indenter. on the base above.

Figure 2 shows the various components of the experimental equipment in detail. Since this set of equipment not only performs constitutive experiments but also fracture experiments, in order to meet our requirements and automate the measurement process, we developed the monitoring and data acquisition software for the measurement process. Under the control of the monitoring software, the stress and strain signals are respectively introduced into the A/D card through the force sensor and the dynamic strain gauge, and the magnetic field intensity and magnetic induction intensity are converted into the A/D card through the integrator. The computer controls the magnetic field loading through the D/A card. At the same time as the magnetic field is loaded, the computer collects the magnetic induction, strain and stress signals synchronously through the A/D, and automatically processes and records the data.

Through this set of equipment, comprehensive constitutive experiments can be carried out, and hysteresis loops under different stress states, magnetostriction curves under different stress states, stress-strain curves under different magnetic field intensities, and stress regression under different magnetic field intensities can be measured. magnetization curve, etc.

Description of drawings

Figure 1. Schematic diagram of magnetic parameter measurement.

Figure 2. Schematic diagram of lateral loading experimental equipment:

1-Loading motor 4-Electromagnet 6-Indenter 7-Cylindrical specimen 8-Hall probe 9-J coil 13-Strain force sensor 17-Displacement limiter 20-Strain gauge

Figure 3. Schematic diagram of the experimental equipment for three-point bending fracture under a magnetic field:

4-Electromagnet 8-Hall probe 24-Strain force sensor 27-Three-point bending support 28-Flake specimen

Figure 4. Schematic diagram of the signal acquisition principle.

Figure 5. Cross-sectional view of the horizontal force-magnetic coupling mechanical mechanism:

5a: longitudinal sectional view; 5b: left side view; 5c: top view; 5d: enlarged view;

1. Loading motor 2. Manual loading wheel 3. Lateral loading frame 4. Electromagnet 5. Loading plate 6. Indenter 7. Cylindrical test piece 8. Hall probe 9. J coil 10. Strain type force sensor 11. Adjustment Plate 12. Hall probe fixing frame 13. Strain force sensor output end 14. Equipment base 15. Transmission shaft part 16. Reinforcement frame 17. Displacement limiter 18. Guide rail 19. Fixing bolt 20. Strain gauge.

Figure 6. Circuit block diagram of the control subsystem.

Figure 7. Sectional view of the loading mechanism of the three-point bending fracture experiment:

7a: longitudinal sectional view; 7b: left side view; 7c: top view; 7d: enlarged view;

21. Longitudinal loading manual wheel 22. Longitudinal fixing frame 23. Transmission shaft 24. Strain type force sensor 25. Guide frame 26. Three-point bending indenter 27. Three-point bending loading support 28. Thin sheet specimen 29. Three points curved loading base

Figure 8. Experimental curves.

Figure 9. R.Tickle, R.D.James Loading Mechanism

30. Bracket 31. Test piece 32. Spring 33. Test piece table 34. Nut

Detailed ways

(1) Magnetic field generating equipment

The magnetic field is generated by direct current passing through an electromagnet. In order to have high magnetic field and high precision at the same time, two sets of power supplies are designed: ① A small power supply rectified by transistors, with a maximum output current of 20A and a maximum power of 2KW. When the pole spacing is 80mm, the maximum magnetic field can reach 0.4T, and the magnetic field fluctuates within 10 minutes Less than 1%; ②Large power supply through thyristor rectification, the maximum output current is 50A, the maximum power is 15KW, when the pole spacing is 80mm, the maximum magnetic field can reach 1.2T, and the magnetic field fluctuation is less than 3% within 3 minutes. For general soft magnetic materials, a small power supply is used, the magnetic field is stable and the precision is high. For hard magnetic materials or magnetic materials with a saturation field greater than 1T, a large power supply can be used.

(2) Magnetic field measuring equipment

The magnetic field strength is measured by the Hall probe, and the magnetic induction is measured by the coil. The two original analog signals are introduced into the integrator and converted into analog signals that can be directly collected by the A/D card. The A/D card is 14 bits.

(3) Mechanical loading equipment

The lateral loading and longitudinal loading equipment are designed respectively. The loading in these two directions is displacement loading, the vertical loading is through the worm gear transmission, and the lateral loading is the stepless speed regulation electrode loading. The lateral loading range is 1000 kg force, and the longitudinal loading range is 200 kg force.

By loading the frame longitudinally, installing the indenter and the base, the three-point bending test can be realized. As shown in Figure 3.

(4) Monitoring and collection equipment

The whole experiment process is controlled by computer, and the power loading is controlled by D/A, and signals such as magnetic field intensity, magnetic induction intensity, stress and strain are collected by A/D. As shown in Figure 4.

(1) D/A control unit number of digits The output voltage minimum resolution Number of switches 12 0-±5V 1/2 ¹² *10V 12

(2) A/D acquisition unit number of digits Input voltage minimum resolution Number of sampling channels 14 0-±1V 1/2 ¹⁴ *2V 8

(3) Excitation power supply: MTP-500HB (small power supply) Output current The output voltage power requirements ±20A DC(Max) ±100V DC(Max) 220V, 50/60Hz

(4) Excitation power supply: MTP-5000H (large power supply) Output current The output voltage power requirements ±50A DC(Max) ±300V DC(Max) 380V power supply

Power supply features: Realize automatic protection of current overload Manual adjustment of current output

(5) Gauss meter: TA101A (for H measurement) Range (automatic setting and manual setting) header display repeatability accuracy 0.4T, 1.0T, 2.0T, 4.0T 31/2 digital display 1% full scale ±1% full scale

(6) Fluxmeter: TA101A (for B measurement) Range (automatic setting and manual setting) header display repeatability accuracy 200,000, 500,000, 1 million, 2 million 31/2 digital display 1% full scale ±1% full scale

(7) Electromagnet shape weight Pole Gap Coil impedance Operating temperature horizontal About 1000kg 0-110mm 9Ω Maximum 50°C extreme head Maximum magnetic field (small power supply) Maximum magnetic field (large power supply) φ100 pure iron 0.4T (gap 80mm) 1.2T (gap 80mm)

(8) JH-compensation coil (4) Coil size Suitable sample size Coil Thickness Operating temperature φ6mmφ10mmφ10mmφ14mm φ4-φ6φ8-φ10φ8-φ10φ12-φ14 4mm4mm7mm8mm Max 40°C

(9) Dynamic strain gauge

Automatic balance bridge, output voltage signal ±10V

(10) Force sensor (2 pcs)

A: Range 1 ton, accuracy 1N

B: Range 100 kg force, accuracy 0.1N

(11) Adjustable speed motor and motor control box

Load range: 11000N

Stable load transmission: the worm rotates once, and the step displacement of the loading head does not exceed 0.05mm.

overload protection

(12) Technical requirements for loading device:

Neutral: less than 0.4mm

Maximum deflection: less than 0.5mm

(13) Loading device material: non-magnetic materials such as stainless steel

Advantages and functions of the equipment: The horizontal force-magnetic coupling mechanical loading and measuring system can achieve high magnetic field strength, large mechanical loading range and high precision, and the mechanical loading uses stepping motor loading to achieve continuous loading. All measurement signal acquisition and processing are completed by computer software, and the entire measurement process is automated. There are two sets of mechanical loading devices, which can realize loading and measuring experiments in two directions perpendicular to and parallel to the magnetic field, and the fixture of the specimen can be replaced, and can complete tension, compression and three-point bending experiments. It can realize the hysteresis loop and magnetostriction curve under different loading methods and different stress states; the stress demagnetization curve and stress-strain curve under different loading methods and different magnetic field strengths; it can also carry out three-point bending experiments and Indentation experiment. And this set of equipment can continue to develop many functions, such as combined potentiometer, which can measure the electromagnetic effect under different stress states, and can also measure the magneto-induced phase transition curve under different force-magnetic coupling loads, etc. And when measuring the strain signal, the strain signal line adopts magnetic shielding line, which eliminates the noise signal caused by the magnetic field. The full bridge is used to measure the strain, which reduces the influence of the bending moment.

Claims (2)

1. horizontal power magnetic coupling mechanical load and measuring system is characterized in that: it is laterally to load and measuring system under a kind of magnetic field, by control subsystem, and fluxmeter, gaussmeter, field power supply laterally loads subsystem and forms:

1) control subsystem is by industrial computer, A/D converter, and D/A converter, strain gauge, dynamic strain indicator is formed, wherein:

A/D converter, its input/go out end to interconnect with the control signal output ends of industrial computer, the input end of data-signal;

D/A converter, its input/go out end to interconnect with industrial computer control signal output ends, data-signal input end;

Strain gauge, its output terminal link to each other with the input end of above-mentioned A/D converter behind integrating circuit;

Dynamic strain indicator, its output terminal link to each other with the input end of above-mentioned A/D converter behind integrating circuit;

2) fluxmeter, its output terminal links to each other with the input end of above-mentioned A/D converter, and its range conditioning signal input end links to each other with the range control signal output ends of above-mentioned D/A converter;

3) gaussmeter, its output terminal links to each other with the data input pin of above-mentioned A/D converter, and its range conditioning signal input end links to each other with the range control signal output ends of above-mentioned D/A converter;

4) field power supply, its input end links to each other with the control signal output ends of above-mentioned D/A converter;

5) laterally load subsystem, by base, test specimen, inductive coil, foil gauge, hall probe, the D.C. magnetic field coil of charged magnet cartridge, guide rail, the horizontal load maintainer of test specimen is formed, wherein:

(a) inductive coil fixes on test specimen and with coil former vertically, and two output terminals link to each other with the input end of above-mentioned fluxmeter;

(b) foil gauge is attached on the test specimen vertically, and its output terminal links to each other with the input end of above-mentioned dynamic strain indicator;

(c) hall probe is fixed on the base with fixed mount, and the downside of the close test specimen in the position of probe, its two output terminal links to each other with above-mentioned gaussmeter input end;

(d) the D.C. magnetic field coil of charged magnet cartridge, totally two, by above-mentioned field power supply power supply, coil centerline is all coaxial with test specimen, and coil lays respectively at the base of the axial left and right sides of test specimen, produces the D.C. magnetic field of work alternate with each other;

(e) guide rail, is distributed in radially both sides of test specimen along the base length direction respectively, and is fixed on the base limit in the coil outside by totally two;

(f) the horizontal load maintainer of test specimen, be positioned at test specimen left side vertically, by the horizontal loading frame of test specimen, loading motor and manual loading wheel, transmission shaft, test specimen is the load plate in left side axially, and left chuck, test specimen laterally load adjusting mechanism, the strain type force transducer, the load plate on the axial right side of test specimen, right chuck and location-plate are formed, wherein:

The horizontal loading frame of √ test specimen is " Contraband " font, is positioned on two guide rails of radial side, is fixed with a loading frame between its two arms, in the strengthening frame left side displacement limiter that is fixed on an arm inboard of the horizontal loading frame of this test specimen is arranged;

The √ transmission shaft, an end and loading motor and manual loading wheel are coaxial, and are connected with the horizontal loading frame coaxial threaded of this test specimen and the other end is fixed on the strengthening frame through bearing slidably;

The √ test specimen is the load plate in left side axially, and it is fixed on the openend of horizontal loading frame two arms of this test specimen;

√ left side chuck, a side is fixed on the load plate in the axial left side of test specimen, and opposite side is axially clamped test specimen from left margin;

The √ test specimen laterally loads adjusting mechanism, is positioned at the axial right side of test specimen, comprising: adjust plate, totally two, lay respectively on the test specimen radial side guide rail;

√ strain type force transducer is fixed on and adjusts the side of plate in the face of test specimen;

The load plate on the axial right side of √ test specimen is fixed on the opposite side of strain type force transducer;

The right chuck of √, a side is fixed on the load plate on the axial right side of test specimen, and opposite side is axially clamped test specimen from left margin;

The √ location-plate, totally two, lay respectively on two guide rails of test specimen radial side, it and adjust between the plate opposite side adjusting play arranged.

2. horizontal power magnetic coupling mechanical load and measuring system is characterized in that, it is that following 3 the curved fracture experiments in a kind of magnetic field load and measuring system, by control subsystem, and fluxmeter, gaussmeter, field power supply, 3 curved fracture experiments load subsystem to be formed, wherein:

1) control subsystem is by industrial computer, A/D converter, and D/A converter, strain gauge, dynamic strain indicator is formed, wherein

A/D converter, its input/go out end to interconnect with the control signal output ends of industrial computer, the input end of data-signal;

D/A converter, its input/go out end to interconnect with industrial computer control signal output ends, data-signal input end;

Strain gauge, its output terminal links to each other with the input end of above-mentioned A/D converter;

Dynamic strain indicator, its output terminal link to each other with the input end of above-mentioned A/D converter behind integrating circuit;

2) fluxmeter, its output terminal link to each other with the input end of above-mentioned A/D converter behind integrating circuit, and its range conditioning signal input end links to each other with the range control signal output ends of above-mentioned D/A converter;

3) gaussmeter, its output terminal links to each other with the data input pin of above-mentioned A/D converter, and its range conditioning signal input end links to each other with the range control signal output ends of above-mentioned D/A converter;

4) field power supply, its input end links to each other with the control signal output ends of above-mentioned D/A converter;

5) 3 curved fracture experiments load subsystem, by base, and test specimen, inductive coil, foil gauge, hall probe, the D.C. magnetic field coil of charged magnet cartridge, 3 curved fracture experiment load maintainers are formed, wherein:

(a) inductive coil fixes on test specimen and with coil former vertically, and two output terminals link to each other with the input end of above-mentioned fluxmeter;

(b) foil gauge is attached on the test specimen vertically, and its output terminal links to each other with the input end of above-mentioned dynamic strain indicator;

(c) hall probe is fixed on the base with fixed mount, and the downside of the close test specimen in the position of probe, its two output terminal links to each other with above-mentioned gaussmeter input end;

(d) the D.C. magnetic field coil of charged magnet cartridge, totally two, by above-mentioned field power supply power supply, coil centerline is all coaxial with test specimen, and coil lays respectively at the base of the axial left and right sides of test specimen, produces the D.C. magnetic field of work alternate with each other;

(e) 3 curved fracture experiment load maintainers, by fixed mount, transmission shaft, the strain type pressure transducer, 3 curved pressure heads, 3 curved loaded seat, 3 curved bearings that load, test specimen is formed, wherein:

The √ fixed mount is fixed on the above-mentioned base along the centerline direction of above-mentioned coil, and equidistant being clipped between the above-mentioned coil;

The √ transmission shaft, an end and coaxial a connection of manual pulley, and pass the said fixing frame coaxially;

√ strain type pressure transducer, its coaxial cable ground, upper surface and the interlocking of above-mentioned transmission shaft lower end;

3 curved pressure heads of √, the interlocking of the lower surface of its coaxial cable ground, upper surface and above-mentioned strain type pressure transducer simultaneously again by being threaded with being fixed on guide frame coaxial cable between said fixing frame two arms;

3 curved loaded seat of √ are fixed on the underframe of said fixing frame coaxial cable;

3 curved bearings that load of √ are fixed on the upper surface of above-mentioned 3 curved loaded seat coaxial cable;

The √ test specimen is clipped in above-mentioned 3 curved loadings in the bearing, and the center of upper surface heads on the top of above-mentioned 3 curved pressure heads, and respectively there is a bearing at test specimen face two ends, and these two bearings are fixed on the above-mentioned base.

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