JPH08219965A - Test equipment for electromagnetic force load - Google Patents

Abstract

PURPOSE: To perform experiment over a wide region in strong field without requiring a large scale facility by combining a plurality of field sources, i.e., normal conducting electromagnetic coils, and altering the conduction timing of power supply according to the purpose of experiment. CONSTITUTION: Based on a signal from a controller 31, a charge storing unit 6 feeds two electromagnetic coils 1 with a current of trapezoidal waveform. Planar and rod-like test pieces 14 are then set in a field test region produced by the coil 1 and the field distribution is altered by altering the position of the coil 1 thus performing experiment in a space of uniform field or gradient field corresponding to the angle. When a rod-like test piece 15 being set in the field of the coil 1 is conducted directly by a charge storing unit 13, experiment of electromagnetic load can be carried out through interaction of a current I and field. Furthermore, when a proximity coil 2 is conducted by a charge storing unit 10 using other test piece, a magnetic force is loaded to the test piece through interaction of the field and an induced eddy current or a current being fed directly 13 to the test piece and the behavior thereof can be measured 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic force load test apparatus for evaluating the structural strength and soundness of equipment used in an electromagnetic field.

[0002]

2. Description of the Related Art As a conventional electromagnetic force load device, for example, "6th Electromagnetic Force-related Dynamics Symposium Proceedings p. 151" (co-sponsored by: The Japan Society of Mechanical Engineers, The Institute of Electrical Engineers of Japan,
As shown in FIG. 15, there is a superconducting magnet or a permanent magnet 4 as a magnetic field generation source in the AEM Society of Japan, '94 .7).
5 is arranged alone or two magnets are arranged in parallel, and a uniform magnetic field having a magnetic flux density B is created in the test area. Then, a fluctuating magnetic field is applied to the test body 15 placed in the magnetic field to induce an eddy current, and the electromagnetic force F is applied according to Fleming's left-hand rule. Alternatively, the power source 46 is supplied to the test body 15 placed in the magnetic field.
The electric current is directly applied from and the electromagnetic force F is applied.

The use of a superconducting magnet can generate a strong stationary magnetic field, but has the disadvantage that it requires large-scale auxiliary equipment such as a refrigeration equipment for cooling the magnet to an extremely low temperature. The use of a permanent magnet has the advantages that it is simple and that a steady magnetic field with few error factors can be obtained, but on the other hand, it is difficult to create a large magnetic field region because the magnet itself has a limit of magnetic force. As an electromagnetic force load test used for structural strength evaluation in an electromagnetic field, a magnetic field above a certain level is required to destroy the test body, but if the magnetic field is increased, the magnetic field area becomes narrower, so component tests such as There is a disadvantage that it is not possible to carry out experiments using such large test specimens. Furthermore, since the strength of the magnetic field cannot be changed, it is unsuitable for experiments in which the correlation between magnetic field strength and phenomena is investigated.

An apparatus for arranging magnets in parallel to generate a magnetic field has a merit that since it is a uniform magnetic field, it has few error factors and is suitable for a basic test for clarifying the phenomenon. However, the environment in which the structure is actually placed is not necessarily a uniform magnetic field, and is not sufficient as a structural strength evaluation facility for equipment placed in an actual electromagnetic field environment. For example, since the reactor structure of a fusion reactor is placed in a gradient magnetic field distribution in which toroidal coils are circumferentially arranged, in order to grasp the behavior with respect to electromagnetic force load more accurately, such a gradient of the magnetic field is used. A device that can perform a test in a simulated environment is required.

[0005]

When a superconducting magnet is used, auxiliary equipment such as a cooling device other than the magnet and the power source becomes large in scale and lacks in simplicity. With a permanent magnet, the magnetic field area is narrow, and experiments using large-scale test bodies such as component tests cannot be performed. In addition, the magnetic field strength cannot be changed. Also,
With the device in which these superconducting magnets or permanent magnets are arranged in parallel, the test can be performed only in a uniform magnetic field environment, and the behavior of the structure in an environment where the magnetic field distribution is inclined cannot be grasped.

[0006]

[Means for Solving the Problems] The source of the magnetic field is a normal conductive magnetic coil, a power supply for supplying current to the coil is provided, and a plurality of normal conductive coils are combined to change the power supply timing according to the purpose of the experiment. By doing so, it is possible to perform an experiment in a large area and in a strong magnetic field, which is not possible with a permanent magnet, without requiring large-scale auxiliary equipment unlike the case of a superconducting magnet. Also, by making it possible to disassemble the fastening part of the support structure of the electromagnetic coils that generate a magnetic field and exchange the support structure of the electromagnetic coils, the angle between the electromagnetic coils can be set to a predetermined angle in addition to the parallel arrangement. To achieve a gradient of the magnetic field distribution,
Allows experiments in such magnetic fields.

[0007]

Since the electromagnetic coil is used, it is possible in principle to increase the size of the electromagnetic coil, that is, the test space, infinitely depending on the capability of the power supply. Also, the magnitude of the magnetic field generated by adjusting the current can be controlled. For example, a steady magnetic field can be created by applying a direct current. In addition, it is possible to apply a transient magnetic field or a fluctuating magnetic field to the test body by supplying a transient current or a fluctuating current to the coil. Further, if the energizing current waveform is a trapezoidal wave, it can be regarded as a pseudo stationary magnetic field in the time range in which the current value is constant. If a quasi-stationary magnetic field using this trapezoidal wave is used, it is not necessary to keep the current flowing. In other words, the current is kept constant only for the time required for the experiment, which is economical in terms of energy, and as a result, a large magnetic field with less energy is required as compared with a device having a structure in which a constant current is continuously supplied. Can be generated.

By giving an angle between the electromagnetic coils, the magnetic field becomes stronger on the side where the electromagnetic coils are closer to each other,
The magnetic field becomes weaker on the side where the electromagnetic coils are distant from each other, so that the magnetic field distribution can have a gradient. If the support structure for the electromagnetic coils is prepared in advance, the angle between the electromagnetic coils can be set arbitrarily, and the degree of inclination of the magnetic field distribution can be adjusted accordingly. Then, it is possible to perform an experiment in a magnetic field having such a gradient magnetic field distribution. That is, since the angle between the coils can be arbitrarily changed, experiments can be performed in either a uniform magnetic field or a magnetic field with a gradient.

[0009]

FIG. 1 shows an embodiment of the present invention, which is actually manufactured. The main body of this device consists of two magnetic field coils 1 for generating a magnetic field in the test area, a proximity coil 2 for generating a magnetic flux penetrating the test body to induce an eddy current in the test body, and those coils. The support 3 for supporting the is used as a main constituent member, and the plate-shaped test body 4, the rod-shaped test body 15, or an arbitrary test body can be set in the magnetic field test region formed by the magnetic field coil 1. As power supply equipment for energizing the coil, there are charge storage devices 6, 10, and 13, which are collectively managed by a control device 31. A signal from the control device 31 is used as a trigger to discharge the stored charge, thereby causing a current to flow through each coil. In this embodiment, as the charge storage device 6, a high voltage capacitor 8 and a low voltage capacitor 9 connected in parallel via a coil 17 are connected to the magnetic field coil 1 via a waveform controller 7. When this charge storage device 6 is used, a trapezoidal current can be applied to the coil. The magnetic field coil 1 is another magnetic field coil 1 arranged next to each other.
Are electrically connected in series, and the same current flows through the two coils. By changing the arrangement of the coils, it is possible to change the distribution of the magnetic field by changing the angle between the coils. As an example, if two coils are arranged in the shape of a Helmholtz coil installed coaxially in parallel and separated by the distance of the coil radius, the cylindrical area made by the two coils will be spatially uniform everywhere. Experiments can be carried out in a uniform magnetic field. Moreover, if the angle between the coils is set to an arbitrary angle, an experiment in a space having a magnetic field gradient according to the angle is possible. The charge storage device 10 includes a plurality of capacitors 1 via a waveform controller 11.
2 is composed of capacitor banks connected in parallel, and the waveform control device 11 energizes the proximity coil 2 according to a desired current waveform. The charge storage device 13 has the same configuration. In order to carry out this experiment, the rod-shaped test body 15 is set in the magnetic field created by the magnetic field coil 1, and the rod-shaped test body 15 is directly energized from the charge storage device 13 to generate an electromagnetic force due to the interaction between the current I and the magnetic field. Perform a load test. Further, by using another test body, an electromagnetic force is applied to the test body by the interaction between the eddy current induced by the energization of the proximity coil 2 and the magnetic field, or the interaction between the current and the magnetic field directly applied to the test body. Then, grasp the behavior of the test piece after that. Therefore, this device has the measuring device 5 and can measure the deformation such as strain and displacement of the test body or the electrical behavior such as eddy current. The measuring device 5 is also managed by the control device 31, and the measurement in consideration of the timing of energization is shown in FIG. 2 which is an embodiment of claim 2 and is actually measured. Each current value was measured when electricity was applied using the charge storage device 6 and the charge storage device 10 shown in FIG. The magnetic field coil current enters a steady state in about 40 ms from the start of energization, and thereafter this state continues for 40 ms and gradually decreases. In the current steady state for 40 ms, the magnetic field is also steady. Therefore, for example, as shown in FIG. 2, if the energizing current to the proximity coil is made to finish flowing within this time, the experiment can be performed in a stationary magnetic field. The maximum current can be set arbitrarily by changing the charging voltage to the capacitor. Further, even if the value of the current changes, the time change of the current does not change as shown in FIG.

FIG. 3 shows an embodiment of the discharge delay device according to claim 3. This device is composed of capacitors 12 connected in parallel in multiple stages via energization time adjustment coils 17, and the trapezoidal trapezoids as shown in FIG. A corrugated current can be applied.

FIG. 4 shows an embodiment of claim 4. Using the superconducting magnetic energy storage device 18 as a charge storage device,
The trapezoidal wave control device 19 makes the current into a trapezoidal wave having a time period in which the current value becomes steady, and then the magnetic field coil is energized. Since the superconducting magnetic energy storage device 18 has a large energy density, it can carry a large current with a compact device.

FIG. 5 shows an embodiment of claim 5. In this device, three types of coil support members 3 for fixing the coil in the coil case and setting the inter-coil angle 2α of 0 °, 15 °, and 30 ° were manufactured. This member has a plate-shaped pedestal welded to the end face of H-shaped steel, and the angle α of this pedestal is
Is produced by changing. The angle between the coils can be arbitrarily set by changing α. Since the fastening between the support member 3 and the coil case can be disassembled, various experiments can be performed by selecting these support members according to the purpose of the experiment and fixing the coil. In this device, the inter-coil angle 2α can be set to 0 °, 15 °, and 30 °. In the case of 0 °, an experiment in a uniform magnetic field is possible, and in the angle setting of 15 ° and 30 °, an experiment in an inclined magnetic field is possible.

FIG. 6 shows an embodiment of claim 6. When only the bolts are fastened, a bending moment or a shearing force is generated in the bolt when the coil is overturned, resulting in insufficient strength. Therefore, between the pedestal 48 welded to the coil case 47 and the pedestal of the support member 3. The cotter 50 is driven in to strengthen the fastening. Since the fastening is made by driving the bolt 49 and the cotter 50, this fastening can be disassembled.

FIG. 7 shows an embodiment of claim 7. The charge storage device 13 is connected to the rod-shaped test body 15 provided with the electrodes 20 at both ends and set in the test region, and the power is supplied at the timing shown in FIG. Magnetic flux density Bt generated by the magnetic field coil 1
Rod-shaped test body 1 set with the direction and angle of
When a current flows through 5, electromagnetic force is applied according to Fleming's left-hand rule. Destruction tests are performed by this electromagnetic force load to evaluate the strength under electromagnetic field. FIG. 16 shows measured data when an experiment is actually performed using this apparatus. With the setup shown in the figure, a strain gauge was attached to the test piece 15 at the position shown in the figure, and the strain and the test piece current were measured. The horizontal axis of the graph is the elapsed time from the start of measurement, and the vertical axis is the current value and strain value applied to the test body. It shows the change over time in strain from the electromagnetic force being applied to the destruction. In this experiment, it was destroyed 0.9 ms after the electromagnetic force was started, and it was slightly delayed from the time when the electromagnetic force became maximum. I understood.

FIG. 8 shows an embodiment of claim 8. The conductive plate-shaped test body 4 is set in the magnetic field region of the magnetic field coil 1 and near the proximity coil 2. Then, the power is supplied at the timing shown in FIG. When the proximity coil 2 is energized while the magnetic field coil 1 is generating the steady magnetic field Bt, the proximity coil 2 generates a magnetic field having a magnetic flux density Bh penetrating the plate-shaped test body 4. The eddy current is induced so that the magnetic flux is generated in the direction that prevents the change of the magnetic flux density Bh penetrating the test body. The electromagnetic force F is applied to the plate-shaped test body 4 by the interaction between the eddy current and the magnetic flux density Bt created by the magnetic field coil 1. From the vibration of the conductive test piece in such a magnetic field,
Experiments to understand the behavior of electromagnetic structure coupled vibrations can be conducted. FIG. 17 shows the result of an experiment conducted using this apparatus. By placing the plate-shaped test body 4 in the external magnetic field BT generated by the magnetic field coil 1 and energizing the proximity coil, the BT
This is a measurement of the behavior when an eddy current is induced by applying a fluctuating magnetic field that is orthogonal to the and penetrates the test body 4 and an electromagnetic force is applied to the test body 4 by the eddy current. The graph shows plate-shaped test body 4
3 is an example of measuring the eddy currents that orbit the test body and the displacement at each position. The horizontal axis represents the elapsed time from the start of measurement, the vertical axis represents the eddy current value induced in the test body, and the displacement from the stationary state.
When the magnetic field coil 1 was energized and the proximity coil 2 was energized in the presence of the external magnetic field BT, eddy current oscillation that could not be seen when there was no external magnetic field was confirmed. It is considered that this is because the vibration of the plate-shaped test body 4 is coupled with the magnetic field generated by the magnetic field coil 1 to induce an eddy current different from the initial eddy current. Further, it can be seen that the vibration is vertically symmetrical at both ends of the test body, and the vibration mode is a twisting vibration mode.

FIG. 9 shows an embodiment of the measuring means of claim 9. The strain detector 22 and its amplifier 23, the laser displacement gauge probe 24 and its amplifier 25, the Rogowski coil 26 and its integrator 27 for measuring the current I, the magnetic probe 28 and its integrator 29, and the test The mechanical and electrical transient properties of the body can be measured. FIG. 9 shows the case of the experiment using the rod-shaped test body 15, but the same applies to the case of using the plate-shaped test body or another test body. These outputs are collectively captured by the data collection device 30. This data collection device 3
0, the charge storage device 6, the charge storage device 13, or the charge storage device 10 is managed by the control device 31, and the measurement can be started and ended at an arbitrary timing in synchronization with energization.

FIG. 10 shows an embodiment of the repetitive charging / discharging device according to claim 10. It comprises a charge / discharge control device 33, a charger 34, a discharger 35 and a charge storage device. In this example, the charge storage device 6 is used as the charge storage device.
Although the case is shown, the same applies to the case of the charge storage device 10 and the charge storage device 13. The number of repetitions is set in the charge / discharge control device 33. The charging and discharging are repeated until the charger 34 and the discharger 35 are operated by the control signal and the prescribed number of times is completed. Thereby, the electromagnetic force is repeatedly applied to the test body, and the fatigue test by the electromagnetic force in the electromagnetic field can be performed.

FIG. 11 shows an embodiment of claim 11. An AC generator 36 is used as a charge storage device. In this example, the case of the charge storage device 13 is shown, but the same applies when the charge storage device 6 and the charge storage device 10 are used.
By applying an alternating current to the rod-shaped test body 15 in the magnetic field created by the magnetic field coil 1, it is possible to apply an alternating load in which the direction of the electromagnetic force alternates. This makes it possible to carry out a fatigue test in an electromagnetic field. The same experiment can be performed when the current flowing through the test body is stationary and the current flowing through the magnetic field coil 1 is alternating current.

FIG. 12 shows an embodiment of claim 12. A potential difference measuring device 37 measures a potential difference between two points sandwiching a notch or a crack in the rod-shaped test body. An electromagnetic force F is applied to the test body 15 by a current-carrying test in a magnetic field, but if a crack propagates at this time, the cross-sectional area of the test body 15 becomes smaller and the resistance increases and the potential difference becomes larger. By measuring the time change of this potential difference, it is possible to know the behavior of the crack growth of the object due to the electromagnetic force in the electromagnetic field. Further, by feeding back this output to the controller 31, the experiment can be automatically stopped depending on the amount of crack growth.

FIG. 13 shows an embodiment of claim 13. The present embodiment is a processing machine to which the principle of the device is applied. this is,
The rod-shaped test body 15 is an arbitrary movable body 40, and a reaction force support structure 38 is provided. The movable body 40 and the reaction force support structure 38
During this period, the workpiece 39 is set as a set, and electricity is supplied from the charge storage device 6 and the charge storage device 13, respectively. Magnetic field coil 1
In the magnetic field generated by the work, the movable body 40 that is being energized receives an electromagnetic force, and the workpiece 3 placed between the movable body 40 and the reaction force support structure 38.
9 is loaded and variously processed.

FIG. 14 shows an embodiment of claim 14, and FIG.
The movable body 40 of No. 3 is a blade 41. The blade 41 has a guide 43 also serving as an electrode, and is guided by a guide rail 42 to move up and down. The workpiece 39 is placed between the blade 43 and the reaction force support device 38. Then, by energizing the charge storage device 6 and the charge storage device 13, respectively, the blade 41 is loaded with an electromagnetic force, thereby cutting the workpiece. This device is characterized by a high cutting speed.

[0022]

According to the present invention, it is possible to simulate a complicated current flow in an actual machine and arbitrarily adjust the timing of the electromagnetic force load. Also, the experiment can be performed in either a transient magnetic field or a steady magnetic field. With regard to the transient magnetic field, it is possible to select a state in which the changing speed is different, and it is possible to perform a fatigue test under repeated load loading by an electromagnetic force under an electromagnetic field.

[Brief description of drawings]

FIG. 1 is a block diagram of a device made in accordance with the present invention.

FIG. 2 is a timing chart of the trapezoidal waveform of the measured current when the magnetic field coil 1 is energized, the current waveform of the proximity coil 2 or the rod-shaped test body 15, and the energization.

FIG. 3 is an explanatory diagram of a discharge delay device according to claim 3, which generates a trapezoidal wave current.

FIG. 4 is a block diagram of an embodiment of a charge storage device using a superconducting magnetic energy storage device 18.

FIG. 5 is an explanatory diagram of an embodiment of a coil support structure that allows changing the angle between the coils.

FIG. 6 is an explanatory diagram of an embodiment of a disassembled coil fastening portion using a bolt and a cotter.

FIG. 7 is an explanatory diagram of an example of an electromagnetic force load test in which a test body is directly energized in a magnetic field.

FIG. 8 is an explanatory diagram of an example of a test in which an eddy current is induced in the test body and an electromagnetic force is applied to the test body by a change in a magnetic field generated by a coil close to the test body.

FIG. 9 is a block diagram of an embodiment of a measuring device for a test body that is interlocked with energization.

FIG. 10 is an explanatory diagram of an embodiment of a repetitive charging / discharging device for repeatedly applying electromagnetic force to a test body.

FIG. 11 is an explanatory diagram of an example of energizing an alternating current to load an alternating current on a test body.

FIG. 12 is an explanatory diagram of an embodiment of an apparatus for detecting damage to a test body by a potential difference.

FIG. 13 is an explanatory diagram of an embodiment of a processing machine to which the principle of the present device is applied.

FIG. 14 is an explanatory diagram of an embodiment of a cutting machine to which the principle of the present device is applied.

FIG. 15 is an explanatory diagram of an electromagnetic force load testing device using a conventional permanent magnet.

FIG. 16 is an explanatory view of an experimental example of an electromagnetic force load destruction test by directly energizing a test body.

FIG. 17 is an explanatory diagram of an example of a vibration test in which an electromagnetic force is loaded by inducing an eddy current in a test body.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic field coil, 2 ... Proximity coil, 3 ... Coil support, 4 ... Plate test body, 5 ... Measuring device, 6, 10, 13 ...
Charge storage device, 7 ... Waveform control device, 8 ... High voltage capacitor, 9 ... Low voltage capacitor, 11 ... Proximity coil current waveform control device, 12 ... Capacitor, 14 ... Specimen current waveform control device, 15 ... Rod-shaped test body, 17 ... Coil, 31 ... Control device.

Claims (14)

[Claims] 1. A test body placed in the magnetic field or a coil adjacent to the test body during a time period in which a current is supplied from a charge storage device to the coil for magnetic field generation to generate a magnetic field. An electromagnetic force load test apparatus, wherein an electric current is supplied from another charge storage device, and an electromagnetic force is applied to a test body by an interaction between the magnetic field and a current flowing through the test body. 2. The electromagnetic force load testing device according to claim 1, wherein a current waveform passing through the coil has a substantially trapezoidal shape to generate a pseudo steady magnetic field. 3. The electromagnetic force load testing device according to claim 1, wherein the charge storage device is a discharge delay device including a capacitor and a coil. 4. The electromagnetic force load testing device according to claim 1, wherein the charge storage device is a device combining a superconducting magnetic energy storage device and a trapezoidal wave device. 5. The electromagnetic load test according to claim 1, wherein the fastening structure of the support structure of the coil can be disassembled, and the angle between the coils can be changed by replacing the support structure of the coil. apparatus. 6. An electromagnetic force load testing device according to claim 5, wherein a fastening structure that can be disassembled is realized by using bolt fastening and a wedge. 7. The electrode according to claim 1, wherein electrodes are provided at both ends of the test body, the test body is installed in a direction forming an angle with a direction of a magnetic field generated by a magnetic field coil, and an electric current is passed through the test body to generate an electromagnetic wave. Electromagnetic force load test device that applies force. 8. The coil according to claim 1, wherein the coil is installed close to the test body, an electric current is caused to flow from the charge storage device to the coil, and an eddy current is generated in the test body to apply an electromagnetic force. An electromagnetic load tester that can change the restraint condition of the test body in the test. 9. The electromagnetic force load testing device according to claim 1, comprising means for measuring the behavior of the test body. 10. The electromagnetic force load test device according to claim 1, wherein the charge storage device is repeatedly incorporated with a charge / discharge mechanism to perform a repeated electromagnetic force load test. 11. The electromagnetic force load testing device according to claim 1, wherein an alternating electromagnetic force is applied by passing an alternating current from the charge storage device. 12. The electromagnetic force load testing device according to claim 1, wherein damage is detected by measuring a potential difference of the test body. 13. The electromagnetic force according to claim 1, wherein the test body is a movable body, a reaction force support device is provided, and the test body is placed between the movable body and the reaction force support device to energize the test body. Electromagnetic force load testing device processed by. 14. The electromagnetic force according to claim 1, wherein the test body is a rod-shaped blade, a reaction force support device is provided, and a workpiece is placed between the blade and the reaction force support device to energize the test body. An electromagnetic force load tester that cuts the specimen with.