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CN-116482589-B - Sheet in-situ magnetic characteristic test method

CN116482589BCN 116482589 BCN116482589 BCN 116482589BCN-116482589-B

Abstract

The invention discloses a method for testing the in-situ magnetic characteristics of a thin plate, which comprises the steps of adjusting the height and angle of a testing device to enable the testing device to be close to a position to be tested of a magnetic shielding body, enabling an auxiliary magnetic yoke with an excitation coil to be close to a testing surface and locking a vacuum chuck, starting a data acquisition program, enabling the magnetic field intensity coil and a magnetic induction intensity probe to be close to the testing surface of the magnetic shielding body under the action of an electric push rod, enabling the excitation coil on the magnetic yoke to be electrified, acquiring a testing graph and testing data on an upper computer through data transmission software and hardware, opening a lock catch of the vacuum chuck after testing is completed, and evacuating the testing device. The invention can realize the in-situ measurement of the magnetic shielding body material, does not need to be disassembled, is convenient for monitoring and maintaining the performance of the magnetic shielding body, and has convenient operation and wide applicability.

Inventors

  • SUN JINJI
  • ZHOU WEIYONG
  • XU XUEPING
  • HAN BANGCHENG

Assignees

  • 北京航空航天大学
  • 北京航空航天大学杭州创新研究院

Dates

Publication Date
20260508
Application Date
20230406

Claims (9)

  1. 1. The testing device comprises a movable base, a lifting support frame, a rotary support, a measuring assembly, a vacuum chuck and a magnetic yoke, wherein the movable base is used for moving the testing device to a position to be tested, the height of the lifting support frame fixedly connected with the movable base and the angle of a rotary support seat hinged with the lifting support frame are adjusted, the measuring posture of the testing device is adjusted, the magnetic yoke is opposite to and close to a thin plate sample, after the magnetic yoke is close to the thin plate sample, the vacuum chuck fixedly connected with the magnetic yoke and the rotary support seat is used for sucking and fixing the testing device and the thin plate sample, and meanwhile, the movable joints of the movable base, the lifting support frame and the rotary support seat are locked, so that the relative positions of the testing device and the thin plate sample in the testing process are kept fixed; after the measuring component reaches the testing position under the pushing of the non-magnetic electric push rod, excitation current is applied to form controllable magnetic flux density in a closed loop formed by the thin plate sample piece through an excitation coil wound on the magnetic yoke, and magnetic field intensity and magnetic induction intensity with different amplitudes are formed in the thin plate sample piece through adjusting the current of the excitation coil, so that the complete hysteresis characteristic of the sample piece is obtained; The method comprises the following steps: Step (1), adjusting the height and angle of the testing device through a movable base, a lifting support frame and a rotary support seat, so that the testing device is close to a sheet sample to be tested; Step (2), the auxiliary magnetic yoke is close to the thin plate sample piece, and the vacuum chuck, the movable base, the lifting support frame and the rotary support seat are locked; Step (3), starting a data acquisition process, wherein the measuring assembly is automatically close to the thin plate sample; step (4) selecting a test mode, and loading current by the exciting coil according to the set test mode; Selecting a target measuring point according to the test requirement, acquiring data through a measuring component, and acquiring a test graph and test data on an upper computer by utilizing data transmission software and hardware; step (6), repeating the steps (1) - (5) according to the test requirements to acquire different test position data of the thin plate sample; and (7) completing the test, and withdrawing the test device.
  2. 2. The method for testing the in-situ magnetic properties of the thin plate according to claim 1, wherein the step (1) comprises moving the testing device to a position to be tested by using the movable base, and adjusting the measuring posture of the testing device by adjusting the height of the lifting support fixedly connected with the movable base and adjusting the angle of the rotating support hinged with the lifting support, so that the magnetic yoke is opposite to and close to the thin plate sample.
  3. 3. The method for testing the in-situ magnetic properties of the thin plate according to claim 2, wherein the step (2) comprises the steps of sucking and fixing the testing device and the thin plate sample by using a vacuum chuck fixedly connected with the magnetic yoke and the rotary support seat after the magnetic yoke is close to the thin plate sample, locking movable joints of the movable base, the lifting support frame and the rotary support seat, ensuring that the relative positions of the testing device and the thin plate sample are kept fixed in the testing process, and forming a closed loop by the magnetic yoke and the thin plate sample after the position of the testing device is locked.
  4. 4. The method for testing the in-situ magnetic properties of the thin plate according to claim 3, wherein in the step (3), the data acquisition flow comprises the steps of pushing the measuring assembly to be close to the thin plate sample piece through a magneto-free push rod, wherein one end of the magneto-free push rod is fixedly connected with the rotary supporting seat, and the other end of the magneto-free push rod is connected with the measuring assembly through bolts, after the measuring assembly reaches a testing position under the pushing of the magneto-free push rod, exciting flow is applied through an exciting coil wound on a magnetic yoke, controllable magnetic flux density is formed in a closed loop formed by the thin plate sample piece, and magnetic field intensity and magnetic induction intensity with different magnitudes are formed in the thin plate sample piece through adjusting the current of the exciting coil, so that the complete hysteresis property of the thin plate sample piece is obtained.
  5. 5. The method for testing the in-situ magnetic properties of the thin plate according to claim 4, wherein in the step (4), the test mode comprises a direct current mode or an alternating current mode, wherein the direct current mode is used for obtaining the direct current magnetic properties of the thin plate sample piece with the amplitude within 200kA, the alternating current mode is used for obtaining the alternating current magnetic properties of the thin plate sample piece with the frequency range of 20 Hz-20 kHz, the exciting current is input into pulse waveforms with different amplitudes or continuously increased or decreased waveforms are used, in the alternating current mode, different hysteresis properties of the thin plate sample piece are obtained by adjusting the frequency of the exciting current of the exciting coil, and the number of turns of the exciting coil is 200-300 turns.
  6. 6. The method according to claim 5, wherein in the step (5), the target measuring points of the sheet sample are selected from the group consisting of a sheet sample having a size of 400mm×400mm, a minimum measuring area of the measuring unit being 50mm×50mm, and a measuring point pitch on the sheet sample being 50mm or more, and the measuring points are selected from the group consisting of a distance of 50mm or more from the edge considering a magnetic excitation uniform region in the sheet sample, and a maximum measuring point arrangement being 6×6=36 for the sheet sample having a size of 400mm×400 mm.
  7. 7. The method for testing the in-situ magnetic characteristics of the thin plate according to claim 6, wherein the measuring assembly in the step (5) comprises a measuring base, a magnetic induction probe and a magnetic field intensity coil, the magnetic induction probe and the magnetic field intensity coil are fixedly connected with the measuring base, magnetic signals are acquired by being close to a thin plate sample piece under the driving of a magneto-free push rod, and a needle of the magnetic induction probe is contacted with the thin plate sample piece to shrink under the driving of the magneto-free push rod to form an electric conduction path, so that potential differences among touch points are obtained, and the magnetic induction intensity among the test points is further calculated.
  8. 8. The method for testing the in-situ magnetic properties of the thin plate according to claim 7, wherein the magnetic field strength coil comprises two layers stacked on each other, each layer is wound by two groups of first coils and second coils which are perpendicular to each other, and the magnetic field strength of the thin plate sample in two perpendicular directions is respectively obtained; From the electromagnetic induction, the magnetic field strength of the magnetic field strength coil H 1 near the sheet sample was calculated as follows: ; Wherein: -vacuum permeability; -number of turns of field strength coil windings; -cross-sectional area of perpendicular magnetic flux density within the field strength coil; -an electromotive force is induced inside the magnetic field strength coil; The magnetic field intensity H 2 is obtained according to the test of the other layer of coil far away from the magnetic field intensity, and the magnetic field intensity H 0 in the sheet sample piece after correction is obtained according to the linear relation of the magnetic field intensity as follows: ; Wherein: -magnetic field strength measured by a magnetic field strength coil in proximity to the test sample; -distance of the magnetic field strength coil close to the test sample from the sheet sample; -magnetic field strength of magnetic field strength coil test remote from the sheet sample; -distance of the field strength coil from the sheet sample.
  9. 9. The method for testing the in-situ magnetic properties of a thin plate according to claim 7, wherein the magnetic induction intensity is calculated according to the electromagnetic induction principle as follows: ; Wherein: -the magnetic induction probe test position and the cross-sectional area formed by the sample; -induced electromotive force detected by the magnetic induction probe.

Description

Sheet in-situ magnetic characteristic test method Technical Field The invention relates to the field of soft magnetic material testing, in particular to a method for testing in-situ magnetic properties of a thin plate. Background By utilizing the high magnetic permeability of the soft magnetic material, most direct current and low frequency magnetic fields in the environment can be locked into the soft magnetic material through the shunt effect, so that after a closed magnetic shielding body structure is established by the soft magnetic material, a high-performance near-zero magnetic space can be obtained in the closed structure, and the constructed near-zero magnetic space can be used as a basic condition for ultra-high sensitivity measurement, deep space deep detection, basic physical research and the like, and therefore, the soft magnetic material has an important role in the magnetic shielding field. The magnetic properties such as magnetic permeability, coercive force, saturation induction intensity and the like of the soft magnetic material directly determine the magnetic shielding performance, so that how to accurately, rapidly and comprehensively test and judge the magnetic properties of the soft magnetic material has important significance. In general, a specially-made standard test ring is adopted in a magnetic property test method of a soft magnetic material, an excitation coil and a test induction coil are uniformly and densely wound on the test ring, the magnetic field intensity H and the corresponding magnetic induction intensity B are obtained by utilizing electromagnetic induction, and a complete hysteresis loop of the material is obtained by forward and reverse excitation, so that the magnetic property of the material can be calculated. The testing method has the defects that 1) a special standard test ring is needed, the performance of the sheet material for actual installation cannot be directly reflected, 2) winding is needed for each test, the testing efficiency is low, and human stress errors are introduced. In the current development of magnetic property testing methods for soft magnetic materials, gmyrek et al use high magnetic conductive materials to make yokes, combined with test samples, and extended into a closed loop (Gmyrek Z.Single Sheet Tester With Variable Dimensions[J].IEEE Transactions on Instrumentation&Measurement,2016,65(7):1661-1668). so that the magnetic properties of the flat sample can be directly obtained by installing induction coils on the flat sample for constructing shields (no separate special test rings are required). However, the improved testing method still has certain defects that 1) the improved testing method still needs to wind magnetic induction coils, the problems of low testing efficiency and introduction of human errors cannot be solved, 2) the whole average magnetic performance on a flat plate can be tested, the magnetic performance of a local area cannot be obtained, the defects cannot be positioned, and 3) in-situ measurement cannot be carried out on the installed shielding body, namely the magnetic performance of the built material cannot be estimated. Disclosure of Invention Aiming at the defects of the prior art method, the invention provides a method for testing the magnetic properties of a sheet in situ, which realizes the magnetic properties of the material of a shielding body after the construction is completed, and can change the excitation direction of a magnetic field by applying the magnitude of a two-dimensional magnetic field, thereby realizing the complete magnetic property measurement of a sheet sample, and simultaneously, the testing of different shielding structures (such as a flat plate, an arc panel and the like) can be realized by fine adjustment of a testing structure. The aim of the invention is achieved by the following technical scheme: a method for testing the in-situ magnetic properties of a thin plate comprises the following steps: Step (1), adjusting the height and angle of the testing device through a movable base, a lifting support frame and a rotary support seat, so that the testing device is close to a sheet sample to be tested; Step (2), the auxiliary magnetic yoke is close to the thin plate sample piece, and the vacuum chuck, the movable base, the lifting support frame and the rotary support seat are locked; Step (3), starting a data acquisition process, wherein the measuring assembly is automatically close to the thin plate sample; step (4) selecting a test mode, and loading current by the exciting coil according to the set test mode; Selecting a target measuring point according to the test requirement, acquiring data through a measuring component, and acquiring a test graph and test data on an upper computer by utilizing data transmission software and hardware; step (6), repeating the steps (1) - (5) according to the test requirements to acquire different test position data of the thin plate sample; and (7) co