Method for measuring magnetostriction constant by using multi-beam laser heterodynes

A technology of magnetostriction coefficient and laser heterodyne, applied in the direction of magnetostriction performance measurement, measurement device, magnetic performance measurement, etc., can solve the problem of low precision

Inactive Publication Date: 2012-01-18
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In order to solve the problem of low precision of the existing method for measuring the magnetostriction coefficient, the present invention prov

Method used

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  • Method for measuring magnetostriction constant by using multi-beam laser heterodynes
  • Method for measuring magnetostriction constant by using multi-beam laser heterodynes
  • Method for measuring magnetostriction constant by using multi-beam laser heterodynes

Examples

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Example Embodiment

[0061] Specific Embodiment 1. The method for measuring hysteresis coefficient by multi-beam laser heterodyne described in this embodiment is realized based on the following device, which can be found in figure 1 As shown, the device includes two fixed rods 1-1, 1-2 of the same shape, excitation coil 2, DC stabilized power supply 4, plane mirror 5, thin glass plate 6, polarizing beam splitter PBS7, H 0 Solid-state laser 8, quarter-wave plate 9, vibrating mirror 10, converging lens 11, photodetector 12 and signal processing system 13,

[0062] The DC stabilized power supply 4 is used to provide working power to the excitation coil 2, so that the excitation coil 2 generates a magnetic field, the test piece 3 is placed in the center in the cylindrical space formed by the excitation coil 2, and one end of the test piece 3 is fixedly connected to a One end of the fixed rod 1-1, the other end of the fixed rod 1-1 is fixed, the other end of the test piece 3 is fixed to one end of anot...

Example Embodiment

[0079] Specific embodiment two, this embodiment is a further limitation of the method for multi-beam laser heterodyne measurement of the hysteresis coefficient described in specific embodiment one, in this embodiment, according to the electrical signal output by the photodetector 12 to obtain the The process of the length variation Δl of the part 3 is: the photocurrent signal sent by the photodetector 12 received by the signal processing system 13 is I, and the expression of the photocurrent signal I is:

[0080] I = ηe hv 1 Z ∫ ∫ S 1 2 [ E 1 ( t ) + E 2 ( t ) + · · · + ...

Example Embodiment

[0118] Specific implementation mode three, this implementation mode is a specific embodiment of the method for multi-beam laser heterodyne measurement of hysteresis expansion coefficient according to the present invention:

[0119] In this embodiment, MATLAB is used to simulate and measure the magnetostriction coefficient of a 200 mm-long iron-nickel alloy sample thin glass plate. H used o The wavelength λ=2050nm of the laser light that solid-state laser device 8 sends; Exciting coil 2 is 200 turns / cm; The refractive index of medium between plane mirror 5 and thin glass plate 6 gets n=1; =1mm, the sensitivity of the detector 12 is 1A / W. The vibration equation x(t)=a(t of the vibrating mirror 10 2 / 2), take a=2×10 3 m / s 2 . During the experiment, it was ensured that the current applied to the exciting coil 2 would not be magnetically saturated.

[0120] It can be seen from the simulation that the Fourier transform spectrum of the multi-beam laser heterodyne signal obtaine...

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Abstract

The invention discloses a method for measuring magnetostriction constant by using multi-beam laser heterodynes, which relates to a method for measuring the magnetostriction constant of a material and is used for solving the problem of low precision in a traditional method for measuring the magnetostriction constant. The measuring method disclosed by the invention comprises the following steps of: firstly, carrying out alternating-current demagnetization on a piece to be tested and fixing the piece between two fixed rods; then turning on an H0 solid laser and driving a galvanometer scanner to start working; and finally, applying monotonically-raised direct current on the piece to be tested, wherein in the process of applying the current, a signal processing system is adopted to continuously acquire an electrical signal output by a photoelectric detector, acquire a length variation delta l of the piece to be tested and acquire the magnetostriction constant alpha equal to delta l/l according to the delta l. According to the method disclosed by the invention, on the basis of a laser heterodynes technology and a Doppler effect, length information to be tested is loaded in a frequency difference of a heterodynes signal and is demodulated by the signal to simultaneously obtain a plurality of length values to be tested; and the measurement precision of the length value to be tested can be improved by weighted average processing, and further, the measurement precision of the magnetostriction constant is improved.

Description

technical field [0001] The invention relates to a measuring method, in particular to a measuring method of the hysteresis expansion coefficient of a material. Background technique [0002] The magnetic domains of ferromagnets will be oriented under the action of an external magnetic field, which will cause the change of the lattice spacing in the medium, and the phenomenon that the length of the ferromagnet will change is called the magnetostrictive effect. Discovered in 1999, it is also called the Joule effect. Magnetostriction not only has an important influence on the magnetism of materials, especially on the initial permeability, coercive force, etc., but also the effect itself is widely used in practice, such as: magnetostriction technology can be used for mechanical vibration And ultrasonic transducers, there are also important applications in lidar and other aspects. [0003] Ultrasonic generators and receivers can be made by using the length change of materials und...

Claims

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Application Information

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IPC IPC(8): G01R33/18G01B11/02
Inventor 李彦超王春晖
Owner HARBIN INST OF TECH
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