CN103576107A - Method and device for measuring integrated magnetostriction coefficient - Google Patents

Abstract

The invention discloses a method and device for measuring the integrated magnetostriction coefficient and belongs to the technical field of material performance detection. According to the method, an original capacitance sensor measuring mechanism is improved, the integrated magnetostriction coefficient of materials is measured directly through a capacitance sensor, and a magnet field provided by a solenoid is free of remaining magnetism and large in an even area. A detected sample (3) changes in length along with changes of the magnet field so as to change the distance between a capacitor sensor pole plate A (21) and a capacitor sensor pole plate (B). The capacitance sensor (2) detects the changes of the distance between the pole plates so as to further obtain the magnetostriction coefficient. The method and device have the advantages that the solenoid is used for applying the magnet field, so that the problems of poor evenness and remaining magnetism are effectively avoided; the capacitor sensor is used for measuring the magnetostriction coefficient, so that high-precision measurements of the magnetostriction coefficient of the detected sample can be completed; non-magnetic materials are used for making a pressure rod, so that the influence of the pressure rod on the evenness of the magnet field is reduced; operation is simple, so that operators can measure conveniently.

Description

A kind of method and device thereof of measuring whole magnetostriction coefficient

Technical field

The invention belongs to material property detection technique field, relate to a kind of method and device thereof of measuring whole magnetostriction coefficient.

Background technology

From the intellectual material concept proposition eighties in 20th century, such Material Physics mechanism, preparation technology and the aspects such as application in intelligent system and structure thereof become rapidly study hotspot.And the magnetostriction materials that occupy critical role in intellectual material are classes can perception external magnetic field variation produce the material of self change in size.The sign of magnetostriction materials performance quality illustrates by magnetostriction coefficient λ, axially the applying after magnetic field H of the bar-shaped magnetostriction materials that are L along length, the elongation of material production Δ L, definition Δ L/L=λ.

At present, the method for measurement magnetostriction coefficient mainly contains electric resistance strain film method, capacitance method, electric vortex method, optical interferometry, optical lever method etc.Production unit mainly adopts in one's power is electric resistance strain film method in present vast Research Center, this method is to utilize magnetostriction distortion to cause resistance strain gage distortion, and resistance strain gage distortion must bring resistance variations, by measuring resistance, just change and can indirectly obtain magnetostriction coefficient.This method is simple in structure, easy to use, highly sensitive, and measuring speed is fast, can realize multimetering and test process automation, and technique comparative maturity, is convenient to choice and operation.But electric resistance strain film method also exists certain deficiency, being mainly manifested in resistance strain gage must well bond together with sample, and how many meetings of bonding agent affect measurement result; Welding, the length of resistance strain gage lead-in wire can affect measurement result; Resistance strain gage is mainly measured local train, and actual use is mainly whole use.Capacitance method is the variation of measuring the two capacitor plate spacing that the length variations of magnetostriction materials causes, length variations is converted into capacitance variations, and it has, and highly sensitive, frequency response is fast, good stability, output signal are directly changed into electric weight, it is contactless to be measured as, do not produce the features such as dynamometry distortion, whole measurement.But during capacitance measurement, need to guarantee that pole plate is parallel, this there are certain requirements sample clamp.Electric vortex method utilizes current vortex sensor after exciting curent frequency and measured conductor (magnetostriction materials) are determined, the size of its oscillatory circuit output only changes with the gap variation of end face and measured object, and the electric signal of exporting by measurement just can calculate magnetostriction coefficient.Advantage and the capacitance method of electric vortex method are basic identical, but because it is more subject to the impact of changes of magnetic field, are generally only suitable for surveying static magnetostriction.Optical lever method utilizes magnetostriction to cause that spot displacement changes, and by detecting facula position, obtains magnetostriction coefficient.Although this method structure is simple, the installation of sample is inconvenient, stricter to environmental requirement.Optical interferometry is also a kind of non-contact measurement, utilizes the interference of beam of laser to may detect the minimum displacement for 1nm.But this method sample is installed and the adjustment of light path is very inconvenient, to operator's experimental skill, requires higher.

Magnetostriction measurement equipment suitable magnetostriction coefficient checkout equipment, also needs magnetic field that equipment is provided except selecting.At present, provide the major way in magnetic field to have two kinds: electromagnet and solenoid.Electromagnet in use, need to be placed between two yokes measuring sample, and sample length will affect space length between two yokes.And space length is different, magnetic field homogeneity is different.Long sample the inhomogeneous of its Surface field when measuring will affect measurement result.Meanwhile, after long-term use, electromagnet core is had remanent magnetism by remagnetization and exists.Solenoid simple structure, easy to use, after energising, in solenoid, produce axial magnetic field, and intensity and the sexual intercourse of electric current retention wire, can there is in solenoid central area very long homogeneity range.But after energising, there is the problem that thermal value is large, in long-time use procedure, will note heat radiation.Meanwhile, perhaps also has the impact of electromagnetic radiation.

Summary of the invention

The present invention is directed in current magnetostriction measurement method: strain gauge method cannot be measured whole magnetostriction; Although additive method can be measured whole magnetostriction, exist device structure complicated, operator is required to the problems such as high; Electromagnet cannot provide large uniform magnetic field scope, has the problems such as remanent magnetism phenomenon, and a kind of method and device thereof of measuring whole magnetostriction coefficient is provided.

The method of whole magnetostriction coefficient and a device thereof, concrete measuring process is:

1. sample is installed.Detected sample 3 is placed in the middle of capacitive transducer pole plate A21 and capacitive transducer pole plate B22.

2. regulate on demand pressure to apply and transport platform 5, by press rods 4 detected sample 3 stress applications.

3. capacitive transducer 2 positions are adjusted: front and back control capacittance sensor 2 is in the position of capacitive transducer pole plate A21, with the length variations that guarantees to cause because of detected sample 3 in measuring process in capacitive transducer 2 measurement ranges.

4. with pressure, apply and transport platform 5 pushes solenoid homogeneity range 11 centre positions along conveying 6 by detected sample 3.

5. give solenoid coil 12 power supplies, the magnetostriction that capacitive transducer 2 detects detected sample 3 changes, and completes magnetostriction measurement.

Adopt solenoid 1 that electromagnetic field is provided, the electromagnetic intensity providing is determined by the strength of current I and the coil turn n that pass into wherein, maximum length in conjunction with detected sample 3 need to be determined solenoid homogeneity range 11, and detected sample 3 length need to be less than solenoid homogeneity range 11 length.The calculating of electromagnetic intensity H can be with reference to formula:

$H=\frac{\mathrm{nI}}{4L(r_2-r_1)}[(L+x)1\mathrm{<figure-callout\; id="2"\; label="n\; r"\; filenames="HDA0000401933020000012.png,HDA0000401933020000021.png"\; state="\{\{state\}\}">n</figure-callout>}\frac{r_{}}{}\frac{{}_2+\sqrt{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA0000401933020000012.png,HDA0000401933020000021.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^2+{(L+x)}^2}}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000401933020000011.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+\sqrt{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000401933020000011.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2+{(L+x)}^2}}+(L-x)1\mathrm{<figure-callout\; id="2"\; label="n\; r"\; filenames="HDA0000401933020000012.png,HDA0000401933020000021.png"\; state="\{\{state\}\}">n</figure-callout>}\frac{r_{}}{}\frac{{}_2+\sqrt{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA0000401933020000012.png,HDA0000401933020000021.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^2+{(L-x)}^2}}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000401933020000011.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+\sqrt{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000401933020000011.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2+{(L-x)}^2}}],$

Wherein H be in solenoid apart from central point the magnetic field intensity apart from x place, 2L is solenoid length, 2r ₁for solenoid coil internal diameter, 2r ₂for solenoid coil external diameter, design spiral pipeline circle 12 accordingly.For preventing that solenoid 1 duration of work from producing heat and causing self and the 11 temperature rising impacts of solenoid homogeneity range to use, can in solenoid coil 12, add circulating water line system.

Pressure applies and transport platform 5 exert pressure to detected sample 3 by press rods 4, with fixing detected sample 3 and measure its Magnetostriction under certain pressure.The material of press rods 4 need be manufactured by nonmagnetic substance.Pressure applies and transport platform 5 can be moved along conveying 6, and detected sample 3 is placed into solenoid homogeneity range 11 centre positions.

Detected sample 3 is placed in the middle of capacitive transducer pole plate A21 and capacitive transducer pole plate B22, and is placed on solenoid homogeneity range 11 centre positions while measuring.Capacitive transducer 2 is fixed on capacitive transducer pole plate A21.During measurement, follow the variation in magnetic field, detected sample 3 length variations change capacitive transducer pole plate A21 and capacitive transducer pole plate B22 spacing, the capacitive transducer 2 being fixed on capacitive transducer pole plate A21 can detect this variation, and output electrical signals, known magnetostriction coefficient after conversion.

The material that press rods 4 adopts is nonmagnetic substance, is preferably magnetism-free stainless steel.

The invention has the beneficial effects as follows:

1. adopt solenoid to apply magnetic field, effectively avoid the problems such as electromagnet magnetic field homogeneity is poor, remanent magnetism.

2. adopt capacitive transducer to measure magnetostriction coefficient, can complete the high-acruracy survey of the whole magnetostriction coefficient of detected sample.

3. adopt nonmagnetic substance to make press rods, avoided the impact of press rods on magnetic field homogeneity.

4. simple to operate, convenient operation person measures.

Accompanying drawing explanation

Fig. 1 is solenoid schematic diagram of the present invention.

In figure: 1--solenoid, 11--solenoid homogeneity range, 12--solenoid coil.

Fig. 2 is whole test desk schematic diagram of the present invention.

2--capacitive transducer, 21--capacitive transducer pole plate A, 22--capacitive transducer pole plate B, 3--detected sample, 4--press rods, 5--pressure applies and transport platform, 6--conveying.

Fig. 3 is the Tb of <110> orientation _0.27dy _0.73fe _1.95whole magnetostriction coefficient.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is further described, but not as a limitation of the invention.

1. sample is installed.This material of measuring sample is the Tb of <110> orientation _0.27dy _0.73fe _1.95, length is 60mm, diameter is 12mm.Detected sample (3) is placed on capacitive transducer pole plate A(21) and capacitive transducer pole plate B(22) in the middle of.

2. regulate on demand pressure to apply and transport platform (5), by press rods (4) detected sample (3) stress application, this gaging pressure is 20MPa.

3. capacitive transducer (2) position is adjusted.Before and after control capacittance sensors (2) at capacitive transducer pole plate A(21) position, with the length variations that guarantees to cause because of detected sample (3) in measuring process in capacitive transducer (2) measurement range.

4. with pressure, apply and transport platform (5) pushes solenoid homogeneity range (11) centre position along conveying (6) by detected sample (3).

5. give solenoid coil (12) power supply, the magnetostriction that capacitive transducer (2) detects detected sample (3) changes, and completes magnetostriction measurement.As shown in Figure 2, Fig. 2 is the result of three independent measurement same material magnetostriction coefficients to concrete measurement result.Visible this method can realize the whole magnetostriction coefficient of high-acruracy survey material.

Claims (6)

1. measure method and the device thereof of whole magnetostriction coefficient, it is characterized in that improving original capacitive transducer measuring mechanism, utilize capacitive transducer directly to measure the whole magnetostriction coefficient of material; Solenoid can be large without remanent magnetism, homogeneity range for the magnetic field that experiments of measuring provides simultaneously; Concrete measuring process is as follows:

1). sample is installed: detected sample (3) is placed on capacitive transducer pole plate A(21) and capacitive transducer pole plate B(22) in the middle of;

2). regulate on demand pressure to apply and transport platform (5), by press rods (4) detected sample (3) stress application;

3). capacitive transducer (2) position is adjusted: front and back control capacittance sensors (2) are at capacitive transducer pole plate A(21) position, with the length variations that guarantees to cause because of detected sample (3) in measuring process in capacitive transducer (2) measurement range;

4). with pressure, apply and transport platform (5) pushes solenoid homogeneity range (11) centre position along conveying (6) by detected sample (3);

5). give solenoid coil (12) power supply, the magnetostriction that capacitive transducer (2) detects detected sample (3) changes, and completes magnetostriction measurement.

2. method and the device thereof of the whole magnetostriction coefficient of measurement according to claim 1, is characterized in that: the material that press rods (4) adopts is nonmagnetic substance, and preferably a kind of material is magnetism-free stainless steel.

3. method and the device thereof of the whole magnetostriction coefficient of measurement according to claim 2, is characterized in that: the nonmagnetic substance that press rods (4) adopts is magnetism-free stainless steel.

4. method and the device thereof of the whole magnetostriction coefficient of measurement according to claim 1, it is characterized in that: capacitive transducer (2) is fixed on capacitive transducer pole plate A(21) on, detected sample (3) length variations changes capacitive transducer pole plate A(21) and capacitive transducer pole plate B(22) spacing, be fixed on capacitive transducer pole plate A(21) on capacitive transducer (2) this variation can be detected, and output electrical signals, known magnetostriction coefficient after conversion.

5. method and the device thereof of the whole magnetostriction coefficient of measurement according to claim 1, it is characterized in that: adopt solenoid (1) that electromagnetic field is provided, the electromagnetic intensity providing is determined by the strength of current I and the coil turn n that pass into wherein, in conjunction with the maximum length of detected sample (3), need to determine solenoid homogeneity range (11), detected sample (3) length need to be less than solenoid homogeneity range (11) length; The computing formula of electromagnetic intensity H is:

$H=\frac{\mathrm{nI}}{4L(r_2-r_1)}[(L+x)1n\frac{r_2+\sqrt{r_2^2+{(L+x)}^2}}{r_1+\sqrt{r_1^2+{(L+x)}^2}}+(L-x)1n\frac{r_2+\sqrt{r_2^2+{(L-x)}^2}}{r_1+\sqrt{r_1^2+{(L-x)}^2}}],$

Wherein H be in solenoid apart from central point the magnetic field intensity apart from x place, 2L is solenoid length, 2r ₁for solenoid coil internal diameter, 2r ₂for solenoid coil external diameter, design spiral pipeline circle (12) accordingly.

6. method and the device thereof of the whole magnetostriction coefficient of measurement according to claim 1, it is characterized in that: for preventing that solenoid (1) duration of work from producing heat and causing self and solenoid homogeneity range (11) temperature rising impact to use, in solenoid coil (12), add circulating water line system.

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