CN108051648B - A kind of material electromagnetic attributes measurement method based on DC potential and detection method of eddy - Google Patents
A kind of material electromagnetic attributes measurement method based on DC potential and detection method of eddy Download PDFInfo
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- CN108051648B CN108051648B CN201711258187.5A CN201711258187A CN108051648B CN 108051648 B CN108051648 B CN 108051648B CN 201711258187 A CN201711258187 A CN 201711258187A CN 108051648 B CN108051648 B CN 108051648B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/022—Measuring gradient
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Abstract
A kind of material electromagnetic attributes measurement method based on DC potential and detection method of eddy, this method experimental provision are made of DC potential subtraction unit and EDDY CURRENT subtraction unit；When realizing this method, test specimen is given to apply constant current excitation by the constant-current source in DC potential subtraction unit first, with nanovoltmeter collection voltages signal, by the conductivity that can be calculated test specimen；Then applied by the excitation coil in EDDY CURRENT subtraction unit to test specimen and motivated, then detect voltage signal with detection coil；Since the voltage signal of detection coil and the conductivity and magnetic conductivity of test specimen are related, so the magnetic conductivity of material can be acquired by conjugate gradient method inverting to vortex detecting signal under the premise of measuring test specimen conductivity by dc-bit method；Compared to the measurement method of traditional test specimen conductivity and magnetic conductivity, the method for the present invention can achieve the purpose that while measure magnetic material conductivity and magnetic conductivity, and driving frequency is adjustable, is with a wide range of applications.
Description
Technical field
The present invention relates to based on electromagnetic method magnetic material conductivity measurement and permeability measurement field, and in particular to one
Material electromagnetic attributes measurement method of the kind based on DC potential and detection method of eddy.
Background technique
Magnetic material is one of mainstay material of modern industrial and agricultural production, and the product of magnetic material is to indicate a state
The index of family's economic development level, demand can then embody roughly a national national life level.As a kind of basic function
Can material, magnetic material application in the every aspect of life, at present magnetic material be mainly used in telecommunications, motor, television set and
Storage equipment of computer etc., it has been increasingly becoming the critical material to promote social development, so to its electromagnetic parameter
Measurement is particularly important.The measurement method of magnetic material conductivity mainly has dc-bit method and alternating current bridge method etc. at present,
Permeability measurement method mainly has ballistic galvanometer method, fluxmeter method, nuclear magnetic resonance method and Hall effect method etc..
Dc-bit method is measurement one of most common method of material electric conductivity, it be widely used in plastic deformation detection,
Fatigue damage detection, macroscopic cracking detection etc..Dc-bit method easy, easy to operate, high sensitivity with system building
The advantages that short with time of measuring, so it can conveniently precise measurement magnetic material conductivity.
Coil is not required to directly contact with measured object when EDDY CURRENT, can carry out high speed detection, it is easy to accomplish automation, and whirlpool
The conductivity and magnetic conductivity of voltage signal and measured material that coil is detected in stream detection are related.It has been investigated that logical first
After crossing the conductivity that dc-bit method measures material, coil can be detected from EDDY CURRENT by the method for conjugate gradient method inverting
Voltage signal in obtain the magnetic conductivity of material, be finally reached measurement magnetic material conductivity and magnetic conductivity purpose.
Summary of the invention
In order to achieve the purpose that above-mentioned measurement magnetic material conductivity and magnetic conductivity, the purpose of the present invention is to provide one kind
Material electromagnetic attributes measurement method based on DC potential and detection method of eddy, this method experimental provision is by DC potential subtraction unit
It is formed with EDDY CURRENT subtraction unit.DC potential subtraction unit is by constant-current source, nanovoltmeter, scan table, data acquisition device and four
Probe composition, wherein constant-current source and (1) number, (4) number two probes are connected, give its application constant current, nanovoltmeter and (2) number,
(3) number two probes are connected, and measure the voltage between it, data acquisition device is connected with scan table, nanovoltmeter.EDDY CURRENT side
Subtraction unit is made of signal generator, power amplifier, lock-in amplifier, data acquisition device, excitation coil and detection coil,
Wherein signal generator is connected with power amplifier, lock-in amplifier, and excitation coil is connected with power amplifier, detection coil with
Lock-in amplifier is connected, and data acquisition device is connected with lock-in amplifier, by signal generator, power amplifier to excitation line
Circle applies sinusoidal signal excitation, then the voltage signal of detection coil is acquired with lock-in amplifier.It, first will be to when realizing this method
Test block is placed on scan table, and four probes are placed in test specimen upper surface, is applied with constant-current source to two of them probe
Constant current, with nanovoltmeter measurement other two probe between voltage, by the collected voltage signal of data acquisition device,
The conductivity of test specimen can be calculated in the current signal of constant-current source output and the size of test specimen；Then pass through signal generator, function
Rate amplifier applies sinusoidal signal excitation to excitation coil, then the voltage signal of detection coil is acquired with lock-in amplifier；Due to
The conductivity and magnetic conductivity of the voltage signal and test specimen that detect coil are related, so measuring test specimen by dc-bit method
The magnetic conductivity of material can be acquired under the premise of conductivity by conjugate gradient method inverting to vortex detecting signal.Compared to biography
The test specimen conductivity of system and the measurement method of magnetic conductivity, the method for the present invention can reach while measure magnetic material conductivity and magnetic conductance
The purpose of rate, and the detection sensitivity of the method for the present invention is high, driving frequency is adjustable, detection system is easy to build and maturation can
It leans on, is with a wide range of applications.
To achieve the above objectives, the present invention adopts the following technical scheme:
A kind of material electromagnetic attributes measurement method based on DC potential and detection method of eddy, includes the following steps:
Step 1: building experimental provision, which is made of DC potential subtraction unit and EDDY CURRENT subtraction unit, directly
Galvanic electricity position subtraction unit is by constant-current source, nanovoltmeter, scan table, data acquisition device and four probe groups being arranged on scan table
At four probes respectively are No. 1 probe, No. 2 probes, No. 3 probes and No. 4 probes, wherein constant-current source and No. 1 probe and 4
Number probe is connected, its is given to apply constant current, and nanovoltmeter is connected with No. 2 probes and No. 3 probes, measures the voltage between it, several
It is connected according to acquisition device with scan table, nanovoltmeter；Eddy current detection method device is put by signal generator, power amplifier, locking phase
Big device, data acquisition device, excitation coil and detection coil composition, wherein signal generator and power amplifier and locking phase are amplified
Device is connected, and excitation coil is connected with power amplifier, and detection coil is connected with lock-in amplifier, and data acquisition device is put with locking phase
Big device is connected, and applies sinusoidal signal excitation to excitation coil by signal generator, power amplifier, then adopted with lock-in amplifier
The voltage signal of collection detection coil；
Step 2: test specimen being processed into the plate test coupon that length is greater than thickness, and the plate test coupon that will be processed first
It is fixed on scan table；On the central axes of plate test coupon equidistantly fix dc-bit method four probes, and ensure probe with
The distance between probe is greater than the width and thickness of plate test coupon；Then applied with constant-current source to No. 1 probe and No. 4 probes constant
Electric current, while recording with nanovoltmeter the variation of voltage between No. 2 probes and No. 3 probes；Finally n group number is acquired with data acquisition device
The conductivity for obtaining plate test coupon is calculated according to and with formula (1-1)；
In formula: σ is the conductivity of plate test coupon, and ρ is the resistivity of plate test coupon, and I is the electric current of constant-current source output, S 2
The distance between number probe and No. 3 probes, UiFor the electricity between No. 2 probes and No. 3 probes of the acquisition of data acquisition device i-th
Pressure, W, H are respectively the width and thickness of plate test coupon, and n is the data group number of acquisition, and i indicates the acquisition of Current data acquisition device
The group number of data is numbered；
Step 3: placing the excitation coil and detection coil of detection method of eddy first above plate test coupon, and utilize signal
Generator generates the sinusoidal excitation signal of predeterminated frequency, amplifies the sinusoidal excitation signal by power amplifier and is applied to excitation
Coil；Then pass through the voltage signal of the amplified detection coil of lock-in amplifier locking phase, detection with data acquisition device acquisition
Shown in the calculation formula such as formula (1-2) of the voltage signal V of coil,
J in formulaeFor the vortex density in plate test coupon, EsFor the electric field strength of ource electric current field, respectively by formula (1-3) and formula
(1-4) is calculated；IpFor the electric current for flowing through detection coil, cond. indicates area of space locating for detection coil；
Je=-j ω σ Ar (1-3)
ω is the angular frequency of sinusoidal excitation signal in formula, and σ is the conductivity of plate test coupon, ArIt is arrow relevant to vortex field
Measure magnetic potential；
Wherein σ is the conductivity of plate test coupon, and μ is the magnetic conductivity of plate test coupon, AsIt is electric with the excitation in excitation coil
Flow relevant vector magnetic potential；
Step 4: the voltage signal V of the detection coil measured in step 3 by eddy current testing device and the conductance of plate test coupon
Rate σ is related with magnetic permeability μ, and the conductivityσ of plate test coupon can be measured by the dc-bit method in step 2, then plate test coupon
Magnetic permeability μ is obtained by the voltage signal V to detection coil using conjugate gradient method inverting.
Compared to the prior art, advantages of the present invention is as follows:
1) the material electromagnetic attributes measurement method based on DC potential and detection method of eddy that the invention proposes a kind of, with biography
System measurement method is compared, and the method for the present invention can measure the conductivity and magnetic conductivity of magnetic material simultaneously；
2) compared with the conductivity of traditional magnetic material and permeability measurement method, the excitation coil of the method for the present invention swashs
Encourage that frequency is adjustable, when the parameter of magnetic characteristic of especially ferrimagnet changes with driving frequency, this method can measure different frequency
The permeability characteristics of lower ferrimagnet；In addition, the detection sensitivity of the method for the present invention is higher, experimental system builds simplicity, behaviour
Make simply, to be with a wide range of applications.
Detailed description of the invention
Fig. 1 is the dc-bit method system and each component connection schematic diagram of eddy detection system applied in the present invention；
Fig. 2 illustrates for the position of excitation coil and detection coil in test specimen schematic diagram used in the present invention and EDDY CURRENT
Figure.
Specific embodiment
The present invention is described in further details with reference to the accompanying drawings and detailed description:
For test specimen as shown in Figure 2, the detecting step of the method for the present invention are as follows: the reality that this method as shown in Figure 1 uses
Experiment device is made of DC potential subtraction unit and EDDY CURRENT subtraction unit.DC potential subtraction unit is by constant-current source, nanovoltmeter, scanning
Platform, data acquisition device and four probes composition, connection type as shown in Figure 1 is by constant-current source and No. 1 probe and No. 4 probe phases
Even, apply constant current to it, nanovoltmeter is connected with No. 2 probes and No. 3 probes, measures the voltage between it, data acquisition dress
It sets and is connected with scan table, nanovoltmeter.Eddy current detection method device is by signal generator, power amplifier, lock-in amplifier, data
Acquisition device, excitation coil and detection coil composition, wherein signal generator is connected with power amplifier and lock-in amplifier, swashs
Coil to be encouraged to be connected with power amplifier, detection coil is connected with lock-in amplifier, and data acquisition device is connected with lock-in amplifier,
Apply sinusoidal signal excitation to excitation coil by signal generator, power amplifier, then acquires detection line with lock-in amplifier
The voltage signal of circle.
When realizing this method, test specimen to be measured is placed on scan table first, and four probes are placed in table on test specimen
Face applies constant currents to wherein No. 1 probe and No. 4 probes with constant-current source, with nanovoltmeter measure No. 2 probes and No. 3 probes it
Between voltage, the current signal and the size of test specimen exported by the collected voltage signal of data acquisition device, constant-current source can
The conductivity of test specimen is calculated；Then sinusoidal signal excitation is applied to excitation coil by signal generator, power amplifier,
The voltage signal of detection coil is acquired with lock-in amplifier again；Due to the voltage signal of detection coil and the conductivity of test specimen
It is related with magnetic conductivity, so can lead to vortex detecting signal under the premise of measuring test specimen conductivity by dc-bit method
Cross the magnetic conductivity that conjugate gradient method inverting acquires material.The present invention is made below with reference to Fig. 1, Fig. 2 specific embodiment further
Detailed description.
A kind of material electromagnetic attributes measurement method based on DC potential and detection method of eddy, includes the following steps:
Step 1: building experimental provision, which is made of DC potential subtraction unit and EDDY CURRENT subtraction unit, directly
Galvanic electricity position subtraction unit is by constant-current source, nanovoltmeter, scan table, data acquisition device and four probe groups being arranged on scan table
At four probes respectively are No. 1 probe, No. 2 probes, No. 3 probes and No. 4 probes, wherein constant-current source and No. 1 probe and 4
Number probe is connected, its is given to apply constant current, and nanovoltmeter is connected with No. 2 probes and No. 3 probes, measures the voltage between it, several
It is connected according to acquisition device with scan table, nanovoltmeter；Eddy current detection method device is put by signal generator, power amplifier, locking phase
Big device, data acquisition device, excitation coil and detection coil composition, wherein signal generator and power amplifier and locking phase are amplified
Device is connected, and excitation coil is connected with power amplifier, and detection coil is connected with lock-in amplifier, and data acquisition device is put with locking phase
Big device is connected, and applies sinusoidal signal excitation to excitation coil by signal generator, power amplifier, then adopted with lock-in amplifier
The voltage signal of collection detection coil；
Step 2: test specimen being processed into the plate test coupon that length is greater than thickness, and the plate test coupon that will be processed first
It is fixed on scan table；On the central axes of plate test coupon equidistantly fix dc-bit method four probes, and ensure probe with
The distance between probe is greater than the width and thickness of plate test coupon；Then applied with constant-current source to No. 1 probe and No. 4 probes constant
Electric current, while recording with nanovoltmeter the variation of voltage between No. 2 probes and No. 3 probes；Finally n group number is acquired with data acquisition device
The conductivity for obtaining plate test coupon is calculated according to and with formula (1-1)；
In formula: σ is the conductivity of plate test coupon, and ρ is the resistivity of plate test coupon, and I is the electric current of constant-current source output, S 2
The distance between number probe and No. 3 probes, UiFor the electricity between No. 2 probes and No. 3 probes of the acquisition of data acquisition device i-th
Pressure, W, H are respectively the width and thickness of plate test coupon, and n is the data group number of acquisition, and i indicates the acquisition of Current data acquisition device
The group number of data is numbered；
Step 3: placing the excitation coil and detection coil of detection method of eddy first above plate test coupon, and utilize signal
Generator generates the sinusoidal excitation signal of predeterminated frequency, amplifies the sinusoidal excitation signal by power amplifier and is applied to excitation
Coil；Then pass through the voltage signal of the amplified detection coil of lock-in amplifier locking phase, detection with data acquisition device acquisition
Shown in the calculation formula such as formula (1-2) of the voltage signal V of coil,
J in formulaeFor the vortex density in plate test coupon, EsFor the electric field strength of ource electric current field, respectively by formula (1-3) and formula
(1-4) is calculated；IpFor the electric current for flowing through detection coil, cond. indicates area of space locating for detection coil；
Je=-j ω σ Ar (1-3)
ω is the angular frequency of sinusoidal excitation signal in formula, and σ is the conductivity of plate test coupon, ArIt is arrow relevant to vortex field
Measure magnetic potential；
Wherein σ is the conductivity of plate test coupon, and μ is the magnetic conductivity of plate test coupon, AsIt is electric with the excitation in excitation coil
Flow relevant vector magnetic potential；
Step 4: the voltage signal V of the detection coil measured in step 3 by eddy current testing device and the conductance of plate test coupon
Rate σ is related with magnetic permeability μ, and the conductivityσ of plate test coupon can be measured by the dc-bit method in step 2, then plate test coupon
Magnetic permeability μ is obtained by the voltage signal V to detection coil using conjugate gradient method inverting.
Claims (1)
1. a kind of material electromagnetic attributes measurement method based on DC potential and detection method of eddy, it is characterised in that: including as follows
Step:
Step 1: building experimental provision, which is made of DC potential subtraction unit and EDDY CURRENT subtraction unit, direct current
Position subtraction unit is made of constant-current source, nanovoltmeter, scan table, data acquisition device and four probes being arranged on scan table, and four
A probe respectively is No. 1 probe, No. 2 probes, No. 3 probes and No. 4 probes, wherein constant-current source and No. 1 probe and No. 4 probes
It is connected, applies constant current to it, nanovoltmeter is connected with No. 2 probes and No. 3 probes, measures the voltage between it, data acquisition
Device is connected with scan table, nanovoltmeter；Eddy current detection method device is by signal generator, power amplifier, lock-in amplifier, number
According to acquisition device, excitation coil and detection coil composition, wherein signal generator is connected with power amplifier and lock-in amplifier,
Excitation coil is connected with power amplifier, and detection coil is connected with lock-in amplifier, data acquisition device and lock-in amplifier phase
Even, sinusoidal signal excitation is applied to excitation coil by signal generator, power amplifier, then is acquired and is detected with lock-in amplifier
The voltage signal of coil；
Step 2: test specimen being processed into the plate test coupon that length is greater than thickness first, and the plate test coupon processed is fixed
On scan table；Four probes of dc-bit method are equidistantly fixed on the central axes of plate test coupon, and ensure probe and probe
The distance between be greater than plate test coupon width and thickness；Then apply constant electricity to No. 1 probe and No. 4 probes with constant-current source
It flows, while recording the variation of voltage between No. 2 probes and No. 3 probes with nanovoltmeter；Finally n group data are acquired with data acquisition device
And the conductivity for obtaining plate test coupon is calculated with formula (1-1)；
In formula: σ is the conductivity of plate test coupon, and ρ is the resistivity of plate test coupon, and I is the electric current of constant-current source output, and S is No. 2 spies
The distance between needle and No. 3 probes, UiThe voltage between No. 2 probes and No. 3 probes acquired for data acquisition device i-th,
W, H is respectively the width and thickness of plate test coupon, and n is the data group number of acquisition, and i indicates that Current data acquisition device acquires data
Group number number；
Step 3: placing the excitation coil and detection coil of detection method of eddy first above plate test coupon, and utilize signal
Device generates the sinusoidal excitation signal of predeterminated frequency, amplifies the sinusoidal excitation signal by power amplifier and is applied to excitation line
Circle；Then line is detected by the voltage signal of the amplified detection coil of lock-in amplifier locking phase with data acquisition device acquisition
Shown in the calculation formula such as formula (1-2) of the voltage signal V of circle,
J in formulaeFor the vortex density in plate test coupon, EsFor the electric field strength of ource electric current field, respectively by formula (1-3) and formula (1-4)
It is calculated；IpFor the electric current for flowing through detection coil, cond. indicates area of space locating for detection coil；
Je=-j ω σ Ar (1-3)
ω is the angular frequency of sinusoidal excitation signal in formula, and σ is the conductivity of plate test coupon, ArIt is vector magnetic relevant to vortex field
Position；
Wherein σ is the conductivity of plate test coupon, and μ is the magnetic conductivity of plate test coupon, AsIt is related to the exciting current in excitation coil
Vector magnetic potential；
Step 4: in step 3 by eddy current testing device measure detection coil voltage signal V and plate test coupon conductivityσ and
Magnetic permeability μ is related, and the conductivityσ of plate test coupon can be measured by the dc-bit method in step 2, then the magnetic conductivity of plate test coupon
μ is obtained by the voltage signal V to detection coil using conjugate gradient method inverting.
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