CN107356681A - A kind of unidirectional detection method of magnetic striction wave guide - Google Patents
A kind of unidirectional detection method of magnetic striction wave guide Download PDFInfo
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- CN107356681A CN107356681A CN201710571667.0A CN201710571667A CN107356681A CN 107356681 A CN107356681 A CN 107356681A CN 201710571667 A CN201710571667 A CN 201710571667A CN 107356681 A CN107356681 A CN 107356681A
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- excitation
- sensor
- guided wave
- detection method
- magnetic striction
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/24—Probes
- G01N29/2412—Probes using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]
Abstract
The invention belongs to technical field of nondestructive testing, discloses a kind of unidirectional detection method of magnetic striction wave guide, including：(1) dispersion curve of tested component is obtained；(2) driving frequency and excitation number are set；(3) guide wavelength is determined；(4) initial phase of pumping signal is set as 0, first time guided wave excitation and Guided waves is carried out with the driving frequency of setting simultaneously, excitation number subtracts 1；(5) stimulus sensor is moved to a quarter guide wavelength in one direction, and the initial phase of pumping signal is changed into pi/2, carries out guided wave excitation and Guided waves simultaneously again, excitation number subtracts 1；(6) operation of repeat step (5), until detection number is 0；(7) by repeated detection to guided wave signals be overlapped.The present invention realizes the one direction excitation of the magnetic striction wave guide in component and received, at the same overcome guide wavelength it is smaller when the limitation that is brought to the size of stimulus sensor.
Description
Technical field
The present invention relates to technical field of nondestructive testing, more particularly to a kind of unidirectional detection method of magnetic striction wave guide.
Background technology
Decay during magnetostrictive ultrasonic guided waves propagation small, can be realized by single-point-excitation to long-distance pipe or shaft-like
The large-scale detection of framework；Supersonic guide-wave sound field in pipeline or rod component throughout whole cross section, can detect simultaneously
Surface and internal flaw.Due to above-mentioned advantage, the detection technique is widely used in industrial quarters.
When existing portion of techniques is detected using magnetostrictive effect, the guided wave motivated in component is all two-way
Propagate, echo-signal of the same defect to the guided wave of both direction can be received by receiving sensor, can not so judge to lack
Sunken position and quantity, mutually superimposed interference can be produced even from the signal at both ends, can not correctly judge whether defect.
Various limitations be present in the method that existing part carries out Non-Destructive Testing using magnetostriction, such as：(1) two are used
Highest guided wave frequency is restricted workable for the prior art of stimulus sensor, because as the wavelength of guided wave is with frequency
The increase of rate and reduce, when being encouraged using upper frequency, the centre distance of two stimulus sensors is shorter.The width of cell winding
Degree is the minimum value of two stimulus sensor centre distance when being detected, and is reduced to meet spacing quarter-wave
Coil width and the intensity of the guided wave motivated will be reduced when reducing coil turn, or even guided wave can not be motivated.(2) two are used
The prior art of individual stimulus sensor and two reception sensors usually requires that two stimulus sensor coils and its pumping signals
Channel gain is identical, and the gain of two reception cell windings and its signal input channel is identical.(3) two are used
The method that the prior art of sensor usually not proposes accurately two hub of a spool spacing of control, and spacing is accurately that energy is real
The key of existing guided wave one direction Detection results.(4) prior art usually requires rule of thumb to set some parameters.(5) existing skill
Some steps need to be participated in manually in the sequence of operations that art uses, such as two to receiving signal division ripple bags.
The content of the invention
The embodiment of the present invention solves two-way in the prior art by providing a kind of magnetic striction wave guide unidirectional detection method
Echo ripple bag correspondence position is unique during propagation, the superposition of two-way signaling causes the increase of detection signal analysis difficulty, workable
The problem of driving frequency is limited by size sensor.
The embodiment of the present invention provides a kind of unidirectional detection method of magnetic striction wave guide, comprises the following steps：
(1) dispersion curve of tested component is obtained；
(2) driving frequency and excitation number are set according to the dispersion curve；
(3) guide wavelength is determined according to the driving frequency；
(4) initial phase of pumping signal is set as 0, is carried out for the first time with the driving frequency by single stimulus sensor
Guided wave encourages, while carries out first time Guided waves by single reception sensor, and the excitation number subtracts 1；
(5) stimulus sensor is moved into guide wavelength described in a quarter in one direction, and the excitation is believed
Number initial phase change pi/2, carry out guided wave excitation and Guided waves simultaneously again, the excitation number subtracts 1；
(6) operation of repeat step (5), until the detection number is 0；
(7) by it is described reception sensor repeated detection to guided wave signals be overlapped.
Preferably, the excitation number is 2 times or 4 times.
Preferably, the guided wave excitation uses the sinusoidal signal of windowed function.
Preferably, the window function is one kind in rectangular window, Hanning window, hamming window, Gaussian window.
Preferably, the movement of the stimulus sensor is realized by stepper motor drive ball-screw motion.
The one or more technical schemes provided in the embodiment of the present invention, have at least the following technical effects or advantages：
In embodiments of the present invention, using a stimulus sensor and a reception sensor, stimulus sensor is several times
Guided wave is motivated, the position movement a quarter guide wavelength of stimulus sensor, the initial phase of pumping signal when homogeneous does not encourage
Change pi/2；Detection and record that sensor carries out guided wave signals are received while excitation, sensor is repeatedly received during excitation
Position keeps constant；By the superposition of repeated detection signal, the waveguide propagated in one direction can be eliminated, while strengthen along another
The waveguide that individual direction is propagated.The present invention is based on Signal averaging principle, realizes the one direction of magnetic striction wave guide in component and swashs
Encourage and receive；Guided wave is encouraged respectively in the position of spacing a quarter guide wavelength using single stimulus sensor, is overcome and is led
The limitation brought when ripple wavelength is smaller to the size of stimulus sensor.
Brief description of the drawings
It is required in being described below to embodiment to use in order to illustrate more clearly of the technical scheme in the present embodiment
Accompanying drawing is briefly described, it should be apparent that, drawings in the following description are one embodiment of the present of invention, for this area
For those of ordinary skill, on the premise of not paying creative work, other accompanying drawings can also be obtained according to these accompanying drawings.
Fig. 1 is a kind of flow chart of the unidirectional detection method of magnetic striction wave guide provided in an embodiment of the present invention；
Fig. 2 is the framework of the detecting system in a kind of unidirectional detection method of magnetic striction wave guide provided in an embodiment of the present invention
Figure；
Fig. 3 is the excitation signal waveforms in a kind of unidirectional detection method of magnetic striction wave guide provided in an embodiment of the present invention
Figure；
Fig. 4 is the stimulus sensor positioning in a kind of unidirectional detection method of magnetic striction wave guide provided in an embodiment of the present invention
The left view of device；
Fig. 5 is the stimulus sensor positioning in a kind of unidirectional detection method of magnetic striction wave guide provided in an embodiment of the present invention
The top view of device；
Fig. 6 is a kind of schematic diagram for the unidirectional detection method of magnetic striction wave guide that the embodiment of the present invention 1 provides；
Fig. 7 is a kind of schematic diagram for the unidirectional detection method of magnetic striction wave guide that the embodiment of the present invention 2 provides；
Fig. 8 is a kind of schematic diagram for the unidirectional detection method of magnetic striction wave guide that the embodiment of the present invention 3 provides.
Wherein, 1- stepper motors, 2- slide units, 3- ball-screws, 4- guide rails, 5- stimulus sensors support, 6- excitation sensings
Device, 7- receive sensor, 8- components to be measured.
Embodiment
The embodiment of the present invention solves two-way in the prior art by providing a kind of magnetic striction wave guide unidirectional detection method
Echo ripple bag correspondence position is unique during propagation, the superposition of two-way signaling causes the increase of detection signal analysis difficulty, workable
The problem of driving frequency is limited by size sensor.
The technical scheme of the embodiment of the present invention is in order to solve the above technical problems, general thought is as follows：
A kind of unidirectional detection method of magnetic striction wave guide, comprises the following steps：
(1) dispersion curve of tested component is obtained；
(2) driving frequency and excitation number are set according to the dispersion curve；
(3) guide wavelength is determined according to the driving frequency；
(4) initial phase of pumping signal is set as 0, is carried out for the first time with the driving frequency by single stimulus sensor
Guided wave encourages, while carries out first time Guided waves by single reception sensor, and the excitation number subtracts 1；
(5) stimulus sensor is moved into guide wavelength described in a quarter in one direction, and the excitation is believed
Number initial phase change pi/2, carry out guided wave excitation and Guided waves simultaneously again, the excitation number subtracts 1；
(6) operation of repeat step (5), until the detection number is 0；
(7) by it is described reception sensor repeated detection to guided wave signals be overlapped.
The present invention motivates guided wave several times using a stimulus sensor and a reception sensor, stimulus sensor,
The position movement a quarter guide wavelength of stimulus sensor, the initial phase of pumping signal change pi/2 when homogeneous does not encourage；Swashing
Detection and record that sensor carries out guided wave signals are received while encouraging, the position that sensor is repeatedly received during excitation is kept not
Become；By the superposition of repeated detection signal, the waveguide propagated in one direction can be eliminated, while strengthen and propagated along another direction
Waveguide.The present invention is based on Signal averaging principle, realizes the one direction excitation of the magnetic striction wave guide in component and receives；Profit
Encourage guided wave respectively in the position of spacing a quarter guide wavelength with single stimulus sensor, overcome guide wavelength it is smaller when
The limitation brought to the size of stimulus sensor.
In order to be better understood from above-mentioned technical proposal, below in conjunction with Figure of description and specific embodiment to upper
Technical scheme is stated to be described in detail.
A kind of unidirectional detection method of magnetic striction wave guide is present embodiments provided, is comprised the following steps：
(1) dispersion curve of tested component is obtained；
(2) driving frequency and excitation number are set according to the dispersion curve；
(3) guide wavelength is determined according to the driving frequency；
(4) initial phase of pumping signal is set as 0, is carried out for the first time with the driving frequency by single stimulus sensor
Guided wave encourages, while carries out first time Guided waves by single reception sensor, and the excitation number subtracts 1；
(5) stimulus sensor is moved into guide wavelength described in a quarter in one direction, and the excitation is believed
Number initial phase change pi/2, carry out guided wave excitation and Guided waves simultaneously again, the excitation number subtracts 1；
(6) operation of repeat step (5), until the detection number is 0；
(7) by it is described reception sensor repeated detection to guided wave signals be overlapped.
Therefore, user only needs to select the frequency of pumping signal, required excitation number, window function according to dispersion curve
Type and length, stimulus sensor position control software, which automatic will calculate velocity of wave, wavelength, stimulus sensor, need to move every time
Distance, and control pumping signal that software, data processing software and stimulus sensor positioner occurs according to the stream shown in Fig. 1
Journey completes whole detection process.
The frame diagram of the detecting system of the present invention is as shown in Figure 2.Wherein, system software include dispersion curve software for calculation,
Software, data processing software occur for stimulus sensor position control software, pumping signal.System hardware includes magnetic striction wave guide
Detector, sensor (magnetizing coil, excitation coil, receiving coil), thread spool positioner.Magnetostriction guided wave detector is by believing
Number power amplification circuit, impedance matching circuit, signal condition and adc circuit composition.Thread spool positioner mainly includes stepping electricity
Drive circuit, stepper motor, ball-screw.
The present invention encourages guided wave using a stimulus sensor, and guided wave is received using a reception sensor.Will during detection
Pumping signal input stimulus sensor, the guided wave propagated to both direction is motivated in component to be measured, in the same of excitation triggering
When using receive sensor detection guided wave signals.Then stimulus sensor is moved into λ/4 (λ is guide wavelength), pumping signal frequency
Rate keeps constant, input stimulus sensor after phase change pi/2, encourages guided wave again and is led simultaneously using reception sensor
Ripple detects.A kind of simplest situation, is encouraged twice altogether, by the way that the guided wave signals detected when encouraging twice are folded
Add, you can realize that the guided wave amplitude propagated in one direction doubles, the guided wave amplitude cancellation propagated along another direction, carry simultaneously
High signal to noise ratio.A kind of preferable situation, stimulus sensor is moved to four diverse locations at a distance of λ/4, using phase according to
The secondary pumping signal for changing pi/2 carries out four guided wave excitations, then will receive four guided wave signals detected of sensor and carries out
Superposition, this scheme can further improve the amplitude for the guided wave propagated in one direction, so as to further improve signal to noise ratio.
Wherein, exciting signal frequency is identical with target guided wave frequency, and phase difference is the sinusoidal signal of pi/2, and passes through window letter
Number makes its duration be 3~10 cycles, and selectable window function includes rectangular window, Hanning window, hamming window, Gaussian window
(alpha=1).Fig. 3 is the excitation waveform after the windowed function by taking 5 cycles as an example, and left side is 0 degree of initial phase, and right side is first
90 degree of phase.
Stimulus sensor positioner shown in Fig. 4 and Fig. 5 include stepper motor 1, slide unit 2, ball-screw 3, guide rail 4,
Stimulus sensor support 5, stimulus sensor 6.The accurate fixed of stimulus sensor is realized by the stimulus sensor positioner
Position, excitation coil is arranged on the slide unit 2 of the ball-screw 3, the ball wire is driven using the stepper motor 1
Thick stick 3 moves.
Fig. 6, Fig. 7, Fig. 8 are respectively embodiment 1, embodiment 2, the schematic diagram of embodiment 3, are filled except stimulus sensor positions
Putting also includes receiving sensor 7, component to be measured 8.
User obtains the parameter of component to be measured first, then calculates dispersion curve using dispersion curve software for calculation.User
Driving frequency, excitation number are selected according to dispersion curve.The frequency that stimulus sensor position control software is inputted according to user from
It is dynamic to calculate velocity of wave, wavelength and set the distance that needs are mobile every time.Stimulus sensor position control software occurs to pumping signal
Software assigns pumping signal parameter.Magnetostriction guided wave detector completes excitation signal waveforms generation, power amplification output, echo
The detection of signal, conditioning, ADC, and send data processing software to be handled.Data processing software notifies after receiving echo-signal
The detection process of this excitation of stimulus sensor position control software is completed.Stimulus sensor position control software driving stepping electricity
Machine simultaneously drives ball-screw to move, and excitation coil is moved quarter-wave, while requires that software adjustment occurs for pumping signal
90 degree of the initial phase of pumping signal next time, then start to encourage next time.Said process is repeated, until defined excitation number
Complete.
Embodiment 1 as shown in fig. 6, using encouraging twice, and the initial phase of first time pumping signal is 0 degree, second of excitation
When stimulus sensor be moved to the left quarter-wave, pumping signal initial phase is 90 degree.The guided wave signals detected twice are folded
After adding, the guided wave amplitude motivated to the right is offset, and the guided wave amplitude motivated to the left doubles.
Embodiment 2 as shown in fig. 7, using encouraging twice, and the initial phase of first time pumping signal is 0 degree, second of excitation
When stimulus sensor be moved to the left quarter-wave, pumping signal initial phase is minus 90 degree.The guided wave signals detected twice
After superposition, the guided wave amplitude motivated to the left is offset, and the guided wave amplitude motivated to the right doubles.
Embodiment 3 as shown in figure 8, using four excitations, the initial phase of each secondary pumping signal be followed successively by 0 degree, it is minus 90 degree, bear
180 degree and minus 270 degree, stimulus sensor is moved to the left quarter-wave after excitation every time.Four guided wave signals detected
After superposition, the guided wave amplitude motivated to the left is offset, and the guided wave amplitude motivated to the right is changed into original about four times.
By four excitations, change a quarter guide wavelength, phase place change per stimulus sensor position when encouraging twice
90 ° (or minus 90 °), receive sensor and carry out four Guided waves and record, and the signal that four times are detected in same position
It is overlapped, further enhances signal to noise ratio.
In addition, effect of the user according to detection, stimulus sensor position control software can be calculated needs to move every time
Dynamic distance is finely adjusted, and the guided wave signals for being re-started the multiple excitation of guided wave by the displacement after fine setting and being detected
Superposition.
The unidirectional detection method of a kind of magnetic striction wave guide provided in an embodiment of the present invention comprises at least following technique effect：
In embodiments of the present invention, using a stimulus sensor and a reception sensor, stimulus sensor is several times
Guided wave is motivated, the position movement a quarter guide wavelength of stimulus sensor, the initial phase of pumping signal when homogeneous does not encourage
Change pi/2；Detection and record that sensor carries out guided wave signals are received while excitation, sensor is repeatedly received during excitation
Position keeps constant；By the superposition of repeated detection signal, the waveguide propagated in one direction can be eliminated, while strengthen along another
The waveguide that individual direction is propagated.The present invention is based on Signal averaging principle, realizes the one direction of magnetic striction wave guide in component and swashs
Encourage and receive；Guided wave is encouraged respectively in the position of spacing a quarter guide wavelength using single stimulus sensor, is overcome and is led
The limitation brought when ripple wavelength is smaller to the size of stimulus sensor.
It should be noted last that above embodiment is merely illustrative of the technical solution of the present invention and unrestricted,
Although the present invention is described in detail with reference to example, it will be understood by those within the art that, can be to the present invention
Technical scheme modify or equivalent substitution, without departing from the spirit and scope of technical solution of the present invention, it all should cover
Among scope of the presently claimed invention.
Claims (5)
1. a kind of unidirectional detection method of magnetic striction wave guide, it is characterised in that comprise the following steps：
(1) dispersion curve of tested component is obtained；
(2) driving frequency and excitation number are set according to the dispersion curve；
(3) guide wavelength is determined according to the driving frequency；
(4) initial phase of pumping signal is set as 0, and first time guided wave is carried out with the driving frequency by single stimulus sensor
Excitation, while first time Guided waves are carried out by single reception sensor, the excitation number subtracts 1；
(5) stimulus sensor is moved into guide wavelength described in a quarter in one direction, and by the pumping signal
Initial phase changes pi/2, carries out guided wave excitation and Guided waves simultaneously again, and the excitation number subtracts 1；
(6) operation of repeat step (5), until the detection number is 0；
(7) by it is described reception sensor repeated detection to guided wave signals be overlapped.
2. the unidirectional detection method of magnetic striction wave guide according to claim 1, it is characterised in that the excitation number is 2
It is secondary or 4 times.
3. the unidirectional detection method of magnetic striction wave guide according to claim 1 or 2, it is characterised in that the guided wave excitation
Using the sinusoidal signal of windowed function.
4. the unidirectional detection method of magnetic striction wave guide according to claim 3, it is characterised in that the window function is rectangle
One kind in window, Hanning window, hamming window, Gaussian window.
5. the unidirectional detection method of magnetic striction wave guide according to claim 1 or 2, it is characterised in that pass through stepper motor
Ball-screw motion is driven to realize the movement of the stimulus sensor.
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| CN104990984A (en) * | 2015-07-27 | 2015-10-21 | 华中科技大学 | Device and method for improving magnetostrictive guided wave detection sensitivity |
| KR101656368B1 (en) * | 2015-11-05 | 2016-09-09 | 영남대학교 산학협력단 | Method and apparatus for improving the transmitting and receiving directivity in long-range ultrasonic testing |
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| CN1139758A (en) * | 1995-06-09 | 1997-01-08 | 三菱电机株式会社 | Non-destruction detector |
| CN101710103A (en) * | 2009-11-27 | 2010-05-19 | 华中科技大学 | Unidirectional testing method of magnetostrictive guided waves |
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