CN102721735A - Metal surface/sub-surface magnetic-acoustic imaging probe applying Lorentz force - Google Patents
Metal surface/sub-surface magnetic-acoustic imaging probe applying Lorentz force Download PDFInfo
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- CN102721735A CN102721735A CN2012102435757A CN201210243575A CN102721735A CN 102721735 A CN102721735 A CN 102721735A CN 2012102435757 A CN2012102435757 A CN 2012102435757A CN 201210243575 A CN201210243575 A CN 201210243575A CN 102721735 A CN102721735 A CN 102721735A
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Abstract
The invention provides a metal surface/sub-surface magnetic-acoustic imaging probe applying Lorentz force, relating to magneto-acoustic imaging methods. The metal surface/sub-surface magnetic-acoustic imaging probe is provided with a connecting device, a probe shell, shielded conductors, a bias magnetic field, transmitting coils, receiving coils and a protection layer, wherein the connecting device is fixed on the probe shell; the shielded conductors are respectively connected among the connecting device, the transmitting coils and the receiving coils; the bias magnetic field is fixed above the transmitting coils and the receiving coils; and the protection layer is adhered below the transmitting coils and the receiving coils.
Description
Technical field
The present invention relates to a kind of magnetosonic formation method, is exactly a kind of magnetosonic imaging probe that is used for metal surface/surface, Asia specifically.
Background technology
All there is the depression problem inevitably in sheet metal in manufacturing process, in transportation, more can there be the damage that is produced by stress and reason such as collide with in processing and use in the maintenance process.For sheet material; The damage on its surface and inferior surface thereof has very strong disguise and dangerous, and the people's the security of the lives and property and the ecologic environment that we depend on for existence in serious threats such as the traffic hazard that causes thus, industrial accident and pipeline leakage accident.
At present; In the Non-Destructive Testing field; Using is exactly the piezoelectric supersonic detection method with proven technique the most extensively, and it is according to the defective of ultrasonic reflection principle detection sheet metal, and promptly ultrasound wave runs into crackle and can reflect when the sheet material internal communication; Through analyzing reflected ultrasonic wave, can confirm the position and the size of crackle.But, for ultrasound wave is incided in the sheet material, need between piezoelectric ultrasonic transducer and plate surface, add couplant (generally making water or glycerine), this brings a lot of difficulties for the application of piezoelectric supersonic detection method.
Owing to do not need couplant, and need not carry out pre-service to detected surface, rise in last century six the seventies the electromagnetic acoustic detection technique become the focus of Recent study gradually.But the limitation of electromagnetic acoustic detection technique is that the detected surface defect information amount that can extract is very few, is difficult to defective locations to plate surface and positions and estimate its degree of impairment.
Summary of the invention
The objective of the invention is to the less problem of existing electromagnetic acoustic detection technique information extraction amount, a kind of magnetosonic imaging probe of using the metal surface/surface, Asia of Lorentz force is provided.
The present invention is provided with coupling arrangement, probing shell, shielded conductor, bias magnetic field, transmitting coil, receiving coil and protective seam; Said coupling arrangement is fixed on the probing shell; Shielded conductor is connected on respectively between coupling arrangement and transmitting coil, the receiving coil; Bias magnetic field is fixed on transmitting coil and receiving coil top; Protective seam is attached to transmitting coil and receiving coil below.
Said bias magnetic field can adopt permanent magnet or electromagnet.
Said bias magnetic field provides a magnetic field for the detected material surface, so that charged particle can produce Lorentz force under this magnetic field.The peripheral magnetic field that this magnetic field is included as that transmitting coil provides the central magnetic field of bias magnetic field and bias magnetic field is provided for receiving coil.Because the polarity in central magnetic field and peripheral magnetic field can be identical, also can be opposite, according to actual conditions, under the central magnetic field prerequisite identical, can these two magnetic fields be united two into one with peripheral polarity of the magnetic field.
Below, said transmitting coil centering magnetic field.Through using a row high-frequency pulse current stimulated emission coil, make the detected object surface form instantaneous inductive loop.Inductive loop produces Lorentz force under the effect of bias magnetic field.The charged particle of detected material surface receives the periodically effect of Lorentz force, forms surface acoustic wave.Electrical impedance and the acoustic impedance information that surface acoustic wave is carrying this position to around propagate.
Said receiving coil places below, peripheral magnetic field, is the center with the transmitting coil, along its placed around, receives the surface acoustic wave that is produced by detected object.Disturb for reducing, the space between receiving coil and the transmitting coil is unsuitable excessive, thus to the sensing range of object to be detected only limit to transmitting coil under.
The signal of popping one's head in and being extracted among the present invention can adopt the backprojection reconstruction technology to carry out image reconstruction.The ultimate principle of backprojection reconstruction technology is:
Utilize the detected material surface to take up an official post to anticipate the charged particle of position, make the time spent characteristics of vibration in one direction only receiving Lorentz force f; At a plurality of receiving coils of transmitting coil peripheral disposition, receiving from a plurality of directions, the surface acoustic wave that inspires by transmitting coil.
Probe is sent into the electric signal that receives after the signal processing system; At first pass through the Lorentz force divergence distribution
of method acquisition time reversal detected material surface; Utilizing the diffusing property of nothing and the current density of current density again is that zero this boundary condition reconstructs transient current density on the normal orientation component, and then obtains the conductivity map picture of detected material surface.
Description of drawings
Fig. 1 is the general structure synoptic diagram of the embodiment of the invention.
Fig. 2 is the loop construction synoptic diagram of PCB coil in the embodiment of the invention 1.
Fig. 3 is the loop construction synoptic diagram of PCB coil in the embodiment of the invention 2.
Fig. 4 is the loop construction synoptic diagram on PCB coil upper strata in the embodiment of the invention 2.
Fig. 5 is the loop construction synoptic diagram of PCB coil lower floor in the embodiment of the invention 2.
Fig. 6 is the synoptic diagram of bias magnetic field in the embodiment of the invention 1.
Fig. 7 is the synoptic diagram of bias magnetic field in the embodiment of the invention 2.
Embodiment
Below in conjunction with accompanying drawing the present invention is described further.
Embodiment 1: referring to Fig. 1, Fig. 2, Fig. 6, the present invention is a kind of magnetosonic imaging probe.It is made up of coupling arrangement 1, probing shell 2, shielded conductor 3, bias magnetic field 4, transmitting coil 5, receiving coil 6, protective seam 7, and coupling arrangement 1 is fixed on the probing shell 2; Shielded conductor 3 is connected on respectively between coupling arrangement 1 and transmitting coil 5, the receiving coil 6; Bias magnetic field 4 is located at transmitting coil 5, receiving coil 6 tops; Protective seam 7 is posted in transmitting coil 5, receiving coil 6 belows.
Said bias magnetic field 4 is provided by a circular permanent magnet 41 and an annular permanent magnet 42, and its structure is as shown in Figure 6.Circular permanent magnet 41 is placed in the annular permanent magnet 42, and the two is concentric.Circular permanent magnet 41 is used to provide central magnetic field, and annular permanent magnet 42 is used to provide peripheral magnetic field.Transmitting coil and receiving coil are printed by a thick double-deck pcb board of 0.5mm and formed, and be as shown in Figure 2.Transmitting coil is the inflection double-spiral structure, and receiving coil is focusing inflection structure.
The quantity N of receiving coil is directly related with the angle of image resolution δ of probe.When evenly placing N receiving coil around the transmitting coil, under the situation of not considering distance between receiving coil, the angle of image resolution δ of probe can be similar to the satisfied δ=360 °/N that concerns.On the other hand, under the certain situation of bending number of times, the quantity of receiving coil is many more, and the surface acoustic wave intensity that then can receive is more little.In the present embodiment, take all factors into consideration angle of image resolution and receive two factors of signal intensity, receiving coil quantity N is set at 8.
From obtaining the angle of ceiling capacity conversion efficiency, require the spacing l between two strands of transmitting coil and receiving coil to satisfy phase relation matching condition: l=C/2f.The C speed that to be surface acoustic wave propagate in detected surface wherein, f is used for the frequency of high-frequency impulse of stimulated emission coil.In the present embodiment, selecting the high-frequency impulse frequency is 500Khz, and object to be detected is aluminum products, and the velocity of propagation of surface acoustic wave under this medium is about 5000m/s.Therefore can get through calculating, the distance between two strands of transmitting coil and receiving coil is about 5mm.
The lift-off value D of detected material surface of popping one's head in is relevant with above-described coil-span l.Specifically, for suppressing the adverse effect that Lift-off effect brings, the lift-off value D of the detected material surface of popping one's head in should be much smaller than coil-span l exactly.According to practical experience, the relation between lift-off value D and the coil-span l should satisfy: D＜l/2.Therefore, in the present embodiment, the lift-off value of the detected material surface of popping one's head in is made as 1mm.
Embodiment 2: combine Fig. 1, Fig. 3, Fig. 4, Fig. 5, Fig. 7, the present invention is a kind of magnetosonic imaging probe.It is made up of coupling arrangement 1, probing shell 2, shielded conductor 3, bias magnetic field 4, transmitting coil 5, receiving coil 6, protective seam 7; Coupling arrangement 1 is fixed on the probing shell 2; Shielded conductor 3 is connected on respectively between coupling arrangement 1 and transmitting coil 5, the receiving coil 6; Bias magnetic field 4 is fixed on transmitting coil 5, receiving coil 6 tops; Protective seam 7 is posted in transmitting coil 5, receiving coil 6 belows.
Bias magnetic field 4 is provided by a square permanent magnet and four rectangle permanent magnets, and its structure is as shown in Figure 7.The square permanent magnet places the center to be used to provide central magnetic field, is used to provide peripheral magnetic field around four rectangle permanent magnets place respectively, and five permanent magnets structure that is centrosymmetric is placed.Transmitting coil and receiving coil are printed by a thick double-deck pcb board of 0.5mm and formed, and be as shown in Figure 3.The transmitting coil of pcb board the upper and lower is insulated from each other, and angle is 90 °, and receiving coil is divided into two-layer up and down equally, is the broken line structure, prints according to the mode of Figure 4 and 5.
The quantity N of receiving coil is directly related with the imaging X axle resolution δ of probe.When evenly placing N receiving coil around the transmitting coil, under the situation of not considering distance between receiving coil, the angle of image resolution δ of probe can be similar to the satisfied δ=360 °/N that concerns.On the other hand, under the certain situation of bending number of times, the quantity of receiving coil is many more, and the surface acoustic wave intensity that then can receive is more little.In the present embodiment, take all factors into consideration angle of image resolution and receive two factors of signal intensity, receiving coil quantity N is set at 8.
Spacing l between transmitting coil and receiving coil two strands is identical with embodiment 1 with the assignment procedure of the lift-off value D of the detected material surface of popping one's head in, repeats no more at this.
The above be merely the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto.Any technician who is familiar with the present technique field is in the technical scope that the present invention discloses, and the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.
Claims (2)
1. a magnetosonic imaging probe of using the metal surface/surface, Asia of Lorentz force is characterized in that being provided with coupling arrangement, probing shell, shielded conductor, bias magnetic field, transmitting coil, receiving coil and protective seam; Said coupling arrangement is fixed on the probing shell; Shielded conductor is connected on respectively between coupling arrangement and transmitting coil, the receiving coil; Bias magnetic field is fixed on transmitting coil and receiving coil top; Protective seam is attached to transmitting coil and receiving coil below.
2. a kind of magnetosonic imaging probe of using the metal surface/surface, Asia of Lorentz force as claimed in claim 1 is characterized in that said bias magnetic field adopts permanent magnet or electromagnet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN2012102435757A CN102721735A (en) | 2012-07-13 | 2012-07-13 | Metal surface/sub-surface magnetic-acoustic imaging probe applying Lorentz force |
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| CN2012102435757A CN102721735A (en) | 2012-07-13 | 2012-07-13 | Metal surface/sub-surface magnetic-acoustic imaging probe applying Lorentz force |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103217481A (en) * | 2013-04-02 | 2013-07-24 | 厦门大学 | Magnetoacoustic tomography-with-magnetic-induction probe applying magnetostriction |
| CN103353478A (en) * | 2013-06-28 | 2013-10-16 | 厦门大学 | Magnetoacoustic tomography and magnetic leakage tomography compounded non-destructive detection method |
| CN104007170A (en) * | 2014-05-19 | 2014-08-27 | 中国科学院大学 | Measuring method for molten metal purity degree through state conversion based on electromagnetic principle |
| CN109425376A (en) * | 2017-09-01 | 2019-03-05 | 中国特种设备检测研究院 | Electromagnetic ultrasonic transducer |
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| JPS59173749A (en) * | 1983-03-23 | 1984-10-01 | Mitsubishi Electric Corp | Plate wave transmitter and receiver |
| CN1051086A (en) * | 1990-11-21 | 1991-05-01 | 冶金工业部钢铁研究总院 | Automatic defect detection technology using electromagnetic ultrasonic |
| CN101247758A (en) * | 2005-05-11 | 2008-08-20 | 明尼苏达大学评议会 | Methods and apparatus for imaging with magnetic induction |
| CN101713642A (en) * | 2009-11-12 | 2010-05-26 | 哈尔滨工业大学 | Electromagnetic ultrasonic probe |
-
2012
- 2012-07-13 CN CN2012102435757A patent/CN102721735A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59173749A (en) * | 1983-03-23 | 1984-10-01 | Mitsubishi Electric Corp | Plate wave transmitter and receiver |
| CN1051086A (en) * | 1990-11-21 | 1991-05-01 | 冶金工业部钢铁研究总院 | Automatic defect detection technology using electromagnetic ultrasonic |
| CN101247758A (en) * | 2005-05-11 | 2008-08-20 | 明尼苏达大学评议会 | Methods and apparatus for imaging with magnetic induction |
| CN101713642A (en) * | 2009-11-12 | 2010-05-26 | 哈尔滨工业大学 | Electromagnetic ultrasonic probe |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103217481A (en) * | 2013-04-02 | 2013-07-24 | 厦门大学 | Magnetoacoustic tomography-with-magnetic-induction probe applying magnetostriction |
| CN103353478A (en) * | 2013-06-28 | 2013-10-16 | 厦门大学 | Magnetoacoustic tomography and magnetic leakage tomography compounded non-destructive detection method |
| CN103353478B (en) * | 2013-06-28 | 2016-02-03 | 厦门大学 | The compound lossless detection method of a kind of magnetosonic imaging and leakage field imaging |
| CN104007170A (en) * | 2014-05-19 | 2014-08-27 | 中国科学院大学 | Measuring method for molten metal purity degree through state conversion based on electromagnetic principle |
| CN104007170B (en) * | 2014-05-19 | 2016-10-05 | 中国科学院大学 | The method measuring molten metal degree of purity by condition conversion based on electromagnetic principle |
| CN109425376A (en) * | 2017-09-01 | 2019-03-05 | 中国特种设备检测研究院 | Electromagnetic ultrasonic transducer |
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Application publication date: 20121010 |