CN205958518U - A piezoelectric transducer that is used for pipeline supersound guided wave to detect a flaw - Google Patents
A piezoelectric transducer that is used for pipeline supersound guided wave to detect a flaw Download PDFInfo
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- CN205958518U CN205958518U CN201620882696.XU CN201620882696U CN205958518U CN 205958518 U CN205958518 U CN 205958518U CN 201620882696 U CN201620882696 U CN 201620882696U CN 205958518 U CN205958518 U CN 205958518U
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Abstract
The utility model discloses a piezoelectric transducer that is used for pipeline supersound guided wave to detect a flaw. The utility model discloses a piezoelectric transducer adopts the upper surface of a n curved surface transducing board unit to bond uniformly at the lower surface of flexible basement, and the upper surface of each curved surface transducing board unit is the plane, and the lower surface is the curved surface, hugs closely the surface of being surveyed the pipeline as the working face, and a n parallelly connected curved surface transducing board unit encircles along surface a week of being surveyed the pipeline, surveyed the pipeline excitation and receiving single modal zeroth order and twist reverse guided wave T (0, 1), the utility model provides a piezoelectric transducer energy conversion efficiency is high, volume small -size is compact, can directly laminate on the pipeline surface, and the especially adapted pipeline health monitoring that is used for can predict the utility model discloses to promote the development based on the pipeline health monitoring of supersound guided wave effectively.
Description
Technical field
This utility model is related to intellectual material and structural health monitoring technology and in particular to a kind of be used for pipe ultrasonic guided wave
The piezoelectric transducer of flaw detection.
Background technology
Pipeline, as a kind of important means of transport, plays irreplaceable effect in fields such as oil, chemical industry.Cut-off
In the end of the year 2013, China builds natural gas line and exceedes 60,000 kilometers, and crude oil pipeline exceedes 2.6 ten thousand kilometers, and it is public that processed oil pipeline exceedes 20,000
In, pipeline has become the important infrastructure concerning the life-blood of the national economy.In recent years, due to burn into accidental injury, abrasion etc. because
Element, domestic and international pipe safety Frequent Accidents, cause huge Loss of Life and property.Therefore, pipeline integrity detects and comments
Valency has great importance.To have a detecting distance remote due to it for lossless detection method based on supersonic guide-wave, the features such as low cost,
Have become as the important technical of pipeline integrity detection.At present, also mainly gone out based on the pipeline inspection technology of supersonic guide-wave
In the laboratory research stage, the instrument and the system that can be used in actual industrial pipe detection are also few.One main reasons is that
Pipeline guided wave has multi-modal, the complex characteristics of high frequency dispersion.With external diameter as 100mm, as a example the aluminum pipe of wall thickness 3mm, arrive in 0kHz
In the range of 200kHz, a total guided wave modal axially propagated more than 50.Each frequency correspond to two with
On guided wave modal.If the guided wave of single mode cannot be motivated, identify the echo letter relevant with defect from numerous guided waves
Breath will be faced with the difficulty being difficult to overcome.On the other hand, except zeroth order reverses guided wave T (0,1) outward, all of pipeline guided wave all has
More serious Dispersion, that is, velocity of wave change with the change of frequency.Because guided wave is all to adopt window function mostly
The special waveform excitation of modulation, Dispersion makes pumping signal shape become with the increase of ripple propagation distance to distort, simultaneously
Guided wave amplitude is decayed rapidly, thus being difficult to distance detection.The guided wave therefore how encouraging single mode and non-frequency dispersion is
The most crucial problem of pipeline Guided waves.
Longitudinal mode guided wave L (0,2) is easy to excite due to it, and has less frequency dispersion in certain frequency range,
Thus be the most extensive, the also guided wave modal of relative maturity studied at present.But longitudinal wave guide mode has footpath due to it
To displacement, when pipeline either internally or externally has liquid, part guided wave energy can be leaked in liquid, thus having a strong impact on
Detecting distance.Compare longitudinal mode guided wave L (0,2), zeroth order is reversed guided wave T (0,1) and had obvious advantage.Zeroth order reverses guided wave
T (0,1) is the guided wave modal of uniquely non-frequency dispersion in pipeline.Simultaneously because zeroth order reverses guided wave T (0,1) only has tangential displacement, and
Liquid can not bear shearing, therefore guided wave energy will not be leaked in the liquid that pipeline is transported.Therefore zeroth order torsion guided wave T (0,
1) in pipeline integrity detection field, there is important application prospect.But the zeroth order torsion of single mode can be encouraged at present to lead
The transducer of ripple T (0,1) is also little, significantly limit the application in pipeline integrity detection of T (0,1) guided wave.At present
In succession it is suggested through there being two classes to reverse wave guide energy converter, and be successfully realized business application.One class is with South West USA academy
(Southwest Research Institute) is the electromagnet ultrasonic changer of the research and development of representative
(U.S.Pat.No.6429650B1).This transducer passes through to lead to alternating current, thus forming alternating magnetic field, alternating magnetic field in coil
Ferromagnetic material is caused to be deformed by magnetostrictive effect, thus forming guided wave in the duct.But electromagnet ultrasonic changer
Need to apply a stronger bias magnetic field, thus the volume of transducer is relatively large.Additionally, electromagnet ultrasonic changer energy turns
Change efficiency is low, thus needing stronger driving source to improve signal to noise ratio.Above-mentioned factor makes electromagnet ultrasonic changer be only used for
Non-Destructive Testing and be not suitable for monitoring structural health conditions.Another kind of be the research and development with Imperial College of Britain as representative dry coupling
Piezoelectric transducer (A.Demma, P.Cawly and M.Lowe, The reflection of the fundamental
torsional mode from cracks and notches in pipes,J.Acoust.Soc.Am.114(2),2003).
The units such as China National Offshore Oil Corporation have also been developed similar dry coupling piezoelectric transducer (ZL 201010605979.7).Dry coupling
Piezoelectric transducer passes through circumferentially thickness shear piezoelectric patches, thus realizing reversing excitation and the reception of guided wave.But thickness is cut
Hob electric transducer in the case of being not added with pressure, simple shear is tended in deformation, thus detrusion is difficult to effectively transmit
To on pipeline.Pressue device makes dry coupling piezoelectric transducer volume larger.On the other hand, thickness shear type piezoelectric transducer resonance
Frequency is higher, typically much higher than the driving frequency of guided wave, thus transducer cannot encourage to improve energy near resonant frequency
Conversion efficiency.Above-mentioned 2 points make dry coupling piezoelectric transducer also be only suitable for pipeline non-destructive testing and are not suitable for the health prison of pipeline
Survey.
Compared with pipeline non-destructive testing, pipeline health monitoring technique is capable of the safe condition of real-time prediction pipeline, can simultaneously
Enough save manpower and time cost, from but the currently both at home and abroad study hotspot of pipeline integrity detection field and trend.Therefore
It is suitable for the transducer of pipeline health monitoring in the urgent need to research and development.Li Faxin seminar of Peking University latest developments are cut in a kind of face
Cut new piezoelectric transducer (ZL 201620284659.9), this transducer can motivate the water of single mode in slab construction
Straight snips cuts guided wave modal (SH0), but improper be directly used in pipeline, this transducer dimensions is little and energy conversion efficiency is high, therefore suitable
Close structural health inspection.Due to the horizontal shear guided wave modal (SH0) in slab construction on waveform configuration with pipeline in zero
Rank is reversed guided wave modal (T (0,1)) and is similar to, and the torsion being therefore hopeful to develop on this basis suitable channel health monitoring is led
Wave piezoelectric transducer, and then promote the development of pipeline health monitoring.
Utility model content
For the current wave guide energy converter lacking and being suitable for pipeline health monitoring, the utility model proposes one kind can be in pipe
Encourage and receive the piezoelectric transducer that single mode zeroth order reverses guided wave T (0,1) in road, this transducer have lightweight, size little and
The high feature of energy conversion efficiency, suitable pipeline health monitoring.
Piezoelectric transducer for pipe ultrasonic guide wave flaw detection of the present utility model includes：N curved surface transducing Slab element and
One flexible substrates；Wherein, the upper surface of each curved surface transducing Slab element is plane, is bonded in the surface of flexible substrates, bent
The upper surface of face transducing Slab element be shaped as rectangle, four sides are perpendicular to upper surface；The lower surface of curved surface transducing Slab element
For curved surface, curved surface along the projection of thickness direction and upper surface congruence, the outer surface curvature one of the curvature of curved surface and tested pipeline
Cause, lower surface is as work surface；, using the piezoelectric after polarization, polarised direction is along the string of work surface for curved surface transducing Slab element
Length direction, has piezoelectric coefficient d 24；The two relative sides parallel with polarised direction are electrode surface；N curved surface transducing plate list
The upper surface of unit is equably bonded in the lower surface of flexible substrates, and the polarised direction orientation of n curved surface transducing Slab element is consistent；n
The electrode surface of the homonymy of individual curved surface transducing Slab element is respectively adopted a wire and is electrically connected an electrode column, thus bent by n
Face transducing Slab element is in parallel；The work surface of each curved surface transducing Slab element is close to the outer surface of tested pipeline, is evenly distributed on
N curved surface transducing Slab element of the lower surface of flexible substrates is uniformly distributed along the outer surface circumference of tested pipeline, and around edge
The outer surface one week of tested pipeline；It is respectively arranged at two ends with locking mechanism in flexible substrates, by locking mechanism by flexible base
The two ends at bottom are connected so that piezoelectric transducer forms the annular linking into an integrated entity the outer surface being fixed on tested pipeline, n
Natural number for >=2.
Piezoelectric transducer encourages the supersonic guide-wave of tested pipeline as brake, or receives tested pipeline as sensor
Supersonic guide-wave；As the pumping signal that during brake, signal generator sends after power amplifier amplification, connect to two
Electrode column, encourages n curved surface transducing Slab element simultaneously, produces inplane shear by the d24 pattern of inverse pressure point effect in work surface
Deformation, to tested pipeline imposed load, motivates supersonic guide-wave；During as sensor, the supersonic guide-wave of tested pipeline causes often
There is inplane shear deformation in the work surface of individual curved surface transducing Slab element, thus by the d24 pattern of direct piezoelectric effect in electrode surface
Form dielectric displacement, n curved surface transducing Slab element in parallel, by after signal averaging, is connected to preamplifier by two electrode columns
Amplify, signal processing analysis system is transferred to by data acquisition digital simulation A/D card.
The upper surface of curved surface transducing Slab element is rectangle, and the length of side along flexible substrates length direction is long side a, along soft
Property base widths direction the length of side be minor face b, the minimum thickness of curved surface transducing Slab element is the peak of work surface away from upper surface
Distance be h, meet
The length of flexible substrates is L, and width is W, and thickness is H, meets b≤W≤4b, 0.1h≤H≤4h.Flexible substrates
Length is equal to the outer perimeter of tested pipeline, and flexible substrates have certain elasticity, thus enabling to n song by locking mechanism
Face transducing Slab element is securely around the outer surface of tested pipeline.
The piezoelectric of curved surface transducing Slab element adopts the piezoelectric monocrystal of PZT pottery, ferroelectric ceramics or ferroelectric type；If adopting
With pottery, its residual polarization during polarization, should be made to reach maximum；According to the piezoelectric monocrystal of ferroelectric type, then when polarizing it is ensured that its
There is larger piezoelectric coefficient d 24.Flexible substrates adopt low elastic modulus, elastomeric material, such as rubber.
When piezoelectric transducer is used as brake excitation supersonic guide-wave, signal generator produces the excitation letter of window function modulation
Number, signal center frequency is f0, signal frequency width is [fmin,fmax], this frequency band is referred to as working band.For suppressing high order mode
Torsional wave, fmaxShould be less than the single order cut-off frequency that tested pipeline reverses guided wave；Product for rejection band scope inner curved waveguides
Raw, quantity n of curved surface transducing Slab element should be greater than tested pipeline [0, fmax] frequency band range interior bending guided wave modal appearance is
High circumference order.The velocity of wave of the torsional wave that piezoelectric transducer excites is cg, wavelength is λ=cg/f0.For making piezoelectric transducer have
Higher energy conversion efficiency, the minor face b of preferred curved surface transducing Slab element meets：0.25λ≤b≤0.6λ.Meet above-mentioned pass
The piezoelectric transducer of system, can be in the mid frequency f of working band0Place encourages the zeroth order of single mode to reverse guided wave T (0,1).
In the same manner, when piezoelectric transducer is used as sensor reception supersonic guide-wave, the mid frequency of receipt signal is f0, signal frequency
Rate width is [fmin,fmax], this frequency band is referred to as working band.For suppressing the torsional wave of high order mode, fmaxShould be less than tested pipeline
Reverse the single order cut-off frequency of guided wave；For the generation of rejection band scope inner curved waveguides, quantity n of curved surface transducing Slab element should be big
In tested pipeline [0, fmax] the interior highest circumference order bending guided wave modal appearance of frequency band range.Piezoelectric transducer receives
The velocity of wave of torsional wave is cg, wavelength is λ=cg/f0.For making piezoelectric transducer have higher energy conversion efficiency, preferably bent
The minor face b of face transducing Slab element meets：0.25λ≤b≤0.6λ.Meet the piezoelectric transducer of above-mentioned relation, can be in work frequency
The mid frequency f of band0The zeroth order that place receives single mode reverses guided wave T (0,1).
Piezoelectric transducer of the present utility model can be in the mid frequency f of working band0Place's filtering bending guided wave modal, and
Only receive and reverse guided wave.
Piezoelectric transducer of the present utility model only encourages the principle of torsion guided wave T (0,1) of single mode as brake
As follows：After excitation transducer is arranged on tested pipeline, n curved surface transducing Slab element is uniformly distributed along tested pipeline circumference；
When n curved surface transducing Slab element is encouraged by AC signal simultaneously, curved surface transducing Slab element is due to the d24 pattern of inverse piezoelectric effect
Produce inplane shear deformation in work surface, thus forming circumferentially equally distributed shear stress in tested pipeline；Due to song
The quantity of face transducing Slab element is more than the highest circumference order of bending wave in working frequency range interior conduit so that adjacent curved surface transducing
The gap of Slab element is less than the half-wavelength being encouraged torsion guided wave, and such that it is able to approximate thinking, that piezoelectric transducer is applied to is tested
Load on pipeline is axisymmetric loads circumferentially；Bending guided wave modal is non-axisymmetry mode, therefore axisymmetric loads are not
Bending guided wave modal can be excited；On the other hand, the main displacement of longitudinal axiss Guided along tested pipeline axially, does not have circumference
Displacement, only understands excitement of torsional guided wave hence along circumferential axisymmetric loads；The frequency of pumping signal is in the single order of torsional wave again
Below cut-off frequency, therefore zeroth order torsional wave T (0,1) of single mode can only be excited.In the same manner, piezoelectric transducer of the present utility model
The principle only detecting zeroth order torsional wave T (0,1) of single mode as sensor is as follows：Receipt signal is in working band, connects
Collect mail number for torsional wave when, when having torsional wave in tested pipeline, torsional wave only along tested pipeline circumference displacement component,
And be uniformly distributed along tested pipeline circumference, circumferentially displaced component causes in the work surface generation face of each curved surface transducing Slab element
Detrusion, thus form dielectric displacement by the d24 pattern of direct piezoelectric effect in electrode surface；When having bending wave in tested pipeline,
Although bending wave contains circumferentially displaced component, circumferentially distributed uneven along tested pipeline, therefore transducer only has small part
Piezoelectric patches can form dielectric displacement；Because between n curved surface transducing Slab element, circuit is in parallel, therefore the signal being detected is actually near
Approximately equal to n curved surface transducing Slab element signal is average, and the bending wave signal of therefore superposition will be very faint, thus realizing filtering
The function of bending wave.
Advantage of the present utility model：
This utility model provides one can be in tested pipeline excitation and the zeroth order torsion guided wave T receiving single mode
The piezoelectric transducer of (0,1), the utility model proposes piezoelectric transducer energy conversion efficiency is high, small volume compact dimensions, energy
Enough directly it is fitted in pipe surface, be highly suitable for pipeline health monitoring it is anticipated that this utility model will effectively promote base
Development in the pipeline health monitoring of supersonic guide-wave.
Brief description
Fig. 1 is the schematic diagram that piezoelectric transducer of the present utility model is close on tested pipeline, and wherein, (a) is three-dimensional knot
Structure schematic diagram, (b) is side view；
Fig. 2 is the schematic diagram of the curved surface transducing Slab element of piezoelectric transducer of the present utility model；
Fig. 3 is the expanded schematic diagram of piezoelectric transducer of the present utility model；
Fig. 4 is 3mm for wall thickness, and the group velocity dispersion of guided wave in the range of 0-250kHz for the aluminum pipe for 100mm for the external diameter is bent
Line；
Fig. 5 reverses the waveform configuration figure of guided wave T (0,1) for zeroth order；
Fig. 6 is the embodiment one of piezoelectric transducer of the present utility model is 3mm as brake in wall thickness, and external diameter is
The aluminum pipe mid frequency of 100mm is the experimental result that 150kHz signal encourages T (0,1)；
Fig. 7 is the experiment knot as sensor reception supersonic guide-wave for the embodiment two of piezoelectric transducer of the present utility model
Really, supersonic guide-wave adopts the piezoelectric transducer excitation of 12 curved surface transducing Slab element, and wherein (a) is only 12 curved surface transducing plates
The oscillogram that the piezoelectric transducer of unit receives as sensor, (b) is with 32 curved surface transducing plate lists of the present utility model
The oscillogram that the piezoelectric transducer of unit receives as sensor.
Specific embodiment
Below in conjunction with the accompanying drawings, by specific embodiment, this utility model is expanded on further.
As shown in figure 1, the piezoelectric transducer of the present embodiment includes：N curved surface transducing Slab element 15 and flexible substrates
12；The upper surface of n curved surface transducing Slab element 15 is equably bonded in the surface of flexible substrates 12；N curved surface transducing Slab element
The electrode surface of homonymy be respectively adopted a wire and be electrically connected an electrode column, thus n curved surface transducing plate list after parallel connection
Unit is respectively connecting to positive electricity pole 17 and negative electrode lives 19；Work surface is close to the outer surface of tested pipeline 10, n curved surface transducing plate
Unit is uniformly distributed along the outer surface circumference of tested pipeline 10, and around the outer surface one week along tested pipeline.
The number of curved surface transducing Slab element is n, and n is more than tested pipeline 10 [0, fmax] frequency band range interior bending guided wave mould
The highest circumference order that state occurs.The length of flexible substrates 12 is equal to the outer perimeter of tested pipeline 10.
As shown in Fig. 2 curved surface transducing Slab element 15 upper surface is plane, it is shaped as rectangle；Lower surface is curved surface, curved surface
Curvature is consistent with the outer surface curvature of tested pipeline 10.Lower surface is work surface, is close to the outer surface of pipeline 10 during work.Work
The projection making face along transducing plate 15 thickness direction is congruent to the upper surface of transducing plate 15, and that is, the chord length of work surface is equal to upper surface
Length of side a.The curved surface transducing Slab element 15 two relative sides parallel and vertical with upper surface with polarised direction are electrode surface.
Fig. 3 illustrates the expanded view of piezoelectric transducer of the present utility model.When transducer is pasted onto pipeline 10, due to base
Bottom 12 is flexible material, therefore can be launched into a strip.When piezoelectric transducer needs to be close to tested pipeline 10, flexible base
Bottom 12 is passed through locking mechanism 14 head and the tail and is connected, and flexible substrates have elasticity, so that piezoelectric transducer is enclosed within tested pipeline 10, such as scheme
Shown in 1.As seen from Figure 3, curved surface transducing Slab element is evenly distributed in flexible substrates 12 surface, and channel wire 18 is realized
The circuit in parallel of curved surface transducing Slab element.
Zeroth order torsional wave T (0,1) being encouraged for further illustrating transducer of the present utility model is examined in pipeline integrity
The advantage in survey field, it is 3mm that Fig. 4 gives wall thickness, and external diameter is that the aluminum pipe of 100mm axially passes along aluminum pipe in 250kHz 0
The group velocity dispersion graph of a relation of the supersonic guide-wave broadcast.Can see that the guided wave axially propagated in tested pipeline has three classes：
One class is that (0, m), m is the modulus (m=1,2,3) of guided wave to axisymmetric longitudinal wave guide mode L, and another kind of is to reverse
(0, m), also a class is that (N, m), N is the week of guided wave to nonaxisymmetrical bending guided wave modal F to axisymmetric torsion guided wave modal T
To order (N=1,2,3).Can see zeroth order reverse guided wave T (0,1) be uniquely non-frequency dispersion guided wave modal, that is, its
Velocity of wave does not change with the change of frequency.The non-Dispersion of T (0,1) can make pumping signal shape and the propagation of guided wave
Speed keeps constant in communication process, thus improve the distance of detection, reduces the difficulty of signal analysis.Other direction,
Fig. 5 gives the waveform configuration figure that zeroth order reverses guided wave T (0,1).Can see that T (0,1) only has circumferentially displaced UθComponent, due to
Liquid can not bear detrusion, and the energy therefore reversing guided wave T (0,1) will not be leaked in liquid, thereby may be ensured that
Detecting distance, this makes T (0,1) be highly suitable for detecting the pipeline of transport liquid.Further, Fig. 5 shows that zeroth order is reversed
The displacement component of guided wave T (0,1) is almost equally distributed along tested pipeline wall thickness, and this explanation T (0,1) ripple is to tested pipeline
Surface and internal defect have identical detectivity, thus ensure that defect detection is not subject to defect in the shadow of pipe wall position
Ring.
Embodiment one
The zeroth order encouraging single mode for further illustrating piezoelectric transducer of the present utility model reverses guided wave T's (0,1)
Effectiveness, devises one for being 3mm in wall thickness, and external diameter encourages zeroth order to reverse the piezoelectricity of guided wave T (0,1) for 100mm aluminum pipe
Transducer.Piezoelectric transducer design center frequency is 150kHz, using the sinusoidal signal conduct in five cycles of Hanning window modulation
Pumping signal, therefore the highest frequency in working band is 210kHz.As shown in Figure 4, in 0～210kHz, bend guided wave F (N, 1)
Highest circumference order be 31, therefore the number of curved surface transducing Slab element be 32.After curved surface transducing Slab element is using polarization
PZT-5H pottery, is shaped as square, the upper surface length of side is 6mm, and minimum thickness h is 1.9mm.Flexible substrates adopt rubber,
Length is 314mm, a width of 12mm, and thick is 2mm.In order to test conveniently, the quantity being simultaneously prepared for curved surface transducing Slab element is 12
Piezoelectric transducer.
Fig. 6 illustrates the piezoelectric transducer of 32 curved surface transducing Slab element with preparing gained as brake, uses center
Frequency is 150kHz, and amplitude is the voltage of 20V is 3mm in wall thickness, and external diameter is the experiment knot of excitation T (0,1) on 100mm aluminum pipe
Really.Signal using curved surface transducing Slab element quantity be 12 piezoelectric transducer receive, due to the number of curved surface transducing Slab element
Less than the highest circumference order of bending guided wave F (N, 1), therefore this transducer can receive torsional wave and can receive bending guided wave mould again
State.Fig. 6 shows that the piezoelectric transducer of 32 curved surface transducing Slab element prepared by this utility model has successfully motivated single mould
State, zeroth order torsional wave T (0,1) of high s/n ratio, do not have any other mode of flexural vibration guided wave to be excited.Excitation point and receiving point
Between interval 600mm, such that it is able to calculate zeroth order torsional wave T (0,1) that piezoelectric transducer of the present utility model is encouraged
Theoretical value 3099m/s for T (0,1) in 3050m/s, with aluminum pipe for the velocity of wave is closely.Can see that this utility model is encouraged
Zeroth order torsional wave T (0,1) waveform completely the same with excitation signal waveforms, there is no any frequency dispersion.
Embodiment two
In the present embodiment, using the piezoelectric transducer of 32 curved surface transducing Slab element of preparation in embodiment one as sensing
Device.
The piezoelectric transducer that it is 12 with transducing plate number that Fig. 7 (a) illustrates encourages and uses in 150kHz as brake and changes
Energy plate number is the ultrasonic guided wave signals of 12 piezoelectric transducer reception.Can see and reverse guided wave T (0,1) outward except zeroth order,
Bending guided wave modal is also had to be excited out.Fig. 7 (b) illustrates when 32 curved surface transducing Slab element with this utility model preparation
Piezoelectric transducer as sensor when, only zeroth order reverse guided wave T (0,1) be detected, bending guided wave modal be filtered
?.This shows that this utility model can serve as filtered sensor, can greatly reduce the complexity of receipt signal, has weight
The using value wanted.
It is finally noted that, the purpose publicizing and implementing example is that help further understands this utility model, but this
The technical staff in field is appreciated that：Without departing from this utility model and appended spirit and scope by the claims, various
Substitutions and modifications are all possible.Therefore, this utility model should not be limited to embodiment disclosure of that, and this utility model will
The scope asking protection is defined by the scope that claims define.
Claims (8)
1. a kind of piezoelectric transducer for pipe ultrasonic guide wave flaw detection is it is characterised in that described piezoelectric transducer includes：N
Curved surface transducing Slab element and flexible substrates；Wherein, the upper surface of each curved surface transducing Slab element is plane, is bonded in soft
The surface of property substrate, the upper surface of described curved surface transducing Slab element be shaped as rectangle, four sides are perpendicular to upper surface；Curved surface
The lower surface of transducing Slab element is curved surface, curved surface along the projection and upper surface congruence of thickness direction, the curvature of curved surface with tested
The outer surface curvature of pipeline is consistent, and lower surface is as work surface；Curved surface transducing Slab element is using the piezoelectric after polarization, polarization
Direction, along the chord length direction of work surface, has piezoelectric coefficient d 24；The two relative sides parallel with polarised direction are electrode
Face；The upper surface of n curved surface transducing Slab element is equably bonded in the lower surface of flexible substrates, n curved surface transducing Slab element
Polarised direction orientation is consistent；The electrode surface of the homonymy of n curved surface transducing Slab element is respectively adopted a wire and is electrically connected one
Electrode column, thus n curved surface transducing Slab element is in parallel；The work surface of each curved surface transducing Slab element is close to tested pipeline
Outer surface, n curved surface transducing Slab element being evenly distributed on the lower surface of flexible substrates is circumferential along the outer surface of tested pipeline
It is uniformly distributed, and around the outer surface one week along tested pipeline；It is respectively arranged at two ends with locking mechanism in flexible substrates, pass through
Locking mechanism the two ends of flexible substrates are connected so that piezoelectric transducer formed the annular that links into an integrated entity and be fixed on by
The outer surface in test tube road, n is >=2 natural number.
2. piezoelectric transducer as claimed in claim 1 is it is characterised in that the upper surface of described curved surface transducing Slab element is square
Shape, the length of side along flexible substrates length direction is long side a, and the length of side along flexible substrates width is minor face b, and curved surface changes
Can Slab element minimum thickness be the distance away from upper surface for the peak of work surface be h, meet
3. it is characterised in that the width of described flexible substrates is W, thickness is H to piezoelectric transducer as claimed in claim 2, full
Sufficient b≤W≤4b, 0.1h≤H≤4h.
4. piezoelectric transducer as claimed in claim 1 is it is characterised in that the length of described flexible substrates is equal to tested pipeline
Outer perimeter.
5. piezoelectric transducer as claimed in claim 1 is it is characterised in that the piezoelectric of described curved surface transducing Slab element adopts
The piezoelectric monocrystal of PZT pottery, ferroelectric ceramics or ferroelectric type.
6. piezoelectric transducer as claimed in claim 1 is it is characterised in that described flexible substrates adopt low elastic modulus.
7. piezoelectric transducer as claimed in claim 1 is it is characterised in that described piezoelectric transducer is ultrasonic as brake excitation
Guided wave, the mid frequency of the pumping signal that signal generator produces is f0, signal frequency width is [fmin,fmax], this frequency band claims
For working band；fmaxReverse the single order cut-off frequency of guided wave less than tested pipeline；Quantity n of described curved surface transducing Slab element is big
In tested pipeline [0, fmax] the interior highest circumference order bending guided wave modal appearance of frequency band range；Piezoelectric transducer excites
The velocity of wave of torsional wave is cg, wavelength is λ=cg/f0；The minor face b of described curved surface transducing Slab element meets：0.25λ≤b≤0.6λ.
8. piezoelectric transducer as claimed in claim 1 is it is characterised in that described piezoelectric transducer is ultrasonic as sensor reception
Guided wave, the mid frequency of receipt signal is f0, signal frequency width is [fmin,fmax], this frequency band is referred to as working band；fmaxLittle
Reverse the single order cut-off frequency of guided wave in tested pipeline；Quantity n of described curved surface transducing Slab element be more than tested pipeline [0,
fmax] the interior highest circumference order bending guided wave modal appearance of frequency band range；The velocity of wave of torsional wave that piezoelectric transducer receives is
cg, wavelength is λ=cg/f0；The minor face b of described curved surface transducing Slab element meets：0.25λ≤b≤0.6λ.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620882696.XU CN205958518U (en) | 2016-08-15 | 2016-08-15 | A piezoelectric transducer that is used for pipeline supersound guided wave to detect a flaw |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620882696.XU CN205958518U (en) | 2016-08-15 | 2016-08-15 | A piezoelectric transducer that is used for pipeline supersound guided wave to detect a flaw |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110346451A (en) * | 2019-08-20 | 2019-10-18 | 浙江省特种设备科学研究院 | A kind of supersonic guide-wave monitoring transducer |
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2016
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110346451A (en) * | 2019-08-20 | 2019-10-18 | 浙江省特种设备科学研究院 | A kind of supersonic guide-wave monitoring transducer |
| CN110346451B (en) * | 2019-08-20 | 2024-04-05 | 浙江省特种设备科学研究院 | Ultrasonic guided wave monitoring transducer |
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