CN109725061A - The method of evaluating characteristics epoxy resin mortar laminate structure performance is dissipated using R wave frequency - Google Patents
The method of evaluating characteristics epoxy resin mortar laminate structure performance is dissipated using R wave frequency Download PDFInfo
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Abstract
The present invention relates to Hydraulic structure Material technical field of nondestructive testing, especially a kind of method that evaluating characteristics epoxy resin mortar laminate structure performance is dissipated using R wave frequency determines exciting hammer, two receiving sensor spacing and the exciting hammer and sensor spacing of suitable size；At the impacting point of design with hammering generate elastic wave, on the measuring point of design lay acceleration transducer receive respectively different moments by epoxy resin mortar thin layer be propagated through come R wave signal；By the analysis and processing to twice or the received R wave time-domain signal of multiple tracks sensor, the phase difference spectrum and R wave velocity of wave of signal are sought respectively, and establish phase frequency spectrum and dispersion curve；Analytical derivation R wave parameter judges the formula of epoxy resin mortar thin layer performance, the feasibility judged with phase frequency spectrum and dispersion curve；It is handled by the analysis to R wave signal at different measuring points, judges the performance of epoxy resin mortar thin layer.The present invention provides a kind of effective means for efficient quick obtaining epoxy resin mortar thin layer performance parameter.
Description
Technical field
The present invention relates to Hydraulic structure Material technical field of nondestructive testing, especially a kind of to dissipate evaluating characteristics epoxy using R wave frequency
The method of mortar thin layer structural behaviour.
Background technique
Hydraulic concrete buildings are under the multiple actions such as water impact or low temperature freeze-thaw damage, it may appear that surface damage,
The decay and aging for easily causing concrete material, seriously affect the safe operation of hydraulic concrete buildings.To ensure water conservancy project
The operational safety of building often need to carry out surface layer protection to built and newly-built concrete surface.Epoxy resin mortar be by epoxy resin,
The other materials such as curing agent and sand are formulated by a certain percentage, have intensity high, modulus is low, ultimate elongation is big, bonding is strong
The characteristics such as degree is high, gain in strength is fast, are one of main hydraulic concrete buildings surface layer protective materials.International Commission on Large Dams
Once 100, the survey whole world carries out the dam of upstream face repairing using resinous material, wherein 73% using epoxy
Resin or the material based on epoxy resin.Since epoxy resin mortar thin layer protective materials is exposed to outdoor open-air atmosphere more, for a long time
Influenced by the complex conditions such as stress, damp and hot, inevitably will appear material property degradation phenomena, it is therefore necessary to its into
The assessment of row on-site test, determines its performance and situation of change.
Common layer material quality determining method is mainly pull-out test both at home and abroad at present, although this method is simply straight
It sees, but since this method is damaged method, is unfavorable for large-scale use, there are certain application limitations, and are only capable of being drawn
Intensity is pulled out, there is an urgent need to carry out the detection of epoxy resin mortar material property by lossless detection method thus.
Summary of the invention
In view of the above technical problems, evaluating characteristics epoxy resin mortar laminate structure is dissipated using R wave frequency the present invention provides a kind of
The method of performance, efficient quick obtaining epoxy resin mortar thin layer performance parameter.
The technical solution adopted by the present invention is that:
The method of evaluating characteristics epoxy resin mortar laminate structure performance, including following procedure are dissipated using R wave frequency:
(1) the exciting hammer, receiving sensor spacing, exciting hammer and sensing of suitable size are determined according to the feature of research object
Device distance；Elastic wave is generated with hammering at the impacting point of design, acceleration transducer is laid on the measuring point of design and is connect respectively
Receive different moments by epoxy resin mortar thin layer be propagated through come R wave signal；
(2) by the analysis and processing to twice or the received R wave time-domain signal of multiple tracks sensor, signal is sought respectively
Phase difference spectrum and R wave velocity of wave, and establish phase frequency spectrum and dispersion curve；
(3) analytical derivation R wave parameter judges the formula of epoxy resin mortar thin layer performance, is carried out with phase frequency spectrum and dispersion curve
The feasibility of judgement；
(4) it is handled by the analysis to R wave signal at different measuring points, judges the performance of epoxy resin mortar thin layer.
Specific detailed process are as follows:
(1) R wave in-situ check and test method and data acquire
By two acceleration transducers as the surface of detected object, with hammering at the impacting point of sensor side design
Generate elastic wave, received respectively by sensor different moments by epoxy resin mortar thin layer be propagated through come vibration signal.According to
The feature of research object determines the exciting hammer of suitable size, two receiving sensor spacing, exciting hammer and sensor distance.Due to ring
Oxygen mortar thin layer structural thickness is smaller, between general 1-5cm, it is necessary to which the material of laminate structure could be detected by obtaining high-frequency signal
Performance.
(2) R wave velocity of wave and phase spectrum are sought
Pass through the cross-correlation function r to twice or the received R wave time-domain signal of multiple tracks sensor21(t) Fourier's change is carried out
It changes, sees below formula (1), to obtain cross-correlation function r21(t) phase differenceWith the relationship of frequency f, i.e. phase difference spectrum, i.e. formula
(1) in
F in formula21(ω) is cross-correlation function r21(t) Fourier transformation indicates two channel signals v1(t) and v2(t)
Cross-power frequency spectrum function；F1(ω) and F2(ω) respectively indicates two channel signals v1(t) and v2(t) Fourier transformation；F1*(ω)
Indicate F1The complex conjugate of (ω)；|F21(ω) | it is cross-correlation function r21The amplitude frequency spectrum of (τ),It is cross-correlation function r21(τ)
Phase frequency spectrum, i.e. two sensors x1、x2Phase difference at two o'clock, two sensors spacing d.
The received discrete time signal of two road sensors is analyzed, so that the phase information of R wave crosspower spectrum is obtained,
That is phase frequency spectrum.
Propagation time difference is calculated by following formula:
Δ t is R wave propagation time difference between two sensors, unit s in formula；T indicates R wave period, unit s；F indicates R wave
Frequency, unit Hz；
According to R wave propagation time difference Δ t under different frequency f, the velocity of wave V of R wave under different frequency can be calculatedR:
There are following relationships between R wave velocity, wavelength and frequency:
VR=λRf (4)
In formula: VR is R wave velocity, m/s；λ R is R wave wavelength, m；F is R wave frequency rate, Hz.
The surface wave velocity of wave V of frequency f can be obtained accordinglyRAnd obtain dispersion curve VR~λR。
(3) epoxy resin mortar layer material performance evaluation
Dynamic modulus of elasticity is the stress and strain ratio of the material under dynamic loading, usually reflects material with the parameter
Performance.But due to being limited and many factors such as experimental data discreteness by material strain rate sensitivity, testing equipment
It influences, obtains the test method of dynamic modulus of elasticity to not yet forming a set of at present in the way of dynamically load, and use substantially
Elastic wave testing method.
Impact elasticity wave method is to calculate its dynamic modulus of elasticity by measuring elastic wave (P wave, the R wave) speed of material.But
Due to epoxy resin mortar thin layer, only one can survey free face, do not have longitudinal wave (P wave) to the condition of survey, can only use surface wave (R
Wave) it is detected.
Can be assumed that concrete and epoxy resin mortar are perfect elastic body under the conditions of small strain, the speed of elastic wave (P wave) and
Dynamic modulus of elasticity has following relationship:
One-dimensional propagation (in rod piece):
Three-dimensional propagates (infinite space):
In formula: VP1And VP3One peacekeeping three-dimensional spread speed of P wave is respectively represented, μ is dynamical possion ratio, and ρ is density of material.
According to the wave equation of elastic wave, using the condition that face power is zero at medium free boundary, P wave, S wave in medium
With R wave velocity VP3、VSAnd VRMeet formula 6.
Formula 6 is auspicious Lei Fangcheng, wherein VRIt is the solution that the equation meets specified conditions.Due to VP3And VSRatio only
It is related with the dynamical possion ratio μ of dielectric material, and meet formula 7.
Formula 6 can be converted into one and include surface velocity of wave VRAnd constant VSWith μ equation, meet condition 8.
According to above formula, when the dynamical possion ratio μ of dielectric material is between 0.15~0.30, VP3、VSAnd VRNumerical relation is such as
Under:
μ=0.15:VS=1.11VR, VP3=1.73VR
μ=0.20:VS=1.10VR, VP3=1.79VR (9)
μ=0.30:VS=1.08VR, VP3=2.01VR
By analysis above it is found that in practical applications, if using the Dispersion of R wave, by dispersion curve come
Epoxy resin mortar surface is measured with the lower V along depth boundsRDistribution, so that it may the variation of dynamic modulus of elasticity Ed is estimated, to slap
Hold the superiority and inferiority and latent defect of epoxy resin mortar internal soundness.
(4) graph is drawn, judges the performance of epoxy resin mortar layer material
Using frequency as abscissa (arithmetic coordinate), using phase difference as ordinate, the phase difference at different measuring points is drawn respectively
Spectral curve；Again using R wave wavelength as abscissa, with R wave velocity of wave ordinate, the R wave dispersion curve at different measuring points is drawn respectively.It is comprehensive
The feature of both curves at analysis different measuring points position is closed, therefore, it is determined that the internal soundness of epoxy resin mortar thin layer and bonding are imitated
Fruit.
Compared with prior art, the beneficial effects of the present invention are:
The present invention proposes a kind of method that evaluating characteristics epoxy resin mortar laminate structure performance is dissipated using R wave frequency, by not
With the analysis processing of R wave signal at measuring point, so that it may judge the performance of epoxy resin mortar thin layer, be efficient quick obtaining epoxy resin mortar
Thin layer performance parameter provides a kind of effective means.
Detailed description of the invention
Fig. 1 is embodiment R wave method detection arrangement；
Fig. 2 a is the typical R wave time-domain signal that embodiment two sensors receive that 17mm diameter exciting hammer taps generation；
Fig. 2 b is the typical R wave time-domain signal that embodiment two sensors receive that 30-50mm diameter exciting hammer taps generation；
Fig. 3 is embodiment R wave velocity of wave and phase spectrum calculation flow chart；
Fig. 4 a is that embodiment #12-1 measuring point sensor spacing 20cm, 17mm exciting hammers phase spectrum into shape；
Fig. 4 b is that embodiment #12-1 measuring point sensor spacing 50cm, 30-50mm exciting hammers phase spectrum into shape；
Fig. 4 c is embodiment #12-1 measuring point R wave dispersion curve；
Fig. 5 a is that embodiment #14-2 measuring point sensor spacing 20cm, 17mm exciting hammers phase spectrum into shape；
Fig. 5 b is that embodiment #14-2 measuring point sensor spacing 50cm, 30-50mm exciting hammers phase spectrum into shape；
Fig. 5 c is embodiment #14-2 measuring point R wave dispersion curve；
Fig. 6 a is that embodiment #16-2 measuring point sensor spacing 20cm, 17mm exciting hammers phase spectrum into shape；
Fig. 6 b is that embodiment #16-2 measuring point sensor spacing 50cm, 30-50mm exciting hammers phase spectrum into shape；
Fig. 6 c is embodiment #16-2 measuring point R wave dispersion curve；
Fig. 7 is embodiment #16-2 measuring point core sample actual state.
Specific embodiment
The invention will be further described With reference to embodiment.
By taking certain workshop spillwag chute large area epoxy resin mortar material non-destructive testing research work as an example, illustrate the application of this patent
Method and effect.
1) field engineering arrangement and initial data obtain
Specific work arrangement is as shown in Figure 1, acceleration transducer is adsorbed in by magnetic support pastes in advance in overfall dam table
The gasket in face.The spacing of acceleration transducer is respectively set to 20cm and 50cm, and when spacing 20cm is hammered into shape using diameter 17mm exciting
Exciting is carried out, high frequency R wave component is obtained, to detect surface layer epoxy resin mortar quality.Meanwhile also having chosen spacing 50cm, diameter
50mm and 30mm two kinds of excitings hammer carry out excitings, are mainly bonded effect and concrete detect epoxy resin mortar thin layer and concrete
Internal soundness.
Detection parameters sample frequency is 25kHz (4 μ s of sampling interval), sampling number 1024.Since epoxy resin mortar is heat
Sensitive material, epoxy resin mortar modulus declines after temperature increases, and spectral interference probability increases, therefore the detection of epoxy resin mortar thin layer should use up
Amount avoids the high temperature period, and guarantees that object to be measured temperature is held essentially constant.Different size exciting hammers tap lower twice sensing
The typical temporal signal that device receives is shown in Fig. 2 a and Fig. 2 b.
2) epoxy resin mortar laminate structure performance evaluation
In practical applications, the received discrete time signal of two road sensors is analyzed using the algorithm pattern of Fig. 3, from
And obtain the phase information of R wave crosspower spectrum, i.e. phase frequency spectrum.
According to field condition, 11 measuring points have been laid altogether at the top of #12~#16 monolith spillway workshop.According to above
Data processing step carries out analysis and arrangement, the Phase Difference Spectrum and R wave dispersion curve of 3 test result different measuring points of final choice into
Row explanation:
As shown in Fig. 4 a, Fig. 4 b, Fig. 4 c, tri- kinds of hammers of 17mm, 30mm and 50mm are respectively adopted and carry out exciting, phase spectrum is opposite
Compare clear, three kinds of dispersion curves are almost the same, show inner concrete uniform quality, surface wave velocity of wave VR2500~
2600m/s；V at wavelength 8cmRAbout 1760m/s.Epoxy resin mortar thin layer and concrete quality are preferable.
As shown in Fig. 5 a, Fig. 5 b, Fig. 5 c, tri- kinds of hammers of 17mm, 30mm and 50mm are respectively adopted and carry out exciting, phase spectrum is opposite
Compare it is clear, but 17mm exciting hammer dispersion curve and 30~50mm exciting hammer into shape dispersion curve it is larger in longer wavelength dimensional discrepancy,
Show to connect not close, surface wave velocity of wave V between epoxy resin mortar thin layer and base concreteRNear 2500m/s, but epoxy sand
Starch surface layer VRAbout 1000m/s.Epoxy resin mortar thin layer velocity of wave is lower in general, and epoxy resin mortar is second-rate.
As shown in Fig. 6 a, Fig. 6 b, Fig. 6 c, tri- kinds of hammers of 17mm, 30mm and 50mm are respectively adopted and carry out exciting, wherein 17mm is hammered into shape
Test phase spectrum has severe jamming, and low frequency region phase spectrum does not show apparent regularity, epoxy resin mortar and interfacial adhesion
Quality may be poor.The R scattering of wave curve graph of 30-50mm hammer shows inner concrete uniform quality, surface wave velocity of wave VR?
Near 2500m/s.
In order to verify the accuracy of testing result, the practical core boring sampling observation epoxy resin mortar and interior near #16-2 measuring point
The quality of portion's concrete, is shown in Fig. 7.It can be found that epoxy resin mortar color is deeper, compactness is poor, there are pore and micro-crack, with
Test result is consistent substantially.
Claims (4)
1. dissipating the method for evaluating characteristics epoxy resin mortar laminate structure performance using R wave frequency, which is characterized in that including following procedure:
(1) according to the feature of research object determine suitable size exciting hammer, receiving sensor spacing, exciting hammer and sensor away from
From；Elastic wave is generated with hammering at the impacting point of design, acceleration transducer is laid on the measuring point of design and is received respectively not
In the same time by epoxy resin mortar thin layer be propagated through come R wave signal；
(2) by the analysis and processing to twice or the received R wave time-domain signal of multiple tracks sensor, the phase of signal is sought respectively
Difference frequency spectrum and R wave velocity of wave, and establish phase frequency spectrum and dispersion curve；
(3) analytical derivation R wave parameter judges the formula of epoxy resin mortar thin layer performance, is clearly carried out with phase frequency spectrum and dispersion curve
The feasibility of judgement；
(4) it is handled by the analysis to R wave signal at different measuring points, judges the performance of epoxy resin mortar thin layer.
2. the method according to claim 1 for dissipating evaluating characteristics epoxy resin mortar laminate structure performance using R wave frequency, feature
It is, the step (2) includes following procedure:
Pass through the cross-correlation function r to twice or the received R wave time-domain signal of multiple tracks sensor21(t) Fourier transformation is carried out, is seen below
Formula (1), to obtain cross-correlation function r21(t) phase differenceWith the relationship of frequency f, i.e. phase difference spectrum, i.e., in formula (1)
F in formula21(ω) is cross-correlation function r21(t) Fourier transformation indicates two channel signals v1(t) and v2(t) mutual function
Rate frequency spectrum function；F1(ω) and F2(ω) respectively indicates two channel signals v1(t) and v2(t) Fourier transformation；F1 *(ω) is indicated
F1The complex conjugate of (ω)；|F21(ω) | it is cross-correlation function r21The amplitude frequency spectrum of (τ),It is the phase of cross-correlation function r21 (τ)
Position frequency spectrum, i.e. two sensors x1、x2Phase difference at two o'clock, two sensors spacing d；
The received discrete time signal of two road sensors is analyzed, to obtain the phase information of R wave crosspower spectrum, i.e. phase
Position frequency spectrum:
Propagation time difference is calculated by following formula:
Δ t is R wave propagation time difference between two sensors, unit s in formula；T indicates R wave period, unit s；F indicates R wave frequency rate,
Unit Hz；
According to R wave propagation time difference Δ t under different frequency f, the velocity of wave V of R wave under different frequency can be calculatedR:
There are following relationships between R wave velocity, wavelength and frequency:
VR=λRf (4)
In formula: VR is R wave velocity, m/s；λ R is R wave wavelength, m；F is R wave frequency rate, Hz.
The surface wave velocity of wave V of frequency f can be obtained accordinglyRAnd obtain dispersion curve VR~λR。
3. the method according to claim 1 for dissipating evaluating characteristics epoxy resin mortar laminate structure performance using R wave frequency, feature
It is, the step (3) includes following procedure: using the surface wave i.e. Dispersion of R wave, ring is measured by dispersion curve
Oxygen mortar surface is with lower along depth bounds inner surface velocity of wave VRDistribution, estimate dynamic modulus of elasticity Ed variation, to grasp ring
The superiority and inferiority and latent defect of oxygen mortar internal soundness.
4. the method according to claim 1 for dissipating evaluating characteristics epoxy resin mortar laminate structure performance using R wave frequency, feature
It is, the step (4) includes following procedure:
Using frequency as abscissa, using phase difference as ordinate, the Phase Difference Spectrum curve at different measuring points is drawn respectively；Again with R wave
Wavelength is abscissa, with R wave velocity of wave ordinate, draws the R wave dispersion curve at different measuring points respectively；Comprehensive analysis different measuring points
The feature of both curves at position, therefore, it is determined that the internal soundness and bonding effect of epoxy resin mortar thin layer.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110346454A (en) * | 2019-07-24 | 2019-10-18 | 四川幔壳科技有限公司 | Concrete superficial layer ultrasound surface wave detection method based on arranged type ultrasonic vibration source |
| CN110455916A (en) * | 2019-08-20 | 2019-11-15 | 深圳大学 | A kind of solid material recognition methods based on acoustics dispersion phenomenon |
-
2019
- 2019-01-26 CN CN201910076264.8A patent/CN109725061A/en active Pending
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| Title |
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| 吕小彬等: "基于卓越波长的瞬态表面波法的应用", 《水利水电技术》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110346454A (en) * | 2019-07-24 | 2019-10-18 | 四川幔壳科技有限公司 | Concrete superficial layer ultrasound surface wave detection method based on arranged type ultrasonic vibration source |
| CN110455916A (en) * | 2019-08-20 | 2019-11-15 | 深圳大学 | A kind of solid material recognition methods based on acoustics dispersion phenomenon |
| CN110455916B (en) * | 2019-08-20 | 2022-04-08 | 深圳大学 | Solid material identification method based on acoustic dispersion phenomenon |
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Application publication date: 20190507 |