CN104913988B - Concrete axial tensile strength measuring method based on Hopkinson principle - Google Patents
Concrete axial tensile strength measuring method based on Hopkinson principle Download PDFInfo
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- CN104913988B CN104913988B CN201510237759.6A CN201510237759A CN104913988B CN 104913988 B CN104913988 B CN 104913988B CN 201510237759 A CN201510237759 A CN 201510237759A CN 104913988 B CN104913988 B CN 104913988B
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Abstract
The invention discloses a kind of concrete axial tensile strength measuring method based on Hopkinson principle, and concrete sample is carried out using Hopkinson pressure bar device（10）Axial tensile strength measurement, it is characterised in that：Remove the transmission bar in described Hopkinson pressure bar device；In the test specimen（10）Array foil gauge is provided with impingement distance end（50）；In described concrete axial test specimen（10）Free end（11）One accelerometer is set（30）；Pass through described accelerometer（30）The analysis of oscillogram monitored draws described test specimen free end（11）Acceleration；Described test specimen free end is calculated（11）The speed on surface；Measure described test specimen free end（11）Speed, then measure described concrete sample by calculating analysis（10）The tensile strength in axle center.The present invention can accurately measure the tensile strength for calculating concrete axle center under the conditions of middle high strain-rate.
Description
Technical field
The present invention relates to the measuring method of concrete axial tensile strength, more particularly to a kind of coagulation based on Hopkinson principle
Native axial tensile strength measuring method.
Background technology
Concrete material is most common construction material, is widely applied in various industries.In blast, impact etc.
, it is necessary to know the axial tensile strength of concrete exactly to determine that concrete can bear accidental in the presence of high speed load
Load.At present, in terms of concrete axial tensile strength is measured, the method for domestic and international generally use is mainly hydraulic servo experiment
System, but be only limitted under conditions of in general low strain dynamic rate, for the concrete axle center under conditions of higher strain rate
The measurement of tensile strength is also highly difficult, is primarily due to mean that amplitude is wanted in the pulse of incidence wave under the conditions of higher strain rate
It is low, length is lasted, but the length of incident bar is inadequate, so as to cause incidence wave to be difficult to handle with back wave overlapped signal.Another
The concrete axial tensile strength measuring method generally used is strain gauge method.This method is directly viscous on concrete sample
Foil gauge is pasted, by the maximum for the elongation strain being recorded directly on foil gauge, on the premise of the hypothesis of material, with stretching
Tensile strength of the product of maximum and modulus of elasticity as material is strained, still, with the increase of fracture position distance, reflection
Tension is obviously reduced, and the tension of concrete material can not be being represented away from the transmitting tension crest value that fracture position measures
Intensity, therefore, the defects of this measuring method it is：Low strain dynamic rate condition is only applicable to, and middle high strain-rate bar can not be applied to
Concrete axial tensile strength measurement under part.
The content of the invention
A kind of the defects of it is an object of the invention to overcome prior art, there is provided concrete axial based on Hopkinson principle
Heart tensile strength measuring method, can be accurately measured under the conditions of middle high strain-rate calculate concrete axle center tension it is strong
Degree.
In order to solve the above-mentioned technical problem, the present invention uses following technical scheme：
A kind of concrete axial tensile strength measuring method based on Hopkinson principle, using Hopkinson pressure bar device
The axial tensile strength measurement of concrete sample is carried out, including concrete sample, incident bar, bullet, foil gauge, its feature exist
In：Remove the transmission bar in described Hopkinson pressure bar device；Number is provided with the concrete sample impingement distance end
Group foil gauge；In the described free end for stating concrete sample, one accelerometer is set；Supervised by described accelerometer
The Acceleration pulse map analysis measured draws the acceleration of described concrete sample free end；Described concrete is calculated
The speed of test specimen free end surface；The speed of described concrete sample free end is measured, is then measured by calculating analysis
The tensile strength in described concrete sample axle center.
Measuring method of the present invention specifically includes following steps：
(1) one accelerometer is set in described concrete sample free end, and passes through a bridge box and a data
Acquisition Instrument is connected；
(2) vertical plane of described incident bar butt end is bonded with the perpendicular end surface at the shock end of described concrete sample
Together；
(3) with the end of the projectile impact incident bar, biography is measured by the array foil gauge set on concrete sample
To the strain waveform figure in the concrete sample, and the accelerometer described in measures the acceleration of concrete sample free end
Oscillogram；
(4) by the array foil gauge measured by strain waveform figure, according to formulaCalculate wave velocity C0, its
In, L is the length of concrete sample, Δ t refer to incidence wave enter concrete sample to concrete sample free end spent when
Between；
Then according to formulaThe dynamic elastic modulus E of concrete is calculated, wherein E refers to the dynamic of concrete
Modulus of elasticity, ρ refer to the density of concrete sample；
According to formulaThe dependent variable ε of the concrete sample is asked for, wherein Δ L represents concrete examination
The elongation of part, Δ u are represented at the time of concrete sample starts to occur tensile stress to speed in the time interval of fracture
Variable quantity, it is that the pattern fits collected by the accelerometer of free end are drawn；
According further to formula σ=E ε, stress is extrapolated
(5) according to formulaCalculate strain rate, wherein tpRepresent that concrete sample starts to occur stretching to answer
To the time interval of fracture at the time of power；Wherein, σ refers to stress, and E refers to the dynamic modulus of elasticity, tpRepresent that concrete sample is opened
To the time interval of fracture at the time of beginning tensile stress occur；
(6) size that the bullet injects air pressure is adjusted, above-mentioned (3)-(5) step is repeated, asks for respectively in difference
Air pressure conditions are the strain rate under the conditions of different strain rate, finally draw the axial tensile strength of described concrete axial test specimen-
Strain rate relation curve.
Preferably, 3 groups of foil gauges are provided with the concrete sample impingement distance end, are separately positioned on the concrete
At test specimen impingement distance end 100mm, 200mm, 300mm.
Wherein, the foil gauge in described every group is serially connected, and then every group of foil gauge and described bridge box is corresponding defeated
It is serial connected respectively to enter end, then bridge box is serially connected with data collecting instrument.
Preferably, the size of described concrete sample is diameter 74mm, length 500mm.
Preferably, the length of the bullet is 100mm.
Compared with prior art, the present invention has advantages below and beneficial effect：
1. the scope that the present invention is applicable is wide, low strain dynamic rate condition is may be not only suitable for, be particularly suitable for use in middle high strain-rate
Under the conditions of concrete axial tensile strength measurement.
2. measurement result precision is high；Tensile strength is easily determined when test specimen is repeatedly broken；Maximum tensile stress and actual feelings
Condition meets.
3. experimental result can not only obtain spallation strength, moreover it is possible to obtain the relevant information such as damage development in spallation process.
Brief description of the drawings
Fig. 1 is the measurement installation diagram of measurement apparatus incident bar of the invention, test specimen and accelerometer.
Fig. 2 is the Acceleration pulse schematic diagram that the accelerometer of the present invention is collected.
Fig. 3 is the waveform diagram of the speed obtained by the Acceleration pulse according to Fig. 2.
Fig. 4 is the graph of relation of stress-time of the present invention.
Fig. 5 is concrete axial test specimen axial tensile strength-strain rate graph of relation of the present invention.
Wherein, 10 concrete axial test specimen, 11 test specimen free ends, 20 incident bars, 30 accelerometers, 40 bullets, 50 foil gauges,
60 bridge boxes, 70 data collecting instruments.
Embodiment
The present invention is described in further details with specific embodiment below in conjunction with the accompanying drawings.
Concrete axial tensile strength measuring method of the invention based on Hopkinson principle, is filled using Hopkinson pressure bar
The axial tensile strength measurement for carrying out concrete sample 10 is put, as shown in figure 1, including concrete sample 10, incident bar 20, bullet
40th, foil gauge 50, it is characterised in that：Remove the transmission bar in described Hopkinson pressure bar device；In the concrete sample
Array foil gauge 50 is provided with 10 impingement distance ends；In the free end 11 of described concrete sample 10, an acceleration is set
Meter 30；The Acceleration pulse map analysis monitored by described accelerometer 30 draws adding for described test specimen free end 11
Speed；The speed on the described surface of test specimen free end 11 is calculated；The speed of described test specimen free end 11 is measured, then
The tensile strength in the described axle center of concrete sample 10 is measured by calculating analysis.
Measuring method of the present invention comprises the following steps：
(1) accelerometer 30 is set in described test specimen free end 11, and passes through a bridge box 60 and a data
Acquisition Instrument 70 is connected；In practical operation, it is stained with concrete sample free end 11 30 after accelerometer, is first connected with bridge box 60,
It is connected again with data collecting instrument 70.
(2) by the vertical plane of the described butt end of incident bar 20 and the perpendicular end surface at the shock end of described concrete sample 10
Fit together；
(3) end of incident bar 20 is hit with the bullet 40, is measured by the array foil gauge 50 set on test specimen 10
The strain waveform figure passed in the test specimen 10, and the accelerometer 30 described in use measures the Acceleration pulse of test specimen free end 11
Figure, Fig. 2 are the Acceleration pulse schematic diagrames that the accelerometer of the present invention is collected.
As shown in figure 3, it is the Acceleration pulse schematic diagram obtained by the Acceleration pulse according to Fig. 2：Pass through formula
It can obtain speed v：Wherein α represents acceleration, and t represents the time, and described Fig. 3 curves pass through soft according to the formula
Part is fitted to obtain.
(4) by the array foil gauge 50 measured by figure -- the graph of relation of stress-time shown in Fig. 4,
Again
According to formulaCalculate wave velocity C0, wherein, L is the length of test specimen, and Δ t refers to that incidence wave arrives into test specimen
The time spent in test specimen free end；
Then according to formulaThe dynamic elastic modulus E of concrete is calculated, wherein E refers to the dynamic of concrete
Modulus of elasticity, ρ refer to the density of concrete sample；
According to formulaThe dependent variable ε of the test specimen 10 is asked for, wherein Δ L represents concrete sample
Elongation, Δ u are represented at the time of test specimen starts to occur tensile stress to the variable quantity of speed in the time interval of fracture, are logical
The pattern fits that the accelerometer of free end 11 is collected are crossed to draw；
According further to formula σ=E ε, stress is extrapolated
(5) according to formulaCalculate strain rate, wherein tpRepresent test specimen start to occur tensile stress when
It is carved into the time interval of fracture；Wherein, σ refers to stress, and E refers to the dynamic modulus of elasticity, tpRepresent that test specimen starts to occur stretching to answer
To the time interval of fracture at the time of power；
(6) size that the bullet 40 injects air pressure is adjusted, above-mentioned (3)-(5) step is repeated, asks for respectively not
It is the strain rate under the conditions of different strain rate with air pressure conditions, the axle center tension for finally drawing described concrete axial test specimen 10 is strong
Degree-strain rate relation curve, as shown in Figure 5.
Preferably, 3 groups of foil gauges 50 are provided with the impingement distance end of test specimen 10, are separately positioned on the test specimen 10
At impingement distance end 100mm, 200mm, 300mm.
Wherein, the foil gauge 50 in described every group is serially connected, then every group of foil gauge 50 and described bridge box 60
Respective input is serial respectively to be connected, then bridge box 60 is serially connected with data acquisition unit instrument 70.
Preferably, the size of described concrete axial test specimen 10 is diameter 74mm, length 500mm.
Preferably, the length of the bullet 40 is 100mm.
The present invention principle be：Transmission bar in original Hopkinson experimental provision is removed, and in the freedom of test specimen
Accelerometer is pasted at end, and the ripple then monitored by accelerometer analyzes the acceleration of concrete sample free end
Degree, the speed of test specimen free end surface being calculated by acceleration signal, to ensure accurately to measure test specimen free end
Speed, then can measure the tensile strength in concrete axle center by calculating analysis.
Claims (5)
1. a kind of concrete axial tensile strength measuring method based on Hopkinson principle, is entered using Hopkinson pressure bar device
Row concrete sample (10) axial tensile strength measurement, including concrete sample (10), incident bar (20), bullet (40), should
Become piece (50), it is characterised in that：
Remove the transmission bar in described Hopkinson pressure bar device；Set at described concrete sample (10) impingement distance end
It is equipped with array foil gauge (50)；In the free end of concrete sample (10) (11), an accelerometer (30) is set；By described
The Acceleration pulse map analysis that is monitored of accelerometer (30) draw the acceleration of concrete sample (10) free end (11)；
The speed on concrete sample (10) free end (11) surface is calculated；Measure the speed of concrete sample (10) free end (11)
Degree, the tensile strength in described concrete sample (10) axle center is then measured by calculating analysis；
Comprise the following steps：
(1) accelerometer (30) is set in concrete sample (10) free end (11), and passes through a bridge box (60) and one
Individual data collecting instrument (70) is connected；
(2) vertical plane of described incident bar (20) butt end and the perpendicular end surface at the shock end of concrete sample (10) are fitted in
Together；
(3) end of incident bar (20) is hit with the bullet (40), is strained by the array set on concrete sample (10)
Piece (50) measures the strain waveform figure passed in concrete sample (10), and measures concrete with described accelerometer (30) and try
The Acceleration pulse figure of part (10) free end (11)；
(4) by the array foil gauge (50) measured by strain waveform figure, according to formulaCalculate wave velocity C0, its
In, L is the length of concrete sample (10), and Δ t refers to that incidence wave enters concrete sample (10) and arrives concrete sample (10) certainly
The time spent in by holding；
Then according to formulaThe dynamic elastic modulus E of concrete is calculated, wherein E refers to the dynamic elasticity of concrete
Modulus, ρ refer to the density of concrete sample (10)；
According to formulaThe dependent variable ε of the concrete sample (10) is asked for, wherein Δ L represents concrete examination
The elongation of part (10), Δ u are represented at the time of concrete sample (10) starts to occur tensile stress to the time interval of fracture
The variable quantity of interior speed, it is that the Acceleration pulse figure fitting collected by the accelerometer of free end (11) is drawn；
According further to formula σ=E ε, stress is extrapolated
(5) according to formulaCalculate strain rate, wherein tpRepresent that concrete sample (10) starts to occur stretching to answer
To the time interval of fracture at the time of power；Wherein, σ refers to stress, and E refers to the dynamic modulus of elasticity, tpRepresent concrete sample
(10) to the time interval of fracture at the time of starting to occur tensile stress；
(6) size that the bullet (40) injects air pressure is adjusted, above-mentioned (3)-(5) step is repeated, asks for respectively in difference
Air pressure conditions are the strain rate under the conditions of different strain rate, finally draw axial tensile strength-strain of concrete sample (10)
Rate relation curve.
2. a kind of concrete axial tensile strength measuring method based on Hopkinson principle according to claim 1, its
It is characterised by：3 groups of foil gauges (50) are provided with described concrete sample (10) impingement distance end, are separately positioned on coagulation
At native test specimen (10) impingement distance end 100mm, 200mm, 300mm.
3. a kind of concrete axial tensile strength measuring method based on Hopkinson principle according to claim 1 or 2,
It is characterized in that：Foil gauge (50) in described every group is serially connected, then every group of foil gauge (50) and described bridge box
(60) respective input is serial respectively to be connected, then bridge box (60) is serially connected with data collecting instrument (70).
4. a kind of concrete axial tensile strength measuring method based on Hopkinson principle according to claim 1, its
It is characterised by：The size of described concrete sample (10) is diameter 74mm, length 500mm.
5. a kind of concrete axial tensile strength measuring method based on Hopkinson principle according to claim 1, its
It is characterised by：The length of the bullet (40) is 100mm.
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| CN201510237759.6A CN104913988B (en) | 2015-05-11 | 2015-05-11 | Concrete axial tensile strength measuring method based on Hopkinson principle |
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| CN104913988B true CN104913988B (en) | 2018-03-30 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106093194B (en) * | 2016-06-03 | 2019-07-12 | 河海大学 | The test device and amount sign method for lower quasi-brittle material stress wave attentuation rule of exploding |
| CN105928808B (en) * | 2016-07-01 | 2018-06-15 | 河海大学 | The measurement of quasi-brittle material spallation strength and determining method under a kind of high strain-rate |
| CN107228802A (en) * | 2017-06-15 | 2017-10-03 | 东北大学 | A kind of SHPB devices and its application method for obtaining half-sine wave under different loading speeds |
| CN116380619B (en) * | 2022-12-26 | 2024-02-27 | 中国人民解放军军事科学院国防工程研究院工程防护研究所 | Method for determining residual spalling strength of steel fiber concrete under repeated impact load |
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| EP0849583A1 (en) * | 1996-12-12 | 1998-06-24 | European Community | Split Hopkinson bar testing apparatus |
| CN102879261A (en) * | 2012-09-28 | 2013-01-16 | 北京理工大学 | Reluctance-type miniature Hopkinson tension and pressure integrated bar device |
| CN103134750A (en) * | 2013-02-01 | 2013-06-05 | 河海大学 | Steel bar drawing testing device suitable for Hopkinson pressure bar |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0849583A1 (en) * | 1996-12-12 | 1998-06-24 | European Community | Split Hopkinson bar testing apparatus |
| CN102879261A (en) * | 2012-09-28 | 2013-01-16 | 北京理工大学 | Reluctance-type miniature Hopkinson tension and pressure integrated bar device |
| CN103134750A (en) * | 2013-02-01 | 2013-06-05 | 河海大学 | Steel bar drawing testing device suitable for Hopkinson pressure bar |
Non-Patent Citations (1)
| Title |
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| "活性粉末混凝土冲击拉伸试验研究";孙伟等;《广州大学学报（自然科学版）》;20110228;第10卷(第1期);第42-47页 * |
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Effective date of registration: 20210422 Address after: 710000, No. eight, No. 18 East Road, Yanta District, Shaanxi, Xi'an Patentee after: POWERCHINA NORTHWEST ENGINEERING Co.,Ltd. Patentee after: HOHAI University Address before: 211100 Jiangsu City, Jiangning Province Development Zone, West Road, No. 8 Buddha Patentee before: HOHAI University |
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| CB03 | Change of inventor or designer information | ||
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Inventor after: Yang Dangfeng Inventor after: Deng Hengxin Inventor after: Su Feng Inventor after: Liu Xiaodong Inventor after: Huang Yong Inventor after: Chen Xudong Inventor after: Chen Chen Inventor after: Shao Yu Inventor after: Xu Lingyu Inventor after: Sheng Ruqing Inventor before: Chen Xudong Inventor before: Chen Chen Inventor before: Shao Yu Inventor before: Xu Lingyu Inventor before: Sheng Ruqing Inventor before: Deng Hengxin |
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| CF01 | Termination of patent right due to non-payment of annual fee | ||
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Granted publication date: 20180330 Termination date: 20210511 |