CN108195725A - Particulate matter one-dimension stress wane attenuation effect assay method based on SHPB - Google Patents
Particulate matter one-dimension stress wane attenuation effect assay method based on SHPB Download PDFInfo
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- CN108195725A CN108195725A CN201711327125.5A CN201711327125A CN108195725A CN 108195725 A CN108195725 A CN 108195725A CN 201711327125 A CN201711327125 A CN 201711327125A CN 108195725 A CN108195725 A CN 108195725A
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
Abstract
The present invention discloses a kind of particulate matter one-dimension stress wane attenuation effect assay method based on SHPB, includes the following steps：(10) stress-wave loading：Candidate particles substance test specimen is placed in split hopkinson press bar, record ejected wave, back wave, transmitted wave；(20) front end peak stress calculates：Test specimen front end peak stress is calculated；(30) boundary coefficient obtains：Fitting obtains the functional expression that functional expression and the transmission coefficient stress as suffered by test specimen that reflectance factor stress as suffered by test specimen is expressed are expressed；(40) tail end peak stress calculates：According to transmitted wave peak stress and transmission coefficient, test specimen tail end peak stress is calculated；(50) attenuating shock wave ratio obtains：According to test specimen tail end peak stress and test specimen front end peak stress, the attenuating shock wave ratio of candidate particles substance test specimen is calculated.The particulate matter one-dimension stress wane attenuation effect assay method of the present invention, result of the test is accurate, piece lengths are adjustable, test efficiency is high.
Description
Technical field
The invention belongs to material dynamic mechanical performance test technical field, particularly a kind of result of the test is accurate, test specimen is long
Spend adjustable, test efficiency it is high based on SHPB (split hopkinson press bar, Split Hopkinson Pressure Bar,
SHPB particulate matter one-dimension stress wane attenuation effect assay method).
Background technology
Have benefited from loose, porous, the squeezable characteristic of granule medium, it, can table when stress wave is propagated in granule medium
Reveal significant attenuation characteristic.As wave absorption material, granule medium is typically used to construct the wave absorption Distribution Layer of protection works, uses
To absorb, the huge energy of dissipation blast wave.Therefore, Explosive stress wave propagation attenuation in granule medium is quantitatively measured to advise
Rule, provides theoretical foundation, it appears most important for protection works type selecting and design and construction.
The experiment loading method of one-dimensional stress wave attenuation is varied in existing research granule medium, and such as shock tube is fallen
Hammer, pendulum etc..These methods generally obtain the stress wave signal in test specimen, but due to wave by stress meter embedding in sand
The difference of impedance, stress meter are difficult the actual stress state in accurate response sand, and the presence of stress meter, will necessarily be to test specimen
The propagation of medium wave impacts.Have the result shows that, the method for embedding stress meter is even as high as the test error of peak stress
20%.
Split hopkinson press bar (Split Hopkinson Pressure Bar, SHPB) is that a kind of measurement material moves
The device of state mechanical property, it can be translated by the stress wave in two elastic bars of measurement by time domain, indirect and accurate
Reflect the stress state in test specimen two ends face, " SHPB automatically tests bar Impulsive load and fills under hot conditions such as Chinese invention patent
Put " (application number：201310684780.1 publication date：2014.3.26 authorized announcement date：2015.12.30).If by SHPB
Applied to the attenuation for measuring stress wave in granule medium, harmful effect caused by embedding stress meter method will be avoided, such as China
Patent of invention " particulate matter one-dimension stress wane attenuation effect experimental rig " (application number：201720131888.1 publication date：
2017.2.14 authorized announcement date：2017.9.1).However, different from tradition SHPB material experiments, for probe into stress wave
The propagation law of one way in test specimen, within the tried time, not multiple reflections of the allowable stress wave inside test specimen, test specimen two ends are not
There are stress equilibriums.Also, the wave impedance of sand sample is not constant, can not it is directly accurate by transmitted wave in transmission bar and
The stress state of test specimen tail portion is directly calculated.
In short, problem of the existing technology is：To the measure result of the test of particulate matter one-dimension stress wane attenuation effect
Inaccuracy, piece lengths are non-adjustable, test efficiency is low.
Invention content
The purpose of the present invention is to provide a kind of particulate matter one-dimension stress wane attenuation effect assay method based on SHPB,
Result of the test is accurate, piece lengths are adjustable, test efficiency is high.
Realize the object of the invention technical solution be：
A kind of particulate matter one-dimension stress wane attenuation effect assay method based on SHPB, includes the following steps：
(10) stress-wave loading：Candidate particles substance test specimen is placed in the testing position of split hopkinson press bar, is sent out
It penetrates bullet, records the transmitted wave in incidence wave in incident bar, back wave and transmission bar；
(20) front end peak stress calculates：According to the incidence wave peak stress and back wave obtained by incidence wave, back wave
Test specimen front end peak stress is calculated in peak stress；
(30) boundary coefficient obtains：Using incidence wave and back wave, fitting obtains the reflection system of incident bar-test specimen interface
The functional expression that number stress as suffered by test specimen is expressed, and according to the phase of reflectance factor and the transmission coefficient of test specimen-transmission bar interface
Mutual relation obtains the functional expression that transmission coefficient stress as suffered by test specimen at test specimen-transmission bar interface is expressed；
(40) tail end peak stress calculates：Transmitted wave peak stress is obtained by transmitted wave, according to transmitted wave peak stress and
Test specimen tail end peak stress is calculated in transmission coefficient；
(50) attenuating shock wave ratio obtains：According to test specimen tail end peak stress and test specimen front end peak stress, it is calculated to be measured
The attenuating shock wave ratio of grain substance test specimen.
Compared with prior art, the present invention its remarkable advantage is：
1st, experimental provision new opplication：The new approaches that experimental study is carried out based on SHPB devices are opened up, previous SHPB is only used
In mechanical property of the measurement material under high strain-rate, and it is applied to measure in granule medium process provides one kind and answers
The new approaches of Reeb attenuation；
2nd, suitable for particulate matter：Suitable for a variety of materials by it is laterally limiting when stress wave attentuation test, particularly with
Particulate matter is applicable in the most；
3rd, it is accurate to the result of calculation of test specimen two ends peak stress, compared to previous common stress meter embedding in test specimen
The method for measuring stress wave attentuation in particulate matter, this method is mismatched there is no stress meter with test specimen wave impedance, stress meter pair
The problems such as stress wave propagation in test specimen generates interference.This method is applied to measure the attenuation effect of stress wave in granule medium
When, quantitatively accurate result can be obtained；
4th, piece lengths are adjustable：By changing piece lengths, stress wave can be obtained when propagating to different distance, tried
Attenuation rate in part, the relational expression changed so as to the attenuation rate for obtaining stress wave with propagation distance；
5th, it is efficient：Three waves (the incidence wave σ in incident bar only by being recorded in barBI, back wave σBRIn transmission bar
Transmitted wave σBT) peak stress in test specimen two ends portion is calculated, it is simple direct, convenient and reliable, test efficiency can be greatly improved.
The present invention is described in further detail with reference to the accompanying drawings and detailed description.
Description of the drawings
Fig. 1 is the main flow chart of the particulate matter one-dimension stress wane attenuation effect assay method the present invention is based on SHPB.
Fig. 2 is the schematic diagram that particulate matter test specimen is positioned over split hopkinson press bar (SHPB).
In figure, 1 bullet, 2 incident bars, 3 transmission bars, 4 absorbing rods, 5 sleeves, 51 particulate matters, 52,53 cushion blocks, 61 first
Foil gauge, 62 second foil gauges, 71 first this electric bridge of Huitong, 72 second this electric bridge of Huitong, 8 amplifiers, 9 oscillographs.
Specific embodiment
As shown in Figure 1, the present invention is based on the particulate matter one-dimension stress wane attenuation effect assay method of SHPB, including as follows
Step：
(10) stress-wave loading：Candidate particles substance test specimen is placed in the testing position of split hopkinson press bar, is sent out
It penetrates bullet, records the transmitted wave in incidence wave in incident bar, back wave and transmission bar；
Candidate particles substance test specimen is the long test specimen of granule medium assembled by sleeve and cushion block.
The uniformity that the granule medium tested need to meet material assumes.The purpose of this method is should in research granule medium
The attenuation of Reeb, by it macroscopically as a kind of investigation of materials, but due to the thin granular size seen of granule medium in itself not
Uniformity, this just needs test specimen being sized to sufficiently large (generally 10 times of the largest particles) in each dimension, to ensure
The stress uniformity of each axial cross section of test specimen.
The sleeve needs certain rigidity and thickness so that test specimen meets the hypothesis of uniaxial train state.
The granule medium test specimen need to meet long test specimen and assume.Piece lengths L answers long enough, to ensure in experimental period t
Interior, stress wave areflexia in test specimen is superimposed, and if velocity of wave is C in test specimen, then this hypothesis is represented by t<2L/C, i.e. stress wave
A time back and forth is propagated in test specimen more than the experiment effectively measurement time.
(20) front end peak stress calculates：According to the incidence wave peak stress and back wave obtained by incidence wave, back wave
Test specimen front end peak stress is calculated in peak stress；
(20) front end peak stress is calculated in step, and test specimen front end peak stress is calculated by following formula and obtained：
σSI-peak=σBI-peak+σBR-peak,
In formula, σSI-peakFor test specimen front end peak stress of the test specimen in incident bar-test specimen interface, σBI-peakFor incidence wave
Peak stress, value is by incidence wave σBIAnd it obtains, σBR-peakFor back wave peak stress, value is by back wave σBRAnd it obtains.
(30) boundary coefficient obtains：Using incidence wave and back wave, fitting obtains the reflection system of incident bar-test specimen interface
The functional expression that number stress as suffered by test specimen is expressed, and according to the phase of reflectance factor and the transmission coefficient of test specimen-transmission bar interface
Mutual relation obtains the functional expression that transmission coefficient stress as suffered by test specimen at test specimen-transmission bar interface is expressed；
(30) the boundary coefficient obtaining step includes：
(31) reflectance factor obtains：The reflectance factor F of incident bar-test specimen interface1(σ) is represented by suffered by test piece end
The function of axial stress σ, therefore data fitting F is carried out as the following formula1(σ) function
F1(σ)=σBR/σBI,
Wherein, on incident bar-test specimen interface, the value of σ is equal to test specimen front end incidence wave σSI, σSIBy formula σSI=σBI+σBR
It obtains.
(32) transmission coefficient obtains：The transmission coefficient t of test specimen-transmission bar interface is obtained as the following formula2(σ),
F1(σ)+T2(σ)=1.
(40) tail end peak stress calculates：Transmitted wave peak stress is obtained by transmitted wave, according to transmitted wave peak stress and
Test specimen tail end peak stress is calculated in transmission coefficient；
The transmission coefficient t of test specimen-transmission bar interface2(σ) is represented by the function of axial stress σ suffered by test piece end,
On this interface, the value of σ is equal to transmitted wave σBT。
Therefore (40) the tail end peak stress is calculated in step, test specimen tail end peak stress is calculated by following formula and obtained：
σST-peak=σBT-peak/T2(σBT-peak),
In formula, σST-peakFor test specimen tail end peak stress, σBT-peakFor transmitted wave peak stress, by transmitted wave σBTAnd obtain,
T2(σBT-peak) it is transmitted wave peak stress σBT-peakCorresponding transmission coefficient.
(50) attenuating shock wave ratio obtains：According to test specimen tail end peak stress and test specimen front end peak stress, it is calculated to be measured
The attenuating shock wave ratio of grain substance test specimen.
(50) the attenuating shock wave ratio obtaining step is specially：
K=σST-peak/σSI-peak× 100%,
In formula, k is attenuating shock wave ratio, reflects one-dimension stress wane attenuation effect.
As shown in Fig. 2, SHPB devices used by this method, enter including what is sequentially coaxially set along 1 exit direction of bullet
Bar 2, transmission bar 3 and absorbing rod 4 are penetrated, further includes sleeve 5, the 5 built-in particulate matter 51 of sleeve, 5 one end pine of sleeve is matched
On incident bar 2, other end loose fit is sleeved on transmission bar 3 trap.
The first foil gauge 61 is posted on the incident bar 2, output terminal passes through this electric bridge 71 of the first Huitong and amplifier 8
Electrical connection；The second foil gauge 62 is posted on the transmission bar 3, output terminal passes through 8 electricity of this electric bridge 72 of the second Huitong and amplifier
Connection；The amplifier 8 is electrically connected with oscillograph 9.
Incidence wave σ in the incident barBI, back wave σBRWith the transmitted wave σ in transmission barBTIt is recorded by oscillograph 9.
Laboratory operating procedures are：
1st, candidate particles media samples are assembled, and the test specimen assembled is placed in separate type Hope gold using sleeve, gasket
The testing position of gloomy compression bar, in experiment wait state；
2nd, emission bullet 1, on-test, record the incidence wave σ in incident bar on oscillograph 9BI, back wave σBRWith it is saturating
Penetrate the transmitted wave σ in barBT；
3rd, by formula σSI-peak=σBI-peak+σBR-peakPeak stress of the test specimen at incident bar-test specimen interface is calculated
σSI-peak；
4th, by σBIAnd σBRBy formula F1(σ)=σBR/σBIRelationship carry out data fitting, obtain F1(σ) expression formula；
5th, by relational expression F1(σ)+T2(σ)=1 obtains T2The expression formula of (σ)；
6th, by the peak stress σ of transmitted waveBT-peakBring formula σ intoST-peak=σBT-peak/T2(σBT-peak), it obtains test specimen and is trying
The peak stress σ of part-transmission bar interface BST-peak；
7th, calculated σSI-peakWith σST-peak, bring formula k=σ intoST-peak/σSI-peak× 100%, acquisition
The attenuating shock wave ratio of granule medium test specimen.
Claims (5)
1. a kind of particulate matter one-dimension stress wane attenuation effect assay method based on SHPB, which is characterized in that including walking as follows
Suddenly：
(10) stress-wave loading：Candidate particles substance test specimen is placed in the testing position of split hopkinson press bar, transmitting
Bullet records the incidence wave in incident bar, the transmitted wave in back wave and transmission bar；
(20) front end peak stress calculates：According to the incidence wave peak stress and back wave peak value obtained by incidence wave, back wave
Test specimen front end peak stress is calculated in stress；
(30) boundary coefficient obtains：Using incidence wave and back wave, fitting obtain the reflectance factor of incident bar-test specimen interface by
The functional expression that stress suffered by test specimen is expressed, and according to the mutual pass of reflectance factor and the transmission coefficient of test specimen-transmission bar interface
System obtains the functional expression that transmission coefficient stress as suffered by test specimen at test specimen-transmission bar interface is expressed；
(40) tail end peak stress calculates：Transmitted wave peak stress is obtained by transmitted wave, according to transmitted wave peak stress and transmission
Test specimen tail end peak stress is calculated in coefficient；
(50) attenuating shock wave ratio obtains：According to test specimen tail end peak stress and test specimen front end peak stress, candidate particles object is calculated
The attenuating shock wave ratio of matter test specimen.
2. assay method according to claim 1, which is characterized in that (20) front end peak stress is calculated in step,
Test specimen front end peak stress is calculated by following formula and obtained：
σSI-peak=σBI-peak+σBR-peak,
In formula, σSI-peakFor test specimen front end peak stress of the test specimen in incident bar-test specimen interface, σBI-peakFor incident crest value
Stress, value is by incidence wave σBIAnd it obtains, σBR-peakFor back wave peak stress, value is by back wave σBRAnd it obtains.
3. assay method according to claim 2, which is characterized in that (30) the boundary coefficient obtaining step includes：
(31) reflectance factor obtains：The reflectance factor F of incident bar-test specimen interface1(σ) is represented by axial suffered by test piece end
The function of stress σ, therefore data fitting F is carried out as the following formula1(σ) function
F1(σ)=σBR/σBI,
Wherein, on incident bar-test specimen interface, the value of σ is equal to test specimen front end incidence wave σSI, σSIBy formula σSI=σBI+σBRIt obtains.
(32) transmission coefficient obtains：The transmission coefficient t of test specimen-transmission bar interface is obtained as the following formula2(σ),
F1(σ)+T2(σ)=1.
4. assay method according to claim 3, which is characterized in that the transmission coefficient t of test specimen-transmission bar interface2(σ)
The function of axial stress σ suffered by test piece end is represented by, on this interface, the value of σ is equal to transmitted wave σBT, therefore (40)
Tail end peak stress is calculated in step, and test specimen tail end peak stress is calculated by following formula and obtained：
σST-peak=σBT-peak/T2(σBT-peak),
In formula, σST-peakFor test specimen tail end peak stress, σBT-peakFor transmitted wave peak stress, by transmitted wave σBTAnd it obtains, T2
(σBT-peak) it is transmitted wave peak stress σBT-peakCorresponding transmission coefficient.
5. according to the assay method described in claim (4), which is characterized in that (50) the attenuating shock wave ratio obtaining step is specially：
K=σST-peak/σSI-peak× 100%,
In formula, k is attenuating shock wave ratio, reflects one-dimension stress wane attenuation effect.
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| CN112098241A (en) * | 2020-09-14 | 2020-12-18 | 中国矿业大学(北京) | Energy consumption measuring system and measuring and calculating method for crushing of particulate matters |
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