CN110411862A - Test device and test method for torsion mechanical property of the test material under middle strain rate - Google Patents
Test device and test method for torsion mechanical property of the test material under middle strain rate Download PDFInfo
- Publication number
- CN110411862A CN110411862A CN201810402275.6A CN201810402275A CN110411862A CN 110411862 A CN110411862 A CN 110411862A CN 201810402275 A CN201810402275 A CN 201810402275A CN 110411862 A CN110411862 A CN 110411862A
- Authority
- CN
- China
- Prior art keywords
- bar
- incident
- test
- torsional wave
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/26—Investigating twisting or coiling properties
Abstract
The present invention provides a kind of test device of torsion mechanical property for test material under middle strain rate, including torsional wave loading unit, waveguide bar unit and data acquisition unit, the waveguide bar unit includes spaced incident bar and transmission bar, the incident bar receives the torsional wave loaded by the torsional wave loading unit, the data acquisition unit includes multipair foil gauge and data collector, multipair foil gauge is respectively connected to the data collector, to acquire the strain signal of the incident bar Yu the transmission bar by the data collector.Test device and test method of the present invention realize the load using Hopkinson bar experimental provision to strain rate in the progress of test material sample, so that the torsion mechanical property for testing each material under middle strain rate is possibly realized；Furthermore pulsewidth caused by the torsional wave loading unit in the test device is longer, it is sufficient to so that test material sample obtains sufficiently large strain under middle strain rate.
Description
Technical field
The present invention relates to material mechanical performance the field of test technology, and particularly a kind of stress wave based on electromagnetic force is sent out
The test device and test method for capableing of torsion mechanical property of the test material under middle strain rate of generating apparatus.
Background technique
Material stress in actual engineer application be it is sufficiently complex, the strain rate range of deformation is from 10-9~
107s-1It differs, therefore just needs to be grasped mechanical characteristic of the material under each strain rate.Wherein strain rate is 10-9~10-5s-1
When, the main method of test material mechanical property is using creep testing machine；Strain rate is 10-5~100s-1When, the test of use
Method is traditional hydraulic dynamometer；Strain rate is 103~105s-1When, most popular experimental technique is Hopkinson bar
Experimental technique.It in addition to this, is 10 in strain rate0~103s-1Middle low strain dynamic rate under, traditional experimental provision be drop hammer test
Machine, rotary flyweights testing machine and cam plastometer etc.；Mechanics performance of the material under different stresses is different, but is passed
The loaded-up condition that the middle low strain dynamic rate experimental provision of system applies material is relatively simple, therefore the test under middle low strain dynamic rate at present
Method is still quite incomplete.Static hydraulic dynamometer and Hopkinson bar also due to its device itself limitation, it is difficult to it is right
The load of low strain dynamic rate in sample progress.
Loading method of traditional Hopkinson bar due to its Mechanical Driven, the model of generated stress wave amplitude and pulsewidth
Enclose extremely limited, therefore the driving method for improving traditional Hopkinson bar is necessary.Hubert A Schmitt et al.
Electromagnetic riveting technology is studied, and has applied for patent (United States Patent (USP): on May 7th, 3961739,1974), later
Zieve Peter et al. has developed low voltage electromagnetic riveting technology (European patent: on May 27th, 0293257,1988), compensates for
High-voltage electromagnetic is riveted on riveting quality and promotes and applies defect existing for aspect.Application No. is 201420098605.4 Hes
In the patent of 201410161610.X, proposes directly apply to electromagnetic riveting device in Hopkinson pressure bar device respectively
Equipment scheme and experimental method, but the waveform that the method obtains has limitation.Application No. is 201410171963.8 Hes
A kind of stretching based on electromagnetic force and compression stress wave producer are proposed in 201410171963.8 two innovation and creation
Experimental provision and application method, but both scenario-frames are more complicated, and traditional pulse shaping technique can not be applied to
Pulled out condition.In order to improve this defect, then in the innovation and creation application No. is 201510956545.4, it is proposed that a kind of
New load rifle structure, the structure both can produce tensile wave and compressional wave, and traditional Training system can be used to wave
Shape carries out shaping.In the innovation and creation application No. is 201510051071, a kind of main line of electromagnetic type experimental provision is proposed
Coil structures and application method, to improve the variation range of amplitude caused by electromagnetic type experimental provision and pulse width.
Presently, if (strain rate range is 10 for strain rate experiment in being carried out using Hopkinson bar experimental provision0~
103s-1), sample can be made to obtain the strain of sufficient deformation in order to obtain, stress wave shape caused by Hopkinson bar should
Have the characteristics that low amplitude value, long pulsewidth, wherein pulsewidth length should be between 1ms~10ms.It is driven suddenly traditional by air pressure
In Pu Jinsen bar loading device, to reach so long pulsewidth, required bullet length is at several meters or so.And long pulsewidth stress wave
When being propagated in Hopkinson bar, the strain signal of record incidence wave and back wave for clarity, required incident pole length
At least twice of bullet length, this length for allowing for whole device even have more than ten meters of length, this is clearly unrealistic
's.Therefore, the data acquisition that Hopkinson bar is tested under middle strain rate is also an important problem.
Summary of the invention
The present invention is directed to propose a kind of stress wave generating device based on electromagnetic force can test material in middle strain rate
Under torsion mechanical property test device and test method.
In order to achieve the above object, the present invention provides the following technical solutions:
Test device of the present invention for torsion mechanical property of the test material under middle strain rate, comprising:
Torsional wave loading unit, for loading torsional wave to waveguide bar unit；
Waveguide bar unit, the torque rod including a pair of coaxial arrangement, is respectively incident bar and transmission bar, the incidence
One end of bar is connected with the torsional wave loading unit, to receive the torsional wave loaded by the torsional wave loading unit,
An interval is formed between the other end of the incident bar and the transmission bar；And
Data acquisition unit, including a pair of of incident bar foil gauge, a pair of of transmission bar foil gauge and data collector,
In, the pair of incident bar foil gauge and the pair of transmission bar foil gauge are pasted on the incident bar and the transmission bar respectively
Surface, two pairs of foil gauges are respectively connected to the data collector, with by the data collector acquire the incident bar with
The strain signal of the transmission bar.
Further, the torsional wave loading unit is electromagnetic drive split-Hopkinson torsional bar loading unit comprising torsion
Wave load rifle, power supply and the electric energy storage being connect respectively with torsional wave load rifle and the power supply and release, it is described
Electric energy storage and release include multiple pulsed capacitances being arranged in parallel, and the electric energy storage and release are obtained by the power supply
Electric energy is obtained, to discharge after charging complete to torsional wave load rifle, described in driving for the charging of the multiple pulsed capacitance
Torsional wave loads rifle and loads torsional wave to the waveguide bar unit；The charging and discharging of each pulsed capacitance are by electronic cutting
Close control.
Further, the electric energy storage and release include 10 pulsed capacitances being arranged in parallel, the pulsed capacitance
Voltage rating be 3000 volts, rated capacity 4mF；The charging and discharging of each pulsed capacitance are controlled by electronic switch.
Further, the incident bar and transmission bar bar cylindrical；The length of the incident bar and described
The length for penetrating bar is identical, and the length of the incident bar is less than the torsional wave loaded via the torsional wave loading unit
The a quarter of pulsewidth length and the torsional wave velocity of wave product；The diameter of the incident bar is identical as the diameter of the transmission bar
It is identical.
Further, it is 50cm that the incident bar and the transmission bar, which are respectively length, and diameter is the titanium alloy bar of 25mm.
Further, the pair of incident bar foil gauge resistance value having the same and identical sensitivity coefficient, with symmetrical
Mode is pasted on the incident bar, and the two is accessed in a manner of being oppositely arranged in incident bar Wheatstone bridge, the incident bar favour
Further include in stone electric bridge a pair of opposing and the identical fixed resistance of resistance value, the incident bar Wheatstone bridge it is defeated
Signal is accessed in the data collector out；The pair of transmission bar foil gauge resistance value having the same and identical sensitive system
Number, is pasted in a symmetrical on the transmission bar, and the two is accessed in a manner of being oppositely arranged in transmission bar Wheatstone bridge,
Further include in the transmission bar Wheatstone bridge a pair of opposing and the identical fixed resistance of resistance value, the transmission bar favour this
The output signal of energization bridge is accessed in the data collector.
Further, the pair of incident bar foil gauge is pasted on respectively at the half of the incident pole length,
Angle between setting direction and the incident rod axis is 45 °；The pair of transmission bar foil gauge is pasted on described respectively
It penetrates at the half of pole length, the angle between setting direction and the transmission rod axis is 45 °.
Further, the data acquisition unit further includes a pair of of sample foil gauge, the resistance value of the two with it is sensitive
Coefficient is identical, and the pair of sample foil gauge is accessed in sample Wheatstone bridge by conducting wire, the sample Wheatstone bridge
Output signal is accessed in the data collector.
Further, the resistance value of the incident bar foil gauge, the transmission bar foil gauge and sample foil gauge is
120 Europe, sensitivity coefficient are 2.0.
On the other hand, the invention also discloses a kind of using test device as described above to material under middle strain rate
The test method that torsion mechanical property is tested, the test method include the following steps:
S01: test material sample is set between the incident bar and the transmission bar, the test material sample,
The incident bar and the transmission bar are coaxially disposed；
S02: torsional wave is loaded from the torsional wave loading unit to waveguide bar unit；
S03: torsion mechanical property parameters of the material under middle strain rate are obtained via the data acquisition unit；
S04: torsion test curve of the test material sample under middle strain rate is drawn.
Further, the torsional wave loading unit in the test device includes torsional wave load rifle, power supply and difference
The electric energy storage and release that rifle and the power supply are connect are loaded with the torsional wave, the electric energy storage includes more with release
A pulsed capacitance being arranged in parallel, the step S02 further includes following steps:
S21: the electric energy is stored using the power supply and release charges；
S22: it after electric energy storage and release are fully charged, are stored by the electric energy and release loads rifle to torsional wave
It discharges, to activate the torsional wave load rifle to generate torsional wave.
Further, the step S03 further includes following steps:
S31: the strain signal on the incident bar measured by the data acquisition unit and the transmission bar is distinguished
It is converted into the stress σ of incident rod endIFor the stress of incident rod end and the stress σ of transmission rod endT；
S32: according to formula σS=Ab(σI+σT)/2ASThe internal stress of the test material sample is calculated,
Wherein, σIFor the stress of incident rod end, σTFor the stress for transmiting rod end, σsFor the mean stress inside sample,
AbFor the sectional area of the incident bar and the transmission bar bar, AsFor the sectional area of the test material sample.
Further, the data acquisition unit further includes sample foil gauge, and the sample foil gauge is by leading
Line is connected with the data collector, and the step S01 in the test method further includes answering the sample
Become the surface that piece is pasted on the test material sample, the step S03 in the test method further includes step
S33 measures the strain stress of the test material sample by the sample foil gaugeS, and by the measured test material sample
The strain of product is recorded by the data collector.
Further, the step S04 in the test method further includes:
S41: with formula σS=Ab(σI+σT)/2ASObtained sample internal stress σSFor Y-axis, the strain of measured sample
Signal epsilonsIt maps for X-axis, to obtain middle strain rate distorting stress-strain curve of the test material sample；
S42: to the strain stress of measured test material samplesIt differentiates to the time, to obtain the test material sample
Strain rateAnd by the strain rate of the test material sampleAs Y-axis, mapped using the time as X-axis, to obtain the test
Strain rate torsional strain rate-time graph in material sample.
Compared with prior art, of the present invention for torsion mechanical property of the test material under middle strain rate
Test device and test method have the advantage that test device and test method of the present invention are realized using Hope's gold
Load of the gloomy bar experimental provision to strain rate in the progress of test material sample, so that testing each material under middle strain rate
Torsion mechanical property be possibly realized；Furthermore arteries and veins caused by the torsional wave loading unit in test device of the present invention
It is wide longer, it is sufficient to so that test material sample obtains sufficiently large strain under middle strain rate.
Detailed description of the invention
It is of the invention to from the point of view of being described below of the preferred embodiments and drawings for illustrating purport of the invention and its using
The above and other objects, features and advantages will be apparent, in the accompanying drawings:
Fig. 1 shows the test device of the present invention for torsion mechanical property of the test material under middle strain rate
Structural schematic diagram.
[main element symbol description]
Turn wave load rifle 11
111 case lid 112 of armature spindle
Load 113 stator 114 of gun housing body
115 bearing 116 of rotor
The storage of 12 electric energy of power supply and release 13
Incident bar 21
Transmission bar 22
31 transmission bar foil gauge 32 of incident bar foil gauge
33 sample foil gauge 34 of data collector
Test material sample 4
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, to the test material of the present invention that is used under middle strain rate
The test device of torsion mechanical property and the embodiment of test method in technical solution be clearly and completely described.It is aobvious
So, described embodiment is only a part of the embodiments of the present invention, instead of all the embodiments.Based on reality of the invention
Example is applied, every other embodiment obtained by those of ordinary skill in the art without making creative efforts all belongs to
In the scope of protection of the invention.
In the description of the present invention, it is to be understood that, term " center ", " transverse direction ", " longitudinal direction ", "front", "rear",
The orientation or positional relationship of the instructions such as "left", "right", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outside" is
It is based on the orientation or positional relationship shown in the drawings, is merely for convenience of description of the present invention and simplification of the description, rather than instruction or dark
Show that signified device or element must have a particular orientation, be constructed and operated in a specific orientation, therefore should not be understood as pair
The limitation of the scope of the present invention.
As shown in Figure 1, being used for torsion mechanical property of the test material under middle strain rate it illustrates of the present invention
Test device include electromagnetic type torsional wave loading unit, waveguide bar unit and data acquisition unit, wherein the electromagnetic type
Torsional wave loading unit is used to load torsional wave to the waveguide bar unit under electromagnetic drive；The waveguide bar unit includes one
It is respectively incident bar 21 and transmission bar 22, one end and the torsion of the incident bar 21 to the torque rod of coaxial arrangement
Wave loading unit is connected, so as to receive the torsional wave loaded by the torsional wave loading unit, the incident bar 21
The other end and the transmission bar 22 between be formed with an interval, so that the test material sample 4 for test is set between this
Every place；And the data acquisition unit is for obtaining torsion mechanical property parameters of the test material under middle strain rate comprising
A pair of of incident bar foil gauge 31, a pair of of transmission bar foil gauge 32 and data collector 33, wherein the pair of incident bar strain
Piece 31 and the pair of transmission bar foil gauge 32 are pasted on the surface of the incident bar 21 and the transmission bar 22 respectively, and two is corresponding
Become piece respectively through accessing in corresponding incident bar favour Stone circuit and transmission bar favour Stone circuit by conducting wire, it is described enter
The output signal for penetrating bar favour Stone circuit and transmission bar favour Stone circuit is respectively connected to the input terminal of the data collector 33, from
And the strain signal of the incident bar 21 and the transmission bar 22 is acquired by the data collector 33.
Further, the torsional wave loading unit is electromagnetic drive split-Hopkinson torsional bar loading unit comprising torsion
Wave load rifle 11, power supply 12 and the electric energy storage and release being connect respectively with torsional wave load rifle 11 and the power supply 12
Device 13, the electric energy storage include 10 pulsed capacitances being arranged in parallel with release 13, and capacitance is ordinary electromagnetic driving
3 to 5 times of split-Hopkinson torsional bar loading unit, and the charging voltage of capacitor also adds than ordinary electromagnetic driving split-Hopkinson torsional bar
The charging voltage of carrier unit is 3 to 5 times small；The electric energy storage obtains electric energy from the power supply 12 with release 13, for institute
Including 10 pulsed capacitances charging, and after charging complete to the torsional wave load rifle electric discharge, to drive the torsional wave
It loads rifle and loads torsional wave to the waveguide bar unit；The charging and discharging of 10 pulsed capacitances are by electronic switch control
System.
Preferably, the voltage rating of the pulsed capacitance is 3000 volts, rated capacity 4mF.
In a preferred embodiment of torsional wave load rifle 11 as illustrated in FIG. 1, the torsional wave
Loading unit is electromagnetic drive split-Hopkinson torsional bar loading unit, and the torsional wave load rifle 11 includes load gun housing body 113, shell
112,4 stators 114 of body lid, rotor 115 and armature spindle 111, the case lid 112 are covered on the load gun housing body 113
Both ends, the rotor 115 be set to it is described load gun housing body 113 inside, both ends are respectively arranged with armature spindle 111, institute
It states armature spindle 111 to be pierced by from the center of the corresponding case lid 112, and is fixed in case lid 112 by bearing 116
The heart, one of them in two armature spindles 111 are connect with the incident bar 21 of the waveguide bar unit, when the rotor 115 rotation,
It drives the armature spindle 111 to rotate, to load torsional wave to the waveguide bar unit；4 stators 114 are equally spaced
It is set to the inner surface of the load gun housing body 113, each stator includes stator coil, and the direction of the stator coil is in up time
The coil direction of needle direction or counter clockwise direction, the stator coil for two stators being oppositely arranged is identical, the stator coil packet
Include a pair of positive terminal and anode connector being pierced by inside the load gun housing body 113,4 pairs of positive and negative electrode connectors
It is connected by conducting wire with serial arrangement, to 4 stator coils be connected to form coil group, the coil group and the electricity
It can store and be connect with release 13 via conducting wire；The outer surface of the rotor is equally spaced embedded with 4 permanent magnets, is oppositely arranged
2 permanent magnets magnetic pole it is identical.It, can be by stored electric energy after electric energy storage is with 13 charging complete of release
4 stator coils are released to suddenly, magnetic field energy are converted electrical energy into the stator coil, to drive the rotor
Rotation, to realize electric energy to magnetic energy, conversion of the magnetic energy to mechanical energy.
Further, the incident bar 21 and the transmission bar 22 are length cylindrical made of titanium alloy material
Bar；The length of the incident bar 21 is identical as the length of the transmission bar 22, at the same the length of the incident bar 21 be less than via
The a quarter of the pulsewidth length for the torsional wave that the torsional wave loading unit is loaded and the torsional wave velocity of wave product；It is described enter
Diameter and the diameter of the transmission bar 22 for penetrating bar 21 are identical also identical.
In a preferred embodiment of incident bar 21 of the present invention, the length of the incident bar 21 is 50cm,
And a diameter of 25mm；Correspondingly, the length of the transmission bar 22 is 50cm, and its diameter is then 25mm.
Further, a pair of of incident bar foil gauge 31 included in data acquisition unit of the present invention is having the same
Resistance value and identical sensitivity coefficient, due to the incident bar cross section be circle, this to incident bar foil gauge 31 with relative to
The centrosymmetric mode in the center of circle of the circular cross section is pasted on the outer surface of the incident bar 21, and further, the two passes through
Conducting wire is accessed in a manner of being oppositely arranged in incident bar Wheatstone bridge, further includes another pair phase in the incident bar Wheatstone bridge
To setting and the identical fixed resistance of resistance value, the output end of the incident bar Wheatstone bridge number is accessed by conducting wire
According in collector 33, the output voltage of the incident bar Wheatstone bridge is transmitted in the data collector 33；It is similar
Ground, also the same resistance value having the same of a pair of of transmission bar foil gauge 32 and identical sensitive system in the data acquisition unit
Number, since the cross section of the transmission bar is also circle, this is to transmission bar foil gauge 32 then relative to the circular cross section
The centrosymmetric mode in the center of circle is pasted on the outer surface of the transmission bar 21, and further, the two is by conducting wire to be oppositely arranged
Mode access in transmission bar Wheatstone bridge, further include that another pair is oppositely arranged and resistance in the transmission bar Wheatstone bridge
It is worth identical fixed resistance, the output end of the transmission bar Wheatstone bridge is accessed in the data collector 33 by conducting wire,
The output voltage of the transmission bar Wheatstone bridge to be transmitted in the data collector 33.
Preferably, the resistance value of the incident bar foil gauge 31 is 120 Europe, and sensitivity coefficient is 2.0, and form into
The resistance value for penetrating another pair of fixed resistance of bar Wheatstone bridge is equal with the resistance value of the incident bar foil gauge 31；It is described
The resistance value of transmission bar foil gauge 32 is 120 Europe, and sensitivity coefficient is 2.0, and forms the another of transmission bar Wheatstone bridge
The resistance value of outer a pair of fixed resistance is equal with the resistance value of the transmission bar foil gauge 32.
Further, due to the manufacture craft problem of incident foil gauge, actual resistance can not reach with it is corresponding
The identical requirement of the resistance value of fixed resistance in Wheatstone bridge, in this case, for the ease of not loading institute
To each Wheatstone bridge " adjusting 0 " when stating stress wave, also access has slide rheostat in the Wheatstone bridge, not plus
When carrying the stress wave, if the input voltage of some Wheatstone bridge is not 0, possible practical operation personnel adjust as the case may be
The input voltage of the Wheatstone bridge is adjusted to " 0 " by corresponding slide rheostat.
Preferably, the pair of incident bar foil gauge 31 is pasted on respectively at the half of 21 length of incident bar,
That is, the pair of incident bar foil gauge 31 is pasted on the midpoint of the incident bar in a manner of symmetrically, and it is arranged
Angle of the direction then respectively between the incident rod axis is 45 °；Analogously, the pair of transmission bar foil gauge 32 is then
Respectively be pasted in a manner of symmetrically on the midpoint of the transmission bar, and its setting direction then respectively with the incident bar axis
Angle between line is 45 °.
When using torsion mechanical property of the test device test material of the present invention under middle strain rate, the test
The strain stress of material sample 4SHigh-speed camera can be used to measure by DIC method, can also be calculated by the data collector
It obtains, obtains the strain stressSWhen being calculated by the data collector, the data acquisition unit of the test device is into one
Step ground includes a pair of of sample foil gauge 34, and the resistance value of two sample foil gauges 34 therein is all the same with sensitivity coefficient, passes through
Conducting wire accesses in sample favour stone electricity lattice bridge, further includes that another pair is oppositely arranged in the sample Wheatstone bridge and resistance value phase
Same fixed resistance, the output end of the sample Wheatstone bridge are accessed in the data collector 33 by conducting wire, should
The output voltage of sample Wheatstone bridge is transmitted in the data collector 33.
During actual test, by test practical operation personnel by the pair of sample foil gauge 34 in a manner of centrosymmetric
It is pasted on the midpoint of test material sample 4, the angle between setting direction and the incident rod axis is 45 °.
Preferably, the resistance value of the sample foil gauge 34 is 120 Europe, and sensitivity coefficient is 2.0.
On the other hand, the invention also discloses a kind of using test device as described above to material under middle strain rate
The test method that torsion mechanical property is tested, specifically, the test method includes the following steps:
S01: test material sample 4 is adhered between the incident bar 21 and the transmission bar 22 (as shown in Figure 1), institute
Test material sample 4, the incident bar 21 and the transmission bar 22 is stated to be coaxially disposed；
S02: torsional wave is loaded from the torsional wave loading unit to waveguide bar unit；
S03: torsion mechanical property parameters of the material under middle strain rate are obtained via the data acquisition unit；
S04: torsion test curve of the test material sample 4 under middle strain rate is drawn.
Further, as shown in Figure 1, the torsional wave loading unit in the test device includes torsional wave load rifle, electricity
Source 12 and the electric energy storage being connect respectively with torsional wave load rifle and the power supply 12 and release 13, the electric energy storage
Depositing with release 13 includes multiple pulsed capacitances being arranged in parallel, and the step S02 further includes following steps:
S21: the electric energy is stored using the power supply 12 and release 13 charges；
S22: it after electric energy storage and release 13 are fully charged, are stored by the electric energy and torsional wave is added with release 13
It carries rifle to discharge, to activate the torsional wave load rifle to generate torsional wave.
Specifically, in the step S21, charged pressure should not be greater than electric energy storage and the used capacitor of release 13
Voltage rating.
In a preferred embodiment of the invention, used charging voltage is 500V.
In a preferred embodiment of torsional wave load rifle 11 as illustrated in FIG. 1, the torsional wave
Loading unit is electromagnetic drive split-Hopkinson torsional bar loading unit, and the torsional wave load rifle 11 includes load gun housing body 113, shell
112,4 stators 114 of body lid, rotor 115 and armature spindle 111, the case lid 112 are covered on the load gun housing body 113
Both ends, the rotor 115 be set to it is described load gun housing body 113 inside, both ends are respectively arranged with armature spindle 111, institute
It states armature spindle 111 to be pierced by from the center of the corresponding case lid 112, and is fixed in case lid 112 by bearing 116
The heart, one of them in two armature spindles 111 are connect with the incident bar 21 of the waveguide bar unit, when the rotor 115 rotation,
It drives the armature spindle 111 to rotate, to load torsional wave to the waveguide bar unit；4 stators 114 are equally spaced
It is set to the inner surface of the load gun housing body 113, each stator includes stator coil, and the direction of the stator coil is in up time
The coil direction of needle direction or counter clockwise direction, the stator coil for two stators being oppositely arranged is identical, the stator coil packet
Include a pair of positive terminal and anode connector being pierced by inside the load gun housing body 113,4 pairs of positive and negative electrode connectors
It is connected by conducting wire with serial arrangement, to 4 stator coils be connected to form coil group, the coil group and the electricity
It can store and be connect with release 13 via conducting wire；The outer surface of the rotor is equally spaced embedded with 4 permanent magnets, is oppositely arranged
2 permanent magnets magnetic pole it is identical.
After electric energy storage with after 13 charging complete of release, stored electric energy can be released to 4 suddenly
The stator coil generates electromagnetic repulsion force, the electricity at this time between the permanent magnet on rotor 115 and the stator coil of stator 114
Magnetic repulsion makes rotor 115 produce instantaneous torque, and the torque has traveled to incidence by armature spindle 111 in the form of torsional wave
On bar 21, so as to form incidence wave.When the incidence wave reaches the contact surface between incident bar 21 and test material sample 4,
Since wave impedance mismatches, a part of the incidence wave is reflected, and back wave is formed in incident bar 21, another part then passes through
Test material sample 4 is transmitted into transmission bar 22 and forms transmitted wave.By one-dimensional elastic stress wave propagation theory it is found that transmitted wave
After traveling to 22 end reflection of transmission bar, amplitude is doubled, and the compressional wave reaches connecing for test material sample 4 and transmission bar 22
When contacting surface, and test material sample 4 can be loaded, form new back wave and transmitted wave.And in incident bar 21, reflection
Wave can also be reflected again in loading end, and be loaded again to test material sample 4, and the process repeats always.
And in above process, it is respectively arranged at the strain on 4 surface of 21 surface of incident bar, 22 surface of transmission bar and test material sample
Piece can then occur to strain and resistance value occurs according to corresponding incident bar 21, transmission bar 22 and test material sample 4
Change.
Preferably, in order to enable the rotor 115 in torsional wave load rifle with most fast response during the test
Speed generates torsional wave, can adjust the permanent magnet on the rotor 115 before the test begins and be set to the load gun housing body
The relative position between 4 stators on 113 inner surfaces specifically can be bonded the test material sample 4 by practical operation personnel
And the rotor is rotated, so that the line between two permanent magnets on the rotor 115 with same pole be made to add with described
The angle carried between the line in gun housing body 113 between identical two stator coils of set direction is adjusted to 45 °, in this position
It sets down, when stator coil electric discharge, torque suffered by the rotor 115 is maximum, so that the rotor 115 can be with most
Fast response speed generates torsional wave.
Further, the step S03 further includes following steps:
S31: by the strain signal on the incident bar 21 measured by the data acquisition unit and the transmission bar 22
It is separately converted to the stress σ of incident rod endIFor the stress of incident rod end and the stress σ of transmission rod endT；
S32: according to formula σS=Ab(σI+σT)/2ASThe internal stress of the test material sample 4 is calculated, wherein
σIFor the stress of incident rod end, σTFor the stress for transmiting rod end, σsFor the mean stress inside sample, AbFor the incident bar 21
With the sectional area of 22 bar of transmission bar, AsFor the sectional area of the test material sample 4；
S33: the strain signal ε of the test material sample 4 is measuredS, and by the measured test material sample 4
Strain is recorded by the data collector 33.
Specifically, according to by the data acquisition unit collected incident bar favour Stone circuit output voltage signal
Obtain the stress σ of incident rod endIThe step of it is as follows:
Firstly, by data collecting instrument collected incident bar favour Stone circuit output voltage signal UIBe converted into
Penetrate the strain signal ε on barI, specific formula are as follows: εI=2UI/k/(U-UI), wherein εIFor the strain signal on incident bar, UIFor
By the data acquisition unit collected incident bar favour Stone circuit output voltage signal, k for institute answered using incident bar
Become the sensitivity coefficient of piece, U is the supply voltage of Wheatstone bridge；
Secondly, obtaining the strain signal ε on incident barIAfterwards, then by the strain signal ε on the incident barIIt is converted into incidence
Shear strain signal γ on barI, specifically, since incident bar at this time is in pure twisting states, and the incident bar foil gauge
Angle between setting direction and incident rod axis is in 45 °, according to generalized Hooke's law: γI=2 εI；
In turn, further according to the shear strain signal γ on incident barIObtain the shearing stress τ in incident barI, particular because
In stress wave transmittance process, the incident bar is always maintained at elastic stage, therefore the shearing stress τ in incident bar at this timeIFor τI=G
γI, wherein G is the modulus of shearing of incident bar；
Finally, according to the shearing stress τ in incident barIObtain the stress σ of incident rod endI, since the incident bar is in pure torsion
Turn state, the shearing stress τ in the incident barIThe stress σ of the as described incident rod endI。
Similarly, further according to by the data acquisition unit collected transmission bar favour Stone circuit output voltage signal
Obtain the stress σ of transmission rod endTThe step of it is as follows:
Firstly, by data collecting instrument collected transmission bar favour Stone circuit output voltage signal UTIt is converted into
Penetrate the strain signal ε on barT, specific formula are as follows: εT=2UT/k/(U-UT), wherein εTFor the strain signal on transmission bar, UTFor
By the data acquisition unit collected transmission bar favour Stone circuit output voltage signal, k be used transmission bar
The sensitivity coefficient of foil gauge, U are the supply voltage of transmission bar Wheatstone bridge；
Secondly, obtaining the strain signal ε on transmission barTAfterwards, then by the strain signal ε on the transmission barTIt is converted into transmission
Shear strain signal γ on barT, specifically, since transmission bar at this time is in pure twisting states, and the transmission bar foil gauge
Angle between setting direction and incident rod axis is in 45 °, according to generalized Hooke's law: γT=2 εT；
In turn, further according to the shear strain signal γ on transmission barTObtain the shearing stress τ in incident barT, particular because
In stress wave transmittance process, the transmission bar is always maintained at elastic stage, therefore the shearing stress τ in transmission bar at this timeTFor τT=G
γT, wherein G is the modulus of shearing of incident bar；
Finally, according to the shearing stress τ in transmission barTObtain the stress σ of transmission rod endT, since the transmission bar is in pure torsion
Turn state, the shearing stress τ in the transmission barTThe stress σ of the as described incident rod endT。
And need to illustrate, in formula σS=Ab(σI+σT)/2ASIn, test material sample 4 itself respectively with enter
It penetrates bar 21 and transmission bar 22 to be connected, when obtaining the stress σ of incident bar 21 Yu 4 connecting pin of test material sampleIAfterwards, can be entered
Penetrate the power A of bar 21 Yu 4 connecting pin of test material samplebσI；The power of transmission bar 22 Yu 4 connecting pin of test material sample can similarly be obtained
AbσT, it is averaged after the two power are added, then divided by the sectional area A of test material sample 4S, just obtained test material sample
The stress of product 4.
In a preferred embodiment of test method of the present invention, the strain of the test material sample 4 is believed
Number εSIt is to be measured using high-speed camera by DIC method.
Alternatively, in another preferred embodiment of test method of the present invention, the test material sample 4
Strain signal εSBe by the data acquisition unit according to the collected sample favour stone electricity lattice bridge output voltage
By what is obtained, specifically, in the test device applied by this method, the data acquisition unit further includes that sample is answered
Become piece 34, the sample foil gauge 34 is connected by conducting wire with the data collector 33, in this way, in the test method
The step S01 further includes that the pair of sample foil gauge 34 is pasted on test material sample in a manner of centrosymmetric
The midpoint of product 4, the angle between setting direction and the incident rod axis is 45 °, and in the step of the test method
In rapid S33, the strain signal ε of the test material sample 4SSpecific acquisition modes are as follows: will be by being acquired on data collecting instrument
The output voltage signal U of the sample favour stone electricity lattice bridge arrivedSThe strain signal ε being converted on transmission barS, specific formula are as follows: εS=
2US/k/(U-US), wherein εSFor the strain signal on test material sample 4, USTo be collected by the data acquisition unit
Sample favour Stone circuit output voltage signal, k be used sample foil gauge sensitivity coefficient, U be sample favour stone
The supply voltage of electric bridge.
Further, the step S04 in the test method further includes:
S41: with formula σS=Ab(σI+σT)/2ASObtained sample internal stress σSFor Y-axis, the strain of measured sample
Signal epsilonsFor X-axis mapping, middle strain rate distorting stress-strain curve of the test material sample 4 is obtained；
S42: to the strain stress of measured test material sample 4sIt differentiates to the time, to obtain the test material sample 4
Strain rateAnd by the strain rate of the test material sample 4As Y-axis, mapped using the time as X-axis, it is described to obtain
Strain rate torsional strain rate-time graph in test material sample 4.
Finally it should be noted that: the above embodiments are merely illustrative of the technical scheme of the present invention and are not intended to be limiting thereof；To the greatest extent
The present invention is described in detail with reference to preferred embodiments for pipe, it should be understood by those ordinary skilled in the art that: still
It can modify to a specific embodiment of the invention or some technical features can be equivalently replaced；Without departing from this hair
The spirit of bright technical solution should all cover within the scope of the technical scheme claimed by the invention.
Claims (14)
1. a kind of test device of the torsion mechanical property for test material under middle strain rate characterized by comprising
Torsional wave loading unit, for loading torsional wave to waveguide bar unit；
Waveguide bar unit, the torque rod including a pair of coaxial arrangement, is respectively incident bar (21) and transmission bar (22), described
One end of incident bar (21) is connected with the torsional wave loading unit, is loaded with reception by the torsional wave loading unit
Torsional wave is formed with an interval between the other end and the transmission bar (22) of the incident bar (21)；And
Data acquisition unit, including a pair of of incident bar foil gauge (31), a pair of of transmission bar foil gauge (32) and data collector
(33), wherein the pair of incident bar foil gauge (31) and the pair of transmission bar foil gauge (32) be pasted on respectively it is described enter
The surface of bar (21) Yu the transmission bar (22) is penetrated, two pairs of foil gauges are respectively connected to the data collector (33), to pass through
State the strain signal that data collector (33) acquire the incident bar (21) and the transmission bar (22).
2. test device as described in claim 1, which is characterized in that the torsional wave loading unit is electromagnetic drive Hope gold
Gloomy torsion bar loading unit comprising torsional wave loads rifle, power supply (12) and loads rifle and the electricity with the torsional wave respectively
Electric energy storage and release (13) of source (12) connection, the electric energy storage and release (13) include multiple arteries and veins being arranged in parallel
Capacitor is rushed, the electric energy storage obtains electric energy by the power supply (12) with release (13), for the multiple pulsed capacitance
Charging, to torsional wave load rifle electric discharge after charging complete, to drive the torsional wave to load rifle to the waveguide rod list
Member load torsional wave；The charging and discharging of each pulsed capacitance are controlled by electronic switch.
3. test device as claimed in claim 2, which is characterized in that electric energy storage and release (13) include 10 simultaneously
Join the pulsed capacitance of setting, the voltage rating of the pulsed capacitance is 3000 volts, rated capacity 4mF；Each pulse electricity
The charging and discharging of appearance are controlled by electronic switch.
4. test device as described in claim 1, which is characterized in that the incident bar (21) is in the transmission bar (22)
Cylindrical bar；The length of the incident bar (21) is identical as the length of the transmission bar (22), and the incident bar (21)
Length is less than the pulsewidth length and the four of the torsional wave velocity of wave product of the torsional wave loaded via the torsional wave loading unit
/ mono-；The diameter and the diameter of the transmission bar (22) of the incident bar (21) are identical also identical.
5. test device as claimed in claim 4, which is characterized in that the incident bar (21) and the transmission bar (22) are respectively
It is 50cm for length, diameter is the titanium alloy bar of 25mm.
6. test device as described in claim 1, which is characterized in that the pair of incident bar foil gauge (31) is having the same
Resistance value and identical sensitivity coefficient are pasted in a symmetrical on the incident bar (21), and the two is in a manner of being oppositely arranged
Access incident bar Wheatstone bridge in, further include in the incident bar Wheatstone bridge a pair of opposing and resistance value it is identical
The output signal of fixed resistance, the incident bar Wheatstone bridge is accessed in the data collector (33)；It is the pair of
Bar foil gauge (32) resistance value having the same and identical sensitivity coefficient are penetrated, is pasted on the transmission bar (22) in a symmetrical
On, the two is accessed in a manner of being oppositely arranged in transmission bar Wheatstone bridge, further includes a pair in the transmission bar Wheatstone bridge
The output signal of the identical fixed resistance of be oppositely arranged and resistance value, the transmission bar Wheatstone bridge is accessed the data
In collector (33).
7. test device as claimed in claim 6, which is characterized in that the pair of incident bar foil gauge (31) is pasted on respectively
At the half of incident bar (21) length, the angle between setting direction and the incident rod axis is 45 °；It is described
A pair of of transmission bar foil gauge (32) is pasted on respectively at the half of the transmission bar (22) length, setting direction with it is described
The angle transmitted between rod axis is 45 °.
8. test device as claimed in claim 7, which is characterized in that the data acquisition unit further includes a pair of of examination
Sample foil gauge (34), the resistance value of the two is identical as sensitivity coefficient, and the pair of sample foil gauge (34) accesses sample by conducting wire
In Wheatstone bridge, the output signal of the sample Wheatstone bridge is accessed in the data collector (33).
9. test device as claimed in claim 7 or 8, which is characterized in that the incident bar foil gauge (31), the transmission bar
The resistance value of foil gauge (32) and sample foil gauge (34) is 120 Europe, and sensitivity coefficient is 2.0.
10. it is a kind of using test device as claimed in claims 1-9 to torsion mechanical property of the material under middle strain rate into
The test method of row test, which comprises the steps of:
S01: test material sample (4) is set between the incident bar (21) and the transmission bar (22), the test material
Expect that sample (4), the incident bar (21) and the transmission bar (22) are coaxially disposed；
S02: torsional wave is loaded from the torsional wave loading unit to waveguide bar unit；
S03: torsion mechanical property parameters of the material under middle strain rate are obtained via the data acquisition unit；
S04: torsion test curve of the test material sample (4) under middle strain rate is drawn.
11. test method as claimed in claim 10, which is characterized in that the torsional wave loading unit packet in the test device
It includes torsional wave load rifle, power supply (12) and loads the electric energy that rifle and the power supply (12) are connect with the torsional wave respectively and store
With release (13), electric energy storage and release (13) include multiple pulsed capacitances being arranged in parallel, the step S02 into
Include the following steps: to one step
S21: the electric energy is stored using the power supply (12) and release (13) charges；
S22: it after electric energy storage and release (13) are fully charged, are stored by the electric energy and torsional wave is added with release (13)
It carries rifle to discharge, to activate the torsional wave load rifle to generate torsional wave.
12. test method as claimed in claim 11, which is characterized in that the step S03 further includes following steps:
S31: by the strain signal on the incident bar (21) measured by the data acquisition unit and the transmission bar (22)
It is separately converted to the stress σ of incident rod endIFor the stress of incident rod end and the stress σ of transmission rod endT；
S32: according to formula (2) σS=Ab(σI+σT)/2ASThe internal stress of the test material sample (4) is calculated, wherein
σIFor the stress of incident rod end, σTFor the stress for transmiting rod end, σsFor the mean stress inside sample, AbFor the incident bar
(21) with the sectional area of the transmission bar (22) bar, AsFor the sectional area of the test material sample (4).
13. test method as claimed in claim 12, which is characterized in that the data acquisition unit further includes sample
Foil gauge (34), the sample foil gauge (34) are connected by conducting wire with the data collector (33), the test method
In the step S01 further include the table that the sample foil gauge (34) is pasted on to the test material sample (4)
Face, the S03 step in the test method further includes step S33) it is measured by the sample foil gauge (34)
The strain stress of the test material sample (4)S, and the strain of the measured test material sample (4) is adopted by the data
Storage (33) record.
14. test method as claimed in claim 13, which is characterized in that the S04 step in the test method is into one
Step ground includes:
S41: with formula (2) σS=Ab(σI+σT)/2ASObtained sample internal stress σSFor Y-axis, the strain of measured sample
Signal epsilonsIt maps for X-axis, to obtain middle strain rate distorting stress-strain curve of the test material sample (4)；
S42: to the strain stress of measured test material sample (4)sIt differentiates to the time, to obtain the test material sample (4)
Strain rateAnd by the strain rate of the test material sample (4)As Y-axis, mapped using the time as X-axis, to obtain
State strain rate torsional strain rate-time graph in test material sample (4).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810402275.6A CN110411862A (en) | 2018-04-28 | 2018-04-28 | Test device and test method for torsion mechanical property of the test material under middle strain rate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810402275.6A CN110411862A (en) | 2018-04-28 | 2018-04-28 | Test device and test method for torsion mechanical property of the test material under middle strain rate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110411862A true CN110411862A (en) | 2019-11-05 |
Family
ID=68357163
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810402275.6A Pending CN110411862A (en) | 2018-04-28 | 2018-04-28 | Test device and test method for torsion mechanical property of the test material under middle strain rate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110411862A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111044352A (en) * | 2019-12-31 | 2020-04-21 | 太原理工大学 | Separated Hopkinson bar pressure and torsion load composite loading device and use method thereof |
| CN114965117A (en) * | 2022-05-06 | 2022-08-30 | 天津大学 | Dynamic friction experimental device and method for testing dynamic mechanical property of material |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002082031A (en) * | 2000-09-05 | 2002-03-22 | Ishikawajima Harima Heavy Ind Co Ltd | Hopkinson bar testing apparatus |
| CN103913382A (en) * | 2014-04-21 | 2014-07-09 | 西北工业大学 | Experimental device of split hopkinson pressure bar based on electromagnetic force load |
| CN104677723A (en) * | 2015-01-30 | 2015-06-03 | 西北工业大学 | Primary coil of electromagnetic stress wave generator and charging/discharging methods |
| CN104729918A (en) * | 2015-03-11 | 2015-06-24 | 赵江霞 | Dynamic pull/pressing and torsion synchronous combined loading experiment device |
| CN104897486A (en) * | 2015-05-20 | 2015-09-09 | 西北工业大学 | Electromagnetic torsional split-Hopkinson bar loading device |
| CN204758411U (en) * | 2015-05-20 | 2015-11-11 | 西北工业大学 | Electromagnetic type hopkinson torsion bar loading device twists reverse rifle |
| CN105571961A (en) * | 2015-12-18 | 2016-05-11 | 西北工业大学 | Electromagnetic induction type Hopkinson torsion and pressure bar loading device and experimental method |
| CN105651625A (en) * | 2016-01-06 | 2016-06-08 | 西北工业大学 | Loading device for disc type split-hopkinson torsional bar based on electromagnetic force and experimental method |
-
2018
- 2018-04-28 CN CN201810402275.6A patent/CN110411862A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002082031A (en) * | 2000-09-05 | 2002-03-22 | Ishikawajima Harima Heavy Ind Co Ltd | Hopkinson bar testing apparatus |
| CN103913382A (en) * | 2014-04-21 | 2014-07-09 | 西北工业大学 | Experimental device of split hopkinson pressure bar based on electromagnetic force load |
| CN104677723A (en) * | 2015-01-30 | 2015-06-03 | 西北工业大学 | Primary coil of electromagnetic stress wave generator and charging/discharging methods |
| CN104729918A (en) * | 2015-03-11 | 2015-06-24 | 赵江霞 | Dynamic pull/pressing and torsion synchronous combined loading experiment device |
| CN104897486A (en) * | 2015-05-20 | 2015-09-09 | 西北工业大学 | Electromagnetic torsional split-Hopkinson bar loading device |
| CN204758411U (en) * | 2015-05-20 | 2015-11-11 | 西北工业大学 | Electromagnetic type hopkinson torsion bar loading device twists reverse rifle |
| CN105571961A (en) * | 2015-12-18 | 2016-05-11 | 西北工业大学 | Electromagnetic induction type Hopkinson torsion and pressure bar loading device and experimental method |
| CN105651625A (en) * | 2016-01-06 | 2016-06-08 | 西北工业大学 | Loading device for disc type split-hopkinson torsional bar based on electromagnetic force and experimental method |
Non-Patent Citations (2)
| Title |
|---|
| 佟景伟等: "温度对高应变率扭-拉复合加载下形状记忆合金本构关系影响的研究", 《固体力学学报》 * |
| 薛青等: "单脉冲加载的Hopkinson扭杆装置", 《爆炸与冲击》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111044352A (en) * | 2019-12-31 | 2020-04-21 | 太原理工大学 | Separated Hopkinson bar pressure and torsion load composite loading device and use method thereof |
| CN111044352B (en) * | 2019-12-31 | 2022-02-15 | 太原理工大学 | Separated Hopkinson bar pressure and torsion load composite loading device and use method thereof |
| CN114965117A (en) * | 2022-05-06 | 2022-08-30 | 天津大学 | Dynamic friction experimental device and method for testing dynamic mechanical property of material |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105571961B (en) | Induction Hopkinson strut and tie loading device and experimental method | |
| CN108344648B (en) | Single-shaft bidirectional loading separation type Hopkinson pressure bar and pull bar device and experimental method | |
| CN108519283A (en) | A kind of dynamic mechanics parameter of material acquisition device and method | |
| CN103994922B (en) | A kind of stretching based on electromagnetic force and compression stress wave producer and experimental technique | |
| CN104897486B (en) | A kind of electromagnetic type split-Hopkinson torsional bar loading device | |
| CN103926138B (en) | Based on Hopkinson strut and tie stress wave generator and the experimental technique of electromagnetic force | |
| CN107063899B (en) | Mechanical connecting joint high speed impact experimental rig and test method | |
| CN108519296A (en) | A kind of dynamic mechanics parameter of material acquisition device and method | |
| CN105651625A (en) | Loading device for disc type split-hopkinson torsional bar based on electromagnetic force and experimental method | |
| CN108267366B (en) | Medium strain rate tension and compression bar loading experimental method | |
| CN110411862A (en) | Test device and test method for torsion mechanical property of the test material under middle strain rate | |
| CN111487119B (en) | Torsional stress wave releasing device | |
| CN111665152A (en) | Material dynamic compression circulating loading device and method thereof | |
| CN103018651B (en) | On-chip testing system of micro-electromechanical system (MEMS) device and testing method thereof | |
| CN101561342A (en) | System and method for measuring time-sharing quick steady-state sine sweep excitation frequency response function | |
| CN106052983A (en) | Elastic coupling dynamic and static torsion rigidity simple testing device and method | |
| CN102657932A (en) | Tennis racket response online detector | |
| CN103831227B (en) | A kind of change wavelength low order horizontal shear wave electromagnet ultrasonic changer | |
| CN201765262U (en) | Handheld digital storage oscilloscope | |
| CN109724687A (en) | Bending wave in a kind of vibration of measurement structure crankling vibration, torsional wave separation method | |
| CN206095563U (en) | Transformer winding axial deformation's modal experiment system | |
| CN105403748A (en) | Measurement apparatus and method for generating pulse voltages on the basis of flexoelectric dynamic effect | |
| CN203894129U (en) | Split hopkinson pressure bar experimental device | |
| CN201255744Y (en) | Piezoelectric spring probe for blast wave measurement | |
| CN110082204A (en) | A kind of twin shaft Hopkinson bar high strain rate tensile device and test method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20191105 |