CN109297812A - Three axis biaxial compressive loading methods and its system - Google Patents
Three axis biaxial compressive loading methods and its system Download PDFInfo
- Publication number
- CN109297812A CN109297812A CN201811137535.8A CN201811137535A CN109297812A CN 109297812 A CN109297812 A CN 109297812A CN 201811137535 A CN201811137535 A CN 201811137535A CN 109297812 A CN109297812 A CN 109297812A
- Authority
- CN
- China
- Prior art keywords
- compression
- sample
- rod
- cube
- stress
- 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
- 238000011068 loading method Methods 0.000 title claims abstract description 42
- 230000006835 compression Effects 0.000 claims abstract description 222
- 238000007906 compression Methods 0.000 claims abstract description 222
- 238000000034 method Methods 0.000 claims abstract description 14
- 230000002457 bidirectional effect Effects 0.000 claims description 14
- 230000000644 propagated effect Effects 0.000 abstract 1
- 239000000523 sample Substances 0.000 description 64
- 239000003990 capacitor Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 13
- 238000002474 experimental method Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000004146 energy storage Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 238000004590 computer program Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
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
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- 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
- G01N3/02—Details
-
- 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
- G01N3/02—Details
- G01N3/04—Chucks
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/003—Generation of the force
- G01N2203/005—Electromagnetic means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0075—Strain-stress relations or elastic constants
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/025—Geometry of the test
- G01N2203/0256—Triaxial, i.e. the forces being applied along three normal axes of the specimen
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/04—Chucks, fixtures, jaws, holders or anvils
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0676—Force, weight, load, energy, speed or acceleration
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The application discloses three axis biaxial compressive loading methods of one kind and its system, the method comprise the steps that three groups of compression sets are arranged according to rectangular coordinate system in space；Wherein, it any two is mutually perpendicular in the axial direction in three groups of compression sets；Wherein, every group of compression set respectively includes compression stress wave producer and constrictor；Sample is clamped by three groups of compression sets, the sample is the cube with bevelling；The compression stress wave producer of every group of compression set generates compression stress wave simultaneously, and the compression stress wave is propagated from the distal end of constrictor to the sample, with the sample described in three axisymmetrically loadeds simultaneously；The strain signal that each constrictor generates is acquired, the stress of the inside of the sample is calculated according to the strain signal.It can be realized while by application in three axis bi-directional symmetrical compression-loaded samples.
Description
Technical Field
The invention relates to a mechanical property testing technology of a material under dynamic three-axis bidirectional loading, in particular to a three-axis bidirectional compression loading method and a system thereof.
Background
In practical applications, engineering materials and structures are often subjected to various forms of loading. Many of these loads have application times on the order of milliseconds, microseconds, and even nanoseconds. When the material is subjected to the load with very short acting time, the mechanical property of the material is different from that of the material under the quasi-static condition. When the material is subjected to the impact load, the stress state of the material is quite complex, and the borne load changes obviously along the time course. Therefore, the research on the testing technology of the material under the high strain rate when the material bears the multi-axis composite loading has higher scientific research and application values.
The Hopkinson bar experimental device is one of the most widely used experimental techniques for measuring the mechanical properties of materials under high strain rate. The basic principle of this technique is: a short sample is placed between two elongated rods to load the sample. And calculating the load borne by the sample and the deformation of the sample through the pulse signals measured on the two slender rods, thereby obtaining the dynamic mechanical property of the sample material.
The three-axis composite loading of the material is realized by utilizing the Hopkinson bars, the basic principle is that three groups of uniaxial Hopkinson bar experiment devices are combined, each group of Hopkinson bars applies an axial stress wave to the sample, and the sample is loaded by the three groups of stress waves in different axial directions simultaneously, so that the dynamic mechanical property of the material in a three-axis stress state is finally obtained. Because the stress wave generating devices of each axial Hopkinson bar are independent, how to simultaneously load the sample by the stress waves in different axial directions is a very important problem. However, the conventional hopkinson bar generates stress waves in a mechanical loading mode, so that the generation time of the stress waves cannot be accurately controlled.
Disclosure of Invention
The invention mainly aims to provide a three-axis bidirectional compression loading method and a three-axis bidirectional compression loading system, which are used for solving the problem that synchronous compression loading of three-axis bidirectional stress waves cannot be realized in the prior art.
In order to solve the above problem, an embodiment of the present invention provides a three-axis bidirectional compression loading method, which includes:
three groups of compression devices are arranged according to a space rectangular coordinate system; wherein any two of the three sets of compression devices are mutually vertical in the axial direction; each group of compression devices respectively comprises a compression stress wave generator and a compression rod;
clamping a sample by the three groups of compression devices, wherein the sample is a cube with a chamfered edge;
the compression stress wave generator of each group of compression devices simultaneously generates compression stress waves, and the compression stress waves are transmitted to the sample from the far end of the compression rod so as to simultaneously and symmetrically load the sample in three axes;
and acquiring strain signals generated by the compression rods, and calculating the internal stress of the sample according to the strain signals.
Each group of compression devices are coaxially arranged according to the sequence of a compression stress wave generator, a compression rod and a compression stress wave generator; wherein the compression rod moves only in the axial direction.
Wherein, still include: providing a calibration jig for determining the axial position of the compression rod; the calibration clamp is a cube with an internal space, the centers of six faces of the cube are respectively provided with an opening, and the area of the opening is matched with the area of the cross section of the compression rod; and placing the sample into the inner space of the calibration jig, and inserting a compression rod of a compression device into the calibration jig through the through hole to hold the sample.
The internal space of the calibration fixture is a cube, and the side length of the cube is more than 2 times of that of the sample.
Wherein the strain signal comprises: incident wave signal, reflected wave signal, transmitted wave signal.
According to an embodiment of the present invention, a three-axis bidirectional compression loading apparatus is further provided, which includes:
the three groups of compression devices are arranged according to a space rectangular coordinate system; wherein any two of the three sets of compression devices are mutually vertical in the axial direction; each group of compression devices respectively comprises a compression stress wave generator and a compression rod;
a sample, which is a cube with chamfered edges, and is clamped by the three groups of compression devices; the compression stress wave generator of each group of compression devices simultaneously generates compression stress waves, and the compression stress waves are transmitted to the sample from the far end of the compression rod so as to simultaneously and symmetrically load the sample in three axes;
and the data acquisition unit is used for acquiring strain signals generated by the compression rods so as to calculate the internal stress of the sample according to the strain signals.
Each group of compression devices are coaxially arranged according to the sequence of a compression stress wave generator, a compression rod and a compression stress wave generator; wherein the compression rod moves only in the axial direction.
Wherein, still include: a calibration jig for determining an axial position of the compression rod; the calibration clamp is a cube with an internal space, the centers of six faces of the cube are respectively provided with an opening, and the area of the opening is matched with the area of the cross section of the compression rod; wherein the sample is placed in the inner space of the jig, and a compression rod of a compression device is inserted into the jig through the through hole to hold the sample.
The internal space of the calibration fixture is a cube, and the side length of the cube is more than 2 times of that of the sample.
Wherein the strain signal comprises: incident wave signal, reflected wave signal, transmitted wave signal.
According to the technical scheme of the invention, three axial loading stress wave loading systems are reasonably designed by adopting an electromagnetic loading technology, and six compression stress wave generators and corresponding compression rods are adopted, so that the three-axis bidirectional dynamic compression loading of the electromagnetic Hopkinson rod is realized, and the simultaneous three-axis symmetrical loading of the sample is realized. The method is simple to operate, stress waves with expected pulse amplitudes and expected pulse widths can be obtained in different loading directions through selection of experimental parameters, and the controllability is strong.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
FIG. 1 is a schematic diagram of a three-axis bi-directional compression loading apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic illustration of a sample according to an embodiment of the present invention;
FIG. 3A is a schematic perspective view of a calibration jig according to an embodiment of the invention;
FIG. 3B is a schematic perspective view of a portion of a calibration jig according to an embodiment of the invention;
FIG. 3C is a top view of a portion of a calibration fixture according to an embodiment of the invention;
FIG. 4 is a schematic diagram of the arrangement of a sample, a calibration jig and a compression bar according to an embodiment of the invention;
FIG. 5 is a flow chart of a three-axis bi-directional compression loading method according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a single axial direction in a three-axis compression loading experiment of a hopkinson bar according to an embodiment of the invention.
[ notation ] to show
1 compressive stress wave generator
2 compression bar
3 calibration jig
31 opening
32 screw hole
4 test specimen
5 strain gauge
6 Wheatstone bridge
7 data acquisition unit
8 stress wave synchronizer
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.
According to the embodiment of the application, the three-axis bidirectional compression loading device is used for loading a sample in three axial directions, so that dynamic mechanical property data of the material in a three-axis stress state are obtained.
The triaxial bidirectional compression loading device according to the embodiment of the application at least comprises: three sets of compression devices, samples, data collectors, described in detail below.
Referring to fig. 1, the three sets of compression devices are arranged according to a rectangular spatial coordinate system, that is, the three sets of compression devices are respectively arranged on an X axis, a Y axis and a Z axis of the rectangular spatial coordinate system, wherein any two of the three sets of compression devices are mutually perpendicular in an axial direction.
In an embodiment, the compression devices may be uniaxial bi-directional loaded hopkinson bars, as shown in fig. 1, where each group of compression devices comprises two compression stress wave generating devices 1 and two compression bars 2. Each group of compression devices are coaxially arranged according to the sequence of the compression stress wave generator 1, the compression rod 2 and the compression stress wave generator 1; wherein the compression rod 2 is only movable in the axial direction.
Three sets of compression devices in different axial directions simultaneously generate compression stress waves and synchronously load the sample. And arranging a sample at the origin of the rectangular space coordinate system, wherein the sample is clamped by the three groups of compression devices. The three groups of compression devices comprise six compression rods with the same length, the far ends of the compression rods are connected with a compression stress wave generator, and the near ends of the compression rods are in contact with the sample. The cross section of the compression rod is square, the side length of the square can be 10mm, and the length of the compression rod can be 2 m.
The principle of the compression stress wave generator is that an electric energy storage releaser is charged by a power supply, then the electric energy storage releaser is switched between a charging state and a discharging state through a switch, so that instantaneous strong current is generated, a loading gun obtains instantaneous load, and the load is transmitted to a wave guide rod to form compression stress waves. In an embodiment, the compressive stress wave generator 1 comprises: the device comprises a power supply, a compression wave capacitor charger and a compression wave loading gun. The compression wave capacitor charger adopts a power supply part of the existing electromagnetic riveting equipment, and a positive electrode output line of the output of the capacitor charger is connected with a positive electrode line of a compression wave loading gun, and a negative electrode output line is connected with a negative electrode line of the compression wave loading gun. The compression wave capacitor charger consists of a capacitor box and a control box. Wherein the capacitor boxes each contain a capacitor bank and electronic switches. A capacitor bank of the compression wave capacitor charger is formed by connecting 10 pulse capacitors in parallel, the rated voltage of each pulse capacitor is 1000V, and the capacitance value is 200 microfarads. The control box comprises a PLC and a control system thereof. The control system mainly comprises an analog control part, a digital control part and a digital display part. The analog control part can adopt TCA785 chip of SIEMENS company; the digital control part can be composed of Siemens S7-200 series and Siemens analog input and output expansion module EM 235. The charging voltage control is mainly realized by a PID control mode of the voltage loop and the current loop. The digital display section may be constituted by a text display TD200 of the series S7-200.
Because the three sets of compression stress wave generators in different axial directions are mutually independent, in order to enable the three sets of compression stress wave generators to simultaneously generate compression stress waves, a stress wave synchronizing device is needed to be adopted, the device generates a switching signal, electric energy storage and release devices in the three sets of compression stress wave generators are enabled to simultaneously discharge, and therefore the three sets of compression stress waves in different axial directions are simultaneously generated to load a sample. The stress wave synchronizer is simultaneously connected with the capacitor banks of the six compression stress wave generators through leads and used as a switching signal generator to replace an electronic switch of a compression wave capacitor charger. In an embodiment, the stress wave synchronizer may employ a digital delay generator of model DG645 from SRS corporation in the united states.
In the embodiment of the application, the power supplies adopt 380V industrial three-phase alternating current.
Referring to fig. 2 and 4, the sample 4 is a cube with chamfered edges, six faces of the cube are loading contact faces, the loading contact faces have chamfered edges therebetween, and the side length of the loading contact faces can be 10mm, that is, the loading contact faces of the sample and the cross section of the waveguide rod have the same area, so that the proximal ends of the six waveguide rods contact with the six loading contact faces to hold the sample. The compression stress wave generator of each set of compression devices simultaneously generates a compression stress wave that propagates from the distal end of the compression rod to the sample to simultaneously symmetrically load the sample at three axes.
In the process of loading the sample, strain signals generated by the compression rods are collected through the data collector, and therefore the internal stress of the sample is calculated according to the strain signals.
Referring to fig. 1, 3A to 3C and 4, to determine the axial position of the compression rods, an alignment jig 3 is used in the present application to align the axial position of six compression rods. As shown in fig. 3A, the calibration jig 3 is a cube having an internal space, and has openings 31 at the center positions of six faces of the cube, the area of the openings corresponding to the area of the cross section of the compression rod, that is, the compression rod can pass through the openings, and there is no significant gap between the compression rod and the openings, so that the axial position of the compression rod can be calibrated to make any two of the three sets of compression devices axially perpendicular to each other. In an embodiment, in order to facilitate the assembly of the fixed compression bar (hopkinson bar), the calibration jig may be made up of two identical parts, one of which is shown in perspective with reference to fig. 3B, and fig. 3C is a top view of fig. 3B. After the six compression rods are fixed in position and the sample is clamped, the two parts are connected through the bolts and the screw holes 32 to form the calibration fixture. The axial position of the compression rod is determined and calibrated by the calibration clamp, the compression rod can be accurately and rapidly installed, and the axial position of the compression rod can be always kept in the experimental process.
When the sample is clamped, the sample is positioned in the inner space of the calibration clamp, and the compression rod of the compression device is inserted into the calibration clamp through the opening to clamp the sample. The internal space of the calibration fixture is a cube, and the side length of the cube is more than 2 times of that of the sample.
Referring to fig. 5, a three-axis bidirectional compression loading method according to an embodiment of the present application includes the following steps:
step S502, three groups of compression devices are arranged according to a space rectangular coordinate system; wherein any two of the three sets of compression devices are mutually vertical in the axial direction; each group of compression devices respectively comprises a compression stress wave generator and a compression rod;
step S504, clamping a sample through the three groups of compression devices, wherein the sample is a cube with chamfered edges;
step S506, the compression stress wave generators of each group of compression devices simultaneously generate compression stress waves, and the compression stress waves are transmitted to the sample from the far ends of the compression rods so as to symmetrically load the sample on three axes simultaneously;
and step S508, collecting strain signals generated by the compression rods, and calculating the internal stress of the sample according to the strain signals.
Details of the above process are described in detail below in conjunction with fig. 6.
Step 1, setting a device.
The six compression stress wave generators 1 and the six compression rods 2 are divided into three groups, namely an X group, a Y group and a Z group (which respectively correspond to an X axis, a Y axis and a Z axis of a space rectangular coordinate system). Each set of which comprises two compressive stress wave generators 1 and two compression rods 2. In each group, the stress wave generator 1, the compression rod 2 and the stress wave generator 1 are sequentially arranged on an experiment table in a coaxial sequence, the compression rod 2 can only freely move in the axial direction, and each group can be a standard uniaxial bidirectional loading Hopkinson rod experiment device. The axes of the X group, the Y group and the Z group are mutually vertical.
In an embodiment, four compression rods 2 of X group and four compression rods 2 of Y group may be inserted into the calibration jig 3, the test sample 4 is placed into the calibration jig 3, and finally two compression rods 2 of Z group are inserted into the calibration jig 3, so as to ensure axial alignment between the three compression rods 2, and finally two parts of the calibration jig 3 are connected into one calibration jig 3 by bolts. Wherein the sample is a cubic sample with a chamfered edge. The end faces of the compression bars 2 in the X, Y, and Z groups are respectively bonded to the X, Y, and Z-direction surfaces of the sample 4.
And 2, pasting the strain gauge.
The adhered strain gauges 5 are divided into three groups, namely an X group of strain gauges 5, a Y group of strain gauges 5 and a Z group of strain gauges 5, which are respectively used for measuring strain signals of the X group, the Y group and the Z group of compression rods 2. Each group of strain gauges 5 comprises four strain gauges 5, parameters of the four strain gauges 5 are completely the same, two strain gauges 5 are symmetrically adhered to the surface of one compression rod 1/2 in the same group in length, the measurement direction of each strain gauge 5 is the same as the axial direction of the adhered rod, the other two strain gauges 5 are symmetrically adhered to the surface of the other compression rod 1/2 in the same group in length, and the measurement direction of each strain gauge 5 is the same as the axial direction of the adhered rod. The lead wires of the strain gauge 5 are connected into a Wheatstone bridge 6 by adopting a two-core shielded wire. Meanwhile, the output signal of the Wheatstone bridge 6 is connected to the input end of the data collector 7 by adopting a double-core shielding wire.
And 3, loading experiments and acquiring data.
And respectively charging the capacitor chargers of the X group of compression stress wave generators 1, the Y group of compression stress wave generators 1 and the Z group of compression stress wave generators 1, wherein the charging voltage is not higher than the rated voltage of each group of capacitor chargers. After the charging is completed, the time for generating the compression stress wave is set in the stress wave synchronizer 8. The stress wave synchronizer 8 simultaneously sends a switching signal to the X group of compressive stress wave generators 1, the Y group of compressive stress wave generators 1 and the Z group of compressive stress wave generators 1, and at the moment, the capacitor chargers of the X group of compressive stress wave generators 1, the Y group of compressive stress wave generators 1 and the Z group of compressive stress wave generators 1 simultaneously discharge at the time set by the stress wave synchronizer.
Taking an X group of experimental devices as an example, in an X group of compression stress wave generators 1, a capacitor charger discharges main coils of two compression loading guns at the same time, so that electromagnetic repulsion force is generated between a conical amplifier and the main coils, the electromagnetic repulsion force is expressed as compression stress waves in the conical amplifier, the stress waves are amplified by the conical amplifier to form compression incident waves and are transmitted into two compression rods 2, when the compression incident waves are transmitted to contact surfaces of the compression rods 2 and a sample 4, because of mismatching of wave impedances, a part of the compression incident waves are reflected, and compression reflected waves are formed in the compression rods 2; another portion is transmitted through the sample 4 into another compression rod 2 of the same set, forming a compressed transmitted wave. The shape and amplitude of the compressed reflected wave and the compressed transmitted wave are determined by the properties of the sample material. As the strain gauge 5 is connected with the Wheatstone bridge 6, a strain signal in the strain gauge 5 is converted into the change of the bridge arm voltage of the Wheatstone bridge 6, the data collector 7 is connected with the Wheatstone bridge 6 through a signal line, and the data collector 7 adopts a difference method for input to counteract the electromagnetic interference. The data collector 7 records and stores the change of the bridge arm voltage of the Wheatstone bridge 6. Wherein the strain gauge group 5 stuck on the compression rod A along the axis of the rod enables the incident wave signal V of the compression rod A to beXI1A reflected wave signal VXR1And the transmitted wave signal V of the compression bar BTR2Recording; the strain gauge group 5 adhered to the compression rod B along the axial line enables the incident wave signal V of the compression rod B to beXI2A reflected wave signal VXR2And the transmitted wave signal V of the compressed rod armorXT1Record (compression bars a, b are the two compression bars of the X set of compression devices). Then the voltage signal recorded by the data collector 7 is converted into a strain signal on the rod, and the specific formula is as follows:
ε＝2V/k/(U-V) (1)
wherein epsilon is a stress wave strain signal, U is a power supply voltage of the Wheatstone bridge 6, k is a strain gauge sensitivity coefficient, and V is a voltage value of the stress wave signal recorded by the data collector 7.
Compressing the incident wave signal V of the bar armor by the formula (1)i1Converted into incident wave strain signal epsiloni1A reflected wave signal Vr1Converted into a compressive reflected wave strain signal epsilonr1Transmitted wave signal Vt1Converted into a compressive transmitted wave strain signal epsilont1(ii) a Incident wave signal V of compression bar Bi2Converted into incident wave strain signal epsiloni2A reflected wave signal Vr2Converted into a compressive reflected wave strain signal epsilonr2Transmitted wave signal Vt2Converted into a compressive transmitted wave strain signal epsilont2. For a uniaxial two-way compression experimental device, a strain signal in a rod is processed by utilizing a one-dimensional elastic stress wave propagation theory, and the formula is as follows:
wherein,is the compressive strain rate, ε, of sample 4sIs the compressive strain, σ, of sample 4sCompressive stress of sample 4, C0Is the compression wave velocity, L, of the compression rod 2sIs the length of the gauge length of the sample 4, A is the cross-sectional area of the compression bar 2, AsIs the cross-sectional area of sample 4 and E is the young's modulus of the compression bar 2.
After the data processing is finished, with epsilonsIs X axis, sigmasPlotting the Y axis to obtain the stress-strain curve of the sample 4 in the X direction; with time t as the X axis, withThe time-strain rate change curve of the sample 4 in the X direction is obtained for the Y axis.
Similarly, according to the above process, the stress-strain curves and the time-strain rate change curves of the sample 4 in the Y direction and the Z direction can be obtained, and are not described again.
The operation steps of the method of the present invention correspond to the structural features of the device, and may be referred to one another, and are not described in detail.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (10)
1. A three-axis bidirectional compression loading method is characterized by comprising the following steps:
three groups of compression devices are arranged according to a space rectangular coordinate system; wherein any two of the three sets of compression devices are mutually vertical in the axial direction; each group of compression devices respectively comprises a compression stress wave generator and a compression rod;
clamping a sample by the three groups of compression devices, wherein the sample is a cube with a chamfered edge;
the compression stress wave generator of each group of compression devices simultaneously generates compression stress waves, and the compression stress waves are transmitted to the sample from the far end of the compression rod so as to simultaneously and symmetrically load the sample in three axes;
and acquiring strain signals generated by the compression rods, and calculating the internal stress of the sample according to the strain signals.
2. The method of claim 1, wherein each set of compression devices is coaxially arranged in the order of a compressive stress wave generator, a compression rod, a compressive stress wave generator; wherein the compression rod moves only in the axial direction.
3. The method of claim 1, further comprising:
providing a calibration jig for determining the axial position of the compression rod; the calibration clamp is a cube with an internal space, the centers of six faces of the cube are respectively provided with an opening, and the area of the opening is matched with the area of the cross section of the compression rod;
and placing the sample into the inner space of the calibration jig, and inserting a compression rod of a compression device into the calibration jig through the through hole to hold the sample.
4. The method of claim 3, wherein the internal space of the calibration jig is a cube having a side length that is more than 2 times a side length of the sample.
5. The method of claim 1, wherein the strain signal comprises: incident wave signal, reflected wave signal, transmitted wave signal.
6. A three-axis bi-directional compression loading device, comprising:
the three groups of compression devices are arranged according to a space rectangular coordinate system; wherein any two of the three sets of compression devices are mutually vertical in the axial direction; each group of compression devices respectively comprises a compression stress wave generator and a compression rod;
a sample, which is a cube with chamfered edges, and is clamped by the three groups of compression devices; the compression stress wave generator of each group of compression devices simultaneously generates compression stress waves, and the compression stress waves are transmitted to the sample from the far end of the compression rod so as to simultaneously and symmetrically load the sample in three axes;
and the data acquisition unit is used for acquiring strain signals generated by the compression rods so as to calculate the internal stress of the sample according to the strain signals.
7. The apparatus of claim 6, wherein each set of compression devices is coaxially arranged in the order of the compressive stress wave generator, the compression rod, the compressive stress wave generator; wherein the compression rod moves only in the axial direction.
8. The apparatus of claim 6, further comprising:
a calibration jig for determining an axial position of the compression rod; the calibration clamp is a cube with an internal space, the centers of six faces of the cube are respectively provided with an opening, and the area of the opening is matched with the area of the cross section of the compression rod; wherein the sample is placed in the inner space of the jig, and a compression rod of a compression device is inserted into the jig through the through hole to hold the sample.
9. The apparatus of claim 8, wherein the internal space of the calibration jig is a cube having a side length 2 times or more the side length of the sample.
10. The apparatus of claim 6, wherein the strain signal comprises: incident wave signal, reflected wave signal, transmitted wave signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811137535.8A CN109297812A (en) | 2018-09-28 | 2018-09-28 | Three axis biaxial compressive loading methods and its system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811137535.8A CN109297812A (en) | 2018-09-28 | 2018-09-28 | Three axis biaxial compressive loading methods and its system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109297812A true CN109297812A (en) | 2019-02-01 |
Family
ID=65164661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811137535.8A Pending CN109297812A (en) | 2018-09-28 | 2018-09-28 | Three axis biaxial compressive loading methods and its system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109297812A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110044683A (en) * | 2019-04-08 | 2019-07-23 | 三峡大学 | The device and method of rock bridge tension resistance creep between a kind of instrument connection using swelling agent |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10239229A (en) * | 1997-02-26 | 1998-09-11 | Sumitomo Metal Ind Ltd | High-pressure and high-speed three-axis testing apparatus and holding jig for object to be tested |
| CN104677760A (en) * | 2015-01-30 | 2015-06-03 | 西北工业大学 | Implementation method for equivalently loading incident wave in double-shaft split Hopkinson pressure bar and pull rod experiments |
| CN105928678A (en) * | 2016-04-18 | 2016-09-07 | 中国空间技术研究院 | CCD image sensor vibration and impact test fixture |
| CN205719826U (en) * | 2016-06-13 | 2016-11-23 | 中国科学技术大学 | A kind of rock Hopkinson impact loading experiment device based on true triaxial static load |
| CN107941615A (en) * | 2017-12-21 | 2018-04-20 | 四川德翔科创仪器有限公司 | A kind of three-axis tester and pilot system |
| CN108548942A (en) * | 2018-05-09 | 2018-09-18 | 西北工业大学 | Hopkinson pressure bar systems and method with true triaxial dynamic load and test function |
-
2018
- 2018-09-28 CN CN201811137535.8A patent/CN109297812A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10239229A (en) * | 1997-02-26 | 1998-09-11 | Sumitomo Metal Ind Ltd | High-pressure and high-speed three-axis testing apparatus and holding jig for object to be tested |
| CN104677760A (en) * | 2015-01-30 | 2015-06-03 | 西北工业大学 | Implementation method for equivalently loading incident wave in double-shaft split Hopkinson pressure bar and pull rod experiments |
| CN105928678A (en) * | 2016-04-18 | 2016-09-07 | 中国空间技术研究院 | CCD image sensor vibration and impact test fixture |
| CN205719826U (en) * | 2016-06-13 | 2016-11-23 | 中国科学技术大学 | A kind of rock Hopkinson impact loading experiment device based on true triaxial static load |
| CN107941615A (en) * | 2017-12-21 | 2018-04-20 | 四川德翔科创仪器有限公司 | A kind of three-axis tester and pilot system |
| CN108548942A (en) * | 2018-05-09 | 2018-09-18 | 西北工业大学 | Hopkinson pressure bar systems and method with true triaxial dynamic load and test function |
Non-Patent Citations (2)
| Title |
|---|
| 白盼: "三维霍普金森压杆试验装置调试与试验验证", 《中国优秀硕士学位论文全文数据库》 * |
| 聂海亮等: "单轴双向加载分离式霍普金森压杆的数据处理方法", 《爆炸与冲击》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110044683A (en) * | 2019-04-08 | 2019-07-23 | 三峡大学 | The device and method of rock bridge tension resistance creep between a kind of instrument connection using swelling agent |
| CN110044683B (en) * | 2019-04-08 | 2021-07-27 | 三峡大学 | Device and method for testing tensile and compressive creep of interbore rock bridge by using expanding agent |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108344648B (en) | Single-shaft bidirectional loading separation type Hopkinson pressure bar and pull bar device and experimental method | |
| JP6840390B2 (en) | Electromagnetic induction type Hopkinson tension / compression rod loading device and experimental method | |
| CN108519283A (en) | A kind of dynamic mechanics parameter of material acquisition device and method | |
| CN108519296A (en) | A kind of dynamic mechanics parameter of material acquisition device and method | |
| CN108344649B (en) | Dynamic biaxial tension loading device and experimental method | |
| CN108548942B (en) | Hopkinson pressure bar system with true triaxial dynamic loading and testing functions and method | |
| CN103926138B (en) | Based on Hopkinson strut and tie stress wave generator and the experimental technique of electromagnetic force | |
| CN102109436B (en) | Electromagnetic impact dynamic tensile test method and device | |
| CN100426001C (en) | Multi-field coupling measuring system | |
| CN104677760A (en) | Implementation method for equivalently loading incident wave in double-shaft split Hopkinson pressure bar and pull rod experiments | |
| CN111665152A (en) | Material dynamic compression circulating loading device and method thereof | |
| CN110542869A (en) | Weak magnetic field measuring device and method based on modal localization effect | |
| CN109297811A (en) | Double-shaft two-way compression-loaded devices and methods therefor | |
| CN111579404A (en) | Dynamic uniaxial bidirectional compression experimental method for brittle material | |
| CN104458081A (en) | Stress measurement primary stress separation method and device based on ultrasonic surface wave | |
| CN101887048A (en) | Barkhausen detection system and method under condition of high-speed operations | |
| CN115901501A (en) | Dynamic torsion-stretching/compressing synchronous combined loading device and loading method | |
| CN102788709A (en) | Automatic remainder detection device and method for spaceborne electronic equipment | |
| CN107817045B (en) | Magnetic coupling resonant frequency detection device and frequency detection method | |
| CN109297812A (en) | Three axis biaxial compressive loading methods and its system | |
| CN111830240B (en) | Loading control and data synchronous monitoring device of true triaxial multi-field coupling and power disturbance platform | |
| CN102033189A (en) | Method for measuring transformer product short circuit vibration displacement and deformation by utilizing laser sensor | |
| CN203519229U (en) | Quartz piezoelectric six-dimensional force detecting device | |
| CN111442892B (en) | Loading system and method based on electromagnetic Hopkinson bar technology | |
| CN111947564A (en) | Rock sample deformation measuring device, equipment and 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 |
Application publication date: 20190201 |
|
| RJ01 | Rejection of invention patent application after publication |