CN216926434U - Dynamic indentation experimental device capable of realizing dynamic compression - Google Patents
Dynamic indentation experimental device capable of realizing dynamic compression Download PDFInfo
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- CN216926434U CN216926434U CN202122792278.5U CN202122792278U CN216926434U CN 216926434 U CN216926434 U CN 216926434U CN 202122792278 U CN202122792278 U CN 202122792278U CN 216926434 U CN216926434 U CN 216926434U
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- 238000007373 indentation Methods 0.000 title claims abstract description 52
- 230000006835 compression Effects 0.000 title claims abstract description 19
- 238000007906 compression Methods 0.000 title claims abstract description 19
- 238000012360 testing method Methods 0.000 claims abstract description 33
- 230000005540 biological transmission Effects 0.000 claims abstract description 28
- 238000012669 compression test Methods 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 11
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 6
- 239000010959 steel Substances 0.000 claims abstract description 6
- 229920001875 Ebonite Polymers 0.000 claims abstract description 3
- 239000000956 alloy Substances 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 230000000694 effects Effects 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 3
- 238000007542 hardness measurement Methods 0.000 claims description 2
- 230000000452 restraining effect Effects 0.000 claims description 2
- 239000011888 foil Substances 0.000 claims 1
- 238000002474 experimental method Methods 0.000 abstract description 19
- 230000006911 nucleation Effects 0.000 abstract description 2
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- 239000000463 material Substances 0.000 description 6
- 230000003287 optical effect Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
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Abstract
The utility model discloses a dynamic indentation experimental device capable of realizing dynamic compression, which is characterized by comprising a striking rod, a light trigger speed measuring device, a buffer block and a linear variable differential sensor, wherein strain gauges are respectively arranged between an incident rod and a transmission rod, the strain gauges are electrically connected with a super dynamic strain gauge, the rear end of the transmission rod is provided with a compression test piece, a pressure head is arranged at the rear end of the compression test piece through a positioning groove, an indentation test piece is arranged behind the pressure head, the front end of the incident rod is provided with a steel momentum trap assembly of flange-sleeve-rigid mass, a guide constraint device ensures that the incident rod, a workpiece and the transmission rod are positioned on the same axis, the front end of the incident rod is provided with a speed measuring device, the rear end of the transmission rod is provided with a force sensor, hard rubber positioning rings with different thicknesses are adopted to position the test piece, the prestress is avoided, and simultaneously, the cushion function is realized when the test piece is crushed, and the rod piece is protected; the method has the advantages that the stress-strain curve under the same impact load can be obtained while the dynamic indentation experiment is carried out, and the crack nucleation and propagation mechanism of the test piece can be analyzed.
Description
Technical Field
The utility model relates to the field of measurement of dynamic mechanical properties of hard and brittle materials, in particular to a dynamic indentation experimental device for hard and brittle materials.
Background
At present, the existing indentation technology mainly focuses on static indentation experiments, such as common nano indentation experiments; the development of the dynamic indentation experiment technology is not mature; when a dynamic indentation experiment is carried out, a stress-strain curve under the same variable load is difficult to obtain, and the analysis of the nucleation and expansion mechanism of the crack of the test piece is not facilitated; pulses cannot be controlled in experiments, and single indentation is difficult to realize; in the indentation experiment process, the relative position of the test piece and the experiment device is changed, so that the experiment precision and the experiment equipment are influenced; the hardness of the hard and brittle material is high, the impact speed is high under the dynamic loading condition, and the service life of the experimental device can be shortened by high-speed impact in the experimental process.
Disclosure of Invention
The purpose of the utility model is: in order to overcome the defects of the prior art, the utility model provides the experimental device which has high measurement precision and simple structure and can simultaneously realize dynamic compression and dynamic indentation.
In order to realize the purpose of the utility model, the following technical scheme is adopted for realizing the purpose: a dynamic indentation experimental device capable of realizing dynamic compression comprises: the device comprises an impact rod, an optical trigger speed measuring device, a buffer block and a linear variable differential sensor, wherein strain gauges are respectively installed between the incident rod and a transmission rod, a compression test piece is installed at the front end of the transmission rod, a pressure head is installed at the rear end of the compression test piece through a positioning groove, and an indentation test piece is installed at the rear end of the pressure head.
And the incident rod dynamically compresses the compression test piece while dynamically indenting the indentation test piece under the impact action of the impact rod.
The guide constraint device is a hollow cylinder with the inner diameter coaxial with the transmission rod and the incident rod, an opening is formed right above the guide constraint device, the guide constraint device is made of hard alloy, and the incident rod, the compression test piece, the transmission rod and the indentation test piece are guaranteed to keep the same axis in the experiment process.
The front end of the incident rod is provided with a 'momentum trap' steel component of 'flange-sleeve-rigid mass', the material of the steel component is hard alloy, reflected pulses are absorbed, single indentation experiment is realized, and secondary or even multiple indentations are avoided from influencing the experiment result.
The linear variable differential sensor is directly connected with the transmission rod through the baffle.
The distance between the center and the edge of the indentation test piece is at least 2.5 times of the indentation diagonal line, so that the indentation hardness measurement is not influenced by the boundary effect, the thickness is 1.5 times of the indentation diagonal line, complete radial/middle cracks are contained, and complete fracture and crack information loss are avoided.
The diameters of the compression test piece and the indentation test piece are both smaller than the inner diameter of the guide constraint device and are fixed through a positioning ring.
The position circle adopts the hard rubber, and multiple thickness is used for matcing not unidimensional test piece, avoids producing the prestressing force when fixing a position the test piece, plays the blotter effect when the test piece collapses to be broken up simultaneously, protects incident pole and transmission pole.
Preferably, the pressure head is installed in a positioning hole mode, the pressure head rod is made of hard alloy, and a surface contact method is adopted, so that the installation accuracy is ensured, and meanwhile, the wave impedance matching condition rho is metsCsAs＝ρ0C0A0Where ρ issDensity of the piece under test, CsIs the wave velocity of one-dimensional stress wave of a tested piece, AsIs the cross-sectional area of the test piece, p0Density of incident and transmission rods, C0Is the wave velocity of one-dimensional stress wave of incident rod and transmission rod, A0The incident and transmission rod cross-sectional areas.
Compared with the prior art, the utility model has the beneficial effects that: the experiment device is used for carrying out dynamic indentation experiments on the hard and brittle materials and simultaneously carrying out dynamic compression experiments on the test piece, so that the problem that the mechanical property and the stress-strain curve under the condition of the same variable load cannot be accurately obtained in the dynamic indentation experiments is solved; the problem of mismatching of wave impedance of the pressure head and the incident rod due to large difference of cross section areas of the incident rod and the pressure head is solved; the problem of a plurality of indentations generated in the experimental process is avoided by adopting a steel ' flange-sleeve-rigid mass ' momentum trap ' component; the problem that the relative positions of a pressure head, a tested piece and the like are changed due to the fact that sloshing is generated in the impact process is avoided; the problems of overlarge impact load and impact damage of the rod piece are avoided.
Drawings
Fig. 1 illustrates the structural principle of the present invention.
Figure 2 illustrates an assembly view of the guiding and restraining device.
Figure 3 illustrates an exploded view of the directional restraint device.
1: a striker bar; 2: a light-triggered speed measuring device; 3: a flange; 4: a sleeve; 5: a rigid mass; 6: a momentum trap; 7: an incident rod; 8: a strain gauge; 9: compressing the test piece; 10: a guide restraint device; 11: a transmission rod; 12; a baffle plate; 13: a pressure head; 14: indenting the test piece; 15: a force sensor; 16: a buffer block; 17: a linear variable differential sensor; 18: and (6) positioning rings.
Detailed Description
The key points of the utility model are as follows: the impact rod 1 can be ejected at a certain speed under the action of the air gun, the speed of the impact rod 1 can be controlled by controlling the pressure of the air gun, and the initial speed of the impact rod is measured and recorded by the optical trigger speed measuring device 2. When the striker rod 1 strikes the flange 3, a compression pulse is simultaneously generated in the sleeve 4 and the incident rod 7. Wherein the compression pulses (C) in the sleeve 4sleeve) When reaching the rigid mass 5, it will be reflected back to the flange 3 in the form of a stretching pulse, and when reaching the end of the flange 3, it will have a stretching pulse (T)sleeve) Loaded into the entrance bar 7. Compressed pulses (C) in the incident rod 7impact) While the incident rod 7 is made to impact the compression test piece 9, the indenter 13 impresses the indentation test piece 14, and then the tension pulse (T) is formed by reflectionimpact) Which is captured by the momentum trap assembly 6 when it reaches the end of the flange 3, and which is not sensed by the strain gauge in subsequent readings. Therefore, the strain gauge 8 is installed at the center of the incident rod 7 and the transmission rod 11, and the compression pulse C is recordedimpactFollowed by a stretching pulse TsleeveBoth of which move toward the transmission rod 11. Initial stretching pulse (T)sleeve) Reaching the indenter will cause the indenter 13 to separate from the indentation specimen 14, followed by a compression pulse (C)sleeve) Is reflected back to the flange 3 end and then pulsed with a tension pulse (T)sleeve) Is reflected back to the end of the transmission rod 11. This process will be repeated several times, causing the indenter to retract and move away from the specimen. Thus, by properly designing the momentum trap 6, it is ensured that only one compression pulse reaches the end of the indenter, allowing dynamic indentation tests to be performed at high strain rates.
The duration of the input pulse can be varied by selecting different lengths of the striker rod 1 and the incident load can be achieved by varying the head of the air gun. The linear variable differential sensor 17 is directly connected with the transmission rod 11 through the baffle plate 12, and an experimental indentation depth time curve is obtained.
The optical trigger speed measuring device 2 is fixedly installed between the impact rod 1 and the incident rod 7, the optical trigger speed measuring device comprises a trigger timer, two laser tubes arranged side by side and two photosensitive tubes corresponding to the laser tubes vertically, the photosensitive tubes are located below the laser tubes, the photosensitive tubes are electrically connected with the trigger timer, and the initial speed of the impact rod 1 can be obtained.
A force sensor 15 is arranged between the indentation test piece 14 and the buffer block 16, and the force in the experiment is measured in situ through the force sensor 15.
Through the process, a stress-strain curve in a dynamic indentation experiment can be accurately obtained, comparison analysis with mechanical data under a quasi-static state is facilitated, and dynamic damage characteristic response of the material under a high strain rate is deeply researched.
Claims (8)
1. A dynamic indentation experimental device capable of realizing dynamic compression comprises: striking pole (1), light trigger speed sensor (2), buffer block (16), linear variable differential sensor (17), install foil gage (8) respectively in the middle of incident pole (7) and transmission pole (11), pass through constant head tank installation pressure head (13) in transmission pole (11) front end installation compression test piece (9) rear end, install indentation test piece (14), its characterized in that at the pressure head rear: the front end of an incidence rod (7) is provided with a momentum trap component (6) consisting of a flange (3), a sleeve (4) and a rigid mass (5), the rear end of a transmission rod is provided with a pressure head (13) through a positioning hole, the incidence rod (7), a compression test piece (9), the transmission rod (11) and an indentation test piece (14) are ensured to keep the same axis in the experimental process through a guide constraint device (10), a linear variable differential sensor (17) is directly connected with the transmission rod (11), the front end of the incidence rod is provided with a light trigger speed measuring device (2), and a force sensor (15) is arranged between the transmission rod (11) and a buffer block (16).
2. The dynamic indentation experimental device capable of realizing dynamic compression as claimed in claim 1, wherein the incident rod (7) dynamically compresses the compression test piece (9) while dynamically indenting the indentation test piece (14) under the impact action of the impact rod (1).
3. The dynamic indentation experimental device capable of realizing dynamic compression as claimed in claim 1, wherein the guiding and restraining device (10) is a hollow cylinder with an inner diameter coaxial with the transmission rod (11) and the incidence rod (7), and is opened right above the hollow cylinder, and is made of hard alloy, so as to ensure that the incidence rod (7), the compression test piece (9), the transmission rod (11) and the indentation test piece (14) keep the same axis in the experimental process.
4. The dynamic indentation experimental device capable of realizing dynamic compression as claimed in claim 1, wherein the front end of the incident rod (7) is provided with a momentum trap steel component (6) of flange (3) -sleeve (4) -rigid mass (5), and the momentum trap steel component is made of hard alloy to prevent multiple indentations.
5. A dynamic indentation testing device capable of dynamic compression as claimed in claim 1, characterized in that the linear variable differential transducer (17) is directly connected to the transmission rod (11) through the baffle (12).
6. The dynamic indentation experimental apparatus capable of realizing dynamic compression as claimed in claim 1, wherein the distance between the center and the edge of the indentation test piece (14) is at least 2.5 times of the indentation diagonal line, so as to ensure that the boundary effect does not influence the indentation hardness measurement, and the thickness is 1.5 times of the indentation diagonal line, so as to ensure that complete radial/middle cracks are contained, and complete fracture and crack information loss are avoided.
7. The dynamic indentation test device capable of realizing dynamic compression as claimed in claim 1, wherein the compression test piece (9) and the indentation test piece (14) are smaller in diameter than the inner diameter of the guide and constraint device (10) and are fixed through the positioning ring (18).
8. The dynamic indentation experimental device capable of realizing dynamic compression as claimed in claim 1, wherein the positioning ring (18) is made of hard rubber, and multiple thicknesses are used for matching test pieces with different sizes, so as to avoid prestress while positioning the test pieces, and simultaneously play a role of cushion when the test pieces are broken up, thereby protecting the incident rod (7) and the transmission rod (11).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122792278.5U CN216926434U (en) | 2021-11-16 | 2021-11-16 | Dynamic indentation experimental device capable of realizing dynamic compression |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122792278.5U CN216926434U (en) | 2021-11-16 | 2021-11-16 | Dynamic indentation experimental device capable of realizing dynamic compression |
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| Publication Number | Publication Date |
|---|---|
| CN216926434U true CN216926434U (en) | 2022-07-08 |
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| CN202122792278.5U Expired - Fee Related CN216926434U (en) | 2021-11-16 | 2021-11-16 | Dynamic indentation experimental device capable of realizing dynamic compression |
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| Country | Link |
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| CN (1) | CN216926434U (en) |
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2021
- 2021-11-16 CN CN202122792278.5U patent/CN216926434U/en not_active Expired - Fee Related
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