CN217786736U - Extensometer anti-slip testing device in high-temperature quasi-static loading test - Google Patents

Extensometer anti-slip testing device in high-temperature quasi-static loading test Download PDF

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CN217786736U
CN217786736U CN202221793914.4U CN202221793914U CN217786736U CN 217786736 U CN217786736 U CN 217786736U CN 202221793914 U CN202221793914 U CN 202221793914U CN 217786736 U CN217786736 U CN 217786736U
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clamping
extensometer
positioning hole
arc
sample piece
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李锦涛
王波
张程煜
索涛
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Northwestern Polytechnical University
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Northwestern Polytechnical University
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Abstract

The anti-slip testing device for the extensometer in the high-temperature quasi-static loading test comprises a sample piece, wherein two clamping pairs are arranged at a clamping end of the sample piece, each clamping pair comprises two clamping blocks, two screws and two nuts, each clamping block comprises an arc-shaped clamping surface and a fixing surface positioned on the back surface, the arc-shaped clamping surface faces and contacts the sample piece, the fixing surface is provided with two through holes, and the screws penetrate through the through holes between the clamping blocks and are screwed by the nuts so that the two clamping blocks clamp the sample piece through the arc-shaped clamping surfaces; the middle of the fixing surface of the clamping block is provided with a positioning hole, the clamping block, a screw and a nut are made of AlN, and the central axis of the positioning hole and the central axis of the through hole are in the same horizontal plane with the central axis of the arc-shaped clamping surface of the clamping block.

Description

Extensometer anti-slip testing device in high-temperature quasi-static loading test
Technical Field
The utility model relates to a fixing device, it is concrete relates to a extensometer anti-skidding testing arrangement among high temperature quasi-static loading test.
Background
At the present stage, the requirements on the use temperature, the strength and the rigidity of high-temperature resistant structural materials in the fields of aerospace, nuclear industry, metallurgy and the like are higher and higher, so that quasi-static mechanical performance tests need to be carried out on various high-temperature resistant materials in a high-temperature environment (higher than 800 ℃), and more accurate loaded deformation data can be obtained through a high-temperature extensometer, so that reliable material rigidity can be obtained. In the high-temperature mechanical property testing process, the high-temperature extensometer realizes point or line contact with the surface of a test piece through the ceramic extension rod, and axial pressure is applied to the extension rod. Therefore, the positioning is finished by certain friction force at the contact position, and the measurement of the deformation degree of the test piece is further realized.
However, the above-mentioned devices have found certain drawbacks, in particular: in the test loading process, for materials with higher hardness, the friction force of the contact position of the extension rod and the test piece is not enough to maintain the relative static state between the extension rod and the test piece, and the extension rod is easy to slip, so that the strain measurement fails.
At present, 3 common methods for applying axial pressure to an extension rod are available:
the first one is to bind the extensometer and the test piece together with asbestos rope or ceramic fiber, and to fix the extensometer by means of the tensile force of the rope. However, in a high temperature environment of 1300 ℃ or above, the asbestos cord and the ceramic fiber change color and are pulverized within a few minutes, sufficient pressure cannot be provided for the extension rod, and deformation measurement cannot be achieved.
The second high-temperature furnace mounting bracket is used for providing a certain pressure by virtue of the bracket to complete the fixation of the extensometer, but the method needs additional space for placing the bracket, is complex to operate and has higher cost.
The third kind has the trilateral edge of a knife structural style's that is U type distribution joint spare through the design, relies on the compaction contact of trilateral edge of a knife and measured material surface of the tight power in top of high temperature extensometer and the self gravity of joint spare realization, and then prevents the relative slip between ceramic joint and material surface through increasing contact area and area of contact. But this design need add the balancing weight and guarantee that the packing force of edge of a knife is enough, and the balancing weight needs extra space, and test piece and joint spare all take place thermal expansion under the high temperature environment simultaneously, and stress concentration is likely to appear on the edge of a knife, leads to ceramic edge of a knife because of stress too big and cracked, also is likely to joint spare inflation leads to the test piece pine to take off at the excessive speed, finally all can cause the strain measurement failure.
Therefore, when the high-hardness material high-temperature environment load test strain measurement is performed, the frequently-occurring extensometer extension rod slips to cause the failure phenomenon of the strain measurement, so that the self-clamping of the test piece at high temperature is realized, the load test strain measurement result of the high-hardness material at high temperature is more accurate and reliable, and the technical problem to be solved in the prior art is formed.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a extensometer testing arrangement that skids among high temperature quasi-static loading test realizes the self-holding of test piece under the high temperature for the high rigidity material is more accurate, reliable under high temperature environment load test strain measurement result, and on the other hand reduce cost enlarges strain measurement's temperature application scope on the one hand.
To achieve the purpose, the utility model adopts the following technical proposal:
the utility model provides a extensometer anti-skidding testing arrangement among high temperature quasi-static loading test which characterized in that includes:
the sample piece is provided with an upper clamping pair positioned at the upper part of the clamping end and a lower clamping pair positioned at the lower part of the clamping end at the clamping end of the sample piece;
each clamping pair comprises two clamping blocks, two screws and two nuts,
each clamping block comprises a circular arc-shaped clamping surface and a fixing surface located on the back surface, the circular arc-shaped clamping surface faces and contacts the sample piece, the fixing surface is provided with two through holes, and the screw penetrates through the through hole between the clamping block pairs and is screwed down by the nut, so that the two clamping blocks clamp the sample piece through the circular arc-shaped clamping surfaces.
Optionally, a positioning hole is formed in the middle of the fixing surface of the clamping block, and the positioning hole is used for inserting the extensometer to realize strain measurement of the sample.
Optionally, the positioning hole is shaped such that the positioning hole is in surface contact with the end of the extension rod of the extensometer inserted into the positioning hole.
Optionally, the positioning hole is a tapered hole.
Optionally, the clamping block, the screw and the nut are made of ceramic materials.
Optionally, the ceramic material is AlN.
Optionally, the positioning hole is located between the two through holes.
Optionally, the central axis of the positioning hole, the central axis of the through hole and the central axis of the circular arc-shaped clamping surface of the clamping block are on the same horizontal plane.
The utility model has the advantages of as follows:
(1) The utility model can completely arrange the sample and the anti-slip device in the high temperature vacuum environment, the test operation is convenient, and the cooling design is not needed to be considered;
(2) The utility model has the advantages that although the arc surface is in line contact with the test piece, the arc surface is less prone to stress concentration, so that the device is more reliable and durable;
(3) The shape of the middle positioning hole of the utility model needs to ensure that the middle positioning hole is in surface contact with the end of the extension rod, but not in point contact or line contact, so that the contact surface of the extension rod and the clamping block is close to the whole end surface of the extension rod, and the contact area of the clamping block and the test piece is much larger than that of the three common methods at present, thereby allowing larger pressure to be applied and ensuring the anti-slip requirement;
(4) The utility model ensures that the center axes of the positioning holes, the center axes of the through holes and the center axes of the cambered surfaces of the clamping blocks are in the same horizontal plane, so that the cambered surfaces of the clamping blocks tightly attached to the test piece ensure that the length of the scale distance measured by the extensometer is clear and measurable, and the test efficiency is high;
(5) The utility model discloses an adopt high temperature resistant and the little material preparation of coefficient of thermal expansion whole anti-skidding device, realized self-fastening centre gripping under the high temperature, need not exert external force again, simple structure is reliable.
Drawings
FIG. 1 is an exterior view of a sample piece according to a particular embodiment;
FIG. 2 is an external view of an extensometer anti-slip testing device in a high temperature quasi-static loading test according to an embodiment;
FIG. 3 is an exploded view of an extensometer anti-slip test device in a high temperature quasi-static loading test according to a specific embodiment;
FIG. 4 is a front view of an extensometer anti-slip testing device in a high temperature quasi-static loading test according to a particular embodiment;
FIG. 5 is a cross-sectional view of an extensometer anti-slip test device during a high temperature quasi-static loading test according to a particular embodiment;
FIG. 6 is an exploded view of a clamp block of an extensometer anti-slip testing device in a high temperature quasi-static loading test according to an exemplary embodiment;
FIG. 7 is a front view of a clamp block of the extensometer anti-slip test device during a high temperature quasi-static loading test according to a particular embodiment;
FIG. 8 is a side cross-sectional view of a clamp block of a extensometer anti-slip testing device in a high temperature quasi-static loading test, according to a particular embodiment.
The technical characteristics respectively designated by the reference numerals in the figures are as follows:
1. a sample piece; 2. a screw; 3. a nut; 4. a clamping block; 5. positioning holes; 6. and a through hole.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
In the high-temperature environment test, the mechanical properties of the metal material and the ceramic matrix composite are mainly tested, so that reference is made to part 2 of GB/T228.2-2015 tensile test of metal materials: high temperature test method and American ceramic matrix composite high temperature tensile property test method (Standard No. ASTM C1275-15, domestic related test method and standard vacancy), the design test sample is shown in figure 1.
Wherein, the two ends of the sample piece are clamping ends, the round holes at the two ends are positioning holes, the middle part is a testing section, and the thickness is generally 2-6mm.
Referring to fig. 2 to 6, the anti-slip testing device for the extensometer in the high-temperature quasi-static loading test comprises:
a sample member 1 having an upper holding pair located at an upper portion of a holding end and a lower holding pair located at a lower portion of the holding end at a holding end of the sample member 1;
each clamping pair comprises two clamping blocks 4, two screws 2 and two nuts 3,
each clamping block 4 comprises a circular arc-shaped clamping surface and a fixing surface positioned on the back surface, the circular arc-shaped clamping surface faces and contacts the sample piece 1, the fixing surface is provided with two through holes 6, the screw 2 penetrates through the through holes 6 between the clamping block pairs and is screwed by the nut 3, and therefore the two clamping blocks clamp the sample piece through the circular arc-shaped clamping surfaces.
In one embodiment, the clamping pair in the anti-slip test device is made of a ceramic material (e.g., alN), so that the sample and the clamping pair can be placed in a high temperature environment (800-2200 ℃).
Furthermore, the clamping halving is divided into an upper part and a lower part, the two parts have the same structure, and are both prepared by adopting ceramic materials which are high temperature resistant and have thermal expansion coefficients smaller than that of the test piece, in particular, for most metals and SiC/SiC composite materials, alN is an ideal device material, and the bolt 2 passes through the through hole 6 between the clamping block pair and is screwed by the nut 3 to realize the clamping of the test piece.
Namely, the clamping block 4, the screw 2 and the nut 3 are all made of high-temperature resistant materials (such as AlN) with small thermal expansion coefficients, and are matched with the clamping block to clamp the gauge length section of the sample; through holes 6 between the clamping block pairs are coaxial through holes through screws.
Realize the centre gripping to the test piece under the normal temperature through screwing up the nut, under high temperature, the test piece is heated expanding, and the device that prevents skidding is less because of coefficient of thermal expansion to realize self-fastening under the high temperature, prevent to take place the relative slip of sample and clamp splice under the loading effect.
Furthermore, a positioning hole 5 is arranged in the middle of the fixing surface of the clamping block 4, and the positioning hole 5 is used for inserting a extensometer to realize strain measurement on a sample.
Furthermore, the shape of the positioning hole 5 is designed so that the positioning hole 5 is in surface contact with the end of the extension rod of the extensometer, rather than in point contact or line contact. The reason that the known extensometer extension rod easily skidded on the test piece lies in that the extension rod is point contact or line contact with the test piece, and area of contact is less, because of the material strength restriction, the requirement of not skidding is hardly satisfied to pressure and frictional force along the pole that provides, and the utility model discloses well extension rod is close the whole terminal surface of extension rod with the contact surface of locating hole, and contact area is greatly far greater in clamp splice and the three kinds of methods of test piece area of contact size also than the aforementioned, so allow to exert bigger pressure, guarantee the requirement of preventing skidding.
In one embodiment, the tip of the extension rod is conical, and the positioning hole is conical. The extensometer cannot slip due to being inserted into the tapered hole, so that the strain of the test piece can be accurately measured by the extensometer at high temperature.
However, the utility model is not limited to this, and the extension rod of other end faces such as wedge, spherical surface, etc. can be provided.
Further, referring to fig. 7-8, the positioning hole is located between two through holes, and the central axis of the positioning hole 5, the central axis of the through hole 6 and the central axis of the circular arc-shaped clamping surface of the clamping block 4 are in the same horizontal plane, so that the clamping block is tightly attached to the arc surface of the sample piece, and the length of the gauge length measured by the extensometer is clearly measurable.
The utility model discloses a prevent that testing arrangement skids carries out the high temperature test through following mode:
(1) A pair of ceramic clamping blocks are respectively arranged above and below the sample piece and clamped at the gauge length section of the sample piece;
(2) The positions of two positioning holes of the ceramic clamping block are adjusted by comparing the length of the gauge length of the high-temperature extensometer;
(3) Fixing the clamping blocks by using screws and nuts after the positions of the clamping blocks are determined;
(4) And then the extension rod of the high-temperature extensometer can be inserted into the positioning hole to start the test.
The utility model has the advantages of as follows:
(1) The utility model can completely arrange the sample and the anti-slip device in a high temperature vacuum environment, the test operation is convenient, and the cooling design is not needed to be considered;
(2) The utility model has the advantages that although the arc surface is in line contact with the test piece, the arc surface is less prone to stress concentration, so that the device is more reliable and durable;
(3) The shape of the middle positioning hole of the utility model needs to ensure that the middle positioning hole is in surface contact with the end of the extension rod, but not in point contact or line contact, so that the contact surface of the extension rod and the clamping block is close to the whole end surface of the extension rod, and the contact area of the clamping block and the test piece is much larger than that of the three common methods at present, thereby allowing the application of larger pressure and ensuring the anti-slip requirement;
(4) The utility model ensures that the center axes of the positioning holes, the center axes of the through holes and the center axes of the cambered surfaces of the clamping blocks are in the same horizontal plane, so that the cambered surfaces of the clamping blocks tightly attached to the test piece ensure that the length of the scale distance measured by the extensometer is clear and measurable, and the test efficiency is high;
(5) The utility model discloses an adopt high temperature resistant and the little material preparation of coefficient of thermal expansion whole anti-skidding device, realized self-fastening centre gripping under the high temperature, need not exert external force again, simple structure is reliable.
The above description is for the purpose of describing the invention in more detail with reference to specific preferred embodiments, and it is not to be construed that the embodiments of the invention are limited thereto, and it will be apparent to those skilled in the art that the invention can be embodied in many different forms without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (8)

1. The utility model provides a extensometer testing arrangement that skids among high temperature quasi-static loading test which characterized in that includes:
the sample piece is provided with an upper clamping pair positioned at the upper part of the clamping end and a lower clamping pair positioned at the lower part of the clamping end at the clamping end of the sample piece;
each clamping pair comprises two clamping blocks, two screws and two nuts,
each clamping block comprises an arc-shaped clamping surface and a fixing surface positioned on the back surface, the arc-shaped clamping surface faces and contacts the sample piece, the fixing surface is provided with two through holes, and the screw penetrates through the through hole between the clamping block pairs and is screwed by the nut, so that the two clamping blocks clamp the sample piece through the arc-shaped clamping surfaces.
2. The anti-skid test device according to claim 1,
and a positioning hole is formed in the middle of the fixing surface of the clamping block and used for inserting a extensometer to realize strain measurement of a sample.
3. The anti-skid test device according to claim 2,
the positioning hole is shaped so that the positioning hole is in surface contact with the end of the extension rod of the extensometer inserted into the positioning hole.
4. The anti-skid test device according to claim 3,
the positioning hole is a conical hole.
5. The anti-skid test device according to claim 1,
the clamping blocks, the screws and the nuts are made of ceramic materials.
6. The anti-skid test device according to claim 5,
the ceramic material is AlN.
7. The anti-skid test device according to claim 2,
the positioning hole is positioned between the two through holes.
8. The anti-skid test device according to claim 7,
the central axis of the positioning hole, the central axis of the through hole and the central axis of the circular arc-shaped clamping surface of the clamping block are on the same horizontal plane.
CN202221793914.4U 2022-07-12 2022-07-12 Extensometer anti-slip testing device in high-temperature quasi-static loading test Active CN217786736U (en)

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Application Number Priority Date Filing Date Title
CN202221793914.4U CN217786736U (en) 2022-07-12 2022-07-12 Extensometer anti-slip testing device in high-temperature quasi-static loading test

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CN217786736U true CN217786736U (en) 2022-11-11

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116380653A (en) * 2023-03-23 2023-07-04 鞍钢股份有限公司 Gauge length positioning device and method for biaxial stretching sample
CN117168970A (en) * 2023-11-02 2023-12-05 天津航天瑞莱科技有限公司 Extensometer clamping device based on filling hole compression performance test

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116380653A (en) * 2023-03-23 2023-07-04 鞍钢股份有限公司 Gauge length positioning device and method for biaxial stretching sample
CN117168970A (en) * 2023-11-02 2023-12-05 天津航天瑞莱科技有限公司 Extensometer clamping device based on filling hole compression performance test
CN117168970B (en) * 2023-11-02 2023-12-29 天津航天瑞莱科技有限公司 Extensometer clamping device based on filling hole compression performance test

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