Uniaxial tensile mechanical property test fixture for brittle material

Abstract

The invention relates to a fragile material uniaxial tensile mechanical property test fixture which comprises clamping structures matched at two ends of a sample, the whole sample is a block, two sides of a clamping end of the sample are inclined planes, each clamping structure comprises a clamping main body, a clamping groove for the clamping end of the sample to enter is formed in the clamping main body, and the clamping grooves are matched with the clamping structures. The middle of the clamping groove is in a vertically-through cylinder shape, the clamping end is located at the cylindrical position of the clamping groove and clamped through two arc-shaped wedge blocks inserted into the cylindrical position of the clamping groove, the inclined face of the clamping end is attached to the arc-shaped wedge blocks, and the arc-shaped parts of the arc-shaped wedge blocks are attached to the groove wall of the clamping groove. The conical design that the sample clamping end is free of threads or pin hole machining is adopted, the clamp lining is matched with the semicircular clamping wedge block of the sample conical structure, and in the stretching process, the arc-shaped wedge block can adjust the axis of the sample at any time and lock the sample according to changes of the sample, loading and the like in the sample clamping process; and high-precision coaxiality in the tensile mechanical property testing process of the fragile material is realized.

Description

Technical Field

[0001] The present invention relates to the field of testing and analysis of the mechanical properties of brittle materials, especially the uniaxial tensile mechanical properties such as tensile, creep, and tensile-tensile fatigue, and particularly relates to a fixture for testing the uniaxial tensile mechanical properties of brittle materials. Background Art

[0002] Mechanical property testing is an important means to evaluate the behavior of materials under stress, and is widely used in the fields of materials science, engineering technology, and product quality control. In addition to the classic mechanical property tests of materials, such as tensile property, bending property, shear property, fatigue property, etc., there are also various testing methods such as torsion test, creep test, stress relaxation test, etc. These testing methods each have their specific application scenarios and purposes. For example, the torsion test is used to evaluate the torsional strength and torsional toughness of materials; the creep test is used to evaluate the deformation behavior of materials under high temperature and constant stress; and the stress relaxation test is used to evaluate the relationship between stress and time of materials under the condition of maintaining the initial deformation or displacement constant.

[0003] Generally, in conventional uniaxial tensile mechanical property tests such as tensile, tensile creep, and tensile-tensile fatigue, most specimens are connected to the pull rod of the mechanical loading testing machine through a threaded or hanging connection structure. Since there are requirements for coaxiality during the process of such mechanical property tests, the processing quality of the test specimens needs to be very high. For brittle materials such as ceramics, metallic glasses, and ceramic fibers, due to the high brittleness of the test specimens, even a slight deviation in coaxiality during the uniaxial tensile mechanical property test will cause the risk of non-axial fracture of the materials, and the requirement for coaxiality during the performance test process is higher. However, the processing of brittle materials is very difficult, and some cannot be processed at all. Therefore, it is impossible to use the conventional threaded or hanging connection structure to connect with the pull rod of the mechanical loading testing machine, resulting in difficulties in carrying out uniaxial tensile mechanical property tests. Summary of the Invention

[0004] The purpose of the present invention is to provide a fixture for testing the uniaxial tensile mechanical properties of brittle materials, which adopts a conical design without threaded or pinhole processing at the specimen clamping end, and the inner lining of the fixture is matched with a semi-circular clamping wedge block of the specimen conical structure. During the tensile process, the semi-circular wedge block can adjust the specimen axis at any time according to the changes of the specimen, loading, etc. and lock the specimen during the specimen clamping process, so as to achieve high-precision coaxiality during the tensile mechanical property test of brittle materials.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A uniaxial tensile mechanical property testing fixture for brittle materials, including a clamping structure that fits with both ends of the specimen. The specimen is a block as a whole, and both sides of the clamping end of the specimen are inclined planes. The clamping structure includes a clamping body, and a clamping groove for the clamping end of the specimen to enter is opened on the clamping body. The middle part of the clamping groove is a cylindrical shape that penetrates up and down. The clamping end is located at the cylindrical part of the clamping groove and is clamped tightly by two arc-shaped wedges inserted into the cylindrical part of the clamping groove. The inclined plane of the clamping end fits with the arc-shaped wedges, and the arc-shaped part of the arc-shaped wedges fits with the groove wall of the clamping groove.

[0006] Preferably, the specimen includes a gauge section in the middle, two clamping ends, and a transition section between the gauge section and the clamping ends. The transitions between the gauge section, the transition section, and the clamping ends are all smooth arcs.

[0007] Preferably, a threaded connection column is fixedly connected to the outer side of the clamping body away from the specimen, and the center of the threaded connection column is on the same straight line as the center of the specimen.

[0008] Preferably, positioning blocks that penetrate into the clamping groove and position and press the upper side or the lower side of the clamping end are provided on both the upper side and the lower side of the clamping body. The positioning blocks are locked on the clamping body by locking bolts 19.

[0009] Preferably, a lower block is installed on the lower part of the clamping body through a locking bolt, the lower positioning block is fixed on the lower block, and not less than two threaded holes are opened in the lower part of the arc-shaped wedge. The lower block is matched with the threaded holes in the lower part of the arc-shaped wedge through wedge clamping bolts.

[0010] Preferably, the upper parts of the two arc-shaped wedges form an integral structure through a connecting block, and the connecting block does not contact the clamping end of the specimen.

[0011] Preferably, water cooling cavities are opened on both sides of the clamping body, and the two water cooling cavities are communicated through a water cooling connection channel opened inside the clamping body. The water cooling cavities are matched with water cooling covers, and a water cooling sealing ring is provided at the edge of the water cooling cover. A water cooling joint communicated with the water cooling cavity is provided on the water cooling cover.

[0012] Preferably, the connection line of the two water cooling joints passes through the cylinder formed by the arc-shaped wedges, and the water cooling joints are in threaded fit with the water cooling covers. An installation bolt is fixedly connected inside the water cooling joints. A water cooling hole communicated with the inner cavity of the water cooling joint is opened outside the installation bolt. A communication hole is opened on a part of the side surface of the water cooling hole inside the water cooling cavity. The threaded end of the installation bolt passes through the clamping body and enters the threaded hole opened on the side surface of the arc-shaped wedge.

[0013] Preferably, a sealing block is sleeved on the installation bolt. After the installation of the installation bolt is completed, the sealing block fits tightly against the inner side of the water cooling cavity and generates pressure.

[0014] The technical effects of the present invention are as follows: 1. A conical design with no threaded or pin hole machining at the specimen clamping end is adopted, and the fixture lining is matched with a semi-circular clamping wedge for the conical structure of the specimen. During the stretching process, the semi-circular wedge can adjust the specimen axis at any time according to changes in the specimen, loading, etc. during the specimen clamping process and lock the specimen, achieving high-precision coaxiality during the tensile mechanical property test of brittle materials.

[0015] 2. The fixture is designed with a water-cooled part, which can realize the cooling of the fixture during the high-temperature tensile mechanical property tests such as high-temperature creep, high-temperature tension, and high-temperature fatigue, protecting the fixture and test safety.

[0016] 3. A positioning stop block is designed to protect the specimen, fixture from damage or test accidents caused by improper operation during the test. Brief Description of the Drawings

[0017] Figure 1 It is a three-dimensional schematic diagram of a uniaxial tensile mechanical property test fixture for brittle materials.

[0018] Figure 2 It is a three-dimensional schematic diagram of the specimen.

[0019] Figure 3 It is a cross-sectional view of a uniaxial tensile mechanical property test fixture for brittle materials.

[0020] Figure 4 It is a three-dimensional schematic diagram of the clamping structure.

[0021] Figure 5 It is a three-dimensional schematic diagram of the specimen, arc-shaped wedge, and positioning stop block.

[0022] Figure 6 It is a three-dimensional schematic diagram of the clamping structure after removing the water-cooling cover plate.

[0023] Figure 7 It is a three-dimensional schematic diagram of the clamping structure of Example 2.

[0024] Figure 8 It is a three-dimensional schematic diagram of the clamping structure of Example 3.

[0025] Figure 9 It is a three-dimensional schematic diagram of the clamping structure of Example 4.

[0026] Figure 10 It is a cross-sectional view of the clamping structure of Example 4.

[0027] The text markings shown in the figure are as follows: 1. Specimen; 2. Clamping structure; 3. Threaded connection column; 4. Gauge section; 5. Transition section; 6. Clamping end; 11. Clamping body; 12. Clamping groove; 13. Arc-shaped wedge block; 14. Water-cooling cavity; 15. Water-cooling joint; 16. Water-cooling cover plate; 17. Water-cooling sealing ring; 18. Positioning stop block; 19. Locking bolt; 21. Water-cooling connection channel; 22. Lower stop block; 23. Wedge block clamping bolt; 26. Installation bolt; 27. Communication hole; 28. Sealing block. Detailed implementation mode

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings. The description in this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention. Embodiment 1

[0029] As Figures 1 - 5 shown, a uniaxial tensile mechanical property test fixture for brittle materials in this embodiment includes a specimen 1 and a clamping structure 2 that cooperates with both ends of the specimen 1. The specimen 1 includes a gauge section 4 in the middle, two clamping ends 6, and a transition section 5 between the gauge section 4 and the clamping ends 6. The transitions among the gauge section 4, the transition section 5, and the clamping ends 6 are all smooth arcs. The specimen 1 is an integral block, and the two sides of the clamping end 6 are inclined planes. The clamping structure 2 includes a clamping body 11. A clamping groove 12 for the clamping end of the specimen 1 to enter is provided on the clamping body 11. The middle of the clamping groove 12 is a cylindrical shape that penetrates up and down. The clamping end 6 is located at the cylindrical part of the clamping groove 12 and is clamped by two arc-shaped wedge blocks 13 inserted into the cylindrical part of the clamping groove. The inclined plane of the clamping end 6 fits with the arc-shaped wedge block 13, and the arc part of the arc-shaped wedge block 13 fits with the groove wall of the clamping groove 12. A threaded connection column 3 is fixedly connected to the outer side of the clamping body 11 away from the specimen 1, and the center of the threaded connection column 3 is on the same straight line as the center of the specimen 1. Positioning stop blocks 18 that penetrate into the clamping groove 12 and position and press the upper side or the lower side of the clamping end 6 are provided on both the upper side and the lower side of the clamping body 11. The positioning stop block 18 is locked to the clamping body 11 by a locking bolt 19.

[0030] The specific operation steps of this embodiment are as follows: First, prepare the specimen 1, then prepare the arc-shaped wedge block 13 with corresponding shape and specifications according to the specimen 1. After that, insert the clamping end 6 of the test 1 into the clamping groove 12 and make the clamping end 6 located at the cylindrical part of the clamping groove 12. Then, insert the two arc-shaped wedge blocks 13 into the clamping groove 12 (in this process, it is necessary to tap and hammer them in). After the insertion is completed, the arc-shaped part of the arc-shaped wedge block 13 is close to the clamping groove 12, and the flat part will be close to the inclined surface of the clamping end 6. In this way, the clamping of the specimen can be completed. Then, lock the positioning stop block 18 with corresponding dimensions on the clamping main body 11 through the locking bolt 19. In this way, the clamping of the specimen by the fixture can be completed. Then, connect the clamping structure 2 to the testing machine pull rod mechanism through the threaded connection column 3, and drive the two clamping structures to pull away from each other through the testing machine pull rod mechanism. In this way, the tensile test of the test can be carried out.

[0031] As Figures 1 - 6 shown, in order to carry out high-temperature tests, this embodiment is further optimized. Specifically: water-cooling cavities 14 are opened on both sides of the clamping main body 11, and the two water-cooling cavities 14 are communicated through the water-cooling connection channel 21 opened inside the clamping main body 11. The water-cooling cavity 14 is equipped with a water-cooling cover plate 16, and a water-cooling sealing ring 17 is arranged at the edge of the water-cooling cover plate 16. A water-cooling joint 15 communicated with the water-cooling cavity 14 is arranged on the water-cooling cover plate 16.

[0032] This optimization scheme can ensure that the clamping main body 11 is in a water-cooling environment. Specifically, connect the two water-cooling joints 15 to the water circulation, and cool the clamping main body 11 through the flowing water during the high-temperature tensile mechanical property tests such as high-temperature creep, high-temperature tensile, and high-temperature fatigue. Embodiment 2

[0033] As Figure 7 shown, compared with Embodiment 1, in this embodiment, a lower stop block 22 is installed at the lower part of the clamping main body 11 through the locking bolt 19. The lower positioning stop block 18 is fixed on the lower stop block 22. There are no less than two threaded holes opened at the lower part of the arc-shaped wedge block 13, and the lower stop block 22 is matched with the threaded holes at the lower part of the arc-shaped wedge block 13 through the wedge block clamping bolt 23.

[0034] Compared with Embodiment 1, in this embodiment, the driving-in and subsequent locking of the arc-shaped wedge block 13 are limited. Specifically, first install the lower stop block 22, that is, install the lower positioning stop block 18. Then place the specimen 1. When the arc-shaped wedge block 13 is driven in, it will be intercepted by the lower stop block 22. In this way, it can be ensured that the arc-shaped wedge block 13 is completely driven in and the two are flush. Then, the arc-shaped wedge block 13 can be locked with the lower stop block 22 through the wedge block clamping bolt 23. In this way, the movement of the arc-shaped wedge block 13 during the subsequent test process can be avoided. Embodiment 3

[0035] As Figure 8 shown, compared with Embodiment 1, in this embodiment, the upper parts of the two arc-shaped wedges 13 are integrated through a connecting block, and the connecting block does not contact the clamping end 6 of the specimen 1.

[0036] When the arc-shaped wedge 13 of this embodiment is driven in, the two arc-shaped wedges 13 can be driven in synchronously, and it can be ensured that the two arc-shaped wedges 13 are flush. Embodiment 4

[0037] As Figures 9 - 10 shown, in this embodiment, the connection structure of the water-cooled cover plate 16 is combined with the locking structure of the arc-shaped wedge. The specific structure is as follows: the connection line of the two water-cooled joints 15 passes through the cylinder formed by the arc-shaped wedges 13, and the water-cooled joints 15 are in threaded fit with the water-cooled cover plate 16. An installation bolt 26 is fixedly connected inside the water-cooled joint 15. A water-cooled hole communicating with the inner cavity of the water-cooled joint 15 is opened outside the installation bolt 26. A communication hole 27 is opened on a part of the side surface of the water-cooled hole inside the water-cooled cavity 14. The threaded end of the installation bolt 26 passes through the clamping main body 11 and enters the threaded hole opened on the side surface of the arc-shaped wedge 13. A sealing block 28 is sleeved on the installation bolt 26. After the installation bolt 26 is installed, the sealing block 28 is close to the inner side of the water-cooled cavity 14 and generates pressure.

[0038] Compared with Embodiment 1, in this embodiment, after the arc-shaped wedge 13 is inserted and the positioning block 18 is fixed, the water-cooled cover plate 16 is installed. Specifically, the water-cooled cover plate 16 is first installed at the water-cooled cavity 14, and then the water-cooled joints 15 are connected. Specifically, the installation bolt 26 is first inserted into the water-cooled cavity 14, then passes through the clamping main body 11, and enters the threaded hole of the arc-shaped wedge 13. Then the water-cooled joint 15 is continuously rotated, so that the installation bolt 26 continues to be inserted into the threaded hole until it is completely inserted. The sealing block 28 is close to the inner side of the water-cooled cavity 14 and generates pressure. At the same time, the body of the water-cooled joint 15 will also be in threaded socket connection with the water-cooled cover plate 16. In this way, the locking of the water-cooled cover plate 16 can be realized, and at the same time, the arc-shaped wedge 13 is also locked. The structure of the installation bolt 26 can also ensure that it can transmit cold water to ensure the progress of the water-cooled cycle.

[0039] It should be noted that in this article, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0040] In this text, specific examples are used to illustrate the principles and implementation manners of the present invention. The descriptions of the above examples are only for helping to understand the method of the present invention and its core idea; the above is only the preferred implementation manner of the present invention. It should be noted that due to the limitation of literal expression and objectively there are infinite specific structures. For those of ordinary skill in the art in this technical field, without departing from the principles of the present invention, several improvements, refinements or changes can be made, or the above technical features can be combined in a proper manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, shall all be regarded as the protection scope of the present invention.

Claims

1. A uniaxial tensile mechanical property testing fixture for brittle materials, comprising a clamping structure for fitting both ends of a specimen, characterized in that, The overall sample is a block. Both sides of the clamping end of the sample are inclined planes. The clamping structure includes a clamping body. A clamping groove for the clamping end of the sample to enter is formed on the clamping body. The middle part of the clamping groove is a cylindrical shape that penetrates up and down. The clamping end is located at the cylindrical part of the clamping groove and is clamped tightly by two arc-shaped wedges inserted into the cylindrical part of the clamping groove. The inclined plane of the clamping end fits with the arc-shaped wedges, and the arc part of the arc-shaped wedges fits with the groove wall of the clamping groove.

2. The uniaxial tensile mechanical property testing fixture for brittle materials according to claim 1, wherein, The sample includes a gauge section in the middle, two clamping ends, and a transition section between the gauge section and the clamping ends. The transitions among the gauge section, the transition section, and the clamping ends are all smooth arcs.

3. A fixture for testing the uniaxial tensile mechanical properties of brittle materials according to claim 1, characterized in that, A threaded connection column is fixedly connected to the outer side of the clamping body away from the sample. The center of the threaded connection column is on the same straight line as the center of the sample.

4. A uniaxial tensile mechanical property testing fixture for brittle materials according to claim 1, characterized in that Positioning blocks that penetrate into the clamping groove and position and press the upper side or the lower side of the clamping end are arranged on both the upper side and the lower side of the clamping body. The positioning blocks are locked on the clamping body by locking bolts 19.

5. The uniaxial tensile mechanical property testing fixture for brittle materials according to claim 4, wherein, A lower block is installed on the lower part of the clamping body through a locking bolt. The lower positioning block is fixed on the lower block. There are no less than two threaded holes opened in the lower part of the arc-shaped wedge. The lower block is matched with the threaded holes in the lower part of the arc-shaped wedge through wedge clamping bolts.

6. The uniaxial tensile mechanical property testing fixture for brittle materials according to claim 1, characterized in that, The upper parts of the two arc-shaped wedges form an integral structure through a connecting block, and the connecting block does not contact the clamping end of the sample.

7. A uniaxial tensile mechanical property testing fixture for brittle materials according to claim 1 or 4, characterized in that, Water cooling cavities are opened on both sides of the clamping body, and the two water cooling cavities are communicated through a water cooling connecting channel opened inside the clamping body. A water cooling cover plate is matched with the water cooling cavity, and a water cooling sealing ring is arranged at the edge of the water cooling cover plate. A water cooling joint communicated with the water cooling cavity is arranged on the water cooling cover plate.

8. A fixture for testing the uniaxial tensile mechanical properties of brittle materials according to claim 7, characterized in that The connection line of the two water cooling joints passes through the cylinder formed by the arc-shaped wedges, and the water cooling joints are in threaded cooperation with the water cooling cover plate. An installation bolt is fixedly connected inside the water cooling joint. A water cooling hole communicated with the inner cavity of the water cooling joint is opened outside the installation bolt. Communication holes are opened on part of the side surface of the water cooling hole inside the water cooling cavity. The threaded end of the installation bolt passes through the clamping body and enters the threaded hole opened on the side surface of the arc-shaped wedge.

9. The uniaxial tensile mechanical property testing fixture for brittle materials according to claim 8, wherein, A sealing block is sleeved on the installation bolt. After the installation of the installation bolt is completed, the sealing block fits tightly against the inner side of the water cooling cavity and generates pressure.

Images