A clamp for tensile test and a method for fixing a tensile specimen in a tensile test

Abstract

The embodiments of the present invention provide a clamp for tensile testing and a method for fixing a tensile specimen in a tensile test, and relate to the field of clamps. The clamp for tensile testing includes a first clamping assembly for fixing one end of the tensile specimen and a second clamping assembly for fixing the other end; the first clamping assembly and the second clamping assembly are both composed of a first clamping outer plate, a second clamping outer plate and a clamping inner plate, and a smaller clamping inner plate is used to form a housing space for fixing the tensile specimen at the second end. When in use, the first ends of the first clamping assembly and the second clamping assembly are clamped in the clamp provided by the tensile machine, and the two ends of the tensile specimen are respectively fixed in the housing spaces of the first clamping assembly and the second clamping assembly. It avoids the deviation, skewing, unevenness, etc. caused by directly clamping the tensile specimen on the tensile machine, improves the stability of manual operation, and ensures the accuracy of the tensile test results. It is particularly suitable for clamping small specimens in micro-tensile tests.

Description

Technical Field

[0001] The invention relates to the field of clamps, and in particular to a clamp for a tensile test and a method for fixing a tensile specimen in the tensile test. Background Art

[0002] From the perspective of engineering application and cost, the current traditional test method for testing the mechanical properties of metal materials requires a large number of repetitive tests. However, the size of conventional specimens is too large, which will lead to a large waste of raw materials of metal specimens. Reducing the size of specimens is conducive to saving metal raw materials, thereby reducing costs. Therefore, the micro-specimen micro-tensile test method can save raw materials and maximize the use of metal raw materials.

[0003] The micro-specimen micro-tensile test method is a new test method. The sample size used is relatively small, which is conducive to evaluating the influence of local areas on the mechanical properties of materials. At the same time, the small sample micro-tensile test method can also be used for non-destructive sampling and testing of in-service equipment and safety assessment. This method can be used to measure the elastic limit, elongation, tensile strength, yield strength, creep properties at high temperatures, etc. of materials, and is expected to be widely used in various industrial fields.

[0004] Although the small sample micro-tensile test method has many application advantages, the small tensile test still faces the following problems in the actual process: (1) The small size of the micro-specimen will cause the clamping part of the specimen to be too small during the tensile test, which puts higher requirements on the clamp used for the clamping part stretching; (2) The small size of the micro-specimen will easily cause the specimen to be biased, distorted, or uneven during the tensile loading process, all of which affect the accuracy of the test results; (3) During the stretching process, the micro-specimens have some differences in the experimental results due to their smaller stretching size, unstable manual operation, and different operating procedures; (4) Due to their smaller size, micro-specimens are not suitable for the common tensile testing machines on the market.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The first object of the present invention is to provide a clamp for tensile testing, aiming to more conveniently fix the tensile specimen, improve the stability of manual operation, and thus improve the accuracy of the test results.

[0007] The second object of the present invention is to provide a method for fixing a tensile specimen in a tensile test, which is easy to operate and reduces the influence of stability problems caused by manual operation on the test results.

[0008] The embodiments of the present invention can be implemented as follows:

[0009] An embodiment of the present invention provides a clamp for a tensile test, which is used to fix a tensile specimen, and includes a first clamping assembly for fixing one end of the tensile specimen and a second clamping assembly for fixing the other end opposite to the tensile specimen;

[0010] The first clamping assembly and the second clamping assembly each include a first clamping outer plate, a second clamping outer plate arranged opposite to the first clamping outer plate, and a clamping inner plate located between the first clamping outer plate and the second clamping outer plate. The first clamping outer plate, the second clamping outer plate and the clamping inner plate each have a first end for being clamped by a clamp provided by the stretching machine and a second end opposite to the first end. The extension direction from the first end to the second end is the length direction. The distance that the clamping inner plate extends in the length direction is less than the distance that the first clamping outer plate and the second clamping outer plate extend in the length direction, so as to form an accommodating space for fixing the tensile specimen at the second end of the first clamping outer plate and the second clamping outer plate.

[0011] In a preferred embodiment of the present invention, it also includes a first fixing column and a second fixing column. The first clamping outer plate, the second clamping outer plate and the clamping inner plate are all provided with connecting holes on the plate surface close to the first end. The first fixing column sequentially passes through the connecting hole on the first clamping component to fix the first clamping component at the first end; the second fixing column sequentially passes through the connecting hole on the second clamping component to fix the second clamping component at the first end.

[0012] In a preferred embodiment of the present invention, the lengths of the first fixing column and the second fixing column are both smaller than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate and the clamping inner plate.

[0013] In a preferred embodiment of the present invention, the first clamping outer plate, the second clamping outer plate and the clamping inner plate each have at least two connecting holes, and the number of the first fixing columns and the second fixing columns matches the number of the corresponding connecting holes.

[0014] In a preferred embodiment of the present invention, it also includes a first hanging column and a second hanging column, and the two end plate surfaces of the tensile specimen are both provided with sample hanging holes, and the first clamp hanging hole and the second clamp hanging hole matched with the sample hanging hole are respectively provided on the plate surfaces of the first clamping outer plate and the second clamping outer plate near the second end; the first hanging column sequentially passes through the first clamp hanging hole on the first clamping component, the sample hanging hole on the tensile specimen and the second clamp hanging hole on the first clamping component, so that one end of the tensile specimen is hung in the accommodating space of the first clamping component; the second hanging column sequentially passes through the first clamp hanging hole on the second clamping component, the sample hanging hole on the tensile specimen and the second clamp hanging hole on the second clamping component, so that the other end of the tensile specimen is hung in the accommodating space of the second clamping component;

[0015] Preferably, the thickness of the clamped inner plate is greater than the thickness of the tensile specimen.

[0016] In a preferred embodiment of the present invention, the first suspension column and the second suspension column are both threaded columns, and the sample suspension hole, the first fixture suspension hole and the second fixture suspension hole are all threaded holes matching the threaded columns.

[0017] In a preferred embodiment of the present invention, the lengths of the first suspension column and the second suspension column are both greater than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate and the clamping inner plate.

[0018] In a preferred embodiment of the present invention, it also includes a first fixing nut and a second fixing nut, there are two first fixing nuts and two second fixing nuts, and the two first fixing nuts are used to be installed at both ends of the first suspension column, and the two second fixing nuts are used to be installed at both ends of the second suspension column.

[0019] In a preferred embodiment of the present invention, the length of the first suspension column is greater than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate, the clamping inner plate and the two first fixing nuts; the length of the second suspension column is greater than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate, the clamping inner plate and the two second fixing nuts.

[0020] An embodiment of the present invention further proposes a method for fixing a tensile specimen in a tensile test, which uses the above-mentioned tensile test clamp to fix the tensile specimen; preferably, the fixing method includes: clamping the first ends of the first clamping assembly and the second clamping assembly in the clamp provided by the tensile machine, and fixing the two ends of the tensile specimen in the accommodating spaces of the first clamping assembly and the second clamping assembly, respectively; preferably, the tensile specimen is a tiny specimen in a micro-tensile test.

[0021] The beneficial effects of the embodiments of the present invention include: in the embodiments of the present invention, the two ends of the tensile specimen are clamped by the first clamping assembly and the second clamping assembly, and the first clamping assembly and the second clamping assembly are both composed of a first clamping outer plate, a second clamping outer plate and a clamping inner plate, and a smaller clamping inner plate is used to form a holding space for fixing the tensile specimen at the second end. When in use, the first ends of the first clamping assembly and the second clamping assembly are clamped in the clamp provided by the stretching machine, and the two ends of the tensile specimen are respectively fixed in the holding spaces of the first clamping assembly and the second clamping assembly. The clamp in the embodiments of the present invention avoids the occurrence of deflection, skewing, unevenness, etc. caused by directly clamping the tensile specimen on the stretching machine, improves the stability of manual operation, and thus ensures the accuracy of the tensile test results.

[0022] It is particularly pointed out that the tensile test fixture in the embodiment of the present invention is particularly suitable for micro-tensile testing and is used to clamp small specimens. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the structure of a clamp for a tensile test provided in an embodiment of the present invention;

[0025] Figure 2 for Figure 1 Exploded view of the grip for the medium tensile test;

[0026] Figure 3 for Figure 1 Diagram of the use status of the clamp for medium tensile test.

[0027] Icons: 100-clamp for tensile test; 10-tensile specimen; 11-specimen hanging hole; 110-first clamping assembly; 120-second clamping assembly; 111-first clamping outer plate; 112-second clamping outer plate; 113-clamping inner plate; 200-clamp provided with the tensile machine; 001-first end; 002-second end; 003-accommodating space; 1141-first fixing column; 1142-second fixing column; 115-connecting hole; 1161-first hanging column; 1162-second hanging column; 1171-first fixture hanging hole; 1172-second fixture hanging hole; 1181-first fixing nut; 1182-second fixing nut. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0033] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0034] Please refer to Figure 1 and Figure 2 The present embodiment provides a clamp 100 for a tensile test, which is used to fix a tensile specimen 10 in a tensile test, and specifically includes a first clamping assembly 110 for fixing one end (such as the top end) of the tensile specimen 10 and a second clamping assembly 120 for fixing the other end (such as the bottom end) of the tensile specimen 10.

[0035] The specific structures of the first clamping assembly 110 and the second clamping assembly 120 may be substantially the same, and in some embodiments may be symmetrically arranged. The first clamping assembly 110 may also be referred to as an upper clamping assembly, and the second clamping assembly 120 may also be referred to as a lower clamping assembly.

[0036] Furthermore, the first clamping assembly 110 and the second clamping assembly 120 each include a first clamping outer plate 111, a second clamping outer plate 112 arranged opposite to the first clamping outer plate 111, and a clamping inner plate 113 located between the first clamping outer plate 111 and the second clamping outer plate 112; the first clamping outer plate 111, the second clamping outer plate 112 and the clamping inner plate 113 each have a first end 001 for being clamped by the clamp 200 provided by the stretching machine and a second end 002 opposite to the first end 001, the extension direction from the first end 001 to the second end 002 is the length direction, and the distance that the clamping inner plate 113 extends in the length direction is less than the distance that the first clamping outer plate 111 and the second clamping outer plate 112 extend in the length direction, so as to form a accommodating space 003 for fixing the tensile specimen 10 at the second end 002 of the first clamping outer plate 111 and the second clamping outer plate 112.

[0037] When using, please refer to Figure 2 and Figure 3The first ends 001 of the first clamping assembly 110 and the second clamping assembly 120 are clamped in the clamp 200 provided with the tensile machine, and the two ends of the tensile specimen 10 are respectively fixed in the accommodation spaces 003 of the first clamping assembly 110 and the second clamping assembly 120. The clamp in the embodiment of the present invention avoids the occurrence of deflection, skewing, unevenness, etc. caused by directly clamping the tensile specimen 10 on the tensile machine, improves the stability of manual operation, and thus ensures the accuracy of the tensile test results.

[0038] Generally speaking, the clamping surface of the clamp 200 provided in the stretching machine is a plane, and the first end 001 of the first clamping component 110 and the second clamping component 120 is clamped by the clamping surface instead of directly clamping the tensile specimen 10. This is convenient to operate and can improve the tensile test efficiency of the micro-tensile specimen 10 and the accuracy of the experimental results.

[0039] In a preferred embodiment of the present invention, the tensile test fixture 100 further includes a first fixing column 1141 and a second fixing column 1142. The first clamping outer plate 111, the second clamping outer plate 112 and the clamping inner plate 113 are all provided with connecting holes 115 on the plate surface close to the first end 001. The first fixing column 1141 sequentially passes through the connecting hole 115 on the first clamping assembly 110 to fix the first clamping assembly 110 at the first end 001; the second fixing column 1142 sequentially passes through the connecting hole 115 on the second clamping assembly 120 to fix the second clamping assembly 120 at the first end 001. The specific shapes of the first fixing column 1141, the second fixing column 1142 and the connecting hole 115 are not limited, and can be cylindrical and circular holes. The sizes of the fixing column and the connecting hole 115 are matched, so that the position of the fixing column can be fixed after passing through the connecting hole 115, and it is not easy to move left and right.

[0040] In a preferred embodiment of the present invention, the lengths of the first fixing column 1141 and the second fixing column 1142 are both less than the sum of the thicknesses of the first clamping outer plate 111, the second clamping outer plate 112, and the clamping inner plate 113. This ensures that the outer surfaces of the first clamping outer plate 111 and the second clamping outer plate 112 are flat and have no protruding structures, which facilitates the clamping of the clamp 200 provided with the stretching machine.

[0041] In a preferred embodiment of the present invention, there are at least two connection holes 115 on the first clamping outer plate 111, the second clamping outer plate 112 and the clamping inner plate 113, and the number of the first fixing column 1141 and the second fixing column 1142 is adapted to the number of the corresponding connection holes 115. In some embodiments, there may be two as shown in the figure, which can further enhance the stability of the fixation and prevent loosening during the test.

[0042] In a preferred embodiment of the present invention, the first suspension column 1161 and the second suspension column 1162 are also included. The two end plates of the tensile specimen 10 are provided with a specimen suspension hole 11. The first clamping outer plate 111 and the second clamping outer plate 112 are provided with a first clamp suspension hole 1171 and a second clamp suspension hole 1172 respectively on the plate surface close to the second end 002 and matching with the specimen suspension hole 11. The first suspension column 1161 passes through the first clamp suspension hole 1171 on the first clamping assembly 110, the first clamp suspension hole 1171 on the tensile specimen 10, and the second clamp suspension hole 1172 on the first clamping assembly 110. The sample hanging hole 11 of the first clamp assembly 110 and the second clamp hanging hole 1172 on the first clamp assembly 110 are connected to make one end of the tensile sample 10 hang in the accommodation space 003 of the first clamp assembly 110; the second hanging column 1162 passes through the first clamp hanging hole 1171 on the second clamp assembly 120, the sample hanging hole 11 on the tensile sample 10 and the second clamp hanging hole 1172 on the second clamp assembly 120 in sequence, so that the other end of the tensile sample 10 is hung in the accommodation space 003 of the second clamp assembly 120. The fixing method of the tensile sample 10 in the embodiment of the present invention is simple and easy, it does not directly contact the clamp 200 provided by the tensile machine, is easy to operate, and is easy to disassemble.

[0043] In other embodiments, the first suspension column 1161 and the second suspension column 1162 may not be used for fixing, but other fixing methods may be used.

[0044] In some embodiments, the thickness of the clamping inner plate 113 is greater than the thickness of the tensile specimen 10 , so that the tensile specimen 10 can be better suspended in the accommodating space 003 for performing a tensile test.

[0045] In some embodiments, the first suspension column 1161 and the second suspension column 1162 are both threaded columns, and the sample suspension hole 11, the first fixture suspension hole 1171 and the second fixture suspension hole 1172 are all threaded holes that match the threaded columns. Fixing by means of threaded columns and threaded holes can make the fixation more stable and also facilitate disassembly.

[0046] Optionally, the lengths of the first suspension column 1161 and the second suspension column 1162 are both greater than the sum of the thicknesses of the first clamping outer plate 111, the second clamping outer plate 112, and the clamping inner plate 113, so as to improve the stability of the fixation and facilitate disassembly. Further, it also includes a first fixing nut 1181 and a second fixing nut 1182, and the first fixing nut 1181 and the second fixing nut 1182 are both two, and the two first fixing nuts 1181 are used to be installed at both ends of the first suspension column 1161, and the two second fixing nuts 1182 are used to be installed at both ends of the second suspension column 1162. Through the arrangement of the first fixing nut 1181 and the second fixing nut 1182, the two ends of the first suspension column 1161 and the second suspension column 1162 are locked, thereby increasing the stability of the suspension of the tensile specimen 10. After the test is completed, the first fixing nut 1181 and the second fixing nut 1182 can be disassembled, the first suspension column 1161 and the second suspension column 1162 can be removed, and then the tensile specimen 10 can be removed.

[0047] Optionally, the length of the first suspension column 1161 is greater than the sum of the thicknesses of the first clamping outer plate 111, the second clamping outer plate 112, the clamping inner plate 113, and the two first fixing nuts 1181; the length of the second suspension column 1162 is greater than the sum of the thicknesses of the first clamping outer plate 111, the second clamping outer plate 112, the clamping inner plate 113, and the two second fixing nuts 1182. By further increasing the lengths of the first suspension column 1161 and the second suspension column 1162, the stability of the connection is improved.

[0048] Optionally, the effective clamping area is an area for clamping the inner plate 113 , and its height is greater than the distance between the connecting hole 115 and the first end 001 , and less than the distance between the first clamp hanging hole 1171 and the first end 001 .

[0049] The embodiment of the present invention also provides a method for fixing a tensile specimen 10 in a tensile test, which uses the above-mentioned clamp 100 for tensile test to fix the tensile specimen 10, and the fixing method includes: clamping the first end 001 of the first clamping assembly 110 and the second clamping assembly 120 in the clamp 200 provided by the tensile machine, and fixing the two ends of the tensile specimen 10 in the accommodation space 003 of the first clamping assembly 110 and the second clamping assembly 120 respectively. The clamp in the embodiment of the present invention avoids the occurrence of deflection, skewing, unevenness, etc. caused by directly clamping the tensile specimen 10 on the tensile machine, improves the stability of manual operation, and thus ensures the accuracy of the tensile test results.

[0050] It is particularly pointed out that the tensile test fixture 100 in the embodiment of the present invention is particularly suitable for micro-tensile testing and is used to clamp small specimens also called micro-specimens. The specific size is not limited and can be 3 cm, 2 cm or even smaller.

[0051] The method of using the tensile test fixture 100 provided in this embodiment is as follows:

[0052] (1) Connecting the first clamping assembly 110 (upper clamping assembly): align the connection holes 115 on the first clamping outer plate 111, the second clamping outer plate 112 and the clamping inner plate 113, and fix them by passing the first fixing column 1141 through the connection holes 115 in sequence.

[0053] (2) The fixed first clamping assembly 110 is clamped by a plane clamp provided by the stretching machine, and the size of the clamping part is the same as the size area of ​​the clamping inner plate 113.

[0054] (3) Place the top end of the tensile specimen 10 in the accommodating space 003 of the first clamping assembly 110, and sequentially pass the first clamp hanging hole 1171, the specimen hanging hole 11, and the second clamp hanging hole 1172 through the first hanging column 1161 to hang the tensile specimen 10 in the accommodating space 003 of the first clamping assembly 110, and lock the two ends of the first hanging column 1161 with two first fixing nuts 1181.

[0055] (4) Connecting the second clamping assembly 120 (lower clamping assembly): align the connection holes 115 on the first clamping outer plate 111, the second clamping outer plate 112 and the clamping inner plate 113, and fix them by passing the second fixing column 1142 through the connection holes 115 in sequence.

[0056] (5) The fixed second clamping assembly 120 is clamped by a plane clamp provided by the stretching machine, and the size of the clamping part is the same as the size area of ​​the clamping inner plate 113.

[0057] (6) By controlling and fine-tuning the relative positions of the first clamping assembly 110 and the second clamping assembly 120, the first clamp hanging hole 1171 and the second clamp hanging hole 1172 on the second clamping assembly 120 are aligned with the specimen hanging hole 11 at the bottom end of the tensile specimen 10. By placing the bottom end of the tensile specimen 10 in the accommodating space 003 of the first clamping assembly 110, and passing the second hanging column 1162 through the first clamp hanging hole 1171, the specimen hanging hole 11 and the second clamp hanging hole 1172 in sequence, the tensile specimen 10 is hung in the accommodating space 003 of the second clamping assembly 120, and the two ends of the second hanging column 1162 are locked by two second fixing nuts 1182.

[0058] (7) The universal material testing machine is started to perform a tensile test. After the test is completed, the first clamping assembly 110 and the second clamping assembly 120 are disassembled and the tensile specimen 10 is taken out.

[0059] The tensile test fixture 100 provided in this embodiment has at least the following advantages: (1) The device has a small number of parts and is flexible and convenient to disassemble. The sample can be easily taken out after the experiment. It occupies a small area, has low cost, and has a simple production process. (2) The device is convenient for locating the sample position, ensuring that the sample and the force are in a coaxial state, and avoiding unnecessary errors. (3) The device is easy to operate. The clamping process only needs to clamp the area of ​​the same size as the upper and lower internal clamping modules, and the tensile sample 10 only needs to be suspended by the hanging cylinder, which can effectively prevent the tensile clamp from slipping or not clamping the sample due to loose loading. (4) The present invention is suitable for clamping a variety of sheet samples. The size of the clamp can be adjusted accordingly according to existing needs. The operation is simple and the mold can be reused.

[0060] In summary, the embodiment of the present invention provides a clamp 100 for tensile testing, which clamps the two ends of the tensile specimen 10 through a first clamping assembly 110 and a second clamping assembly 120. The first clamping assembly 110 and the second clamping assembly 120 are both composed of a first clamping outer plate 111, a second clamping outer plate 112 and a clamping inner plate 113. The clamping inner plate 113 with a smaller length is used to form a receiving space 003 for fixing the tensile specimen 10 at the second end 002. When in use, the first ends 001 of the first clamping assembly 110 and the second clamping assembly 120 are clamped in the clamp 200 provided by the tensile machine, and the two ends of the tensile specimen 10 are respectively fixed in the receiving spaces 003 of the first clamping assembly 110 and the second clamping assembly 120. The clamp in the embodiment of the present invention avoids the occurrence of deflection, skewing, unevenness, etc. caused by directly clamping the tensile specimen 10 on the tensile machine, improves the stability of human operation, and thus ensures the accuracy of the tensile test results.

[0061] It is particularly pointed out that the tensile test fixture 100 in the embodiment of the present invention is particularly suitable for use in micro-tensile tests and is used to clamp small specimens.

[0062] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A clamp for a tensile test, used to fix a tensile specimen, characterized in that: It includes a first clamping assembly for fixing one end of a tensile specimen and a second clamping assembly for fixing the other end opposite to the tensile specimen; The first clamping assembly and the second clamping assembly each include a first clamping outer plate, a second clamping outer plate arranged opposite to the first clamping outer plate, and a clamping inner plate located between the first clamping outer plate and the second clamping outer plate. The first clamping outer plate, the second clamping outer plate and the clamping inner plate each have a first end for being clamped by a clamp provided by the stretching machine and a second end opposite to the first end. The extension direction from the first end to the second end is the length direction. The distance that the clamping inner plate extends in the length direction is smaller than the distance that the first clamping outer plate and the second clamping outer plate extend in the length direction, so as to form an accommodation space for fixing the tensile specimen at the second end of the first clamping outer plate and the second clamping outer plate.

2. The tensile test fixture according to claim 1, characterized in that: It also includes a first fixing column and a second fixing column, the first clamping outer plate, the second clamping outer plate and the clamping inner plate are all provided with connecting holes on the plate surface close to the first end, and the first fixing column passes through the connecting holes on the first clamping assembly in sequence, so that the first clamping assembly is fixed at the first end; The second fixing columns sequentially pass through the connecting holes on the second clamping assembly so that the second clamping assembly is fixed at the first end.

3. The tensile test fixture according to claim 2, characterized in that: The lengths of the first fixing column and the second fixing column are both less than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate, and the clamping inner plate.

4. The tensile test fixture according to claim 2 or 3, characterized in that: There are at least two connection holes on the first clamping outer plate, the second clamping outer plate and the clamping inner plate, and the number of the first fixing columns and the second fixing columns is consistent with the number of the corresponding connection holes.

5. The tensile test fixture according to claim 1, characterized in that: It also includes a first hanging column and a second hanging column, the two end plate surfaces of the tensile specimen are both provided with specimen hanging holes, and the first clamping outer plate and the second clamping outer plate are respectively provided with a first clamp hanging hole and a second clamp hanging hole matching the specimen hanging holes on the plate surfaces close to the second end; The first hanging column passes through the first fixture hanging hole on the first clamping assembly, the specimen hanging hole on the tensile specimen, and the second fixture hanging hole on the first clamping assembly in sequence, so that one end of the tensile specimen is hung in the accommodating space of the first clamping assembly; The second hanging column passes through the first clamp hanging hole on the second clamping assembly, the specimen hanging hole on the tensile specimen, and the second clamp hanging hole on the second clamping assembly in sequence, so that the other end of the tensile specimen is hung in the accommodating space of the second clamping assembly.

6. The tensile test fixture according to claim 5, characterized in that: The thickness of the clamping inner plate is greater than the thickness of the tensile specimen.

7. The tensile test fixture according to claim 5, characterized in that: The first suspension column and the second suspension column are both threaded columns, and the sample suspension hole, the first fixture suspension hole and the second fixture suspension hole are all threaded holes matched with the threaded columns.

8. The tensile test fixture according to claim 7, characterized in that: The lengths of the first suspension column and the second suspension column are both greater than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate, and the clamping inner plate.

9. The tensile test fixture according to claim 7, characterized in that: It also includes a first fixing nut and a second fixing nut, wherein the first fixing nut and the second fixing nut are both two in number, and the two first fixing nuts are used to be installed at both ends of the first suspension column, and the two second fixing nuts are used to be installed at both ends of the second suspension column.

10. The tensile test fixture according to claim 9, characterized in that: The length of the first suspension column is greater than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate, the clamping inner plate and the two first fixing nuts; The length of the second suspension column is greater than the sum of the thicknesses of the first clamping outer plate, the second clamping outer plate, the clamping inner plate and the two second fixing nuts.

11. A method for fixing a tensile specimen in a tensile test, characterized in that: The tensile test fixture described in any one of claims 1 to 10 is used to fix the tensile test specimen.

12. The fixing method according to claim 11, characterized in that: The fixing method comprises: clamping the first ends of the first clamping assembly and the second clamping assembly in a clamp provided by a stretching machine, and fixing the two ends of the stretching specimen in the accommodation spaces of the first clamping assembly and the second clamping assembly, respectively.

13. The fixing method according to claim 12, characterized in that: The tensile specimen is a tiny specimen in a micro-tensile test.

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