Low temperature multifunctional mechanical property test fixture

Abstract

The utility model discloses a low temperature multifunctional mechanics performance test fixture, include: first clamp bar, second clamp bar, first clamp, second clamp, clamp base and be used for loading container of liquid nitrogen, first clamp bar and second clamp bar are all along vertical direction setting, first clamp bar is located the just above of second clamp bar, the top of first clamp bar is used for with universal testing machine connection, the bottom of second clamp bar is fixed with clamp base, first clamp is fixed in the bottom of first clamp bar, second clamp is fixed in the top of second clamp bar, between first clamp and second clamp for fixed sample, the container is a cavity, and the container is covered in second clamp bar outside and is fixed with second clamp bar, and the liquid nitrogen in container can immerse sample, and there is a liquid outlet on the container, and a valve is installed on the liquid outlet. The low temperature multifunctional mechanics performance test fixture can complete the tensile test, compression and bending test of material under -196 DEG C, and tests the low temperature mechanics performance of material.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical performance testing technology, specifically relating to a low-temperature multifunctional mechanical performance testing fixture. Background Technology

[0002] Mechanical properties refer to the mechanical response characteristics of a material under different loads. Tensile, compression, and bending tests are fundamental methods for testing the mechanical properties of materials, but how to conduct mechanical property tests under low-temperature conditions has always been a challenge. This is because low-temperature mechanical property testing faces several limiting factors, such as how to provide a stable low-temperature environment and how to ensure the normal conduction of mechanical property tests under low-temperature conditions. These problems severely restrict the testing and research of the low-temperature mechanical properties of materials.

[0003] For example, CN217901429U discloses a high and low temperature testing device for testing the mechanical properties of reinforcing steel bars. This device measures the mechanical properties of reinforcing steel bars in an environment ranging from -170℃ to +100℃. It achieves the mechanical property testing of reinforcing steel bars under high and low temperature conditions through liquid nitrogen cooling and resistance wire heating. However, this patent can only achieve mechanical property testing at a minimum temperature of -170℃, and a larger environmental chamber requires a large amount of liquid nitrogen for cooling. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a low-temperature multifunctional mechanical property testing fixture that can perform tensile, compression, and bending tests on materials at -196℃ to test the low-temperature mechanical properties of the materials.

[0005] The objective of this utility model is achieved through the following technical solution.

[0006] A low-temperature multifunctional mechanical property testing fixture includes: a first clamp rod, a second clamp rod, a first clamp, a second clamp, a clamp base, and a container for loading liquid nitrogen. Both the first and second clamp rods are vertically aligned, with the first clamp rod directly above the second clamp rod. The top of the first clamp rod is connected to a universal testing machine. The bottom of the second clamp rod is fixed to the clamp base. The first clamp is fixed to the bottom of the first clamp rod, and the second clamp is fixed to the top of the second clamp rod. The first and second clamps are used to fix a sample. The container is a cavity, fitted over and fixed to the second clamp rod. The liquid nitrogen inside the container can immerse the sample. A leak is formed on the container, and a valve is installed on the leak.

[0007] In the above technical solution, a through hole for the second clamp rod to pass through is formed on the bottom surface of the container.

[0008] The above technical solution also includes: a rubber ring, which is located above the bottom surface of the container. The rubber ring is sleeved outside the second clamp rod and pressed against the inner wall of the bottom surface of the container by the first fastening nut, for sealing the through hole.

[0009] In the above technical solution, the container and the second clamp rod are coaxially arranged.

[0010] In the above technical solution, the container includes: two coaxial hollow cylinders arranged in a vertical direction, the two hollow cylinders from top to bottom being a first cylinder and a second cylinder, the radius of the second cylinder being smaller than the radius of the first cylinder, and the leakage port being located at the bottom of the first cylinder.

[0011] In the above technical solution, an insulation layer is fixedly installed on the outside of the container.

[0012] In the above technical solution, the bottom of the second clamp rod is inserted into the clamp base, and the overlapping part of the second clamp rod and the clamp base passes through a pin.

[0013] In the above technical solution, an annular protrusion is formed on the outside of the second clamping rod below the container, which is used to limit the container above the annular protrusion.

[0014] In the above technical solution, the diameter of the annular protrusion is larger than the diameter of the through hole.

[0015] The beneficial effects of this utility model are as follows:

[0016] 1. The low-temperature multifunctional mechanical property testing fixture designed in this utility model holds the specimens with different specimen clamps (tensile, compression and bending), and the specimens are immersed in liquid nitrogen throughout the mechanical property testing process, realizing the testing of the tensile, compression and bending properties of materials under low temperature (-196℃) conditions.

[0017] 2. By designing the liquid nitrogen container as a cylindrical shape with a wider top and narrower bottom, the sample can be completely immersed in liquid nitrogen while the amount of liquid nitrogen used in the lower part where there is no sample is reduced, thus saving on test waste. Attached Figure Description

[0018] Figure 1 A cross-sectional view of a low-temperature multifunctional mechanical property testing fixture;

[0019] Figure 2 A three-dimensional structural diagram of a low-temperature multifunctional mechanical property testing fixture;

[0020] Figure 3 This is a three-dimensional structural diagram of a multifunctional mechanical property testing fixture, where a is a tensile fixture, b is a bending fixture, and c is a compression fixture.

[0021] Figure 4 This is a diagram showing the room temperature / low temperature tensile displacement stress curve of copper-aluminum alloy.

[0022] Figure 5 This is a schematic diagram of the tension clamp structure;

[0023] Figure 6 This is a schematic diagram of the compression clamp.

[0024] Wherein, 1 is the first clamp rod, 2 is the second clamp rod, 2-1 is the annular protrusion, 2-2 is the second fastening nut, 3 is the first clamp, 3-1 is the first through groove, 3-2 is the first baffle, 3-3 is the first pressure plate, 4 is the second clamp, 4-1 is the second through groove, 4-2 is the second baffle, 4-3 is the second pressure plate, 4-4 is the sleeve, 4-5 is the hard alloy pad, 5 is the clamp base, 5-1 is the pin, 6 is the container, 6-1 is the leak outlet, 6-2 is the valve, 6-3 is the rubber ring, 6-4 is the first fastening nut, and 7 is the insulation layer. Detailed Implementation

[0025] The technical solution of this utility model will now be described in detail with reference to the accompanying drawings.

[0026] Example 1

[0027] A low-temperature multifunctional mechanical property testing fixture includes: a first clamp rod 1, a second clamp rod 2, a first clamp 3, a second clamp 4, a clamp base 5, and a container 6 for loading liquid nitrogen. Both the first clamp rod 1 and the second clamp rod 2 are vertically arranged, with the first clamp rod 1 located directly above the second clamp rod 2. The top of the first clamp rod 1 is used to connect to a universal testing machine (not shown in the figure). The bottom of the second clamp rod 2 is fixedly attached to the clamp base 5. The first clamp 3 is fixedly attached to the bottom of the first clamp rod 1, and the second clamp 4 is fixedly attached to the top of the second clamp rod 2. The first clamp 3 and the second clamp 4 are used to fix the sample. The first clamp rod 1 and the second clamp rod 2 are identical, and the first clamp 3 and the second clamp 4 are one of a tensile clamp, a bending clamp, and a compression clamp.

[0028] Container 6 is a cavity comprising two coaxial hollow cylinders arranged vertically. From top to bottom, the two hollow cylinders are a first cylinder and a second cylinder, which are connected. The radius of the second cylinder is smaller than that of the first cylinder. Container 6 is fitted over and fixed to the second clamping rod 2. Container 6 and the second clamping rod 2 are coaxially arranged. A through hole for the second clamping rod 2 is formed on the bottom surface of container 6. To achieve sealing after liquid nitrogen is loaded into container 6, a hole is formed above the bottom surface of container 6. A rubber ring 6-3 is provided, which is fitted over the second clamp rod 2 and pressed against the inner wall of the bottom surface of the container 6 by the first fastening nut 6-4; the liquid nitrogen in the container 6 can immerse the sample, and a leakage port 6-1 is formed on the bottom of the first cylinder of the container 6, and a valve 6-2 is installed on the leakage port 6-1; an insulation layer 7 is fixedly installed on the outside of the container 6; an annular protrusion 2-1 is formed on the outside of the second clamp rod 2 below the container 6, and the diameter of the annular protrusion 2-1 is larger than the diameter of the through hole, which is used to limit the container 6 above the annular protrusion 2-1;

[0029] The bottom of the second clamp rod 2 is inserted into the clamp base 5. The annular protrusion 2-1 is located above the clamp base 5. The bottom of the annular protrusion 2-1 contacts the clamp base 5. The outer side of the annular protrusion 2-1 is threaded, and a second fastening nut 2-2 is installed on the thread. The overlapping part of the second clamp rod 2 and the clamp base 5 passes through a pin 5-1. The second clamp rod 2 and the clamp base 5 can be fixed by the pin 5-1 and the second fastening nut 2-2 on the outer side of the annular protrusion 2-1.

[0030] The diameter of the first cylinder of container 6 is 120mm, the diameter of the second cylinder is 50mm, the diameter of the clamp rod is 40mm, and the first fastening nut 6-4 is an M40 type nut.

[0031] Figures 1-2 The image shows a low-temperature multifunctional mechanical property testing fixture, taking a tensile clamp as an example. Figure 3 The diagram shows the first clamp rod 1, the second clamp rod 2, and the clamp base 5, which are respectively equipped with a tension clamp (a), a bending clamp (b), and a compression clamp (c).

[0032] Example 2

[0033] The low-temperature tensile properties of copper-aluminum alloys were tested using the low-temperature multifunctional mechanical property testing fixture (tensile fixture) of Example 1. The specific steps are as follows:

[0034] Step 1: Adjust the height of the universal testing machine beam so that the distance between the tensile clamps is suitable for the tensile specimen (copper-aluminum alloy), and fix the tensile specimen between the first clamp 3 and the second clamp 4.

[0035] Step 2: Add liquid nitrogen to container 6;

[0036] Step 3: Start calculating from the time the sample is immersed in liquid nitrogen. After the sample has been immersed for 10 minutes and the liquid nitrogen level has stabilized, start the tensile test. During the tensile test, add liquid nitrogen from time to time to ensure that the sample is always immersed in liquid nitrogen.

[0037] Step 4: After completing the tensile test, open valve 6-2 to recover most of the liquid nitrogen from the leak port 6-1. The remaining small amount of liquid nitrogen is poured out and recovered after removing container 6. The fractured sample is then removed.

[0038] Comparative Example 1

[0039] A method for testing the low-temperature tensile properties of copper-aluminum alloys is disclosed. The method employs the low-temperature multifunctional mechanical property testing fixture (tensile fixture) of Example 1 to test the room-temperature tensile properties of copper-aluminum alloys. The method is essentially the same as in Example 2, except that liquid nitrogen is not added. The tensile properties of the copper-aluminum alloys at room temperature (20±5℃) are tested.

[0040] From Example 2 ( Figure 4 (in the example "-196℃") and Comparative Example 1 ( Figure 4 The tensile properties of copper-aluminum alloys at room temperature and low temperature (within 20℃) are as follows: Figure 4 As shown.

[0041] Example 3

[0042] like Figure 5 As shown, based on Example 1, in the tensile fixture, both the first fixture and the second fixture are plates with a certain thickness. The bottom of the first fixture has a first through groove 3-1 (a shoulder groove, the first through groove penetrating the plate horizontally), and the top of the second fixture has a second through groove 4-1 (a shoulder groove, the second through groove penetrating the plate horizontally). The width of the first through groove gradually decreases from top to bottom, and the width of the second through groove gradually decreases from bottom to top. A first baffle 3-2 is fixedly installed on each of the two sides of the first through groove, and a second baffle 4-2 is fixedly installed on each of the two sides of the second through groove. The two ends of the sample are larger than the middle position. When placing the sample into the tensile fixture, one end of the sample is inserted into the first through groove from the side of the plate, and the other end of the sample is inserted into the second through groove from the side of the plate. Then, a first baffle is fixedly installed on each side of the first through groove, and a second baffle is fixedly installed on each side of the second through groove, thus completing the sample installation.

[0043] Example 4

[0044] Because the low-temperature multifunctional mechanical property testing fixture of this utility model operates at low temperatures, it is inconvenient to contact the sample during use. To prevent the sample from tipping over during compression, a compression fixture is designed, as follows: Figure 6As shown, the top of the first clamp is threaded onto the first clamp rod 1, and the first clamp includes a first pressure plate 3-3. The bottom of the second clamp is threaded onto the second clamp rod 2, and the second clamp includes a second pressure plate 4-3, a sleeve 4-4, and a carbide pad 4-5. The sleeve is fixed to the upper surface of the second pressure plate, and the interior of the sleeve is used to place the sample (the height of the sleeve is greater than the sample). The carbide pad is located inside the sleeve and placed above the sample. The top of the carbide pad protrudes from the top surface of the sleeve, and the shape of the carbide pad matches the shape inside the sleeve. The function of the sleeve is to prevent the sample from being knocked over during the addition of liquid nitrogen.

[0045] The present invention has been described above by way of example. It should be noted that, without departing from the core of the present invention, any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort fall within the protection scope of the present invention.

Claims

1. A low-temperature multifunctional mechanical property testing fixture, characterized in that, include: The system comprises a first clamp rod (1), a second clamp rod (2), a first clamp (3), a second clamp (4), a clamp base (5), and a container (6) for loading liquid nitrogen. Both the first clamp rod (1) and the second clamp rod (2) are vertically aligned. The first clamp rod (1) is located directly above the second clamp rod (2). The top of the first clamp rod (1) is used to connect to the universal testing machine. The bottom of the second clamp rod (2) is fixedly attached to the clamp base (5). The first clamp (3) is also fixedly attached. At the bottom of the first clamp rod (1), the second clamp (4) is fixedly mounted on the top of the second clamp rod (2). The first clamp (3) and the second clamp (4) are used to fix the sample. The container (6) is a cavity. The container (6) is sleeved on the second clamp rod (2) and fixedly mounted to the second clamp rod (2). The sample is immersed in liquid nitrogen in the container (6). A leak (6-1) is formed on the container (6). A valve (6-2) is installed on the leak (6-1).

2. The low-temperature multifunctional mechanical property testing fixture according to claim 1, characterized in that, A through hole for the second clamp rod (2) is formed on the bottom surface of the container (6).

3. The low-temperature multifunctional mechanical property testing fixture according to claim 2, characterized in that, Also includes: A rubber ring (6-3) is located above the bottom surface of the container (6). The rubber ring (6-3) is fitted outside the second clamp rod (2) and pressed against the inner wall of the bottom surface of the container (6) by the first fastening nut (6-4) to seal the through hole.

4. The low-temperature multifunctional mechanical property testing fixture according to claim 3, characterized in that, The container (6) is coaxially arranged with the second clamp rod (2).

5. The low-temperature multifunctional mechanical property testing fixture according to claim 4, characterized in that, The container (6) includes two coaxial hollow cylinders arranged in a vertical direction. The two hollow cylinders from top to bottom are a first cylinder and a second cylinder. The radius of the second cylinder is smaller than the radius of the first cylinder. The leakage port (6-1) is located at the bottom of the first cylinder.

6. The low-temperature multifunctional mechanical property testing fixture according to claim 5, characterized in that, An insulation layer (7) is fixed to the outside of the container (6).

7. The low-temperature multifunctional mechanical property testing fixture according to claim 6, characterized in that, The bottom of the second clamp rod (2) is inserted into the clamp base (5), and the overlapping part of the second clamp rod (2) and the clamp base (5) passes through a pin (5-1).

8. The low-temperature multifunctional mechanical property testing fixture according to claim 7, characterized in that, An annular protrusion (2-1) is formed on the outside of the second clamping rod (2) below the container (6) to limit the container (6) above the annular protrusion (2-1).

9. The low-temperature multifunctional mechanical property testing fixture according to claim 8, characterized in that, The diameter of the annular protrusion (2-1) is larger than the diameter of the through hole.

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