Insulating material low-temperature tensile test device

Abstract

The invention relates to the technical field of material performance test devices, in particular to a low-temperature tensile test device for an insulating material. The problems that an existing low-temperature stretching tool is poor in clamping and fixing effect on an insulating material in the nuclear fusion field, a sample is prone to torsion sliding in a test, stress relaxation is generated, and adaptability is insufficient are mainly solved. According to the technical scheme, the testing device comprises a clamp, a loading controller, a loading rod, a tensile sample, a force sensor, a supporting device, a testing machine reaction frame and a low-temperature environment box; the clamp comprises an upper clamp and a lower clamp; the low-temperature environment box is arranged outside the testing machine reaction frame, and the supporting device is installed outside the low-temperature environment box. According to the test device, stable positive pressure is applied to a sample, torsion sliding and stress relaxation are prevented, it is ensured that the stretching position of the sampled sample is stable and free of errors, the test failure rate is reduced, the qualification rate is increased, the clamp structures are the same, the pressing blocks are detachable, and universality and efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of material performance testing equipment, and in particular to a low-temperature tensile testing device for insulating materials. Background Technology

[0002] Insulating materials play a crucial role in nuclear fusion, primarily serving as insulation protection in cryogenic, strong magnetic field, and high-energy radiation environments. Nuclear fusion reactors, such as tokamak and laser confinement fusion devices, place extremely high demands on the performance of insulating materials, including excellent electrical insulation, cryogenic resistance, radiation resistance, and thermal stability. These materials are commonly used in critical components such as coil insulation, vacuum insulation, and thermal insulation layers to ensure safe and stable equipment operation and reduce energy loss and equipment damage.

[0003] However, existing low-temperature tensile testing fixtures used for general materials have many shortcomings when testing insulating materials in the nuclear fusion field. Specifically, these fixtures often fail to provide sufficient and stable clamping force when fixing insulating material samples. Due to the extremely high performance requirements of insulating materials in the nuclear fusion field, stress concentration easily occurs at the shoulder of the sample under large loads during low-temperature tensile testing. Existing fixtures lack effective structures to prevent torsional slippage of the sample under these conditions, which easily leads to stress relaxation, resulting in significant deviations in test results and failing to accurately reflect the true low-temperature tensile properties of the insulating material. Furthermore, existing fixtures have poor adaptability and cannot meet the diverse testing conditions required for insulating materials in the nuclear fusion field. This results in frequent instances of insecure sample fixing during testing, affecting not only the stability of test results but also reducing the pass rate, thereby impacting product production efficiency, increasing production costs, and failing to provide reliable design support for the safety and stability of nuclear fusion device operation. Therefore, this invention proposes a testing device adapted for low-temperature tensile testing of insulating materials. Summary of the Invention

[0004] The purpose of this invention is to address the problems in the prior art, such as the poor clamping and fixing effect of existing low-temperature tensile tooling on insulating materials in the field of nuclear fusion, which easily causes the sample to twist and slide during the test, resulting in stress relaxation and insufficient adaptability, and to propose a low-temperature tensile testing device for insulating materials.

[0005] The technical solution of the present invention: a low-temperature tensile testing device for insulating materials, the testing device including a clamp, a loading controller, a loading rod, a tensile sample, a force sensor, a support device, a testing machine reaction frame, and a low-temperature environment chamber;

[0006] The clamp includes an upper clamp and a lower clamp;

[0007] The low-temperature environment chamber is set outside the reaction frame of the testing machine, the support device is installed outside the low-temperature environment chamber, the loading controller is located above the support device, and the loading controller is connected to the loading rod for driving the loading rod to move.

[0008] The top end of the loading rod extends to the outside of the low-temperature environment chamber, and the force sensor is located at the top end of the loading rod;

[0009] The upper clamp is located inside the low-temperature environment chamber, and the lower clamp is located below the upper clamp. The two ends of the tensile sample are clamped and fixed by the upper clamp and the lower clamp, respectively.

[0010] The upper clamp and the lower clamp have the same structure. The upper clamp is provided with a mounting slot, and an upper pressure block for clamping and limiting one end of the stretched sample is installed in the mounting slot.

[0011] Optionally, a lower clamping block is installed on the lower clamp to clamp and limit the other end of the tensile sample.

[0012] Optionally, the lower pressure block has the same structure as the upper pressure block, and both the upper and lower pressure blocks are provided with a second locking hole. Both the upper and lower clamps are provided with a second bolt hole, and the second bolt hole and the second locking hole are fixedly connected by a locking screw.

[0013] Optionally, a sample placement slot for mounting tensile samples is provided below the mounting slot;

[0014] The lower surface of the upper pressure block is connected to an installation block that matches the shape and size of the installation slot.

[0015] Optionally, the lower surface of the mounting block is provided with an anti-slip texture to enhance the friction between the upper pressure block and the stretched sample.

[0016] Optionally, the cryogenic environment chamber is equipped with a liquid helium inlet and a liquid nitrogen inlet, both of which are connected to the interior of the cryogenic environment chamber for introducing liquid helium or liquid nitrogen into the chamber to create a cryogenic testing environment.

[0017] Optionally, a bellows is provided on the outer ring of the end of the loading rod that passes through the low-temperature environment chamber. The bellows is used to seal the low-temperature environment chamber while ensuring the movement of the loading rod.

[0018] Optionally, the bottom of the low-temperature environment chamber is provided with a testing machine workbench, and the support device is installed on the testing machine workbench to provide a support foundation for the entire testing device.

[0019] Optionally, the force sensor is used to monitor the tensile force applied to the tensile sample by the loading rod in real time and transmit the tensile force signal to an external data acquisition and processing system.

[0020] In summary, this application includes at least one of the following beneficial technical effects:

[0021] This invention, through the cooperation of the upper and lower pressure blocks and the locking screw, can apply a stable positive pressure to the surface of the tensile sample, effectively preventing the sample from tortuous sliding and stress relaxation before stress concentration occurs at the shoulder position under large loads. This ensures that the sample remains stable during the test. When the insulating material is sampled in the 0-degree direction, the sample position is stable during the tensile test, avoiding the generation of errors. The stable clamping effect reduces test failures caused by sample fixation problems, improves the test pass rate, and thus improves product production efficiency and reduces the production costs caused by repeated tests.

[0022] Furthermore, the setting of pressure blocks and locking screws ensures that the sample is firmly fixed in the fixture, which facilitates testing under various working conditions and improves adaptability and stability of test results.

[0023] Furthermore, by using an identical upper and lower clamp structure and a detachable pressure block, it is easy to replace the appropriate pressure block according to different specifications of insulation material samples, thereby further enhancing the versatility and practicality of the device and improving testing efficiency.

[0024] Furthermore, the improved pass rate in the test also increases the production efficiency of the product and reduces the production cost. It can greatly improve the efficiency of low-temperature tensile testing of insulating materials and product quality, and provide design support for the safety and stability of nuclear fusion device operation.

[0025] In summary, the test device proposed in this invention applies stable positive pressure to the sample through the cooperation of the pressure block and locking screw, preventing torsional slippage and stress relaxation, ensuring stable and error-free tensile position of the sample, reducing the failure rate and increasing the pass rate. The fixture structure is the same and the pressure block is detachable, which enhances versatility and efficiency, and can also improve product quality, providing support for the safe and stable operation of nuclear fusion devices. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 This is an exploded view of the fixture.

[0028] Figure 3 for Figure 2 Another structural diagram of the upper and middle pressure blocks;

[0029] Figure 4 yes Figure 2Another perspective structural diagram of the upper and middle clamps;

[0030] Figure 5 This is a force-displacement curve diagram of the fixture in Embodiment 1 of the present invention tested at low temperature;

[0031] Figure 6 This is a force-displacement curve diagram of the fixture in Embodiment 2 of the present invention tested at low temperature;

[0032] Figure 7 This is a force-displacement curve diagram of the fixture in Embodiment 3 of the present invention tested at low temperature;

[0033] Figure label:

[0034] 1. Upper clamp; 101. Sample placement slot; 102. Mounting slot; 103. Second bolt hole; 2. Upper pressure block; 201. Mounting block; 202. Second locking hole; 3. Locking screw; 4. Lower clamp; 5. Lower pressure block; 6. Loading controller; 7. Liquid helium inlet; 8. Loading rod; 9. Tensile sample; 10. Support device; 11. Testing machine workbench; 12. Low temperature environment chamber; 13. Testing machine reaction frame; 14. Liquid nitrogen inlet; 15. Bellows; 16. Force sensor. Detailed Implementation

[0035] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0037] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] This invention proposes a low-temperature tensile testing device for insulating materials. The testing device includes a clamp, a loading controller 6, a loading rod 8, a tensile sample 9, a force sensor 16, a support device 10, a testing machine reaction frame 13, and a low-temperature environment chamber 12. The low-temperature environment chamber 12 is located outside the testing machine reaction frame 13, the support device 10 is installed outside the low-temperature environment chamber 12, the loading controller 6 is located above the support device 10, and the loading controller 6 is connected to the loading rod 8 for driving the loading rod 8 to move. The top end of the loading rod 8 extends to the outside of the low-temperature environment chamber 12, and the force sensor 16 is located at the top end of the loading rod 8.

[0041] The cryogenic environment chamber 12 is equipped with a liquid helium inlet 7 and a liquid nitrogen inlet 14, both of which are connected to the interior of the cryogenic environment chamber 12 to introduce liquid helium or liquid nitrogen into the chamber and create a cryogenic test environment. A bellows 15 is provided around the end of the loading rod 8 that passes through the cryogenic environment chamber 12. The bellows 15 is used to seal the cryogenic environment chamber 12 while ensuring the movement of the loading rod 8. A testing machine workbench 11 is provided at the bottom of the cryogenic environment chamber 12, and a support device 10 is installed on the testing machine workbench 11 to provide a support foundation for the entire testing device. A force sensor 16 is used to monitor the tensile force applied by the loading rod 8 to the tensile sample 9 in real time and transmit the tensile force signal to an external data acquisition and processing system.

[0042] The fixture includes an upper clamp 1 and a lower clamp 4. The upper clamp 1 and the lower clamp 4 have the same structure. The upper clamp 1 and the lower clamp 4 are fixedly connected to both ends of the tensile sample 9, respectively, for limiting the tensile sample 9. The upper clamp 1 is located inside the low temperature environment chamber 12, and the lower clamp 4 is located below the upper clamp 1. Both ends of the tensile sample 9 are clamped and fixed by the upper clamp 1 and the lower clamp 4, respectively. The upper clamp 1 has a mounting slot 102, in which an upper pressure block 2 is installed to clamp and limit the installation of one end of the tensile sample 9. The lower clamp 4 has a lower pressure block 5 installed to clamp and limit the installation of the other end of the tensile sample 9.

[0043] Combination Figure 2As shown, the lower pressure block 5 has the same structure as the upper pressure block 2. Both the upper pressure block 2 and the lower pressure block 5 are provided with a second locking hole 202. Both the upper clamp 1 and the lower clamp 4 are provided with a second bolt hole 103. The second bolt hole 103 and the second locking hole 202 are fixedly connected by a locking screw 3. A sample placement groove 101 for mounting the tensile sample 9 is provided below the mounting slot 102. The lower surface of the upper pressure block 2 is connected to a mounting block 201 that matches the shape and size of the mounting slot 102. The lower surface of the mounting block 201 is provided with an anti-slip texture to enhance the friction between the upper pressure block 2 and the tensile sample 9.

[0044] In this embodiment, the two ends of the tensile insulating material sample 9 to be tested are first placed into the sample placement slot 101 of the upper clamp 1 and the corresponding slot of the lower clamp 4, respectively. Then, the mounting block 201 of the upper pressure block 2 is inserted into the mounting slot 102 of the upper clamp 1, and the corresponding structure of the lower pressure block 5 is inserted into the slot of the lower clamp 4, so that the upper pressure block 2 and the lower pressure block 5 are respectively attached to the surface of the tensile sample 9. Then, the locking screw 3 is passed through the second bolt hole 103 of the upper clamp 1 and the lower clamp 4 and the second locking hole 202 of the upper pressure block 2 and the lower pressure block 5 and tightened. The anti-slip texture on the lower surface of the mounting block 201 enhances the friction, so as to achieve a firm clamping of the tensile sample 9 and avoid slipping or twisting during the test. The installation of the lower clamp 4 and the reaction frame 13 of the testing machine is completed, and the upper clamp 1 is connected to one end of the loading rod 8.

[0045] Liquid helium or liquid nitrogen is introduced into the low-temperature environment chamber 12 through the liquid helium inlet 7 or the liquid nitrogen inlet 14 until the chamber reaches the required low-temperature conditions for the test. During this process, the loading rod 8 passes through the bellows 15 at the end of the low-temperature environment chamber 12 to maintain a sealed state, preventing leakage of the low-temperature medium inside the chamber and ensuring the stability of the low-temperature environment.

[0046] The loading controller 6 is activated, driving the loading rod 8 to move upward at a preset rate. The loading rod 8 drives the upper clamp 1 to move upward synchronously, applying tensile force to the tensile sample 9. At the same time, the force sensor 16 set at the top of the loading rod 8 monitors the magnitude of the tensile force in real time and transmits the tensile force signal to the external data acquisition and processing system, so that the staff can observe the changes in the test force in real time. The test machine workbench 11 at the bottom of the low temperature environment chamber 12 provides the bottom support for the device. The support device 10 installed on the workbench 11 further supports the low temperature environment chamber 12 and the loading controller 6 above. Together with the test machine reaction frame 13, it ensures the structural stability of the entire device during the tensile process and avoids the impact of vibration or displacement on the test accuracy. Finally, the tensile performance test of the insulating material in the low temperature environment is completed.

[0047] Example 1

[0048] like Figures 1 to 5As shown, according to the standard ASTM-D638-2022, when C is 50 mm and the thickness t is 3.5 mm; where C refers to the length of the parallel portion of the specimen and t refers to the thickness of the parallel portion of the specimen.

[0049] In this embodiment, the upper clamp 1 and lower clamp 4 of the present invention are installed on a universal testing machine, and the tensile sample 9 is installed in the sample placement slot 101, with coaxiality adjusted. Further, the upper pressure block 2 and lower pressure block 5 are installed in the corresponding positions of the clamps using eight locking screws 3, ensuring that the sample axis is coaxial with the tensile force direction of the testing machine without eccentricity. Further, the clamps and sample parts in the system are immersed in a cryogenic liquid nitrogen or liquid helium environment, such as... Figure 1 As shown. Following standard requirements, the sample environment was kept at thermal equilibrium for 15 minutes before the test. The displacement-load curve obtained from the tensile test is shown below. Figure 5 As shown. From Figure 5 It can be seen that at the beginning of the test, the load value showed a clear positive correlation trend as the displacement gradually increased. When the displacement continued to increase, the load on the curve dropped rapidly after a certain displacement. This is because the material suddenly became unstable and failed rapidly, at which point the material had already failed. The maximum destructive forces of samples 1# and 2# were 10.83kN and 11.51kN, respectively.

[0050] Example 2

[0051] like Figures 1 to 4 as well as Figure 6 As shown, according to the standard ASTM-D638-2022, when C is 30 mm and the thickness t is 3.5 mm;

[0052] In this embodiment, the upper clamp 1 and lower clamp 4 of the present invention are installed on a universal testing machine, and the tensile sample 9 is installed in the sample placement slot 101, with coaxiality adjusted. Further, the upper pressure block 2 and lower pressure block 5 are installed in the corresponding positions of the clamps using eight locking screws 3, ensuring that the sample axis is coaxial with the tensile force direction of the testing machine without eccentricity. Further, the clamps and sample parts in the system are immersed in a cryogenic liquid nitrogen or liquid helium environment, such as... Figure 1 As shown. Following standard requirements, the sample environment was kept at thermal equilibrium for 15 minutes before the test. The displacement-load curve obtained from the tensile test is shown below. Figure 6 As shown. From Figure 6It can be seen that sample #2 exhibits a similar pattern to Example 1. However, for sample #1, as the displacement gradually increases, the curve shows a local load plateau or even a decrease in load. This is due to stress release caused by delamination of the material during the tensile process. At this point, the upper pressure block 2 and the lower pressure block 5 intervene to prevent slippage and torsion of the sample during the test. Finally, the loads of curves #1 and #2 decrease rapidly after a certain displacement, which is a sign of material failure. The maximum destructive forces of samples #1 and #2 are 14.22 kN and 12.94 kN, respectively.

[0053] Example 3

[0054] like Figures 1 to 4 as well as Figure 7 As shown, according to the standard ASTM-D638-2022, when C is 50 mm and the thickness t is 4 mm;

[0055] In this embodiment, the upper clamp 1 and lower clamp 4 of the present invention are installed on a universal testing machine, and the tensile sample 9 is installed in the sample placement slot 101, with coaxiality adjusted. Further, the upper pressure block 2 and lower pressure block 5 are installed in the corresponding positions of the clamps using eight locking screws 3, ensuring that the sample axis is coaxial with the tensile force direction of the testing machine without eccentricity. Further, the clamps and sample parts in the system are immersed in a cryogenic liquid nitrogen or liquid helium environment, such as... Figure 1 As shown. Following standard requirements, the sample environment was kept at thermal equilibrium for 15 minutes before the test. The displacement-load curve obtained from the tensile test is shown below. Figure 7 As shown. From Figure 7 It can be seen that samples #1 and #2 exhibit similar patterns to those in Example 2. Upper pressure block 2 and lower pressure block 5 intervened to prevent slippage and torsion of the samples during the experiment. Ultimately, the load on curves #1 and #2 decreased rapidly after a certain displacement, leading to material failure. The maximum destructive forces for samples #1 and #2 were 13.47 kN and 13.17 kN, respectively.

[0056] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A low-temperature tensile testing device for insulating materials, characterized in that, The testing apparatus includes a clamp, a loading controller (6), a loading rod (8), a tensile sample (9), a force sensor (16), a support device (10), a testing machine reaction frame (13), and a low-temperature environment chamber (12); The clamp includes an upper clamp (1) and a lower clamp (4); The low temperature environment chamber (12) is set outside the reaction frame (13) of the testing machine, the support device (10) is installed outside the low temperature environment chamber (12), the loading controller (6) is located above the support device (10), and the loading controller (6) is connected to the loading rod (8) for driving the loading rod (8) to move. The top end of the loading rod (8) extends to the outside of the low-temperature environment chamber (12), and the force sensor (16) is disposed at the top end of the loading rod (8); The upper clamp (1) is located inside the low temperature environment chamber (12), and the lower clamp (4) is located below the upper clamp (1). The two ends of the tensile sample (9) are clamped and fixed by the upper clamp (1) and the lower clamp (4) respectively. The upper clamp (1) and the lower clamp (4) have the same structure. The upper clamp (1) is provided with a mounting slot (102), and an upper pressure block (2) for clamping and limiting the installation of one end of the stretch sample (9) is installed in the mounting slot (102).

2. The low-temperature tensile testing device for insulating materials according to claim 1, characterized in that, The lower clamp (4) is equipped with a corresponding pressure block (5) for clamping and limiting the other end of the tensile sample (9).

3. The low-temperature tensile testing device for insulating materials according to claim 2, characterized in that, The lower pressure block (5) has the same structure as the upper pressure block (2). Both the upper pressure block (2) and the lower pressure block (5) are provided with a second locking hole (202). Both the upper clamp (1) and the lower clamp (4) are provided with a second bolt hole (103). The second bolt hole (103) and the second locking hole (202) are fixedly connected by a locking screw (3).

4. The low-temperature tensile testing device for insulating materials according to claim 3, characterized in that, A sample placement slot (101) for mounting a tensile sample (9) is provided below the mounting slot (102); The lower surface of the upper pressure block (2) is connected to an installation block (201) that matches the shape and size of the installation slot (102).

5. The low-temperature tensile testing device for insulating materials according to claim 4, characterized in that, The lower surface of the mounting block (201) is provided with anti-slip texture to enhance the friction between the upper pressure block (2) and the tensile sample (9).

6. The low-temperature tensile testing device for insulating materials according to claim 1, characterized in that, The low-temperature environment chamber (12) is equipped with a liquid helium inlet (7) and a liquid nitrogen inlet (14). Both the liquid helium inlet (7) and the liquid nitrogen inlet (14) are connected to the interior of the low-temperature environment chamber (12) and are used to input liquid helium or liquid nitrogen into the low-temperature environment chamber (12) to create a low-temperature test environment.

7. The low-temperature tensile testing device for insulating materials according to claim 1, characterized in that, The loading rod (8) has a corrugated pipe (15) on the outer ring of the end that passes through the low temperature environment chamber (12). The corrugated pipe (15) is used to seal the low temperature environment chamber (12) while ensuring the movement of the loading rod (8).

8. The low-temperature tensile testing device for insulating materials according to claim 1, characterized in that, The bottom of the low temperature environment chamber (12) is provided with a test machine workbench (11), and the support device (10) is installed on the test machine workbench (11) to provide a support foundation for the entire test device.

9. The low-temperature tensile testing device for insulating materials according to claim 1, characterized in that, The force sensor (16) is used to monitor the tension applied to the tensile sample (9) by the loading rod (8) in real time and transmit the tension signal to an external data acquisition and processing system.

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