Superconducting cable bending test device

Abstract

The invention relates to the technical field of superconducting cable bending testing, and particularly discloses a superconducting cable bending testing device, which comprises a bedplate, a plurality of first through holes, a plurality of second through holes and a plurality of third through holes are formed in the bedplate, and the first through holes are square; the limiting plate is arranged on the surface of the table plate, a plurality of fourth through holes are formed in the upper portion of the limiting plate, the fourth through holes are formed above the first through holes, an arc-shaped notch is formed in the lower portion of the limiting plate, and a first binding face is formed on the side wall of the notch; the disc is arranged on the surface of the table plate, a fifth through hole is formed in the middle of the disc, the fifth through hole is formed in the second through hole, and a second binding face is arranged on the outer edge of the disc; the first bolt penetrates through the fourth through hole and the first through hole to fix the limiting plate on the table plate; and the second bolt penetrates through the fifth through hole and the second through hole to fix the disc on the bedplate. According to the superconducting cable bending test device, the superconducting cable is uniformly stressed in the bending process, the superconducting cable is prevented from being damaged, and the test accuracy is improved.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting cable bending test, in particular to a superconducting cable bending test device. Background Art

[0002] Most superconducting cable bending test equipment uses a bundling method to fix the superconducting cable on an arc-shaped groove or wall, which is prone to the following problems: 1. When bending and fixing the superconducting cable, the binding tape or fixing tool used will cause stress concentration, which may damage the tape on the outer layer of the superconducting cable, affecting the performance of the superconducting cable and the test accuracy. 2. During the test, as the bending radius decreases, the rebound force of the superconducting cable becomes greater and greater, and the cable is prone to not fitting with the groove or wall at both ends or in the middle, which will result in inaccurate test data and the inability to obtain true bending performance data. Therefore, the technical solution of this application is urgently needed to solve the above problems. Summary of the invention

[0003] The purpose of the present invention is to provide a superconducting cable bending test device, which can make the superconducting cable be evenly stressed during the bending process, avoid damaging the superconducting cable, and improve the accuracy of the test.

[0004] In order to achieve the above object, the present invention provides a superconducting cable bending test device, comprising:

[0005] A table plate, having a first through hole, a second through hole and a third through hole, wherein the first through hole is square and is provided in plurality, the first through hole extends from the upper part of the table plate to the lower part of the table plate, the third through hole is provided in plurality and is located at the lower part of the table plate, and the second through hole is located between the first through hole and the third through hole;

[0006] A limiting plate is arranged on the surface of the platform, the upper part of the limiting plate has a plurality of fourth through holes, the fourth through holes are arranged above the first through holes, the lower part of the limiting plate has an arc-shaped notch, and the side wall of the notch forms a first fitting surface;

[0007] A disc is arranged on the surface of the table, the middle of the disc has a fifth through hole, the fifth through hole is arranged on the second through hole, the outer edge of the disc has a second fitting surface, at least half of the second fitting surface is arranged in the notch, and the superconducting cable is clamped between the first fitting surface and the second fitting surface;

[0008] A first bolt, passing through the fourth through hole and the first through hole to fix the limiting plate to the table; and

[0009] A second bolt passes through the fifth through hole and the second through hole to fix the disk on the table.

[0010] In some embodiments, the first fitting surface is a curved surface that is recessed toward the limiting plate, and the second fitting surface is a curved surface that is recessed toward the disk.

[0011] In some embodiments, the disc includes an outer ring and a plurality of pillars integrally formed with the outer ring, the first end of each of the pillars is connected to the inner wall of the outer ring, the second ends of each of the pillars are connected to each other, and the fifth through hole is provided on the second end of the pillar.

[0012] In some embodiments, the thickness of the outer ring is equal to the thickness of the pillar, and the surface of the outer ring is flush with the surface of the pillar.

[0013] In some embodiments, the maximum width of the notch is a, the outer diameter of the disk is b, and the diameter of the superconducting cable is c, then a=b+2c is satisfied.

[0014] In some embodiments, when the superconducting cable is clamped between the first fitting surface and the second fitting surface, the joints at both ends of the superconducting cable extend out of the notch and are located on the third through hole, and the joints of the superconducting cable are fixed to the table by passing a binding rope through the third through hole.

[0015] In some embodiments, the platform, the limiting plate and the disc are all made of epoxy resin material.

[0016] In some embodiments, the thickness of the limiting plate is equal to the thickness of the disk, and the surface of the limiting plate is flush with the surface of the disk.

[0017] In some embodiments, the first bolt slides along the first through hole to adjust the distance between the limiting plate and the disk.

[0018] In some embodiments, the first through holes are arranged in parallel, and the plurality of third through holes are distributed in a rectangular array.

[0019] The present invention provides a superconducting cable bending test device, which has the following beneficial effects compared with the prior art:

[0020] The lower part of the limit plate is provided with an arc-shaped notch, the side wall of the notch forms a first fitting surface, the outer edge of the disc is provided with a second fitting surface, at least half of the second fitting surface is spaced in the notch, and the superconducting cable is clamped between the first fitting surface and the second fitting surface, so that the superconducting cable is subjected to uniform force during the bending process, thereby avoiding damage to the superconducting cable and improving the accuracy of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A schematic diagram of the three-dimensional structure of a superconducting cable bending test device provided in some embodiments of the present invention.

[0022] Figure 2 A schematic diagram of the three-dimensional structure of a table of a superconducting cable bending test device provided in some embodiments of the present invention.

[0023] Figure 3 A schematic diagram of the three-dimensional structure of a limiting plate and a disc of a superconducting cable bending test device provided in some embodiments of the present invention.

[0024] Figure 4 A schematic diagram of a partially enlarged structure of a limit plate of a superconducting cable bending test device provided in some embodiments of the present invention.

[0025] In the figure:

[0026] 1. table; 11. first through hole; 12. second through hole; 13. third through hole;

[0027] 2. Limiting plate; 21. Fourth through hole; 22. Notch; 23. First fitting surface;

[0028] 3. disk; 31. fifth through hole; 32. second fitting surface; 33. outer ring; 34. pillar;

[0029] 4. First bolt;

[0030] 5. Second bolt;

[0031] 6. Superconducting cable. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0033] It should be understood that, in the description of the present application, the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 application. The terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated, that is, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In addition, unless otherwise specified, "multiple" means two or more.

[0034] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] The superconducting cable targeted by the test device of the present application is a CORC (Conductor on Round Core) cable, which is a high-performance superconducting conductor designed based on the second-generation high-temperature superconducting material YBCO (yttrium barium copper oxide) tape. As a representative of the second-generation high-temperature superconducting material, YBCO tape has many excellent physical and engineering properties, such as high critical magnetic field, strong current carrying capacity and good mechanical properties. These properties make YBCO tape an ideal choice for nuclear fusion devices, particle accelerators, high-field magnets and other high-energy physics experimental equipment. Especially in high-field magnet applications, YBCO tape can maintain stable superconducting performance in extremely low temperatures and strong magnetic field environments, which is crucial to achieving efficient and compact magnet design.

[0036] CORC cable is a compact and flexible superconducting conductor. Its core design concept is to wind multiple YBCO tapes on a circular core skeleton at a specific spiral angle. This design not only makes full use of the high critical current characteristics of YBCO tapes, but also significantly reduces AC losses by optimizing the arrangement of the tapes. In addition, the flexible design of CORC cables enables them to adapt to complex geometric shapes and mechanical environments. For example, when they are wound into coils or twisted into multi-level cables, they can effectively reduce the impact of mechanical stress on superconducting performance. Compared with traditional superconducting cable structures, CORC cables have the following significant advantages:

[0037] Low AC loss: Since the YBCO tape is wound in a spiral manner, the eddy current loss of CORC cable under the alternating magnetic field is significantly reduced, which gives it a clear advantage in high-frequency or dynamic magnetic field applications.

[0038] High critical current: CORC cable can carry higher total current while maintaining high current density through the parallel structure of multiple YBCO strips.

[0039] Compact structure: The round core design and flexible structure of CORC cables make them highly adaptable in space-constrained application scenarios, such as in the complex magnet systems of nuclear fusion devices.

[0040] Easy to cable: The modular design of CORC cable makes it easy to combine with other cables or structures to form multi-level cables or complex coils to meet different engineering requirements.

[0041] However, despite the many advantages of CORC cables, they still face some challenges in practical applications. For example, during the process of winding into coils or twisting into multi-level cables, the cables are subjected to complex mechanical stresses, especially bending stress. This stress may cause changes in the microstructure of the YBCO tape, thereby affecting its superconducting properties. Therefore, studying the variation law of the critical current of CORC cables under bending stress is of great significance for optimizing their design and process parameters.

[0042] In order to accurately evaluate the performance of CORC cables under bending stress, the test device needs to be able to simulate the stress state of the cable in actual application. Specifically, the test device should have the following functions:

[0043] Precisely control bending stress: Apply controlled bending loads through mechanical structures to simulate the forces on the cable during winding or twisting.

[0044] Protect the integrity of the strip: prevent the test device from causing mechanical damage to the YBCO strip and ensure the accuracy of the test results.

[0045] Real-time monitoring of critical current: While applying bending stress, the critical current change of the cable is measured in real time to evaluate its performance degradation.

[0046] By designing an efficient test device, we can better understand the performance of CORC cables in complex mechanical environments, thus providing a scientific basis for their engineering in nuclear fusion, high-energy physics and other high-field applications. This will not only help promote the further development of CORC cable technology, but also open up new possibilities for the application of superconducting materials in more fields.

[0047] As a new type of high-temperature superconducting cable, CORC cable has broad application prospects in power transmission, magnet coils and other fields. However, in practical applications, CORC cables need to face complex mechanical environments when they are compounded into multi-level cables or wound into coils. Especially when operating in low-temperature environments, the cables not only have to withstand the stress caused by low-temperature shrinkage, but also have to deal with huge electromagnetic loads. These working conditions make the mechanical properties of CORC cables one of the key factors affecting their engineering applications. Among them, bending stress is one of the main mechanical stresses to which CORC cables are subjected during the winding or twisting process, which directly affects their critical current (i.e., the maximum current that superconducting materials can carry under specific conditions). Therefore, it is of great significance to study the influence of bending stress on the critical current of CORC cables and optimize the process parameters of winding coils or twisting multi-level cables through these laws, in order to improve the reliability and economy of their engineering applications.

[0048] In order to deeply study the performance of CORC cables under bending stress, researchers usually need to simulate the stress conditions of the cables in actual applications in a laboratory environment. Specifically, this involves applying a controllable bending load to the cable sample while measuring the critical current. However, testing directly on superconducting coils is not only costly, but also complicated to operate and difficult to achieve precise control. Therefore, researchers usually use straight conductor structures as test samples to simulate the stress state of the cable during winding or twisting. Although this testing method simplifies the experimental conditions, it still faces many challenges.

[0049] First, the existing superconducting cable bending test equipment has certain limitations in design. For example, the test equipment may cause mechanical damage to the superconducting tape on the outer layer of the CORC cable, especially under high stress conditions, and this damage may cause distortion of the test results. Secondly, since the contact surface between the superconducting cable and the test equipment cannot be completely fitted, it may cause uneven stress distribution, which in turn affects the accuracy of the test data. These problems make it difficult for existing test equipment to truly reflect the bending performance of CORC cables in actual applications, limiting the in-depth progress of related research.

[0050] In order to solve these problems, it is particularly important to design an efficient and low-cost test device. This device needs to have the following key characteristics: first, it should be able to accurately control the bending stress applied to the cable sample to ensure the repeatability and comparability of the test conditions; second, the device should avoid damage to the outer tape of the cable to maintain the integrity of the sample; finally, the device should ensure good contact between the cable and the test equipment to reduce the impact of uneven stress distribution on the test results. By optimizing the design of the test device, researchers can more accurately evaluate the critical current performance of CORC cables under bending stress, thereby providing reliable data support for practical engineering applications.

[0051] In addition, with the continuous development of superconducting technology, the application scenarios of CORC cables are also expanding. For example, in nuclear fusion devices, high-energy physics experimental equipment, and large-scale power transmission systems, the performance of CORC cables is directly related to the operating efficiency and safety of the entire system. Therefore, in-depth research on the performance of CORC cables in complex mechanical environments will not only help improve the reliability of their engineering applications, but also provide a theoretical basis for the further optimization of superconducting materials.

[0052] In summary, the bending stress of CORC cables during winding or twisting has an important influence on their critical current performance. By designing an efficient test device, researchers can more accurately simulate the stress state of the cable in actual application, thus providing a scientific basis for optimizing cable design and process parameters. This will not only help improve the engineering application value of CORC cables, but also promote the widespread application of superconducting technology in more fields.

[0053] like Figure 1-Figure 4 As shown, the superconducting cable bending test device provided by the embodiment of the present invention includes a platform 1, a limiting plate 2, a disc 3, a first bolt 4 and a second bolt 5. The limiting plate 2 is fixed to the platform 1 by the first bolt, and the disc 3 is fixed to the platform 1 by the second bolt 5.

[0054] The table 1 has a first through hole 11, a second through hole 12 and a third through hole 13. The first through hole 11 is square and is provided in plurality. The first through hole 11 extends from the upper part of the table 1 to the lower part of the table 1. The third through hole 13 is provided in plurality and is located at the lower part of the table 1. The second through hole 12 is located between the first through hole 11 and the third through hole 13. In this way, the first through hole 11 is used to install the limit plate 2, and facilitates the position adjustment of the positioning plate 2 to adapt to the clamping of superconducting cables 6 of different diameters; the second through hole 12 is used for positioning and installing the disc 3; and the third through hole 13 is used to fix the two ends of the superconducting cable 6.

[0055] The limiting plate 2 is arranged on the surface of the table 1, and the upper part of the limiting plate 2 has a plurality of fourth through holes 21, and the fourth through holes 21 are arranged above the first through holes 11. The lower part of the limiting plate 2 has an arc-shaped notch 22, and the side wall of the notch 22 forms a first fitting surface 23. The fourth through holes 21 are used for installing the limiting plate 2, and the notch 22 can cooperate with the disc 3 to clamp the superconducting cable 6, so that the superconducting cable 6 is bent.

[0056] The disc 3 is arranged on the surface of the table 1, and the middle part of the disc 3 has a fifth through hole 31, and the fifth through hole 31 is arranged on the second through hole 12. The outer edge of the disc 3 has a second fitting surface 32, and at least half of the second fitting surface 32 is arranged in the notch 22 at intervals, and the superconducting cable 6 is clamped between the first fitting surface 23 and the second fitting surface 32. The fifth through hole 31 is used for the installation of the disc 3, and the first fitting surface 23 and the second fitting surface 32 cooperate to clamp the superconducting cable 6, so that the superconducting cable 6 is subjected to uniform force during the bending process, thereby avoiding damage to the superconducting cable 6 and improving the accuracy of the test.

[0057] The first bolt 4 passes through the fourth through hole 21 and the first through hole 11 to fix the limit plate 2 on the table 1. Specifically, the limit plate 2 can be fixed on the table 1 by tightening the first bolt 4 with a nut, and the limit plate 2 can be moved along the extension direction of the first through hole 11 by loosening the first bolt 4 with a nut to adjust the distance between the limit plate 2 and the disc 3.

[0058] The second bolt 5 passes through the fifth through hole 31 and the second through hole 12 to fix the disk 3 on the table 1 .

[0059] Based on the above structural setting, the structural design of the limit plate 2 and the disc 3 is a key part, which works together to ensure that the superconducting cable 6 is subjected to uniform force during the bending test, thereby avoiding damage to the superconducting cable 6 and improving the accuracy of the test. Specifically, an arc-shaped notch 22 is designed at the lower part of the limit plate 2, and the side wall of the notch 22 forms a first fitting surface 23. At the same time, a second fitting surface 32 is designed on the outer edge of the disc 3, and at least half of the second fitting surface 32 is spaced in the notch 22 of the limit plate 2. This design enables the superconducting cable 6 to be tightly clamped between the first fitting surface 23 and the second fitting surface 32, thereby achieving uniform stress distribution during the bending process, and ensuring that the superconducting cable 6 always maintains close contact with the first fitting surface 23 and the second fitting surface 32 during the bending process, thereby avoiding the superconducting cable 6 from sliding or deflecting during the test.

[0060] like Figure 4 As shown, in some embodiments, the first bonding surface 23 is a curved surface that is concave toward the limiting plate 2, and the second bonding surface 32 is a curved surface that is concave toward the disk 3. In this way, the contact area between the first bonding surface 23 and the second bonding surface 32 and the superconducting cable 6 can be increased, thereby avoiding the phenomenon of stress concentration.

[0061] like Figure 3 As shown, in some embodiments, the disk 3 includes an outer ring 33 and a plurality of pillars 34 integrally formed with the outer ring 33, the first end of each pillar 34 is connected to the inner wall of the outer ring 33, the second ends of each pillar 34 are connected to each other, and the fifth through hole 31 is provided on the second end of the pillar 34. The structural setting of the disk 3 can reduce weight and save material usage.

[0062] In some embodiments, the thickness of the outer ring 33 is equal to the thickness of the pillar 34, and the surface of the outer ring 33 is flush with the surface of the pillar 34. In this way, the shape of the disc 3 can be kept flat, which facilitates the installation and use of the disc 3.

[0063] In some embodiments, the maximum width of the notch 22 is a, the outer diameter of the disk 3 is b, and the diameter of the superconducting cable 6 is c, then a=b+2c is satisfied. In this way, the contact positions of the superconducting cable 6 with the first bonding surface 23 and the second bonding surface 32 are subjected to balanced forces.

[0064] like Figure 1In some embodiments, when the superconducting cable 6 is clamped on the first bonding surface 23 and the second bonding surface 32, the joints at both ends of the superconducting cable 6 extend out of the gap and are located on the third through hole 13, and the joints of the superconducting cable 6 are fixed on the table 1 by passing the binding rope through the third through hole 13. In this way, the joints of the superconducting cable 6 are prevented from shaking and causing damage to the superconducting cable 6 when assembling the bending test device or connecting the test circuit.

[0065] In some embodiments, the platform 1, the limiting plate 2 and the disc 3 are all made of epoxy resin material. This has the following advantages:

[0066] Adaptability to low temperature environment: The test of superconducting cable 6 usually needs to be carried out in a low temperature environment, and epoxy resin can still maintain good mechanical properties and dimensional stability at low temperatures, which makes it an ideal choice for test device materials. Reduce damage to the cable: The surface of epoxy resin is smooth and has moderate hardness, which can avoid mechanical damage to the outer layer of the superconducting cable when clamping it. This is especially important for protecting the brittle YBCO tape. Lightweight design: Compared with metal materials, epoxy resin has a lower density, which can reduce the overall weight of the test device and facilitate experimental operation and movement of the device.

[0067] In some embodiments, the thickness of the limiting plate 2 is equal to the thickness of the disc 3, and the surface of the limiting plate 2 is flush with the surface of the disc 3. The limiting plate 2 and the disc 3 can be neatly mounted on the table 1. In this way, the testing requirements of superconducting cables 6 of different diameters can be met.

[0068] like Figure 1 and 2 As shown, in some embodiments, the first bolt 4 slides along the first through hole 11 to adjust the distance between the limiting plate 2 and the disk 3. The position of the limiting plate 2 can be fixed by tightening the first bolt 4.

[0069] like Figure 2 As shown, in some embodiments, the first through holes 11 are arranged in parallel, and the plurality of third through holes 13 are distributed in a rectangular array. By arranging a plurality of first bolts 4 to be installed in the first through holes 11, the stability of the installation structure of the limit plate 2 can be improved; and the plurality of third through holes 13 is more conducive to the joint fixation of the superconducting cable 6.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A superconducting cable bending test device, characterized in that: include: A table plate, having a first through hole, a second through hole and a third through hole, wherein the first through hole is square and is provided in plurality, the first through hole extends from the upper part of the table plate to the lower part of the table plate, the third through hole is provided in plurality and is located at the lower part of the table plate, and the second through hole is located between the first through hole and the third through hole; A limiting plate is arranged on the surface of the platform, the upper part of the limiting plate has a plurality of fourth through holes, the fourth through holes are arranged above the first through holes, the lower part of the limiting plate has an arc-shaped notch, and the side wall of the notch forms a first fitting surface; A disc is arranged on the surface of the table, the middle of the disc has a fifth through hole, the fifth through hole is arranged on the second through hole, the outer edge of the disc has a second fitting surface, at least half of the second fitting surface is arranged in the notch, and the superconducting cable is clamped between the first fitting surface and the second fitting surface; a first bolt, passing through the fourth through hole and the first through hole to fix the limiting plate to the table; as well as A second bolt passes through the fifth through hole and the second through hole to fix the disk on the table.

2. The superconducting cable bending test device according to claim 1, characterized in that: The first fitting surface is a curved surface that is recessed toward the limiting plate, and the second fitting surface is a curved surface that is recessed toward the disk.

3. The superconducting cable bending test device according to claim 1, characterized in that: The disc includes an outer ring and a plurality of pillars integrally formed with the outer ring, the first end of each pillar is connected to the inner wall of the outer ring, the second ends of each pillar are connected to each other, and the fifth through hole is provided on the second end of the pillar.

4. The superconducting cable bending test device according to claim 3, characterized in that: The thickness of the outer ring is equal to that of the pillar, and the surface of the outer ring is flush with the surface of the pillar.

5. The superconducting cable bending test device according to claim 1, characterized in that: The maximum width of the notch is a, the outer diameter of the disk is b, and the diameter of the superconducting cable is c, then a=b+2c is satisfied.

6. The superconducting cable bending test device according to claim 1, characterized in that: When the superconducting cable is clamped on the first and second fitting surfaces, the joints at both ends of the superconducting cable extend out of the notch and are located on the third through hole, and the joints of the superconducting cable are fixed on the table by passing a binding rope through the third through hole.

7. The superconducting cable bending test device according to claim 1, characterized in that: The table plate, the limiting plate and the disc are all made of epoxy resin material.

8. The superconducting cable bending test device according to claim 1, characterized in that: The thickness of the limiting plate is equal to the thickness of the disc, and the surface of the limiting plate is flush with the surface of the disc.

9. The superconducting cable bending test device according to claim 1, characterized in that: The first bolt slides along the first through hole to adjust the distance between the limiting plate and the disc.

10. The superconducting cable bending test device according to claim 1, characterized in that: The first through holes are arranged in parallel, and the plurality of third through holes are distributed in a rectangular array.

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