A method for testing critical characteristics of superconducting tape in multiple deformation modes

Abstract

The invention discloses a critical characteristic test method of a superconducting tape under multiple deformation modes, comprising: selecting the multiple deformation mode of the superconducting tape to be tested; if the bending deformation mode is selected, further selecting the curvature specification, fixing the component that meets the current specification at the lower end of the G10 pull rod three, selecting a whole strip of appropriate length to perform a critical test of the bending deformation, and performing online stress adjustment; if the stretching and twisting deformation mode is selected, selecting the stretching and torsion angle specifications of a replaceable clamping component, fixing the replaceable clamping component that meets the angle specification at the lower end of the G10 pull rod three, and selecting two strips of appropriate length to perform a critical test of the stretching and twisting deformation; the invention finds the error value caused by the thermal stress disturbance by setting an axisymmetric structure and comparing and observing the stress difference between the superconducting tape without current loading and the superconducting tape with current loading, thereby eliminating the interference factors in the superimposed stress and improving the accuracy of the stress test.

Description

Technical Field

[0001] The invention relates to the field of critical characteristic testing of superconducting tapes, and in particular to a critical characteristic testing method of superconducting tapes in a multi-deformation mode. Background Art

[0002] Since 1911, when Dutch physicist Melinnes discovered the superconducting properties of mercury at low temperatures, namely "zero resistance" and "Meissner effect", it has shown attractive application prospects. Currently, superconducting materials and related technologies are increasingly being used in many fields such as scientific research, transportation, electricity, energy, biomedicine, national defense and military. However, due to the constraints of extremely low temperature working environment and high costs, as well as the supply of core raw materials, low-temperature superconducting applications are facing increasingly significant crises and challenges. In recent years, with the further acceleration of the practical application of high-temperature superconducting tapes, many high-tech companies, research institutions and university laboratories in the world have successively carried out research based on the testing and winding of high-temperature superconducting tapes.

[0003] Engineering practice and research have shown that high-temperature superconducting materials will experience changes in critical characteristics under external mechanical pressure or deformation, which is mainly manifested as the degradation of critical current Ic, and even the loss of superconducting characteristics. It can be seen that the characteristics of high-temperature superconducting materials are not only affected by their physical properties, but also significantly affected by their mechanical properties. In practical applications, they are inevitably subjected to external mechanical loads, electromagnetic loads, temperature disturbances and other types of loads. Therefore, the development of superconducting tape mechanics problems under extreme environmental conditions is directly related to the safe design and stable operation of high-temperature superconducting magnets. It is urgent to develop corresponding test platforms and evaluation methods that can provide extreme multi-field environments and characterize the thermal, electromagnetic and mechanical macro-microscopic properties of high-temperature superconducting electromagnetic materials.

[0004] Existing superconducting tape stress testing device Figure 8 As shown, one of the problems it has is that it is impossible to adjust stress online: the traditional method is to adjust the deformation stress in advance at room temperature: the strip is pasted to the upper surface of the beam, and the distance between the left and right fulcrums of the beam is increased by rotating the bidirectional lead screw nut between the two sides of the beam, thereby applying tensile stress to the strip. The disadvantage is that once the deformation stress is adjusted and it is placed in an ultra-low temperature environment for testing, the stress cannot be adjusted online during the test. Because the same mechanism - the beam - is used to support the strip and the bidirectional lead screw adjustment nut, manual adjustment of stress and deformation can only be performed at room temperature, and superconducting tape testing can only be performed at ultra-low temperature. Since it is the same mechanism and cannot be disassembled, the traditional method cannot adjust stress online while testing. The second problem it has is that it is impossible to achieve multi-deformation mode testing of bending, stretching and torsion using the same transmission mechanism, such as Figure 8The method of using a bidirectional screw to adjust the nut is limited to tensile and bending tests, but cannot achieve torsion tests. If torsion tests are to be achieved, another transmission mechanism must be used. The third problem is that the disturbance error of thermal stress cannot be eliminated in stress testing. When current is applied to the strip, thermal stress will be generated. At this time, the stress acting on the superconducting strip is a superimposed stress. For example, when testing the bending stress of the superconducting strip, the read stress contains the interference factor of thermal stress due to the loading of current. However, due to the superposition, the error caused by thermal stress cannot be eliminated. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for testing the critical characteristics of a superconducting tape in a multiple deformation mode. One purpose is to solve the problem that the traditional method cannot adjust stress online. The second purpose is to solve the problem that polygonal mode testing cannot be performed in the same transmission mechanism device. The third purpose is to solve the problem that the disturbance error of thermal stress cannot be eliminated in stress testing.

[0006] The present invention adopts the following technical solutions to solve the technical problems:

[0007] A method for testing critical characteristics of a superconducting tape in a multi-deformation mode is based on a device for testing critical characteristics of a superconducting tape in a multi-deformation mode, the device comprising: a skeleton support and vacuum chamber 1 consisting of an upper and lower layer, an adjustable tension component 2 passing through the upper and lower layers of the skeleton support and vacuum chamber 1 and extending downward to an ultra-low temperature test layer, a strip clamping tool 3 fixed to the bottom end of the adjustable tension component 2, and a current lead terminal 4 arranged on the superconducting tape to be tested; the skeleton support and vacuum chamber 1, the upper layer of which is a room temperature environment, used for the adjustable tension component 2 to adjust stress online in a room temperature environment; the lower layer of which is a vacuum environment, provided with a vacuum chamber, and the vacuum chamber is used to isolate hot air; the The strip clamping tool 3 includes a fixed clamping component 3-1 and a replaceable clamping component. The replaceable clamping component includes a replaceable bending tool clamping component 3-2 and a replaceable stretching and torsion tool clamping component 3-3. Through the combination of different clamping components, various deformation modes of stretching, bending and torsion of the strip can be realized; the replaceable stretching and torsion tool clamping component 3-3 adopts an axisymmetric device that can eliminate non-reference stress interference. When the axisymmetric device performs a stretching or torsion strip test, two strips are fixed on the test device respectively, one of which is a reference strip, and the reference strip is used to test the reference stress, and the other strip is a non-reference strip, and the non-reference strip is used to test the superimposed stress;

[0008] The adjustable tension component 2 includes three layers: upper, middle and lower. The upper layer corresponds to the room temperature environment of the skeleton support and the vacuum chamber 1, and the middle layer corresponds to the vacuum environment of the skeleton support and the vacuum chamber 1. The upper layer is provided with an adjusting nut 2-2 and a pressure sensor 2-3, and the middle layer is provided with a metal bellows 2-4. The upper and middle layers share a stainless steel adjustable screw 2-1, and the lower layer is provided with a G10 pull rod 2-5. The adjustable tension component 2 realizes stress loading on the strip by rotating the adjusting nut 2-2 and changing the stroke of the adjustable screw 2-1. The tension borne by the strip is obtained by reading the changes in the pressure sensor 2-3, wherein the pressure borne by the strip is δ=F / A, wherein δ: stress; F: tension; A: cross-sectional area of ​​the strip; the non-reference stress interference includes thermal stress interference;

[0009] The third layer of the adjustable tension component 2 is provided with three G102-5 pull rods, the middle one is G10 pull rod three 2-5-3, and the two sides are G10 pull rod one 2-5-1 and G10 pull rod two 2-5-2. The G10 pull rod one 2-5-1 and G10 pull rod two 2-5-2 on both sides are connected to the stainless steel adjustable screw rod 2-1, and the middle G10 pull rod three 2-5-3 is fixed and not connected to the stainless steel adjustable screw rod (2-1). When the adjusting nut (2-2) is rotated, the G10 pull rod one 2-5-1 and G10 pull rod two 2-5-2 move up and down with the metal bellows 2-4. Since the strip is fixed at the ends of the G10 pull rod one 2-5-1 and G10 pull rod two 2-5-2, the strip also moves up and down with the metal bellows 2-4.

[0010] The fixed clamping component 3-1 is fixedly connected to the G10 pull rod 1 2-5-1 and the G10 pull rod 2-5-2 by bolts, and moves up and down together with the adjustable tension rod during the stress loading process;

[0011] The replaceable bending tool clamping component 3-2 includes a cylindrical bracket 3-2-1 and different curvature supporting cylinders 3-2-2, wherein the cylindrical bracket 3-2-1 is fixed on the G10 pull rod 2-5-3, and the different curvature supporting cylinders 3-2-2 are placed on the cylindrical bracket 3-2-1. The strip passes around the different curvature supporting cylinders 3-2-2 to simulate the critical characteristics test under different bending radii.

[0012] Its characteristic is that the test method comprises the following steps:

[0013] Step 1: Select multiple deformation modes of the superconducting tape to be tested, wherein the multiple deformation modes include bending deformation mode, stretching deformation mode and twisting deformation mode;

[0014] Step 2: If the bending deformation mode is selected, the curvature specification of the replaceable bending tool clamping component 3-2 is further selected, and the replaceable bending tool clamping component 3-2 that meets the current specification is fixed at the lower end of the G10 pull rod three 2-5-3, and a whole strip of appropriate length is selected for critical testing of bending deformation, and online stress adjustment is performed; if the stretching and torsion deformation mode is selected, the stretching and torsion angle specifications of the replaceable stretching and torsion tool clamping component 3-3 are further selected, and the replaceable stretching and torsion tool clamping component 3-3 that meets the angle specifications is fixed at the lower end of the G10 pull rod three 2-5-3, and two strips of appropriate length are selected for critical testing of stretching and torsion deformation, one of which is a reference strip used to test the reference stress, and the other is a non-reference strip used to test the superimposed stress, and online stress adjustment is performed;

[0015] The critical test of bending deformation is carried out as follows:

[0016] 1) Select a replaceable bending fixture clamping component 3-2, and select a curvature cylinder (3-2-2) with a suitable bending diameter, wherein the curvature of the curvature cylinder 3-2-2 includes 5mm, 10mm, 12mm, 15mm, and 20mm;

[0017] 2) Cut a superconducting tape with a length of 24~28cm, wipe the surface of the superconducting tape with alcohol, non-woven fabric and other materials, paste the low-temperature strain gauge at the appropriate position, and weld the voltage lead;

[0018] 3) Fix the pre-treated strip on the fixed clamping component 3-1 and the replaceable bending tool clamping component 3-2;

[0019] 4) Connect the critical characteristic test device to the cryostat, lead out the current lead, strain test lead, voltage lead, and evacuate the critical characteristic test device and the cryostat;

[0020] 5) When the vacuum is better than 5×10-3Pa, turn on the refrigerator to cool down, and use the heating plate to stabilize the refrigerator at a constant temperature, load the critical current and stress of the superconducting tape, and record the voltage signal on the superconducting tape in real time to determine whether it is quenched;

[0021] 6) Until the superconducting tape quenches, record the current I, voltage V, tension, and strain to obtain the superconducting critical characteristic parameters, then reheat and complete the test;

[0022] 7) Adjust the bending stress online: read the data on the strain gauge. If the stress does not meet the requirement, manually adjust the adjusting nut 2-2 until the bending stress reaches the set requirement.

[0023] The critical test of tensile and torsional deformation is carried out as follows:

[0024] 1) Select a replaceable stretching and torsion fixture clamping component 3-3, and select a stretching and torsion pressing block 3-3-1 with a suitable angle, wherein the angles of the stretching and torsion pressing block 1 include 0 degrees, 5 degrees, 10 degrees, 15 degrees, and 20 degrees;

[0025] 2) Cut two superconducting tapes with a length of 12~16cm, wipe the surface of the superconducting tapes with alcohol, non-woven fabric and other materials, paste low-temperature strain gauges at appropriate positions, and weld voltage leads;

[0026] 3) respectively fix the two pre-treated strips on the respective fixing clamping components 3-1, the tensile torsion pressing block 1 3-3-1, and the tensile torsion pressing block 2 3-3-2 on both sides of the axis in an axisymmetric manner;

[0027] 4) connecting the critical characteristics test device to the cryostat, connecting the lead-out current lead and the voltage lead to one of the superconducting tapes, and evacuating the critical characteristics test device and the cryostat;

[0028] 5) When the vacuum is better than 5×10-3Pa, turn on the refrigerator to cool down, and use the heating plate to stabilize the refrigerator at a constant temperature, load the critical current and stress of the superconducting tape, and record the voltage signal on the superconducting tape in real time to determine whether it is quenched;

[0029] 6) During the critical current loading process of the tape, the stress difference between the superconducting tape without current loading and the superconducting tape with current loading is compared and observed. The difference is mainly caused by the disturbance of thermal stress.

[0030] 7) Adjust the tensile and torsional stress online: read the data on the strain gauge on each strip. If the tensile and torsional stresses do not meet the requirements, manually adjust the adjusting nut 2-2 until the tensile and torsional stresses meet the set requirements.

[0031] 8) Until the superconducting tape quenches, record the current I, voltage V, tension, and strain to obtain the superconducting critical characteristic parameters, then reheat and complete the test.

[0032] Advantages and effects of the present invention

[0033] 1. The present invention divides the adjustable tension component into three layers: upper, middle and lower, and the three layers support and depend on each other: the upper and lower layers are inseparable from the vacuum cavity of the middle layer, otherwise the upper and lower layers cannot isolate the hot air and the online adjustment effect cannot be achieved; the middle layer is also inseparable from the support of the upper and lower layers. Without the upper and lower layers, the vacuum pumping of the middle layer loses its meaning. After the combination, it produces a much better effect than before the combination, and realizes the online adjustment of stress test.

[0034] 2. The present invention divides the test device into a common part, a non-common part, a fixed structure and a non-fixed structure in the common part, and a fixed structure and a non-fixed structure in the non-common part, thereby realizing stress adjustment of multiple deformation modes through the same transmission device. The prior art in which each type of tooling only performs stress testing of one mode is improved to the present invention in which at least a dozen stress tests can be performed through the same tooling, achieving a leap from quantitative change to qualitative change.

[0035] 3. The present invention sets an axisymmetric structure and compares and observes the stress difference between the superconducting tape without loading current and the superconducting tape with loading current during the loading process of the critical current of the tape, thereby finding the error value caused by thermal stress disturbance, thereby eliminating the interference factors in the superimposed stress and improving the accuracy of stress testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The overall structure diagram of the multi-deformation mode-bending deformation testing device is invented;

[0037] Figure 2 To invent the structure diagram of the G10 pull rod of the adjustable tension component;

[0038] Figure 3 For the invention of the replaceable bending tooling clamping component structure diagram;

[0039] Figure 4 The overall structure diagram of the multi-deformation mode-tension torsion test device is invented;

[0040] Figure 5 A three-dimensional diagram of the clamping parts of the replaceable stretching and torsion tooling invented;

[0041] Figure 6 A top view of the clamping parts of the replaceable stretching and torsion tooling invented;

[0042] Figure 7 Skeleton support and vacuum chamber;

[0043] Figure 8 Superconducting tape stress testing device using traditional methods;

[0044] Fig. 9 Flow chart of the critical characteristics testing method of the present invention;

[0045] 1: Skeleton support and vacuum chamber; 1-1: Vacuum chamber; 2: Adjustable tension component; 2-1: Adjustable screw; 2-2: Adjusting nut; 2-3: Pressure sensor; 2-4: Metal bellows; 2-5: G10 pull rod; 2-5-1: G10 pull rod one; 2-5-2: G10 pull rod two; 2-5-3: G10 pull rod three; 3: Strip clamping tool; 3-1: Fixed clamping component; 3-2: Replaceable bending tool clamping component; 3-2-1: Cylindrical bracket; 3-2-2: Support cylinders with different curvatures; 3-3: Replaceable stretching and torsion tool clamping component; 3-3-1: Stretching and torsion pressure block one; 3-3-2: Stretching and torsion pressure block two; 4: Current lead. DETAILED DESCRIPTION

[0046] The present invention will be further explained below in conjunction with the accompanying drawings:

[0047] Design principle of the present invention

[0048] 1. Design principle of online adjustable stress. The key problem of online stress adjustment is to arrange the parts of the adjustable tension component 2 that operate at room temperature and the parts that operate at ultra-low temperature in different temperature environments, specifically: the adjustable screw 2-1, the adjusting nut 2-2, and the pressure sensor 2-3 are arranged at room temperature; the G10 pull rod 1, G10 pull rod 2, and G10 pull rod 3 are arranged at ultra-low temperature; but in this way, if the sealing of the joint between the parts that operate at room temperature and the parts that operate at ultra-low temperature is not done well, hot air leakage will occur. In order to solve the problem of hot air leakage at the joint of the two parts, the adjustable tension component of the present invention is divided into three sections: upper, middle, and lower. A vacuum chamber is added to the middle section to isolate the hot air.

[0049] 2. Design principle of using the same transmission mechanism to realize multi-deformation test: The first key point is to divide the test device into common parts and non-common parts. Among the three main parts, there are two common parts: skeleton support and vacuum chamber 1, and adjustable tension component 2, and the non-common part is the strip clamping fixture 3; the second key point is to divide the non-common strip clamping fixture 3 into a fixed clamping component 3-1, and variable clamping components 3-2 and 3-3; the third key point is to divide the common adjustable tension component 2 into a fixed G10 pull rod 2-5-3, and a movable G10 pull rod one 2-5-1 and G10 pull rod two 2-5-2; the fixed G10 pull rod three 2-5-3 corresponds to the variable clamping components 3-2 and 3-3 of the strip clamping fixture 3, and the movable part G10 pull rod one and G10 pull rod two correspond to the superconducting tape. In short, the big aspects are divided into common parts and non-common parts. The small aspects are divided into fixed parts and movable parts among the common parts, and the non-common parts are further divided into fixed parts and movable parts.

[0050] 3. Design principle for eliminating thermal stress interference factors. First, testing interference factors is a need for practical applications. The test device of the present invention is designed to test critical current. Loading stress only adds an environment in practical applications. There is stress in practical applications, and how much stress is needed to be tested. Therefore, the stress to which the strip is subjected in practical applications should be superimposed stress, which includes not only the thermal stress of the current, but also mechanical stress. Second, testing interference factors is limited to tensile and torsion tests. The bending test cannot be tested because the entire strip is used. Only when there are two strips can one side be subjected to the baseline stress and the other side to the superimposed stress. Third, the axisymmetric device uses the adjustable screw 2-1 and the G10 pull rod three 2-5-3 as the axis, and the two sides of them are symmetrically provided with G10 pull rod one 2-5-1 of equal length, G10 pull rod two 2-5-2, strips of equal length, and relatively arranged tensile torsion blocks two 3-3-2 from top to bottom. Fourth, a strain gauge is attached to each of the left and right strips, and the strain gauge is used to read the stress received by the strip. Fourth, during the loading process of the critical current of the strip, the stress difference between the superconducting strip without loading current and the superconducting strip with loading current is compared and observed. The difference is mainly caused by the disturbance of thermal stress.

[0051] Based on the above principles, the present invention relates to a method for testing critical characteristics of a superconducting tape under multiple deformation modes.

[0052] A method for testing the critical characteristics of a superconducting tape under multiple deformation modes Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9As shown, the test method is based on a critical characteristic test device for a superconducting tape in a multi-deformation mode, the device comprising: a skeleton support and a vacuum chamber 1 consisting of an upper and lower layer, an adjustable tension member 2 passing through the upper and lower layers of the skeleton support and the vacuum chamber 1 and extending downward to the ultra-low temperature test layer, a strip clamping tool 3 fixed to the bottom end of the adjustable tension member 2, and a current lead terminal 4 arranged on the superconducting tape to be tested; the skeleton support and the vacuum chamber 1, the upper layer of which is a room temperature environment, is used for the adjustable tension member 2 is used to adjust stress online at room temperature; its lower layer is a vacuum environment, and a vacuum chamber is provided, and the vacuum chamber is used to isolate heat; the strip clamping tool 3 includes a fixed clamping component 3-1 and a replaceable clamping component, and the replaceable clamping component includes a replaceable bending tool clamping component 3-2 and a replaceable stretching and torsion tool clamping component 3-3. Through the combination of different clamping components, various deformation modes of stretching, bending and torsion of the strip can be realized; the replaceable stretching and torsion tool clamping component 3-3 is as follows Figure 2 , Figure 5 As shown, an axisymmetric device capable of eliminating non-reference stress interference is used. When the axisymmetric device performs a tensile or torsion strip test, two strips are fixed on the test device respectively, one of which is a reference strip used to test the reference stress, and the other is a non-reference strip used to test the superimposed stress; the non-reference stress interference includes the interference of thermal stress;

[0053] The adjustable tension member 2 is as follows Figure 1 , Figure 4 As shown, it includes three layers: upper, middle and lower. The upper layer corresponds to the room temperature environment of the skeleton support and the vacuum chamber 1, and the middle layer corresponds to the vacuum environment of the skeleton support and the vacuum chamber (1). The upper layer is provided with an adjusting nut 2-2 and a pressure sensor 2-3, and the middle layer is provided with a metal bellows 2-4. The upper and middle layers share a stainless steel adjustable screw 2-1, and the lower layer is provided with a G10 pull rod 2-5. The adjustable tension component 2 realizes stress loading on the strip by rotating the adjusting nut 2-2 to change the stroke of the adjustable screw 2-1. By reading the change of the pressure sensor 2-3, the tension borne by the strip is obtained, wherein the pressure borne by the strip is δ=F / A, wherein δ: stress; F: tension; A: cross-sectional area of ​​the strip;

[0054] The third layer of the adjustable tension member 2 is as follows Figure 1 , Figure 4As shown, there are three G102-5 tie rods, the middle one is G10 tie rod three 2-5-3, and the two sides are G10 tie rod one 2-5-1 and G10 tie rod two 2-5-2. The G10 tie rod one 2-5-1 and G10 tie rod two 2-5-2 on both sides are connected to the stainless steel adjustable screw 2-1, and the middle G10 tie rod three 2-5-3 is fixed and not connected to the stainless steel adjustable screw (2-1). When the adjusting nut (2-2) is rotated, the G10 tie rod one 2-5-1 and G10 tie rod two 2-5-2 move up and down with the metal bellows 2-4. Since the strip is fixed at the ends of the G10 tie rod one 2-5-1 and G10 tie rod two 2-5-2, the strip also moves up and down with the metal bellows 2-4.

[0055] The fixed clamping component 3-1 is as follows Figure 2 As shown, the fixed connection is achieved with the G10 tie rod 1 2-5-1 and the G10 tie rod 2 2-5-2 respectively by bolts, and during the stress loading process, it moves up and down together with the adjustable tie rod;

[0056] The replaceable bending tool clamping component 3-2 is as follows Figure 3 As shown, it includes a cylindrical support 3-2-1 and supporting cylinders 3-2-2 with different curvatures, wherein the cylindrical support 3-2-1 is fixed on the G10 pull rod 2-5-3, and the supporting cylinders 3-2-2 with different curvatures are placed on the cylindrical support 3-2-1. The strip passes around the supporting cylinders 3-2-2 with different curvatures to simulate the critical characteristics test under different bending radii;

[0057] Its characteristic is that the test method is Fig. 9 As shown, the following steps are included:

[0058] Step 1: Select multiple deformation modes of the superconducting tape to be tested, wherein the multiple deformation modes include bending deformation mode, stretching deformation mode and twisting deformation mode;

[0059] Step 2: If the bending deformation mode is selected, the curvature specification of the replaceable bending tool clamping component 3-2 is further selected, and the replaceable bending tool clamping component 3-2 that meets the current specification is fixed at the lower end of the G10 pull rod three 2-5-3, and a whole strip of appropriate length is selected for critical testing of bending deformation, and online stress adjustment is performed; if the stretching and torsion deformation mode is selected, the stretching and torsion angle specifications of the replaceable stretching and torsion tool clamping component 3-3 are further selected, and the replaceable stretching and torsion tool clamping component 3-3 that meets the angle specifications is fixed at the lower end of the G10 pull rod three 2-5-3, and two strips of appropriate length are selected for critical testing of stretching and torsion deformation, one of which is a reference strip used to test the reference stress, and the other is a non-reference strip used to test the superimposed stress, and online stress adjustment is performed;

[0060] The critical test of bending deformation is carried out as follows:

[0061] 1) Select a replaceable bending fixture clamping component 3-2, and select different curvature support cylinders 3-2-2 with suitable bending diameters, wherein the curvatures of the different curvature support cylinders 3-2-2 include 5mm, 10mm, 12mm, 15mm, and 20mm;

[0062] 2) Cut a superconducting tape with a length of 24~28cm, wipe the surface of the superconducting tape with alcohol, non-woven fabric and other materials, paste the low-temperature strain gauge at the appropriate position, and weld the voltage lead;

[0063] 3) Fix the pre-treated strip on the fixed clamping component 3-1 and the replaceable bending tool clamping component 3-2;

[0064] 4) Connect the critical characteristic test device to the cryostat, lead out the current lead, strain test lead, voltage lead, and evacuate the critical characteristic test device and the cryostat;

[0065] 5) When the vacuum is better than 5×10-3Pa, turn on the refrigerator to cool down, and use the heating plate to stabilize the refrigerator at a constant temperature, load the critical current and stress of the superconducting tape, and record the voltage signal on the superconducting tape in real time to determine whether it is quenched;

[0066] 6) Until the superconducting tape quenches, record the current I, voltage V, tension, and strain to obtain the superconducting critical characteristic parameters, then reheat and complete the test;

[0067] 7) Adjust the bending stress online: read the data on the strain gauge. If the stress does not meet the requirement, manually adjust the adjusting nut 2-2 until the bending stress reaches the set requirement.

[0068] The critical test of tensile and torsional deformation is carried out as follows:

[0069] 1) Select a replaceable stretching and torsion fixture clamping component 3-3, and select a stretching and torsion pressing block 3-3-1 with a suitable angle, wherein the angles of the stretching and torsion pressing block 1 include 0 degrees, 5 degrees, 10 degrees, 15 degrees, and 20 degrees;

[0070] 2) Cut two superconducting tapes with a length of 12~16cm, wipe the surface of the superconducting tapes with alcohol, non-woven fabric and other materials, paste low-temperature strain gauges at appropriate positions, and weld voltage leads;

[0071] 3) respectively fix the two pre-treated strips on the respective fixing clamping components 3-1, the tensile torsion pressing block 1 3-3-1, and the tensile torsion pressing block 2 3-3-2 on both sides of the axis in an axisymmetric manner;

[0072] 4) connecting the critical characteristics test device to the cryostat, connecting the lead-out current lead and the voltage lead to one of the superconducting tapes, and evacuating the critical characteristics test device and the cryostat;

[0073] 5) When the vacuum is better than 5×10-3Pa, turn on the refrigerator to cool down, and use the heating plate to stabilize the refrigerator at a constant temperature, load the critical current and stress of the superconducting tape, and record the voltage signal on the superconducting tape in real time to determine whether it is quenched;

[0074] 6) During the critical current loading process of the tape, the stress difference between the superconducting tape without current loading and the superconducting tape with current loading is compared and observed. The difference is mainly caused by the disturbance of thermal stress.

[0075] 7) Adjust the tensile and torsional stress online: read the data on the strain gauge on each strip. If the tensile and torsional stresses do not meet the requirements, manually adjust the adjusting nut 2-2 until the tensile and torsional stresses meet the set requirements.

[0076] 8) Until the superconducting tape quenches, record the current I, voltage V, tension, and strain to obtain the superconducting critical characteristic parameters, then reheat and complete the test.

[0077] It should be emphasized that the above specific embodiments are merely explanations of the present invention, and they are not limitations of the present invention. After reading this specification, those skilled in the art can make modifications to the above embodiments without any creative contribution as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for testing critical characteristics of a superconducting tape in a multi-deformation mode, the method being based on a device for testing critical characteristics of a superconducting tape in a multi-deformation mode, the device comprising: The invention relates to a superconducting tape to be tested, comprising a skeleton support and a vacuum chamber (1) consisting of an upper and lower layer, an adjustable tension component (2) passing through the upper and lower layers of the skeleton support and the vacuum chamber (1) and extending downward to an ultra-low temperature test layer, a strip clamping tool (3) fixedly connected to the bottom end of the adjustable tension component (2), and a current lead terminal (4) arranged on the superconducting tape to be tested; the skeleton support and the vacuum chamber (1) have an upper layer in a room temperature environment and are used for the adjustable tension component (2) to adjust stress online in a room temperature environment; the lower layer is in a vacuum environment and is provided with a vacuum chamber, which is used to isolate heat; the strip clamping tool (3) comprises a fixed clamping component (3-1), a replaceable clamping component (3-2), and a plurality of fixed clamping components (3-3). The replaceable clamping component comprises a replaceable bending tool clamping component (3-2) and a replaceable stretching and torsion tool clamping component (3-3). Through the combination of different clamping components, various deformation modes of stretching, bending and torsion of the strip can be realized; the replaceable stretching and torsion tool clamping component (3-3) adopts an axisymmetric device capable of eliminating non-reference stress interference. When the axisymmetric device performs a stretching or torsion strip test, two strips are respectively fixed on the test device, one of which is a reference strip used to test the reference stress, and the other is a non-reference strip used to test the superimposed stress. The adjustable tension component (2) comprises three layers: an upper layer, a middle layer and a lower layer. The upper layer corresponds to the room temperature environment of the skeleton support and the vacuum chamber (1), and the middle layer corresponds to the vacuum environment of the skeleton support and the vacuum chamber (1). The upper layer is provided with an adjusting nut (2-2) and a pressure sensor (2-3), and the middle layer is provided with a metal bellows (2-4). The upper layer and the middle layer share a stainless steel adjustable screw (2-1), and the lower layer is provided with a G10 pull rod (2-5). The adjustable tension component (2) realizes stress loading on the strip by rotating the adjusting nut (2-2) to change the stroke of the adjustable screw (2-1), and obtains the tension borne by the strip by reading the change of the pressure sensor (2-3), wherein the pressure borne by the strip is δ=F / A, wherein δ is stress; F: tension; A: cross-sectional area of ​​the strip; the non-reference stress interference includes the interference of thermal stress; The third layer of the adjustable tension component (2) is provided with three G10 (2-5) pull rods, the middle one is G10 pull rod three (2-5-3), and the two sides are G10 pull rod one (2-5-1) and G10 pull rod two (2-5-2). The G10 pull rod one (2-5-1) and G10 pull rod two (2-5-2) on both sides are connected to the stainless steel adjustable screw rod (2-1), and the middle G10 pull rod three (2-5-3) is fixed and not connected to the stainless steel adjustable screw rod (2-1). When the adjusting nut (2-2) is rotated, the G10 pull rod one (2-5-1) and G10 pull rod two (2-5-2) move up and down with the metal bellows (2-4). Since the strip is fixed at the ends of the G10 pull rod one (2-5-1) and G10 pull rod two (2-5-2), the strip also moves up and down with the metal bellows (2-4); The fixed clamping component (3-1) is fixedly connected to the G10 pull rod 1 (2-5-1) and the G10 pull rod 2 (2-5-2) respectively by bolts, and moves up and down together with the adjustable tension rod during the stress loading process; The replaceable bending tool clamping component (3-2) comprises a cylindrical support (3-2-1) and supporting cylinders with different curvatures (3-2-2), wherein the cylindrical support (3-2-1) is fixed on a G10 pull rod (2-5-3), and supporting cylinders with different curvatures (3-2-2) are placed on the cylindrical support (3-2-1). The strip passes around the supporting cylinders with different curvatures (3-2-2) to simulate the critical characteristics test under different bending radii. The test method comprises the following steps: Step 1: Select multiple deformation modes of the superconducting tape to be tested, wherein the multiple deformation modes include bending deformation mode, stretching deformation mode and twisting deformation mode; Step 2: If the bending deformation mode is selected, the curvature specification of the replaceable bending tool clamping component (3-2) is further selected, and the replaceable bending tool clamping component (3-2) that meets the current specification is fixed at the lower end of the G10 pull rod three (2-5-3), and a whole strip of appropriate length is selected for critical testing of bending deformation, and online stress adjustment is performed; if the stretching and torsion deformation mode is selected, the stretching and torsion angle specifications of the replaceable stretching and torsion tool clamping component (3-3) are further selected, and the replaceable stretching and torsion tool clamping component (3-3) that meets the angle specifications is fixed at the lower end of the G10 pull rod three (2-5-3), and two strips of appropriate length are selected for critical testing of stretching and torsion deformation, one of which is a reference strip used to test the reference stress, and the other is a non-reference strip used to test the superimposed stress, and online stress adjustment is performed.

2. A method for testing critical characteristics of a superconducting tape in a multi-deformation mode according to claim 1, characterized in that: The critical test of bending deformation is carried out as follows: 1) Selecting a replaceable bending fixture clamping component (3-2), and selecting supporting cylinders (3-2-2) with different curvatures and suitable bending diameters, wherein the curvatures of the supporting cylinders (3-2-2) with different curvatures include 5 mm, 10 mm, 12 mm, 15 mm, and 20 mm; 2) Cut a superconducting tape with a length of 24~28cm, wipe the surface of the superconducting tape with alcohol, non-woven fabric and other materials, paste the low-temperature strain gauge at the appropriate position, and weld the voltage lead; 3) Fixing the pre-treated strip material on the fixed clamping component (3-1) and the replaceable bending tool clamping component (3-2); 4) Connect the critical characteristic test device to the cryostat, lead out the current lead, strain test lead, voltage lead, and evacuate the critical characteristic test device and the cryostat; 5) When the vacuum is better than 5×10-3Pa, turn on the refrigerator to cool down, and use the heating plate to stabilize the refrigerator at a constant temperature, load the critical current and stress of the superconducting tape, and record the voltage signal on the superconducting tape in real time to determine whether it is quenched; 6) Until the superconducting tape quenches, record the current I, voltage V, tension, and strain to obtain the superconducting critical characteristic parameters, then reheat and complete the test; 7) Adjust the bending stress online: read the data on the strain gauge. If the stress does not meet the requirement, manually adjust the adjusting nut (2-2) until the bending stress reaches the set requirement.

3. A method for testing critical characteristics of a superconducting tape in a multi-deformation mode according to claim 1, characterized in that: The critical test of tensile and torsional deformation is carried out as follows: 1) Select a replaceable stretching and torsion tooling clamping component (3-3), and select a stretching and torsion pressing block 1 (3-3-1) with a suitable angle, wherein the angle of the stretching and torsion pressing block 1 includes 0 degrees, 5 degrees, 10 degrees, 15 degrees, and 20 degrees; 2) Cut two superconducting tapes with a length of 12~16cm, wipe the surface of the superconducting tapes with alcohol, non-woven fabric and other materials, paste low-temperature strain gauges at appropriate positions, and weld voltage leads; 3) respectively fixing the two pre-treated strips on the respective fixing clamping components (3-1), the tensile torsion pressing block 1 (3-3-1), and the tensile torsion pressing block 2 (3-3-2) on both sides of the axis in an axisymmetric manner; 4) connecting the critical characteristics test device to the cryostat, connecting the lead-out current lead and the voltage lead to one of the superconducting tapes, and evacuating the critical characteristics test device and the cryostat; 5) When the vacuum is better than 5×10-3Pa, turn on the refrigerator to cool down, and use the heating plate to stabilize the refrigerator at a constant temperature, load the critical current and stress of the superconducting tape, and record the voltage signal on the superconducting tape in real time to determine whether it is quenched; 6) During the critical current loading process of the tape, the stress difference between the superconducting tape without current loading and the superconducting tape with current loading is compared and observed. The difference is mainly caused by the disturbance of thermal stress. 7) Adjust the tensile and torsional stress online: read the data on the strain gauge on each strip. If the tensile and torsional stresses do not meet the requirements, manually adjust the adjusting nut (2-2) until the tensile and torsional stresses meet the set requirements; 8) Until the superconducting tape quenches, record the current I, voltage V, tension, and strain to obtain the superconducting critical characteristic parameters, then reheat and complete the test.

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