A tensile component for testing mechanical properties of materials

Abstract

The present invention discloses a tensile assembly for testing the mechanical properties of materials, comprising a pull rod, a first thermal barrier, a first joint, a connecting structure, a second joint, a clamp, and a temperature sensor. The first thermal barrier is sleeved on the end of the pull rod and connected to the first joint. The end of the first joint away from the pull rod is connected to the second joint for connecting to a sample to be tested via a connecting structure. The second joint is provided with a clamp for connecting to a refrigerator, and the clamp is provided with a temperature sensor. The connecting structure comprises a connector, a second thermal barrier, and a pin. The advantage of the present invention is that, by calibrating the position of the temperature sensor, the temperature sensor on the tensile assembly can accurately measure the temperature of the sample to be tested even if it is not provided on the sample to be tested, thereby reducing the influence on the mechanical properties of the sample to be tested during the test, and thus being able to accurately measure the mechanical properties of the sample to be tested.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical properties, and in particular to a tensile component for testing the mechanical properties of materials. Background Art

[0002] At present, in all devices that meet the requirements of mechanical property testing of engineering materials, the temperature measurement of the tensile component sample rod requires increasingly higher accuracy, and precise temperature control must be met during low-temperature testing. Therefore, the error between the temperature of the sample rod and the temperature of the sensor is required to be smaller and smaller, that is, the temperature of the temperature sensor can be considered to be the temperature of the sample being tested.

[0003] The Chinese invention patent document with publication number CN109297804A discloses a liquid hydrogen temperature zone material mechanical testing platform based on a low-temperature refrigerator and a refrigerant cycle, which is used to realize isothermal tension, compression, bending, shear, fatigue, fracture toughness and other mechanical property tests of materials in a large temperature range from liquid hydrogen temperature to room temperature. Paragraph 0029 of the specification describes that "three thermometers 41 are respectively arranged at the upper end, middle part and lower end of the test section of the test sample 23 to be tested, for monitoring the temperature of the test section of the test sample 23 to be tested." Although setting the thermometer on the sample to be tested can improve the accuracy of temperature measurement, it has a certain impact on the mechanical properties of the sample to be tested, resulting in the inability to accurately measure the mechanical properties of the sample to be tested. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to provide a stretching assembly that can accurately measure the mechanical properties of a sample to be tested.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A tensile assembly for testing the mechanical properties of materials, comprising a pull rod, a first thermal barrier, a first joint, a connecting structure, a second joint, a clamp, and a temperature sensor. The first thermal barrier is sleeved on the end of the pull rod and connected to the first joint. The end of the first joint, remote from the pull rod, is connected to the second joint for connecting to a sample to be tested via the connecting structure. The second joint is provided with a clamp for connecting to a refrigerator, and the clamp is provided with a temperature sensor.

[0007] The connection structure includes a connecting piece, a second thermal barrier and a pin. One end of the connecting piece is connected to the first joint, and the other end of the connecting piece is sleeved with the second thermal barrier and inserted into the second joint. The pin passes through the second joint, the second thermal barrier and the connecting piece sleeved inside the second thermal barrier, so that the connecting piece is connected to the second joint.

[0008] The stretching assembly is provided with a first thermal barrier and a second thermal insulation section, so that the temperature of the sample to be tested can be accurately measured even if the temperature sensor is not provided on the sample to be tested, thereby reducing the impact on the mechanical properties of the sample to be tested during the test, and thus being able to accurately measure the mechanical properties of the sample to be tested.

[0009] Preferably, the pull rod is further provided with a copper wire for connecting to a cold head of a refrigerator.

[0010] Preferably, the distance from the copper to the sample to be tested is 1 / 3 of the distance to the end of the pull rod at room temperature.

[0011] Preferably, the first thermal barrier is a 70K thermal barrier made of G10.

[0012] Preferably, there is a gap between the pull rod and the connecting piece in the first joint; heat transfer is only carried out by thermal radiation, and the thermal conductivity effect is poor. If the cavity is evacuated, the air in this non-contact area is further extracted, the thermal radiation is further reduced, and the thermal isolation effect is significant.

[0013] Preferably, the second thermal barrier is a 4K thermal barrier made of G10.

[0014] Preferably, a third thermal barrier is further provided on the end surface of the first joint close to the second joint, and the third thermal barrier is a 70K thermal barrier made of G10.

[0015] Preferably, the connecting member is further provided with a ballast sheet for pressing the third thermal barrier.

[0016] Preferably, a fourth thermal barrier is provided on the end face of the second joint close to the first joint, and the fourth thermal barrier is a 4K thermal barrier made of G10.

[0017] Preferably, the clamp includes a left clamp and a right clamp, the left clamp and the right clamp are symmetrically arranged, and a temperature sensor is fixed on each of the left clamp and the right clamp.

[0018] By clasping the end of the second joint with two symmetrical left and right hoops, heat conduction can be improved while preventing axial displacement caused by stretching, which may lead to inaccurate temperature measurement by the temperature sensor.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The stretching assembly is provided with a first thermal barrier and a second thermal insulation section, so that the temperature of the sample to be tested can be accurately measured even if the temperature sensor is not provided on the sample to be tested, thereby reducing the influence on the mechanical properties of the sample to be tested during the test, and thus being able to accurately measure the mechanical properties of the sample to be tested.

[0021] 2. There is a gap between the pull rod and the connector in the first joint, and heat transfer is only done by thermal radiation, which has a poor thermal conductivity. If the cavity is evacuated, the air in this non-contact area will be further evacuated, the thermal radiation will be further reduced, and the thermal isolation effect will be significant.

[0022] 3. By using two symmetrical left and right clamps to hold the end of the second joint, heat conduction can be improved while preventing axial displacement caused by stretching, which may lead to inaccurate temperature measurement by the temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a tensile assembly for testing the mechanical properties of a material according to an embodiment of the present invention;

[0024] Figure 2 A partial cross-sectional view of an embodiment of the present invention;

[0025] Figure 3 This is a temperature distribution diagram of the first connector and the connector according to an embodiment of the present invention;

[0026] Figure 4 This is a temperature distribution diagram of the second connector and the connector according to an embodiment of the present invention;

[0027] Figure 5 This is a temperature distribution diagram of the clamp in a low-temperature state according to an embodiment of the present invention;

[0028] Figure 6 This is a temperature distribution diagram of the clamp in the high temperature state according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] To facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described with reference to the accompanying drawings.

[0030] In this application, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0031] In this application, unless otherwise expressly specified or limited, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly indicate the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise expressly specified or limited.

[0032] See Figure 1 and Figure 2 This embodiment discloses a tensile assembly for testing the mechanical properties of materials, including a pull rod 1, a first thermal barrier 2, a first joint 3, a copper rod 4, a connecting structure 5, a second joint 6, a clamp 7, a welding seat 8 and a temperature sensor 9.

[0033] The end of the pull rod 1 is sleeved with a first thermal barrier 2 and movably connected to the first joint 3. The first thermal barrier 2 is a 70K thermal barrier made of G10, which effectively blocks the heat conduction from the normal temperature end of the pull rod 1 to the first joint 3. The heat blocked by the first thermal barrier 2 is conducted to the low temperature side through the first joint 3, and the isolation effect is obvious.

[0034] The pull rod 1 is also provided with a copper soft 4 connected to the cold head of the refrigerator. In this embodiment, the temperature of the copper soft 4 is 60-70K, and the distance from the copper soft 4 to the sample to be tested 10 is 1 / 3 of the distance to the room temperature end of the pull rod 1, which is more effective for cold isolation.

[0035] The end of the first joint 3 away from the pull rod 1 is connected to the second joint 6 for connecting to the sample 10 to be tested via a connecting structure 5. Specifically, the connecting structure 5 includes a connector 51, a second thermal barrier 52, a pin 53, a third thermal barrier 54, a ballast plate 55, and a fourth thermal barrier 56. One end of the connector 51 is threadedly connected to the first joint 3. There is a gap between the pull rod 1 and the connector 51 in the first joint 3. At this time, heat transfer is only carried out by thermal radiation, which has a poor thermal conductivity. If the cavity is evacuated, the air in this non-contact area is further evacuated, and the thermal radiation is further reduced, resulting in a significant thermal isolation effect. The other end of the connector 51 is sleeved with the second thermal barrier 52 and inserted into the second joint 6. The pin 53 passes through the second joint 6, the second thermal barrier 52, and the connector 51 sleeved inside the second thermal barrier 52, so that the connector 51 and the second joint 6 are movably connected. The second thermal barrier 52 is a 4K thermal barrier made of G10, which effectively isolates the heat transfer from the connector 51 to the second joint 6.

[0036] A third thermal barrier 54 is also provided on the end face of the first joint 3 near the second joint 6. The third thermal barrier 54 is a 70K thermal barrier made of G10. The third thermal barrier 54 further isolates the first joint 3 from the initial temperature isolation, thereby reducing heat radiation from the first joint 3 to the second joint 6. Furthermore, a ballast sheet 55 is provided on the connector 51 for compressing the third thermal barrier 54, thereby securing the third thermal barrier 54 and ensuring contact with the end face of the first joint 3.

[0037] A fourth thermal barrier 55 is provided on the end face of the second joint 6 close to the first joint 3. The fourth thermal barrier 55 is a 4K thermal barrier made of G10, which reduces the heat radiation of the first joint 3 and the connecting piece 51 to the second joint 6, thereby isolating the cold energy transferred from the sample to be tested 10 to the second joint 6, so that the second joint 6 transfers cold energy only through the pin 53, and the cold energy transferred by the pin 53 is small and can be ignored, thereby ensuring that the temperature on the second joint 6 is the same as the temperature on the sample to be tested 10.

[0038] Furthermore, the connecting piece 51 and the ballast plate 55 are both made of titanium alloy.

[0039] Furthermore, the second joint 6 is made of beryllium bronze, so that the second joint 6 has high tensile strength and good thermal conductivity.

[0040] Furthermore, the sample to be tested 10 is connected to the internal thread of the second joint 6 through an external thread, the thread size is M20, and the cooling capacity is transferred through the thread contact. Moreover, after calculation and analysis, the maximum diameter of the sample to be tested 10 can be any value between (0, 20] mm, the length can be determined according to the size of the vacuum chamber, and the diameter can be adjusted arbitrarily to meet the tensile force value of 50-100 kN.

[0041] The second joint 6 is provided with a clamp 7 for connecting to the refrigerator, and the clamp 7 includes a left clamp 71 and a right clamp 72. The left clamp 71 and the right clamp 72 are symmetrically arranged, and the center positions of the left clamp 71 and the right clamp 72 are silver-brazed with a welding seat 8, and the temperature sensor 9 is fixed on the welding seat 8; the temperature on the second joint 6 is transmitted by the clamp 7, so that the temperatures of the clamp 7, the second joint 6 and the sample to be tested 10 are the same, so that the temperature measured by the temperature sensor 9 on the clamp 7 is the temperature of the sample to be tested 100.

[0042] In this embodiment, the first thermal isolation is achieved by the copper soft 4 on the pull rod 1, the second thermal isolation is achieved by the first thermal isolation 2, and the third thermal isolation is achieved by the second thermal isolation 52, so that the temperature transmitted from the pull rod 1 to the second joint 6 is the lowest, and thus the second joint 6 will not transmit a temperature higher than the target temperature to the clamp 7. Through position calibration, the temperature of the sensor 9 is ensured to be consistent with the temperature of the sample to be measured 10, thereby ensuring the accuracy of the temperature sensor 9 in measuring the temperature of the sample to be measured 10.

[0043] By holding the end of the second joint 6 with two symmetrical left and right clamps 71 and 72, better heat conduction can be achieved while preventing axial displacement caused by stretching, which may lead to inaccurate temperature measurement by the temperature sensor 9.

[0044] In this embodiment, the temperature sensor 9 is a DT670 temperature sensor, which adopts CU package and is fixed to the pure copper welding seat 8 with M3 screws to collect the temperature of the second joint 6, thereby realizing the temperature collection of the sample 10 to be tested.

[0045] The temperature sensor 9 on the stretching assembly is not set on the sample 10 to be tested and can also accurately measure the temperature of the sample 10 to be tested, reducing the impact on the mechanical properties of the sample 10 to be tested during the test, and thus can accurately measure the mechanical properties of the sample 10 to be tested.

[0046] For details, see Figure 3 The leftmost end frame of the pull rod 1 is loaded with a 300K boundary, the copper soft 4 is a 70K temperature boundary, and the cold head of the refrigerator connected to the clamp 7 is loaded with a 4K boundary condition. The results show that the temperature on the right side has a significant temperature difference with the middle part, indicating that titanium alloy has good thermal insulation ability and the material selection is appropriate.

[0047] See Figure 4 The leftmost end frame of the pull rod 1 is loaded with a 300K boundary condition, the copper soft 4 is loaded with a 70K temperature boundary condition, and the cold head of the refrigerator connected to the clamp 7 is loaded with a 4K boundary condition. The temperature distribution of the outer surface of the second thermal barrier 52 is almost the same, which shows that the thermal insulation effect is significant.

[0048] See Figure 5 It can be seen that the temperature of the measuring point is about 4.95K, and the temperature of the sample 10 to be measured is about 4.94K. The temperature error between the two is 0.01K. The accuracy is 0.2% at this time, which is also the accuracy value of the temperature measuring instrument. Therefore, the temperature of the measuring point can be regarded as the temperature value of the sample 10 to be measured, and the lowest temperature is about 5K.

[0049] See Figure 6The leftmost end of tie rod 1 is subjected to a 300K boundary condition, copper 4 to a 70K boundary condition, and the upper portion of the cold plate of the refrigerator head connected to clamp 7 is subjected to a 12W heat flux boundary condition. As can be seen, the test point temperature is 469.88K, while the temperature of sample 10 is 469.97K, with a temperature difference of 0.09K and a relative error of 0.02%, representing near-identical accuracy. This high-temperature simulation verifies that the position of temperature sensor 9 is equally accurate at high temperatures, with even higher accuracy. Theoretically, this device can test even higher temperatures. Due to the stable material strength of G10 at 120°C, high-temperature measurements of approximately 400K are possible.

[0050] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description. It is intended that all variations within the meaning and range of equivalents of the claims be embraced herein, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0051] The above-mentioned embodiments merely represent the implementation methods of the invention. The protection scope of the present invention is not limited to the above-mentioned embodiments. For those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention, which all fall within the protection scope of the present invention.

Claims

1. A tensile assembly for testing the mechanical properties of materials, characterized by: The device comprises a pull rod, a first thermal barrier, a first joint, a connecting structure, a second joint, a clamp, and a temperature sensor. The first thermal barrier is sleeved on the end of the pull rod and connected to the first joint. The end of the first joint away from the pull rod is connected to the second joint for connecting to the sample to be tested through the connecting structure. The second joint is provided with a clamp for connecting to a refrigerator, and the clamp is provided with a temperature sensor. The connection structure includes a connecting piece, a second thermal barrier and a pin. One end of the connecting piece is connected to the first joint, and the other end of the connecting piece is sleeved with the second thermal barrier and inserted into the second joint. The pin passes through the second joint, the second thermal barrier and the connecting piece sleeved inside the second thermal barrier, so that the connecting piece is connected to the second joint.

2. The tensile assembly for testing the mechanical properties of materials according to claim 1, characterized in that: The pull rod is also provided with a copper rod connected to the cold head of the refrigerator.

3. The tensile assembly for testing mechanical properties of materials according to claim 2, characterized in that: The distance from the copper rod to the sample to be tested is 1 / 3 of the distance from the copper rod to the end of the pull rod at room temperature.

4. The tensile assembly for testing the mechanical properties of materials according to claim 1, characterized in that: The first thermal barrier is a 70K thermal barrier made of G10.

5. The tensile assembly for testing mechanical properties of materials according to claim 1, characterized in that: There is a gap between the pull rod and the connecting piece in the first joint.

6. The tensile assembly for testing mechanical properties of materials according to claim 1, characterized in that: The second thermal barrier is a 4K thermal barrier made of G10.

7. The tensile assembly for testing mechanical properties of materials according to claim 1, characterized in that: A third thermal barrier is further provided on the end surface of the first joint close to the second joint. The third thermal barrier is a 70K thermal barrier made of G10.

8. The tensile assembly for testing mechanical properties of materials according to claim 7, characterized in that: The connecting piece is also provided with a ballast sheet for pressing the third thermal barrier.

9. The tensile assembly for testing mechanical properties of materials according to claim 1, characterized in that: A fourth thermal barrier is provided on the end surface of the second joint close to the first joint. The fourth thermal barrier is a 4K thermal barrier made of G10.

10. The tensile assembly for testing mechanical properties of materials according to claim 1, characterized in that: The clamp comprises a left clamp and a right clamp, the left clamp and the right clamp are symmetrically arranged, and temperature sensors are fixed on both the left clamp and the right clamp.

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