A buckling-restrained device for axial tension-compression fatigue test of metal sheet

Abstract

The present application relates to the technical field of metal material fatigue test, and provides a buckling prevention device for axial tension-compression fatigue test of metal sheet, which comprises a sample and two groups of clamping plates clamped on the front and back surfaces of the sample respectively, each group of clamping plates comprises a long clamping plate and a short clamping plate, the long clamping plate comprises a long wing plate and a long web, and the short clamping plate comprises a short wing plate and a short web, the free end of the long web is provided with a bearing step, the short web is supported on the bearing step, a limiting part is arranged above the bearing step, a limiting groove is formed in the short web and matched with the limiting part, the limiting part is accommodated in the limiting groove, and the length of the long web is not less than the length of the deformation part. The structure of the long clamping plate and the short clamping plate is improved, so that a complementary meshing structure is formed between the long clamping plate and the short clamping plate, the length of the long web of the long clamping plate is limited to be not less than the length of the deformation part of the sample, and the deformation part of the sample can be prevented from being abraded by the buckling prevention device in the actual test process.

Description

Technical Field

[0001] This invention relates to the field of fatigue testing technology for metallic materials, and more specifically, to an anti-buckling device for axial tensile and compressive fatigue testing of thin metal plates. Background Technology

[0002] In recent years, with the rapid development of transportation, aerospace and other fields, thin metal sheets have been widely used as an important raw material in the manufacture of various vehicle bodies. However, thin metal sheets used for fatigue testing have small thickness dimensions, a large slenderness ratio, and low stiffness. When subjected to tensile and compressive cyclic loads, they are prone to lateral buckling instability in the thickness direction. Under continuous cyclic loads, the specimen will exhibit buckling deformation along the thickness direction, leading to specimen failure and affecting the test results and safety.

[0003] To address this issue, the standard GB / T 26077-2010, "Methods for Controlling Axial Strain in Fatigue Testing of Metallic Materials," proposes a buckling-resistance device. This device primarily consists of two clamping plates attached and held against the specimen on both sides along its thickness direction, secured with bolts. Lubrication is achieved between the clamping plates and the specimen using a polytetrafluoroethylene film or boron nitride powder dry lubricant. During the test, this device constrains the specimen's deformation along its thickness direction, thus preventing buckling. However, this buckling-resistance device does not release the axial constraint of the specimen during the test. Furthermore, when tightening the bolts, excessive torque increases the friction between the device and the specimen, hindering axial deformation and introducing an error between the axial loading force and the actual axial force on the specimen, affecting the accuracy of the test results. Conversely, insufficient bolt torque reduces friction, making the device prone to relative sliding and posing a safety hazard.

[0004] A search revealed Chinese patent document CN205749099U, which discloses a buckling-resistance device for low-cycle fatigue testing of cold-rolled thin plates. This device, by designing the two side clamps as separate structures containing long and short buckling-resistance plates, releases the constraint of the buckling-resistance device on the axial displacement of the specimen, thus reducing the influence of friction between the buckling-resistance device and the specimen on the test results. However, in the aforementioned patent document, the connection point between the long and short buckling-resistance plates is located in the deformed part of the middle of the specimen. During the contact process between the long and short buckling-resistance plates and the fatigue specimen, their edges are prone to wear and forming wear points at the weakest part of the smallest cross-section in the middle of the specimen, further inducing the formation of fatigue crack initiation points and reducing the specimen life. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-buckling device for axial tensile and compressive fatigue testing of thin metal plates, so as to overcome at least the technical problem that existing anti-buckling devices that can release the axial constraint of the specimen are prone to causing wear in the middle of the specimen to form wear points, thereby inducing the formation of fatigue crack initiation.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A buckling-resistant device for axial tensile and compressive fatigue testing of thin metal plates includes a specimen and two sets of clamping plates. The specimen includes a first clamping part, a deformation part, and a second clamping part along its length. The two sets of clamping plates are respectively clamped on the front and back sides of the specimen. Each clamping plate includes a long clamping plate and a short clamping plate. Both the long and short clamping plates have a T-shaped structure. The long clamping plate includes a long wing plate and a long web plate. The short clamping plate includes a short wing plate and a short web plate. The long wing plate is clamped in the first clamping part, the short wing plate is clamped in the second clamping part, and the long web plate is clamped in the deformation part.

[0008] The free end of the long web is provided with a bearing step, the short web is supported on the bearing step, a limiting part is provided above the bearing step, the limiting part extends along the length direction of the long web, a limiting groove adapted to the limiting part is opened on the short web, the limiting part is accommodated in the limiting groove, and the length of the long web is not less than the length of the deformable part.

[0009] In some possible embodiments, the long wing plate has a first fixing hole at both ends, and the short wing plate has an extension at both ends. The extension extends in the direction of the long wing plate and has a plurality of second fixing holes. The plurality of second fixing holes are arranged sequentially along the length of the extension. Fastening bolts are provided in both the first fixing holes and the second fixing holes.

[0010] In some possible embodiments, the number of the second fixing holes is two.

[0011] In some possible embodiments, gaps are reserved between the free ends of the short web and the long web, and between the free end of the limiting portion and the innermost inner wall of the limiting groove.

[0012] In some possible embodiments, the width of the long web is not greater than the minimum width of the deformed portion.

[0013] In some possible embodiments, the bottom surface of the long web is provided with a mounting groove, the mounting groove extends along the length of the long web, and a lubricating block is embedded in the mounting groove.

[0014] In some possible embodiments, the mounting groove has a T-shaped structure, the lubrication block includes an elastic part and a lubrication part, the elastic part is adapted to the mounting groove and embedded in the mounting groove, and the lubrication part is disposed at the bottom of the elastic part.

[0015] In some possible embodiments, the elastic part is made of polyester rubber and the lubricating part is made of polytetrafluoroethylene.

[0016] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0017] 1. Based on existing buckling protection devices, this invention improves the structure of the long and short clamping plates and optimizes the connection between them, creating a complementary meshing structure. Simultaneously, the length of the long web of the long clamping plate is limited to be no less than the length of the deformed portion of the specimen. This prevents the buckling protection device from eroding the deformed portion of the specimen during actual testing, thereby minimizing the generation of fatigue crack initiation, ensuring the continuous and reliable conduct of the test, and effectively improving the accuracy of the test results.

[0018] 2. The present invention improves the locking effect when the short clamping plates of the two sets of clamping plates are locked with fastening bolts by setting an extension portion extending in the direction of the long clamping plate at the end of the short wing plate and opening a corresponding second fixing hole on the extension portion, and can ensure that the clamping force applied to the deformed part of the specimen by the anti-buckling device is large enough, thereby further improving the stability of the specimen during tensile and compressive fatigue tests.

[0019] 3. By adding a thicker lubricating block as the lubrication structure of the anti-buckling device, the present invention can avoid repeatedly replacing the lubrication structure during multiple tensile and compressive fatigue tests, thus improving the practicality of the anti-buckling device. At the same time, by further improving the structure of the lubricating block, the lubrication part can be kept in contact with the surface of the sample as much as possible during the test, avoiding the failure of lubrication. While ensuring the smooth conduct of the test, it can also improve the accuracy of the final test results to a certain extent. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the anti-buckling device provided in Embodiment 1 of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of the sample provided in Embodiment 1 of the present invention;

[0022] Figure 3 This is a schematic diagram of the clamping plate assembly provided in Embodiment 1 of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of the long clamping plate provided in Embodiment 1 of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of the short clamp provided in Embodiment 1 of the present invention;

[0025] Figure 6 This is a schematic diagram of the long clamping plate and lubrication block provided in Embodiment 2 of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of the long clamping plate provided in Embodiment 2 of the present invention;

[0027] Figure 8 This is a schematic diagram of the structure of the lubricating block provided in Embodiment 2 of the present invention.

[0028] Icons: 10-Sample, 11-First clamping part, 12-Deformable part, 13-Second clamping part, 20-Clamping plate assembly, 21-Long clamping plate, 211-Long wing plate, 211a-First fixing hole, 212-Long web plate, 212a-Bearing step, 212b-Limiting part, 212c-Mounting groove, 22-Short clamping plate, 221-Short wing plate, 221a-Extension part, 221b-Second fixing hole, 222-Short web plate, 222a-Limiting groove, 30-Fasting bolt, 40-Lubricating block, 41-Elastic part, 42-Lubricating part. Detailed Implementation

[0029] Example 1

[0030] Please refer to Figures 1 to 5 This embodiment provides a buckling protection device for axial tensile and compressive fatigue testing of thin metal plates, which at least overcomes the technical problem that existing buckling protection devices that can release the axial constraint of the specimen 10 are prone to causing wear in the middle of the specimen 10 to form a wear point, thereby inducing the formation of fatigue crack initiation. Specifically, the buckling protection device includes a specimen 10 and two sets of clamping plates 20.

[0031] In this embodiment, combined with Figure 2 The specimen 10 used for tensile and compressive fatigue testing includes a first clamping part 11, a deformation part 12, and a second clamping part 13 along its length. Specifically, the deformation part 12 of the specimen 10 is an arc-shaped structure with the side edges recessed towards the center. In actual implementation, the first clamping part 11, the deformation part 12, and the second clamping part 13 are integrally formed to ensure the integrity of the specimen 10 structure.

[0032] In this embodiment, combined with Figure 1 As shown, two sets of clamping plates 20 are respectively clamped on the front and back sides of the sample 10 to clamp and fix the sample 10, thereby facilitating subsequent tensile and compressive fatigue tests.

[0033] Specifically, such as Figure 1 and Figure 3 As shown, each clamping plate group 20 includes a long clamping plate 21 and a short clamping plate 22, and both the long clamping plate 21 and the short clamping plate 22 have a T-shaped structure. Specifically, the long clamping plate 21 includes a long wing plate 211 and a long web plate 212, and the short clamping plate 22 includes a short wing plate 221 and a short web plate 222. When the clamping plate group 20 clamps the sample 10, the long wing plate 211 is clamped in the first clamping part 11, the short wing plate 221 is clamped in the second clamping part 13, and the long web plate 212 is clamped in the deformation part 12.

[0034] At this point, in order to reduce the wear caused by the clamping plate assembly 20 on the deformed portion 12 in the middle of the sample 10, and to avoid the formation of wear points in the deformed portion 12 to induce fatigue crack initiation, combined with Figure 4 As shown in the embodiment, a bearing step 212a is provided at the free end of the long web 212 (i.e., the end of the long web 212 away from the long wing 211). At this time, as... Figure 1 or Figure 3 As shown, the short web 222 is supported on the supporting step 212a. A limiting part 212b is provided above the supporting step 212a. The limiting part 212b extends along the length direction of the long web 212 and has a pre-reserved gap with the supporting step 212a. At the same time, combined with Figure 5 As shown, the short web 222 has a limiting groove 222a that matches the limiting part 212b. When the sample 10 is clamped by the clamping plate assembly 20, as... Figure 1 or Figure 3 As shown, the limiting part 212b of the long web 212 is housed in the limiting groove 222a of the short web 222, and the length of the long web 212 is not less than the length of the deformable part 12, and the width of the long web 212 is not greater than the minimum width of the center of the deformable part 12.

[0035] With this configuration, since the length of the long web 212 is not less than the length of the deformable part 12, and the short web 222 is supported on the bearing step 212a of the long web 212, when the sample 10 is clamped by the two clamping plate groups 20, a complementary meshing structure is formed between the long web 212 of the long clamping plate 21 and the short web 222 of the short clamping plate 22. At this time, a gap is reserved between the free end of the short web 222 and the free end of the long web 212, and the free end of the limiting part 212b and the limiting groove are connected. A gap is also reserved between the innermost inner walls of 222a. The long web 212 and the short web 222 are connected by a complementary meshing structure. While releasing the axial constraint of the specimen 10, the bending resistance of the middle part of the buckling-resistance device is good. Since only the long web 212 is clamped in the deformed part 12 of the specimen 10, the clamping plate group 20 is effectively prevented from causing abrasion to the deformed part 12 of the specimen 10, and the influence of the buckling-resistance device on the specimen 10 during tensile and compressive fatigue tests is reduced.

[0036] Based on this, in order to reliably clamp and fix the sample 10 using two sets of clamping plates 20, for each set of clamping plates 20, combined with Figure 1 , Figure 4 and Figure 5 As shown, both ends of the long wing plate 211 of the long clamping plate 21 are provided with first fixing holes 211a, and fastening bolts 30 are provided in the first fixing holes 211a. At the same time, both ends of the short wing plate 221 are provided with extensions 221a, which extend in the direction of the long wing plate 211. Multiple second fixing holes 221b are provided on the extensions 221a. The multiple second fixing holes 221b are arranged sequentially along the length of the extensions 221a. For example, there are two second fixing holes 221b on the extensions 221a, and fastening bolts 30 are provided in both second fixing holes 221b.

[0037] With this configuration, when using the anti-buckling device, such as Figure 1 As shown, two sets of clamping plates 20 are respectively set on the front and back sides of the sample 10, and the long clamping plate 21 and the short clamping plate 22 in the two sets of clamping plates 20 are arranged in a mirror symmetrical manner. At this time, for a single set of clamping plates 20, the short web plate 222 is supported on the supporting step 212a of the long web plate 212, and the limiting part 212b on the long web plate 212 is inserted into the limiting groove 222a of the short web plate 222. In this state, gaps are reserved between the free end of the short web plate 222 and the free end of the long web plate 212, and between the free end of the limiting part 212b and the innermost inner wall of the limiting groove 222a. In this state, the sample 10 is located on the front and back sides of the sample 10. The first fixing hole 211a on the front long wing plate 211 is aligned with the corresponding first fixing hole 211a on the back long wing plate 211 of the sample 10. Correspondingly, the second fixing hole 221b on the front short wing plate 221 of the sample 10 is aligned with the corresponding second fixing hole 221b on the back short wing plate 221 of the sample 10. Then, the long wing plates 211 on both sides of the sample 10 and the short wing plates 221 on both sides of the sample 10 can be reliably connected by the fastening bolts 30 to lock the two sets of clamping plate assemblies 20, thereby achieving reliable clamping and fixing of the sample 10.

[0038] It should be noted that by providing an extension 221a extending toward the direction of the long wing 211 at the end of the short wing 221, and also opening a second fixing hole 221b on the extension 221a, a certain torque can be provided between the short clamps 22 in the two clamping groups 20 that are locked during locking. This improves the locking effect while ensuring that the clamping force applied by the anti-bending device to the deformed part 12 of the sample 10 is large enough.

[0039] Furthermore, considering that if the torque of the fastening bolt 30 is too large during the buckling restraint device stage, it will increase the friction between the buckling restraint device and the specimen 10, hindering the axial deformation of the specimen 10, resulting in an error between the axial force applied to the specimen 10 and the actual axial force on the specimen 10, thus affecting the accuracy of the test results. Conversely, if the torque of the fastening bolt 30 is too small, it will reduce the friction between the buckling restraint device and the specimen 10, and the buckling restraint device will easily slip relative to the specimen 10. Therefore, auxiliary tools such as torque wrenches can be used to tighten the fastening bolt 30 to adjust the torque of all the fastening bolts 30 to the same level and ensure that the torque of all the fastening bolts 30 is within a reasonable range.

[0040] In summary, this embodiment improves the structure of the long clamp 21 and short clamp 22 of the clamp group 20 based on the existing buckling protection device, and optimizes the connection method between the long clamp 21 and the short clamp 22, so that the long clamp 21 and the short clamp 22 form a complementary meshing structure. At the same time, the length of the long web 212 of the long clamp 21 is limited to not less than the length of the deformed part 12 of the specimen 10. In the actual test, the buckling protection device can avoid abrasion of the deformed part 12 of the specimen 10, thereby avoiding the generation of fatigue crack initiation, ensuring that the test can be carried out continuously and reliably, and effectively improving the accuracy of the test results.

[0041] Meanwhile, by providing an extension 221a extending toward the direction of the long wing 211 at the end of the short wing 221 and opening a corresponding second fixing hole 221b on the extension 221a, the locking effect when locking the short wing 22 of the two sets of clamping plates 20 with the fastening bolts 30 is improved, and the clamping force applied by the anti-bending device to the deformed part 12 of the specimen 10 is sufficiently large.

[0042] Example 2

[0043] Based on Example 1, in order to further reduce the friction at the contact point between the buckling restraint device and the specimen 10 during actual testing, the method adopted in standard GB / T 26077-2010 "Methods for Axial Strain Control in Fatigue Testing of Metallic Materials" is to set up a corresponding lubrication structure (e.g., using polytetrafluoroethylene film or boron nitride powder dry lubricant) at the contact point between the buckling restraint device and the specimen 10. This method is also the method commonly used in existing buckling restraint devices. The drawback of using this method to reduce the friction between the buckling restraint device and the specimen 10 is that the corresponding polytetrafluoroethylene film or other lubricating materials need to be prepared for each test. When conducting multiple tests, the lubricating materials often need to be replaced repeatedly, making the whole process rather cumbersome.

[0044] Therefore, please refer to Figures 6 to 8This embodiment further improves the lubrication structure of the anti-buckling device, so that the anti-buckling device does not need to replace the lubricating material when conducting multiple tests.

[0045] Specifically, in combination Figure 6 and Figure 7 As shown in this embodiment, an installation groove 212c is provided on the bottom surface of the long web 212 of each long clamping plate 21, and the installation groove 212c extends along the length direction of the long web 212. At this time, a lubricating block 40 is embedded in the installation groove 212c. The lubricating block 40 can be, but is not limited to, being made of polytetrafluoroethylene.

[0046] In this embodiment, the lubricating block 40, which serves as a lubrication structure, is placed on the bottom surface of the long web 212. Since the thickness of the lubricating block 40 is greater than that of a typical polytetrafluoroethylene film, it is not necessary to replace the lubricating block 40 even during multiple tensile and compressive fatigue tests, thus further improving the practicality of the anti-buckling device in actual use.

[0047] Furthermore, considering that during the actual test, the lubricating block 40 will rub against the sample 10 during axial deformation, theoretically, as the sample 10 undergoes continuous and repeated axial deformation, the lubricating block 40 will always wear out. However, since a certain torque has been applied to the fastening bolt 30 before the test begins, there may be a situation during the test where the lubricating block 40 can no longer reliably contact the sample 10 after it is worn out, which would cause the lubricating effect of the lubricating block 40 to fail, thus affecting the accuracy of the final test results.

[0048] Therefore, this embodiment further improves the installation method and structure of the lubricating block 40 so that the lubricating block 40 can still reliably contact the surface of the sample 10 after wear. Specifically, in combination with Figure 7 and Figure 8 As shown in this embodiment, the mounting groove 212c on the bottom surface of the long web 212 is configured as a T-shaped structure. In this case, the lubrication block 40 includes an elastic part 41 and a lubrication part 42. The elastic part 41 is adapted to and embedded within the mounting groove 212c. The elastic part 41 has a certain elastic deformation capability. The lubrication part 42 is located at the bottom of the elastic part 41, so that it contacts the sample 10 to provide lubrication. The lubrication part 42 can be, but is not limited to, being made of polytetrafluoroethylene (PTFE). It is understood that, based on the fact that even if wear occurs during actual testing, the wear amount of the lubrication part 42 is often small, the elastic part 41 can be, but is not limited to, being made of polyester rubber (i.e., thermoplastic polyester elastomer, TPEE). While ensuring a good service life for the elastic part 41, a certain force can be applied to the lubrication part 42 through the elastic part 41, so that the lubrication part 42 tends to move towards the surface of the sample 10.

[0049] With this setup, in actual use, the lubricating block 40 is first inserted into the mounting groove 212c on the bottom surface of the long web 212. Specifically, the elastic part 41 is inserted into the mounting groove 212c on the bottom surface of the long web 212 to limit the elastic part 41. At this time, the lubricating part 42 protrudes to the outside of the long web 212. Then, two sets of clamping plate assemblies 20 are installed on both sides of the sample 10. After the two sets of clamping plate assemblies 20 are installed in place, for a single clamping plate assembly 20, the long wing plate of the long clamping plate 21... 211 is clamped in the first clamping part 11 of the sample 10. The long web 212 of the long clamping plate 21 is clamped in the deformable part 12 of the sample 10. Specifically, the lubrication part 42 at the bottom of the long web 212 is in contact with the deformable part 12 of the sample 10. The short wing plate 221 of the short clamping plate 22 is clamped in the second clamping part 13 of the sample 10. The short web 222 of the short clamping plate 22 is supported on the supporting step 212a of the long web 212, and the limiting part 212b on the long web 212 is inserted into the limiting groove 222a of the short web 222.

[0050] Subsequently, the two sets of clamping plates 20 are locked with fastening bolts 30. During this process, as the torque applied to the fastening bolts 30 increases, the long web 212 will apply a certain pressure to the lubrication block 40. Under this pressure, the elastic part 41 located in the mounting groove 212c undergoes elastic deformation to store a certain amount of elastic force. Once the torque applied to the fastening bolts 30 reaches the predetermined value, the tensile and compressive fatigue test can begin. During the test, as the specimen 10 undergoes continuous and repeated axial deformation, the lubrication part 42 will repeatedly rub against the specimen 10. When the lubrication part 42 wears, the elastic part 41 can release a certain amount of elastic force to force the lubrication part 42 to move in the direction of the specimen 10. This ensures that the lubrication part 42 can always reliably contact the surface of the specimen 10 during the test, thereby ensuring that the lubrication part 42 can always play a good lubricating role throughout the entire test. This ensures that the test can be carried out smoothly and improves the accuracy of the final test results to a certain extent.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A buckling-resistant device for axial tensile-compression fatigue testing of thin metal plates, comprising a specimen and two sets of clamping plates, wherein the specimen includes a first clamping portion, a deformation portion, and a second clamping portion sequentially along its length, the two sets of clamping plates clamping the front and back sides of the specimen respectively, each clamping plate assembly comprising a long clamping plate and a short clamping plate, both the long and short clamping plates having a T-shaped structure, the long clamping plate comprising a long wing plate and a long web plate, the short clamping plate comprising a short wing plate and a short web plate, the long wing plate being clamped in the first clamping portion, the short wing plate being clamped in the second clamping portion, and the long web plate being clamped in the deformation portion, characterized in that... The free end of the long web is provided with a bearing step, the short web is supported on the bearing step, a limiting part is provided above the bearing step, the limiting part extends along the length direction of the long web, a limiting groove adapted to the limiting part is opened on the short web, the limiting part is accommodated in the limiting groove, and the length of the long web is not less than the length of the deformable part. When the two sets of clamping plates clamp the sample, the long web of the long clamping plate and the short web of the short clamping plate form a complementary meshing structure; a gap is reserved between the free end of the short web and the free end of the long web, and a gap is reserved between the free end of the limiting part and the innermost inner wall of the limiting groove. The bottom surface of the long web is provided with an installation groove, which extends along the length of the long web. A lubricating block is embedded in the installation groove. The installation groove has a T-shaped structure. The lubricating block includes an elastic part and a lubricating part. The elastic part is adapted to the installation groove and is embedded in the installation groove. The lubricating part is located at the bottom of the elastic part.

2. The buckling prevention device for axial tensile and compressive fatigue testing of thin metal plates according to claim 1, characterized in that, Both ends of the long wing plate are provided with first fixing holes, and both ends of the short wing plate are provided with extensions. The extensions extend in the direction of the long wing plate and are provided with multiple second fixing holes. The multiple second fixing holes are arranged sequentially along the length of the extensions. Fastening bolts are provided in both the first fixing holes and the second fixing holes.

3. The buckling prevention device for axial tensile and compressive fatigue testing of thin metal plates according to claim 2, characterized in that, The number of the second fixing holes is two.

4. The buckling prevention device for axial tensile and compressive fatigue testing of thin metal plates according to claim 1, characterized in that, Gaps are reserved between the free ends of the short web and the long web, and between the free end of the limiting part and the innermost inner wall of the limiting groove.

5. The buckling prevention device for axial tensile and compressive fatigue testing of thin metal plates according to claim 1, characterized in that, The width of the long web is not greater than the minimum width of the deformable part.

6. The buckling-resistant device for axial tensile and compressive fatigue testing of thin metal plates according to claim 1, characterized in that, The elastic part is made of polyester rubber, and the lubricating part is made of polytetrafluoroethylene.

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