Fatigue performance test device and method

Abstract

A fatigue performance test device and method. When being used for testing the tensile fatigue performance of a rubber material, the test device comprises loading frames (1), a pressing mechanism, and gaskets (3), and when being used for testing the shear fatigue performance of the rubber material, the test device comprises loading frames (1) and a pressing mechanism. During testing, the loading frames (1) are fixed by means of positioning panels (6), and after samples (5) are mounted in place, the positioning panels (6) are removed, and a fatigue testing machine is used to load the two loading frames (1), so as to test the tensile fatigue performance or the shear fatigue performance. A plurality of samples (5) can be mounted at the same time for testing the fatigue performance, and mutual influence is avoided, so that the test efficiency is effectively improved, the test cost is reduced, and the test cycle is shortened.

Description

Fatigue performance testing device and method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 13, 2023, with application number 202311327943.0 and invention name “A Fatigue Performance Testing Device and Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The invention belongs to the technical field of mechanical design, and relates to a fatigue performance testing device and method, which is suitable for measuring the tensile fatigue of superelastic rubber materials and the shear fatigue of the bonding between superelastic rubber materials and metals. Background Art

[0003] The fatigue properties of hyperelastic rubber materials were tested using a test method. The fatigue test method for vulcanized rubber under repeated tensile deformation is described in the standard GB / T1688-2008 / ISO6943:2007, "Rubber, vulcanized — Determination of tensile fatigue." The shear fatigue properties of rubber bonded between four parallel rigid plates were tested using the specimen configuration described in GB / T12830-2008 / ISO 1827:2007, "Rubber, vulcanized or thermoplastic — Determination of shear modulus and bond strength to rigid plates — Four-plate shear method." This fatigue test requires a specialized test setup to clamp and load the test specimens. Conventional test fixtures for tensile and shear fatigue testing of rubber materials clamp and load individual specimens. The corresponding test standards specify a specific number of specimens (≤ 5), requiring each specimen to be tested individually. The long fatigue test cycle significantly impacted the efficiency of the fatigue testing machine and increased testing costs.

[0004] Summary of the Invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology and propose a fatigue performance testing device and method, which can simultaneously install multiple specimens for fatigue performance testing without affecting each other, effectively improving the test efficiency, reducing the test cost, and shortening the test cycle.

[0006] The solution of the present invention is:

[0007] In a first aspect, the present invention provides a fatigue performance test device, which is used to test the tensile fatigue performance of rubber materials; it includes a loading frame, a pressing mechanism and a gasket;

[0008] The two loading frames are placed opposite to each other, one end of each loading frame is connected to the fatigue testing machine, and the other end is designed as multiple clamping interfaces. The clamping interfaces of the two loading frames correspond one to one, and each specimen is clamped between a corresponding set of clamping interfaces. Horizontal positioning bosses are designed on both sides of each clamping interface to limit the specimen; a gasket is installed between the specimen and the clamping interface; and a clamping mechanism is used to press the specimen onto the clamping interface.

[0009] Preferably, the pressing mechanism includes a pressing bolt and a pressing plate;

[0010] The pressure plate is installed in the clamping interface to compress the sample. Compressing holes are processed at the corresponding positions of the sample, gasket, pressure plate and clamping interface. The clamping bolts pass through the clamping holes in sequence to fix the sample on the clamping interface of the loading frame.

[0011] Preferably, the two opposite surfaces of the two loading frames are parallel and the sides are aligned.

[0012] Preferably, the transverse positioning boss is higher than the thickness of the gasket below the sample and lower than the sum of the thickness of the gasket below the sample and the compressed sample.

[0013] Preferably, the gasket material is a non-metallic material.

[0014] In a second aspect, the present invention provides a method for testing the tensile fatigue properties of a rubber material, comprising:

[0015] Fix the two loading frames on the positioning panel with positioning pins, with the two opposite faces of the two loading frames parallel and the sides aligned, and the clamping interfaces of the two loading frames corresponding to each other;

[0016] A thickness adjustment plate is placed between the two loading frames, and a gasket is placed on each clamping interface of the loading frame. The upper surfaces of the thickness adjustment plate and the gasket are flush, and the upper surfaces of the thickness adjustment plate and the gasket serve as the installation reference surface for the sample to be tested;

[0017] A sample to be tested is clamped between a set of clamping interfaces corresponding to two loading frames, and N sets of clamping interfaces are used to install N samples to be tested, wherein the samples to be tested are located on the installation reference surface;

[0018] Install a gasket between the upper surface of the sample to be tested and the clamping interface;

[0019] The sample to be tested is pressed onto the clamping interface by the pressing mechanism;

[0020] Remove the positioning panel, positioning pins and thickness adjustment plate;

[0021] Use a fatigue testing machine to load the two loading frames. The relative displacement of the two loading frames is the elongation and deformation of each specimen. Control the relative displacement of the two loading frames so that the elongation and deformation of the specimen are the preset index value. Record the number of loading times of the fatigue testing machine until the specimen is fatigue-damaged. Analyze whether the tensile fatigue performance of the specimen meets the requirements based on the number of loading times.

[0022] Preferably, transverse positioning bosses are designed on both sides of each clamping interface to limit the position of the sample.

[0023] Preferably, the transverse positioning boss is higher than the thickness of the gasket on the side close to the positioning panel, and lower than the sum of the thickness of the gasket and the compressed sample on the side close to the positioning panel.

[0024] In a third aspect, the present invention provides a fatigue performance test device, which is used to test the shear fatigue performance of rubber materials and includes two loading frames and a pressing mechanism;

[0025] The two loading frames are placed opposite to each other, one end of each loading frame is connected to the fatigue testing machine, and the other end is designed as multiple clamping interfaces. The clamping interfaces of the two loading frames correspond one to one, and each specimen is clamped between a corresponding set of clamping interfaces. Horizontal positioning bosses are designed on both sides of each clamping interface to limit the specimen; the clamping mechanism is used to press the specimen onto the clamping interface.

[0026] Preferably, the pressing mechanism includes a pressing bolt and a pressing plate;

[0027] The pressure plate is installed in the clamping interface to compress the sample. Compressing holes are processed at the corresponding positions of the sample, pressure plate and clamping interface. The clamping bolts pass through the clamping holes in sequence to fix the sample on the clamping interface of the loading frame.

[0028] Preferably, the two opposite surfaces of the two loading frames are parallel and the sides are aligned.

[0029] In a fourth aspect, the present invention provides a method for testing shear fatigue performance of a rubber material, comprising:

[0030] Fix the two loading frames on the positioning panel with positioning pins, with the two opposite faces of the two loading frames parallel and the sides aligned, and the clamping interfaces of the two loading frames corresponding to each other;

[0031] A sample to be tested is clamped between a set of clamping interfaces corresponding to two loading frames, and N sets of clamping interfaces are used to install N samples to be tested;

[0032] The sample is pressed onto the clamping interface by the pressing mechanism;

[0033] Remove the locating panel and locating pins;

[0034] Use a fatigue testing machine to load the two loading frames. The relative displacement of the two loading frames is the interlaminar shear displacement of each specimen. Control the relative displacement of the two loading frames so that the interlaminar shear displacement of the specimen is the preset index value. Record the number of loading times of the fatigue testing machine until the specimen is fatigue-damaged. Analyze whether the shear fatigue performance of the specimen meets the requirements based on the number of loading times.

[0035] The beneficial effects of the present invention compared with the prior art are:

[0036] (1) The present invention adopts a set of test equipment, and a single test can simultaneously perform fatigue tests on multiple specimens. During the test, the fatigue test results of each specimen are independent of each other and do not affect each other, which effectively improves the test efficiency, reduces the test cost, and shortens the test cycle.

[0037] (2) The present invention is applicable to the determination of the tensile fatigue properties of vulcanized rubber or thermoplastic rubber and the shear fatigue properties between vulcanized rubber or thermoplastic rubber and rigid plate layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of the tensile fatigue performance test state;

[0039] Figure 2 is a schematic diagram of the shear fatigue performance test state;

[0040] Figure 3 is a schematic diagram of the loading frame structure;

[0041] Figure 4 is a schematic diagram of the clamping of the tensile fatigue test specimen;

[0042] Figure 5 is a schematic diagram of the clamping of the shear fatigue test specimen;

[0043] FIG6 is a schematic diagram of the fixture for sample clamping without the adjustment plate installed;

[0044] Figure 7 is a schematic diagram of the fixture for installing the adjustment plate specimen clamp. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with the embodiments.

[0046] The present invention provides an efficient fatigue testing device that can simultaneously perform fatigue tests on multiple specimens, effectively improving test efficiency and shortening test cycles. The device can be used to test the tensile fatigue properties of vulcanized or thermoplastic rubber, and the shear fatigue properties between vulcanized or thermoplastic rubber and a rigid plate, by simply adding or removing spacers.

[0047] As shown in Figure 1, the present invention presents a highly efficient test apparatus for tensile fatigue properties of rubber materials, comprising a loading frame 1, a clamping mechanism, and a gasket 3. Specimens 5 serve as the test subjects. Each specimen 5 is secured at both ends by a clamping mechanism, and multiple specimens 5 share a single loading frame 1 at one end. Figure 3 shows a schematic diagram of the loading frame structure.

[0048] The two opposite faces of the two loading frames are parallel and the sides are aligned. One end of the loading frame 1 is connected to the fatigue testing machine, and the other end is designed as a plurality of clamping interfaces. The clamping interfaces of the two loading frames correspond one to one, and each specimen 5 is clamped between a corresponding set of clamping interfaces, ensuring that the neutral surfaces of each specimen 5 are parallel to each other. The gasket 3 is installed on the upper and lower surfaces of the specimen 5 to protect the specimen 5 from being crushed; the clamping mechanism is used to press the specimen 5 on the clamping interface; the transverse positioning boss of the specimen 5 is designed on both sides of each clamping interface, and the height of the boss should be higher than the thickness of the gasket 3 under the specimen, and lower than the sum of the thickness of the gasket 3 and the specimen 5 under the specimen after compression.

[0049] The clamping mechanism includes a clamping bolt 2 and a pressure plate 4. Multiple sets of specimen clamping holes are designed on the loading frame 1 according to test requirements. The pressure plate 4 is installed in the clamping interface to compress the specimen. Compressing holes are machined in corresponding positions on the specimen 5, gasket 3, and pressure plate 4. Compression bolts 2 pass through these holes in sequence to secure the specimen to the loading frame's clamping interface. Therefore, each specimen 5 is secured at both ends by a loading frame 1, two gaskets 3, a pressure plate 4, and a clamping bolt 2. Each set of loading frames 1 can simultaneously accommodate multiple sets of specimens 5.

[0050] In addition, to assemble the test device, an assembly tool for the test device is required, namely the positioning panel 6, positioning pins 8, and thickness adjustment plate 7. The positioning panel 6, thickness adjustment plate 7, and positioning pins 8 ensure that the free length of multiple specimens 5 between the two loading frames 1 remains consistent after assembly.

[0051] In the tensile fatigue performance test device, the material of the sample 5 is rubber material, which has poor rigidity. When fixing, the positioning panel 6 and the two loading frames 1 need to be fixed by the positioning pins 8 to ensure that the two opposite surfaces of the two loading frames 1 are parallel and the sides are aligned. The thickness adjustment plate 7 is used to adjust so that the sample 5 always maintains a natural state during the installation process and does not deform.

[0052] Using the above-mentioned rubber material tensile fatigue performance test device, the present invention provides a rubber material tensile fatigue performance test method, which is as follows:

[0053] Place the positioning panel 6 on the operating table and position the two loading frames 1 on the positioning panel 6 using the positioning pins 8, ensuring that their corresponding surfaces are parallel. Place a thickness adjustment plate 7 between the two loading frames 1, and place a gasket 3 on each clamping interface of the loading frame 1. The upper surfaces of the thickness adjustment plate 7 and the gasket 3 are flush. This plane serves as the installation reference surface for the specimen 5, ensuring that the specimen 5 made of softer rubber material is in a free and flat state during installation. Then, place the specimen 5 at the clamping interface position on the plane where the upper surfaces of the thickness adjustment plate 7 and the gasket 3 are located. Use the lateral positioning steps on both sides of the corresponding clamping interface on the loading frame 1 to limit the position, then place the gasket 3 on the other side of the specimen 5, and finally secure it with the tightening bolts 2 and the pressure plate 4. When conducting the test, remove the thickness adjustment plate, positioning pins 8, and positioning panel. The fatigue testing machine is fixed to the upper and lower loading frames 1 respectively, and fatigue performance tests are performed on multiple groups of specimens 7 installed on the loading frame 1 at the same time. That is, the two loading frames are loaded using the loading fixture of the fatigue testing machine. The relative displacement of the two loading frames is the elongation deformation of each specimen. The relative displacement of the two loading frames is controlled so that the elongation deformation of the specimen is the preset index value. The number of loading times of the fatigue testing machine is recorded until the specimen is fatigue-damaged. The tensile fatigue performance of the specimen is analyzed based on the number of loading times to see whether it meets the requirements. Fatigue damage of any group of specimens 5 has no effect on other specimens. Figure 4 is a schematic diagram of the clamping of tensile fatigue test specimens. Figure 6 is a schematic diagram of the fixture for clamping specimens without the adjustment plate installed, and Figure 7 is a schematic diagram of the fixture for clamping specimens with the adjustment plate installed. The upper right end of Figure 7 shows the lateral positioning boss, and the lower end shows the specimen installation reference surface.

[0054] In order to prevent the gasket 3 from causing compression damage to the sample 5, the gasket 3 is designed to be a non-metallic material with a low elastic modulus (1-10 GPa), and the tightening torque of the fixed clamping bolt 2 is used to ensure the compression consistency of the sample 5.

[0055] As shown in Figure 2, a high-efficiency rubber material shear fatigue performance test device includes two loading frames 1 and a clamping mechanism. The two opposite surfaces of the two loading frames are parallel and aligned laterally. One end of the loading frame is connected to the fatigue testing machine, and the other end is designed as a plurality of clamping interfaces. The clamping interfaces of the two loading frames correspond one to one, and each specimen 5 is clamped between a corresponding set of clamping interfaces; lateral positioning bosses of the specimen 5 are designed on both sides of each clamping interface, and the clamping mechanism is used to clamp the specimen 5 on the clamping interface. The clamping mechanism includes a clamping bolt 2 and a pressure plate 4. The pressure plate 4 is installed in the clamping interface to press the specimen. The corresponding positions of the specimen 5, the pressure plate 4, and the clamping interface are machined with clamping holes. The clamping bolt 2 passes through the clamping holes in sequence to fix the specimen on the clamping interface of the loading frame. In the shear fatigue performance test, the specimen 5 is a composite structure of rubber bonded between four parallel rigid plates.

[0056] When conducting a shear fatigue test, multiple specimens 5 are directly mounted on two loading frames 1 and fixed by tightening bolts 2 and pressure plates 4. The two loading frames are loaded using a fatigue testing machine loading fixture. The relative displacement of the two loading frames is the interlayer shear displacement of each specimen. The relative displacement of the two loading frames is controlled so that the interlayer shear displacement of the specimen is a preset index value. The number of loading times of the fatigue testing machine is recorded until the specimen is fatigue-damaged. Based on the number of loading times, it is analyzed whether the shear fatigue performance of the specimen meets the requirements. Fatigue failure of any group of specimens 5 has no effect on other specimens. Figure 5 is a schematic diagram of the clamping of shear fatigue test specimens.

[0057] Example:

[0058] The device of the present invention was used to carry out tensile fatigue performance tests and shear fatigue performance tests on dumbbell specimens. The two tests shared the same set of loading frames, but according to the specific conditions of the specimens, two clamping holes were opened on the loading frame corresponding to each clamping interface, one for the tensile fatigue performance test and the other for the shear fatigue performance test.

[0059] The examples show that the present invention can simultaneously install multiple specimens for fatigue performance testing without affecting each other, thereby effectively improving the test efficiency and shortening the test cycle.

[0060] The technologies not disclosed in the present invention are common knowledge to those skilled in the art.

Claims

1. A fatigue performance test device, characterized in that: The test device is used to test the tensile fatigue performance of rubber materials; it comprises a loading frame (1), a clamping mechanism and a gasket (3); Two loading frames (1) are placed opposite to each other, one end of each loading frame is connected to a fatigue testing machine, and the other end is designed as a plurality of clamping interfaces, the clamping interfaces of the two loading frames correspond to each other, each specimen (5) is clamped between a corresponding set of clamping interfaces, and both sides of each clamping interface are designed with lateral positioning bosses for limiting the position of the specimen (5); a gasket (3) is installed between the specimen (5) and the clamping interface; and a clamping mechanism is used to clamp the specimen (5) onto the clamping interface.

2. A fatigue performance test device according to claim 1, characterized in that: The clamping mechanism comprises a clamping bolt (2) and a clamping plate (4); The pressure plate (4) is installed in the clamping interface to clamp the sample. Compressing holes are processed at corresponding positions of the sample (5), the gasket (3), the pressure plate (4) and the clamping interface. The clamping bolts (2) pass through the clamping holes in sequence to fix the sample on the clamping interface of the loading frame.

3. A fatigue performance test device according to claim 1, characterized in that: The two opposite faces of the two loading frames are parallel and the sides are aligned.

4. A fatigue performance test device according to claim 1, characterized in that: The lateral positioning boss is higher than the thickness of the gasket under the specimen, and lower than the sum of the thickness of the gasket under the specimen and the compressed specimen.

5. A fatigue performance test device according to claim 1, characterized in that: The gasket material is non-metallic material.

6. A method for testing the tensile fatigue performance of a rubber material, characterized in that: include: Fix the two loading frames on the positioning panel through positioning pins, the two opposite faces of the two loading frames are parallel and the sides are aligned, and the clamping interfaces of the two loading frames correspond one to one; A thickness adjustment plate is placed between the two loading frames, and a gasket is placed on each clamping interface of the loading frame. The upper surfaces of the thickness adjustment plate and the gasket are flush, and the upper surfaces of the thickness adjustment plate and the gasket serve as the installation reference surfaces of the sample to be tested; A sample to be tested is clamped between a set of clamping interfaces corresponding to two loading frames. Installing N samples to be tested, wherein the samples to be tested are located on the installation reference surface; Install a gasket between the upper surface of the sample to be tested and the clamping interface; The sample to be tested is pressed onto the clamping interface by means of a pressing mechanism; Remove the positioning panel, positioning pins and thickness adjustment plate; Use a fatigue testing machine to load the two loading frames. The relative displacement of the two loading frames is the elongation and deformation of each specimen. The relative displacement of the two loading frames is controlled so that the elongation and deformation of the specimen is the preset index value. The number of loading times of the fatigue testing machine is recorded until the specimen is fatigue-damaged. According to the number of loading times, it is analyzed whether the tensile fatigue performance of the specimen meets the requirements.

7. A method for testing the tensile fatigue properties of a rubber material according to claim 6, characterized in that: Transverse positioning bosses are designed on both sides of each clamping interface to limit the position of the specimen.

8. A method for testing the tensile fatigue properties of a rubber material according to claim 7, characterized in that: The transverse positioning boss is higher than the thickness of the gasket on the side close to the positioning panel, and lower than the sum of the thickness of the gasket and the specimen after compression on the side close to the positioning panel.

9. A fatigue performance test device, characterized in that: The test device is used to test the shear fatigue performance of rubber materials, and includes two loading frames and a clamping mechanism; Two loading frames (1) are placed opposite to each other, one end of each loading frame is connected to the fatigue testing machine, and the other end is designed as a plurality of clamping interfaces, the clamping interfaces of the two loading frames correspond to each other, each specimen (5) is clamped between a corresponding set of clamping interfaces, and both sides of each clamping interface are designed with lateral positioning bosses for limiting the position of the specimen (5); the clamping mechanism is used to clamp the specimen (5) onto the clamping interface.

10. A fatigue performance test device according to claim 9, characterized in that: The clamping mechanism comprises a clamping bolt (2) and a clamping plate (4); The pressure plate (4) is installed in the clamping interface to clamp the sample. Compressing holes are processed at corresponding positions of the sample (5), the pressure plate (4) and the clamping interface. The clamping bolts (2) pass through the clamping holes in sequence to fix the sample on the clamping interface of the loading frame.

11. A fatigue performance test device according to claim 9, characterized in that: The two opposite faces of the two loading frames are parallel and the sides are aligned.

12. A method for testing shear fatigue performance of rubber materials, characterized in that: include: Fix the two loading frames on the positioning panel through positioning pins, the two opposite faces of the two loading frames are parallel and the sides are aligned, and the clamping interfaces of the two loading frames correspond one to one; A sample to be tested is clamped between a set of clamping interfaces corresponding to two loading frames, and N sets of clamping interfaces are used to install N samples to be tested; The sample is pressed onto the clamping interface by means of a pressing mechanism; Remove the locating panel and locating pins; The fatigue testing machine is used to load the two loading frames. The relative displacement of the two loading frames is the interlaminar shear displacement of each specimen. The relative displacement of the two loading frames is controlled so that the interlaminar shear displacement of the specimen is the preset index value. The number of loading times of the fatigue testing machine is recorded until the specimen is fatigue-damaged. The shear fatigue performance of the specimen is analyzed based on the number of loading times to see whether it meets the requirements.

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