A new multifunctional anchoring device for pull-off tests

Abstract

The present application relates to a kind of new multifunctional anchoring device for pull test, the device includes two identical clamps, respectively, upper clamping part and lower clamping part are arranged vertically, each of the described clamp includes end plate connected to apply pressure and support plate to clamp one end of test piece, the end plate and support plate are connected by screw rod, load transfer block is arranged on the screw rod to transfer force, square hole is respectively opened on the support plate to pass through load transfer block, the press is used to apply pressure to upper end plate and lower end plate, the upper clamping part, lower clamping part, press and load transfer block cooperate to realize the tension test and pressure test to test piece.Compared with prior art, the present application has the advantages of simple structure, easy assembly and disassembly and improving the accuracy of measurement data.

Description

Technical Field

[0001] This invention relates to the field of materials mechanics research, and in particular to a novel multifunctional anchoring device for tensile and compressive testing. Background Technology

[0002] Currently, tensile and compressive strength tests are important parameters for assessing the performance of stone. Tensile testing is a fundamental experimental method for testing the tensile strength and deformation capacity of various metallic and non-metallic materials. The American Society for Testing and Materials (ASMT) stipulates that the bonding adhesive between the loading platform and the specimen surface may not be suitable for high-strength stone due to performance limitations; the adhesive may have already failed before the specimen is stretched. In tensile tests of other materials, there are two methods for clamping the specimen: one is through the self-locking force of the clamping blocks, generating clamping force and frictional resistance between the clamping blocks and the specimen. This is mainly achieved by the frictional force generated between the toothed marks on the clamping block surface and the specimen, causing the wedge-shaped clamp to engage in the tensile direction, thereby further increasing the compressive force and frictional resistance of the wedge-shaped clamping block on the specimen's clamping end; the other method is to shape the specimen end to fit the clamp to fix it, typically using a dumbbell-shaped clamp. This clamping method requires high-precision manufacturing technology for the clamps, and manufacturing matching clamps for specimens with the same shape but different dimensions is costly. Summary of the Invention

[0003] The purpose of this invention is to overcome the defects of the prior art and provide a new type of multifunctional anchoring device for tensile and compressive testing.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A novel multifunctional anchoring device for tensile and compressive testing includes two identical clamps: an upper clamping component and a lower clamping component arranged perpendicularly to each other. Each clamp includes an end plate and a support plate. The end plate is connected to a press, and the end plate and the support plate are connected by a screw. A load transfer block is provided on the screw. Square holes for the load transfer blocks to pass through are respectively opened on the support plate. The press applies pressure to the end plate. The upper clamping component, the lower clamping component, the press, and the load transfer block cooperate with each other to perform tensile and compressive tests on the specimen.

[0006] The upper clamping component includes an upper end plate connected to the press and an upper support plate for clamping one end of the specimen, and the lower clamping component includes a lower end plate connected to the press and a lower support plate for clamping the other end of the specimen.

[0007] The screw includes an upper screw and a lower screw. The upper end plate and the upper support plate are connected by the upper screw, and the lower end plate and the lower support plate are connected by the lower screw.

[0008] The upper support plate and the lower support plate have the same structure, both consisting of two clamping plates arranged vertically. Each clamping plate includes a clamping part with a semi-circular section cut out on one side, a support part connected to the upper side of one end of the clamping part, and a support part connected to the lower side of the other end of the clamping part. The two clamping plates are arranged opposite each other and clamped together so that the clamping parts of the two clamping plates form a groove that fits with the specimen. The groove is used to clamp one end of the specimen.

[0009] Square holes are respectively opened on the two support parts of the upper and lower support plates.

[0010] The upper end plate and the lower end plate have the same structure. The upper end plate has a screw hole at the position corresponding to the square hole of the upper support plate for the upper screw to pass through.

[0011] The upper end plate and the lower end plate are provided with grooves in the middle to achieve the positioning of different press loading heads.

[0012] One end of the upper screw is threaded and passes through the threaded hole of the upper end plate. The other end of the upper screw is provided with a load transfer block and passes through the square hole of the upper bearing plate. One end of the lower screw is threaded and passes through the threaded hole of the lower end plate. The other end of the lower screw is provided with a load transfer block and passes through the square hole of the lower bearing plate.

[0013] The specimens include dumbbell-shaped specimens, dog bone-shaped specimens, and plate-shaped specimens.

[0014] The working principle of this device is as follows:

[0015] During the tensile test, the upper end plate is fixed to the upper end of the upper screw by the upper nut, and the other end of the upper screw is connected to the upper bearing plate. The upper bearing plate bears the load of the press through the load transfer block and fixes the lower end of the specimen. The lower bearing plate fixes the upper end of the specimen. The direction of the load transfer block on the lower screw is adjusted so that the lower bearing plate is located on the upper side of the load transfer block. The lower end plate is fixed to the lower end of the lower screw by the lower nut. The upper end plate and the lower end plate bear the load of the loader respectively, and the specimen is stretched at both ends.

[0016] During the compression test, the upper end plate is fixed to the upper end of the upper screw by the upper nut, and the upper bearing plate fixes the lower end of the specimen. The load transfer block on the upper screw is reversed so that it passes through the upper bearing plate, and the upper end plate directly acts on the top surface of the specimen. The lower end plate is fixed to the lower end of the lower screw by the lower nut and contacts the bottom surface of the specimen. The load transfer block on the lower screw is reversed so that it passes through the lower bearing plate, and the lower bearing plate is not subjected to force. The upper end plate and the lower end plate respectively bear the load of the loader, compressing both ends of the specimen.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. This invention uses a multi-functional tension and compression clamp to ensure that the contact surface of the material and the contact surface of the clamp are fully fitted, resulting in uniform force transmission. The combination of the two support plates also makes installation more convenient. This invention is not only simple in structure and easy to assemble and disassemble, but also solves the problem of difficulty in clamping brittle materials.

[0019] 2. This invention reduces material eccentricity during testing by fixing the support plate, thus preventing the stone from twisting and bending, which could affect the accuracy of the measured data and improve the accuracy of the test.

[0020] 3. When conducting tensile and compressive tests, this invention only requires changing the direction of the load transfer block to change the test, eliminating the need for new fixtures. This not only reduces the cost of manufacturing fixtures but also makes the operation convenient.

[0021] 4. The test specimens used in this invention can be adjusted in terms of material, shape, and size, making it widely applicable. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention under tensile testing.

[0023] Figure 2 This is a schematic diagram of the structure of the present invention under pressure testing.

[0024] Figure 3 This is a three-dimensional schematic diagram of the clamp of the present invention.

[0025] Figure 4 This is a top view of the end plate of the present invention.

[0026] Figure 5 This is a front view of the end plate of the present invention.

[0027] Figure 6 This is a top view of the nut of the present invention.

[0028] Figure 7 This is a front view of the screw and load transfer block of the present invention.

[0029] Figure 8 This is a top view of the bearing plate of the present invention.

[0030] Figure 9 This is a front view of the bearing plate of the present invention.

[0031] Figure 10 The stress-strain curves corresponding to the tensile test in an embodiment of the present invention are shown.

[0032] Figure 11The stress-strain curves corresponding to the pressure test in an embodiment of the present invention are shown.

[0033] Reference numerals: 1. Upper screw, 2. Upper nut, 3. Upper end plate, 4. Lower screw, 5. Lower bearing plate, 6. Load transfer block, 7. Specimen, 8. Upper bearing plate, 9. Lower nut, 10. Lower end plate. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0035] like Figures 1-2 As shown, where, Figure 1 This describes the setup for the tensile test. Figure 2 For the pressure test setup, the upper end plate 3 of the upper clamping component is connected to the press and the upper screw 1. The upper support plate 8 clamps one end of the specimen 7 in the groove of the upper support plate 8. The upper end plate 3 is connected to the upper support plate 8 through the upper screw 1, and the upper end plate 3 is fastened to the upper screw 1 through the upper nut 2. Then, the loader is used to apply pressure directly to the upper end plate 3. The lower end plate 10 of the lower clamping component is connected to the press and the lower screw 4. The lower support plate 5 clamps the other end of the specimen 7 in the groove of the lower support plate 5. The lower end plate 10 is connected to the lower support plate 5 through the lower screw 4, and the lower end plate 10 is fastened to the lower screw 4 through the lower nut 9. Then, the load of the loader is applied directly to the lower end plate 10.

[0036] like Figure 3 As shown, the upper clamping component includes an upper end plate 3, an upper support plate 8, an upper screw 1, a load transfer block 6, and an upper nut 2. The lower clamping component includes a lower end plate 10, a lower support plate 5, a lower screw 4, a load transfer block 6, and a lower nut 9. The upper end plate 3, lower end plate 10, upper support plate 8, lower support plate 5, load transfer block 6, upper screw 1, lower screw 4, upper nut 2, and lower nut 9 are all made of 316 stainless steel.

[0037] The upper end plate 3 and the lower end plate 10 are connected to the press and are used to bear the load of the press loading head. The upper end plate 3 and the lower end plate 10 are respectively provided with screw holes at both ends. The diameter of the screw holes is 27mm, and the middle is provided with a groove that matches the press loading head.

[0038] The upper support plate 8 and the lower support plate 5 are used to fix the end of the specimen 7. The upper support plate 8 and the lower support plate 5 are both composed of two clamping plates arranged one above the other. Each clamping plate includes a clamping part with a semi-circle cut out on one side, a support part connected to the upper side of one end of the clamping part, and a support part connected to the lower side of the other end of the clamping part. The two clamping plates are arranged opposite to each other to form a groove for fitting with the specimen 7. The groove is used to clamp one end of the specimen 7. The groove fits with the specimen 7 to ensure uniform force. The specimen 7 includes dumbbell-shaped specimens, dog bone-shaped specimens, and plate-shaped specimens.

[0039] The upper support plate 8 and the upper end plate 3 are connected by the upper screw 1, and the lower support plate 5 and the lower end plate 10 are connected by the lower screw 4.

[0040] The two ends of the upper screw 1 are assembled with the square holes of the upper bearing plate 8 through the screw holes on the upper end plate 3, and the two ends of the lower screw 4 are assembled with the square holes of the lower bearing plate 5 through the screw holes on the lower end plate 10. The load transfer block 6 is set on the upper screw 1 and the lower screw 4 to transfer the force to the specimen 7.

[0041] The upper nut 2 is used to connect the upper screw 1 and the upper end plate 3, and the lower nut 9 is used to connect the lower screw 4 and the lower end plate 10.

[0042] like Figures 4-5 As shown, the upper end plate 3 and the lower end plate 10 are respectively provided with grooves in the center. The position of the press is positioned by the grooves in the center to ensure that no eccentricity will occur under the action of vertical force during the test.

[0043] like Figure 6 As shown, the upper nut 2 fixes the upper screw 1 to the upper end plate 3, and the lower nut 9 fixes the lower screw 4 to the lower end plate 10.

[0044] like Figure 7 As shown, the lower screw 4 and the load transfer block 6 are used to connect the lower end plate 10 and the lower bearing plate 5 and transfer the load. The lower screw 4 has a diameter of 25mm, a total length of 280mm, and a thread length of 100mm. The load transfer block 6 is 60mm away from the end of the upper screw 1 or the lower screw 4. The load transfer block 6 has a length of 50mm, a width of 25mm, and a height of 27mm.

[0045] like Figures 8-9 As shown, the upper support plate 8 and the lower support plate 5 are used to fix the position of the specimen 7. The specimen 7 includes dumbbell-shaped specimens, plate-shaped specimens, cylindrical specimens and dog bone-shaped specimens. The size of the specimens can be adjusted by themselves. The material properties of the specimens include brittle materials such as concrete and stone.

[0046] This invention is extremely convenient to operate when testing the tensile and compressive strength of stone, and the test values ​​are highly accurate. The clamping device is also easy to install and disassemble. Moreover, since the clamp itself fits the specimen well, it can reduce the phenomenon of local stress concentration in the stone during the tensile process. In addition, this device is easy to install. By applying pressure to the end plate and adjusting the direction of the load transfer block 6, the same specimen can be tested for tensile and compressive forces during the test.

[0047] For example, in tensile tests on granite and ceramic materials, this invention connects the upper end plate 3 and the upper support plate 8 via an upper screw 1. The upper support plate 8 clamps one end of the granite and ceramic specimens at a slot. Then, a loader applies a load directly to the upper end plate 3, while the other end of the granite and ceramic specimens is clamped at a slot in the lower support plate 5 in the same manner. The test data is output through a press, and the corresponding stress-strain curves are shown below. Figure 10 and Figure 11 As shown in Tables 1 and 2, the peak tensile strength and elastic modulus of the granite and ceramic specimens are respectively:

[0048] Table 1 Peak Tensile Strength and Elastic Modulus of Granite Specimens

[0049]

[0050]

[0051] Table 2 Peak Tensile Strength and Elastic Modulus of Ceramic Specimens

[0052]

[0053] From Table 1, Table 2, Figure 10 and Figure 11 The test results show that the present invention can obtain the stress-strain curve of the material. The percentages of the ratio of the standard deviation of tensile strength and the strength of the two sets are 6.0% and 3.3%, respectively, indicating that the test results measured by this device have a small degree of dispersion and high accuracy.

[0054] This invention avoids the uneven stress distribution that often occurs in tensile tests. During the tensile process, the contact surface between the clamp and the specimen is uniformly stressed, preventing localized stress concentrations that could lead to localized premature failure of the stone. Furthermore, the rotating load transfer block during unloading allows for the conversion between tensile and compressive tests. Compared to other devices, this invention is simpler and more convenient to install, requiring no hydraulic system for fixation. Only a pressure device is needed to perform tensile and compressive tests on brittle materials. By adjusting the direction of the load transfer block, the parameters of the same specimen under tensile and compressive loads can be compared during the test.

[0055] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A new multi-functional anchoring device for pull-off test, characterized in that, The device comprises two structural identical clamps, which are upper clamping part and lower clamping part arranged vertically, each of the clamps comprises an end plate and a bearing plate, the end plate is connected with a press, the end plate and the bearing plate are connected through a screw rod, the screw rod is provided with a load transfer block (6), the bearing plate is provided with a square hole for passing through the load transfer block (6), the press is used to apply pressure to the end plate, the upper clamping part, the lower clamping part, the press and the load transfer block (6) cooperate with each other to realize the tension test and the compression test on the test piece (7); The upper clamping part comprises an upper end plate (3) connected with the press and an upper bearing plate (8) for clamping one end of the test piece (7), and the lower clamping part comprises a lower end plate (10) connected with the press and a lower bearing plate (5) for clamping the other end of the test piece (7); The screw rod comprises an upper screw rod (1) and a lower screw rod (4), the upper end plate (3) and the upper bearing plate (8) are connected through the upper screw rod (1), and the lower end plate (10) and the lower bearing plate (5) are connected through the lower screw rod (4); The upper bearing plate (8) and the lower bearing plate (5) are the same in structure and are composed of two upper and lower clamping plates, each of the clamping plates comprises a clamping part with a semicircle on one side, a supporting part connected with the upper side of one end of the clamping part and a supporting part connected with the lower side of the other end of the clamping part, the two clamping plates are arranged oppositely and clamped to each other, so that the clamping parts of the two clamping plates form a slot for fitting the test piece (7), and the slot is used to clamp one end of the test piece (7); Square holes are formed in the two supporting parts of the upper bearing plate (8) and the lower bearing plate (5); The upper end plate (3) and the lower end plate (10) are the same in structure, the upper end plate (3) is provided with a screw hole corresponding to the square hole of the upper bearing plate (8); One end of the upper screw rod (1) is provided with a thread and passes through the screw hole of the upper end plate (3), the other end of the upper screw rod (1) is provided with a load transfer block (6) and passes through the square hole of the upper bearing plate (8), one end of the lower screw rod (4) is provided with a thread and passes through the screw hole of the lower end plate (10), and the other end of the lower screw rod (4) is provided with a load transfer block (6) and passes through the square hole of the lower bearing plate (5); The upper end plate (3) and the lower end plate (10) are provided with grooves in the middle for positioning different press loading heads.

2. A new multi-functional anchorage device for pull testing as claimed in claim 1, wherein, The test piece (7) comprises a dumbbell-shaped test piece, a dog bone-shaped test piece and a plate-shaped test piece.

3. The new multifunctional anchoring device for pull-off test according to any one of claims 1-2, characterized in that, The working principle of the device is as follows: When the tensile test is carried out, the upper end plate (3) is fixed on the upper end of the upper screw rod (1) through the upper nut (2), the other end of the upper screw rod (1) is connected with the upper bearing plate (8), the upper bearing plate (8) bears the load of the press machine through the load transfer block (6) and fixes the lower end of the test piece (7), the lower bearing plate (5) fixes the upper end of the test piece (7), the direction of the load transfer block (6) on the lower screw rod (4) is adjusted so that the lower bearing plate (5) is located on the upper side of the load transfer block (6), the lower end plate (10) is fixed on the lower end of the lower screw rod (4) through the lower nut (9), the upper end plate (3) and the lower end plate (10) bear the load of the loading machine respectively, and the two ends of the test piece (7) are stretched; When the compression test is carried out, the upper end plate (3) is fixed on the upper end of the upper screw rod (1) through the upper nut (2), the lower end of the test piece (7) is fixed on the upper bearing plate (8), the load transfer block (6) on the upper screw rod (1) is converted in direction so as to pass through the upper bearing plate (8), the upper end plate directly acts on the top surface of the test piece (7), the lower end plate (10) is fixed on the lower end of the lower screw rod (4) through the lower nut (9) and is in contact with the bottom surface of the test piece (7), the load transfer block (6) on the lower screw rod (4) is converted in direction so as to pass through the lower bearing plate (5), the lower bearing plate (5) is not stressed, the upper end plate (3) and the lower end plate (10) bear the load of the loading machine respectively, and the two ends of the test piece (7) are compressed.

Images