A ring groove rivet mechanical property experiment table and an experiment method thereof

Abstract

The application discloses a ring groove rivet mechanical property experiment table and an experiment method thereof, and is used for experimentally detecting the clamping force and the pull-off force of the ring groove rivet. The experiment table is composed of the following components arranged on a platform, a long screw rod, a support, two groups of hydraulic oil cylinders, a pull-off push plate, two sets of pull-off toolings, two sets of clamping toolings, two sets of axial force sensors and a dovetail groove connecting tooling. The experiment table is composed of the long screw rod, an experiment tooling, a tooling gap, an experiment tooling and a sleeve ring. The minimum connection thickness requirement of the ring groove rivet clamping force experiment is greatly reduced, the requirement that the connection thickness of the ring groove rivet connecting pair should not be less than two times the nominal diameter according to the national standard is met, and the clamping force and the pull-off force experiments of the ring groove rivet connecting pair are carried out. The experiment table is of a detachable structure, the replacement of the easily damaged and consumed components is convenient, the dovetail groove connecting tooling and the riveting support plate can be replaced, the size change of the ring groove rivet is adapted, the mechanical property experiment requirements of the M6-M64 full series of ring groove rivets are met.

Description

Technical Field

[0001] This invention relates to the field of experimental testing equipment design and application technology, and specifically to the design and application of an experimental testing device for the clamping force and pull-out force of a ring groove rivet connection pair. Background Technology

[0002] As a type of fastener that will never loosen after installation, the ring groove rivet connection pair is based on the principle of metal plastic deformation. Because the metal undergoes permanent plastic deformation after installation, the deformed metal of the collar is squeezed into the independent ring groove of the rivet, so disassembly is extremely simple.

[0003] When conducting batch tests on the mechanical and physical properties of grooved rivet connections, such as clamping force and pull-out force, it is necessary to disassemble the grooved rivets, collars, axial force sensors, and testing fixtures using a large tensile testing machine. This process is labor-intensive, inefficient, and carries the risk of injury to personnel from falling heavy objects during transport. Conventional tests on grooved rivet connections for clamping force and pull-out force require a hydraulic pump station, a specialized rivet gun, an axial force sensor, a large tensile testing machine, and multiple sets of testing fixtures. The process involves moving the testing equipment back and forth, making the procedures cumbersome and resulting in high labor intensity and low efficiency for personnel. GB / T 36993-2018, "Technical Conditions for Groove Rivet Connections," stipulates that the clamping thickness for the clamping force test of groove rivet connections should not be less than twice its nominal diameter. This means that all groove rivet connections with a connection thickness of not less than twice the nominal diameter must undergo a clamping force test. However, in reality, the thickness of large-range axial force sensors is relatively large, generally falling slightly below or exceeding twice the nominal diameter of the groove rivet. This results in some groove rivet connections with a smaller connection thickness being unable to undergo a clamping force test and thus failing to meet the national standard requirements. Summary of the Invention

[0004] This invention discloses a mechanical performance testing platform for grooved rivets and its experimental method. The purpose of this invention is to provide a testing device for the mechanical and physical properties of grooved rivet connections, such as clamping force and pull-out force. The testing platform of this invention can complete the mechanical and physical property tests of clamping force and pull-out force in one go using a single grooved rivet connection.

[0005] This invention is achieved through the following technical solution:

[0006] A mechanical property testing platform for grooved rivets is used to test the clamping force and pull-out force of grooved rivets; characterized in that it consists of the following components set on a platform;

[0007] A long screw, with a T-shaped connector at one end and external threads on the shaft;

[0008] A support includes: a planar fixed support plate with a central opening for a long screw to pass through freely; two sets of L-shaped support legs arranged in parallel, with the L-shaped feet supporting and fixing the plate surface during testing; and a planar riveting support plate with a central opening for a ring groove rivet to pass through freely, with its two ends supporting and fixing the other ends of the two support legs respectively during testing.

[0009] Two sets of hydraulic cylinders are fixed parallel to each other on the platform surface, and their rear ends are supported and connected to the other side of the fixed bracket plate.

[0010] A pull-out push plate, which is a planar structure, allows for separable contact between the two ends of the planar pull-out push plate and the pistons of two sets of hydraulic cylinders during testing.

[0011] Both sets of pull-out fixtures are flat pads with a central hole for the long screw to pass through freely; both sets of clamping fixtures are flat pads with a central hole for the long screw to pass through freely.

[0012] Two sets of axial force sensors; one axial force sensor is mounted on the long screw for pull-out force detection, and is installed between two sets of pull-out fixtures. The outer end of the pull-out fixture is fixed by a positioning nut, and the inner end of the pull-out fixture is in contact with the pull-out push plate; the second axial force sensor is mounted on the long screw for clamping force detection, and is installed between two sets of clamping fixtures. The outer end of the clamping fixture is fixed by a positioning nut, and the inner end of the clamping fixture is in contact with the fixed bracket plate of the bracket.

[0013] A dovetail groove connecting fixture has a T-shaped dovetail groove with an embedded structure that can be detachably connected to a long screw T-shaped connector. A through hole is provided at the center of the bottom of the dovetail groove for the insertion and fixing of a ring groove rivet for inspection.

[0014] Furthermore, the planar pads constituting the two sets of pull-out fixtures and the two sets of clamping fixtures of the present invention are square or circular planes, the side length or diameter of which is larger than the diameter of the axial force sensor, so that the two planes of the axial force sensor are fully covered.

[0015] Furthermore, the hydraulic cylinder and riveting tool described in this invention are both fixed to the platform by arc-shaped pads, and the central axis of the riveting tool and the hydraulic cylinder is parallel to the central axis of the rivet.

[0016] Furthermore, the two sets of hydraulic cylinders described in this invention are respectively fixed by two positioning bases fixed to the platform. The front ends of the two positioning bases are the positioning positions of the fixed support plate and are combined with the limiting position of the fixed support plate.

[0017] Furthermore, the distance between the fixed bracket plate and the dovetail groove connecting fixture of the present invention is greater than the exposed length of the annular groove rivet.

[0018] This invention also discloses a method for testing the mechanical properties of ring groove rivets using the aforementioned ring groove rivet mechanical property testing bench, comprising the following steps:

[0019] Step 1: Pass the test piece ring groove rivet through the center hole of the dovetail groove connecting tool;

[0020] Step 2: Fit the dovetail groove connecting fixture with the test piece ring groove rivet into the long screw T-shaped connector, and then insert the other end of the long screw into the fixed bracket plate;

[0021] Step 3: Insert the tail of the ring groove rivet into the riveting bracket plate and the collar in sequence; place the L-shaped support leg parallel between the fixed bracket plate and the riveting bracket plate; adjust the position of the collar and ensure the gap between the dovetail groove connecting tool and the riveting bracket plate so that the dovetail groove connecting tool and the riveting bracket plate form a non-contact structure.

[0022] Step 4: Install clamping fixture 2, axial force sensor 2, and clamping fixture 1 sequentially onto the threaded end of the long screw. Screw in a positioning nut. Adjust the position of the positioning nut to form a clamping force test connection body with clamping fixture 1, axial force sensor 2, clamping fixture 2, fixed bracket plate, dovetail groove connecting fixture, riveting bracket plate, and test annular groove rivet.

[0023] Step 5: Connect the riveting tool with the ring groove rivet collar to prepare for extrusion riveting. Start the riveting tool to complete the installation of the ring groove rivet. Record the data after the axial force sensor II stabilizes to obtain the clamping force experimental data of the ring groove rivet of the test piece.

[0024] Step 6: Continue to insert a positioning nut, a pull-out push plate, a second pull-out fixture, a first axial force sensor, a second pull-out fixture, and a positioning nut into the outer end of the long screw thread and fix them in sequence. Align the piston ends of the two sets of hydraulic cylinders with the pull-out push plate to form a pull-out force test connection.

[0025] Step 7: Start the hydraulic pump station. The two hydraulic cylinders work simultaneously to push outwards, driving the pull-out push plate to move horizontally and pushing the long screw to move horizontally until the test piece's annular groove rivet is completely separated from the collar. Record the maximum value of the axial force sensor one to obtain the experimental data of the pull-out force of the test piece's annular groove rivet.

[0026] Step 8: Complete the mechanical property test of the ring groove rivet for the test piece; for the new test piece ring groove rivet, replace the dovetail groove connecting tooling and riveting bracket plate with the appropriate one and repeat steps one to seven.

[0027] The comprehensive experimental platform for the mechanical properties of ring groove rivets of the present invention has the following advantages:

[0028] The experimental platform of this invention can complete various mechanical and physical property tests such as clamping force and pull-out force in one go through a set of ring groove rivet connection pairs, which saves more on the cost of experimental samples.

[0029] The experimental platform of this invention completes the clamping force and pull-out force performance tests with a single device. During the experiment, there is no need to move the test equipment back and forth, avoiding the situation where multiple devices such as riveting pump stations, axial force sensors, and tensile testing machines need to work together. The labor intensity of the experimenters is reduced, the risk of injury from falling heavy objects is avoided, and the experiment time is saved, which can effectively improve the experimental efficiency.

[0030] The experimental platform of this invention transforms the overall structure of the grooved rivet, experimental fixture, axial force sensor, experimental fixture, and collar into a structure consisting of the grooved rivet, experimental fixture, fixture clearance, experimental fixture, and collar through the long screw on the comprehensive experimental platform for the mechanical properties of the grooved rivet. This significantly reduces the minimum connection thickness requirement for the clamping force test of the grooved rivet, meeting the national standard requirement that all grooved rivet connection pairs with a connection thickness of not less than twice the nominal diameter must undergo clamping force and pull-out force tests.

[0031] The experimental platform of this invention features a detachable structure design, making it easy to replace easily damaged and consumable parts. Furthermore, by replacing the dovetail groove connecting fixtures and riveting support plates, it can adapt to changes in the size of ring groove rivets, thus meeting the mechanical performance testing requirements of the entire M6 to M64 series of ring groove rivets.

[0032] The tooling on both sides of the sensor in this invention adopts a square or circular shape, with the side diameter being larger than the diameter of the sensor and the thickness being comparable to the diameter of the test ring groove rivet. This ensures that the pressure surface of the sensor is fully pressure-bearing and does not deform during the pressure process, resulting in more accurate experimental results.

[0033] The experimental platform of this invention is connected to the dovetail groove of the extended screw and the dovetail groove connecting fixture. During the test, the dovetail groove connecting fixture and the riveting bracket plate are guaranteed to have an installation gap. After installation, the clamping force of the ring groove rivet is transmitted to the second axial force sensor through the extended threaded rod, ensuring that the clamping force test can be completed for ring groove rivets with a length of twice the nominal diameter or more, and the experimental data is accurate.

[0034] The clamping force test fixture of this invention consists of an extended threaded rod, a dovetail groove connecting fixture, and a riveting support plate. The extended threaded rod and the dovetail groove connecting fixture are connected by mutually cooperating dovetail grooves. When conducting tests on ring groove rivets of different diameters, the test fixture can be quickly changed, improving experimental efficiency.

[0035] After conventional ring groove rivet riveting is completed, the entire set of test fixtures needs to be transferred to a tensile testing machine to complete the pull-out force test. The optimized fixture of the test bench of this invention uses two hydraulic cylinders to directly pull out the rivet, and the maximum data during the pull-out process is measured by an axial force sensor to complete the pull-out force test.

[0036] The experimental platform of this invention features arc-shaped pads at the bottom of the hydraulic cylinder and riveting tools to ensure that the center lines of the riveting gun, hydraulic cylinder, and rivet coincide, thus improving the accuracy of experimental data. All tooling on the upper part of the experimental platform is designed with lifting lugs for easy replacement according to experimental requirements. The display of the experimental platform integrates the related systems of the hydraulic pump station, axial force sensor one, and axial force sensor two, allowing operation and reading of relevant experimental data on a single display. Attached Figure Description

[0037] Figure 1 This is a top view schematic diagram of the test bench for the mechanical properties of the ring groove rivet of the present invention.

[0038] Figure 2 This is a front view schematic diagram of the test bench for the mechanical properties of the ring groove rivet of the present invention.

[0039] Figure 3 This is a schematic diagram of the clamping force test on the mechanical performance test bench for the ring groove rivet of the present invention.

[0040] Figure 4 This is a schematic diagram of the pull-out force test on the mechanical performance test bench for the ring groove rivet of the present invention.

[0041] Figure 5 It is a component structure of existing conventional clamping force testing.

[0042] Figure 6 This invention relates to a clamping force test and detection component structure.

[0043] Figure 7 This is a schematic diagram of the fixture for connecting the fixed support plate and the dovetail groove of the present invention.

[0044] In the diagram, 1 is a long screw, 2 is a positioning nut, 3 is a pull-out fixture one, 4 is an axial force sensor one, 5 is a pull-out fixture two, 6 is a pull-out push plate, 7 is a hydraulic cylinder, 8 is a positioning base, 9 is a fixed support plate, 10 is a clamping fixture one, 11 is an axial force sensor two, 12 is a clamping fixture two, 13 is a support leg, 14 is a dovetail groove connecting fixture, 15 is a riveting support plate, 16 is a ring groove rivet, 17 is a riveting tool, 18 is a display, 19 is a storage cabinet, and 20 is a roller; L1 is the standard rivet connection length, L2 is the rivet connection length of this experimental platform, L3 is the distance between the fixed support plate and the dovetail groove connecting fixture, and L4 is the exposed length of the rivet. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments. These specific embodiments are further explanations of the principles of the present invention and are not intended to limit the present invention in any way. Any technology that is the same as or similar to the present invention does not exceed the scope of protection of the present invention.

[0046] Referring to the accompanying drawings, the mechanical performance test bench for grooved rivets of the present invention is used to test the clamping force and pull-out force of grooved rivets. The test bench consists of a long screw 1, a positioning nut 2, a pull-out fixture 1 3, an axial force sensor 1 4, a pull-out fixture 2 5, a pull-out push plate 6, a hydraulic cylinder 7, a positioning base 8, a fixed support plate 9, a clamping fixture 1 10, an axial force sensor 2 11, a clamping fixture 2 12, a support leg 13, a dovetail groove connecting fixture 14, a riveting support plate 15, a grooved rivet 16, a riveting tool 17, a display 18, a storage cabinet 19, and rollers 20.

[0047] The experimental principle is as follows: during clamping force testing, the clamping force of the grooved rivet 16 is transmitted to the axial force sensor 11 via the long screw 1 for measurement. During pull-out force testing, the pull-out force of the grooved rivet 16 is transmitted to the axial force sensor 4 via the long screw 1 for measurement. The clamping force and pull-out force of the grooved rivet are transmitted to different sensors via the long screw 1 to achieve measurement. The clamping force and pull-out force tests can be completed through a set of grooved rivet connecting pairs.

[0048] The clamping force detection system is composed of the long screw 1, positioning nut 2, fixed bracket plate 9, clamping fixture 10, axial force sensor 2 11, clamping fixture 2 12, bracket leg 13, dovetail groove connecting fixture 14, and riveting bracket plate 15. The pull-out force detection system is composed of the long screw 1, positioning nut 2, pull-out fixture 1 3, axial force sensor 1 4, pull-out fixture 2 5, pull-out push plate 6, hydraulic cylinder 7, positioning base 8, fixed bracket plate 9, bracket leg 13, dovetail groove connecting fixture 14, and riveting bracket plate 15. The two systems are connected by the long screw 1.

[0049] As shown in the figure, the experimental platform features a detachable structure, facilitating the replacement of easily damaged and consumable parts. Furthermore, it can adapt to varying rivet sizes by replacing the dovetail groove connecting fixture 14 and the riveting support plate 15, thus meeting the mechanical performance testing requirements for the entire range of M6 to M64 ring groove rivets. The dovetail groove structure allows the movable dovetail groove connecting fixture 14 to be removed from the system via an embedded method, enabling the tested rivet specimens to be emptied and new specimens inserted, ensuring the sustainability of the testing.

[0050] The tooling on both sides of the sensor adopts a square or circular shape design, and the side length or diameter is larger than the diameter of the sensor. The thickness is equivalent to the diameter d of the test fastener ring groove rivet 16, which ensures that the pressure surface of the sensor is fully pressure-bearing and does not deform during the pressure process, resulting in more accurate experimental results.

[0051] Large-range sensors are generally quite thick to ensure measurement accuracy. Directly using these sensors for clamping force measurement does not meet the requirement of GB / T 36993 that clamping force tests must be conducted on all ring groove rivet connections with a connection thickness of not less than twice the nominal diameter. This invention's ring groove rivet mechanical performance testing bench integrates conventional ring groove rivets, testing fixtures, axial force sensors, and collar testing components into a single structure. Figure 5 As shown, the entire set of conventional ring groove rivet connection length L1 is transformed into a test and inspection component structure consisting of a long screw, positioning nut, experimental fixture, sensor, test fixture, rivet, dovetail groove, fixture clearance, test fixture, and collar. The thickness of the sensor is omitted from the rivet connection section, as shown. Figure 6 The test bench shown has a ring groove rivet connection length L2, which significantly reduces the minimum connection thickness requirement for the ring groove rivet clamping force test. This meets the national standard requirement that all ring groove rivet connection pairs with a connection thickness of not less than twice the nominal diameter must undergo clamping force and pull-out force tests.

[0052] The test bench of the present invention is connected to the dovetail groove of the extended screw 1 and the dovetail groove connecting fixture 14. During the test, there must be an installation gap between the dovetail groove connecting fixture 14 and the riveting bracket plate 15, and they cannot contact each other, so as to ensure that the clamping force after installation is transmitted to the sensor through the long screw 1.

[0053] The distance L3 between the fixed support plate 9 and the dovetail groove connecting fixture 14 of the test bench of the present invention is required to be greater than the exposed length L4 of the annular groove rivet 16, so as to ensure that the annular groove rivet 16 and the collar 17 can be completely separated during the pull-out force test.

[0054] Using the experimental platform of this invention, clamping force and pull-out force experiments were performed on the same equipment using the following method. The specific steps are as follows.

[0055] Step 1: Pass the test piece ring groove rivet 16 through the center hole of the dovetail groove connecting fixture 14;

[0056] Step 2: Fit the dovetail groove connecting fixture 14 with the test piece ring groove rivet 16 into the T-shaped connector of the long screw 1, and then insert the other end of the long screw 1 into the fixed bracket plate 9.

[0057] Step 3: Insert the tail of the ring groove rivet 16 into the riveting bracket plate 15 and the collar in sequence; place the L-shaped support leg 13 parallel between the fixed bracket plate 9 and the riveting bracket plate 15; adjust the position of the collar and ensure the gap between the dovetail groove connecting tool 14 and the riveting bracket plate 15 so that the dovetail groove connecting tool 14 and the riveting bracket plate 15 form a non-contact structure.

[0058] Step 4: Sequentially install clamping fixture 2 12, axial force sensor 2 11, and clamping fixture 1 10 onto the threaded end of the long screw 1. Screw in a positioning nut 2. Adjust the position of the positioning nut 2 to form a clamping force test connection body with the long screw 1, clamping fixture 1 10, axial force sensor 2 11, clamping fixture 2 12, fixed bracket plate 9, dovetail groove connecting fixture 14, riveting bracket plate 15, and test annular groove rivet 16.

[0059] Step 5: Connect the riveting tool 17 with the ring groove rivet 16 to prepare for extrusion riveting. Start the riveting tool 17 to complete the installation of the ring groove rivet 16. Record the data after the axial force sensor 11 stabilizes to obtain the clamping force experimental data of the ring groove rivet 16 of the test piece.

[0060] Step 6: Continue to insert a positioning nut 2, a pull-out push plate 6, a second pull-out fixture 5, an axial force sensor 4, a first pull-out fixture 3, and the positioning nut 2 into the outer end of the thread of the long screw 1 in sequence and fix them. Align the piston ends of the two sets of hydraulic cylinders 7 with the pull-out push plate 6 in parallel to form a pull-out force test connection.

[0061] Step 7: Start the hydraulic pump station. The two hydraulic cylinders 7 work simultaneously to push outwards, driving the pull-out push plate 6 to move horizontally and pushing the long screw 1 to move horizontally until the test piece annular groove rivet 16 is completely separated from the collar. Record the maximum value of the axial force sensor 4 to obtain the pull-out force experimental data of the test piece annular groove rivet 16.

[0062] Step 8: Complete the mechanical property test of the ring groove rivet of the test piece.

[0063] The clamping force and pull-out force tests of the existing grooved rivets were conducted separately.

[0064] The existing mechanical physical property test steps for clamping force include: (1) Connect the hydraulic pump station and special riveting tools to the position and check for any abnormalities; connect the axial force sensor and the numerical display to the position and check for any abnormalities. (2) Insert the grooved rivet into the test fixture, axial force sensor, and test fixture in sequence. The number of test fixtures can be increased according to the connection thickness range of the grooved rivet. Then screw the collar into the grooved rivet and wait for riveting. (3) Install the grooved rivet connection pair in place using the hydraulic pump station and special riveting tools. Then read the clamping force value through the display of the axial force sensor to obtain the clamping force test data of the grooved rivet connection pair and record it. (4) Move the riveted grooved rivet connection pair, axial force sensor, and multiple sets of test fixtures to a large tensile testing machine. Pull out or press out the rivet and collar axially, remove the axial force sensor and test fixture, and carry out the next test in a cycle.

[0065] The mechanical and physical property test of pull-out force of existing grooved rivets includes: (1) Connecting the hydraulic pump station and special riveting tools into place and checking for any abnormalities. (2) Inserting the grooved rivets into the test fixtures in sequence, where the number of test fixtures is determined according to the connection thickness range of the grooved rivets, and then screwing the collar into the grooved rivets and waiting for riveting. (3) Installing the grooved rivet connection pair into place using the hydraulic pump station and special riveting tools. (4) Moving the riveted grooved rivet connection pair and multiple sets of test fixtures as a whole to a large tensile testing machine, axially pulling out or pressing out to separate the rivets and collars, recording the pull-out force data, removing the test fixtures, and carrying out the next test in a cycle.

[0066] Existing clamping force and pull-out force tests have the following drawbacks: First, the experimental procedures are cumbersome. The entire test can take 5 to 15 minutes, depending on the specifications of the grooved rivets, resulting in low work efficiency and failing to meet the experimental schedule for mass production. Second, the weight of the riveted grooved rivet connection pair, axial force sensor, and multiple sets of experimental fixtures can range from 10 kg to 50 kg, depending on the specifications of the grooved rivets. This results in high labor intensity for test personnel during movement, the risk of injury from falling heavy objects, and the need for at least two people to work together, leading to high labor costs. Third, the clamping force test requires the destruction of a set of grooved rivets. For rivet connections, the pull-out force test requires destroying a set of annular groove rivet connections, resulting in high testing costs. Fourth, to ensure that all annular groove rivet connections with a connection thickness of not less than twice the nominal diameter are subject to clamping force testing as stipulated by national standards, an extra-large axial force sensor is required, along with a specially designed recessed testing fixture. This fixture is placed inside the sensor's inner hole to achieve the requirement that all annular groove rivet connections with a connection thickness of not less than twice the nominal diameter be subject to clamping force testing. Such a large axial force sensor is larger and heavier, leading to lower labor intensity and testing efficiency.

Claims

1. A mechanical property testing bench for grooved rivets, used for testing the clamping force and pull-out force of grooved rivets; characterized in that: It consists of the following components set on a platform; A long screw, with a T-shaped connector at one end and external threads on the shaft; A support includes: a planar fixed support plate with a central opening for a long screw to pass through freely; two sets of L-shaped support legs arranged in parallel, with the L-shaped feet supporting and fixing the plate surface during testing; and a planar riveting support plate with a central opening for a ring groove rivet to pass through freely, with its two ends supporting and fixing the other ends of the two support legs respectively during testing. Two sets of hydraulic cylinders are fixed parallel to each other on the platform surface, and their rear ends are supported and connected to the other side of the fixed bracket plate. A pull-out push plate, which is a planar structure, allows for separable contact between the two ends of the planar pull-out push plate and the pistons of two sets of hydraulic cylinders during testing. Both sets of pull-out fixtures are flat pads with a central hole for the long screw to pass through freely; both sets of clamping fixtures are flat pads with a central hole for the long screw to pass through freely. Two sets of axial force sensors; one axial force sensor is mounted on the long screw for pull-out force detection, and is installed between two sets of pull-out fixtures. The outer end of the pull-out fixture is fixed by a positioning nut, and the inner end of the pull-out fixture is in contact with the pull-out push plate; the second axial force sensor is mounted on the long screw for clamping force detection, and is installed between two sets of clamping fixtures. The outer end of the clamping fixture is fixed by a positioning nut, and the inner end of the clamping fixture is in contact with the fixed bracket plate of the bracket. A dovetail groove connecting fixture has a T-shaped dovetail groove with an embedded structure that can be detachably connected to a long screw T-shaped connector. A through hole is provided at the center of the bottom of the dovetail groove for the insertion and fixing of a ring groove rivet for inspection.

2. The mechanical performance test bench for ring groove rivets according to claim 1, characterized in that: The flat pads that make up the two sets of pull-out fixtures and the two sets of clamping fixtures are square or circular planes, with their side length or diameter being larger than the diameter of the axial force sensor, so that the two planes of the axial force sensor are fully covered.

3. The mechanical property test bench for ring groove rivets according to claim 1, characterized in that: The hydraulic cylinder and riveting tool are both fixed to the platform by arc-shaped pads, and the central axis of the riveting tool and the hydraulic cylinder is parallel to the central axis of the rivet.

4. The mechanical performance test bench for ring groove rivets according to claim 1, characterized in that: The two sets of hydraulic cylinders are fixed by two positioning bases fixed to the platform. The front ends of the two positioning bases are the positioning positions of the fixed support plate and are combined with the limiting position of the fixed support plate.

5. The mechanical performance test bench for ring groove rivets according to claim 1, characterized in that: The distance between the fixed bracket plate and the dovetail groove connecting fixture is greater than the exposed length of the annular groove rivet.

6. A method for testing the mechanical properties of a grooved rivet, characterized in that: The mechanical property testing bench for ring groove rivets according to any one of claims 1 to 5 includes the following steps: Step 1: Pass the test piece ring groove rivet through the center hole of the dovetail groove connecting tool; Step 2: Fit the dovetail groove connecting fixture with the test piece ring groove rivet into the long screw T-shaped connector, and then insert the other end of the long screw into the fixed bracket plate; Step 3: Insert the tail of the ring groove rivet into the riveting bracket plate and the collar in sequence; place the L-shaped support leg parallel between the fixed bracket plate and the riveting bracket plate; adjust the position of the collar and ensure the gap between the dovetail groove connecting tool and the riveting bracket plate so that the dovetail groove connecting tool and the riveting bracket plate form a non-contact structure. Step 4: Install clamping fixture 2, axial force sensor 2, and clamping fixture 1 sequentially onto the threaded end of the long screw. Screw in a positioning nut. Adjust the position of the positioning nut to form a clamping force test connection body with clamping fixture 1, axial force sensor 2, clamping fixture 2, fixed bracket plate, dovetail groove connecting fixture, riveting bracket plate, and test annular groove rivet. Step 5: Connect the riveting tool with the ring groove rivet collar to prepare for extrusion riveting. Start the riveting tool to complete the installation of the ring groove rivet. Record the data after the axial force sensor II stabilizes to obtain the clamping force experimental data of the ring groove rivet of the test piece. Step 6: Continue to insert a positioning nut, a pull-out push plate, a second pull-out fixture, a first axial force sensor, a second pull-out fixture, and a positioning nut into the outer end of the long screw thread and fix them in sequence. Align the piston ends of the two sets of hydraulic cylinders with the pull-out push plate to form a pull-out force test connection. Step 7: Start the hydraulic pump station. The two hydraulic cylinders work simultaneously to push outwards, driving the pull-out push plate to move horizontally and pushing the long screw to move horizontally until the test piece's annular groove rivet is completely separated from the collar. Record the maximum value of the axial force sensor one to obtain the experimental data of the pull-out force of the test piece's annular groove rivet. Step 8: Complete the mechanical property test of the ring groove rivet for the test piece; for the new test piece ring groove rivet, replace the dovetail groove connecting tooling and riveting bracket plate with the appropriate one and repeat steps one to seven.

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