Suspension type bidirectional three-point bending fatigue test clamp

Abstract

The invention belongs to the technical field of test fixtures, and provides a suspension type bidirectional three-point bending fatigue test fixture which comprises a base, and a test piece clamping groove is formed in the base; the two sets of suspension blocks are arranged at the two ends of the test piece clamping groove, magnetic suspension assemblies are arranged between the suspension blocks and the test piece clamping groove, and the magnetic suspension assemblies are used for enabling the suspension blocks to suspend in the test piece clamping groove; the two sets of bearing clamping modules are detachably connected to the opposite side walls of the two suspension blocks respectively, each bearing clamping module comprises an open bearing mechanism detachably connected to the corresponding suspension block, a test piece clamping module is hinged to the interior of each open bearing mechanism, and the two test piece clamping modules are used for clamping the two ends of a test piece respectively. According to the invention, when the test piece is subjected to a fatigue test, the support boundary still has certain sliding degree of freedom and rotational degree of freedom after being clamped.

Description

Technical Field

[0001] The invention belongs to the technical field of test fixtures, and in particular relates to a suspended bidirectional three-point bending fatigue test fixture. Background Art

[0002] With the popularity of steel structure bridges, more and more fatigue failure problems under bidirectional reciprocating deformation have appeared in engineering projects, and it is urgent to carry out bidirectional three-point bending fatigue tests. However, under the current mature technical means, bidirectional three-point bending fatigue tests generally use fixed clamping boundaries. This fixture and the specimen form an over-static system with large internal forces. If the expected test results are to be obtained, two measures must be taken: on the one hand, the cross-sectional thickness of the specimen support needs to be increased to reduce the possibility of failure of the clamping section; on the other hand, the loading efficiency of the effective test site needs to be improved through optimized design, resulting in high test costs. If a non-fastened support fixture is used to imitate the traditional unidirectional three-point bending, there will be problems of fixture wear and test noise for bidirectional reciprocating loading. Summary of the invention

[0003] The purpose of the present invention is to provide a suspended bidirectional three-point bending fatigue test fixture to solve the above-mentioned problem and achieve the purpose of enabling the specimen support boundary to still have a certain degree of sliding freedom and rotational freedom after being clamped.

[0004] To achieve the above object, the present invention provides the following solution: a suspended bidirectional three-point bending fatigue test fixture, comprising:

[0005] A base, wherein a specimen clamping groove is provided in the base;

[0006] Two groups of suspension blocks, the two groups of suspension blocks are arranged at both ends of the specimen clamping groove, a magnetic suspension component is arranged between the suspension blocks and the specimen clamping groove, and the magnetic suspension component is used to suspend the suspension blocks in the specimen clamping groove;

[0007] Two groups of bearing clamping modules, the two groups of bearing clamping modules are respectively detachably connected to the opposite side walls of the two suspension blocks, the bearing clamping modules include an open bearing mechanism detachably connected to the suspension block, a specimen clamping module is hinged in the open bearing mechanism, and the two specimen clamping modules are respectively used to clamp the two ends of the specimen.

[0008] Preferably, the open bearing mechanism includes an outer open bearing ring, an inner wall of which is provided with a plurality of ball grooves, a plurality of balls being rotatably connected in the plurality of ball grooves, an inner side of the outer open bearing ring being detachably connected with an inner open bearing ring, the inner open bearing ring being coaxially arranged with the outer open bearing ring, and an outer wall of the inner open bearing ring being in contact with the plurality of balls, an opening on a side wall of the outer open bearing ring being arranged corresponding to an opening on a side wall of the inner open bearing ring, and the specimen clamping module being arranged in the inner open bearing ring.

[0009] Preferably, a circular open through groove is provided between two opposite side walls of the suspension block, the circular open through groove is arranged on a side of the suspension block away from the specimen clamping groove, and an opening is provided on a side of the circular open through groove away from the specimen clamping groove, the specimen passes through the opening of the side wall of the circular open through groove, the opening of the side wall of the outer open bearing ring and the opening of the side wall of the inner open bearing ring in sequence, and corresponds to the specimen clamping module, and the outer open bearing ring and the circular open through groove are detachably connected via a spline structure.

[0010] Preferably, it further includes two groups of outer baffles, the edges of the outer baffles are fixedly connected with a plurality of fixing ears, the two opposite side walls of the suspension block are respectively provided with a plurality of fixing grooves, a plurality of the fixing grooves are arranged at the edges of the circular opening through-slot, a plurality of the fixing grooves are respectively provided with a first threaded hole, the two outer baffles are respectively detachably connected to the two ends of the circular opening through-slot through the fixing ears and the fixing grooves, and the two outer baffles are respectively fitted with the two ends of the outer opening bearing ring.

[0011] Preferably, the specimen clamping module includes a support frame, one end of the support frame is fixedly connected to the inner wall of the inner open bearing ring, and the other end of the support frame is respectively fixedly connected to a threaded hole end block and a through hole end block, the threaded hole end block and the through hole end block are coaxially arranged, and the axes of the threaded hole end block and the through hole end block are arranged close to the opening of the inner open bearing ring, a clamping plate is hinged between the threaded hole end block and the through hole end block through a quick-release shaft, and a clamping member is arranged on the clamping plate.

[0012] Preferably, the quick-release shaft includes a pin, one end of which is a threaded end and the other end is provided with a hexagonal head, the clamping plate is provided with a through hole at one end close to the support frame, the threaded end of the pin sequentially passes through the through hole end block and the through hole and is threadedly connected to the threaded hole end block.

[0013] Preferably, the clamping member includes a plurality of sliding grooves opened on the side of the clamping plate away from the support frame, a plurality of the sliding grooves are vertically arranged to the quick-release shaft, two groups of clamping blocks are slidably connected between the plurality of sliding grooves, a bidirectional screw is rotatably connected in the clamping plate, and the two groups of clamping blocks are respectively transmission-connected to the two ends of the bidirectional screw.

[0014] Preferably, both ends of the two groups of clamping blocks are respectively fixedly connected with locking ears, and the two locking ears on the same side of the two clamping blocks are fixedly connected by bolts and nuts.

[0015] Preferably, the specimen clamping groove includes a fixing groove opened on the suspension block, and suspension grooves are respectively opened inwardly on two opposite side walls of the fixing groove. The two suspension blocks are respectively arranged in the two suspension grooves, and the magnetic suspension assembly is arranged between the suspension grooves and the suspension blocks.

[0016] Preferably, the magnetic levitation assembly includes a plurality of electromagnets, which are respectively arranged at the top and bottom of the suspension tank, and the top and bottom of the suspension block are respectively fixedly connected with a plurality of magnets, and the plurality of magnets at the top and bottom of the suspension block are respectively arranged corresponding to the plurality of electromagnets at the top and bottom of the suspension tank.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: the main function of the magnetic suspension assembly is to suspend the suspension block in the specimen clamping groove during the test, and the end of the specimen has sliding freedom through the sliding of the suspension block in the specimen clamping groove; the main function of the open bearing mechanism is to enable the end of the specimen to be clamped on the specimen clamping module, and at the same time, the end of the specimen has rotational freedom by driving the specimen clamping module to rotate; the main function of the specimen clamping module is to clamp the end of the specimen to achieve the connection between the specimen and the fatigue testing machine. On the whole, when the clamp of the present invention is used to perform a two-way three-point bending test on the specimen, while firmly clamping the end of the specimen, the boundary of the specimen can have a certain sliding freedom and rotational freedom, avoiding the situation where there is a large internal force between the clamp and the specimen due to the formation of an over-static system during the test, improving the accuracy of the test results, and at the same time, effectively reducing the wear of the mold and reducing the test noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 is a schematic diagram of the clamp of the present invention;

[0020] Figure 2 is a schematic diagram of a suspension block of the present invention;

[0021] Figure 3 This is a schematic diagram of the suspension block of the present invention without the outer baffle;

[0022] Figure 4 is a schematic diagram of a bearing clamping module of the present invention;

[0023] Figure 5 is a schematic diagram of an open bearing mechanism of the present invention;

[0024] Figure 6 is a schematic diagram of a support frame of the present invention;

[0025] Figure 7 is a schematic diagram of an inner opening bearing ring of the present invention;

[0026] Figure 8 is a schematic diagram of a clamping member of the present invention;

[0027] Fig. 9 The circuit diagram of the magnetic suspension assembly of the present invention;

[0028] Among them, 1. base; 2. suspension block; 3. rubber pad; 4. magnet; 5. electromagnet; 6. bearing clamping module; 7. fixing groove; 8. suspension groove; 9. outer baffle plate; 10. inner baffle plate; 11. spline groove; 12. fixing ear piece; 13. first threaded hole; 14. fixing groove; 15. outer open bearing ring; 16. inner open bearing ring; 17. ball groove; 18. support frame; 19. clamping plate; 20. pin shaft; 21. clamping block; 22. extension plate; 23. locking ear piece; 24. spline; 25. threaded hole end block; 26. through hole end block; 27. second threaded hole; 28. fastening screw; 29. ​​through hole; 30. slide groove; 31. bidirectional screw; 32. circular open through groove; 33. ball. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Embodiment 1:

[0032] Reference Figure 1-Figure 8 The present invention provides a suspended bidirectional three-point bending fatigue test fixture, comprising:

[0033] A base 1, wherein a specimen clamping groove is provided in the base 1;

[0034] Two groups of suspension blocks 2, the two groups of suspension blocks 2 are arranged at both ends of the specimen clamping groove, and a magnetic suspension component is arranged between the suspension block 2 and the specimen clamping groove, and the magnetic suspension component is used to suspend the suspension block 2 in the specimen clamping groove;

[0035] Two sets of bearing clamping modules 6 are respectively detachably connected to the opposite side walls of the two suspension blocks 2. The bearing clamping modules 6 include an open bearing mechanism detachably connected to the suspension block 2. A specimen clamping module is hinged in the open bearing mechanism. The two specimen clamping modules are respectively used to clamp the two ends of the specimen.

[0036] The main function of the base 1 is to connect with the fatigue testing machine; the main function of the magnetic suspension assembly is to suspend the suspension block 2 in the specimen clamping groove during the test, and the end of the specimen has sliding freedom through the sliding of the suspension block 2 in the specimen clamping groove; the main function of the open bearing mechanism is to enable the end of the specimen to be clamped on the specimen clamping module, and at the same time, the end of the specimen has rotational freedom by driving the specimen clamping module to rotate; the main function of the specimen clamping module is to clamp the end of the specimen to achieve the connection between the specimen and the fatigue testing machine. On the whole, when the fixture of the present invention is used to perform a two-way three-point bending test on the specimen, while firmly clamping the end of the specimen, the boundary of the specimen can have a certain sliding freedom and rotational freedom, avoiding the situation where there is a large internal force between the fixture and the specimen due to the formation of an over-static system during the test, improving the accuracy of the test results, and at the same time, effectively reducing the wear of the mold and reducing the test noise.

[0037] A further optimized solution is provided, in which the open bearing mechanism comprises an outer open bearing ring 15, the inner wall of which is provided with a plurality of ball grooves 17, in which a plurality of balls 33 are rotatably connected respectively, the inner side of the outer open bearing ring 15 is detachably connected with an inner open bearing ring 16, the inner open bearing ring 16 is coaxially arranged with the outer open bearing ring 15, and the outer wall of the inner open bearing ring 16 is fitted with the plurality of balls 33, the opening of the side wall of the outer open bearing ring 15 is arranged corresponding to the opening of the side wall of the inner open bearing ring 16, and the specimen clamping module is arranged in the inner open bearing ring 16.

[0038] like Figure 5 As shown, the open ends of the outer open bearing ring 15 and the inner open bearing ring 16 are arranged on the same side, which can ensure that the end of the test piece extends into the inner open bearing ring 16, and at the same time, it can ensure that the inner open bearing ring 16 can rotate within a certain angle range in the outer open bearing ring 15.

[0039] A further optimized solution is provided, wherein a circular open slot 32 is provided between two opposite side walls of the suspension block 2, the circular open slot 32 is arranged on a side of the suspension block 2 away from the specimen clamping slot, and an opening is provided on the side of the circular open slot 32 away from the specimen clamping slot, the specimen passes through the opening of the side wall of the circular open slot 32, the opening of the side wall of the outer open bearing ring 15 and the opening of the side wall of the inner open bearing ring 16 in sequence, and is arranged corresponding to the specimen clamping module, and the outer open bearing ring 15 and the circular open slot 32 are detachably connected via a spline structure.

[0040] A further optimized solution is that the spline structure includes a plurality of spline grooves 11 opened on the inner wall of the circular open groove 32, and the plurality of spline grooves 11 are respectively arranged parallel to the axis of the circular open groove 32, and a plurality of splines 24 are fixedly connected to the outer wall of the outer open bearing ring 15, and the plurality of splines 24 are adapted to the plurality of spline grooves 11.

[0041] like Figure 1 , Figure 3 and Figure 5 As shown, the circular open slot 32 is provided with openings corresponding to the outer open bearing ring 15 and the inner open bearing ring 16, so as to ensure that after the specimen is fixed to the specimen clamping module, when it rotates within a certain angle range, it will not interfere with the opening edges of the suspension block 2, the outer open bearing ring 15 or the inner open bearing ring 16. The outer open bearing ring 15 can be quickly disassembled and assembled to the suspension block 2 through the spline 24 and the spline groove 11, so as to facilitate the disassembly and assembly of the specimen on the specimen clamping module.

[0042] A further optimized solution also includes two groups of outer baffles 9, and a plurality of fixing ears 12 are fixedly connected to the edges of the outer baffles 9. A plurality of fixing grooves 14 are respectively opened on the two opposite side walls of the suspension block 2. The plurality of fixing grooves 14 are arranged on the edges of the circular opening through groove 32. First threaded holes 13 are respectively arranged in the plurality of fixing grooves 14. The two outer baffles 9 are detachably connected to the two ends of the circular opening through groove 32 through the fixing ears 12 and the fixing grooves 14, and the two outer baffles 9 are respectively fitted with the two ends of the outer opening bearing ring 15.

[0043] like Figure 2 As shown, after the operator installs the outer open bearing ring 15 in the suspension block 2, the two outer baffles 9 are respectively buckled at the two ends of the circular open through groove 32, and the fixing ear piece 12 is placed in the fixing groove 14, and the fixing ear piece 12 is tightened in the first threaded hole 13 by bolts, so that the outer baffle 9 can be fixed to prevent the outer open bearing ring 15 from falling off.

[0044] A further optimization scheme also includes two groups of inner baffle plates 10, which are arranged at the two ends of the inner side of the outer open bearing ring 15, and the two groups of inner baffle plates 10 are respectively fitted with the two ends of the inner open bearing ring 16, and the inner side of the outer baffle plate 9 is fitted with the outer side of the inner baffle plate 10.

[0045] like Figure 2 and Figure 3 As shown, the operator places the inner open bearing ring 16 in the outer open bearing ring 15, and after placing the outer open bearing ring 15 in the circular open groove 32, first places the inner baffle plates 10 on both sides of the outer open bearing ring 15 and then installs the two outer baffle plates 9, so as to avoid axial displacement between the outer open bearing ring 15 and the inner open bearing ring 16.

[0046] A further optimized solution is provided, wherein the specimen clamping module comprises a support frame 18, one end of the support frame 18 is fixedly connected to the inner wall of the inner open bearing ring 16, and the other end of the support frame 18 is respectively fixedly connected to a threaded hole end block 25 and a through hole end block 26, the threaded hole end block 25 and the through hole end block 26 are coaxially arranged, and the axes of the threaded hole end block 25 and the through hole end block 26 are arranged close to the opening of the inner open bearing ring 16, a clamping plate 19 is hinged between the threaded hole end block 25 and the through hole end block 26 through a quick-release shaft, and a clamping member is arranged on the clamping plate 19.

[0047] like Figure 4 and Figure 6 As shown, the axes of the threaded hole end block 25 and the through hole end block 26 are in the same opening as the axis of the inner open bearing ring 16 and are arranged close to the opening. When the clamping plate 19 is pressed down at the end of the specimen, the clamping plate 19 can rotate counterclockwise around the quick-release shaft. At the same time, due to the aforementioned axis offset, the inner open bearing ring 16 will rotate clockwise driven by the support frame 18, which can smoothly realize the end deflection of the specimen, realize the rotational freedom, and minimize the influence of the rotation on the clamping member, thereby ensuring the clamping stability of the clamping member.

[0048] A further optimized solution is that the quick-release shaft includes a pin 20, one end of the pin 20 is a threaded end, and the other end is provided with a hexagonal head. A through hole 29 is provided at one end of the clamping plate 19 close to the support frame 18, and the threaded end of the pin 20 passes through the through hole end block 26 and the through hole 29 in sequence and is threadedly connected to the threaded hole end block 25.

[0049] like Figure 6 As shown, after the end of the specimen is clamped on the clamping plate 19, the clamping plate 19 is installed between the through hole end block 26 and the threaded hole end block 25, the pin 20 is passed through the through hole end block 26 and tightened in the threaded hole end block 25, so as to achieve the effect of hinged connection of the clamping plate 19 to the support frame 18.

[0050] A further optimized solution is that the clamping parts include a plurality of slide grooves 30 opened on the side of the clamping plate 19 away from the support frame 18, the plurality of slide grooves 30 are vertically arranged to the quick-release shaft, two groups of clamping blocks 21 are slidably connected between the plurality of slide grooves 30, a bidirectional screw 31 is rotatably connected in the clamping plate 19, and the two groups of clamping blocks 21 are respectively transmission-connected to the two ends of the bidirectional screw 31.

[0051] like Figure 8 As shown, one end of the bidirectional screw 31 is fixedly connected with a hexagonal head, and the specimen is placed between the two clamping blocks 21. The bidirectional screw 31 is rotated by the hexagonal head to move the two clamping blocks 21 toward the middle to clamp the specimen. The bidirectional screw 31 can make the moving distance of the two clamping blocks 21 the same, ensuring that after the specimen is clamped, its center position is in the same plane as the axis of the pin 20.

[0052] According to a further optimized solution, locking ears 23 are fixedly connected to both ends of the two groups of clamping blocks 21, and the two locking ears 23 on the same side of the two clamping blocks 21 are fixedly connected by bolts and nuts.

[0053] like Figure 8 As shown, the main function of the two locking ears 23 is to use the bolt and nut assembly to firmly lock the specimen between the two clamping blocks 21 after the clamping block 21 clamps the specimen stably, so as to prevent the specimen from falling off during the experiment.

[0054] A further optimized solution is that the specimen clamping groove includes a fixed groove 7 opened on the suspension block 2, and suspension grooves 8 are respectively opened inward on two opposite side walls of the fixed groove 7, the two suspension blocks 2 are respectively arranged in two suspension grooves 8, and the magnetic suspension component is arranged between the suspension groove 8 and the suspension block 2.

[0055] A further optimized solution is that the magnetic levitation assembly includes a plurality of electromagnets 5, which are respectively arranged at the top and bottom of the suspension tank 8, and a plurality of magnets 4 are respectively fixedly connected to the top and bottom of the suspension block 2, and the plurality of magnets 4 at the top and bottom of the suspension block 2 are respectively arranged corresponding to the plurality of electromagnets 5 at the top and bottom of the suspension tank 8.

[0056] Further optimization scheme, such as Figure 1 As shown, the electromagnets 5 are electrically connected to a suspension controller, which controls the magnitude of the magnetic force between the electromagnets 5 and the magnets 4 by controlling the magnitude of the current. During the experiment, the suspension block 2 is placed in a floating state by the magnetic force, and the two suspension blocks 2 can float within a certain range in the suspension tank 8 to achieve the floating of the end of the specimen.

[0057] In a further optimized solution, rubber pads 3 are respectively fixedly connected to the opposite side walls of the two suspension grooves 8. The main function of the rubber pads 3 is to prevent the suspension block 2 from moving too far in translation.

[0058] Embodiment 2:

[0059] The only difference between this embodiment and the first embodiment is that a plurality of slide grooves are provided on the inner wall of the inner open bearing ring 16, and the plurality of slide grooves are respectively arranged at the two ends of the opening of the inner open bearing ring 16, and extension pieces 22 are respectively slidably connected in the plurality of slide grooves, and a plurality of second threaded holes 27 are provided on the outer wall of the inner open bearing ring 16, and fastening screws 28 are respectively threadedly connected in the plurality of second threaded holes 27, and the plurality of fastening screws 28 are respectively arranged corresponding to the outer walls of the plurality of extension pieces 22.

[0060] like Figure 7 As shown, the operator can adjust the actual opening size of the inner open bearing ring 16 by moving a number of extension pieces 22 according to the movement range of the specimen in the opening of the inner open bearing ring 16 during the test. After the adjustment, the extension piece 22 is locked by tightening the fixing screw 28, thereby effectively preventing the specimen from swinging excessively in the inner open bearing ring 16 during the test, thereby improving the stability of the test process.

[0061] Embodiment three:

[0062] The schematic diagram of the magnetic levitation assembly is as follows Fig. 9 As shown, when working, the terminal first inputs the reference signal into the controller, and the controller controls a number of power amplifiers, which energize a number of electromagnets 5 on the upper and lower sides of the suspension block 2, so that the electromagnets 5 are magnetic, and the magnets 4 are pushed or attracted by magnetic force, so that the suspension block 2 is in a suspended state in the base 1. During the working process, the distance between the suspension block 2 and the base 1 is monitored by the displacement sensor, so as to judge the position of the suspension block 2 in the base 1. When the displacement sensor detects that the suspension block 2 is too high in the base 1 due to the force, the signal processor inputs a corresponding correction signal to the controller according to the signal monitored by the displacement sensor, and then the controller controls the power amplifier to adjust the magnetic size of the electromagnets 5 on the upper and lower sides, so as to achieve the stability of the position of the suspension block 2 in the base 1.

[0063] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0064] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A suspended bidirectional three-point bending fatigue test fixture, characterized in that: include: A base (1), wherein a specimen clamping groove is provided in the base (1); Two groups of suspension blocks (2), the two groups of suspension blocks (2) being arranged at two ends of the specimen clamping groove, a magnetic suspension component being arranged between the suspension blocks (2) and the specimen clamping groove, the magnetic suspension component being used to suspend the suspension blocks (2) in the specimen clamping groove; Two groups of bearing clamping modules (6), the two groups of bearing clamping modules (6) are respectively detachably connected to the opposite side walls of the two suspension blocks (2), the bearing clamping modules (6) include an open bearing mechanism detachably connected to the suspension block (2), a specimen clamping module is hinged in the open bearing mechanism, and the two specimen clamping modules are respectively used to clamp the two ends of the specimen.

2. A suspended bidirectional three-point bending fatigue test fixture according to claim 1, characterized in that: The open bearing mechanism comprises an outer open bearing ring (15), a plurality of ball grooves (17) are arranged on the inner wall of the outer open bearing ring (15), a plurality of balls (33) are rotatably connected in the plurality of ball grooves (17), an inner open bearing ring (16) is detachably connected to the inner side of the outer open bearing ring (15), the inner open bearing ring (16) is coaxially arranged with the outer open bearing ring (15), and the outer wall of the inner open bearing ring (16) is in contact with the plurality of balls (33), the opening of the side wall of the outer open bearing ring (15) is arranged corresponding to the opening of the side wall of the inner open bearing ring (16), and the specimen clamping module is arranged in the inner open bearing ring (16).

3. A suspended bidirectional three-point bending fatigue test fixture according to claim 2, characterized in that: A circular open slot (32) is provided between two opposite side walls of the suspension block (2); the circular open slot (32) is arranged on a side of the suspension block (2) away from the specimen clamping slot, and an opening is provided on a side of the circular open slot (32) away from the specimen clamping slot; the specimen passes through the opening of the side wall of the circular open slot (32), the opening of the side wall of the outer open bearing ring (15), and the opening of the side wall of the inner open bearing ring (16) in sequence, and is arranged corresponding to the specimen clamping module; the outer open bearing ring (15) and the circular open slot (32) are detachably connected via a spline structure.

4. A suspended bidirectional three-point bending fatigue test fixture according to claim 3, characterized in that: The invention also comprises two groups of outer baffles (9), the edges of the outer baffles (9) are fixedly connected with a plurality of fixing ears (12), two opposite side walls of the suspension block (2) are respectively provided with a plurality of fixing grooves (14), the plurality of fixing grooves (14) are arranged at the edges of the circular opening through groove (32), a first threaded hole (13) is respectively arranged in the plurality of fixing grooves (14), the two outer baffles (9) are respectively detachably connected to the two ends of the circular opening through groove (32) through the fixing ears (12) and the fixing grooves (14), and the two outer baffles (9) are respectively fitted with the two ends of the outer opening bearing ring (15).

5. The suspended bidirectional three-point bending fatigue test fixture according to claim 2 is characterized in that: The specimen clamping module comprises a support frame (18), one end of the support frame (18) is fixedly connected to the inner wall of the inner open bearing ring (16), and the other end of the support frame (18) is respectively fixedly connected to a threaded hole end block (25) and a through hole end block (26), the threaded hole end block (25) and the through hole end block (26) are coaxially arranged, and the axes of the threaded hole end block (25) and the through hole end block (26) are arranged close to the opening of the inner open bearing ring (16), and a clamping plate (19) is hinged between the threaded hole end block (25) and the through hole end block (26) through a quick-release shaft, and a clamping member is arranged on the clamping plate (19).

6. A suspended bidirectional three-point bending fatigue test fixture according to claim 5, characterized in that: The quick-release shaft comprises a pin shaft (20), one end of the pin shaft (20) is a threaded end, and the other end is provided with a hexagonal head. The end of the clamping plate (19) close to the support frame (18) is provided with a through hole (29), and the threaded end of the pin shaft (20) passes through the through hole end block (26) and the through hole (29) in sequence and is threadedly connected with the threaded hole end block (25).

7. The suspended bidirectional three-point bending fatigue test fixture according to claim 5, characterized in that: The clamping member comprises a plurality of slide grooves (30) which are arranged on a side of the clamping plate (19) away from the support frame (18); the plurality of slide grooves (30) are arranged vertically to the quick-release shaft; two groups of clamping blocks (21) are slidably connected between the plurality of slide grooves (30); a bidirectional screw rod (31) is rotatably connected in the clamping plate (19); and the two groups of clamping blocks (21) are respectively transmission-connected to the two ends of the bidirectional screw rod (31).

8. The suspended bidirectional three-point bending fatigue test fixture according to claim 7, characterized in that: The two ends of the two groups of clamping blocks (21) are respectively fixedly connected with locking ear pieces (23), and the two locking ear pieces (23) on the same side of the two clamping blocks (21) are fixedly connected by bolts and nuts.

9. The suspended bidirectional three-point bending fatigue test fixture according to claim 1, characterized in that: The specimen clamping groove comprises a fixing groove (7) provided on the suspension block (2), suspension grooves (8) are respectively provided inwardly on two opposite side walls of the fixing groove (7), the two suspension blocks (2) are respectively arranged in the two suspension grooves (8), and the magnetic suspension assembly is arranged between the suspension grooves (8) and the suspension blocks (2).

10. The suspended bidirectional three-point bending fatigue test fixture according to claim 9, characterized in that: The magnetic suspension assembly comprises a plurality of electromagnets (5), the plurality of electromagnets (5) being respectively arranged at the top and bottom of the suspension tank (8), the top and bottom of the suspension block (2) being respectively fixedly connected with a plurality of magnets (4), and the plurality of magnets (4) at the top and bottom of the suspension block (2) being respectively arranged corresponding to the plurality of electromagnets (5) at the top and bottom of the suspension tank (8).

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