A cylindrical specimen fatigue test loading device

Abstract

The present invention provides a columnar specimen fatigue test loading device, which belongs to the field of material testing devices, and includes: a load transfer member, a first limit end is arranged in the middle of its inner wall; a force member, the outer diameter of which matches the inner diameter of the load transfer member, and a second limit end is arranged on its inner wall; one end of the force member is detachably connected to the load transfer member, and the other end is provided with a through hole; the first limit end and the second limit end are both truncated cone structures with cavities; a clamping assembly, which includes two symmetrically arranged clamping blocks; when the clamping assembly is used, it is located between the load transfer member and the force member, and when a columnar specimen is clamped between the two clamping blocks, the two clamping blocks form a spindle-shaped structure, and at this time, the two side conical surfaces of the spindle-shaped structure formed by the two clamping blocks are respectively abutted against the inner walls of the first limit end and the second limit end. The device can ensure uniform stress distribution at the ends of the columnar specimens in fatigue tests, and avoid brittle failure caused by concentrated force at the ends of the columnar specimens.

Description

Technical Field

[0001] The invention belongs to the technical field of material testing devices, and in particular relates to a columnar sample fatigue test loading device. Background Art

[0002] Columnar steel structural members such as steel bars and cables are often used in bridge structures. In particular, threaded connections and rivet connections are often used in the connection of steel beams, steel columns, and steel trusses in steel bridge structures. Due to the long-term combined effects of alternating stress, corrosive environment, and material degradation, the above-mentioned structures are prone to fatigue failure accompanied by multi-factor damage coupling, which in turn affects the safety of the structure. Therefore, effectively evaluating the fatigue life of columnar specimens 7 under multi-factor coupling is an important guarantee for the safety and long-term operation and maintenance of bridge structures.

[0003] In the existing cylindrical specimen fatigue test, there are the following problems:

[0004] 1. The contact area between the traditional fatigue test loading device and the columnar specimen used in the test is too small, resulting in excessive local stress at the end of the columnar specimen and premature brittle failure, which in turn affects the fatigue test results. It is impossible to provide anchoring and reinforcement functions for the columnar specimen at the same time, and the traditional one-time pouring reinforcement method for the columnar specimen will cause waste of material processing.

[0005] 2. Under high-frequency alternating load environment, due to insufficient anchoring force between the fatigue test loading device and the columnar specimen used in the test and the self-locking characteristics of the threaded connection under unidirectional force, the connection between the fatigue test loading device and the columnar specimen is prone to loosening, resulting in the load applied by the fatigue testing machine being unable to be transmitted to the columnar specimen through the fatigue test loading device. Summary of the invention

[0006] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a columnar specimen fatigue test loading device.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A cylindrical specimen fatigue test loading device, comprising:

[0009] The load transfer member is a tubular structure, and a first limiting end is provided in the middle of the inner wall of the load transfer member;

[0010] The force-applying member is a tubular structure, and a second limiting end is provided on the inner wall; one end of the force-applying member is detachably connected to the load transfer member, and the other end is provided with a through hole; both the first limiting end and the second limiting end are truncated cone structures with cavities;

[0011] A clamping assembly, comprising two symmetrically arranged clamping blocks; when the clamping assembly is in use, it is located between the load transfer member and the force applying member, and when a columnar specimen is clamped between the two clamping blocks, the two clamping blocks form a spindle-shaped structure, and at this time, the two side conical surfaces of the spindle-shaped structure formed by the two clamping blocks respectively abut against the inner walls of the first limit end and the second limit end.

[0012] Preferably, the clamping surfaces of the two clamping blocks are provided with limiting grooves along the length direction.

[0013] Preferably, the outer wall of the force applying member is provided with an external thread;

[0014] The load transfer component includes a first pipe fitting and a second pipe fitting integrally formed with the first pipe fitting, the inner diameter of the first pipe fitting is larger than the inner diameter of the second pipe fitting; the inner wall of the first pipe fitting is provided with a first internal thread matching the load transfer end of the fatigue testing machine, the first limiting end is provided at an end of the inner wall of the second pipe fitting close to the first pipe fitting, and the end of the inner wall of the second pipe fitting away from the first pipe fitting is provided with a second internal thread matching the external thread of the force-applying component.

[0015] Preferably, a first hexagonal anchoring end is provided at the connecting end surface of the first pipe fitting and the second pipe fitting, and a second hexagonal anchoring end integrally formed with the force-applying member is provided at the end of the force-applying member located inwardly contracted from the second limiting end, and the second limiting end extends into the second hexagonal anchoring end, and the through hole is opened in the middle of the second hexagonal anchoring end.

[0016] Preferably, it also includes a rubber gasket and an anti-disturbance nut matching the force-applying member, the inner wall of the anti-disturbance nut is provided with a third internal thread matching the external thread of the force-applying member, and the surface of the anti-disturbance nut is rolled with a mesh knurling pattern.

[0017] Preferably, the two clamping blocks are cut from a spindle-shaped structural member, and when the spindle-shaped structural member is cut, the two clamping blocks are cut at a position above and below the plane where the neutral axis of the spindle-shaped structural member is located. Cutting is performed at parallel planes at the positions to form two clamping blocks;

[0018] Wherein, Δl is the distance between the cutting planes of the two clamping blocks, 0.5mm<Δl<1.2mm.

[0019] Preferably, the top half angle α of the clamping block is 0 The top half angle α between the first limiting end and the second limiting end 1 equal.

[0020] Preferably, the radius of the end of the first limiting end close to the first pipe and the end of the second limiting end located at the second hexagonal anchoring end are both d 1 ;

[0021] When cutting the spindle-shaped structure, both ends of the spindle-shaped structure are also cut vertically to form a circular surface, and the diameter of the circular surface is d 0 ;

[0022] and, α=α 0 =α 1 ;

[0023] Among them, α 0 is the top half angle of the clamp, α 1 is the top half angle of the first limiting end and the second limiting end, and 18°<α 0 <36°.

[0024] Preferably, the volume of the cavities inside the first limiting end and the second limiting end are both smaller than half the volume of the spindle-shaped structure formed by the two clamping blocks clamping the columnar sample;

[0025] The length l of the clamp 0 satisfy

[0026] Among them, l 1 is the length of the first limiting end and the second limiting end, l 1 and l 0 The unit is mm.

[0027] Preferably, the inner wall of the first limiting end and the outer surface of the clamping block are ground and polished surfaces, and both side surfaces of the rubber gasket are provided with linear raised patterns.

[0028] The columnar specimen fatigue test loading device provided by the present invention has the following beneficial effects:

[0029] The present invention is provided with a tubular load transfer member, a force member, and a clamping assembly of a spindle-shaped structure. The columnar sample can be clamped by the clamping assembly of the spindle-shaped structure, and the clamping assembly can be pre-tightened by the load transfer member and the force member, thereby achieving the purpose of tightening the columnar sample. The device can ensure uniform stress distribution at the end of the columnar sample during fatigue testing, and avoid brittle failure caused by concentrated force at the end of the columnar sample. At the same time, the geometric shape of the clamping assembly is optimized, and the outer surface of the clamping assembly is designed to be a bottom-conical shape, which increases the anchoring force between the loading device and the columnar sample used in the test, so that it will not loosen even in a high-frequency alternating load environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. 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 creative work.

[0031] Figure 1 A schematic diagram of the pre-installation of a columnar specimen fatigue test loading device provided in Example 1 of the present invention;

[0032] Figure 2 It is a schematic diagram of the pre-installation of the force-applying member;

[0033] Figure 3 is a structural schematic diagram of a load transfer member;

[0034] Figure 4 is a structural schematic diagram of a force-applying member;

[0035] Figure 5 is a schematic diagram of the structure of the clamping assembly;

[0036] Figure 6 is a cross-sectional schematic diagram of a load transfer member;

[0037] Figure 7 is a cross-sectional schematic diagram of a clamping assembly;

[0038] Figure 8 is a cross-sectional schematic diagram of a force-applying member;

[0039] Fig. 9 This is a front view of the rubber gasket;

[0040] Fig.10 Schematic diagram of the pre-installation of two sets of loading devices for the cylindrical specimen fatigue test loading test.

[0041] Description of reference numerals:

[0042] Load transfer component 1, first pipe fitting 11, second pipe fitting 12, first internal thread 13, second internal thread 14, first limiting end 2, force applying member 3, external thread 31, second limiting end 4, through hole 5, clamping assembly 6, clamping block 61, columnar specimen 7, limiting groove 8, first hexagonal anchor end 9, second hexagonal anchor end 10, rubber gasket 15, anti-disturbance nut 16, third internal thread 161. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0044] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention and simplifying the description, 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 cannot be understood as a limitation on the present invention.

[0045] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0046] Example 1

[0047] The present invention provides a columnar specimen fatigue test loading device, specifically Figures 1 to 4 As shown, it includes a load transfer member 1, a force applying member 3 and a clamping assembly 6, and the load transfer member 1 and the force applying member 3 are both tubular structures.

[0048] Specifically, a first limit end 2 is provided in the middle of the inner wall of the load transfer member 1, and a second limit end 4 is provided on the inner wall; one end of the force-applying member 3 is detachably connected to the load transfer member 1, and the other end is provided with a through hole 5 to ensure that the columnar specimen 7 of the steel structure can pass through; the first limit end 2 and the second limit end 4 are both truncated cone structures with a cavity.

[0049] like Figure 5 As shown, the clamping assembly 6 includes two symmetrically arranged clamping blocks 61. In order to increase the anchoring force between the clamping blocks 61 and the columnar specimen 7, the clamping blocks 61 are designed to be a bottom-conical shape. When the clamping assembly 6 is in use, it is located between the load transfer member 1 and the force-applying member 3. When the columnar specimen 7 is clamped between the two clamping blocks 61, the two clamping blocks 61 form a spindle-shaped structure. At this time, the two side conical surfaces of the spindle-shaped structure formed by the two clamping blocks 61 are respectively in contact with the inner walls of the first limit end 2 and the second limit end 4. The spindle shape is a shape with pointed ends and wide in the middle. It can also be understood as a three-dimensional structure formed by combining two cones with their bottom surfaces.

[0050] Specifically, in this embodiment, the clamping surfaces of the two clamping blocks 61 are provided with limiting grooves 8 along the length direction, and the geometric dimensions thereof should be equal to those of the anchored columnar specimens.

[0051] Specifically, in this embodiment, the outer wall of the force applying member 3 is provided with an external thread 31. Figure 3 As shown, in order to facilitate the application of preload at the threaded connection and meet the requirements of strength and repeated use, the load transfer component 1 includes a first pipe fitting 11 and a second pipe fitting 12 integrally formed with the first pipe fitting 11. The inner diameter of the first pipe fitting 11 is larger than the inner diameter of the second pipe fitting 12, that is, the inner diameters of the load transfer component 1 are not equal; the inner wall of the first pipe fitting 11 is provided with a first internal thread 13 matching the load transfer end of the fatigue testing machine, the first limiting end 2 is provided on the inner wall of the second pipe fitting 12 at one end close to the first pipe fitting 11, and the inner wall of the second pipe fitting 12 at one end away from the first pipe fitting 11 is provided with a second internal thread 14 matching the external thread 31 of the force applying member 3. In order to reduce the loosening of the threaded connection caused by high-frequency alternating loads, the second internal thread 14 can adopt a triangular thread with a short pitch.

[0052] When in use, the first internal thread 13 end of the first pipe 11 is threadedly connected to the load transfer end of the fatigue testing machine, and then one end of the columnar specimen 7 is passed through the through hole 5 of the force-applying member 3 and clamped between the two clamping blocks 61, and the columnar specimen 7 is embedded in the limiting groove 8 of the clamping block 61. At this time, one end of the spindle-shaped structure formed by the two clamping blocks 61 is inserted into the first limiting end 2, and the other end is inserted into the second limiting end 4. The first limiting end 2 and the second limiting end 4 are used to fix the two clamping blocks 61. Finally, the second internal thread 14 cooperates with the external thread 31 to screw the force-applying member 3 and the second pipe 12. During the screwing process, the two ends of the spindle-shaped structure are continuously squeezed by the first limiting end 2 and the second limiting end 4, and finally the clamping block 61 is continuously approached to tighten one end of the columnar specimen 7.

[0053] Specifically, in this embodiment, a first hexagonal anchoring end 9 is provided at the connecting end surface of the first pipe 11 and the second pipe 12, which is used to provide torque to the load transfer member 1. A second hexagonal anchoring end 10 integrally formed with the force applying member 3 is provided at one end of the force applying member 3 which is located at the inward contraction of the second limiting end 4, the second limiting end 4 extends into the second hexagonal anchoring end 10, and the through hole 5 is opened in the middle of the second hexagonal anchoring end 10.

[0054] In order to prevent high-frequency alternating loads from causing sudden changes in interface stress at the threaded connection and causing the threaded connection to loosen, an anti-disturbance nut 16 that cooperates with the force-applying member 3 is added. The inner wall of the anti-disturbance nut 16 is provided with a third internal thread 161 that matches the external thread 31 of the force-applying member 3. When in use, the anti-disturbance nut 16 is screwed onto the force-applying member 3. The thread parameters such as the outer diameter, inner diameter, and pitch of the third internal thread 161 of the anti-disturbance nut 16 should ensure that they are the same as the thread parameters of the external thread 31 of the force-applying member 3. The anti-disturbance nut 16 is used to increase the preload force at the threaded connection between the load transfer member 1 and the force-applying member 3. In order to increase the friction between the load transfer member 1 and the anti-disturbance nut 16, a self-locking rubber gasket 15 with a rough surface is added between the load transfer member 1 and the anti-disturbance nut 16 during use. Fig. 9 As shown, in order to increase the friction force on the surface of the self-locking rubber gasket 14, linear raised patterns with an angle of 60° clockwise to the symmetry axis can be set on both sides of the rubber gasket 15. The existence of the rubber gasket 15 also ensures that the anti-disturbance nut 16 is not easy to loosen; ultimately, it is not easy for the load transfer member 1, the force applying member 3 and the anti-disturbance nut 16 to have relative displacement with each other.

[0055] In order to increase the friction coefficient of the surface of the anti-disturbance nut, the surface of the anti-disturbance nut 16 is rolled with a mesh knurling pattern.

[0056] like Figures 6 to 8 As shown, in order to ensure that the anchoring force can be fully transmitted to the columnar specimen 7 when the two clamping blocks 6 are closed toward the middle, sufficient shrinkage space should be left between the two clamping blocks 6. Specifically, in this embodiment, the two clamping blocks 61 are cut from a spindle-shaped structural member. When the spindle-shaped structural member is cut, the plane above and below the neutral axis of the spindle-shaped structural member is provided with a plurality of Cutting is performed at the parallel planes at the positions to form two clamping blocks 61;

[0057] Wherein, Δl is the distance between the cutting planes of the two clamping blocks 61, 0.5 mm<Δl<1.2 mm.

[0058] Specifically, in this embodiment, the top half angle α of the first limiting end 2 and the second limiting end 4 is 1 To ensure that the surface of the clamping block 6 is in full contact with the second limiting end 4, the top half angle α of the clamping block 6 0 Should be consistent with the top half angle α 1 equal.

[0059] In order to increase the anchoring force between the limit groove 8 and the columnar specimen 7, the clamp block 6 is designed to be a bottom-conical shape. Compared with a single conical clamp block, the preload force at the connection between the second pipe 12 and the force-applying member 3 is the same, and the top half angle α is 1 Under the same conditions, the anchoring force of columnar specimen 7 is increased to nearly twice the original value.

[0060] Specifically, Figure 6 As shown, in this embodiment, the radius of the end of the first limiting end 2 close to the first pipe 11 and the end of the second limiting end 4 located at the second hexagonal anchoring end 10 are both d 1 .

[0061] As Figure 7 As shown, when cutting the spindle-shaped structure, the two ends of the spindle-shaped structure are also cut vertically to form a circular surface, and the diameter of the circular surface is d 0 .

[0062] To prevent the end plane of the clamp block 6 from contacting the load transfer member 1, the diameter d 0 ,d 1 Should meet α=α 0 =α 1 .

[0063] Among them, α 0 is the top half angle of the clamp 61, α 1 is the top half angle of the first limiting end 2 and the second limiting end 4, and 18°<α 0 <36°.

[0064] In order to prevent the clamp block 6 with the columnar sample 7 from being too small, which may result in the clamp block 6 being unable to close to the middle and generate anchoring force during the connection between the second pipe 12 and the force-applying member 3, it is necessary to ensure that the volume of the cavity inside the first limiting end 2 and the second limiting end 4 is less than half of the volume of the spindle-shaped structure formed by the two clamp blocks 61 with the columnar sample 7. If the volume of the cavity inside the first limiting end 2 and the second limiting end 4 is reduced blindly, the end length l of the clamp block 6 will be 0 Under the same condition, the length of the internal thread of the second pipe 12 increases, which not only increases the useless thread processing cost, but also reduces the strength of the load transfer member 1. Or if the volume of the clamp block 6 is increased blindly, it will lead to material waste, and at the same time, it will also lead to an increase in the length of the internal thread of the second pipe 12, increasing the processing cost. In order to meet the requirements of closing the clamp block 6 and saving material and processing costs, the end length l of the clamp block 6 is 0 Should meet:

[0065] Among them, l 1 is the length of the first limiting end 2 and the second limiting end 4, l 1 and l 0 The unit is mm.

[0066] In order to reduce the friction between the first limiting end 2 and the surface of the clamping block 6, the surfaces of the first limiting end 2 and the clamping block 6 may be subjected to super-fine grinding and polishing respectively.

[0067] When the columnar specimen fatigue test loading device provided in this embodiment is used for fatigue testing, two sets of loading devices are required, and the two sets of loading devices are arranged oppositely at the load transfer end of the fatigue testing machine, such as Fig.10 The specific installation process is as follows:

[0068] Step 1: Connect the two load transfer members 1 to the two load transfer ends of the fatigue testing machine respectively by twisting the first hexagonal anchor ends 9 of the two sets of loading devices clockwise.

[0069] Step 2: Pass one end of the columnar specimen 7 through the anti-disturbance nut 16, rubber gasket 15, and through hole 5 of force applying member 3 of one set of loading devices at one time. Pass the other end of the columnar specimen 7 through the anti-disturbance nut 16, rubber gasket 15, and through hole 5 of force applying member 3 of another set of loading devices at one time.

[0070] Step 3: Use two clamping blocks 61 to clamp the columnar sample 7 between the second pipe member 12 of the one-side loading device and the force-applying member 3 , and embed the columnar sample 7 into the limiting groove 8 of the clamping blocks 61 .

[0071] Step 4: insert one end of the spindle-shaped structure formed by the two clamping blocks 61 of the one side loading device into the first limiting end 2 and the other end into the second limiting end 4 . The first limiting end 2 and the second limiting end 4 are used to fix the two clamping blocks 61 .

[0072] Step 5, the second internal thread 14 cooperates with the external thread 31, and the second hexagonal anchor end 10 is screwed clockwise to screw the force member 3 and the second pipe fitting 12. During the screwing process, the two ends of the spindle-shaped structure are continuously squeezed by the first limit end 2 and the second limit end 4, and finally the clamping block 61 is closed to the plane where the neutral axis is located, and continuously approaches and tightens one end of the columnar specimen 7.

[0073] Step 6: Twist the anti-disturbance nut 16 clockwise to screw it onto the force-applying member 3, so that the rubber gasket 15 is in close contact with the end of the second pipe member 12, thereby completing the anchoring of one end of the columnar specimen.

[0074] Step 7: Repeat steps (3) to (6) to complete the anchoring of the other end of the columnar specimen.

[0075] The columnar specimen fatigue test loading device provided in this embodiment can ensure uniform stress distribution at the ends of the columnar specimens during fatigue tests, and avoid brittle failure caused by concentrated force at the ends of the columnar specimens. At the same time, the geometric shape of the clamp block is optimized, and the outer surface of the clamp block is designed to be a bottom-type cone, which increases the anchoring force between the loading device and the columnar specimen used in the test. The screw anchor connection structure is also optimized so that it will not loosen even in a high-frequency alternating load environment. The present invention has the characteristics of simple structure, small size, easy installation and disassembly, and easy replacement of clamp blocks. The device can significantly enhance the end anchoring force in the fatigue loading test of columnar specimens and avoid the problem of loose connection at the threaded connection caused by high-frequency alternating loads.

[0076] The embodiments described above are only preferred specific implementation modes of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belong to the protection scope of the present invention.

Claims

1. A cylindrical specimen fatigue test loading device, characterized in that: include: The load transfer member (1) is a tubular structure, and a first limiting end (2) is provided in the middle of the inner wall of the load transfer member (1); The force-applying member (3) is a tubular structure, and a second limiting end (4) is provided on the inner wall; one end of the force-applying member (3) is detachably connected to the load transfer member (1), and the other end is provided with a through hole (5); the first limiting end (2) and the second limiting end (4) are both truncated cone structures with cavities; A clamping assembly (6), comprising two symmetrically arranged clamping blocks (61); when in use, the clamping assembly (6) is located between the load transfer member (1) and the force application member (3); when a columnar specimen (7) is clamped between the two clamping blocks (61), the two clamping blocks (61) form a spindle-shaped structure, and at this time, the conical surfaces on both sides of the spindle-shaped structure formed by the two clamping blocks (61) respectively abut against the inner walls of the first limiting end (2) and the second limiting end (4); The two clamping blocks (61) are cut from a spindle-shaped structural member. When the spindle-shaped structural member is cut, the two clamping blocks (61) are cut at the upper and lower sides of the plane where the neutral axis of the spindle-shaped structural member is located. Cutting is performed at parallel planes to form two clamping blocks (61); Wherein, Δl is the distance between the cutting planes of the two clamping blocks (61), 0.5 mm < Δl < 1.2 mm; The top half angle α0 of the clamping block (61) is equal to the top half angle α1 of the first limiting end (2) and the second limiting end (4); The radii of the end of the first limiting end (2) close to the first pipe (11) and the end of the second limiting end (4) located at the second hexagonal anchoring end (10) are both d1; When cutting the spindle-shaped structure, two ends of the spindle-shaped structure are also vertically cut to form circular surfaces, and the diameter of the circular surface is d0; And, α = α0 = α1; Wherein, α0 is the top half angle of the clamping block (61), α1 is the top half angle of the first limiting end (2) and the second limiting end (4), and 18°<α0<36°.

2. The cylindrical specimen fatigue test loading device according to claim 1, characterized in that: The clamping surfaces of the two clamping blocks (61) are both provided with limiting grooves (8) along the length direction.

3. The cylindrical specimen fatigue test loading device according to claim 1, characterized in that: The outer wall of the force applying member (3) is provided with an external thread (31); The load transfer member (1) comprises a first pipe member (11) and a second pipe member (12) integrally formed with the first pipe member (11); the inner diameter of the first pipe member (11) is larger than the inner diameter of the second pipe member (12); the inner wall of the first pipe member (11) is provided with a first internal thread (13) matching with the load transfer end of the fatigue testing machine; the first limiting end (2) is provided at one end of the inner wall of the second pipe member (12) close to the first pipe member (11); and the inner wall of the second pipe member (12) is provided with a second internal thread (14) matching with the external thread (31) of the force-applying member (3) at one end away from the first pipe member (11).

4. The cylindrical specimen fatigue test loading device according to claim 3, characterized in that: A first hexagonal anchoring end (9) is provided at the connecting end surface of the first pipe fitting (11) and the second pipe fitting (12); a second hexagonal anchoring end (10) formed integrally with the force applying member (3) is provided at the end of the force applying member (3) which is located at the inward contraction of the second limiting end (4); the second limiting end (4) extends into the second hexagonal anchoring end (10); and the through hole (5) is provided in the middle of the second hexagonal anchoring end (10).

5. The cylindrical specimen fatigue test loading device according to claim 4, characterized in that: It also includes a rubber gasket (15) and an anti-disturbance nut (16) that match the force-applying member (3); the inner wall of the anti-disturbance nut (16) is provided with a third internal thread (161) that matches the external thread (31) of the force-applying member (3); and the surface of the anti-disturbance nut (16) is rolled with a mesh knurling pattern.

6. The cylindrical specimen fatigue test loading device according to claim 1, characterized in that: The volume of the cavities inside the first limiting end (2) and the second limiting end (4) is less than half the volume of the spindle-shaped structure formed by the two clamping blocks (61) clamping the columnar sample (7); The length l0 of the clamping block (61) satisfies Wherein, l1 is the length of the first limiting end (2) and the second limiting end (4), and the units of l1 and l0 are both mm.

7. The columnar specimen fatigue test loading device according to claim 5, characterized in that: The inner wall of the first limiting end (2) and the outer surface of the clamping block (61) are ground and polished surfaces, and both side surfaces of the rubber gasket (15) are provided with linear raised patterns.

Images