A sling bending fatigue test device

Abstract

The present invention belongs to the technical field of material experiment, and discloses a sling tension-bending fatigue experiment device. The device includes a reaction frame, an axial force loading module, an anchoring module, a bending loading module, a clamping module and a protection module. Among them, the axial force loading module, the anchoring module and the protection module are arranged on the columns of the reaction frame, the bending loading module is arranged on the cross beam of the reaction frame, and the clamping module is anchored to the ground. The axial force loading module is used to apply axial load, the anchoring module is used to fix the specimen, the bending loading module is used to apply bending load for tension-bending, both the clamping module and the bending loading module can control the bending load received by the specimen, and the protection module is used to prevent injuries caused by specimen fracture; The present invention provides a fatigue experiment device capable of simultaneously performing axial tension and bending, and obtaining various fatigue performance indexes of steel strands or parallel steel wires through tension-bending fatigue experiments, which is applicable to sling tension-bending fatigue experiments.

Description

Technical Field

[0001] The present invention relates to the technical field of material experiment, and particularly relates to a sling tension-bending fatigue experiment device. Background Art

[0002] Tension-bending fatigue refers to the fatigue phenomenon that occurs when a sling is subjected to cyclic tensile and bending loads. In an actual bridge, short slings are prone to this fatigue problem due to their own structural characteristics and the external environment they are in. Since short slings have a relatively short length and a relatively large stiffness, they are subjected to greater live loads and live load impact forces. At the same time, under the action of temperature changes, when the bridge deck undergoes horizontal displacement, the ends of the short slings will be subjected to reciprocating bending stresses, resulting in a tension-bending combined stress cycle in the cross-section stress of the steel wires, and thus causing steel wire fatigue.

[0003] Tension-bending fatigue is one of the main forms of sling failure. As an important force-transferring component in a bridge structure, a sling is often subjected to repeated tensile and bending loads for a long time and is in various adverse external environments. Therefore, the main cause of sling failure is often fatigue. A sling is generally composed of steel strands or parallel steel wires. Therefore, in order to more accurately evaluate the safety of a sling, it is necessary to study the fatigue performance of steel strands or parallel steel wires under the coupling of various actions. To accurately detect the tension-bending fatigue performance of steel strands or parallel steel wires, a fatigue experiment device capable of simultaneously performing axial tension and bending needs to be established, and various fatigue performance indexes of steel strands or parallel steel wires can be obtained through tension-bending fatigue experiments. Summary of the Invention

[0004] The present invention aims to provide a sling tension-bending fatigue experiment device to accurately detect the tension-bending fatigue performance of steel strands or parallel steel wires.

[0005] To achieve the above object, the present invention provides the following technical solution:

[0006] A sling tension-bending fatigue experiment device includes a reaction frame, an axial force loading module, an anchoring module, a bending loading module, a clamping module, and a protection module. The reaction frame includes a first cross beam and columns. The axial force loading module, the anchoring module, and the protection module are all arranged on the columns. The bending loading module is arranged on the first cross beam. The clamping module is anchored to the ground;

[0007] The axial force loading module includes a jack, a top plate, four first precision rolled threaded steels, and a smooth round steel bar. The jack abuts between two top plates. The two top plates are fixed by four first precision rolled threaded steels. The top plate is connected to the anchoring module through four first precision rolled threaded steels. The smooth round steel bar penetrates through the column, and the lower two first precision rolled threaded steels are placed on the top of the smooth round steel bar;

[0008] The anchoring module is used to fix the specimen. The anchoring module includes a welded I-beam, a welded U-shaped plate, a load sensor, and an anchor. The welded I-beam is connected to the axial force loading module through four first rolled threaded steel bars. The welded U-shaped plate is connected to the column on the side opposite to the axial force loading module. The welded I-beam is used to fix one end of the specimen, and the welded U-shaped plate is used to fix the other end of the specimen. The specimen passes through the load sensor and the anchor. The load sensor is arranged between the anchor and the welded I-beam, and the load sensor is used to monitor the applied pressure;

[0009] The bending loading module includes an MTS testing machine and a central fixture. The MTS testing machine is arranged on the first cross beam, and the central fixture is connected to the loading platform of the MTS testing machine. The central fixture is used to fix the specimen and transfer the force loaded by the MTS testing machine to the specimen;

[0010] The clamping module includes a sliding fixture, an I-beam, and a second cross beam. The sliding fixture is slidably connected to the I-beam through a card slot. The second cross beam is anchored to the ground through second rolled threaded steel bars. The bottom of the second cross beam abuts against the top of the I-beam;

[0011] The protection module includes a protection plate and a lead screw. The protection plates are arranged on both sides of the specimen. The protection plates pass through the welded I-beam and the U-shaped plate and are connected to the columns on both sides by bolts. The lead screw passes through the protection plates and is arranged on the upper and lower sides of the specimen.

[0012] Furthermore, pads are arranged at both ends of the load sensor, and the pads are used to prevent the load sensor from being damaged due to stress concentration.

[0013] Furthermore, two plain round steel bars are provided, and the two plain round steel bars are symmetrically arranged along the vertical center line of the column.

[0014] Furthermore, the central fixture is connected to the loading platform of the MTS testing machine by bolts.

[0015] Furthermore, four protection plates are provided, and the protection plates on the same side are connected by bolts.

[0016] Principle of the technical solution: In this device, the jack serves as the loading device. The jack transmits the force to the top plates at both ends of the jack. The top plates transfer the force to the anchoring module through the first high-strength precision rolled thread steel, thereby achieving the purpose of tensioning the test piece. The two first high-strength precision rolled thread steels at the lower side are placed on top of the plain round steel, enabling the threads of the first high-strength precision rolled thread steel to move through the rotation of the plain round steel to achieve the purpose of force transmission. After the experiment, the first high-strength precision rolled thread steel can also be anchored by nuts, and then the jack is unloaded. The MTS testing machine is used to perform bending loading on the test piece, and the central fixture is used to fix the test piece and transfer the force loaded by the MTS testing machine to the test piece. The slidable fixture can slide on the I-beam, so that it can be adjusted according to the required bending length of the test piece to be tested. The position of the I-beam is fixed by the second cross beam and the second high-strength precision rolled thread steel. Both ends of the test piece are connected and fixed by the welded I-shaped plate and the welded U-shaped plate respectively. The load sensor is used to monitor the applied tensile force, and the backing plate is used to protect the load sensor. The protective plate can prevent damage caused by the fracture of the test piece during the loading process, and the lead screw can limit the position of the steel wire when the test piece fractures.

[0017] Advantages of the technical solution: This device can realize the fatigue experiment of steel strands and parallel steel wires under the combined action of tension and bending. This device is conducive to simulating the tension-bending fatigue environment of the steel strands and parallel steel wires to be tested and obtaining more real and approximate tension-bending fatigue experiment parameters. Each module of this device can be disassembled from the reaction frame, which is convenient for the maintenance and repair of the module. The slidable fixture is arranged at the bottom of this device, and the required bending length of the test piece to be tested can be controlled by changing the distance between the slidable fixtures. Description of the Drawings

[0018] Figure 1 It is the structure diagram of the present invention;

[0019] Figure 2 It is the structure diagram of the present invention without the protective module;

[0020] Figure 3 It is the enlarged view of the anchoring module of the present invention;

[0021] The names of the corresponding reference signs in the drawings are: reaction frame 1, axial force loading module 2, anchoring module 3, bending loading module 4, clamping module 5, protective module 6, test piece 7, first cross beam 11, column 12, jack 21, top plate 22, first high-strength precision rolled thread steel 23, plain round steel 24, I-shaped plate 31, welded U-shaped plate 32, load sensor 33, anchor 34, backing plate 35, MTS testing machine 41, central fixture 42, slidable fixture 51, I-beam 52, second cross beam 53, second high-strength precision rolled thread steel 54, protective plate 61, lead screw 62. Detailed Implementation Manner

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments:

[0023] As Figures 1 - 3 shown, a sling bending fatigue test device includes a reaction frame 1, an axial force loading module 2, an anchoring module 3, a bending loading module 4, a clamping module 5 and a protection module 6. The reaction frame 1 includes a first cross beam 11 and two columns 12. The axial force loading module 2, the anchoring module 3 and the protection module 6 are all located on the columns 12 of the reaction frame 1. The bending loading module 4 is arranged on the first cross beam 11 of the reaction frame 1, and the clamping module 5 is anchored to the ground.

[0024] The axial force loading module 2 includes a jack 21, a top plate 22, a first high-strength threaded steel 23 and a plain round bar 24. The jack 21 serves as a loading device. The jack 21 is arranged between two top plates 22. The two ends of the jack 21 are in contact with the top plates 22. The two top plates 22 are fixedly connected by four first high-strength threaded steels 23. The four first high-strength threaded steels 23 also fixedly connect the top plates 22 to the welded I-beam 31 in the anchoring module 3. The two first high-strength threaded steels 23 at the lower edge are placed on two plain round bars 24 passing through the column 12. The two plain round bars 24 are symmetrically arranged along the vertical center line of the column 12.

[0025] The anchoring module 3 includes a welded I-beam 31, a welded U-shaped plate 32, a load sensor 33, an anchor 34 and a backing plate 35. The welded I-beam 31 is connected to the top plate 22 in the axial force loading module 2 by four first threaded steels. The load sensor 33 is arranged at the left end of the welded I-beam 31 for monitoring the applied pressure. A backing plate 35 is arranged between the welded I-beam 31 and the load sensor 33. An anchor 34 is arranged at the left end of the load sensor 33. A backing plate 35 is also arranged between the anchor 34 and the load sensor 33. The welded U-shaped plate 32 is connected to the right column 12 by bolts. The welded I-beam 31 is used to fix the left end of the specimen 7, and the welded U-shaped plate 32 is used to anchor the right end of the specimen 7.

[0026] The bending loading module 4 includes an MTS testing machine 41 and a central fixture 42. Steel plates are provided on the upper and lower sides of the first cross beam 11. The upper and lower steel plates are restricted and fixed by threaded steels. The lower steel plate is connected to the MTS testing machine 41. The MTS testing machine 41 is used to perform bending loading on the specimen 7. The central fixture 42 is connected to the loading platform on the lower side of the MTS testing machine 41 by bolts. The central fixture 42 is used to fix the specimen 7 and transmit the force loaded by the MTS testing machine 41 to the specimen 7.

[0027] The clamping module 5 includes a slidable fixture 51, an I-beam 52, and a second cross beam 53. The slidable fixture 51 is connected to the I-beam 52 through a card slot, and the slidable fixture 51 can slide along the I-beam 52. The second cross beam 53 is placed on the top of the I-beam 52, and the second cross beam 53 is anchored to the ground through a second high-strength rolled thread steel 54.

[0028] The protection module 6 includes a protection plate 61 and a lead screw 62. Among them, the protection plate 61 is provided with four pieces. The four protection plates 61 respectively pass through the welded I-shaped plate 31 and the welded U-shaped plate 32 and are fixed to the columns 12 at both ends through bolts. The protection plates 61 on the same side are fixed through bolts. The protection plate 61 can prevent the damage caused by the fracture of the test piece 7. The lead screw 62 passes through the upper and lower sides of the protection plate 61. The test piece 7 is located between the upper and lower lead screws 62. The upper and lower lead screws 62 are used to limit the position of the test piece 7 during fracture.

[0029] The specific implementation process is as follows:

[0030] First, place the I-beam 52 on the ground, insert the slidable fixture 51 into the I-beam 52 from the flanges at the left and right ends of the I-beam 52. At the same time, symmetrically place the two second cross beams 53 on the top of the I-beam 52. The slidable fixture 51 is located between the two second cross beams 53. Then, anchor the second cross beam 53 to the ground through the second high-strength rolled thread steel 54, thereby restricting and fixing the I-beam 52. Then, clamp the test piece 7 on the central fixture 42 and the slidable fixture 51. The left end of the test piece 7 is anchored to the welded I-shaped plate 31 and sequentially passes through the backing plate 35, the load sensor 33, the backing plate 35, and the anchor 34. The right end of the test piece 7 is anchored to the welded U-shaped plate 32. After the installation of the test piece 7 is completed, apply a longitudinal load through the jack 21 to drive the top plate 22 and the first high-strength rolled thread steel 23, so that the test piece 7 to be tested is in a tension state. After the data of the load sensor 33 is stable, use a nut to fix the position of the top plate 22, and then unload the jack 21. During the test, the MTS testing machine 41 applies a bending load to the test piece 7 through displacement control and conducts cyclic loading. During the whole experiment, the bending load received by the test piece 7 can be controlled by adjusting the vertical displacement of the MTS testing machine 41 and the horizontal displacement of the slidable fixture 51, which is beneficial to simulating the tension-bending fatigue environment of the test piece 7 to be tested and obtaining more real and approximate tension-bending fatigue test parameters.

[0031] The above are only embodiments of the present invention, and common general technical solutions or characteristics in the solutions are not described in detail herein. It should be noted that for those skilled in the art, without departing from the technical solutions of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application shall be subject to the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. A sling bending fatigue test device, characterized in that : comprising a reaction frame (1), an axial force loading module (2), an anchoring module (3), a bending loading module (4), a clamping module (5) and a protection module (6), wherein the reaction frame (1) comprises a first crossbeam (11) and a column (12), the axial force loading module (2), the anchoring module (3) and the protection module (6) are all arranged on the column (12), the bending loading module (4) is arranged on the first crossbeam (11), and the clamping module (5) is anchored on the ground; The axial force loading module (2) comprises a jack (21), a top plate (22), a first fine-rolled threaded steel bar (23) and a plain round steel bar (24); the jack (21) is abutted between two top plates (22); the two top plates (22) are fixed by four of the first fine-rolled threaded steel bars (23); the top plate (22) is connected to the anchoring module (3) by the four of the first fine-rolled threaded steel bars (23); the plain round steel bar (24) passes through the column (12); and the two first fine-rolled threaded steel bars (23) on the lower side are placed on the top of the plain round steel bar (24); The anchoring module (3) is used to fix the test piece (7). The anchoring module (3) comprises a welded I-shaped plate (31), a welded U-shaped plate (32), a load sensor (33) and an anchor (34). The welded I-shaped plate (31) is connected to the axial force loading module (2) via four of the first fine-rolled threaded steel bars (23). The welded U-shaped plate (32) is connected to a column (12) on the opposite side of the axial force loading module (2). The welded I-shaped plate (31) is used to fix one end of the test piece (7). The welded U-shaped plate (32) is used to fix the other end of the test piece (7). The test piece (7) is penetrated by the load sensor (33) and the anchor (34). The load sensor (33) is arranged between the anchor (34) and the welded I-shaped plate (31). The load sensor (33) is used to monitor the applied pressure. The bending loading module (4) comprises an MTS testing machine (41) and a central fixture (42), wherein the MTS testing machine (41) is arranged on the first crossbeam (11), and the central fixture (42) is connected to the force application platform of the MTS testing machine (41), and the central fixture (42) is used to fix the test piece (7) and transmit the force applied by the MTS testing machine (41) to the test piece (7); The clamping module (5) comprises a slidable clamp (51), an I-beam (52) and a second crossbeam (53); the slidable clamp (51) is slidably connected to the I-beam (52) via a slot; the second crossbeam (53) is anchored to the ground via a second precision-rolled threaded steel bar (54); the bottom of the second crossbeam (53) is in abutment contact with the top of the I-beam (52); The protection module (6) comprises a protection plate (61) and a lead screw (62); the protection plate (61) is arranged on both sides of the test piece (7); the protection plate (61) passes through the welded I-shaped plate (31) and the welded U-shaped plate (32) and is connected to the columns (12) on both sides by bolts; the lead screw (62) passes through the protection plate (61) and is arranged on the upper and lower sides of the test piece (7).

2. A sling bending fatigue test device according to claim 1, characterized in that Pads (35) are provided at both ends of the load sensor (33), and the pads (35) are used to prevent stress concentration from causing damage to the load sensor (33).

3. The cable bending fatigue test device according to claim 1 is characterized in that The number of the plain round steel bars (24) is two, and the two plain round steel bars (24) are symmetrically arranged along the vertical center line of the column (12).

4. The cable bending fatigue test device according to claim 1 is characterized in that The central fixture (42) is connected to the force-applying platform of the MTS testing machine (41) by bolts.

5. The cable bending fatigue test device according to claim 1 is characterized in that The protective plates (61) are provided in four pieces, and the protective plates (61) on the same side are connected by bolts.

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