Clamp for three-point bending test and test equipment comprising same

Abstract

The utility model relates to the technical field of alternating stress creep tests, in particular to a clamp for a three-point bending test and test equipment comprising the same, and the clamp comprises a base and two support plates which are oppositely arranged; each supporting plate is further connected with a sliding seat, and the bottom and the side wall of each supporting plate are connected with the sliding seats at the same time. The sliding seat is further connected with the base through a connecting piece, and the distance between the two supporting plates can be adjusted. The test equipment comprises a pressurizing device and the clamp, wherein the pressurizing device is used for applying pressure to the middle position of the sample. Through the clamp and the test equipment comprising the clamp, the problems of unstable connection and complex spacing adjustment can be effectively solved.

Description

Technical Field

[0001] The utility model relates to the technical field of alternating stress creep test, in particular to a fixture used for a three-point bending test and a test device containing the fixture. Background Art

[0002] Creep mainly refers to the phenomenon that the strain of a solid material increases over time while the stress remains unchanged. Many engineering problems involve creep. As an important component of a pumped storage unit, the rotor wire rod is related to a series of safety issues, so the detection of the mechanical and electrical performance indicators of the wire rod is also particularly important. The three-point bending creep test is one of the basic methods for testing the mechanical properties of materials. It usually places the sample in a test device for a three-point bending test, that is, a sample fixture for testing. However, since the effective test span and effective test width of the current three-point bending test device are relatively small, and the fracture space of the sample is also limited, it only stays at the measurement stage of the sample. Therefore, in order to simulate the centrifugal force on the rotor wire rod of a variable speed pumped storage unit during operation, a technician in this field provides a three-point bending test device, which uses an experimental method of applying weights to simulate the three-point bending force of the wire rod to solve the above-mentioned problems.

[0003] In the prior art, a Chinese utility model patent document with publication number CN216669516U and authorization announcement date of June 3, 2022 is proposed. The technical solution disclosed in the patent document is as follows: a new three-point bending fixture, comprising two symmetrically arranged fixtures and an extrusion block, and also symmetrically arranged support columns, the upper ends of the two support columns are connected with a top plate, the lower ends of the two support columns are connected with support feet, the inner sides of the two support columns are connected with a detachable placement table, the upper side wall of the placement table is connected with a slide groove 1 connected to the two sides of the placement table, screws are rotatably provided at both ends of the two slide grooves, and a rotating seat rotatably sleeved on the outside of the screw is connected in the slide groove 1. A driving mechanism for screw rotation is provided on the placement table, and a slider 1 is connected at the lower ends of the two fixtures, and the two sliders 1 are threadedly sleeved on the two ends of the screw, and the slider 1 is against the inner wall of the slide groove 1.

[0004] During actual use of the above technical solution, the following problems may arise: the spacing between the two symmetrically arranged clamps is adjusted by the cooperation of the screw and the slider, and the adjustment method is complicated; and the clamp is set on the screw through the slider, and when the sample is placed on the clamp, the connection is easily unstable. Summary of the invention

[0005] In order to solve the above technical problems, the utility model proposes a fixture for a three-point bending test and a test device containing the same, which can effectively solve the problems of unstable connection and complex spacing adjustment.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] A fixture for a three-point bending test comprises a base and two oppositely arranged support plates; each support plate is also connected to a slide seat, and the bottom and side walls of the support plate are simultaneously connected to the slide seat; the slide seat is also connected to the base through a connecting piece, and can realize the adjustment of the distance between the two support plates.

[0008] The support plate is in a trapezoidal shape that is wider at the top and narrower at the bottom.

[0009] A limiting piece is provided on the top of the support plate, and the minimum spacing between the two limiting pieces is greater than the minimum spacing between the two support plates; the limiting piece and the top of the support plate enclose a placement space for placing the sample.

[0010] The support plate is provided with a lifting hole.

[0011] The base is provided with an inverted T-shaped groove, and the slide seat is provided with a through hole; the connecting piece includes a threaded column and a nut.

[0012] A test device for a three-point bending test comprises the above-mentioned fixture and a pressurizing device, wherein the pressurizing device is used to apply pressure to the middle position of the sample.

[0013] The pressure device comprises a supporting roller and weights suspended at both ends of the supporting roller, and the supporting roller is placed in the middle of the sample.

[0014] The pressurizing device includes a connecting plate, a column, a linear bearing matched with the column, and a support column detachably connected to the lower surface of the connecting plate; the upper surface of the connecting plate is used for placing weights; a pressure head is also provided on the lower surface of the connecting plate, and a pressure roller is also provided at the end of the pressure head; the linear bearing is arranged in the connecting plate and sleeved on the column, and is used for the connecting plate to drive the pressure roller to apply pressure to the sample under the gravity of the weight.

[0015] The column is also provided with a limit screw.

[0016] It also includes a weight tray for placing weights, and the weight tray is arranged on the upper surface of the connecting plate.

[0017] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0018] 1. In the present invention, the support plate is connected to the base through a slide seat, so that the distance between the two support plates can be adjusted, and the adjustment method is simple and stable. The bottom and side wall of the support plate are connected to the slide seat at the same time, and the connection is more stable.

[0019] 2. The support plate is in a trapezoidal shape that is wide at the top and narrow at the bottom, which can increase the number of samples while reducing the floor space.

[0020] 3. The setting of the limiting member makes the sample placement more stable and can also play a good limiting role on the sample, thereby facilitating the improvement of the test accuracy.

[0021] 4. The support plate is provided with a lifting hole, which can lift the support plate to facilitate better storage and adjustment of the spacing between the support plates.

[0022] 5. In this test equipment, the pressure device can apply pressure to the middle position of the sample, which makes the test accuracy higher.

[0023] 6. When the required added stress is small, the pressure device includes a support roller and weights suspended at both ends of the support roller. Stress aging is completed by hanging the weights, and the test method is simple.

[0024] 7. When the required added stress is large, the pressure device may include a connecting plate, a column, a linear bearing and a support column. Under the gravity of the weight, the connecting plate drives the pressure roller to apply pressure to the sample.

[0025] 8. The limit screw can prevent the connecting plate and the fixture from colliding.

[0026] 9. The setting of the weight tray can increase the upper limit of the weight as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementations, wherein:

[0028] Figure 1 It is a structural schematic diagram of the clamp in the utility model;

[0029] Figure 2 It is the front view of the test equipment in the utility model;

[0030] Figure 3 It is a left view of the test equipment in the utility model;

[0031] Markings in the figure:

[0032] 1. Base, 2. Support plate, 3. Slide, 4. Lifting hole, 5. Groove, 6. Connector, 7. Support roller, 8. Weight, 9. Connecting plate, 10. Column, 11. Linear bearing, 12. Support column, 13. Pressure head, 14. Pressure roller, 15. Limit screw, 16. Weight tray, 17. Handle, 18. Sample. DETAILED DESCRIPTION

[0033] Example 1

[0034] As a basic implementation mode of the utility model, the utility model includes a fixture for a three-point bending test, including a base 1 and two support plates 2 arranged opposite to each other. Each support plate 2 is also connected to a slide 3, and the bottom and side walls of the support plate 2 are simultaneously connected to the slide 3. This embodiment does not limit the connection method between the support plate 2 and the slide 3, which can be a fixed connection method such as welding, or a pin connection or a bolt connection. The slide 3 is also connected to the base 1 through a connecting member 6, and can adjust the distance between the two support plates 2. Among them, this embodiment does not limit the specific structure of the connecting member 6, and the slide 3 and the base 1 can be threaded, pinned or snap-fitted.

[0035] Example 2

[0036] As a preferred embodiment of the present invention, the present invention includes a fixture for three-point bending test, referring to the attached manual Figure 1 , comprising a base 1 and two oppositely arranged support plates 2. Each support plate 2 is also connected to a slide seat 3, and the bottom and side wall of the support plate 2 are connected to the slide seat 3 at the same time.

[0037] The slide 3 is also connected to the base 1 through a connector 6, and can adjust the spacing between the two support plates 2. Specifically, the base 1 is provided with an inverted T-shaped groove 5, and the slide 3 is provided with a through hole. The connector 6 includes a threaded column and a nut. The bottom end of the threaded column is connected to the groove 5 of the base 1, and the top of the threaded column is sleeved with a nut. When the nut is unscrewed, the left and right support plates 2 and the slide 3 can slide in the inverted T-shaped groove 5; when the nut is tightened, the left and right support plates 2 and the slide 3 can be fixed on the base 1.

[0038] Furthermore, in order to reduce the occupied area without reducing the number of samples 18, the support plate 2 may be in a trapezoidal shape that is wider at the top and narrower at the bottom.

[0039] In order to facilitate the movement of the clamp, a handle 17 is also provided on the base 1 .

[0040] Based on the above-mentioned fixture, this embodiment also includes a test device for a three-point bending test, and the test device includes the above-mentioned fixture and a pressure device. The pressure device includes a support roller 7 and weights 8 suspended at both ends of the support roller 7. In this embodiment, the number of samples 18 is five. During the test, the two ends of the sample 18 are placed on two support plates 2 respectively. The support roller 7 is placed in the middle position of the sample 18, and is used to apply pressure to the middle position of the sample 18, and the stress magnitude in the long-term process is changed by cyclically adjusting the weight 8.

[0041] Example 3

[0042] As another preferred embodiment of the utility model, the utility model includes a fixture for a three-point bending test, including a base 1 and two oppositely arranged support plates 2. Each support plate 2 is also connected to a slide seat 3, and the bottom and side walls of the support plate 2 are simultaneously connected to the slide seat 3. The slide seat 3 is also connected to the base 1 through a connecting member 6, and the spacing between the two support plates 2 can be adjusted.

[0043] A stopper is provided on the top of the support plate 2, and the stopper may be in the shape of a plate, and the minimum spacing between the two stoppers is greater than the minimum spacing between the two support plates 2. The minimum spacing between the two stoppers specifically refers to the distance between the side surfaces on the opposite side of the two stoppers. The minimum spacing between the support plates 2 specifically refers to the distance between the side surfaces on the opposite side of the two support plates 2. The stopper and the top of the support plate 2 enclose a placement space for placing the sample 18.

[0044] Example 4

[0045] As another preferred embodiment of the utility model, the utility model includes a fixture for a three-point bending test, including a base 1 and two oppositely arranged support plates 2. Each support plate 2 is also connected to a slide seat 3, and the bottom and side walls of the support plate 2 are simultaneously connected to the slide seat 3. The slide seat 3 is also connected to the base 1 through a connecting member 6, and the spacing between the two support plates 2 can be adjusted.

[0046] The utility model also includes a test device for a three-point bending test, including the above-mentioned clamp and a pressure device. The pressure device is used to apply pressure to the middle position of the sample 18. Specifically, the pressure device includes a connecting plate 9, a column 10, a linear bearing 11 matched with the column 10, and a support column 12 detachably connected to the lower surface of the connecting plate 9. The upper surface of the connecting plate 9 is used to place the weight 8. A pressure head 13 is also provided on the lower surface of the connecting plate 9, and a pressure roller 14 is also provided at the end of the pressure head 13. The linear bearing 11 is arranged in the connecting plate 9 and is sleeved on the column 10, and is used for the connecting plate 9 to drive the pressure roller 14 to apply pressure to the sample 18 under the gravity of the weight 8.

[0047] Example 5

[0048] As the best embodiment of the present utility model, refer to the attached specification Figure 2 And the instruction manual Figure 3 The utility model includes a fixture for three-point bending test, including a base 1, a slide 3, a handle 17 and two oppositely arranged support plates 2. The handle 17 is connected to the base 1 and is used to move the fixture. The base 1 and the support plate 2 are both made of steel structures, and an inverted T-shaped groove 5 is horizontally provided at the top center of the base 1.

[0049] Each support plate 2 is connected to a slide seat 3. Specifically, the support plate 2 and the slide seat 3 are an integrated structure, the slide seat 3 is in an inverted T shape, and the bottom and side walls of the support plate 2 are connected to the slide seat 3 at the same time. The slide seat 3 is also connected to the base 1 through a connector 6, and the spacing between the two support plates 2 can be adjusted. Specifically, the connector 6 includes a threaded column and a nut. A through hole is provided in the middle of the slide seat 3, through which a threaded column is passed. The bottom end of the threaded column is connected to the groove 5 of the base 1, and a nut is sleeved on the top of the threaded column. When the nut is unscrewed, the two oppositely arranged support plates 2 and the slide seat 3 on the left and right can slide in the groove 5; when the nut is tightened, the two oppositely arranged support plates 2 and the slide seat 3 on the left and right can be fixed on the base 1. Therefore, the span can be changed by fixing the nut on the top of the threaded column, that is, the spacing between the two support plates 2 can be adjusted.

[0050] In this embodiment, the base 1 may be 500 mm long and 410 mm wide. The left and right support plates 2 may be located at any position within the range of the groove 5, and the position is not fixed, so the applicability is wider, and the adjustable span range is 50-300 mm.

[0051] Furthermore, the support plate 2 presents a trapezoidal shape that is wide at the top and narrow at the bottom. A limiter is provided on the top of the support plate 2, and the limiter can be a round roller. The minimum spacing between the two limiters is greater than the minimum spacing between the two support plates 2. Among them, the minimum spacing between the two limiters specifically refers to: the distance between the surfaces of the opposite sides of the two round rollers, and the minimum spacing between the two support plates 2 specifically refers to: the distance between the sides of the opposite sides of the two support plates 2. The limiter and the top of the support plate 2 enclose a placement space, and 1-5 samples 18 can be randomly added as needed.

[0052] Furthermore, a rectangular lifting hole 4 is opened in the middle of each of the support plates 2 .

[0053] Furthermore, the present embodiment also includes a test device for a three-point bending test, including the above-mentioned fixture and a pressurizing device. The pressurizing device can be freely selected according to the size of the stress to be applied.

[0054] When the stress to be added is small, the pressurizing device may include a support roller 7 and weights 8 suspended at both ends of the support roller 7, and stress aging is completed by placing the support roller 7 in the middle of the sample 18 and suspending the weights 8 at both ends of the support roller 7. When the stress to be added is large, the pressurizing device may include a connecting plate 9, four columns 10, a linear bearing 11, two support columns 12 and a weight tray 16.

[0055] Specifically, the support column 12 is detachably connected to both sides of the lower surface of the connecting plate 9. A pressure head 13 is also installed at the center of the lower surface of the connecting plate 9, and a pressure roller 14 is also provided at the end of the pressure head 13 to fit with the pressure head 13. The pressure roller 14 is cylindrical in shape, with a diameter of 20 mm and a length of 40 cm. It is located in the middle of the left and right support plates 2 and serves as a medium for applying stress. The height from the outer circle of the pressure roller 14 to the weight tray 16 is 60 mm.

[0056] The weight tray 16 is arranged on the upper surface of the connecting plate 9 and is used to place the weights 8. After the test equipment is installed, according to the breaking load of the sample 18, a suitable number of weights 8 are added. The weights 8 are cylinders with a diameter of 380 mm and a single weight of 20 kg. In this embodiment, the limit of the number of weights 8 added is 49 pieces. When all the weights 8 are placed on the weight tray 16, the total height of the device is about 1530 mm.

[0057] A linear bearing 11 matching the column 10 is disposed in the connecting plate 9 , and the linear bearing 11 is sleeved on the column 10 , so that the connecting plate 9 drives the pressure roller 14 to apply pressure to the sample 18 under the gravity of the weight 8 .

[0058] Furthermore, the column 10 is provided with a limit screw 15 to prevent the connection plate 9 from colliding with the clamp.

[0059] The test is carried out using the above test equipment, including the following steps:

[0060] (1) According to the actual conditions, the rotor wire rods of the variable speed pumped storage unit were selected as experimental materials and cut into test lengths that meet national standards.

[0061] (2) Install the fixture on the base plate, ensure that the fixture is parallel and stable to the pressure device, and use the cooperation of the four columns 10 and the linear bearing 11 to achieve guidance, ensure that the pressure head 13 is vertically downward, and is responsible for providing static force loading in the vertical direction.

[0062] (3) Since the support columns 12 on both sides support the pressure head 13, a certain space is left between the pressure head 13 and the support plate 2, which is convenient for installing the sample 18. When in use, the spacing between the support plates 2 is changed by screwing the nut on the top of the threaded column of the support plate 2 and moving the slide 3. The appropriate span is selected according to the length of the rotor bar. After moving to the required position for the test, the nut is tightened to fix the two support plates 2 connected to the slide 3 on the support base 1, and then the rotor bar is placed on the top of the two support plates 2. After the sample 18 is installed, the support columns 12 on both sides are taken out.

[0063] (4) At this time, a suitable number of weights 8 can be placed in the weight tray 16 above the pressure head 13, and the connecting plate 9 can be moved up and down to make the pressure roller 14 contact with the sample 18, so as to apply stress to the middle position of the sample 18, thereby performing a three-point bending creep test on the rotor bar.

[0064] To sum up, after reading the utility model document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical scheme and technical concept of the utility model without creative mental labor, which all fall within the scope of protection of the utility model.

Claims

1. A fixture for a three-point bending test, characterized in that: The invention comprises a base (1) and two support plates (2) arranged opposite to each other; each support plate (2) is also connected to a slide seat (3), and the bottom and side wall of the support plate (2) are simultaneously connected to the slide seat (3); the slide seat (3) is also connected to the base (1) via a connecting piece (6), and can realize the adjustment of the distance between the two support plates (2).

2. A fixture for three-point bending test according to claim 1, characterized in that: The support plate (2) is in a trapezoidal shape that is wider at the top and narrower at the bottom.

3. A fixture for three-point bending test according to claim 2, characterized in that: A limiting member is provided on the top of the support plate (2), and the minimum spacing between the two limiting members is greater than the minimum spacing between the two support plates (2); the limiting member and the top of the support plate (2) together form a placement space for placing the sample (18).

4. A fixture for three-point bending test according to claim 2, characterized in that: The support plate (2) is provided with a lifting hole (4).

5. A fixture for three-point bending test according to claim 1, characterized in that: The base (1) is provided with an inverted T-shaped groove (5), and the slide seat (3) is provided with a through hole; the connecting member (6) comprises a threaded column and a nut.

6. A test apparatus for a three-point bending test, characterized in that: The clamp comprises the fixture as claimed in any one of claims 1 to 5, and further comprises a pressure-applying device, wherein the pressure-applying device is used to apply pressure to the middle position of the sample (18).

7. A test device for a three-point bending test according to claim 6, characterized in that: The pressure device comprises a support roller (7) and weights (8) suspended at both ends of the support roller (7), and the support roller (7) is placed in the middle of the sample (18).

8. The test equipment for three-point bending test according to claim 6, characterized in that: The pressurizing device comprises a connecting plate (9), a column (10), a linear bearing (11) matched with the column (10), and a support column (12) detachably connected to the lower surface of the connecting plate (9); the upper surface of the connecting plate (9) is used for placing a weight (8); the lower surface of the connecting plate (9) is also provided with a pressure head (13), and the end of the pressure head (13) is also provided with a pressure roller (14); the linear bearing (11) is arranged in the connecting plate (9) and sleeved on the column (10), and is used for the connecting plate (9) to drive the pressure roller (14) to apply pressure to the sample (18) under the gravity of the weight (8).

9. A test device for a three-point bending test according to claim 8, characterized in that: The upright column (10) is also provided with a limit screw (15).

10. A test device for a three-point bending test according to claim 9, characterized in that: It also includes a weight tray (16) for placing the weight (8), and the weight tray (16) is arranged on the upper surface of the connecting plate (9).

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