Structural fatigue testing machine

Abstract

The application relates to the technical field of material fatigue test, in particular to a structure fatigue testing machine. The structure fatigue testing machine comprises an operation table, the operation table is provided with symmetrically-distributed fixing frames, the fixing frames are slidably connected with symmetrically-distributed guide blocks, the guide blocks are rotatably connected with rotating shafts, the rotating shafts are fixedly connected with connecting plates, the connecting plates symmetrically and close to different fixing frames are fixedly connected with fixing shafts, the fixing shafts are fixedly connected with symmetrically-distributed T-shaped plates, the T-shaped plates are provided with equidistantly-distributed sliding grooves, the symmetrically and close sliding grooves of different fixing frames are jointly slidably connected with connecting pieces, and the connecting pieces are rotatably connected with symmetrically-distributed rollers. The position of the connecting piece on the adjacent sliding groove is adjusted, the bending degree of the two sides of the steel plate is continuously increased in the steel plate bending process, the connecting piece drives the roller to move to support and fix the multiple points of the steel plate, the stress of the two sides of the steel plate is uniform, and the accuracy of the stress change data of the middle part of the steel plate is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material fatigue test, and particularly relates to a structure fatigue testing machine. BACKGROUND

[0002] The structure fatigue testing machine is a key equipment for determining the fatigue strength, fatigue life and crack propagation law of metal materials and structural parts (such as steel plates, beams and connecting parts made of new materials) under repeated loads. The equipment simulates the cyclic stress of the workpiece in the actual working condition to evaluate the durability, and provides important data support for engineering design, material selection and safety evaluation. When fixing the steel plate test piece, the testing machine generally adopts a clamping mode of using four clamping plates (one on the upper side and one on the lower side of each side) on both sides of the steel plate. The clamping plates are driven by hydraulic pressure or fixed by bolts to provide clamping force perpendicular to the plane of the steel plate, so as to firmly fix the two sides of the steel plate to prevent it from slipping or lifting during the test.

[0003] This traditional fixing mode cannot adapt to the dynamic deformation of the steel plate during bending, resulting in uneven distribution of clamping force and affecting the accuracy of test data. Specifically, when the middle part of the steel plate is bent upward under the action of load, the entire steel plate is not only deformed in the middle part. According to the principle of material mechanics, the area extending from the clamping point to the middle part of the steel plate will naturally produce a small amplitude and continuous bending deformation (i.e. curvature change). This means that the two clamping areas of the steel plate do not maintain an ideal rigid and straight state, but will increase with the bending degree of the middle part. The existing clamping plate design usually requires the working surfaces of the upper and lower clamping plates to always remain parallel to provide uniform clamping force. However, this rigid and parallel clamping mode is contradictory to the natural bending deformation of the two sides of the steel plate. As a result, for the side of the steel plate close to the middle part, since the steel plate has already been bent, it tries to separate from the full surface contact with the parallel clamping plate, while the rigid clamping plate forcibly maintains parallel contact, which will cause the clamping plate edge (especially the edge close to the middle part of the steel plate) to produce a concentrated and excessive extrusion stress on the surface of the steel plate, so that the clamping areas on both sides of the steel plate cannot obtain uniform and stable support and constraint. SUMMARY

[0004] In order to overcome the shortcomings of the existing testing machine that cannot provide corresponding support force according to the deformation of the two sides of the steel plate during bending, the purpose of the present application is to provide a self-adjusting structure fatigue testing machine.

[0005] Technical solution: a structure fatigue testing machine, comprising an operating table, the operating table is provided with symmetrically distributed fixing frames, the fixing frames are slidably connected with symmetrically distributed guide blocks, the fixing frames are provided with symmetrically distributed first power modules respectively used for driving adjacent guide blocks to move, the guide blocks are rotatably connected with rotating shafts, the guide blocks are provided with second power modules used for driving adjacent rotating shafts to rotate, the rotating shafts are fixedly connected with connecting plates, the connecting plates symmetrically close to different fixing frames are fixedly connected with a fixed shaft, the fixed shaft is fixedly connected with symmetrically distributed T-shaped plates, the T-shaped plates are provided with equidistantly distributed sliding grooves, the symmetrically close sliding grooves of different fixing frames are jointly and slidably connected with connecting pieces, the connecting pieces are rotatably connected with symmetrically distributed rollers, and the symmetrically distributed rollers are used for clamping steel plates.

[0006] In addition, it is particularly preferred that the connecting plates symmetrically close to different fixing frames are jointly and slidably connected with sliding shafts, the sliding shafts are slidably connected with symmetrically distributed guide plates, the connecting plates are provided with third power modules used for driving the sliding shafts to move, the guide plates are provided with guide grooves, and the connecting pieces slide in the symmetrically distributed guide grooves.

[0007] In addition, it is particularly preferred that the guide grooves are composed of horizontal parts and curved parts, the bending degree of the curved parts of the guide grooves gradually increases from the side close to the horizontal part to the side away from the horizontal part, and the curved parts of the two guide grooves corresponding to the same fixing frame are located between the horizontal parts of the two guide grooves.

[0008] In addition, it is particularly preferred that the longitudinal length of the guide groove is less than the longitudinal length of the sliding groove.

[0009] In addition, it is particularly preferred that the connecting pieces comprise symmetrically distributed sliding pieces, the sliding pieces slide in adjacent sliding grooves and adjacent guide grooves, the sliding pieces are hingedly connected with symmetrically distributed I-shaped rods, the I-shaped rods close to different sliding pieces are jointly hingedly connected with a fixing piece, and the fixing piece is rotatably connected with adjacent rollers.

[0010] In addition, it is particularly preferred that the sliding shaft is fixedly connected with a bidirectional push rod, two telescopic ends of the bidirectional push rod are respectively fixedly connected with adjacent guide plates, the sliding pieces are provided with vertical parts, the guide plates are used for pressing the vertical parts of adjacent sliding pieces, and symmetrically distributed fixing pieces are fixedly connected with symmetrically distributed springs.

[0011] In addition, it is particularly preferred that the rollers are fixedly connected with symmetrically distributed connecting sleeves, and the sliding pieces are fixedly connected with friction blocks used for rubbing adjacent connecting sleeves.

[0012] In addition, it is particularly preferred that the connecting sleeves are made of rubber.

[0013] Furthermore, it is particularly preferred that the symmetrically distributed fixing frames are slidably connected to symmetrically distributed correction plates, the symmetrically distributed correction plates are located on both sides of the symmetrically distributed bidirectional push rods, the symmetrically distributed fixing frames are jointly provided with a fourth power module for driving the symmetrically distributed correction plates to move, and the symmetrically distributed correction plates are jointly used to center the steel plate.

[0014] Furthermore, it is particularly preferred that the correction plate is provided with symmetrically distributed guide portions, and the distance between the symmetrically distributed guide portions on the same correction plate gradually decreases from the side closer to the bidirectional push rod to the side farther away from the bidirectional push rod.

[0015] This invention has the following advantages: By adjusting the position of the connecting piece on the adjacent slide groove, the bending degree of the steel plate on both sides is continuously increased during the bending process, which better matches the actual deformation state of the steel plate during bending. The connecting piece drives the roller to move and support and fix the steel plate at multiple points, so that the force on both sides of the steel plate is uniform, ensuring the accuracy of the stress change data in the middle of the steel plate. The fixing piece drives the roller and connecting sleeve on it to move closer to each other, and the two rollers clamp the steel plate so that the steel plate and the sliding piece are on the same horizontal plane, which facilitates the subsequent synchronous bending adjustment of both sides of the steel plate. The correction plate and its guide part perform the correction operation on the steel plate after placement, thereby ensuring the accuracy of the subsequent steel plate data. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0017] Figure 2 This is a three-dimensional structural diagram of the fixing frame and the correction plate of the present invention;

[0018] Figure 3 This is a three-dimensional structural side view of the present invention;

[0019] Figure 4 This is an exploded view of the three-dimensional structure of the T-shaped plate and the sliding component of the present invention;

[0020] Figure 5 This is a three-dimensional structural diagram of the I-shaped rod and the fixing member of the present invention;

[0021] Figure 6 This is a three-dimensional structural diagram of the steel plate under test conditions according to the present invention.

[0022] In the diagram: 1. Operating table, 111. Steel plate, 2. Fixing frame, 3. Guide block, 4. Rotating shaft, 5. Connecting plate, 6. Fixing shaft, 7. T-shaped plate, 71. Slide groove, 8. Connecting part, 81. Sliding part, 82. I-shaped rod, 83. Fixing part, 84. Spring, 9. Roller, 91. Connecting sleeve, 92. Friction block, 10. Guide plate, 101. Guide groove, 11. Sliding shaft, 12. Two-way push rod, 13. Correction plate. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] Existing testing machines for steel plate fatigue use four clamps to hold the steel plate on both sides when fixing it. When the steel plate bends upwards in the middle, the clamps provide clamping force to both sides. However, under natural bending conditions, the steel plate will bend slightly on both sides, and the degree of bending on both sides will gradually increase as the middle bends. The two clamps need to remain parallel at all times and cannot adapt to the deformation of both sides of the steel plate under bending conditions. This causes the two adjacent clamps to excessively compress the side of the steel plate closer to the middle, making it impossible for the steel plate to receive uniform support force on both sides, thus affecting the acquisition of some data during the bending process of the steel plate.

[0026] A structural fatigue testing machine, such as Figures 1-4 and Figure 6As shown, the system includes an operating platform 1. Two symmetrically distributed fixed frames 2 are mounted on the upper side of the operating platform 1. Two symmetrically distributed guide blocks 3 are slidably connected to the fixed frames 2. Each fixed frame 2 is equipped with a symmetrically distributed first power module for driving the adjacent guide blocks 3. The first power module is a first electric slide rail (not shown in the figure) mounted on the fixed frame 2. The first electric slide rail is slidably connected to a first electric slider fixed to the adjacent guide block 3. Each guide block 3 is rotatably connected to a rotating shaft 4. The guide block 3 is equipped with a second power module for driving the adjacent rotating shaft 4 to rotate. The power module is a motor (not shown in the figure) mounted on guide block 3. The output shaft of the motor is fixedly connected to the adjacent rotating shaft 4. A connecting plate 5 is fixedly connected to the rotating shaft 4. A fixed shaft 6 is fixedly connected to the lower side between two symmetrical connecting plates 5. Two T-shaped plates 7 are symmetrically distributed front and back on the fixed shaft 6. The two T-shaped plates 7 are located between the two connecting plates 5. The T-shaped plates 7 are provided with four equally spaced sliding grooves 71. The symmetrical sliding grooves 71 are slidably connected to a connecting piece 8. There are four connecting pieces 8 on each side. The connecting piece 8 is rotatably connected to two symmetrically distributed rollers 9. Distributed rollers 9 are used to clamp steel plates 111. Two symmetrically arranged connecting plates 5 are slidably connected to a sliding shaft 11 on their upper sides. The sliding shaft 11 is slidably connected to two symmetrically arranged guide plates 10, located between adjacent connecting plates 5 and T-shaped plates 7. The connecting plates 5 are equipped with a third power module for driving the sliding shaft 11. The third power module includes a second electric slide rail mounted on the connecting plates 5. The second electric slide rail is slidably connected to a second electric slider (not shown in the figure) fixed to the sliding shaft 11. The guide plates 10 are provided with guide grooves 101, connecting... The connector 8 slides within the symmetrically distributed guide grooves 101. The guide grooves 101 consist of a horizontal part and a curved part. The curvature of the curved part of the guide groove 101 gradually increases from the side closer to its horizontal part to the side farther away from its horizontal part. The curved parts of two adjacent guide grooves 101 are located between their horizontal parts. When the connector 8 is located in the curved part of an adjacent guide groove 101, the connector 8 supports the steel plate 111 through the roller 9, so that both sides of the steel plate 111 can also be bent, ensuring the accuracy of the test of the steel plate 111. The longitudinal length of the guide groove 101 is less than the longitudinal length of the slide groove 71.

[0027] like Figures 3-6As shown, the connecting member 8 includes two sliding members 81 symmetrically distributed front and rear. The sliding members 81 slide within adjacent sliding grooves 71 and adjacent guide grooves 101. The sliding members 81 are hinged to two I-shaped rods 82 symmetrically distributed vertically. The two I-shaped rods 82 symmetrically distributed front and rear are hinged together to a fixing member 83. The fixing member 83 is rotatably connected to the adjacent roller 9. A bidirectional push rod 12 is fixedly connected to the upper side of the sliding shaft 11. The two telescopic ends of the bidirectional push rod 12 are respectively fixedly connected to the adjacent guide plate 10. The sliding member 81 is provided with a vertical part. The guide plate 10 is used to press the adjacent sliding member 81. In the initial state, the guide plate 10 is in contact with the adjacent T-shaped plate 7. When the two guide plates 10 move away from each other, the two guide plates 10 drive the sliding member 81 away from the steel plate 111 through the vertical part of the sliding member 81. Two springs 84 are fixedly connected between the two fixed members 83 that are symmetrically distributed vertically and vertically. Two connecting sleeves 91 that are symmetrically distributed front and back are fixedly connected to the roller 9. The sliding member 81 is fixedly connected with a friction block 92 for rubbing the adjacent connecting sleeve 91. The connecting sleeve 91 is made of rubber and is used to increase the friction between the friction block 92 and the connecting sleeve 91.

[0028] In the initial state, the guide plate 10 is in contact with the adjacent T-shaped plate 7, the distance between the two adjacent rollers 9 is greater than the thickness of the steel plate 111, and the rollers 9 can rotate freely, facilitating the placement of the steel plate 111 between the two adjacent rollers 9. When this testing machine is needed to perform fatigue testing on the steel plate 111, the operator should follow... Figure 1 and Figure 2The steel plate 111 is placed between the symmetrically distributed rollers 9 according to the indicated positional relationship. Then, the operator activates the two bidirectional push rods 12. Taking the right bidirectional push rod 12 as an example, the telescopic end of the bidirectional push rod 12 pushes the two guide plates 10 away from each other. The front guide plate 10 moves forward away from the front T-shaped plate 7, and the rear guide plate 10 moves backward away from the rear T-shaped plate 7. The front guide plate 10 pulls the four front sliding parts 81 forward, and the rear guide plate 10 pulls the four rear sliding parts 81 backward. Taking the two rightmost sliding parts 81 as an example, the two sliding parts 81 bring the two fixed parts 83 closer together through the four I-shaped rods 82. The two springs 84 are compressed, and the two fixed parts 83 drive the rollers 9 and connecting sleeves on them. The two rollers 91 move closer to each other, clamping the steel plate 111 so that the steel plate 111 and the sliding member 81 are on the same horizontal plane, which facilitates the subsequent synchronous bending adjustment of both sides of the steel plate 111. As the two adjacent connecting sleeves 91 move closer to each other, the two adjacent connecting sleeves 91 will contact the friction block 92 between them and be compressed and deformed, thereby increasing the friction between the connecting sleeve 91 and the friction block 92, which makes it easier for the rollers 9 to clamp and fix the steel plate 111. After the steel plate 111 is fixed, the operator stops the two bidirectional push rods 12. At this time, all four sliding members 81 are located at the horizontal part of the adjacent guide groove 101, ensuring that both sides of the steel plate 111 are in a horizontal state, and preventing the sides from bending prematurely before the middle of the steel plate 111 has bent.

[0029] After the steel plate 111 is fixed, the middle part of the steel plate 111 is raised and bent. The specific operation is as follows: The operator starts the four first power modules to drive the four guide blocks 3 to move. The two guide blocks 3 on the right move to the left, and the two guide blocks 3 on the left move to the right. Taking the two guide blocks 3 on the right as an example, the two guide blocks 3 drive the two connecting plates 5 to move to the left through the two rotating shafts 4. The two connecting plates 5 drive the fixed shaft 6 to move to the left. The fixed shaft 6 drives the roller 9 to move to the left through the T-shaped plate 7 and the connecting piece 8. The two connecting plates 5 drive the sliding shaft 11, the bidirectional push rod 12 and the two guide plates 10 to move to the left. During the process of the rotating shaft 4 moving to the left, the operator starts the second power module to drive the rotating shaft 4 to rotate clockwise (to... Figure 2 (The direction of the main view is for reference). The rotating shaft 4 drives the steel plate 111 to bend to the right through the connecting plate 5, the fixed shaft 6, the T-shaped plate 7, the connecting piece 8 and the roller 9. The two rollers 9 move to the left to match the deformation of the bending of the steel plate 111, and do not push the steel plate 111 to the left.

[0030] As the steel plate 111 bends, its center gradually bulges upwards, and the overall degree of bending decreases from the center to both sides. Therefore, to accommodate this deformation, the following operation is performed: During the gradual bending of the steel plate 111, the operator activates two third power modules to move the left and right guide plates 10 away from each other. Taking the right guide plate 10 as an example, the guide plate 10 moves to the right, causing the four sliding parts 81 to enter the bent portion of the guide groove 101 from left to right. The right side of the steel plate 111 is then squeezed by the roller 9, and the degree of bending on its right side gradually decreases from left to right. When the steel plate 111 is bent to the test state, all four sliding parts 81 are located at the bent part of the guide groove 101, so that the bending degree of the right side of the steel plate 111 gradually decreases from left to right, which is more in line with the actual deformation state of the steel plate 111 during bending. Sixteen rollers 9 provide multi-point support and fixation for the steel plate 111, ensuring uniform force on both sides of the steel plate 111 and guaranteeing the accuracy of the stress change data in the middle of the steel plate 111. When the steel plate 111 is bent to the required maximum bending degree, the operator stops the first, second, and third power modules. During the bending process, stress data on the surface of steel plate 111 is collected by stress sensors installed on the steel plate 111. After the data collection is completed, the operator activates the first, second, and third power modules to reverse the above process, so that the steel plate 111 returns to flatness. Then, the above process is repeated to bend the steel plate 111 multiple times and collect data. After the fatigue test of the steel plate 111 is completed, the operator activates the two bidirectional push rods 12. Taking the right bidirectional push rod 12 as an example, the bidirectional push rod 12 drives the two guide plates 10 to approach the adjacent T-shaped plates 7. Taking the rightmost connecting... Taking connector 8 as an example, the two sliding parts 81 of connector 8 are no longer squeezed by the two guide plates 10. The spring 84 in the compressed state drives the two fixing parts 83 to move away from each other. The two fixing parts 83 drive the two rollers 9 to move away from each other. The two connecting sleeves 91 no longer contact the friction block 92. The two rollers 9 rotate freely, which makes it easier to remove the steel plate 111 from between the rollers 9. When the guide plate 10 contacts the adjacent T-shaped plate 7, the operator stops the two bidirectional push rods 12 and removes the steel plate 111. When fatigue testing is required on other steel plates 111, the above steps are repeated.

[0031] Example 2

[0032] Based on Example 1, a structural fatigue testing machine, such as Figure 1 , Figure 2 and Figure 6As shown, two fixed frames 2 are slidably connected to two symmetrically distributed correction plates 13. The two correction plates 13 are located on the left and right sides of the two bidirectional push rods 12, respectively. The two fixed frames 2 are jointly provided with a fourth power module for moving the two correction plates 13. The fourth power module includes two third electric slide rails (not shown in the figure) respectively installed on the corresponding fixed frames 2. The third electric slide rails are slidably connected to electric sliders fixed to the correction plates 13. The correction plates 13 are provided with two symmetrically distributed guide parts at the front and back. Taking the right correction plate 13 as an example, the distance between the two guide parts of the correction plate 13 gradually decreases from left to right. The distance between the right sides of the two guide parts of the correction plate 13 is equal to the width of the steel plate 111. The two correction plates 13 are used to center the steel plate 111. Different sizes of correction plates 13 can be adjusted and replaced according to the steel plate of different widths.

[0033] When the steel plate 111 is placed between the symmetrically distributed rollers 9, the steel plate 111 may shift or tilt, thus affecting the inspection process. Therefore, correcting the steel plate 111 beforehand is more beneficial for the inspection process. The specific operation is as follows: After the steel plate 111 is placed between the symmetrically distributed rollers 9, the operator first activates the fourth power module to drive the two correction plates 13 to move closer to each other. After the two correction plates 13 come into contact with the steel plate 111, they press the steel plate 111 through the guide parts on them, so that the steel plate 111 is gradually straightened. When the steel plate 111 is straightened, the operator activates the fourth power module to drive the two correction plates 13 to move away from each other. After the two correction plates 13 return to their initial positions, the operator stops the fourth power module.

[0034] The above description is merely an embodiment of the present invention and is not intended to limit the present invention. All equivalent substitutions made within the principles of the present invention should be included within the scope of protection of the present invention. Contents not described in detail in this invention are existing technologies known to those skilled in the art.

Claims

1. A structural fatigue testing machine, comprising an operating table (1), wherein the operating table (1) is equipped with symmetrically distributed fixed frames (2), the fixed frames (2) are slidably connected to symmetrically distributed guide blocks (3), the fixed frames (2) are provided with symmetrically distributed first power modules for driving adjacent guide blocks (3) to move, the guide blocks (3) are rotatably connected to rotating shafts (4), the guide blocks (3) are provided with second power modules for driving adjacent rotating shafts (4) to rotate, the rotating shafts (4) are fixedly connected to connecting plates (5), and fixed shafts (6) are fixedly connected between the connecting plates (5) that are symmetrical and close to different fixed frames (2), and the fixed shafts (6) are fixedly connected to symmetrically distributed T-shaped plates (7), characterized in that, The T-shaped plate (7) is provided with equally spaced sliding grooves (71). The sliding grooves (71) that are symmetrical and close to different fixed frames (2) are slidably connected to a connector (8). The connector (8) is rotatably connected to symmetrically distributed rollers (9). The symmetrically distributed rollers (9) are used to clamp the steel plate (111). The connecting plates (5) that are symmetrical and close to the different fixed frames (2) are slidably connected to a sliding shaft (11). The sliding shaft (11) is slidably connected to symmetrically distributed guide plates (10). The connecting plate (5) is provided with a third power module for driving the sliding shaft (11) to move. The guide plate (10) is provided with a guide groove (101). The connecting member (8) slides in the symmetrically distributed guide groove (101). The guide groove (101) is composed of a horizontal part and a curved part. The degree of curvature of the curved part of the guide groove (101) gradually increases from the side closer to its horizontal part to the side farther away from its horizontal part. The curved parts of the two guide grooves (101) corresponding to the same fixing frame (2) are located between the two horizontal parts. The longitudinal length of the guide groove (101) is less than the longitudinal length of the slide groove (71); The connector (8) includes symmetrically distributed sliding members (81), which slide in adjacent sliding grooves (71) and adjacent guide grooves (101). The sliding members (81) are hinged to symmetrically distributed I-shaped rods (82). The I-shaped rods (82) that are close to different sliding members (81) and symmetrically distributed are hinged to a fixing member (83). The fixing member (83) is rotatably connected to the adjacent roller (9). The sliding shaft (11) is fixedly connected to a bidirectional push rod (12), and the two telescopic ends of the bidirectional push rod (12) are respectively fixedly connected to the adjacent guide plate (10). The sliding member (81) is provided with a vertical part, and the guide plate (10) is used to press the vertical part of the adjacent sliding member (81). The symmetrically distributed fixing members (83) are fixedly connected with symmetrically distributed springs (84). The roller (9) is fixed with symmetrically distributed connecting sleeves (91), and the sliding member (81) is fixed with friction blocks (92) for rubbing adjacent connecting sleeves (91).

2. The structural fatigue testing machine according to claim 1, characterized in that, The connecting sleeve (91) is made of rubber.

3. The structural fatigue testing machine according to claim 1, characterized in that, The symmetrically distributed fixing frames (2) are slidably connected to symmetrically distributed correction plates (13). The symmetrically distributed correction plates (13) are located on both sides of the symmetrically distributed bidirectional push rods (12). The symmetrically distributed fixing frames (2) are jointly provided with a fourth power module for driving the symmetrically distributed correction plates (13) to move. The symmetrically distributed correction plates (13) are jointly used to center the steel plate (111).

4. A structural fatigue testing machine according to claim 3, characterized in that, The correction plate (13) is provided with symmetrically distributed guide parts, and the distance between the symmetrically distributed guide parts on the same correction plate (13) gradually decreases from the side closer to the bidirectional push rod (12) to the side farther away from the bidirectional push rod (12).

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