Clamping device for crack propagation detection

Abstract

The utility model discloses a clamping device for crack propagation detection, which comprises a testing machine body, and a clamp assembly and a lifting assembly which are arranged on the testing machine body, the clamp assembly comprises a fixed part and a movable part, the movable part comprises a frame, the frame is n-shaped, reinforcing cylinders are symmetrically arranged on the frame, and the reinforcing cylinders are arranged on the fixed part. According to the clamping device for crack propagation detection, the fixed part and the movable part are arranged, the independently arranged movable part is utilized, the connection process of a CT sample is facilitated, the clamping effect is improved, and the clamping device has the advantages that the clamping device is simple in structure, convenient to use and high in practicability. In the process, a CT sample does not need to be lifted, the installation process is easier and more labor-saving, the connection process of the fixed part and the movable part can be completed by matching with the lifting assembly to simply move the machine shell up and down, and the whole device has good practicability and reliability and can be widely applied to the field of material mechanical property testing.

Description

Technical Field

[0001] The utility model relates to the technical field of crack extension detection, in particular to a clamping device for crack extension detection. Background Art

[0002] Generally, there are three stages of fatigue in metal materials, namely fatigue crack initiation, fatigue crack propagation and fatigue fracture. Fatigue crack propagation refers to the growth of fatigue cracks in the propagation zone, which is the second stage of fatigue. Under the action of continuous stress, fatigue cracks develop longitudinally with the extension of action time, and the mechanical properties of the material gradually decrease, eventually leading to complete fracture. Therefore, in order to increase the application life of metal materials, it is of great practical significance to study the mechanism of residual stress on fatigue crack initiation and propagation.

[0003] The main applications of fatigue analysis based on fracture mechanics include determining the maximum tolerable initial flaw size for design life (usually involving welds), calculating the crack growth life for known or assumed crack sizes, and planning inspection intervals. In order to accurately predict crack growth using this method, tests must be performed to obtain the fatigue crack growth rate (FCGR) of the material under appropriate environmental conditions. FCGR testing requires the use of standard specimen geometries, where compact tension (CT) (such as the attached Figure 1 ) is the most commonly used shape. During the test, the CT specimen is clamped by passing the fixture pin on the fatigue testing machine through the pin hole of the CT specimen.

[0004] In the existing testing process, it is quite laborious to install the CT sample on the fixture. First, the CT sample itself is heavy and inconvenient to control. In addition, when the operator lifts the CT sample in the air, it is difficult to insert the pin on the fixture into the pin hole of the CT sample at one time, which brings certain inconveniences to the testing process. Utility Model Content

[0005] In order to solve the deficiencies mentioned in the above-mentioned background technology, the purpose of the utility model is to provide a clamping device for crack extension detection. By setting a fixed part and a movable part and utilizing a separately set movable part, the connection process of the CT sample is facilitated. There is no need to hold the CT sample during the process, and the installation process is easier and more labor-saving. The connection process of the fixed part and the movable part can be completed by simply moving the casing up and down with the lifting assembly. The whole device has good practicality and reliability and can be widely used in the field of material mechanical properties testing.

[0006] The purpose of the utility model can be achieved through the following technical solutions:

[0007] A clamping device for crack propagation detection, comprising a testing machine body, a fixture assembly and a lifting assembly arranged on the testing machine body. The fixture assembly includes a fixed part and a movable part. The movable part includes a frame, which is in a U-shaped. Reinforcing cylinders are symmetrically arranged on the frame. A stress rod is slidably connected inside the reinforcing cylinder. Hanging brackets are symmetrically arranged at the top of the frame. A rhombic telescopic structure is arranged inside the hanging bracket. The rhombic telescopic structure includes four connecting rods and four rotating shafts. The four connecting rods are arranged in a way that the head and tail are connected in sequence. Adjacent connecting rods are rotatably connected by rotating shafts. When installing the movable part, first squeeze the two rotating shafts in the left-right direction, thereby squeezing the first spring, and making the two rotating shafts connected to the stress rod move away from each other, so as to pull out the stress rod from the frame. Then place the frame on the top of the CT specimen, and slide the frame until the stress rod enters the pin hole of the CT specimen under the restoring force of the first spring. By setting a separate movable part, it is convenient for the connection process of the CT specimen. During the process, there is no need to hold the CT specimen, and the installation process is more labor-saving and easier.

[0008] Further preferably, two symmetrically arranged rotating shafts are respectively fixedly connected to two different stress rods, and a first spring is arranged between the other two rotating shafts.

[0009] Further preferably, the fixed part includes a fixed plate. Cavities are symmetrically arranged inside the fixed plate. A rotating rod is arranged inside the cavity. A balance rod is rotatably connected to the rotating rod. One end of the balance rod is rotatably connected to a push rod. One end of the push rod penetrates through the fixed plate and extends to the lower part of the fixed plate. One end of the balance rod is rotatably connected to a pull rod. One end of the pull rod penetrates through the fixed plate and extends to the lower part of the fixed plate.

[0010] Further preferably, the fixed part further includes a bracket. A sliding rod is fixedly connected to the bracket. Hanging rods are symmetrically sleeved on the sliding rod. The inside of the hanging rod is a hollow structure. A second spring is arranged inside the hanging rod.

[0011] Further preferably, a barb is arranged at the bottom end of the pull rod. A limiting hole is formed on the hanging rod. When the barb is located in the limiting hole, the distance between the end faces of the two mutually separated hanging rods is smaller than the distance between the left and right end faces of the fixed plate.

[0012] Further preferably, the lifting assembly includes a hydraulic rod. A telescopic lifting platform is fixedly connected to the output end of the hydraulic rod. Through the telescopic movement of the hydraulic rod, the overall lifting of the CT specimen can be driven, realizing the rapid clamping and unloading of the CT specimen, and reducing the physical consumption of the operator.

[0013] The beneficial effects of the present utility model:

[0014] 1. The utility model provides a fixed part and a movable part, and utilizes a separately provided movable part to facilitate the connection process of the CT sample. During the process, the CT sample does not need to be held, and the installation process is easier and more labor-saving. The connection process of the fixed part and the movable part can be completed by simply moving the casing up and down with the lifting assembly. The whole device has good practicality and reliability and can be widely used in the field of material mechanical properties testing;

[0015] 2. The utility model can drive the overall lifting and lowering of the CT sample through the telescopic movement of the hydraulic rod, realize the rapid clamping and unloading of the CT sample, and reduce the physical consumption of the operator. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The utility model is further described below in conjunction with the accompanying drawings.

[0017] Figure 1 It is a structural schematic diagram of a CT specimen in the prior art;

[0018] Figure 2 It is a schematic diagram of the overall structure of the utility model;

[0019] Figure 3 It is a schematic diagram of the structure of the fixed parts and the movable parts in the utility model;

[0020] Figure 4 It is a schematic diagram of the structure of the movable parts in the utility model;

[0021] Figure 5 It is a cross-sectional view of the fixed plate structure in the utility model.

[0022] In the figure:

[0023] 1. Testing machine body; 2. Fixed parts; 3. Movable parts; 4. Frame; 5. Reinforcement tube; 6. Force rod; 7. Hanging bracket; 8. Diamond telescopic structure; 9. Connecting rod; 10. Rotating shaft; 11. First spring; 12. Fixed plate; 13. Cavity; 14. Rotating rod; 15. Balance rod; 16. Push rod; 17. Pull rod; 18. Bracket; 19. Sliding rod; 20. Hanging rod; 21. Second spring; 22. Barb; 23. Limiting hole; 24. Hydraulic rod; 25. Telescopic lifting platform. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] In the description of the present utility model, it should be understood that terms such as "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "periphery", etc. indicating orientation or positional relationships are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.

[0026] As Figure 2-5 shown, a clamping device for crack propagation detection includes a testing machine body 1, and a fixture assembly and a lifting assembly provided on the testing machine body 1. The fixture assembly includes a fixed member 2 and a movable member 3. The movable member 3 includes a frame 4, and the frame 4 is in a U-shaped configuration. Reinforcing cylinders 5 are symmetrically arranged on the frame 4. A stress rod 6 is slidably connected inside the reinforcing cylinder 5. Hanging brackets 7 are symmetrically arranged at the top of the frame 4. A rhombic telescopic structure 8 is arranged inside the hanging bracket 7. The rhombic telescopic structure 8 includes four connecting rods 9 and four rotating shafts 10. The four connecting rods 9 are arranged in a head-to-tail connection manner, and adjacent connecting rods 9 are rotatably connected through the rotating shaft 10. When installing the movable member 3, first squeeze the two rotating shafts 10 in the left-right direction, thereby squeezing the first spring 11, and making the two rotating shafts 10 connected to the stress rod 6 move away from each other, thereby pulling out the stress rod 6 from the frame 4. Then place the frame 4 on the top of the CT specimen, and slide the frame 4 until the stress rod 6 enters the pin hole of the CT specimen under the restoring force of the first spring 11. By providing a separate movable member 3, the connection process of the CT specimen is facilitated, and it is not necessary to hold the CT specimen during the process, and the installation process is more labor-saving and easier.

[0027] Two of the symmetrically arranged rotating shafts 10 are respectively fixedly connected to two different stress rods 6, and a first spring 11 is arranged between the other two rotating shafts 10.

[0028] The fixed member 2 includes a fixing plate 12. Cavities 13 are symmetrically arranged inside the fixing plate 12. A rotating rod 14 is arranged inside the cavity 13. A balance rod 15 is rotatably connected to the rotating rod 14. One end of the balance rod 15 is rotatably connected to a push rod 16. One end of the push rod 16 penetrates through the fixing plate 12 and extends below the fixing plate 12. One end of the balance rod 15 is rotatably connected to a pull rod 17. One end of the pull rod 17 penetrates through the fixing plate 12 and extends below the fixing plate 12.

[0029] The fixed member 2 further includes a bracket 18. A sliding rod 19 is fixedly connected to the bracket 18. Hanging rods 20 are symmetrically sleeved on the sliding rod 19. The inside of the hanging rod 20 is a hollow structure, and a second spring 21 is arranged inside the hanging rod 20.

[0030] A barb 22 is provided at the bottom end of the pull rod 17, and a limiting hole 23 is provided on the hanging rod 20. When the barb 22 is located in the limiting hole 23, the distance between the end faces of the two hanging rods 20 that are away from each other is smaller than the distance between the left and right end faces of the fixing plate 12.

[0031] The lifting assembly includes a hydraulic rod 24, and the output end of the hydraulic rod 24 is fixedly connected to a telescopic lifting platform 25. Through the telescopic movement of the hydraulic rod 24, the overall lifting of the CT sample can be driven, so that the CT sample can be quickly clamped and unloaded, reducing the physical consumption of the operator.

[0032] Working principle:

[0033] Before using the device, first install the fixing part 2 on the driving unit of the testing machine body 1, then place the CT sample on the telescopic lifting platform 25, and then install the two movable parts 3 on the upper and lower sides of the CT sample respectively. When installing the movable parts 3, first squeeze the two rotating shafts 10 in the left and right directions, thereby squeezing the first spring 11, and making the two rotating shafts 10 connected to the force-bearing rod 6 move away from each other, so as to pull the force-bearing rod 6 out of the frame 4, and then place the frame 4 on the top of the CT sample, and slide the frame 4 until the force-bearing rod 6 enters the pin hole of the CT sample under the restoring force of the first spring 11. By setting a separate movable part 3, the connection process of the CT sample is facilitated, and the CT sample does not need to be lifted during the process, and the installation process is easier and more economical. Force is applied, and then the CT sample is lifted by the hydraulic rod 24. When it reaches the appropriate position, the telescopic lifting platform 25 is pulled to move the CT sample to the bottom of the upper fixed part 2. Then the CT sample is lifted again until the hanger 7 contacts the push rod 16, and the push rod 16 is pushed to move into the cavity 13, thereby driving the pull rod 17 at the other end of the balance bar 15 to move out of the cavity 13, so that the barb 22 is disengaged from the limiting hole 23. Under the restoring force of the second spring 21, the hanger rod 20 slides on the slide bar 19 in the direction away from the bracket 18, thereby limiting the hanger 7 between the fixed plate 12 and the hanger rod 20, thereby fixing the upper movable part 3 and the upper fixed part 2. Then the above installation process is repeated to fix the lower movable part 3 and the fixed part 2 in turn.

[0034] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0035] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, and these changes and improvements fall within the scope of the utility model to be protected.

Claims

1. A clamping device for crack extension detection, characterized in that: It includes a testing machine body (1), a fixture assembly and a lifting assembly arranged on the testing machine body (1). The fixture assembly includes a fixed part (2) and a movable part (3). The movable part (3) includes a frame (4). The frame (4) is in a U shape. Reinforcing cylinders (5) are symmetrically arranged on the frame (4). A stress rod (6) is slidably connected inside the reinforcing cylinder (5). Hanging brackets (7) are symmetrically arranged at the top of the frame (4). A diamond-shaped telescopic structure (8) is arranged inside the hanging bracket (7). The diamond-shaped telescopic structure (8) includes four connecting rods (9) and four rotating shafts (10). The four connecting rods (9) are arranged in a way that their heads and tails are connected in sequence. Adjacent connecting rods (9) are rotatably connected by the rotating shafts (10).

2. The clamping device for crack extension detection according to claim 1, characterized in that: Two symmetrically arranged rotating shafts (10) are respectively fixedly connected to two different stress rods (6), and a first spring (11) is arranged between the other two rotating shafts (10).

3. The clamping device for crack extension detection according to claim 1, characterized in that: The fixed part (2) includes a fixing plate (12). Cavities (13) are symmetrically arranged inside the fixing plate (12). A rotating rod (14) is arranged inside the cavity (13). A balance rod (15) is rotatably connected to the rotating rod (14). One end of the balance rod (15) is rotatably connected to a push rod (16). One end of the push rod (16) penetrates through the fixing plate (12) and extends below the fixing plate (12). One end of the balance rod (15) is rotatably connected to a pull rod (17). One end of the pull rod (17) penetrates through the fixing plate (12) and extends below the fixing plate (12).

4. The clamping device for crack extension detection according to claim 3, characterized in that: The fixed part (2) further includes a bracket (18). A sliding rod (19) is fixedly connected to the bracket (18). Hanging rods (20) are symmetrically sleeved on the sliding rod (19). The inside of the hanging rod (20) is a hollow structure. A second spring (21) is arranged inside the hanging rod (20).

5. The clamping device for crack extension detection according to claim 4, characterized in that: A barb (22) is arranged at the bottom end of the pull rod (17). A limiting hole (23) is formed on the hanging rod (20). When the barb (22) is located in the limiting hole (23), the distance between the mutually remote end faces of the two hanging rods (20) is less than the distance between the left and right end faces of the fixing plate (12).

6. The clamping device for crack extension detection according to claim 1, characterized in that: The lifting assembly includes a hydraulic rod (24). The output end of the hydraulic rod (24) is fixedly connected to a telescopic lifting platform (25).

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