An apparatus for preparing a tensile test specimen of an elongated rod material and a method of use

Abstract

The application relates to an elongated rod material tensile test piece preparation device and a use method, which comprises the following steps: a main structure and a bottom plate, the main structure comprises a mold and a sample preparation table, two sample preparation tables are fixed up and down through support rods, holes are arranged in the centers of the two sample preparation tables, two molds are fixed at the holes of the sample preparation tables respectively, and the mold is divided into a split structure through a hinge. The application has the beneficial effects that: through the molds with different sizes, the test pieces with different size requirements can be adapted, the prepared elongated rod material tensile test piece has an end part which is easy to clamp, a cross pressure head is arranged at the end part of the rod part which is inserted into the mold, the connecting strength of the rod part and the end part pouring section is increased, and the problem that the rod part is pulled out from the clamp in the test process is further avoided; the main structure can rotate between the support columns through a rotating shaft, and the pouring in the two molds can be sequentially carried out.

Description

Technical Field

[0001] This invention belongs to the field of mechanics research, and in particular relates to an apparatus and method for preparing tensile specimens of slender rods. Background Technology

[0002] Tensile testing is a test used to determine the properties of materials under axial tensile load, and it is one of the commonly used methods for determining the mechanical properties of materials. National standards for tensile material testing have certain requirements for the shape and dimensions of tensile materials. However, in existing technologies, when the material diameter is less than 10 mm, the material is easily pulled out of the clamps of the universal testing machine during the test, causing test failure.

[0003] Therefore, it is proposed to invent a device and method for preparing slender rod tensile specimens to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an apparatus and method for preparing slender rod tensile specimens.

[0005] This apparatus for preparing tensile specimens of slender rods includes: a main structure and a base plate. The main structure includes a mold and a sample preparation table. The two sample preparation tables are fixed vertically by support rods. A hole is opened in the center of each of the two sample preparation tables. The two molds are fixed at the holes of the sample preparation tables respectively. The molds are divided into a split structure by connecting hinges.

[0006] The two ends of the rod are fixed by cross pressure heads and cast into the inside of two molds. Two cantilever clamps are rotatably connected to the two opposite support rods, and the two cantilever clamps are respectively fixed to the rods between the two molds.

[0007] The base plate is equipped with support columns, and the middle of the support rod is connected to the support column through a rotating shaft. The main structure rotates on the vertical plane between the two support columns.

[0008] Preferably, the mold includes a transition section and a fixed section. Both the transition section and the fixed section are divided into two split structures by a hinge. The transition section is conical and has a rod protrusion hole at the tip. An elastic rubber ring is provided inside the rod protrusion hole. The maximum diameter of the transition section is connected to one end of the fixed section by a thread.

[0009] Preferably, the end of the fixed section away from the transition section is inserted into the hole of the sample preparation table, and the fixed section and the sample preparation table are fixed by screws; both sample preparation tables are provided with mold covers on opposite sides to prevent the filling material in the mold from falling out, and the mold covers cover the holes of the sample preparation tables.

[0010] Preferably, the support rods are located at two opposite corners of the sample preparation stage, and the rotating shaft includes a hollow part and a central part. The hollow part is horizontally located in the middle of the support rod, and the central part is horizontally located on the two pillars. When the support rod and the pillars are connected, the hollow part is fitted onto the central part and rotates.

[0011] Preferably, one end of the cantilever clamp is rotatably connected to the support rod, and the other end has a groove I on its side. A fixing nut is provided at the outer end of the groove I. The rod is locked in the groove I. A pad is provided on the side of the groove I near the end. When the fixing nut is rotated, the pad moves in the groove I.

[0012] Preferably, a groove II is provided on the base plate, and a sample preparation table pre-reserved hole is provided on the sample preparation table corresponding to the groove II. When a fixing pin is inserted into both the groove II and the sample preparation table pre-reserved hole, the main structure is fixed between the two support columns.

[0013] Preferably, the cross indenter includes a cylindrical structure and side posts. The two cylindrical structures are connected to form an integral structure with an ∞-shaped cross section. The side posts are located on the surface of the cylindrical structure. The cylindrical structure is provided with steel plates circumferentially through elastic rubber. The ends of the rods are bent and pass through the two cylindrical structures of the cross indenter in sequence. The bending directions of the two ends of the rods are opposite.

[0014] The method of using this apparatus for preparing tensile specimens of slender rods includes the following steps:

[0015] Step 1: Insert the cross-shaped pressure head into both ends of the rod and bend it to fix it;

[0016] Step 2: Place both ends of the rod into the mold, and fix the two molds on the opposite surfaces of the two sample preparation tables respectively; use cantilever clamps to secure the rod; use fixing pins to fix the main structure;

[0017] Step 3: Fill the mold through the hole in the center of the sample preparation stage located above the main structure. After sealing the hole with the mold cover, pull out the fixing pin. Rotate the main structure with the rotating shaft and fix it with the fixing pin. Fill and seal another mold to form a slender rod tensile specimen.

[0018] Step 4: After the filling material in the mold has solidified, loosen the cantilever clamp, remove the slender rod tensile specimen and the mold from between the sample preparation table, and open the mold to take out the slender rod tensile specimen.

[0019] As a preferred option, in step two, the mold is divided into a gradient section and a fixed section. The gradient section is opened, the two ends of the rod are placed in and then closed. The end of the gradient section is then screwed into the fixed section through the thread, and the end of the rod and the cross pressure head are installed in the mold.

[0020] Preferably, the sample preparation platform and base plate at the bottom of the main structure are fixed by fixing pins, and the main structure is fixed between the two pillars; after the pins are pulled out, the main structure is rotated by a rotating shaft.

[0021] The beneficial effects of this invention are:

[0022] 1) The mold of the present invention can be opened into a split structure. With molds of different sizes, it can adapt to specimens with different size requirements. The slender rod tensile specimens produced have easy-to-clamp ends. By setting a cross pressure head at the end of the rod that extends into the mold, the connection strength between the rod and the end casting section is increased, further avoiding the problem of the rod being pulled out of the clamp during the test.

[0023] 2) The mold of the present invention is divided into a gradual section and a fixed section. The gradual section is conical, so that stress concentration will not occur when the slender rod tensile specimen is clamped, thus avoiding the impact on the test results.

[0024] 3) The device provided by the present invention is simple to install and easy to operate. The main structure can be rotated between the support columns by rotating the shaft, which facilitates the sequential casting of two molds. Attached Figure Description

[0025] Figure 1 A three-dimensional schematic diagram of an apparatus for preparing tensile specimens of slender rods;

[0026] Figure 2 This is a schematic diagram of the mold structure;

[0027] Figure 3 A schematic diagram of mold segmentation;

[0028] Figure 4 This is a schematic diagram showing the unfolded transition segment and the fixed segment from two different perspectives;

[0029] Figure 5 This is a schematic diagram of the sample preparation stage;

[0030] Figure 6 A schematic diagram showing the connection between the rotating shaft and the support column;

[0031] Figure 7 A schematic diagram showing the separation of the rotating shaft and the support column;

[0032] Figure 8 This is a schematic diagram of the cantilever clamp structure;

[0033] Figure 9 for Figure 8 Enlarged view of region A in the middle;

[0034] Figure 10 This is a schematic diagram of the specimen's structure;

[0035] Figure 11A schematic diagram showing the installation of cross-shaped pressure heads at both ends of a rod;

[0036] Figure 12 This is a structural schematic diagram of the rod;

[0037] Figure 13 This is a schematic diagram of the cross-shaped indenter.

[0038] Figure 14 This is a schematic diagram of the internal cross section of the cross indenter;

[0039] Figure 15 A schematic diagram showing the connection between the end of the rod and the cross-shaped pressure head;

[0040] Figure 16 This is a schematic diagram of the base plate.

[0041] Explanation of reference numerals in the attached drawings: 1. Mold; 2. Sample preparation table; 3. Support rod; 4. Fixing pin; 5. Cantilever clamp; 6. Rotating shaft; 7. Support column; 8. Base plate; 9. Gradient section; 10. Fixed section; 11. Connecting hinge; 12. Arc structure; 13. Fixed support leg; 14. Mold cover; 15. Wedge gasket; 16. Fixing bolt; 17. Rod; 18. Hollow part; 19. Shaft part; 20. Main structure; 21. Sample preparation table reserved hole; 22. Groove I; 23. Pad; 24. Fixing nut; 25. Groove II; 26. Elastic rubber ring; 27. Cross pressure head. Detailed Implementation

[0042] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0043] Example 1

[0044] As one example, such as Figures 1 to 16 As shown, this slender rod tensile specimen preparation device includes: a main structure 20 and a base plate 8. The main structure 20 includes a mold 1 and a sample preparation table 2. The two sample preparation tables 2 are fixed vertically by four support rods 3. A hole is opened in the center of each of the two sample preparation tables 2. The two molds 1 are fixed at the holes of the sample preparation tables 2 respectively. The molds 1 are divided into a split structure by a connecting hinge 11.

[0045] Each of the two sample preparation tables 2 has a mold cover 14 on its opposite side to prevent the filling material in the mold 1 from falling out. The mold cover 14 can rotate around the fixed support leg and cover the hole in the sample preparation table 2.

[0046] like Figures 10 to 15As shown, the two ends of the rod 17 are fixed and cast into the interior of two molds 1 by cross indenters 27 to form a slender rod tensile specimen. The cross indenter 27 includes a cylindrical structure and side posts. The two cylindrical structures are connected to form an integral structure with an ∞-shaped cross section. The side posts are located on the surface of the cylindrical structure to increase the adhesion between the rod 17 and the filling material in the mold 1 and to prevent the rod 17 from being pulled out during the test. The cylindrical structure is provided with steel plates in a circumferential direction through elastic rubber to form a barbed structure, which facilitates the insertion of the rod 17 and prevents it from being pulled out in the opposite direction after insertion. The ends of the rod 17 are bent and pass through the two cylindrical structures of the cross indenter 27 in sequence. The bending directions of the two ends of the rod 17 are opposite.

[0047] like Figure 8 and Figure 9 As shown, two opposing support rods 3 are rotatably connected to cantilever clamps 5, which are respectively secured to rods 17 between the two molds 1. One end of the cantilever clamp 5 is rotatably connected to the support rod 3, and the other end has a groove I 22 on its side. The rod 17 travels along the path of groove I 22 when the cantilever clamp 5 rotates along the cantilever. A fixing nut 24 is provided at the outer end of groove I 22, and the rod 17 is secured in groove I 22. A pad 23 is provided on the side of groove I 22 near the end. When the fixing nut 24 rotates, the pad 23 moves in groove I 22 to clamp the rod 17.

[0048] like Figure 6 , Figure 7 and Figure 16 As shown, a support column 7 is provided on the base plate 8. The support column 7 is rigidly connected to the floor 8. The two diagonally opposite support rods 3 are connected to the support column 7 via a rotating shaft 6. The main structure 20 rotates in the vertical plane between the two support columns 7. The rotating shaft 6 includes a hollow part 18 and a central part 19. The hollow part 18 is horizontally located in the middle of the support rod 3, and the central part 19 is horizontally located on the two support columns 7. When the support rod 3 and the support column 7 are connected, the hollow part 18 rotates on the central part 19.

[0049] The base plate 8 has a groove II 25, and the sample preparation table 2 has a sample preparation table reserved hole 21 corresponding to the groove II 25. When the groove II 25 and the sample preparation table reserved hole 21 are both inserted with a fixing pin 4, the main structure 20 is fixed between the two support columns 7 and will not rotate.

[0050] Example 2

[0051] As another embodiment, this second embodiment proposes a specific structure for mold 1 in this slender rod tensile specimen preparation device based on the first embodiment:

[0052] like Figures 2 to 4As shown, the mold 1 includes a gradient section 9 and a fixed section 10. Both the gradient section 9 and the fixed section 10 are divided into two split structures by a connecting hinge 11. The gradient section 9 is conical and has a rod extension hole at the tip. An elastic rubber ring 26 is provided inside the rod extension hole.

[0053] The gradient section 9 has a threaded section at its largest diameter, and one end of the fixed section 10 also has a thread inside. The thread and the threaded section of the gradient section 9 can be interlocked to form the mold 1 as a whole.

[0054] like Figure 1 and Figure 5 As shown, the end of the fixed section 10 away from the transition section 9 is inserted into the hole of the sample preparation table 2, and the fixed section 10 and the sample preparation table 2 are fixed by screws; the upper end of the fixed section 10 of the mold 1 is provided with two protruding arc structures, and the rod protrusion hole of the transition section 9 of the mold 1 has different sizes and is provided with a small diameter elastic rubber ring 26. It has multiple sizes to ensure sealing while adapting to small diameter rods 17 of different sizes.

[0055] The sample preparation table 2 has a protruding part inside the hole, which is compatible with the protruding part of the mold 1 fixing section 10, and the two can be fixed together by screws to achieve the purpose of fixing the mold 1.

[0056] It should be noted that the parts in this embodiment that are the same as or similar to those in Embodiment 1 can be referred to each other, and will not be repeated in this application.

[0057] Example 3

[0058] As another embodiment, this embodiment three provides a method for using the slender rod tensile specimen preparation device described in embodiments one and two, including the following steps:

[0059] Step 1: Insert both ends of rod 17 into the cross pressure head 27 and bend and fix them;

[0060] Step 2: Place both ends of rod 17 into mold 1, and fix the two molds 1 on the opposite surfaces of the two sample preparation tables 2 respectively; use cantilever clamps 5 to secure rod 17; use fixing pins 4 to fix the main structure 20;

[0061] Step 3: Fill the mold 1 with concrete through the hole in the center of the sample preparation table 2 located above the main structure 20. After sealing the hole with the mold cover 14, rotate the main structure 20 through the rotating shaft 6 and fix it with the fixing pin 4. Fill and seal the other mold 1 to form a slender rod tensile specimen.

[0062] Step 4: After the concrete in mold 1 has solidified, loosen the cantilever clamp 5, remove the slender rod tensile specimen and mold 1 from between the sample preparation table 2, and open mold 1 to remove the slender rod tensile specimen.

[0063] In the above process, the sample preparation platform 2 and the base plate 8 located at the bottom of the main structure 20 are fixed by the fixing pin 4, and the main structure 20 is fixed between the two support columns 7, keeping the sample preparation platform 2 on the construction side at the top; when it is necessary to rotate to the other side, the pin 4 is pulled out and the main structure 20 is rotated by the rotating shaft 6.

[0064] The middle member 17 of the slender rod tensile specimen is exposed, and the two ends of the two members 17 are anchored in concrete with a tapered gradient and a cylindrical structure.

[0065] Example 4

[0066] As another embodiment, this fourth embodiment, based on the third embodiment, proposes a more specific method for using the apparatus for preparing slender rod tensile specimens.

[0067] In step one, one end of the rod 17 is inserted into the cylindrical structure on one side of the cross-shaped pressure head 27 along the direction of the barbs, and then the inserted rod 17 is bent so that it extends along the other side of the cylindrical structure of the cross-shaped pressure head 27, forming a bend. The same operation is performed on the other end of the rod 17, so that the bend directions of the two ends of the rod 17 are opposite.

[0068] In step two, open mold 1 and disassemble mold 1 into gradient section 9 and fixed section 10. Open gradient section 9, put the end of rod 17 in and close it. Then screw the end of gradient section 9 into fixed section 10 through threads and install the end of rod 17 and cross pressure head 27 into mold 1.

[0069] In step four, after separating the gradient section 9 and the fixed section 10, the slender rod tensile specimen can be taken out.

[0070] It should be noted that the parts in this embodiment that are the same as or similar to those in Embodiment 3 can be referred to each other, and will not be repeated in this application.

[0071] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

Claims

1. An apparatus for preparing a tensile test specimen of an elongated rod material, characterized by include: The main structure (20) and the base plate (8) include a mold (1) and a sample making table (2). The two sample making tables (2) are fixed up and down by a support rod (3). The two sample making tables (2) have holes in the center. The two molds (1) are fixed at the holes of the sample making tables (2). The molds (1) are divided into a split structure by a connecting hinge (11). The two ends of the rod (17) are fixed by the cross pressure head (27) and cast into the interior of the two molds (1). The two opposite support rods (3) are respectively rotatably connected to the cantilever clamps (5), and the two cantilever clamps (5) are respectively fixed on the rod (17) between the two molds (1). The base plate (8) is provided with a support column (7), and the middle part of the support rod (3) is connected to the support column (7) through a rotating shaft (6). The main structure (20) rotates on the vertical plane between the two support columns (7).

2. The apparatus of claim 1 wherein, The mold (1) includes a transition section (9) and a fixed section (10). Both the transition section (9) and the fixed section (10) are divided into two split structures by a connecting hinge (11). The transition section (9) is conical and has a rod protrusion hole at the tip. An elastic rubber ring (26) is provided inside the rod protrusion hole. The maximum diameter of the transition section (9) and one end of the fixed section (10) are connected by a thread.

3. The apparatus of claim 2 wherein, The fixed section (10) is inserted into the hole of the sample preparation table (2) at the end away from the transition section (9). The fixed section (10) and the sample preparation table (2) are fixed by screws. The opposite sides of the two sample preparation tables (2) are provided with mold covers (14) to prevent the filling material in the mold (1) from falling out. The mold covers (14) cover the hole of the sample preparation table (2).

4. The apparatus of claim 1 wherein, The support rod (3) is located at two opposite corners of the sample preparation table (2). The rotating shaft (6) includes a hollow part (18) and a central part (19). The hollow part (18) is horizontally located in the middle of the support rod (3), and the central part (19) is horizontally located on two support columns (7). When the support rod (3) and the support columns (7) are connected, the hollow part (18) is sleeved on the central part (19) and rotates.

5. The apparatus of claim 1 wherein, One end of the cantilever clamp (5) is rotatably connected to the support rod (3), and the other end has a groove I (22) on its side. A fixing nut (24) is provided at the outer end of the groove I (22). The rod (17) is stuck in the groove I (22). A pad (23) is provided on the side of the groove I (22) near the end. When the fixing nut (24) rotates, the pad (23) moves in the groove I (22).

6. The apparatus of claim 1 wherein, The base plate (8) has a groove II (25), and the sample preparation table (2) has a sample preparation table reserved hole (21) corresponding to the groove II (25). When the groove II (25) and the sample preparation table reserved hole (21) are both inserted with fixing pins (4), the main structure (20) is fixed between the two support columns (7).

7. The apparatus for preparing slender rod tensile specimens according to claim 1, characterized in that, The cross pressure head (27) includes a cylindrical structure and side columns. The two cylindrical structures are connected to form an integral structure with an ∞-shaped cross section. The side columns are located on the surface of the cylindrical structure. The cylindrical structure is provided with steel plates in the circumferential direction through elastic rubber. The ends of the rod (17) are bent and pass through the two cylindrical structures of the cross pressure head (27) in sequence. The bending directions of the two ends of the rod (17) are opposite.

8. The method of using an apparatus for preparing an elongated rod material tensile test specimen according to any one of claims 1 to 7, wherein Includes the following steps: Step 1: Insert the two ends of the rod (17) into the cross-shaped pressure head (27) and bend and fix them; Step 2: Place both ends of the rod (17) into the mold (1), and fix the two molds (1) on the opposite surfaces of the two sample preparation tables (2); use the cantilever clamp (5) to secure the rod (17); use the fixing pin (4) to fix the main structure (20); Step 3: Fill the mold (1) through the hole in the center of the sample preparation table (2) above the main structure (20), seal the hole with the mold cover (14), pull out the fixing pin (4), rotate the main structure (20) with the rotating shaft (6) and fix it with the fixing pin (4), fill and seal the other mold (1) to form a slender rod tensile specimen; Step 4: After the filling material in the mold (1) solidifies, loosen the cantilever clamp (5), remove the slender rod tensile specimen and the mold (1) from between the sample preparation table (2), and open the mold (1) to take out the slender rod tensile specimen.

9. The method of using an elongated rod material tensile specimen preparation apparatus of claim 8, wherein, In step two, the mold (1) is split into a gradient section (9) and a fixed section (10). The gradient section (9) is opened, and the two ends of the rod (17) are put in and then closed. The end of the gradient section (9) is screwed into the fixed section (10) through the thread, and the end of the rod (17) and the cross pressure head (27) are installed in the mold (1).

10. The method of using an elongated rod material tensile specimen preparation apparatus of claim 8, wherein, The sample preparation platform (2) and the base plate (8) at the bottom of the main structure (20) are fixed by fixing pin (4), and the main structure (20) is fixed between two pillars (7); after the pin (4) is pulled out, the main structure (20) is rotated by rotating shaft (6).

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