Anti-clamping stagnation and anti-falling four-point bending experiment clamp and device

Abstract

The utility model belongs to the technical field of testing devices, and relates to a four-point bending experiment clamp and device capable of preventing clamping stagnation and falling. The clamp comprises a base which defines a cavity with a downward opening and is provided with a pair of first supporting points extending upwards towards the cavity; the pressing block is contained in the cavity, a pair of second supporting points extending downwards are arranged on the lower surface of the pressing block, the distance between the first supporting points is larger than that between the second supporting points, and a bent sample is arranged between the first supporting points and the second supporting points to form four-point supporting; the loading stud is arranged to penetrate through the base and the pressing block to extend; and the anti-falling column is connected to the loading stud and is arranged to be matched with a pressing block so as to limit the axial displacement of the loading stud. According to the four-point bending experiment clamp disclosed by the utility model, the stress application process can be smoothly implemented, the clamping stagnation phenomenon of the stud or the pressing block is avoided, and the falling phenomenon of the pressing block is avoided in the stress unloading process.

Description

Technical Field

[0001] This utility model belongs to the field of testing device technology, and relates to a four-point bending test fixture and device that prevents jamming and detachment. Background Technology

[0002] The four-point bending test is a commonly used method for testing the mechanical properties of materials. It can be used to determine performance parameters such as bending strength and elastic modulus. Compared to three-point bending, four-point bending creates a pure bending region in the middle section of the specimen, reducing the influence of shear force and allowing the test results to more accurately reflect the true bending characteristics of the material. In the experiment, the specimen is placed on a fixture with four support points, and external forces are applied at two loading points to induce bending deformation in the specimen.

[0003] The hydrogen embrittlement test is a method for evaluating the resistance of metallic materials to brittle fracture in a hydrogen environment. It requires placing a compressed specimen, along with a fixture, in a hydrogen environment to observe delayed cracking. A four-point bending test fixture of 100... Figure 1 As shown, it typically consists of a base 110, a pressure block 120, and a loading bolt 130. The loading bolt 130 has threads at its bottom and connects to the pressure block 120 by screwing it into a threaded hole on top of the pressure block 120. Furthermore, the loading bolt 130 acts as a pressure transmission element, bending the sample by rotating the loading bolt. This often leads to jamming and detachment of the bolt or pressure block when applying or unloading stress in the existing fixture 100, causing considerable inconvenience to the experiment.

[0004] Therefore, there is an urgent need for a four-point bending test fixture that prevents jamming and detachment for evaluating hydrogen embrittlement performance. Utility Model Content

[0005] In view of this, the present invention proposes a four-point bending test fixture and device to prevent jamming and detachment.

[0006] To solve at least one of the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] According to one aspect of this utility model, a four-point bending test fixture for preventing jamming and detachment is provided, comprising: a base defining a downwardly opening cavity and having a pair of first support points extending upward toward the cavity; a pressure block housed within the cavity and having a pair of downwardly extending second support points on its lower surface, wherein the distance between the first support points is greater than the distance between the second support points, and a bending specimen is disposed between the first support points and the second support points to form four-point support; a loading stud configured as a finely ground column extending through the base and the pressure block; and an anti-detachment column connected to the loading stud and configured to cooperate with the pressure block to limit the axial displacement of the loading stud.

[0008] According to one embodiment of the present invention, the base includes: a base body extending laterally and having a first through hole in the middle; a pair of support portions extending symmetrically downward from both ends of the base body and forming an L-shaped structure opposite to each other; and a pair of protrusions extending symmetrically downward from the base body, wherein the distance between the pair of protrusions is less than the distance between the pair of support portions.

[0009] According to one embodiment of the present invention, the base further includes a pair of fixing holes, configured to fix the base to a fixing fixture.

[0010] According to one embodiment of the present invention, the clamp further includes a support column, wherein a pair of support portions are respectively provided with a first groove, and the support column is disposed in the first groove to form a first support point; a second groove is provided at the bottom of the pressure block, and the support column is disposed in the second groove to form a second support point.

[0011] According to one embodiment of the present invention, the loading stud includes: a loading end configured to connect to a loading device; a rod extending through the base; and a connecting end extending through the pressure block and connected to the anti-detachment stud; wherein the diameter of the rod is larger than the diameter of the connecting end.

[0012] According to one embodiment of the present invention, a second through hole is provided through the middle of the pressure block. The second through hole includes: a first section of the second through hole having a first aperture that matches the connecting end; and a second section of the second through hole having a second aperture that matches the anti-falling column; wherein the first aperture is smaller than the second aperture.

[0013] According to one embodiment of the present invention, the clamp includes a flat-head screw, wherein the bottom of the connecting end is provided with a threaded hole, the anti-drop post is provided with a third through hole (252), and the flat-head screw (260) passes through the third through hole (252) to connect the anti-drop post (250) to the connecting end.

[0014] According to one embodiment of the present invention, the connecting end is provided with a radially recessed platform, and the anti-falling column is provided with a first sinkhole that matches the section where the platform is located.

[0015] According to one embodiment of the present invention, the anti-loosening post is provided with a second recess that matches the head of the flat-head screw.

[0016] According to another aspect of the present invention, a four-point bending test device for preventing jamming and detachment is provided, comprising the clamps as described above.

[0017] By adopting the above technical solution, the present invention has at least one of the following advantages compared with the prior art:

[0018] (1) The four-point bending fixture of this utility model has been finely ground on the outer surface of the lower end of the loading stud so that the stress application process can be carried out smoothly and there will be no jamming of the stud or the pressure block.

[0019] (2) The four-point bending fixture of this utility model effectively limits the axial displacement of the loading stud by cooperating with the anti-drop column and the pressure block, so that the pressure block will not fall off during the stress unloading process. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a prior art four-point bending test fixture;

[0022] Figure 2 A cross-sectional view of a four-point bending test fixture provided in an embodiment of this utility model;

[0023] Figure 3 A side view of a four-point bending test fixture provided in an embodiment of this utility model;

[0024] Figure 4 A schematic diagram of the base of a four-point bending test fixture provided in an embodiment of this utility model;

[0025] Figure 5 A schematic diagram of the pressure block of a four-point bending test fixture provided in an embodiment of this utility model;

[0026] Figure 6 A schematic diagram of the loading stud of the four-point bending test fixture provided in one embodiment of this utility model;

[0027] Figure 7 This is a schematic diagram of the anti-fall-off column of the four-point bending test fixture provided in one embodiment of the present invention.

[0028] In the picture,

[0029] 100. Existing four-point bending test fixture; 110. Base; 120. Pressure block; 130. Loading bolt;

[0030] 200. Four-point bending test fixture of this utility model; 210. Base; 211. Base body; 2111. First through hole; 2112. Fixing hole; 212. Protrusion; 213. Support part; 2131. First groove; 220. Pressure block; 221. Second through hole; 222. Second groove; 230. Support column; 240. Loading stud; 241. Loading end; 242. Column rod; 243. Connecting end; 2431. Threaded hole; 2432. Platform; 250. Anti-falling column; 251. First recess; 252. Third through hole; 260. Flat head screw;

[0031] 300. Bending specimen. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be further described in detail below with reference to specific examples and accompanying drawings.

[0033] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the present invention. Accordingly, all such modifications should be included within the scope of this invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the present invention.

[0034] According to one aspect of this utility model, a four-point bending test fixture 200 for preventing jamming and detachment is proposed, such as... Figure 2 and Figure 3 As shown, the overall structure includes: a base 210, a pressure block 220, a loading stud 240, and an anti-drop post 250. Specifically, the base 210 defines a downward-opening cavity that can accommodate the pressure block 220 and the bending specimen 300. The base 210 is provided with a pair of first support points extending upward toward the cavity. The pressure block 220 is accommodated within the cavity and has a pair of downward-extending second support points on its lower surface. The distance between the first support points is greater than the distance between the second support points, and the bending specimen 300 is positioned between the first and second support points to form a four-point support. The loading stud 240 is configured to extend through the base 210 and the pressure block 220. The anti-drop post 250 is connected to the loading stud 240 and configured to cooperate with the pressure block 220 to limit the axial displacement of the loading stud 240.

[0035] like Figure 4As shown, the base 210 includes a base body 211 and a pair of support portions 213. Specifically, the base body 211 extends laterally and has a first through hole 2111 through its center for the loading stud 240 to pass through. The pair of support portions 213 extend symmetrically downward from both ends of the base body 211 and are arranged in an L-shaped structure opposite each other, defining a cavity together with the bottom surface of the base body 211. Preferably, the base 210 may also include a pair of protrusions 212 extending symmetrically downward from the base body 211. The distance between the pair of protrusions 212 is less than the distance between the pair of support portions 213, and the space formed between them and the bottom surface of the base body 211 can be used to accommodate the pressure block 220. More preferably, the base body 211 may also include a pair of fixing holes 2112, which can be used to fix the base 210 to a corresponding fixture according to experimental needs. In an embodiment of this utility model, a pair of fixing holes 2112 extend through the thickness direction of the base body 211. In a hydrogen embrittlement test, a bracket extending through the fixing holes 2112 can be used to place the clamp 200 together with the bent sample 300 in a hydrogen environment.

[0036] like Figure 5 As shown, a second through hole 221 is provided through the middle of the pressure block 220 for the loading stud 240 to pass through. The clamp 200 according to this invention may also include a support column 230. The support column 230 may be a rod-shaped component made of ceramic rod or other high-strength insulating material, used to provide a support point. In an embodiment of this invention, a pair of support portions 213 may each have a first groove 2131, and the support column 230 is disposed in the first groove 2131 to form a first support point. Similarly, a second groove 222 is provided at the bottom of the pressure block 220, and the support column 230 is disposed in the second groove 222 to form a second support point. Preferably, the number and position of the first groove 2131 and the second groove 222 can be increased, decreased, or changed, so as to change the position of the support point by changing the groove where the support column 230 is located, to meet different experimental requirements.

[0037] In this utility model, such as Figure 6As shown, the loading stud 240 is a precision-ground cylindrical structure, specifically a cylindrical structure with a high-precision ground outer surface. On one hand, the highly smooth surface of the precision-ground cylindrical structure ensures that pressure is evenly distributed on the contact surface during pressure transmission, preventing excessive local pressure and ensuring uniform pressure distribution, thus completely avoiding jamming. On the other hand, the smooth surface minimizes energy loss during pressure transmission, effectively improving transmission efficiency. Just like in a hydraulic system, a precision-ground cylindrical structure effectively transmits liquid pressure, reducing pressure loss. Further, the loading stud 240 includes a rod 242 and loading ends 241 and connecting ends 243 located at both ends of the rod 242. Specifically, the loading end 241 is configured to connect to a loading device and can be configured as a hexagonal prism structure for easy connection to the loading device. The rod 242 extends through the base 210 and can match the diameter of the first through hole 2111. The connecting end 243 extends through the pressure block 220 and connects to the anti-detachment post 250. Preferably, the diameter of the stud 242 can be larger than the diameter of the connecting end 243, that is, larger than the diameter of the second through hole 221, so as to prevent the loading stud 240 from moving downward along its axis.

[0038] Combination Figure 2 and Figure 6 The second through hole 221 of the pressure block 220 includes: a first section of the second through hole and a second section of the second through hole. Specifically, the first section of the second through hole has a first diameter that matches the connecting end 243; the second section of the second through hole has a second diameter that matches the anti-detachment post 250; the first diameter is smaller than the second diameter to prevent the loading stud 240 from moving upward along its axis. Preferably, the clamp 200 may include a flat-head screw 260. The bottom of the connecting end 243 of the loading stud 240 is provided with a threaded hole 2431, and the anti-detachment post 250 is provided with a third through hole 252. The flat-head screw 260 passes through the third through hole 252 to connect the anti-detachment post 250 to the connecting end 243. Alternatively, those skilled in the art can use other methods to connect the loading stud 240 and the anti-detachment post 250.

[0039] Combination Figure 6 and Figure 7 The connecting end 243 of the loading stud 240 may be provided with at least one radially recessed platform 2432, and the anti-drop post 250 is provided with a first countersunk groove 251 that matches the section where the platform 2432 is located. Thus, after the section where the platform 2432 is located enters the first countersunk groove 251, the loading stud 240 can be effectively prevented from rotating along its axis. The anti-drop post 250 may also be provided with a second countersunk groove (not shown in the figure) that matches the head of the flat-head screw 260, to prevent the head of the flat-head screw 260 from contacting the bent specimen 300 and affecting the deformation of the bent specimen 300.

[0040] According to one aspect of this utility model, a four-point bending test apparatus for preventing jamming and detachment is proposed, comprising a four-point bending test fixture 200 as described above, a frame, a loading device, and a corresponding control device. The four-point bending test fixture 200 clamps the bending specimen 300 and fixes it to the frame. The control device controls the loading device to apply a predetermined pressure to the bending specimen 300 through the loading stud 240. After pressure is applied, the bending specimen 300, together with the fixture 200, is placed in a hydrogen environment to observe delayed cracking.

[0041] The four-point bending fixture of this utility model has a threadless lower end for the loading stud, so that the stress application process can be carried out smoothly without the stud or pressure block getting stuck; and the four-point bending fixture effectively limits the axial displacement of the loading stud by cooperating with the pressure block through the anti-drop post, so that the pressure block will not fall off during the stress unloading process.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A four-point bending test fixture (200) for preventing jamming and detachment, characterized in that, include: The base (210) defines a downwardly opening cavity and is provided with a pair of first support points extending upward toward the cavity; A pressure block (220) is housed in the cavity and has a pair of downwardly extending second support points on its lower surface. The distance between the first support points is greater than the distance between the second support points. A bending specimen (300) is provided between the first support points and the second support points to form a four-point support. Loading stud (240), configured as a finely ground column and extending through the base (210) and the pressure block (220); An anti-detachment post (250) is connected to the loading stud (240) and configured to cooperate with the pressure block (220) to limit the axial displacement of the loading stud (240).

2. The clamp (200) according to claim 1, characterized in that, The base (210) includes: The base body (211) extends laterally and has a first through hole (2111) through the middle. A pair of support portions (213) extend symmetrically downward from both ends of the base body (211) and are in an L-shaped structure opposite to each other; A pair of protrusions (212) extend symmetrically downward from the base body (211), wherein the distance between the pair of protrusions (212) is less than the distance between the pair of support portions (213).

3. The clamp (200) according to claim 2, characterized in that, The base (210) also includes: A pair of fixing holes (2112) are provided for fixing the base (210) to the fixture.

4. The clamp (200) according to claim 2, characterized in that, The clamp (200) further includes a support column (230), wherein, A pair of support portions (213) are respectively provided with a first groove (2131), and the support column (230) is disposed in the first groove (2131) to form the first support point; The bottom of the pressure block (220) is provided with a second groove (222), and the support column (230) is disposed in the second groove (222) to form the second support point.

5. The clamp (200) according to claim 1, characterized in that, The loading stud (240) includes: Loading end (241) is configured to connect to the loading device; The column (242) extends through the base (210); and The connecting end (243) extends through the pressure block (220) and is connected to the anti-falling column (250); The diameter of the column rod (242) is larger than the diameter of the connecting end (243).

6. The clamp (200) according to claim 5, characterized in that, A second through hole (221) is provided through the middle of the pressure block (220), and the second through hole (221) includes: The second through hole has a first aperture that matches the connecting end (243); and The second through hole has two sections, with a second hole diameter that matches the anti-fall-off column (250); Wherein, the first aperture is smaller than the second aperture.

7. The clamp (200) according to claim 6, characterized in that, The clamp (200) includes a flat-head screw (260), wherein the bottom of the connecting end (243) is provided with a threaded hole (2431), the anti-drop post (250) is provided with a third through hole (252), and the flat-head screw (260) passes through the third through hole (252) to connect the anti-drop post (250) to the connecting end (243).

8. The clamp (200) according to claim 7, characterized in that, The connecting end (243) is provided with a radially recessed platform (2432), and the anti-falling column (250) is provided with a first sinkhole (251) that matches the section where the platform (2432) is located.

9. The clamp (200) according to claim 7, characterized in that, The anti-loosening post (250) is provided with a second recess that matches the head of the flat-head screw (260).

10. A four-point bending test device for preventing jamming and detachment, characterized in that, Includes the clamp as described in any one of claims 1-9.

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