Welding shear test device and method for lattice cells and strips of annular fuel assembly grillwork

Abstract

The invention particularly relates to an annular fuel assembly grillwork lattice cell and strip welding shear test device and method, and belongs to the technical field of grillwork shear tests. The welding shear test device for the grillage lattice cell and the strip of the annular fuel assembly comprises a clamping device used for supporting and placing the grillage lattice cell and clamping and placing the grillage strip; and the supporting sleeve is used for being inserted into the grillwork lattice cell from the upper part of the grillwork lattice cell so as to support the grillwork lattice cell and bear the pressure applied by the shear testing machine. According to the annular fuel assembly grillwork lattice cell and strip welding shear test method, the annular fuel assembly grillwork lattice cell and strip welding shear test device is used for carrying out an annular fuel assembly grillwork lattice cell and strip welding shear test. The method is simple and convenient to operate, accurate in result and high in repeatability.

Description

Technical Field

[0001] This invention relates to the field of grid shear testing technology, and in particular to a shear testing device and method for welding grid elements and strips of annular fuel assembly. Background Technology

[0002] Shear testing is a fundamental method in the testing of material mechanical properties. Its principle involves applying a pair of equal, opposite, and closely spaced resultant forces to the two sides of a shear specimen, causing the specimen to shift along a shear plane parallel to the line of action of the resultant forces. During the shear test, the maximum stress the specimen withstands when compressed to failure is called its compressive strength. This strength is typically determined by the compressive force-deformation curve or by directly reading the maximum compressive force from the force gauge of the shear testing machine, and then calculated using appropriate formulas.

[0003] In the field of welding, the shear force test, also known as the compression shear test, is widely used to evaluate the connection strength of weld joints. Currently, a common testing method involves applying a pair of equal and opposite forces between the weld tongue and the guide tube that make up the weld joint until the weld joint detaches or the weld tongue breaks. The maximum applied force recorded at this point is the maximum shear force of the weld joint.

[0004] The shear test specimen for the annular fuel assembly grid is formed by spot welding the grid elements and grid strips together. During the shear test, the grid strips need to be fixed, and then an external force is applied to the grid elements using a shear testing machine to separate them from the grid strips under the action of shear force, in order to determine their weld strength.

[0005] However, existing testing methods have certain limitations. First, because the grid cells and grid strips are completely bonded together after spot welding, forming a unique integral structure, the sidewalls of the grid cells lack effective clamping space and stress points. Traditional test fixtures cannot stably and reliably clamp the specimen, making the test difficult to conduct.

[0006] Secondly, due to the thin wall thickness of the grid elements, their structural rigidity is insufficient. When the test force is directly applied, the grid element wall is prone to crushing or plastic deformation at the stress point, rather than pure shear failure at the weld joint. This premature failure mode makes it impossible to measure the true weld joint strength, resulting in test failure.

[0007] Finally, the very close height of the grid cells to the adjacent strips means that the testing machine's pressure plate does not have sufficient operating space or a clearly defined stress point to apply force to the grid cells individually. This structural characteristic makes conventional compression-shear testing methods unsuitable for this type of specimen.

[0008] Currently, there is a lack of a shear testing device and method specifically for the special structure of annular fuel assembly grids. The aforementioned problem severely restricts the accurate assessment of its welding quality and process optimization. Summary of the Invention

[0009] One of the objectives of this invention is to solve the problem that grid cells and grid strips cannot be stably clamped and fixed due to their complete fit and special shape. This invention provides a welding shear test device and method for annular fuel assembly grid cells and strips to achieve stable clamping and fixing of the annular fuel assembly grid cells and strips.

[0010] The second objective of this invention is to solve the problem that the thin wall thickness of the grid cells easily leads to deformation and crushing during the application of force, resulting in test failure. This invention provides a shear test device and method for welding grid cells and strips of annular fuel assembly, ensuring that external force can be effectively transmitted to the weld joint, causing shear failure.

[0011] The third objective of this invention is to solve the problem that the test machine pressure plate has no effective force-bearing point and cannot carry out the test because the grid cells and strips are at similar heights. The invention provides a welding shear test device and method for annular fuel assembly grid cells and strips, which can achieve precise force application to the grid cells.

[0012] To achieve the above objectives, the present invention aims to provide a simple, accurate, and highly repeatable device and method for shear testing of annular fuel assembly grid elements and strips.

[0013] To achieve the above objectives, the present invention provides the following technical solution:

[0014] A shear test apparatus for welding grid elements and strips of annular fuel assembly includes:

[0015] Clamping device, used to support and place grid cells and clamp and place grid strips;

[0016] Support sleeves are used to insert grid cells from above to support them and to withstand the pressure applied by the shear testing machine.

[0017] As one possible implementation, the clamping device includes a clamping base, a strip clamping area, a cell placement area, and a support device;

[0018] The clamping base is a hollow cylindrical structure; the lower half of the clamping base is the cell placement area, used to place grid cells;

[0019] The upper half of the clamping base is cut off at a certain height from the middle of the cylinder height along the diameter direction, forming an open structure called the strip clamping area; inside the strip clamping area, there is a transverse through groove along the direction of its inner diameter tangent for clamping and placing the grid strip.

[0020] The support device is installed at the top center of the right side of the cell placement area to provide lateral support for the grid cells located in the cell placement area.

[0021] One possible implementation involves a clamping base with a height of 70mm to 75mm and an outer diameter of Φ42mm to Φ45mm, made of 1Cr18Ni9Ti stainless steel.

[0022] As one possible approach, the height of the cell placement area is 38mm to 40mm, and the inner diameter is Φ26mm to Φ28mm.

[0023] As one possible approach, half of the cylinder is cut off from the upper half of the clamping base along the diameter direction of the cylinder, 30mm to 35mm below the middle of the cylinder height, forming an open structure called the strip clamping area.

[0024] As one possible approach, the inner wall of the strip clamping area has a tapered cross-section, which tapers uniformly from its bottom end to its top end.

[0025] As one possible approach, the transition contraction angle of the conical surface is 7°.

[0026] As one possible approach, the width of the transverse through-slot is 1.0mm to 1.2mm, and the depth is 15mm to 16mm.

[0027] As one possible approach, a threaded hole is provided at the top center of the right side of the cell placement area for mounting a support device;

[0028] The support device includes a threaded rod and a support plate that is laterally rotatably connected to the top of the threaded rod. The bottom of the threaded rod is threadedly connected to a threaded hole at the center of the top right side of the cell placement area.

[0029] By rotating the support plate to make it contact the side of the grid cell and providing lateral support force to the side of the grid cell, the grid cell is kept in a vertical state.

[0030] One possible approach is to use a threaded hole depth of 10mm to 12mm.

[0031] As one possible implementation method, the support sleeve includes:

[0032] The grid filling end is used to insert the grid cell from above to support the grid cell;

[0033] The grid compression end, connected to the grid filling end, is used to withstand the pressure applied by the shear testing machine.

[0034] As one possible approach, the grid filling end has a cross structure with a height of 27mm to 29mm and an overall width of 15.5mm to 15.6mm; the cross section of the grid filling end has a cross structure with a cross width of 7.02mm to 7.08mm and a cross depth of 4.3mm to 4.4mm.

[0035] As one possible implementation method, the compression end of the grid is a tubular structure with a height of 40mm to 45mm, an outer diameter of Φ16mm to Φ16.5mm, and an inner diameter of Φ13mm to Φ13.5mm.

[0036] On the other hand, the present invention also provides a method for shear testing of annular fuel assembly grid elements and strips welded together, using the above-mentioned shear testing apparatus for annular fuel assembly grid elements and strips welded together, comprising the following steps:

[0037] The grid cells are supported and placed using a clamping device, and the grid strips are clamped and placed.

[0038] Insert the support sleeve into the grid cell from above to support the grid cell;

[0039] The shear testing machine applies pressure to the support sleeve to conduct a shear test. After the pressure is applied but before the shear force reaches its maximum value, the clamping device removes the lateral support of the grid element.

[0040] As one feasible approach, the shear test method for welding ring fuel assembly grid cells and strips includes the following steps:

[0041] Step 1: Insert the grid strip on one side of the sheared sample into the transverse through groove of the strip clamping area;

[0042] Step 2: Adjust the support plates of the support device to provide lateral support for the grid elements, so that the grid elements are in a vertical state.

[0043] Step 3: Insert the grid filling end of the support sleeve into the grid cell from above to complete the assembly of the shear test device;

[0044] Step 4: Place the assembled shear test device on the compression platform of the shear test machine and apply pressure to the grid compression end of the support sleeve to conduct a shear test.

[0045] After pressure is applied but before the shear force reaches its maximum value, the lateral support of the support plate of the support device on the grid cell is removed.

[0046] Beneficial technical effects of the present invention:

[0047] The present invention provides a shear testing device and method for welding shear elements and strips of annular fuel assembly, achieving stable and non-destructive fixation of shear specimens with special shapes. By designing a hollow cylindrical clamp with a tapered transition in the middle, the open structure in the middle ensures that the grid elements are in a free state, avoiding improper constraint. Simultaneously, a transverse slit through-slot opened along the tangent of the inner diameter in the reserved portion can accurately accommodate and clamp the strip on the other side. This design cleverly adapts to the special shape of the grid elements and grid strips being completely fitted together. While effectively fixing the grid strips, it ensures that the grid elements can smoothly pass through the hollow part of the clamping device without contacting the inner wall, thus creating conditions for subsequent force application and fundamentally solving the technical problem of being unable to clamp due to the special shape of the shear specimen.

[0048] The annular fuel assembly grid cell and strip welding shear test apparatus and method of the present invention effectively prevent stress deformation of thin-walled grid cells and ensure the effectiveness of the shear test. By employing a support sleeve structure, which is inserted into the grid cell before the shear test, internal support is provided. When the shear testing machine applies force through this support sleeve, the force is indirectly and uniformly transmitted to the weld area through the sleeve, rather than acting directly on the thin-walled grid cell. This indirect force-bearing method greatly enhances the local stiffness and instability resistance of the grid cell, effectively preventing crushing or plastic deformation during the shear test, thereby ensuring that the shear specimen ultimately fails in the form of weld shear, significantly improving the success rate and reliability of the shear test results.

[0049] The annular fuel assembly grid cell and strip welding shear test apparatus and method of the present invention ensures precise alignment at the initial stage of the test and accuracy of the results. A side support mechanism consisting of a threaded rod and a laterally rotatable support plate provides fine-tuning lateral support to the grid cells before the test begins. By adjusting the position of the support plate, the grid cells are precisely vertical before being subjected to force, achieving good initial alignment. This measure effectively avoids non-pure shear effects such as eccentric loading and bending moment caused by the tilting of the shear specimen, ensuring that the shear test force is accurately transmitted along the predetermined direction, thereby guaranteeing the accuracy of the shear force data and the repeatability of the test results. Attached Figure Description

[0050] Figure 1 A schematic diagram of a shear specimen for welding grid elements and grid strips of an annular fuel assembly;

[0051] Figure 2 A schematic diagram of one embodiment of the clamping device;

[0052] Figure 3 A schematic diagram of one embodiment of the support sleeve;

[0053] Figure 4 A top view of one embodiment of the support sleeve;

[0054] Figure 5 This is an assembly diagram of an embodiment of a shear test apparatus for welding grid elements and strips of an annular fuel assembly.

[0055] In the diagram, 1. Grid cell; 2. Grid strip; 3. Solder joint; 4. Support device; 5. Grid cell placement area; 6. Strip clamping area; 7. Clamping base; 8. Grid filling end; 9. Grid compression end; Detailed Implementation

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0057] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0058] In the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0059] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of description and simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0060] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0061] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments.

[0062] like Figure 1 As shown, the shear test specimen for welding the grid cells and grid strips of the annular fuel assembly is formed by spot welding the grid cells and grid strips together.

[0063] This embodiment provides a shear testing device for welding grid elements and strips of annular fuel assembly, including:

[0064] Clamping device, used to support and place grid cells and clamp and place grid strips;

[0065] Support sleeves are used to insert grid cells from above to support them and to withstand the pressure applied by the shear testing machine.

[0066] like Figure 2 As shown, in this embodiment, the clamping device includes a support device 4, a cell placement area 5, a strip clamping area 6, and a clamping base 7.

[0067] like Figure 2 As shown, in this embodiment, the clamping base 7 is the basic component of the entire device. It is a hollow cylindrical structure with a height of 70mm to 75mm and an outer diameter of Φ42mm to Φ45mm. It is made of 1Cr18Ni9Ti stainless steel to ensure that it has sufficient strength and corrosion resistance.

[0068] like Figure 2 As shown, in this embodiment, the lower half of the clamping base 7 is the grid cell placement area 5, which is used to place grid cells; the height of the grid cell placement area 5 is 38mm to 40mm, and the inner diameter is Φ26mm to Φ28mm.

[0069] like Figure 2 As shown, in this embodiment, half of the upper part of the clamping base 7 is cut off from the middle position of the cylinder height by 30mm to 35mm along the diameter direction of the cylinder, forming an open structure called the strip clamping area 6; the strip clamping area 6 is used to ensure that the grid strip can pass through smoothly.

[0070] Inside the strip clamping area 6, a transverse through groove with a width of 1.0mm to 1.2mm and a depth of 15mm to 16mm is provided along the direction of its inner diameter tangent. This transverse through groove is used for clamping and placing the grid strip.

[0071] The height of the strip clamping area 6 is 30-35mm, and it transitions evenly upwards to a tapered section at a 7° angle. This tapered design ensures that the grid cells pass through smoothly without contacting the inner wall of the clamping base 7.

[0072] like Figure 2 As shown, in this embodiment, an M5 threaded hole with a depth of 10mm to 12mm is provided at the top center of the right side of the cell placement area 5 for installing the support device 4.

[0073] Support device 4 includes a threaded rod and a support plate that is laterally rotatably connected to the top of the threaded rod. The bottom of the threaded rod is threadedly connected to a threaded hole at the center of the top right side of the cell placement area 5.

[0074] By rotating the support plate to make it contact the side of the grid cell and providing lateral support force to the side of the grid cell, the grid cell is kept in a vertical state.

[0075] like Figure 3 and Figure 4 As shown, in this embodiment, the support sleeve is used in conjunction with the clamping device; the support sleeve is made of 1Cr18Ni9Ti stainless steel and includes a grid filling end 8 and a grid compression end 9.

[0076] The grid filling end 8 is used to insert the grid element from above to support it. The grid filling end 8 has a cross structure with a height of 27mm to 29mm, an overall width of 15.5mm to 15.6mm, a cross-shaped cross section with a cross width of 7.02mm to 7.08mm, and a cross depth of 4.3mm to 4.4mm. The cross structure of the grid filling end 8 can fit tightly with the grid element, achieving effective support and protection for the grid element.

[0077] The grid compression end 9 is a tubular structure used to withstand the pressure applied by the shear testing machine. The height of the grid compression end 9 is 40mm to 45mm, the outer diameter is Φ16mm to Φ16.5mm, and the inner diameter is Φ13mm to Φ13.5mm, which provides sufficient strength to withstand the pressure applied by the shear testing machine.

[0078] See Figure 5 This embodiment also provides a method for shear testing of the welded elements and strips of an annular fuel assembly grid, using the aforementioned shear testing apparatus for the welded elements and strips of an annular fuel assembly, comprising the following steps:

[0079] Step 1: Shearing and clamping the sample

[0080] The grid strip on one side of the sheared specimen, which is welded to the grid cell of the annular fuel assembly, is inserted into the transverse through groove of the strip clamping area 6 of the clamping base 7 to fix it firmly. At this time, the grid cell of the sheared specimen is in a free suspended state in the open area of ​​the clamping base 7.

[0081] Step 2: Initial Centering

[0082] The support plate of the rotating support device 4 is brought into contact with the side of the grid cell and provides lateral support force to the side of the grid cell, keeping the grid cell in a vertical state and ensuring accurate initial alignment during the shear test.

[0083] Step 3: Install the support sleeve

[0084] Inserting the grid filling end 8 of the support sleeve into the grid cell from above the grid cell serves two purposes. First, the grid filling end 8 provides further internal support and height to the grid cell, preventing it from deforming under pressure. Second, the top of the grid compression end 9 of the support sleeve provides a clear and reliable stress point for the pressure plate of the shear testing machine.

[0085] Step 4: Perform a shear test

[0086] Place the shear test device with the assembled shear specimen stably on the compression platform of the shear test machine; start the shear test machine, so that the pressure plate of the shear test machine moves downward and contacts the top of the grid compression end 9 of the support sleeve and applies pressure; after the pressure is stabilized and before the shear force reaches its maximum value, rotate the support plate of the support device 4 in the opposite direction and remove the side support of the grid cell, so that it separates from the grid strip under the action of pure shear force.

[0087] Step 5: Post-shear test processing

[0088] After the test, record the maximum shear force value of the shear specimen; then, remove the shear testing device from the shear testing machine, remove the support sleeve and shear specimen from the shear testing device, and clean the shear testing device for future use.

[0089] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A shear test apparatus for welding grid elements and strips of annular fuel assembly, characterized in that, include: Clamping device, used to support and place grid cells and clamp and place grid strips; Support sleeves are used to insert grid cells from above to support them and to withstand the pressure applied by the shear testing machine.

2. The annular fuel assembly grid cell and strip welding shear test apparatus according to claim 1, characterized in that, The clamping device includes a clamping base (7), a strip clamping area (6), a cell placement area (5), and a support device (4); The clamping base (7) is a hollow cylindrical structure; the lower half of the clamping base (7) is the grid cell placement area (5), which is used to place grid cells; The upper half of the clamping base (7) is cut off along the diameter of the cylinder, forming an open structure called the strip clamping area (6); inside the strip clamping area (6), a transverse through groove is provided along the direction of its inner diameter tangent for clamping and placing the grid strip. The support device (4) is installed at the top center of the right side of the cell placement area (5) to provide lateral support for the grid cells located in the cell placement area (5).

3. The annular fuel assembly grid cell and strip welding shear test apparatus according to claim 2, characterized in that, The upper half of the clamping base (7) is cut off at a certain height from the middle of the cylinder height along the diameter direction of the cylinder, forming an open structure called the strip clamping area (6).

4. The annular fuel assembly grid cell and strip welding shear test apparatus according to claim 2, characterized in that, The inner wall of the strip clamping area (6) is a tapered section, which is uniformly tapered from its bottom end to its top end.

5. The annular fuel assembly grid cell and strip welding shear test apparatus according to claim 2, characterized in that, A threaded hole is provided at the top center of the right side of the cell placement area (5) for installing a support device (4); the support device (4) includes a threaded rod and a support plate that is laterally rotatably connected to the top of the threaded rod, and the bottom end of the threaded rod is threadedly connected to the threaded hole at the top center of the right side of the cell placement area (5); by rotating the support plate, it contacts the side of the grid cell and provides lateral support force to the side of the grid cell, so that the grid cell remains vertical.

6. The annular fuel assembly grid cell and strip welding shear test apparatus according to claim 1, characterized in that, The support sleeve includes: The grid filling end (8) is used to insert the grid cell from above the grid cell to support the grid cell; The grid compression end (9) is connected to the grid filling end (8) and is used to withstand the pressure applied by the shear testing machine.

7. The annular fuel assembly grid cell and strip welding shear test apparatus according to claim 6, characterized in that, The grid filling end (8) has a cross structure.

8. The annular fuel assembly grid cell and strip welding shear test apparatus according to claim 6, characterized in that, The grid compression end (9) is a tubular structure.

9. A method for shear testing of welded grid elements and strips in annular fuel assembly, characterized in that, Using the annular fuel assembly grid cell and strip welding shear test apparatus according to any one of claims 1-8, the following steps are included: The grid cells are supported and placed using a clamping device, and the grid strips are clamped and placed. Insert the support sleeve into the grid cell from above to support the grid cell; The shear testing machine applies pressure to the support sleeve to conduct a shear test. After the pressure is applied but before the shear force reaches its maximum value, the clamping device removes the lateral support of the grid element.

10. The method for shear testing of annular fuel assembly grid elements and strips according to claim 9, characterized in that, Includes the following steps: Step 1: Insert the grid strip on one side of the sheared sample into the transverse through groove of the strip clamping area (6); Step 2: Adjust the support plate of the support device (4) to provide lateral support for the grid element and make the grid element vertical. Step 3: Insert the grid filling end (8) of the support sleeve into the grid cell from above to complete the assembly of the shear test device; Step 4: Place the assembled shear test device on the compression platform of the shear test machine and apply pressure to the grid compression end (9) of the support sleeve to carry out the shear test; After pressure is applied and before the shear force reaches its maximum value, the lateral support of the support plate of the support device (4) on the grid cell is removed.

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