Ceramic composite material rivet tensile single shear sample and test method

Abstract

The invention belongs to the technical field of biomedical composite material tests, and provides a ceramic composite material rivet tensile simple shear sample and a test method.The tensile simple shear sample comprises a first connected piece and a second connected piece which are the same in structure and size, and the tensile simple shear sample is of a centrosymmetric cuboid structure; the upper portion of the middle of the first connected piece is cut off to form an upper section of the first connected piece and a lower section of the first connected piece, the lower portion of the middle of the second connected piece is cut off to form an upper section of the second connected piece and a lower section of the second connected piece, the cut-off kerf of the first connected piece and the cut-off kerf of the second connected piece are in central symmetry, and a test assessment area is arranged between the two kerfs. And two clamping loading areas are formed from the two kerfs to the upper and lower end faces of the tensile single shear sample. According to the invention, it can be effectively ensured that the shear surface of the rivet bears a pure shear load in the tensile loading process, and the additional bending moment influence caused by misalignment of the shear surface of the rivet and a loading shaft of a testing machine is completely eliminated from the aspect of sample type.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedical composite material testing, and relates to a ceramic composite material rivet tensile single shear specimen and a testing method. Background Art

[0002] Ceramic composite materials have excellent properties such as low density, high strength, high stiffness, and stable physical and chemical properties. They will greatly reduce the weight of the structure and significantly improve the structural performance when applied in the fields of biomedicine and other fields. Ceramic materials have good biocompatibility, mechanical properties and chemical stability, and are widely used in the field of medical implants, such as orthopedic implants, dental implants, ENT implants, etc., with great performance advantages and development prospects. In orthopedics, dentistry, maxillofacial and other parts, bioceramics need to bear a certain load, and stable and reliable connections are required between bones and joints. At present, the commonly used connection methods for bioceramics are mainly brazing and diffusion welding, but the above methods require the application of greater pressure, resulting in deformation of the structure in the biological implant device, which does not meet the requirements of biological implant devices for dimensional accuracy; and the materials used for welding have physical property mismatch and biocompatibility problems, and it is urgent to develop a medical implant connection method with good physical property matching and biocompatibility.

[0003] The rivet connection of bioceramic materials has the advantages of smooth surface, stable physical and chemical properties, good matching, and the ability to maintain a good appearance. It can be used as an important connection method for bioceramic medical implants. The stress of the connected parts can be effectively reduced by designing the rivet layout, and conducting shear mechanical property tests on rivet connection structures is a key link in assessing and verifying the feasibility of its application.

[0004] The rivet shear performance test is mainly divided into double shear and single shear test methods. Double shear specimens are usually symmetrical structures, and double shear test research can be carried out by compression. However, the rivet in the double shear specimen has two bearing surfaces. The load distribution of the two bearing surfaces is affected by the specimen processing technology and size, and the specimen type size error will introduce additional bending moment, affecting the test and calculation analysis of the rivet shear performance. The stress state of the rivet bearing surface in the single shear specimen is clear, and accurate shear performance can be effectively obtained. In addition, most rivet connections and bearing types in engineering applications are the same as single shear. Therefore, it is necessary to develop single shear specimens and test methods for rivet connection structures.

[0005] Regarding the single shear performance test of rivets, some researchers currently use hole-slot type fixtures to clamp and fix rivets to test the shear performance of rivets. For example, CN112213183A discloses a test fixture for testing the shear bearing capacity of wooden pins in double shear connections of wooden structures, CN206339435U discloses an aluminum alloy rivet wire shear test fixture, and CN107014701A discloses a shear strength test method for ceramic-based composite pins. The above patents conduct shear performance tests on single rivet / pin parts, and do not assemble the rivets / pins with the connected parts for testing. They cannot reflect and reproduce the installation process and constraint conditions of real components in the project, and cannot accurately characterize the shear performance of rivets / pins in engineering applications. Some other researchers installed rivets / pins on special test devices, such as CN115365431A disclosed a rivet shearing device and a rivet shearing method, and CN220399109U disclosed a rivet shearing test tool. On the one hand, these special test devices are not real connected parts, and the installation process and matching state of their pins / rivets are significantly different from the actual engineering. On the other hand, these special test devices do not consider the centering of the loading process, and it is very easy to introduce additional bending moments to the rivets / pins during the test, affecting the test results. After the ceramic composite rivet is assembled to the connected part, it is necessary to fill the rivet hole gap and deposit the matrix (CN112555254A discloses a connection method and rivet structure of ceramic matrix composite materials) to improve the strength and sealing of the rivet connection structure. Therefore, it is necessary to use a processing technology and preparation method consistent with the engineering application to manufacture the rivet connection structure, and cut the rivet sample to carry out mechanical property testing. The test results obtained can effectively evaluate the shear performance of the ceramic rivet connection structure and guide the design and optimization of the rivet connection structure. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention aims to provide a ceramic composite material rivet tensile single shear specimen. By designing the single shear specimen type, the single shear performance of the rivet connection in the actual assembly connection structure can be accurately and effectively obtained.

[0007] The present invention is achieved through the following technical solutions.

[0008] A ceramic composite material rivet tensile single shear specimen, comprising a connected part 1 and a connected part 2 with the same structure and size, the tensile single shear specimen is a centrally symmetrical rectangular parallelepiped structure, after the tensile single shear specimen is rotated 180 degrees around the center point, the rotated tensile single shear specimen can completely overlap with the tensile single shear specimen before the rotation, the middle of the connected part 1 is cut off to form an upper connected part 1 and a lower connected part 1, the middle of the connected part 2 is cut off to form an upper connected part 2 and a lower connected part 2, the cut seam of the connected part 1 is centrally symmetrical with the cut seam of the connected part 2, a test assessment area is between the two cut seams, two clamping loading areas are formed from the two cut seams to the upper and lower end faces of the tensile single shear specimen, the rivet connects the connected part 1 and the connected part 2 in the thickness direction, the rivet is located in the middle of the test assessment area (also the middle of the tensile single shear specimen), and the rivet shear surface is located in the middle of the specimen thickness (i.e., the fitting surface of the connected part 1 and the connected part 2).

[0009] Furthermore, the upper connected member 1 and the lower connected member 2 have the same structure and size, and the lower connected member 1 and the upper connected member 2 have the same structure and size.

[0010] Furthermore, the two clamping loading areas are provided with pins, puncture sutures or adhesive bonding in the thickness direction to enhance the out-of-plane bonding strength.

[0011] Furthermore, the tensile single shear specimen is designed, prepared and processed in an integrated manner, and the preparation process and flow of the rivet connection parts in the tensile single shear specimen are completely consistent with the preparation process and flow of the actual connection parts.

[0012] Furthermore, the tensile single shear specimen is prepared separately or cut from the prepared rivet connector, and then the connected part 1 and the connected part 2 are cut along the boundary line (i.e. the above-mentioned cut) between the test assessment area and the clamping loading area by laser / mechanical processing or the like.

[0013] A testing method for a ceramic composite material rivet tensile single shear specimen, wherein the single shear specimen obtained by the above process is clamped and fixed in a clamping loading area by a testing machine chuck of a testing machine, and a test loading scheme is set to carry out a tensile single shear test on the tensile single shear specimen.

[0014] The tensile single shear specimen is a rectangular parallelepiped, which can make full use of the rivet connection structure and avoid wasting materials when cutting. It can effectively ensure that the rivet shear surface bears pure shear load during tensile loading, and completely eliminate the additional bending moment caused by the misalignment between the rivet shear surface and the loading axis of the testing machine from the specimen type. The number and arrangement of rivets are designed according to the test purpose in the test assessment area, and the clamping loading area adopts pins / puncture sutures / adhesion and other methods in the thickness direction to enhance the out-of-plane bonding strength, which can ensure that during the tensile shear test, the single shear specimen does not experience relative sliding of the connector, effectively ensuring the success rate of the tensile single shear specimen.

[0015] Compared with the prior art, the advantages of the present invention are: the specimen adopts an equal thickness design, and the rivet shear surface is located in the middle of the specimen thickness, which can effectively ensure that the rivet shear surface bears pure shear load during tensile loading, and completely eliminates the additional bending moment caused by the misalignment of the rivet shear surface and the loading axis of the testing machine from the specimen type; the specimen adopts an integrated design, preparation, and processing to effectively ensure that the specimen and the real component have the same preparation process, and the specimen type is a centrally symmetrical rectangular structure, which can make full use of the rivet connector; the specimen is divided into a test assessment area and a clamping loading area. In the test assessment area, the number and arrangement of rivets are designed according to the test purpose. The clamping loading area adopts pins / puncture sutures / adhesion and other methods in the thickness direction to enhance the out-of-plane bonding strength, which can ensure that during the tensile shear test, the single shear specimen does not have relative sliding of the connector, and effectively ensures the success rate of the tensile single shear specimen. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic front view of a single shear specimen of the present invention; Figure 2 It is a side view schematic diagram of a single shear specimen type of the present invention; Figure 3 Schematic diagrams of four arrangements of rivets in the single shear specimen test assessment area of ​​the present invention; Figure 4 It is a schematic diagram of two external bonding strength enhancements of the single shear specimen clamping loading zone surface of the present invention; Figure 5 It is a cross-sectional schematic diagram of a single shear specimen clamping of the present invention; Description of reference numerals: 1. Clamping and loading area; 2. Test and assessment area; 3. Ceramic composite material rivet; 4. Connected part 1; 5. Connected part 2; 6. Pin; 7. Testing machine chuck; 4-1, upper section connected piece 1, 4-2, lower section connected piece 1, 5-1, upper section connected piece 2, 5-2, lower section connected piece 2. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0018] like Figures 1 to 4As shown, a ceramic composite material rivet tensile single shear specimen, the tensile single shear specimen comprises a connected piece 4 and a connected piece 5 with the same structure and size, the tensile single shear specimen is a centrally symmetrical rectangular parallelepiped structure, after the tensile single shear specimen is rotated 180° around the center point, the rotated tensile single shear specimen can completely overlap with the tensile single shear specimen before the rotation, the middle of the connected piece 4 is cut off to form an upper connected piece 4-1 and a lower connected piece 4-2, the middle of the connected piece 2 5 is cut off to form an upper connected piece 2 5-1 and a lower connected piece 2 5-2. Connecting piece 2 5-2, the cut slit of connected piece 1 4 and the cut slit of connected piece 2 5 are symmetrical in center, the test assessment area 2 is between the two cut slits, the two clamping loading areas 1 are from the two cut slits to the upper and lower end faces of the tensile single shear specimen, and the rivet (i.e., the ceramic composite material rivet 3 in the figure) connects connected piece 1 4 and connected piece 2 5 in the thickness direction, the rivet is located in the middle of the test assessment area 2 (also the middle of the tensile single shear specimen), and the rivet shear surface is located in the middle of the specimen thickness (i.e., the fitting surface of connected piece 1 4 and connected piece 2 5).

[0019] Furthermore, the upper connected member 1 4 - 1 and the lower connected member 2 5 - 2 have the same structure and size, and the lower connected member 1 4 - 2 and the upper connected member 2 5 - 1 have the same structure and size.

[0020] Furthermore, the two clamping loading areas 1 are provided with pins 6, puncture sutures or adhesive bonding in the thickness direction to enhance the out-of-plane bonding strength.

[0021] Furthermore, the tensile single shear specimen is designed, prepared and processed in an integrated manner, and the preparation process and flow of the rivet connection parts in the tensile single shear specimen are completely consistent with the preparation process and flow of the actual connection parts.

[0022] Furthermore, the tensile single shear specimen is prepared separately or cut from the prepared rivet connector, and then the connected part 1 4 and the connected part 2 5 are cut along the dividing line (i.e. the above-mentioned cut) between the test assessment area 2 and the clamping loading area 1 by laser / mechanical processing or the like.

[0023] A testing method for a ceramic composite material rivet tensile single shear specimen, wherein the single shear specimen obtained by the above process is clamped and fixed to a clamping loading area 1 by a testing machine chuck 7 of a testing machine, and a test loading scheme is set to carry out a tensile single shear test on the tensile single shear specimen.

[0024] In the present invention, on the one hand, the testing machine clamping method is adopted, which can completely clamp and fix the single shear specimen, avoiding the problem of incomplete contact in the initial stage of the test; on the other hand, a single shear specimen is adopted, and there is only one shear surface in the rivet, which can truly and effectively obtain the strength performance of the shear surface.

[0025] The tensile single shear specimen is a rectangular parallelepiped, which can make full use of the rivet connection structure and avoid wasting materials when cutting. It can effectively ensure that the rivet shear surface bears pure shear load during tensile loading, and completely eliminate the additional bending moment caused by the misalignment between the rivet shear surface and the loading axis of the testing machine from the specimen type. In the test assessment area 2, the number and arrangement of rivets are designed according to the test purpose, and the clamping loading area 1 adopts pins / puncture sutures / adhesion and other methods in the thickness direction to enhance the out-of-plane bonding strength, which can ensure that during the tensile shear test, the single shear specimen does not experience relative sliding of the connector, effectively ensuring the success rate of the tensile single shear specimen.

[0026] In this embodiment, the three-dimensional dimensions of the rivet specimen are: 135 mm in length, 27 mm in width, and 15 mm in thickness, and the diameter of the rivet is 5 mm. The dimensions of the rivet tensile single shear specimen should be determined according to the actual application scenario, and can range from a few millimeters to hundreds of millimeters.

[0027] The present invention can be used in the biomedical industry. In biomedicine, bioceramics are applied to artificial bones, artificial joints, artificial tooth roots, artificial tendons and other parts. The use of the same bioceramic rivets for connection between parts has the advantages of stable physical and chemical properties and good connection matching, and is the best connection technology solution. The application of bioceramics in the above parts requires full and comprehensive experimental research, including mechanical property tests of rivet connection structures, to study the load-bearing capacity of the rivet connection structure and verify the load-bearing reliability of the rivet connection structure.

[0028] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A ceramic composite material rivet tensile single shear specimen, characterized in that: The tensile single shear specimen comprises a connected part 1 (4) and a connected part 2 (5) of the same structure and size. The tensile single shear specimen is a centrally symmetrical rectangular parallelepiped structure. After the tensile single shear specimen is rotated 180 degrees around the center point, the rotated tensile single shear specimen can completely overlap with the tensile single shear specimen before the rotation. The middle of the connected part 1 (4) is cut to form an upper section of the connected part 1 (4-1) and a lower section of the connected part 1 (4-2). The middle of the connected part 2 (5) is cut to form an upper section of the connected part 2 (5-1) and a lower section of the connected part 2 (5-2). The cut slit of the connected part 1 (4) is centrally symmetrical with the cut slit of the connected part 2 (5). The test assessment area (2) is between the two cut slits. The two clamping loading areas (1) are formed from the two cut slits to the upper and lower end surfaces of the tensile single shear specimen. The rivet connects the connected part 1 (4) and the connected part 2 (5) in the thickness direction. The rivet is located in the middle of the test assessment area (2). The shear surface of the rivet is located in the middle of the specimen thickness.

2. A ceramic composite material rivet tensile single shear specimen according to claim 1, characterized in that: The upper connected member 1 (4-1) and the lower connected member 2 (5-2) have the same structure and size, and the lower connected member 1 (4-2) and the upper connected member 2 (5-1) have the same structure and size.

3. The ceramic composite material rivet tensile single shear specimen according to claim 1, characterized in that: The two clamping loading areas (1) are pinned, pierced, sutured or glued in the thickness direction to enhance the out-of-plane bonding strength.

4. The ceramic composite material rivet tensile single shear specimen according to claim 1, characterized in that: The tensile single shear specimen is prepared separately or cut from the prepared rivet connection part, and then the connected part 1 (4) and the connected part 2 (5) are cut along the boundary line between the test assessment area (2) and the clamping loading area (1) by laser / mechanical processing.

5. A test method for tensile single shear specimens of ceramic composite rivets, characterized in that: The ceramic composite material rivet tensile single shear specimen according to any one of claims 1 to 4 is clamped and fixed in the clamping loading area (1) by a testing machine chuck (7) of a testing machine, and a test loading scheme is set to carry out a tensile single shear test on the tensile single shear specimen.

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