System and method for testing shear strength of composite board

Abstract

The invention discloses a composite board shearing strength testing system and method, the system comprises a tool and a composite board, the tool is used for limiting the composite board, the composite board comprises a sheared boss and a shearing back board, the shearing strength of the sheared boss is greater than that of the shearing back board, the shearing back board is used for receiving external force until the composite board fails, and the tool is used for limiting the composite board. A groove matched with the lug boss to be sheared is formed in the tool; the method comprises the following steps: manufacturing a sample: taking a base material layer of a composite plate as a sheared boss, and taking a composite material layer as a shearing back plate; a groove matched with the sheared boss is formed in the tool; placing the sample into the tool, placing the sheared boss in the groove, applying an external force to the shearing back plate, recording the external force of the failure of the composite plate, and calculating to obtain the shearing strength; the method can ensure that other plate layers do not fail in advance before the bonding layer fails, and ensures the accuracy of a test result.

Description

Technical Field

[0001] The invention relates to the field of composite plate mechanical testing, and in particular to a composite plate shear strength testing system and method. Background Art

[0002] The interface of the composite plate is a surface. During the shear test, the top angle of the shear fixture may not hit the interface exactly, and force may not be applied at the interface. At the interface, the base material will be sheared inward, and the composite material will be sheared outward. The shear test requires that the value measured when neither the base material nor the composite material fails is the shear strength of the interface. For the shear strength test of the composite plate, please refer to the 6th shear test of GB / T6396-2008 "Test Methods for Mechanical and Process Properties of Composite Steel Plates": 6.2.2 The sample size should meet Figure 1 If the joint surface is corrugated, after the composite material is processed, the joint surface should be a spot of two metals mixed; according to the requirements of Table 1 in the document, a b The base plate is the substrate, and the exposed sheared boss is the composite plate.

[0003] In the shear specimen mentioned in 6.2.2 of GB / T 6396-2008 "Test Methods for Mechanical and Process Properties of Composite Steel Plates", a c For composite materials, when the shear strength of the composite material is less than the shear strength of the interface, the composite material will fail during shearing, and the measured value is the shear strength of the composite material, which is less than the shear strength of the interface. Therefore, according to the shear test in Article 6 of GB / T 6396-2008 "Test Methods for Mechanical and Process Properties of Composite Steel Plates", during the shear strength test of the composite plate, due to the low strength of the composite material, the composite material failed prematurely before the interface strength was measured, resulting in test data errors. Summary of the invention

[0004] The purpose of the invention is to provide a composite plate shear strength testing system and method, which solves the problem that the prior art cannot accurately test the shear strength of the composite plate.

[0005] The present invention is implemented as follows: a composite plate shear strength testing system includes a tooling and a composite plate, wherein the tooling is used to limit the composite plate, the composite plate includes a sheared boss and a shear back plate, the shear strength of the sheared boss is greater than that of the shear back plate, the shear back plate is used to receive external force until the composite plate fails, and the tooling is provided with a groove that cooperates with the sheared boss.

[0006] When the shear strength of the composite plate is tested according to the method of the national standard, the test system uses static compression force or static tension force, and through the corresponding test device, the bonding surface of the substrate and the composite material parallel to the direction of the test force is subjected to shear force until separation, so as to determine its shear strength; the method in the national standard is that the composite material is prone to premature failure, resulting in inaccurate test data; in the present invention, a layer of the composite plate with high shear strength is used as the sheared boss, and a groove that cooperates with the sheared boss is opened on the tooling, and the shear back plate receives external force. The shearing process is mainly the process of applying force to the sheared boss. The layer of the composite plate with high shear strength is used as the sheared boss, which improves the shear strength of the sheared boss and avoids the situation of premature failure of the sheared boss. At the same time, the sheared boss is stuck in the groove. Under the limitation of the tooling groove, it can prevent the sheared boss from twisting and other deformation movement during the shearing process, so that the composite plate shear strength test system recorded in the present invention can ensure that other board layers will not fail prematurely before the bonding layer fails, thereby ensuring the accuracy of the test results.

[0007] A further technical solution of the present invention is: a surface reduction groove is provided on the shear back plate, and the surface reduction groove is placed on the side of the sheared boss.

[0008] The surface reduction groove is on the shear back plate and is placed on the side of the sheared boss. Since the shear strength of the sheared boss is greater than that of the shear back plate, during the shearing process, the sheared boss is subjected to the force of the top angle of the tooling, which will cause a certain degree of torsion, thereby causing part of the sheared boss to be embedded in the back plate, making the shearing process higher. The present invention discovered the above situation during the experiment. In order to further ensure the accuracy of the experiment, when the sheared boss is twisted, the surface reduction groove will not be embedded in the shear back plate, but twisted into the surface reduction groove, thereby avoiding inaccurate shear strength test caused by embedding in the shear back plate.

[0009] A further technical solution of the present invention is that the depth of the surface reduction groove is 0.5-1 mm.

[0010] A further technical solution of the present invention is that the groove is a strip-shaped through groove.

[0011] The strip-shaped through groove can be used for composite panels of different lengths, is easy to install, and reduces material usage.

[0012] A further technical solution of the present invention is that the end of the composite plate extends out of the tooling.

[0013] The end of the composite board extends out of the tooling, and external force is applied to the composite board, making it more convenient to perform shear strength test.

[0014] The present invention also provides a composite plate shear strength testing method, comprising the following steps:

[0015] Step 1: Make samples: Use the base material layer of the composite board as the sheared boss and the composite material layer as the shear backing plate;

[0016] Step 2: Making tooling: The tooling is provided with a groove matching the boss to be sheared;

[0017] Step 3: Place the sample into the fixture, place the sheared boss into the groove, apply external force to the shear back plate, record the external force that causes the composite plate to fail, and calculate the shear strength.

[0018] A further technical solution of the present invention is: the testing method is performed based on the testing system.

[0019] Beneficial effects of the present invention: In the present invention, a layer of the composite plate with high shear strength is used as the sheared boss, and a groove matching the sheared boss is opened on the tooling, and the shear back plate receives external force. The shearing process is mainly the process of applying force to the sheared boss. The layer of the composite plate with high shear strength is used as the sheared boss, which improves the shear strength of the sheared boss and avoids the premature failure of the sheared boss. At the same time, the sheared boss is stuck in the groove, and under the limitation of the tooling groove, it can prevent the sheared boss from twisting and other deformation movements during the shearing process, so that the composite plate shear strength test system recorded in the present invention can ensure that other board layers will not fail prematurely before the bonding layer fails, thereby ensuring the accuracy of the test results.

[0020] The surface reduction groove is on the shear back plate and is placed on the side of the sheared boss. Since the shear strength of the sheared boss is greater than that of the shear back plate, during the shearing process, the sheared boss is subjected to the force of the top angle of the tooling, which will cause a certain degree of torsion, thereby causing part of the sheared boss to be embedded in the back plate, making the shearing process higher. The present invention discovered the above situation during the experiment. In order to further ensure the accuracy of the experiment, when the sheared boss is twisted, the surface reduction groove will not be embedded in the shear back plate, but twisted into the surface reduction groove, thereby avoiding inaccurate shear strength test caused by embedding in the shear back plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the background technology provided by the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of the composite plate provided by the present invention;

[0023] Figure 3 It is a structural schematic diagram of the tooling provided by the present invention;

[0024] Figure 4 It is a structural schematic diagram of the tooling provided by the present invention;

[0025] Figure 5It is a structural schematic diagram of a composite plate shear strength testing system provided by the present invention;

[0026] Figure 6 The present invention provides a flow chart of a composite plate shear strength testing method.

[0027] Figure numerals: 1. tooling, 2. composite plate, 21. sheared boss, 22. shearing back plate, 23. surface reduction groove, 11. groove, 12. first fixture, 13. second fixture. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0029] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0030] Embodiment 1:

[0031] Figure 2-5 A composite plate shear strength testing system is shown, including a tool 1 and a composite plate 2, wherein the tool 1 is used to limit the composite plate 2, the composite plate 2 includes a sheared boss 21 and a shear back plate 22, the shear strength of the sheared boss 21 is greater than that of the shear back plate 22, the shear back plate 22 is used to receive external force until the composite plate fails, and the tool 1 is provided with a groove 11 that cooperates with the sheared boss 21.

[0032] When the shear strength of the composite plate is tested according to the method of the national standard, the test system uses static compression force or static tension force, and through the corresponding test device, the bonding surface of the substrate and the composite material parallel to the direction of the test force is subjected to shear force until separation, so as to determine its shear strength; the method in the national standard is that the composite material is prone to premature failure, resulting in inaccurate test data; in the present invention, a layer of the composite plate with high shear strength is used as the sheared boss, and a groove that cooperates with the sheared boss is opened on the tooling, and the shear back plate receives external force. The shearing process is mainly the process of applying force to the sheared boss. The layer of the composite plate with high shear strength is used as the sheared boss, which improves the shear strength of the sheared boss and avoids the situation of premature failure of the sheared boss. At the same time, the sheared boss is stuck in the groove. Under the limitation of the tooling groove, it can prevent the sheared boss from twisting and other deformation movement during the shearing process, so that the composite plate shear strength test system recorded in the present invention can ensure that other board layers will not fail prematurely before the bonding layer fails, thereby ensuring the accuracy of the test results.

[0033] In this embodiment, the composite board includes a composite material layer, a substrate layer, and a bonding layer disposed between the composite material layer and the substrate layer.

[0034] In this embodiment, the shear strength of the base material layer of the composite plate is higher than that of the composite material layer, and therefore, the base material layer is used as the sheared boss.

[0035] In this embodiment, a surface reduction groove 23 is provided on the shear back plate 22 , and the surface reduction groove 23 is located on the side of the sheared boss 21 .

[0036] The surface reduction groove is on the shear back plate and is placed on the side of the sheared boss. Since the shear strength of the sheared boss is greater than that of the shear back plate, during the shearing process, the sheared boss is subjected to the force of the top angle of the tooling, which will cause a certain degree of torsion, thereby causing part of the sheared boss to be embedded in the back plate, making the shearing process higher. The present invention discovered the above situation during the experiment. In order to further ensure the accuracy of the experiment, when the sheared boss is twisted, the surface reduction groove will not be embedded in the shear back plate, but twisted into the surface reduction groove, thereby avoiding inaccurate shear strength test caused by embedding in the shear back plate.

[0037] In this embodiment, the depth of the surface reduction groove 23 is 0.5-1 mm.

[0038] In this embodiment, the thickness of the substrate layer is 9 mm, the thickness of the substrate layer is 2 mm, the depth of the surface reduction groove is 0.5-1 mm, and the width is 4 mm.

[0039] In this embodiment, the groove 11 is a strip-shaped through groove.

[0040] The strip-shaped through groove can be used for composite panels of different lengths, is easy to install, and reduces material usage.

[0041] In this embodiment, the end of the composite plate 2 extends out of the tooling 1 .

[0042] The end of the composite board extends out of the tooling, and external force is applied to the composite board, making it more convenient to perform shear strength test.

[0043] In this embodiment, the shear back plate extends out of the tooling to receive external force.

[0044] In this embodiment, the tooling includes a first clamp 12 and a second clamp 13, and the first clamp 12 and the second clamp 13 are used to install the composite plate, wherein the first clamp 12 is provided with a groove that matches the sheared boss on the composite plate.

[0045] In this embodiment, a positioning hole is provided on the tooling, the composite plate is placed between the first clamp 12 and the second clamp 13, and the tooling is fixed by passing a positioning bolt through the positioning hole.

[0046] Embodiment 2:

[0047] like Figure 2-6 A composite plate shear strength test method is shown, comprising the following steps:

[0048] Step 1, making a sample: using the base material layer of the composite board 2 as the sheared boss 21, and the composite material layer as the shear back plate 22;

[0049] Step 2: Making the tool 1: The tool 1 is provided with a groove 11 that matches the sheared boss 21;

[0050] Step 3: Place the sample into the tooling 1, place the sheared boss 21 into the groove 11, apply external force to the shear back plate 22, record the external force that causes the composite plate 2 to fail, and calculate the shear strength.

[0051] In this embodiment, the sample is cut under the shear load F, and the cross-sectional area of ​​the sample is S. The shear strength τ can be obtained b =F / S.

[0052] In this embodiment, the testing method is performed based on the testing system described in the first embodiment.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite plate shear strength testing system, comprising a tool (1) and a composite plate (2), wherein the tool (1) is used to limit the position of the composite plate (2), and is characterized in that: The composite plate (2) comprises a sheared boss (21) and a shear back plate (22); the shearing strength of the sheared boss (21) is greater than that of the shear back plate (22); the shear back plate (22) is used to receive external force until the composite plate fails; and the tooling (1) is provided with a groove (11) that cooperates with the sheared boss (21).

2. A composite plate shear strength testing system according to claim 1, characterized in that: The shear back plate (22) is provided with a surface reduction groove (23), and the surface reduction groove (23) is arranged on the side of the sheared boss (21).

3. A composite plate shear strength testing system according to claim 2, characterized in that: The depth of the surface reduction groove (23) is 0.5-1 mm.

4. A composite plate shear strength testing system according to claim 1, characterized in that: The groove (11) is a strip-shaped through groove.

5. A composite plate shear strength testing system according to claim 1, characterized in that: The end of the composite plate (2) extends out of the tooling (1).

6. A composite plate shear strength test method, characterized in that: The following steps are involved: Step 1, making a sample: using the base material layer of the composite board (2) as the sheared boss (21), and the composite material layer as the shearing back plate (22); Step 2: manufacturing a tool (1): the tool (1) is provided with a groove (11) that matches the sheared boss (21); Step 3: Place the sample into the tooling (1), place the sheared boss (21) into the groove (11), apply external force to the shear back plate (22), record the external force that causes the composite plate (2) to fail, and calculate the shear strength.

7. A composite plate shear strength testing method according to claim 6, characterized in that: The testing method is performed based on the testing system described in any one of claims 1 to 5.

Images