Acupuncture method for plate-shaped prefabricated body

Abstract

The invention provides a needling method of a plate-shaped preform, which comprises the following steps: sequentially laying carbon fiber cloth and a carbon fiber net tire on a plate-shaped foam cushion layer, fixing the laid carbon fiber cloth and carbon fiber net tire by using a hand-pricking plate, and performing pre-needling to obtain a first layer of a first unit; needling the first layer, and rotating the needle plate by a fixed angle in the positive direction during needling; the prefabricated body obtained after needling is completed is subjected to clockwise rotation by a fixed angle every time and then laid, the first step and the second step are repeated till 360-degree rotation laying needling is completed, and needling of a first unit is completed; and repeating the step 1 to the step 3, completing needling of the second unit and the third unit, taking the three units as a repeat, and continuously carrying out laying and needling until the plate-shaped prefabricated body is completed. By designing different needling angles and adjusting the needling depth of the prefabricated body, the needling needle can enter the same vertical needling depth, Z-direction needling fibers with different depths are formed, and diversity of the Z-direction structure in the prefabricated body is achieved.

Description

Technical Field

[0001] This invention belongs to the field of materials technology in aerospace, automotive and photovoltaic industries, and in particular relates to a needle-punching method for plate-shaped preforms. Background Technology

[0002] During preform fabrication, the interlayer bonding depends on the length of the Z-axis fibers. In plate-shaped needle-punched preforms, the Z-axis fibers are typically fibers inserted vertically into the mesh by needles. The length of these fibers depends on the depth to which the needle penetrates the preform. For existing needle-punching technology, the needle-punching depth plays a crucial role in product quality. Deeper needle penetration results in longer Z-axis fibers and tighter interlayer bonding. However, excessively long Z-axis fibers can lead to over-punching, reduced fiber strength, and decreased product performance. Conversely, shallower needle penetration results in shorter Z-axis fibers, potentially causing delamination and serious quality problems. Therefore, controlling the Z-axis fiber depth in preforms is a significant technical challenge in ensuring preform quality. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the deficiencies in the prior art and proposes a needle-punching method for plate-shaped preforms. This needle-punching method, by designing different needle-punching angles and adjusting the needle-punching depth of the preform, changes the existing vertical needle-punching, achieving the same vertical needle-punching depth for the needles to penetrate, forming Z-direction needled fibers of different depths, and realizing the diversity of Z-direction structures within the preform.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] In a first aspect, the present invention provides a needle-punching method for a plate-shaped preform, the method comprising the following steps:

[0006] Step 1: Lay carbon fiber cloth and carbon fiber mesh on the board-shaped foam pad layer in sequence, fix the laid carbon fiber cloth and carbon fiber mesh with a hand tie, and perform pre-needling to obtain the first layer of the first unit. The direction of the pre-needling needles is perpendicular to the surface of the board-shaped foam pad layer.

[0007] Step 2: Acupuncture the first layer of the first unit. During acupuncture, rotate the needle plate in the positive direction to a fixed angle, and further fix the end to be acupunctured first before acupuncture.

[0008] Step 3: Rotate the preform that has been needled clockwise by a fixed angle each time and lay it up layer by layer. Repeat Step 1 and Step 2 until 360° rotational layering needled work is completed, thus completing the needled work of the first unit.

[0009] Step 4: Repeat steps 1 to 3 to complete the needle punching of the second and third units. Treat the three units as a repeat and continue to lay up and needle punch until the plate-shaped precast body is completed.

[0010] Furthermore, in step five, each unit needle plate in each repeating unit is needled at different positive and negative angles and at a perpendicular angle. Different preform requirements can be met by using different combinations of needled angles, and the repeating units can also be combined arbitrarily.

[0011] Furthermore, in the second unit, the needle plate rotates at a fixed angle in the negative direction during acupuncture, while in the third unit, the needle plate is perpendicular to the direction of acupuncture.

[0012] Furthermore, in step two, the rotation angle of the needle plate is between (0±30°), and the insertion depth of each layer of needles is the same in the vertical direction, ensuring that the fiber peeling strength is approximately the same in the vertical direction, while also ensuring the multi-directional structural strength of the preform.

[0013] Furthermore, when the precast structure is a square slab, the precast structure is rotated by 90° in step three. The rotation of each layer at a certain angle in step three depends on the shape of the precast structure. When the precast structure is a square slab, it is generally chosen to rotate the precast structure by 90° before laying the layers. Alternatively, other rotation angles can be designed according to the shape of the precast structure, and the number of layers in each unit will also change accordingly. Rotating each layer at a certain angle is also to stagger the needle-punching positions and ensure the structural strength of the precast structure.

[0014] Furthermore, in step three, before each layer of needle punching, the position of the needle punching should be staggered from the starting position of the previous layer to achieve staggered needle punching, ensuring that the needles are not in the same hole during each layer of needle punching, thus ensuring the uniformity of the internal structure of the precast body and the interlayer strength.

[0015] Furthermore, the carbon fiber cloth in step one is a non-woven fabric, a unidirectional fabric, or a plain weave fabric. Generally, the type of carbon fiber cloth selected and its areal density are determined according to different preform technical requirements.

[0016] This invention is based on the fabrication of a plate-shaped preform. Each unit layer consists of four layers of carbon fiber cloth and carbon fiber mesh, and each unit layer employs a needle-punching process at a different angle. Three unit layers are repeated to obtain the plate-shaped preform. Compared to existing vertical needle-punching processes, this invention uses needles at different angles to ensure that the vertical distance the needles travel into the preform is the same, but it allows for different adjustments to the Z-axis fiber length. Furthermore, the use of different needle-punching angles in each unit layer results in a disordered and uniform Z-axis fiber distribution in the preform, significantly enhancing its Z-axis strength.

[0017] Secondly, the present invention also provides a plate-shaped preform prepared by the above-described needle punching method.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This invention, by designing different needle-punching angles and adjusting the needle-punching depth of the preform, modifies the existing vertical needle-punching process to achieve the same vertical needle-punching depth, forming Z-axis needle-punched fibers of varying depths, thus realizing the diversity of Z-axis structures within the preform. Compared to existing vertical needle-punching processes, this invention allows for multi-angle needle-punching, achieving multi-directionality of the Z-axis structure in the preform, while also increasing the uniformity of Z-axis fibers and strengthening the interlayer structural strength of the preform. This invention has a wide range of applications and can be widely used in various plate-shaped preforms. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0025] The present invention will now be described in detail with reference to embodiments.

[0026] Example 1

[0027] A needle-punching method for a plate-shaped preform includes the following steps:

[0028] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 2 12K carbon fiber plain weave fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0029] Step 2: Insert the needle vertically, keeping the needle inserted vertically into the precast body to a depth of 15mm;

[0030] Step 3: Rotate the preform 90° clockwise, and lay the same carbon fiber cloth and carbon fiber mesh as in Step 1 and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needling of one unit.

[0031] Step 6: Repeat the needle punching of one unit until the entire preform is needle punched.

[0032] The Z-direction tensile strength of a sample with dimensions of 40×40×50mm (height) prepared in this embodiment was measured to be 0.038MPa, and the XY-direction tensile strength of a sample with dimensions of 120×25×10mm (height) was measured to be 10MPa. After subsequent processing, the compressive strength of the C / C composite material was 129MPa, the flexural strength was 70.2MPa, and the interlaminar shear strength was 12.5MPa.

[0033] Example 2

[0034] A needle-punching method for a plate-shaped preform includes the following steps:

[0035] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 2 12K carbon fiber plain weave fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0036] Step 2: Rotate the needle plate by +15° to perform acupuncture, keeping the needle perpendicular to the preform and inserting it to a depth of 15mm.

[0037] Step 3: Rotate the preform 90° clockwise, and lay the same carbon fiber cloth and carbon fiber mesh as in Step 1 and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needling of one unit.

[0038] Step 4: Lay out and fix the same carbon fiber cloth and carbon fiber mesh as in Step 1. Rotate the needle plate -15° to perform needle puncture. Also keep the needles vertical and enter the preform to a depth of 15mm. Then follow Step 3 until the needle puncture of one unit is completed.

[0039] Step 5: Lay out and fix the same carbon fiber cloth and carbon fiber mesh as in Step 1. Rotate the needle plate to the direction perpendicular to the preform and perform needle puncture. Also keep the needles perpendicular to the preform and insert them into the preform to a depth of 15mm. Then follow Step 3 until the needle puncture of one unit is completed.

[0040] Step 6: Repeat the needle punching of the above three units until the entire preform is needle punched.

[0041] The Z-direction tensile strength of a sample with dimensions of 40×40×50mm (height) prepared in this embodiment was measured to be 0.042 MPa, and the XY-direction tensile strength of a sample with dimensions of 120×25×10mm (height) was measured to be 15 MPa. After subsequent processing, the tensile strength of the C / C composite material was 167 MPa, the flexural strength was 139 MPa, and the interlaminar shear strength was 14 MPa.

[0042] Example 3

[0043] A needle-punching method for a plate-shaped preform includes the following steps:

[0044] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 212K carbon fiber plain weave fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0045] Step 2: Rotate the needle plate by +15° to perform acupuncture, keeping the needle perpendicular to the preform and inserting it to a depth of 15mm.

[0046] Step 3: Rotate the preform 90° clockwise, and lay the same carbon fiber cloth and carbon fiber mesh as in Step 1 and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needling of one unit.

[0047] Step 4: Lay out and fix the same carbon fiber cloth and carbon fiber mesh as in Step 1. Rotate the needle plate -15° to perform needle puncture. Also keep the needles vertical and enter the preform to a depth of 15mm. Then follow Step 3 until the needle puncture of one unit is completed.

[0048] Step 5: Repeat the needle punching of the above two units until the entire preform is needle punched.

[0049] The Z-direction tensile strength of a sample with dimensions of 40×40×50mm (height) prepared in this embodiment was measured to be 0.048MPa, and the XY-direction tensile strength of a sample with dimensions of 120×25×10mm (height) was measured to be 20.6MPa. After subsequent processing, the tensile strength of the C / C composite material was 221.6MPa, the flexural strength was 202MPa, and the interlaminar shear strength was 19MPa.

[0050] Example 4

[0051] A needle-punching method for a plate-shaped preform includes the following steps:

[0052] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 2 12K carbon fiber plain weave fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0053] Step 2: Rotate the needle plate by +15° to perform acupuncture, keeping the needle perpendicular to the preform and inserting it to a depth of 15mm.

[0054] Step 3: Rotate the preform 90° clockwise, and lay the same carbon fiber cloth and carbon fiber mesh as in Step 1 and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needling of one unit.

[0055] Step 4: Repeat the needle punching of one unit until the entire preform is needle punched.

[0056] The Z-direction tensile strength of a sample with dimensions of 40×40×50mm (height) was measured to be 0.039MPa from the preform prepared in this embodiment, and the XY-direction tensile strength of a sample with dimensions of 120×25×10mm (height) was measured to be 12.2MPa. After subsequent processing, the tensile strength of the C / C composite material was 134.2MPa, the flexural strength was 74.5MPa, and the interlaminar shear strength was 13.3MPa.

[0057] Example 5

[0058] A needle-punching method for a plate-shaped preform includes the following steps:

[0059] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 2 12K carbon fiber plain weave fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0060] Step 2: Rotate the needle plate by +8° to perform acupuncture, keeping the needle perpendicular to the preform and inserting it to a depth of 15mm.

[0061] Step 3: Rotate the preform 90° clockwise, and lay the same carbon fiber cloth and carbon fiber mesh as in Step 1 and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needling of one unit.

[0062] Step 4: Lay out and fix the same carbon fiber cloth and carbon fiber mesh as in Step 1. Rotate the needle plate -8° to perform needle puncture. Also keep the needles vertical and enter the preform to a depth of 15mm. Then follow Step 3 until the needle puncture of one unit is completed.

[0063] Step 6: Repeat the needle punching of the above two units until the entire preform is needle punched.

[0064] The Z-direction tensile strength of a sample with dimensions of 40×40×50mm (height) was measured in the preform prepared in this embodiment. The XY-direction tensile strength of a sample with dimensions of 120×25×10mm (height) was measured to be 21.2MPa. After subsequent processing, the tensile strength of the C / C composite material was 217MPa, the flexural strength was 158MPa, and the interlaminar shear strength was 17.9MPa.

[0065] Example 6

[0066] A needle-punching method for a plate-shaped preform includes the following steps:

[0067] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 2 12K carbon fiber plain weave fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0068] Step 2: Rotate the needle plate by +25° to perform acupuncture, keeping the needle perpendicular to the preform and inserting it to a depth of 15mm.

[0069] Step 3: Rotate the preform 90° clockwise, and lay the same carbon fiber cloth and carbon fiber mesh as in Step 1 and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needling of one unit.

[0070] Step 4: Lay out and fix the same carbon fiber cloth and carbon fiber mesh as in Step 1. Rotate the needle plate -25° to perform needle puncture. Also keep the needles vertical and enter the preform to a depth of 15mm. Then follow Step 3 until the needle puncture of one unit is completed.

[0071] Step 5: Repeat the needle punching of the above two units until the entire preform is needle punched.

[0072] The Z-direction tensile strength of a 40×40×50mm (height) sample from the preform prepared in this embodiment was measured to be 0.045 MPa, and the XY-direction tensile strength of a 120×25×10mm (height) sample was measured to be 18.3 MPa. After subsequent processing, the tensile strength of the C / C composite material was 201.6 MPa, the flexural strength was 180 MPa, and the interlaminar shear strength was 18.1 MPa.

[0073] Example 7

[0074] A needle-punching method for a plate-shaped preform includes the following steps:

[0075] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 2 12K carbon fiber nonwoven fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0076] Step 2: Rotate the needle plate by +15° to perform acupuncture, keeping the needle perpendicular to the preform and inserting it to a depth of 15mm.

[0077] Step 3: Rotate the preform 90° clockwise, lay the same carbon fiber cloth and carbon fiber mesh as in Step 1, and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needle punching of one unit layer. During the layering process, always keep the fiber direction of the carbon fiber cloth in the adjacent layers perpendicular to each other.

[0078] Step 4: Lay out and fix the same carbon fiber cloth and carbon fiber mesh as in Step 1. Rotate the needle plate -15° to perform needle puncture. Also keep the needles vertical and enter the preform to a depth of 15mm. Then follow Step 3 until the needle puncture of one unit is completed.

[0079] Step 5: Repeat the needle punching of the above two units until the entire preform is needle punched.

[0080] The Z-direction tensile strength of a 40×40×50mm (height) sample from the preform prepared in this embodiment was measured to be 0.049 MPa, and the XY-direction tensile strength of a 120×25×10mm (height) sample was measured to be 25.1 MPa. After subsequent processing, the tensile strength of the C / C composite material was found to be 228 MPa, the flexural strength to be 214 MPa, and the interlaminar shear strength to be 19.9 MPa.

[0081] Example 8

[0082] A needle-punching method for a plate-shaped preform includes the following steps:

[0083] Step 1: Cut a 500×500mm square foam pad and fix it on the equipment platform. The surface density is 280g / m³. 2 12K carbon fiber plain weave fabric is laid flat on the foam padding layer, and then a surface density of 80g / m² is added. 2 Short-cut carbon fiber mesh is laid on carbon fiber plain weave fabric, and then the laid carbon fiber fabric and carbon fiber mesh are fixed with a hand tie plate.

[0084] Step 2: Rotate the needle plate by +15° to perform acupuncture, keeping the needle perpendicular to the preform and inserting it to a depth of 15mm.

[0085] Step 3: Rotate the preform 60° clockwise, and lay the same carbon fiber cloth and carbon fiber mesh as in Step 1 and fix them. Keep the rotation angle of the needle plate and the depth of the needle into the preform unchanged. Repeat this process until the preform is rotated 360° clockwise to complete the needling of one unit.

[0086] Step 4: Lay out and fix the same carbon fiber cloth and carbon fiber mesh as in Step 1. Rotate the needle plate -15° to perform needle puncture. Also keep the needles vertical and enter the preform to a depth of 15mm. Then follow Step 3 until the needle puncture of one unit is completed.

[0087] Step 5: Repeat the needle punching of the above two units until the entire preform is needle punched.

[0088] The Z-direction tensile strength of a sample with dimensions of 40×40×50mm (height) was measured in the preform prepared in this embodiment. The XY-direction tensile strength of a sample with dimensions of 120×25×10mm (height) was measured to be 23.1MPa. After subsequent processing, the tensile strength of the C / C composite material was 227MPa, the flexural strength was 201MPa, and the interlaminar shear strength was 19.5MPa.

[0089] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A needle-punching method for a plate-shaped preform, characterized in that: The method includes the following steps: Step 1: Lay carbon fiber cloth and carbon fiber mesh on the board-shaped foam pad layer in sequence, fix the laid carbon fiber cloth and carbon fiber mesh with a hand tie, and perform pre-needling to obtain the first layer of the first unit. The direction of the pre-needling needles is perpendicular to the surface of the board-shaped foam pad layer. Step 2: Acupuncture the first layer of the first unit. During acupuncture, rotate the needle plate in the positive direction to a fixed angle, and further fix the end to be acupunctured first before acupuncture. Step 3: Rotate the preform that has been needled clockwise by a fixed angle each time and lay it up layer by layer. Repeat Step 1 and Step 2 until 360° rotational layering needled work is completed, thus completing the needled work of the first unit. Step 4: Repeat steps 1 to 3 to complete the needle punching of the second and third units. Treat the three units as a repeat and continue to lay up and needle punch until the plate-shaped precast body is completed.

2. The needle-punching method for the plate-shaped preform according to claim 1, characterized in that: In step five, each unit needle plate in each repeating unit is used for acupuncture at different positive and negative angles and at a vertical angle.

3. The needle-punching method for the plate-shaped preform according to claim 1, characterized in that: In the second unit, the needle plate rotates at a fixed angle in the negative direction during acupuncture, while in the third unit, the needle plate is perpendicular to the needle plate during acupuncture.

4. The needle-punching method for the plate-shaped preform according to claim 1, characterized in that: In step two, the rotation angle of the needle plate is between (0±30°), and the insertion depth of each layer of needles is the same in the vertical direction.

5. The needle-punching method for the plate-shaped preform according to claim 1, characterized in that: When the precast body is a square plate, the rotation angle of the precast body in step three is 90°.

6. The needle-punching method for the plate-shaped preform according to claim 1, characterized in that: In step three, before each layer of acupuncture is performed, the position is offset from the starting position of the previous layer of acupuncture to achieve staggered acupuncture.

7. The needle-punching method for the plate-shaped preform according to claim 1, characterized in that: The carbon fiber cloth in step one is a non-woven fabric, a unidirectional fabric, or a plain weave fabric.

8. A plate-shaped preform prepared by the acupuncture method according to any one of claims 1-7.