Large-size carbon fiber honeycomb core structure and preparation method

Abstract

This invention provides a large-size carbon fiber honeycomb core structure and its fabrication method, comprising: multiple sub-honeycomb core components; the sub-honeycomb core components are periodically arranged and bonded together to obtain a carbon fiber honeycomb core structure; the area of ​​the carbon fiber honeycomb core structure is greater than or equal to 4m². 2 The present invention features low mold manufacturing cost and simple operation. It adopts integrated molding of sub-honeycomb core components, and the bonding surface is treated with plasma, resulting in good bonding performance. The large-size carbon fiber honeycomb core has good overall performance, excellent thermal stability, and an extremely low coefficient of thermal expansion, making it suitable as the core material for high-stability large-size honeycomb sandwich panels.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to large-size carbon fiber honeycomb core structures and their preparation methods. "Large-size" refers to the fabrication size of the carbon fiber honeycomb core being greater than 2m. In other words, this invention pertains to the fabrication of large-size integrated carbon fiber honeycomb cores with a fabrication size exceeding 2m. Background Technology

[0002] Honeycomb structures can be made from a variety of materials, including metals, non-metals, paper, and polymers, and are widely used in various engineering applications such as aerospace, spacecraft, and transportation. Compared to these materials, carbon fiber reinforced composites exhibit higher specific stiffness, specific strength, and thermal stability. Carbon fiber honeycomb sandwich structures are particularly valuable due to their excellent high stability, with a thermal expansion coefficient <1 x 10⁻⁶. -6 The advantages of K-series satellites are gradually being applied in spacecraft such as communication and high-precision remote sensing satellites.

[0003] However, large-size carbon fiber honeycomb cores used in large communication and high-precision remote sensing satellites cannot yet be mass-produced rapidly. Currently, the main methods for preparing carbon fiber honeycomb core materials include: metal molding and splicing methods, and intercalation stretching methods.

[0004] Patent CN104842593A provides a method for preparing carbon fiber honeycomb core material by splicing. First, semi-hexagonal sub-components are prepared, and then the sub-components are bonded together in pairs. The method is simple to operate, but when preparing large-size products, the bonding workload is extremely large and the scalability is poor.

[0005] Patent CN105945246A discloses a method for preparing carbon fiber honeycomb core material by metal molding. The method uses a metal molding die to prepare carbon fiber honeycomb in one step, avoiding bonding and other processes. However, it has problems such as high die cost and complex die assembly for the preparation of large-size honeycomb cores.

[0006] Specifically, while the solution solves the problem of integrated molding of the honeycomb core, its technical solution implies a prerequisite: it must have a large, high-precision mold that is perfectly matched to the size of the target product.

[0007] Large molds present the following problems: First, the manufacturing cost of molds increases exponentially: the design, processing, heat treatment and assembly costs of large, high-precision molds are extremely high; Second, the difficulty of process implementation increases dramatically: it is extremely difficult to control the uniformity of mold closing, pressurization and heating of large molds, and the risk of product scrap is high; Third, the dimensional expandability is zero: the product size is locked by the mold size, and changing the size means reinvesting huge sums of money to manufacture a new mold.

[0008] Patent CN107379664A discloses a method for preparing carbon fiber honeycomb core material by intercalation stretching, but this method has the problem of high difficulty in actual intercalation and layup operations.

[0009] Therefore, with the development of space technology, spacecraft have increasingly higher requirements for high precision and high resolution, and their aperture sizes are constantly increasing. A modular prefabrication + secondary adhesive bonding assembly solution is urgently needed to address these issues. In other words, a method for fabricating large-size carbon fiber honeycomb cores is urgently needed. Summary of the Invention

[0010] In view of the shortcomings of the prior art, the purpose of this invention is to provide a large-size carbon fiber honeycomb core structure and its preparation method.

[0011] According to the present invention, a large-size carbon fiber honeycomb core structure includes: a plurality of sub-honeycomb core components; the sub-honeycomb core components are periodically arranged and bonded together to obtain a carbon fiber honeycomb core structure. The area of ​​the carbon fiber honeycomb core structure is greater than or equal to 4m². 2 .

[0012] Preferably, the material of the sub-cellular core assembly is a carbon fiber reinforced resin matrix composite.

[0013] A method for preparing a large-size carbon fiber honeycomb core structure according to the present invention includes: Step S1: Place the cut carbon fiber prepreg into the mold to obtain the mold after it is closed; Step S2: After the mold is closed, it is hot-pressed to form a honeycomb core component. Step S3: Plasma surface treatment is performed on the bonding surface of the sub-cell core assembly to bond the sub-cell core assembly. After bonding and curing, a large-size carbon fiber cell core is obtained.

[0014] Preferably, in step S1, the mold includes: a semi-hexagonal outer mold, a side outer mold, a regular hexagonal prism core mold, and a semi-hexagonal prism core mold; the upper surface of the semi-hexagonal outer mold is provided with a groove that matches the size of the honeycomb core of the carbon fiber honeycomb core; the size of the regular hexagonal prism core mold and the semi-hexagonal prism core mold matches the size of the honeycomb core of the carbon fiber honeycomb core.

[0015] Preferably, step S1 includes: Step A1: Lay carbon fiber prepreg on the semi-hexagonal outer mold, and place semi-hexagonal prism core molds at both ends of the semi-hexagonal outer mold. Fold the excess ends of the carbon fiber prepreg towards the semi-hexagonal prism core molds. Step A2: Place the regular hexagonal prism mandrel on top of the carbon fiber prepreg obtained in step A1, repeat step A1 until the layup is complete, and then close the mold.

[0016] Preferably, the carbon fiber prepreg is a non-woven prepreg with a thickness of 0.02 mm and a resin content of 30-35%.

[0017] Preferably, the material of the regular hexagonal prism core mold and the semi-hexagonal prism core mold is high-density polytetrafluoroethylene, and the material of its outer mold is mold steel.

[0018] Preferably, in step S2, the hot pressing process parameters include: hot pressing temperature 180℃, pressure 0.5-0.7Mpa, and holding time 50-80min.

[0019] Preferably, in step S3, plasma surface treatment is performed using a plasma surface treatment machine; the output power of the plasma surface treatment machine is 800W.

[0020] Preferably, in step S3, the adhesive used to bond the sub-cellular core assembly is epoxy resin.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. The carbon fiber honeycomb core structure provided by this invention has strong splicing ability, with good splicing ability in the W and L directions of the honeycomb core. Large-size honeycomb cores can be spliced ​​arbitrarily according to requirements, and splicing is convenient.

[0022] 2. The present invention has low mold manufacturing cost and simple operation. It adopts integrated molding of sub-honeycomb core components, and the bonding surface is treated with plasma, resulting in good bonding performance. The large-size carbon fiber honeycomb core has good overall performance, excellent thermal stability, and extremely low coefficient of thermal expansion, and can be used as the core material of high-stability large-size honeycomb sandwich panels.

[0023] 3. This invention improves the splicability of sub-cell core components, enables the preparation of large-size carbon fiber honeycomb core materials, significantly reduces the workload of bonding sub-cell core components, improves production efficiency, and enhances the continuity of carbon fiber honeycomb cores. Attached Figure Description

[0024] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the large-size carbon fiber honeycomb core material structure provided by the present invention; Figure 2 This is a schematic diagram of the splicing of sub-cell components of the carbon fiber honeycomb core material provided by the present invention; Figure 3 This is a schematic diagram of the process for preparing the carbon fiber honeycomb core material provided by the present invention. Detailed Implementation

[0025] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0026] This invention proposes a complete solution of "modular prefabrication + secondary adhesive bonding assembly". This solution is not a simple patchwork of existing technologies, but rather a comprehensive technical system formed by designing and providing dedicated standardized small molds, developing refined layup and folding processes, and combining targeted plasma surface treatment technology. This system not only fundamentally reduces the manufacturing cost and process difficulty of large-size honeycomb cores, enabling unlimited size expansion, but also ensures the superior performance of the final product through the synergistic effect of various technologies.

[0027] This invention provides a large-size carbon fiber honeycomb core structure and its preparation method. The large-size carbon fiber honeycomb core is formed by periodically arranging and bonding multiple sub-honeycomb core components of the same specifications. The preparation method includes the following steps: laying up carbon fiber prepreg, hot pressing and curing, plasma surface treatment, and bonding of sub-honeycomb core components.

[0028] According to the present invention, a large-size carbon fiber honeycomb core structure is formed by periodically arranging and bonding multiple identical sub-honeycomb core components; the area of ​​the carbon fiber honeycomb core can reach 4m². 2 The carbon fiber honeycomb core material is a carbon fiber reinforced resin matrix composite material.

[0029] Specifically, according to the present invention, a method for preparing a large-size carbon fiber honeycomb core includes: a. The cut carbon fiber prepreg is laid in the mold according to the design requirements. The mold includes a semi-hexagonal outer mold, a side outer mold, a regular hexagonal prism core mold, and a semi-hexagonal prism core mold. The upper surface of the semi-hexagonal outer mold is designed with grooves that match the size of the honeycomb lattice. The sizes of the regular hexagonal prism core mold and the semi-hexagonal prism core mold match the size of the honeycomb lattice.

[0030] b. During the laying process, first, install the carbon fiber prepreg on the semi-hexagonal outer mold at the required layup angle. Place semi-hexagonal core molds at both ends of the outer mold, fold the excess ends of the carbon fiber prepreg towards the semi-hexagonal core molds, and then place the regular hexagonal prism core molds on top of the laid carbon fiber prepreg. Then, repeat the above steps on top of the core molds to lay the second layer. Repeat the above steps until the layup is complete. After the layup is completed, close the mold.

[0031] c. Place the mold, after it has been closed, into a hot press to solidify it. After solidification, demold to obtain the sub-honeycomb core assembly.

[0032] d. The outer bonding surfaces of the obtained sub-cell core assembly are subjected to plasma surface treatment to improve bonding performance. In other words, after the obtained sub-cell core assembly is bonded and cured, a large-size carbon fiber honeycomb core is obtained.

[0033] e. After bonding and curing the obtained sub-cell honeycomb core components, a large-size carbon fiber honeycomb core is obtained.

[0034] Specifically, the carbon fiber prepreg is a non-woven prepreg with a thickness of 0.02 mm and a resin content of 30-35%.

[0035] Specifically, in step a, the material of the regular hexagonal prism core mold and the semi-hexagonal prism core mold is high-density polytetrafluoroethylene, and the material of the outer mold is mold steel.

[0036] Specifically, the hot pressing process parameters in step c are: hot pressing temperature 180℃, pressure 0.5-0.7Mpa, and holding time 50-80min.

[0037] Specifically, the parameters of the plasma surface treatment machine in step d are: output power 800W.

[0038] Specifically, the adhesive in step e is epoxy resin.

[0039] In the embodiments, in the large-size carbon fiber honeycomb core structure and preparation method provided by the present invention, the material used for the carbon fiber honeycomb core is carbon fiber nonwoven prepreg with a thickness of 0.02 mm and a resin content of 30-35%.

[0040] The regular hexagonal prism core mold 3 and the semi-hexagonal prism core mold 4 are made of high-density polytetrafluoroethylene, and the outer molds 1, 2 and 5 are made of mold steel.

[0041] The method for preparing large-size carbon fiber honeycomb cores includes the following steps: a. The cut carbon fiber prepreg is laid in the mold according to the design requirements. The mold includes semi-hexagonal outer molds 1 and 5, side outer molds 2, regular hexagonal prism core mold 3, and semi-hexagonal prism core mold 4. The surfaces of the semi-hexagonal outer molds 1 and 5 are designed with grooves that match the size of the honeycomb core. The sizes of the regular hexagonal prism core mold 3 and the semi-hexagonal prism core mold 4 match the size of the honeycomb core.

[0042] Specifically, each of the honeycomb cells is a hexagonal cell obtained by combining the molds; the size of the honeycomb cell is a preset value, and the size of the mold is set according to the preset value.

[0043] Specifically, the semi-hexagonal prism core mold 4 is half of the regular hexagonal prism core mold 3; the missing part of the semi-hexagonal prism core mold 4 is symmetrical about the semi-hexagonal prism core mold 4, and the axis of symmetry is perpendicular to the two opposite sides.

[0044] b. During the laying process, first lay the carbon fiber prepreg 6 on the semi-hexagonal outer mold 1 according to the required layup angle. Place the semi-hexagonal core mold, i.e., the semi-hexagonal prism core mold 4, at both ends of the outer mold. Fold the excess ends of the carbon fiber prepreg towards the semi-hexagonal prism core mold. Then place the regular hexagonal prism core mold on top of the laid carbon fiber prepreg 6. Then repeat the above steps on top of the core mold to lay the second layer. Repeat the above steps until the layup is completed. After the layup is completed, close the mold.

[0045] c. Place the mold after mold closing into a hot press for solidification. The molding conditions are: hot pressing temperature 180℃, pressure 0.5-0.7Mpa, and holding time 50-80min. After solidification, demold to obtain the sub-honeycomb core component 7.

[0046] d. The surface of the splicing joint of the obtained sub-cell core component 7 is subjected to plasma surface treatment to improve the bonding strength. The plasma output power is 800W.

[0047] e. Use epoxy resin as an adhesive to bond the obtained sub-honeycomb core components, and after curing at room temperature, obtain a large-size carbon fiber honeycomb core.

[0048] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, 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 this application.

[0049] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A large-size carbon fiber honeycomb core structure, characterized in that, include: Multiple sub-cell core components; The sub-honeycomb core components are periodically arranged and bonded together to obtain a carbon fiber honeycomb core structure; The area of ​​the carbon fiber honeycomb core structure is greater than or equal to 4m². 2 .

2. The large-size carbon fiber honeycomb core structure according to claim 1, characterized in that, The sub-cellular core assembly is made of carbon fiber reinforced resin-based composite material.

3. A method for preparing a large-size carbon fiber honeycomb core structure, used to prepare the large-size carbon fiber honeycomb core structure according to any one of claims 1 or 2, characterized in that, include: Step S1: Place the cut carbon fiber prepreg into the mold to obtain the mold after it is closed; Step S2: After the mold is closed, it is hot-pressed to form a honeycomb core component. Step S3: Plasma surface treatment is performed on the bonding surface of the sub-cell core assembly to bond the sub-cell core assembly. After bonding and curing, a large-size carbon fiber cell core is obtained.

4. The method for preparing a large-size carbon fiber honeycomb core structure according to claim 3, characterized in that, In step S1, the mold includes: a semi-hexagonal outer mold, a side outer mold, a regular hexagonal prism core mold, and a semi-hexagonal prism core mold; the upper surface of the semi-hexagonal outer mold is provided with a groove that matches the size of the honeycomb core of the carbon fiber honeycomb core; the size of the regular hexagonal prism core mold and the semi-hexagonal prism core mold matches the size of the honeycomb core of the carbon fiber honeycomb core.

5. The method for preparing a large-size carbon fiber honeycomb core structure according to claim 4, characterized in that, Step S1 includes: Step A1: Lay carbon fiber prepreg on the semi-hexagonal outer mold, and place semi-hexagonal prism core molds at both ends of the semi-hexagonal outer mold. Fold the excess ends of the carbon fiber prepreg towards the semi-hexagonal prism core molds. Step A2: Place the regular hexagonal prism mandrel on top of the carbon fiber prepreg obtained in step A1, repeat step A1 until the layup is complete, and then close the mold.

6. The method for preparing a large-size carbon fiber honeycomb core structure according to claim 3, characterized in that, The carbon fiber prepreg is a non-woven prepreg with a thickness of 0.02 mm and a resin content of 30-35%.

7. The method for preparing a large-size carbon fiber honeycomb core structure according to claim 4, characterized in that, The material of the regular hexagonal prism core mold and the semi-hexagonal prism core mold is high-density polytetrafluoroethylene, and the material of its outer mold is mold steel.

8. The method for preparing a large-size carbon fiber honeycomb core structure according to claim 3, characterized in that, In step S2, the hot pressing process parameters include: hot pressing temperature 180℃, pressure 0.5-0.7Mpa, and holding time 50-80min.

9. The method for preparing a large-size carbon fiber honeycomb core structure according to claim 3, characterized in that, In step S3, plasma surface treatment is performed using a plasma surface treatment machine; the output power of the plasma surface treatment machine is 800W.

10. The method for preparing a large-size carbon fiber honeycomb core structure according to claim 3, characterized in that, In step S3, the adhesive used to bond the sub-cell core assembly is epoxy resin.

Images