Bionic rib type carbon / carbon honeycomb sandwich structure and construction method and application thereof

Abstract

The invention belongs to the technical field of high-performance composite materials, and particularly discloses a bionic rib type carbon / carbon honeycomb sandwich structure and a construction method and application thereof.The bionic rib type carbon / carbon honeycomb sandwich structure comprises a C / C composite material upper panel, a multi-scale rib reinforced core layer and a C / C composite material lower panel which are arranged from top to bottom; the multi-scale rib reinforced core layer comprises a low-density C / C honeycomb matrix and a high-density carbonaceous reinforced rod, and the high-density carbonaceous reinforced rod is selectively embedded into a stress cell circle of the low-density C / C honeycomb matrix based on a finite element simulation analysis result under a compression load. According to the bionic rib type carbon / carbon honeycomb sandwich structure and the construction method and application thereof, the specific strength and the specific stiffness are further improved while the weight is reduced, flexible design and combination are conducted according to the actual load condition, and the customization requirements of different application scenes are met.

Description

A biomimetic rib-like carbon / carbon honeycomb sandwich structure, its construction method and application Technical Field

[0001] This invention relates to the field of high-performance composite materials technology, and in particular to a biomimetic rib-like carbon / carbon honeycomb sandwich structure, its construction method, and its application. Background Technology

[0002] C / C composite materials are ideal for manufacturing hot-end components of aerospace vehicles due to their excellent high-temperature mechanical properties, low density, and good thermal shock resistance. The novel carbon / carbon (C / C) honeycomb sandwich structure inherits the high-temperature mechanical properties of C / C composite materials, while further leveraging its lightweight advantage, thus meeting the requirements of load-bearing platform structures for ultra-high stability, lightweight design, and high load-bearing capacity.

[0003] In existing technologies, traditional homogeneous C / C honeycomb core materials are prone to cell wall buckling or crushing under out-of-plane compression and bending loads, resulting in insufficient overall load-bearing capacity and stiffness. Simply increasing the honeycomb density or panel thickness to improve performance would significantly sacrifice its lightweight advantage. Therefore, how to fundamentally improve the core mechanical properties of sandwich structures with minimal increase in mass has become a pressing technical challenge in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a biomimetic ribbed carbon / carbon honeycomb sandwich structure, its construction method and application, which is lightweight while further improving specific strength and specific stiffness. It can be flexibly designed and combined according to actual load conditions to meet the customized needs of different application scenarios.

[0005] To achieve the above objectives, the present invention provides a biomimetic rib-like carbon / carbon honeycomb sandwich structure, comprising a C / C composite material upper panel, a multi-scale rib-reinforced core layer, and a C / C composite material lower panel arranged from top to bottom. The multi-scale rib-reinforced core layer comprises a low-density C / C honeycomb matrix and a high-density carbon reinforcing rod. Based on finite element simulation analysis results under compressive load, the high-density carbon reinforcing rod is selectively embedded in the stress-bearing cell of the low-density C / C honeycomb matrix. The high-density carbon reinforcing rod is bonded to the inner wall of the stress-bearing cell of the low-density C / C honeycomb matrix, the multi-scale rib-reinforced core layer is bonded to the upper panel of the C / C composite material, and the multi-scale rib-reinforced core layer is bonded to the lower panel of the C / C composite material through adhesive films.

[0006] Preferably, the density of the low-density C / C honeycomb matrix is ​​0.8-1.2 g / cm³. 3 The density of the high-density carbonaceous reinforcing rod is 1.4-1.6 g / cm³. 3The low-density C / C honeycomb matrix serves as the load-bearing matrix, while the high-density carbonaceous reinforcing rods act as reinforcing ribs.

[0007] Preferably, the diameter D of the high-density carbon reinforcing rod is matched proportionally to the side-to-side distance S of the stressed cell circle, with the matching ratio ranging from 0.98 ≤ D / S ≤ 1.0.

[0008] Preferably, the high-density carbon reinforcing rod does not fill all stress cells, but is selectively embedded in designated stress cells with the greatest or most critical stress based on the results of mechanical simulation analysis.

[0009] Preferably, the diameter of the high-density carbon reinforcing rod is selected from one or more of 4.9 mm, 8.9 mm, and 14.9 mm.

[0010] Preferably, the height of the high-density carbonaceous reinforcing rod is equal to the height of the low-density C / C honeycomb matrix.

[0011] Preferably, the adhesive film is an organic adhesive film or an inorganic adhesive film, and the inorganic adhesive film is a high-temperature resistant inorganic adhesive film.

[0012] Preferably, the high-temperature resistant inorganic film is a polycarbosilane precursor or a silicon boron carbon nitride precursor system film.

[0013] This invention also provides a method for constructing a biomimetic rib-like carbon / carbon honeycomb sandwich structure, comprising the following steps: S1, structural design: finite element modeling and optimization analysis are performed based on the service compression load to determine the position, number, and diameter of the high-density carbon reinforcing rods to be embedded in the stress-bearing cell, and a low-density C / C honeycomb matrix is ​​woven in; S2, preparation of multi-scale rib-reinforced core layer: an adhesive film is coated or pre-placed between the high-density carbon reinforcing rods and the inner wall of the stress-bearing cell of the low-density C / C honeycomb matrix obtained in S1, and then the high-density carbon reinforcing rods of selected diameter are precisely inserted into the stress-bearing cell, and the core is bonded by hot pressing to form a multi-scale rib-reinforced core layer; S3, overall composite: an adhesive film is covered on the upper and lower surfaces of the multi-scale rib-reinforced core layer obtained in S2, and assembled with the upper panel and lower panel of the C / C composite material respectively, and cured by hot pressing to completely cross-link the adhesive film to obtain a carbon / carbon honeycomb sandwich structure.

[0014] Preferably, in S1, the finite element modeling and optimization analysis specifically involves minimizing the overall mass of the carbon / carbon honeycomb sandwich structure while meeting the target stiffness and strength requirements, thereby obtaining the arrangement position, quantity, and diameter combination of high-density carbon reinforcing rods in the low-density C / C honeycomb matrix.

[0015] Preferably, in S2, the hot pressing treatment temperature is 150-250℃, the pressure is 1-5MPa, and the holding time is 120-180min.

[0016] Preferably, in S3, the temperature of the hot pressing curing process is 120-150℃, the pressure is 1-5MPa, and the holding time is 120-180min.

[0017] Preferably, before hot pressing, the connecting surfaces of the high-density carbon reinforcing rod, the low-density C / C honeycomb matrix, the C / C composite upper panel, and the C / C composite lower panel are subjected to fine pretreatment to enhance the interfacial bonding ability. The pretreatment includes surface cleaning, roughening treatment, and chemical activation treatment.

[0018] This invention also provides an application of a biomimetic rib-like carbon / carbon honeycomb sandwich structure in the fabrication of hot-end components for hypersonic aircraft and lightweight, high-load-bearing structural platforms.

[0019] Therefore, the present invention employs the aforementioned biomimetic rib-like carbon / carbon honeycomb sandwich structure, its construction method, and its application, with the following beneficial effects: The present invention significantly improves the mechanical properties of the structure, such as compression and bending, with minimal mass cost through multi-scale collaborative design; it achieves optimal material distribution using finite element optimization, avoiding unnecessary mass increases; it ensures strong interface between components and smooth stress transmission through inorganic adhesive film bonding technology; and the diameter and arrangement of the reinforcing rods can be flexibly designed and combined according to actual load conditions to meet the customized needs of different application scenarios.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 is a flowchart of the biomimetic rib-type carbon / carbon honeycomb sandwich structure, its construction method, and application embodiment one of the present invention; Figure 2 is a structural schematic diagram of the multi-scale rib-reinforced core layer of the biomimetic rib-type carbon / carbon honeycomb sandwich structure, its construction method, and application embodiment two of the present invention; Figure 3 is a schematic diagram of the compression process of the biomimetic rib-type carbon / carbon honeycomb sandwich structure, its construction method, and application embodiment of the present invention; Figure 4 is a graph showing the change in compression ratio strength of the biomimetic rib-type carbon / carbon honeycomb sandwich structure, its construction method, and application embodiment of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0024] Example 1: As shown in Figure 1, a biomimetic ribbed carbon / carbon honeycomb sandwich structure is constructed using an optimization design based on finite element method (FEM) simulation. First, structural optimization is performed through FEM simulation. A parametric model is established, comprising a C / C composite panel, a low-density C / C honeycomb matrix, and high-density carbon reinforcing rods. The thickness of the C / C composite panel is set to 1.5-2.5 mm, the height of the low-density C / C honeycomb matrix is ​​10-15 mm, and the cell circle to edge distances are 5 mm, 9 mm, and 15 mm, respectively. The high-density carbon reinforcing rods have edge lengths of 4.9 mm, 8.9 mm, and 14.9 mm. During the simulation, the out-of-plane compressive displacement is set to 1.5-6 mm according to the actual application scenario, and the actual support boundary conditions are accurately simulated. Parameter optimization is performed through iterative calculations, with the objective function of "minimizing mass while meeting stiffness requirements." High-stress areas and key force transmission paths are identified, and the optimal layout scheme of the high-density carbon reinforcing rods, including their position distribution, quantity ratio, and diameter combination, is finally determined.

[0025] During the material preparation stage, materials with a density of 0.9-1.1 g / cm³ are selected. 3 The low-density C / C honeycomb matrix has a density of 1.4-1.6 g / cm³. 3 The high-density carbon fiber reinforcing rods are used, with their height strictly controlled to match the height of the low-density C / C honeycomb core, within a tolerance of ±0.1 mm. Surface treatment processes include sandblasting of the hexagonal sidewalls of the high-density carbon fiber reinforcing rods, with a roughness Ra controlled between 2.5-4.0 μm, and plasma cleaning of the low-density C / C honeycomb core walls to thoroughly remove surface contaminants. Adhesive film pretreatment involves appropriate activation treatment based on the selected adhesive film type. For organic adhesive film systems, modified epoxy resin films are used, with an applicable temperature ≤300℃; for inorganic adhesive film systems, polycarbosilane precursor films are used, with an applicable temperature ≥1000℃.

[0026] During assembly, a visual positioning system is used to ensure precise insertion of the high-density carbon fiber reinforcing rod into the designated cell circle, with a positional deviation of ≤0.2mm. After pre-applying an adhesive film between the hexagonal sidewall of the high-density carbon fiber reinforcing rod and the honeycomb core wall of the low-density C / C honeycomb matrix, a hot-press curing process is performed with parameters set at 200℃, 2MPa, and 120min. Pressure distribution and temperature uniformity are monitored in real time during curing. After curing, the interface bonding quality is tested using ultrasound to ensure good adhesion within the core layer.

[0027] Before overall lamination, the upper and lower surfaces of the multi-scale reinforcing core layer are mechanically polished to increase roughness, and the bonding surfaces of the C / C composite upper and lower panels are chemically treated to improve surface activity. Subsequently, a continuous adhesive film layer is laid on the upper and lower surfaces of the multi-scale reinforcing core layer, with the film thickness controlled at 0.2-0.5 mm to ensure complete coverage of the end faces of the high-density carbon reinforcing rods. The selected adhesive film type is compatible with the adhesive film system inside the core layer.

[0028] During the overall assembly process, the sequence is as follows: C / C composite lower panel, adhesive film, multi-scale reinforcing core layer, adhesive film, and C / C composite upper panel. Hot-press curing parameters are set at 130℃, 2MPa, and 60 minutes, with particular emphasis on ensuring uniform pressure distribution in the contact area between the high-density carbon reinforcing rod and the panel. Different post-treatment processes are employed depending on the adhesive film system: inorganic adhesive film systems undergo high-temperature heat treatment to improve interfacial bonding strength, while organic adhesive film systems utilize a stepped cooling process to eliminate internal stress.

[0029] Example 2: A biomimetic rib-like carbon / carbon honeycomb sandwich structure, based on Example 1, uses high-density carbon reinforcing rods with a diameter of 9mm and a low-density C / C honeycomb matrix of 8×8×1.5cm, with a total volume of 96cm³. 3 The material consists of four high-density carbon reinforcing rods, arranged as shown in Figure 2. The material density is 0.29 g / cm³. 3 , marked as 1 / 2 / 3 / 4-4.

[0030] Comparative Example 1: The difference from Example 2 lies in the number (layout) of high-density carbon reinforcing rods and the material density. No high-density carbon reinforcing rods were used, and the material density was 0.10 g / cm³. 3 , marked as 1-0.

[0031] Comparative Example 2: The difference from Example 2 lies in the number (layout) of the high-density carbon reinforcing rods and the material density. One high-density carbon reinforcing rod is used, positioned in the middle of the multi-scale rib-reinforcing core layer, and the material density is 0.15 g / cm³. 3 , marked as 2-1.

[0032] Comparative Example 3: The difference from Example 2 lies in the number (layout) of high-density carbon reinforcing rods and the material density. Two high-density carbon reinforcing rods are used, positioned at positions 1 and 2 of the multi-scale rib-reinforcing core layer. The material density is 0.195 g / cm³. 3 , marked as 3-1 / 2.

[0033] Comparative Example 4: The difference from Example 2 lies in the number (layout) of high-density carbon reinforcing rods and the material density. The number of high-density carbon reinforcing rods is 2, and the material density is 0.20 g / cm³. 3 The layout scheme is to set it at positions 1 and 4 of the multi-scale rib-reinforced core layer, marked as 4-1 / 4.

[0034] Experimental testing: Compression tests were conducted on the carbon / carbon honeycomb sandwich structures of Example 2 and Comparative Examples 1-4. The compression process is shown in Figure 3. The compression performance test results and compression ratio results are shown in Table 1 and Figure 4, respectively.

[0035] Table 1. Test results of 9mm compression performance

[0036] As shown in Table 1, as the number of high-density carbon reinforcing rods increases from 0 to 4, the material density increases from 0.10 g / cm³. 3 Increased to 0.29 g / cm³ 3 The increase reached 190%, while the corresponding out-of-plane compressive strength increased significantly from 2.66MPa to 14.83MPa, an increase of 457%, which fully demonstrates that the strength increase is much greater than the density increase, and the reinforcement efficiency is extremely excellent.

[0037] As shown in Figure 4, the variation in the strength / density ratio is particularly noteworthy. This ratio continuously increases from a baseline of 1.00 to an optimal 2.41, indicating a significant improvement in structural efficiency. In comparing different layouts of the same number of high-density carbon fiber reinforcing rods, significant differences in strength were found even with similar mass. For example, the layout with two high-density carbon fiber reinforcing rods achieved a strength of 8.00 MPa, strongly demonstrating the significant impact of the placement of these rods on performance. Through systematic optimization, four high-density carbon fiber reinforcing rods were determined to be the optimal performance scheme. Using four reinforcing rods with optimized distribution based on stress concentration areas, excellent performance was achieved with an out-of-plane compressive strength of 14.83 MPa and a specific strength of 51.1 kN·m / kg. Two high-density carbon fiber reinforcing rods offered the best cost-effectiveness, achieving a 201% increase in strength and a reinforcement efficiency of 2.01 with only a 100% increase in density.

[0038] Therefore, the present invention adopts the above-mentioned biomimetic rib-type carbon / carbon honeycomb sandwich structure and its construction method and application, which is lightweight while further improving specific strength and specific stiffness. It can be flexibly designed and combined according to actual load conditions to meet the customized needs of different application scenarios.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A biomimetic rib-like carbon / carbon honeycomb sandwich structure, characterized in that: The device comprises a C / C composite material top panel, a multi-scale reinforcing core layer, and a C / C composite material bottom panel arranged from top to bottom. The multi-scale reinforcing core layer includes a low-density C / C honeycomb matrix and a high-density carbon fiber reinforcing rod. The high-density carbon fiber reinforcing rod is selectively embedded in the stress-bearing cell of the low-density C / C honeycomb matrix based on finite element simulation analysis results under compressive load. The high-density carbon fiber reinforcing rod is bonded to the inner wall of the stress-bearing cell of the low-density C / C honeycomb matrix, the multi-scale reinforcing core layer is bonded to the C / C composite material top panel, and the multi-scale reinforcing core layer is bonded to the C / C composite material bottom panel through adhesive films.

2. The biomimetic rib-like carbon / carbon honeycomb sandwich structure according to claim 1, characterized in that: The density of the low-density C / C honeycomb matrix is ​​0.8-1.2 g / cm³. 3 The density of the high-density carbonaceous reinforcing rod is 1.4-1.6 g / cm³. 3 .

3. The biomimetic rib-like carbon / carbon honeycomb sandwich structure according to claim 1, characterized in that: The diameter D of the high-density carbon reinforcing rod is matched proportionally to the side-to-side distance S of the stressed cell circle, with a matching ratio range of 0.96≤D / S≤1.

0.

4. The biomimetic rib-like carbon / carbon honeycomb sandwich structure according to claim 1, characterized in that: The diameter of the high-density carbon reinforcing rod is selected from one or more of 5 mm, 9 mm, and 15 mm.

5. The biomimetic rib-like carbon / carbon honeycomb sandwich structure according to claim 1, characterized in that: The height of the high-density carbonaceous reinforcing rod is equal to the height of the low-density C / C honeycomb matrix.

6. The biomimetic rib-like carbon / carbon honeycomb sandwich structure according to claim 1, characterized in that: The adhesive film is an organic adhesive film or an inorganic adhesive film, and the inorganic adhesive film is a high-temperature resistant inorganic adhesive film.

7. A method for constructing a biomimetic rib-like carbon / carbon honeycomb sandwich structure, characterized in that, Includes the following steps: S1. Structural Design: Based on the service compression load, finite element modeling and optimization analysis are performed to determine the position, number, and diameter of the high-density carbon reinforcing rods to be embedded in the stress-bearing cells, and a low-density C / C honeycomb matrix is ​​woven in. S2. Preparation of Multi-Scale Rib Reinforced Core Layer: An adhesive film is coated or pre-placed between the high-density carbon reinforcing rods and the inner wall of the stress-bearing cells of the low-density C / C honeycomb matrix obtained in S1. Then, the high-density carbon reinforcing rods of the selected diameter are precisely inserted into the stress-bearing cells, and the core is bonded by hot pressing to form a multi-scale rib reinforced core layer. S3. Overall Composite: An adhesive film is covered on the upper and lower surfaces of the multi-scale rib reinforced core layer obtained in S2, and assembled with the upper and lower panels of the C / C composite material, respectively. After hot pressing and curing, the adhesive film is completely cross-linked to obtain a carbon / carbon honeycomb sandwich structure.

8. The method for constructing a biomimetic rib-like carbon / carbon honeycomb sandwich structure according to claim 7, characterized in that, In S1, the finite element modeling and optimization analysis specifically refers to minimizing the overall mass of the carbon / carbon honeycomb sandwich structure while meeting the target stiffness and strength requirements, and obtaining the arrangement position, quantity, and diameter combination of high-density carbon reinforcing rods in the low-density C / C honeycomb matrix.

9. The method for constructing a biomimetic rib-like carbon / carbon honeycomb sandwich structure according to claim 7, characterized in that, In S2, the hot pressing treatment is performed at a temperature of 150-250℃, a pressure of 1-5MPa, and a holding time of 120-180min.

10. The application of a carbon / carbon honeycomb sandwich structure prepared by the construction method of the biomimetic rib-type carbon / carbon honeycomb sandwich structure as described in any one of claims 1-6 or any one of claims 7-9 in the preparation of hot-end components of hypersonic aircraft and lightweight high-load-bearing structural platforms.

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