An integrated honeycomb sandwich structure resistant to high energy laser ablation

Abstract

The application provides an integrated honeycomb sandwich structure resistant to high-energy laser ablation, which comprises a honeycomb core, a composite material skin covering the front surface of the honeycomb core and an aluminum alloy skin covering the back surface of the honeycomb core; the composite material skin comprises a high reflectivity layer located at the outermost layer, a high conductivity layer located at the middle layer and an aluminum alloy layer located at the innermost layer; the honeycomb core is a honeycomb core filled with a light ablation material and a thermal insulation material, which comprises a honeycomb core base, a light ablation material layer covering the front surface of the honeycomb core base and in contact with the back surface of the aluminum alloy layer and a light thermal insulation material layer covering the back surface of the honeycomb core base; the aluminum alloy skin is in contact with the back surface of the light thermal insulation material layer. The application has reasonable structure design, is safe and convenient to prepare, can meet the design requirements of lightweight structure and greatly enhances the ablation resistance of the integrated honeycomb sandwich structure.

Description

Technical Field

[0001] This invention relates to the technical field of high-energy laser protection research, specifically to an integrated honeycomb sandwich structure resistant to high-energy laser ablation. Background Technology

[0002] With the rapid development of high-energy laser technology, its applications in space system protection, aerospace equipment, advanced weapon platforms, and critical infrastructure protection are becoming increasingly widespread. However, the problems of material ablation, melting, vaporization, and structural failure caused by high-energy lasers are becoming increasingly prominent. High-energy lasers are characterized by high power density, concentrated energy, and controllable exposure time. During irradiation, they can create intense heat accumulation and severe thermo-mechanical-phase transition coupling effects on material surfaces, easily leading to drastic local temperature rises, accelerated ablation, and a sharp degradation of overall mechanical properties in load-bearing structures, thus seriously threatening structural safety and service reliability.

[0003] Existing laser ablation resistant structures are mostly based on single-material protection or simple layered structures, such as high-melting-point ceramic coatings, metal-based heat-resistant layers, or thermally insulating composite materials. While these structures can delay the transfer of laser energy to the substrate to some extent, they generally suffer from problems such as difficulty in balancing ablation resistance and load-bearing capacity, susceptibility to interface failure, low overall structural efficiency, and insufficient long-term service stability. Especially under prolonged or repeated high-energy laser irradiation, traditional structures are prone to failure modes such as coating peeling, interlayer debonding, and localized collapse, making it difficult to meet the comprehensive requirements of lightweight, high strength, and high heat resistance protection.

[0004] Honeycomb sandwich structures are widely used in aerospace and protective engineering due to their advantages such as high specific strength, high specific stiffness, and strong energy absorption capacity. However, most existing honeycomb sandwich structures focus on mechanical or thermal insulation performance design, and lack systematic protection capabilities against high-energy laser ablation environments. Furthermore, the honeycomb core layer and the panel are usually connected by adhesive or mechanical means, resulting in a low degree of structural integration. Under high temperature and strong thermal shock conditions, interface degradation and overall performance degradation are likely to occur.

[0005] Therefore, there is an urgent need to propose an integrated ablation-resistant honeycomb sandwich structure for high-energy laser ablation environments. Through structural design and material synergy, the structure can effectively dissipate laser energy and diffuse heat, while taking into account load-bearing capacity, structural integrity and service reliability, thereby improving the overall protection performance and engineering application value of the structure under high-energy laser conditions. Summary of the Invention

[0006] To address the technical problems existing in the background art described above, this invention proposes an integrated honeycomb sandwich structure resistant to high-energy laser ablation.

[0007] To solve the above-mentioned technical problems, the present invention provides an integrated honeycomb sandwich structure resistant to high-energy laser ablation, which includes a honeycomb core, a composite material skin covering the front side of the honeycomb core, and an aluminum alloy skin covering the back side of the honeycomb core.

[0008] The composite material skin includes an outermost high reflectivity layer, a middle high conductivity layer, and an innermost aluminum alloy layer.

[0009] The honeycomb core is a honeycomb core filled with lightweight ablation material and thermal insulation material, which includes a honeycomb core substrate, a lightweight ablation material layer covering the front side of the honeycomb core substrate and in contact with the back side of the aluminum alloy layer, and a lightweight thermal insulation material layer covering the back side of the honeycomb core substrate.

[0010] The aluminum alloy skin is in contact with the back side of the lightweight thermal insulation material layer.

[0011] As a preferred embodiment of the present invention: the composite material skin and the honeycomb core are connected together by high-temperature adhesive curing; the aluminum alloy skin and the honeycomb core are bonded together by adhesive.

[0012] As a preferred embodiment of the present invention: the high reflectivity layer is an aluminum alloy layer made of ALCLAD2024-T3; the high conductivity layer is made of a high thermal conductivity graphite film material with a thermal conductivity of 800 W / (m·K), and its front side is in contact with the back side of the high reflectivity layer; the front side of the aluminum alloy layer is in contact with the back side of the high conductivity layer.

[0013] As a preferred embodiment of the present invention: the thickness of the high conductivity layer is 0.1 mm; the thickness of the aluminum alloy layer is 0.2 mm.

[0014] As a preferred embodiment of the present invention, the high reflectivity layer, the high conductivity layer and the aluminum alloy layer are pressed together under high temperature and high pressure in a vacuum environment to form the composite material skin.

[0015] As a preferred embodiment of the present invention, the process parameters for pressing under high temperature and high pressure in a vacuum environment include:

[0016] Vacuum level: less than 1×10 -3 Pa;

[0017] The pressing temperature is as follows: from room temperature (23℃) to 400℃ at a rate of less than 15℃ / min, and held at 400℃ for 30 minutes; then from 400℃ to 660℃-750℃ at a rate of 10℃ / min, and held at 660℃-750℃ for 75-150 minutes; then from 725℃ to 400℃ at a rate of 10℃ / min, and then cooled to room temperature in the furnace from 400℃.

[0018] The pressure is as follows: 15 minutes before reaching 725℃, a uniaxial pressure of 20 MPa is applied at a rate of approximately 1.3 MPa / min.

[0019] As a preferred embodiment of the present invention: the honeycomb core substrate is made of L-2Y aluminum alloy, and each cell is a regular hexagonal cell with a cell thickness of 14mm, a cell side length of 4mm, and a cell wall thickness of 0.04mm, which serves as a support and shear resistance.

[0020] As a preferred embodiment of the present invention: the lightweight ablation material layer is made of phenolic resin aerogel ablation material with a thickness of 2 mm to 4 mm; the lightweight thermal insulation material layer is made of alumina aerogel thermal insulation material with a thickness of 10 mm to 12 mm.

[0021] As a preferred embodiment of the present invention, both the lightweight ablation material layer and the lightweight thermal insulation material layer are filled into the honeycomb core matrix by an aerogel curing molding process.

[0022] As a preferred embodiment of the present invention, the aluminum alloy skin is made of ALCLAD-2024 aluminum alloy material.

[0023] By adopting the above technical solution, the present invention has the following beneficial effects:

[0024] This invention proposes an integrated honeycomb sandwich structure resistant to high-energy laser ablation. Compared to the original aluminum alloy skin structure, the aluminum / graphite / aluminum composite skin adds a high-reflectivity layer and a high-conductivity layer. This design efficiently reflects laser irradiation, reducing the total heat absorption. Furthermore, it enables rapid in-plane heat dissipation, improving the structure's conductivity, reducing the back surface temperature, and preventing localized structural damage. In this invention, lightweight ablation material and lightweight thermal insulation material are filled inside the original aluminum alloy honeycomb core, utilizing the characteristics of the cell, improving the structure's ablation resistance and increasing its breakdown time. This invention enhances the laser resistance of the honeycomb sandwich structure while maintaining lightweight design.

[0025] The aluminum / graphite / aluminum composite skin of this invention is prepared using a vacuum hot-pressing process. This process, with sufficient hot-pressing time and pressure, ensures a full interfacial reaction between the graphite and aluminum materials during preparation, generating a certain amount of Al2O3, thereby enhancing the interfacial bonding ability. Furthermore, because the vacuum hot-pressing process allows for strict control of the hot-pressing temperature, it ensures full bonding between the two materials while avoiding excessive interfacial reaction due to excessive temperature, thus preventing the formation of too much brittle Al2O3 and increased interfacial brittleness.

[0026] This invention involves in-situ infusion and curing of lightweight ablation and insulation materials within a honeycomb core, ensuring a strong bond between the filler material and the honeycomb core layer. This avoids the drawbacks of pre-preparing the ablation and insulation materials, followed by mechanical cutting and then filling them into the honeycomb core, which results in numerous voids between the filler material and the honeycomb core wall, thus affecting heat transfer and reducing the material's insulation capacity.

[0027] This invention is scientifically and rationally designed, and safe and convenient to prepare. By using an aluminum / graphite / aluminum composite material skin, a honeycomb core filled with lightweight ablation and heat insulation materials, and an aluminum alloy skin, the ablation resistance of the integrated honeycomb sandwich structure can be significantly enhanced while meeting the design requirements of lightweight structure. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of an integrated honeycomb sandwich structure resistant to high-energy laser ablation according to one embodiment of the present invention;

[0030] Figure 2 This is an exploded view of an integrated honeycomb sandwich structure resistant to high-energy laser ablation according to one embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram of an aluminum / graphite / aluminum composite material skin according to one embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of a honeycomb core filled with lightweight ablation and heat insulation materials according to one embodiment of the present invention.

[0033] Figure 5 This is a schematic diagram of an aluminum alloy skin structure according to one embodiment of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The present invention will be further explained below with reference to specific embodiments.

[0036] like Figure 1As shown, this embodiment provides an integrated honeycomb sandwich structure resistant to high-energy laser ablation, which includes a composite material skin 1, a honeycomb core 2 containing lightweight ablation material and lightweight heat insulation material, and an aluminum alloy skin 3.

[0037] like Figure 2 As shown, the composite material skin 1, as the first layer of the integrated honeycomb sandwich structure, includes a high reflectivity layer 11, a high conductivity layer 12, and an aluminum alloy layer 13.

[0038] The high reflectivity layer 11 is an aluminum alloy layer made of ALCLAD2024-T3. It is located on the outermost layer of the entire structure and is the first layer of the composite material skin 1. It contacts the high conductivity layer 12 inside the high reflectivity layer 11.

[0039] The high conductivity layer 12 is a graphite film layer made of a high thermal conductivity graphite film material with a thermal conductivity of 800 W / (m·K). It is the second layer of the composite material skin 1, with the outer side in contact with the high reflectivity layer 11 and the inner side in contact with the aluminum alloy layer 13. The thickness of the high conductivity layer 12 is 0.1 mm, and the thickness of the aluminum alloy layer 13 is 0.2 mm.

[0040] The high reflectivity layer 11, the high conductivity layer 12, and the aluminum alloy layer 13 are pressed together under high temperature and high pressure in a vacuum environment. The process parameters for this high temperature and high pressure pressing under vacuum include:

[0041] Vacuum level: less than 1×10 -3 Pa (preferably 5~9×10) -3 Pa);

[0042] The pressing temperature is as follows: from room temperature (23°C) to 400°C at a rate of less than 15°C / min (preferably 10°C / min), and held at 400°C for 30 min; then from 400°C to 660-750°C (preferably 725°C) at a rate of 10°C / min, and held at 660-750°C (preferably 725°C) for 75-150 min (preferably 100 min); then from 725°C to 400°C at a rate of 10°C / min, and then cooled to room temperature in the furnace from 400°C.

[0043] The pressure is as follows: 15 minutes before reaching 725℃, a uniaxial pressure of 20 MPa is applied at a rate of approximately 1.3 MPa / min.

[0044] The aluminum alloy layer 13 is the third layer of the composite material skin 1. It is in contact with the high conductivity layer 12 on the outside and the honeycomb core 2 filled with lightweight ablation material and heat insulation material on the inside.

[0045] like Figure 3As shown, the honeycomb core 2, which is filled with lightweight ablation material and thermal insulation material, includes a honeycomb core substrate 21, a lightweight ablation material layer 22, and a lightweight thermal insulation material layer 23.

[0046] The composite material skin 1 and the honeycomb core 2 are connected together by high-temperature adhesive curing.

[0047] The honeycomb core substrate 21 is made of aluminum alloy L-2Y. Each cell is a regular hexagonal cell with a thickness of 14 mm (14 mm is the preferred thickness, determined by the thickness of the entire honeycomb sandwich structure). The cell side length is 4 mm, and the cell wall thickness is 0.04 mm, providing support and shear resistance. The thickness of the honeycomb sandwich structure of the present invention can be selected from 10 mm, 15 mm, and 20 mm. Since the composite material skin (1) is 0.5 mm, the thickness of each cell can be selected from 9 mm, 14 mm, or 19 mm.

[0048] The lightweight ablation material layer 22 includes a phenolic aerogel ablation material 221, with a preferred thickness of 2 mm (the range of 2 mm to 4 mm is feasible according to the requirements of lightweighting). It is cured into the aluminum alloy honeycomb core 21 by a pouring and curing molding process to enhance the ablation resistance of the matrix material. The pouring and curing molding process is as follows: the sol for preparing aerogel is directly poured into the cell of the honeycomb core 2, allowing it to undergo a chemical reaction in the cell to form a solid gel network. The specific process is as follows: ① Pouring: the precursor solution of aerogel is injected into the cell of the honeycomb core matrix 21 to ensure that each cell is fully filled; ② Gel: the solution is left to stand in the cell of the honeycomb core matrix 21, and a polymerization reaction occurs to form a solid gel, which is tightly bonded to the cell wall of the honeycomb core matrix (21). This is the curing process; ③ Post-treatment: after the gel is formed, aging, solvent replacement and drying are required to form a complete aerogel structure and avoid cracking and shrinkage.

[0049] The lightweight thermal insulation material layer 23 includes an alumina aerogel thermal insulation material 231, with a preferred thickness of 12 mm (the range of 10 mm to 12 mm is feasible according to the requirements of lightweighting). It is cured into the aluminum alloy honeycomb core substrate 21 by a pouring and curing process, with the outer side in contact with the lightweight ablation material layer 22 and the inner side in contact with the aluminum alloy skin 3 of the integrated honeycomb sandwich structure.

[0050] The aluminum alloy skin 3 is made of ALCLAD-2024 aluminum alloy and serves as the lower skin of the integrated honeycomb sandwich structure, supporting and fixing the honeycomb core 2. The aluminum alloy skin 3 and the honeycomb core 2 are bonded together using adhesive. The adhesive used is J-47 solid adhesive, which requires high-temperature curing to complete the bonding. This high-temperature curing process ensures a vacuum environment with an ambient pressure of 0.1 MPa. The specific process is as follows: first, the temperature is increased from room temperature (23°C) to 130°C at a rate of 1°C / min; then, it is held at 130°C for 150 minutes; finally, it is cooled back to room temperature at a rate of 1°C / min to complete the bonding process.

[0051] This invention is scientifically and rationally designed, and safe and convenient to prepare. By using an aluminum / graphite / aluminum composite material skin, a honeycomb core filled with lightweight ablation and heat insulation materials, and an aluminum alloy skin, the ablation resistance of the integrated honeycomb sandwich structure can be significantly enhanced while meeting the design requirements of lightweight structure.

[0052] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated honeycomb sandwich structure resistant to high-energy laser ablation, characterized in that: The honeycomb sandwich structure includes a honeycomb core (2), a composite material skin (1) covering the front side of the honeycomb core (2), and an aluminum alloy skin (3) covering the back side of the honeycomb core (2). The composite material skin (1) includes an outermost high reflectivity layer (11), a middle high conductivity layer (12), and an innermost aluminum alloy layer (13). The honeycomb core (2) is a honeycomb core filled with lightweight ablation material and heat insulation material, which includes a honeycomb core substrate (21), a lightweight ablation material layer (22) covering the front side of the honeycomb core substrate (21) and in contact with the back side of the aluminum alloy layer (13), and a lightweight heat insulation material layer (23) covering the back side of the honeycomb core substrate (21). The aluminum alloy skin (3) is in contact with the back side of the lightweight thermal insulation material layer (23).

2. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1, characterized in that: The composite material skin (1) and the honeycomb core (2) are connected together by high-temperature adhesive curing; the aluminum alloy skin (3) and the honeycomb core (2) are bonded together by adhesive.

3. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1, characterized in that: The high reflectivity layer (11) is an aluminum alloy layer, and the material is ALCLAD2024-T3; The high conductivity layer (12) is made of a high thermal conductivity graphite film material with a thermal conductivity of 800 W / (m·K), and its front side is in contact with the back side of the high reflectivity layer (11). The front side of the aluminum alloy layer (13) is in contact with the back side of the high conductivity layer (12).

4. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1, characterized in that: The thickness of the high conductivity layer (12) is 0.1 mm; the thickness of the aluminum alloy layer (13) is 0.2 mm.

5. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1 or 2, characterized in that: The high reflectivity layer (11), the high conductivity layer (12), and the aluminum alloy layer (13) are pressed together under high temperature and high pressure in a vacuum environment to form the composite material skin (1).

6. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 5, characterized in that, The process parameters for pressing under high temperature and high pressure in a vacuum environment include: Vacuum level: less than 1×10 -3 Pa; The pressing temperature is as follows: from room temperature (23℃) to 400℃ at a rate of less than 15℃ / min, and held at 400℃ for 30 minutes; then from 400℃ to 660℃-750℃ at a rate of 10℃ / min, and held at 660℃-750℃ for 75-150 minutes; then from 725℃ to 400℃ at a rate of 10℃ / min, and then cooled to room temperature in the furnace from 400℃. The pressure is as follows: 15 minutes before reaching 725℃, a uniaxial pressure of 20 MPa is applied at a rate of approximately 1.3 MPa / min.

7. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1, characterized in that: The honeycomb core substrate (21) is made of L-2Y aluminum alloy. Each cell is a regular hexagonal cell with a cell thickness of 14mm, a cell side length of 4mm, and a cell wall thickness of 0.04mm, which serves as a support and shear resistance.

8. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1, characterized in that: The lightweight ablation material layer (22) is made of phenolic resin aerogel ablation material with a thickness of 2 mm to 4 mm; The lightweight thermal insulation material layer (23) is made of 10 mm to 12 mm thick alumina aerogel thermal insulation material.

9. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1, characterized in that: Both the lightweight ablation material layer (22) and the lightweight thermal insulation material layer (23) are filled into the honeycomb core matrix (21) by an aerogel curing molding process.

10. The integrated honeycomb sandwich structure resistant to high-energy laser ablation as described in claim 1, characterized in that: The aluminum alloy skin (3) is made of ALCLAD-2024 aluminum alloy material.

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