Modular filling combined honeycomb and preparation method and application thereof

Abstract

The invention discloses a modular filling combined honeycomb and a preparation method and application thereof, and relates to the technical field of wave-absorbing materials. The modular filling combined honeycomb comprises a plurality of honeycomb holes filled with functional materials, the functional materials in the honeycomb holes are the same or different, and each functional material comprises a foaming material. According to the modular filling combined honeycomb, the wave-absorbing structure design can be carried out on the single honeycomb hole as required; the service life of the honeycomb is prolonged, the wave absorbing effect of the honeycomb is improved, the application field of the honeycomb is widened, and the honeycomb is particularly applied to aviation stealth fighters.

Description

Technical Field

[0001] The present application relates to the technical field of microwave absorbing materials, and more particularly, to a modular filling combined honeycomb, its preparation method and application. Background Art

[0002] With the improvement of military radar detection technology, the detection and analysis capabilities for military aircraft are getting stronger and stronger. In order to enhance the battlefield environment survival adaptability of special aircraft such as fighter jets, bombers, and electromagnetic aircraft, it is necessary to design the aircraft's external shape during the early stage of aircraft manufacturing, making its surface as smooth, flat, and gapless as possible to generate electromagnetic echoes. At the same time, it is necessary to structurally integrate the parts with large electromagnetic wave reflections with stealth microwave absorbing materials, so that the incident electromagnetic waves can enter the aircraft's stealth structure interior to the greatest extent. Through the material's functional and structural characteristics, the electromagnetic wave energy inside the material can be effectively attenuated, thus ensuring the safe flight of the aircraft.

[0003] Currently, due to structural mechanics and weight requirements, the aircraft structure mostly uses a honeycomb (PMI foam) sandwich structure with light weight, high specific strength and specific stiffness, strong impact resistance and fatigue resistance, and strong designability to make stealth materials. The performance structure of traditional microwave absorbing honeycombs is single. The process of impregnating and spraying microwave absorbing slurries on the honeycomb can only achieve gradual changes in certain areas. Due to process problems, the adhesion amount of the microwave absorbing slurry in different parts of the honeycomb is different, resulting in deformation of the honeycomb cell lattice and poor structural stability and shear resistance of the subsequent honeycomb components. In order to better improve the microwave absorbing effect, a complex laminated structure composed of resistor sheets + honeycombs + resistor sheets + honeycombs stacked along the T direction of the honeycomb is usually constructed, but the bonding force between its structural layers is poor and it is easy to delaminate, seriously affecting the overall structural strength of the component. Summary of the Invention

[0004] The main purpose of the present application is to provide a modular filling combined honeycomb, its preparation method and application, so as to solve the problem that the current stealth materials have insufficient structural stability and it is difficult to have both high microwave absorbing performance and high mechanical properties.

[0005] To achieve the above object, according to the first aspect of the present application, there is provided a modular filling combined honeycomb, which includes a plurality of honeycomb cells filled with functional materials, and the functional materials in each honeycomb cell are the same or different; and each functional material includes a foaming material.

[0006] Further, each functional material independently includes at least one of a first functional layer, a second functional layer, a third functional layer, a fourth functional layer, a fifth functional layer, a sixth functional layer, a seventh functional layer, and an eighth functional layer; when the functional material includes multiple functional layers, each functional layer is stacked along the T direction of the modular filling combined honeycomb to form the functional material; the thickness of each functional layer is independently 0.05 - 1 times the height of the honeycomb cell.

[0007] Furthermore, the material of the first functional layer is a high-resistance loss foaming material with a sheet resistance of 50 - 100 kΩ / □, and its composition does not include hollow wave-absorbing microspheres;

[0008] Furthermore, the material of the second functional layer is a medium-resistance loss foaming material with a sheet resistance of 10 - 50 kΩ / □, and its composition does not include hollow wave-absorbing microspheres;

[0009] Furthermore, the material of the third functional layer is a low-resistance loss foaming material with a sheet resistance of 5 - 10 kΩ / □, and its composition does not include hollow wave-absorbing microspheres;

[0010] Furthermore, the material of the fourth functional layer is an extremely low-resistance loss foaming material with a sheet resistance of 1 - 5 kΩ / □, and its composition does not include hollow wave-absorbing microspheres;

[0011] Furthermore, the material of the fifth functional layer is a high-magnetic loss foaming material with a magnetic permeability of 3 - 5 H / m;

[0012] Furthermore, the material of the sixth functional layer is a low-resistance loss three-dimensional thin-walled hollow wave-absorbing material with a sheet resistance of 5 - 10 kΩ / □, and its composition includes hollow wave-absorbing microspheres;

[0013] Furthermore, the material of the seventh functional layer is a medium-resistance loss three-dimensional thin-walled hollow wave-absorbing material with a sheet resistance of 10 - 50 kΩ / □, and its composition includes hollow wave-absorbing microspheres;

[0014] Furthermore, the material of the eighth functional layer is a high-resistance loss three-dimensional thin-walled hollow wave-absorbing material with a sheet resistance of 50 - 100 kΩ / □, and its composition includes hollow wave-absorbing microspheres.

[0015] Furthermore, along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are cyclically filled in each honeycomb hole in sequence: the first functional material, the second functional material, the third functional material, the fourth functional material, the third functional material, the second functional material;

[0016] The first functional material is composed of the first functional layer;

[0017] The second functional material: The second functional layer and the first functional layer are stacked on top of each other from bottom to top;

[0018] The third functional material: The third functional layer, the second functional layer, and the first functional layer are stacked on top of each other from bottom to top;

[0019] The fourth functional material: The third functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked on top of each other from bottom to top;

[0020] Among them, the thickness of the first functional layer is 0.05 - 0.15 times the height of the honeycomb holes, the thickness of the second functional layer is 0.15 - 0.2 times the height of the honeycomb holes, and the thickness of the third functional layer is 0.15 - 0.25 times the height of the honeycomb holes.

[0021] Further, along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are filled in each honeycomb hole in sequence:

[0022] The fifth functional material: The fifth functional layer, the fourth functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0023] The fifth functional material;

[0024] The sixth functional material: The fifth functional layer, the third functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0025] The seventh functional material: The fifth functional layer, the second functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0026] The eighth functional material: The fifth functional layer, the first functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0027] Among them, the thickness of the first functional layer is 0.7 - 0.9 times the height of the honeycomb holes, the thickness of the second functional layer is 0.7 - 0.9 times the height of the honeycomb holes, the thickness of the third functional layer is 0.7 - 0.9 times the height of the honeycomb holes, the thickness of the fourth functional layer is 0.7 - 0.9 times the height of the honeycomb holes, and the thickness of the fifth functional layer is 0.05 - 0.15 times the height of the honeycomb holes.

[0028] Further, along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are filled in each honeycomb hole:

[0029] The ninth functional material: The fourth functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top;

[0030] Among them, the thickness of the first functional layer is 0.05 - 0.15 times the height of the honeycomb holes, the thickness of the second functional layer is 0.1 - 0.2 times the height of the honeycomb holes, the thickness of the third functional layer is 0.2 - 0.3 times the height of the honeycomb holes, and the thickness of the fourth functional layer is 0.3 - 0.5 times the height of the honeycomb holes.

[0031] Further, along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are filled in each honeycomb hole:

[0032] The tenth functional material: The fourth functional layer, the sixth functional layer, the seventh functional layer, and the eighth functional layer are stacked in sequence from bottom to top;

[0033] Among them, the thickness of the fourth functional layer is 0.2 to 0.3 times the height of the honeycomb cell, the thickness of the sixth functional layer is 0.2 to 0.4 times the height of the honeycomb cell, the thickness of the seventh functional layer is 0.2 to 0.3 times the height of the honeycomb cell, and the thickness of the eighth functional layer is 0.1 to 0.2 times the height of the honeycomb cell.

[0034] The sixth functional layer, the seventh functional layer, and the eighth functional layer each independently include at least one of graded A balls with a diameter of 1 to 1.5 mm and graded B balls with a diameter of 2.2 to 3 mm. The A balls and B balls are only used to distinguish the diameters and do not represent specific types. The A balls and B balls in the layers of the sixth functional layer, the seventh functional layer, and the eighth functional layer can be assembled according to the stealth design. For example, the sixth functional layer includes A balls and the seventh functional layer includes B balls, etc.

[0035] Further, along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are filled in each honeycomb cell:

[0036] The eleventh functional material: The first functional layer, the second functional layer, the third functional layer, the fourth functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top;

[0037] Among them, the thickness of the first functional layer is 0.05 to 0.1 times the height of the honeycomb cell, the thickness of the second foaming layer is 0.1 to 0.15 times the height of the honeycomb cell, the thickness of the third foaming layer is 0.1 to 0.15 times the height of the honeycomb cell, and the thickness of the fourth foaming layer is 0.2 to 0.4 times the height of the honeycomb cell.

[0038] According to the second aspect of the present application, a method for preparing a modular filling combined honeycomb is provided, including the following steps:

[0039] S1. Prepare different types of foaming preforms and thin-walled hollow wave-absorbing preforms to obtain high-resistance-loss foaming preforms, medium-resistance-loss foaming preforms, low-resistance-loss foaming preforms, extremely low-resistance-loss foaming preforms, high-magnetic-loss foaming preforms, low-resistance-loss three-dimensional thin-walled hollow wave-absorbing preforms, medium-resistance-loss three-dimensional thin-walled hollow wave-absorbing preforms, and high-resistance-loss three-dimensional thin-walled hollow wave-absorbing preforms;

[0040] S2. Respectively cut different types of foaming preforms to obtain different cylindrical strips;

[0041] S3. Cut different cylindrical strips according to the required thickness to obtain the same or different foaming preform blocks;

[0042] S4. Stack the foaming preform blocks or the foaming preform blocks and the thin-walled hollow wave-absorbing preforms in sequence from bottom to top in different honeycomb cells of the modular filling combined honeycomb to obtain a honeycomb semi-finished product;

[0043] S4. Cure the honeycomb semi-finished product to obtain a modular filling combined honeycomb.

[0044] Among them, the foamed preform block is cured into a foamed material, and the thin-walled hollow wave-absorbing preform is cured into a thin-walled hollow wave-absorbing material.

[0045] Furthermore, the diameter of the cylindrical bar is 50% - 80% of the diameter of the honeycomb hole.

[0046] According to the third aspect of the present application, there is provided an application of the modular filling combined honeycomb of the first aspect of the present application or the modular filling combined honeycomb prepared by the preparation method of the second aspect of the present application in a stealth device.

[0047] By applying the modular filling combined honeycomb of the present application, the design of a single honeycomb hole can be carried out to achieve a more precise 3D wave-absorbing interface design, improve the wave-absorbing performance of the stealth device, and enhance its battlefield survival ability. In addition, compared with the wave-absorbing honeycomb prepared by traditional impregnation and spraying of wave-absorbing slurries, by designing a single honeycomb hole and filling with a foamed material, it helps to improve its structural stability. Description of the Drawings

[0048] Figure 1 It is a schematic structural diagram of the modular filling combined honeycomb in Embodiment 1 (A) and Embodiment 2 (B) of the present application;

[0049] Figure 2 It is a schematic structural diagram of the modular filling combined honeycomb in Embodiment 3 (C), Embodiment 4 (D), and Embodiment 5 (E) of the present application;

[0050] Figure 3 It is a schematic structural diagram of the modular filling combined honeycomb in Embodiment 6 of the present application;

[0051] The following reference numerals exist in the above drawings:

[0052] 1. Honeycomb matrix; 2. First functional layer; 3. Second functional layer; 4. Third functional layer; 5. Fourth functional layer; 6. Fifth functional layer; 7. Sixth functional layer; 8. Seventh functional layer; 9. Eighth functional layer. Detailed Embodiments

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0054] As described in the background art of this application, there is a problem of poor stability of the wave-absorbing honeycomb structure in the prior art. To solve the above technical problems, in a typical embodiment of this application, a modular filling combined honeycomb is provided. The modular filling combined honeycomb includes a plurality of honeycomb holes filled with functional materials. The functional materials in each honeycomb hole are the same or different, and each functional material includes a foaming material.

[0055] By filling a single honeycomb hole, a more precise wave-absorbing interface design can be achieved, and the quality of each part of the honeycomb can be precisely controlled through filling, so that it has good mechanical strength. In addition, the foaming material is light in weight, which is beneficial to the preparation of lightweight stealth devices. And compared with the traditional process of impregnating and spraying wave-absorbing slurries, it can avoid phenomena such as shrinkage and deformation of the honeycomb cell lattice after curing caused by different amounts of slurry attachment in different parts of the honeycomb, and significantly improve the structural stability of the honeycomb.

[0056] In some embodiments, each functional material independently includes at least one of a first functional layer, a second functional layer, a third functional layer, a fourth functional layer, a fifth functional layer, a sixth functional layer, a seventh functional layer, and an eighth functional layer. When the functional material includes multiple functional layers, each functional layer is stacked along the T direction of the modular filling combined honeycomb to form the functional material. The thickness of each functional layer is independently 0.05 to 1 times the height of the honeycomb hole.

[0057] In some embodiments, the material of the first functional layer is a high-resistance loss type foaming material, its sheet resistance is 50 to 100 kΩ / □, and its composition does not include hollow wave-absorbing microspheres.

[0058] The material of the second functional layer is a medium-resistance loss type foaming material, its sheet resistance is 10 to 50 kΩ / □, and its composition does not include hollow wave-absorbing microspheres.

[0059] The material of the third functional layer is a low-resistance loss type foaming material, its sheet resistance is 5 to 10 kΩ / □, and its composition does not include hollow wave-absorbing microspheres.

[0060] The material of the fourth functional layer is an extremely low-resistance loss type foaming material, its sheet resistance is 1 to 5 kΩ / □, and its composition does not include hollow wave-absorbing microspheres.

[0061] The material of the fifth functional layer is a high-magnetic loss type foaming material, its magnetic permeability is 3 to 5 H / m, and its absorption band is the L to S band.

[0062] The material of the sixth functional layer is a low-resistance loss type three-dimensional thin-walled hollow wave-absorbing material, its sheet resistance is 5 to 10 kΩ / □, and its composition includes hollow wave-absorbing microspheres.

[0063] The material of the seventh functional layer is a medium-resistance loss type three-dimensional thin-walled hollow wave-absorbing material, with a sheet resistance of 10 to 50 kΩ / sq, and its composition includes hollow wave-absorbing microspheres;

[0064] The material of the eighth functional layer is a high-resistance loss type three-dimensional thin-walled hollow wave-absorbing material, with a sheet resistance of 50 to 100 kΩ / sq, and its composition includes hollow wave-absorbing microspheres.

[0065] By filling the honeycomb holes with functional materials (at least one of foaming materials and thin-walled hollow wave-absorbing materials), on the one hand, a lightweight stealth structure can be obtained, which helps to realize the lightweight of stealth devices; on the other hand, compared with the honeycomb stealth structure prepared by impregnating and spraying wave-absorbing slurries, its structural stability is high, and the honeycomb cell lattice will not deform due to different amounts of slurry attachment, and then the honeycomb will crack, affecting its structural stability. In addition, the traditional stealth structure has a relatively rough wave-absorbing interface because the production process is designed on a whole wave-absorbing honeycomb blank, resulting in poor wave-absorbing performance. The modular filling combined honeycomb described in this application can be accurately designed for a single honeycomb hole, which helps to improve the wave-absorbing performance of the honeycomb. Especially, when the interface of the combined surface of the built-in high-frequency antenna in the component is treated with wave-absorbing, it can meet the antenna stealth requirements without affecting the antenna radiation gain. The first to eighth functional layers provided in this application can achieve multi-band and wide-band absorption of electromagnetic waves, effectively improving the electromagnetic stealth performance of stealth devices, and are applicable to fields such as national defense, aerospace, and aviation, which have important value for improving the concealment and battlefield survival ability of aircraft, ships, ground vehicles, etc. Further, each functional material includes at least one of the first functional layer, the second functional layer, the third functional layer, the fourth functional layer, and the fifth functional layer. Through the above optimization, it helps to further improve the structural stability of the modular filling combined honeycomb.

[0066] In this application, the materials (foaming materials) of the first to fifth functional layers are obtained by mixing wave-absorbing materials, thermoplastic elastomers, foaming agents, and additives, first preparing a foaming preform, and then curing; the materials (thin-walled hollow wave-absorbing materials) of the sixth to eighth functional layers are obtained by mixing wave-absorbing materials, thin-walled hollow bodies, and additives, first preparing a thin-walled hollow wave-absorbing preform, filling the foaming preform or the thin-walled hollow wave-absorbing preform into the honeycomb holes, and then curing and heating the honeycomb.

[0067] Specifically, the high-resistance loss type functional material is obtained by heating a high-resistance loss type foaming preform, and the high-resistance loss type foaming preform includes the following components in parts by weight: 50 to 100 parts of thermoplastic polyester elastomer (TPEE), 3 to 10 parts of carbon-based wave-absorbing material, 0.1 to 2 parts of carbon-based short fiber filaments, 0.5 to 10 parts of foaming agent, 0.03 to 3 parts of vulcanizing agent, 0.05 to 0.5 parts of antioxidant, 0.5 to 4 parts of coupling agent, and 0.2 to 4 parts of dispersant.

[0068] The medium resistance loss type functional material is obtained by heating a medium resistance loss type foamed preform. The difference between the composition of the medium resistance loss type foamed preform and that of the high resistance loss type foamed preform is only that the weight portion of the carbon-based wave-absorbing material is 6-13 parts and the weight portion of the carbon-based short fiber filaments is 1-3 parts.

[0069] The low resistance loss type functional material is obtained by heating a low resistance loss type foamed preform. The difference between the composition of the low resistance loss type foamed preform and that of the high resistance loss type foamed preform is only that the weight portion of the carbon-based wave-absorbing material is 9-16 parts and the weight portion of the carbon-based short fiber filaments is 2-4 parts.

[0070] The extremely low resistance loss type functional material is obtained by heating an extremely low resistance loss type foamed preform. The difference between the composition of the extremely low resistance loss type foamed preform and that of the high resistance loss type foamed preform is only that the weight portion of the carbon-based wave-absorbing material is 12-20 parts and the weight portion of the carbon-based short fiber filaments is 3-5 parts.

[0071] The high magnetic loss type functional material is obtained by heating a high magnetic loss type foamed preform. The difference between the composition of the high magnetic loss type foamed preform and that of the high resistance loss type foamed preform is only that it does not contain the carbon-based wave-absorbing material and the carbon-based short fiber filaments, and further includes 20-40 parts of a magnetic wave-absorbing material and 5-15 parts of magnetic short fiber filaments.

[0072] The low resistance loss type three-dimensional thin-walled hollow wave-absorbing material is obtained by heating a low resistance loss type three-dimensional thin-walled hollow wave-absorbing preform. The low resistance loss type three-dimensional thin-walled hollow wave-absorbing preform includes the following components in weight portions: 12-18 parts of a carbon-based wave-absorbing material, and 70-90 parts of alumina hollow spheres; the alumina hollow spheres are alumina hollow spheres A, and the diameter of the alumina hollow spheres A is 1-1.5 mm.

[0073] The medium resistance loss type three-dimensional thin-walled hollow wave-absorbing material is obtained by heating a medium resistance loss type three-dimensional thin-walled hollow wave-absorbing preform. The difference between the composition of the medium resistance loss type three-dimensional thin-walled hollow wave-absorbing preform and that of the low resistance loss type three-dimensional thin-walled hollow wave-absorbing preform is only that the weight portion of the carbon-based wave-absorbing material is 6-12 parts; among them, the alumina hollow spheres are a mixture of alumina hollow spheres A and alumina hollow spheres B, and the weight ratio of the alumina hollow spheres A to the alumina hollow spheres B is (20-40):(40-50), the diameter of the alumina hollow spheres A is 1-1.5 mm, and the diameter of the alumina hollow spheres B is 2.2-3 mm.

[0074] The high-resistance-loss three-dimensional thin-walled hollow wave-absorbing material is obtained by heating a high-resistance-loss three-dimensional thin-walled hollow wave-absorbing preform. The difference between the composition of the high-resistance-loss three-dimensional thin-walled hollow wave-absorbing preform and the composition of the low-resistance-loss three-dimensional thin-walled hollow wave-absorbing preform is only that the weight part of the carbon-based wave-absorbing material is 2-6 parts; among them, the alumina hollow sphere is alumina hollow sphere B, and the diameter of the alumina hollow sphere B is 2.2-3 mm.

[0075] Typical and non-limiting, in this application, the carbon-based wave-absorbing material includes at least one of graphene, carbon black, and carbon nanotubes; the carbon-based short fiber filaments include at least one of carbon fiber and silicon carbide fiber; the magnetic wave-absorbing material includes at least one of ferrite, carbonyl iron, and magnetic metal micropowder; the magnetic short fiber filaments include ferrite nanofibers, etc. The above materials all have good wave-absorbing properties. In addition, the foaming agent, vulcanizing agent, antioxidant, coupling agent, and dispersant can be common materials; for example, the foaming agent can be thermally expandable foaming microspheres, specifically at least one of 200DU35, 220DU3, etc. of POLYCHEN Company in the United States; the vulcanizing agent can be triallyl isocyanurate (TAIC); the antioxidant can be tricalcium phosphate (TCP); the coupling agent can be dichlorosilane; the dispersant can be stearic acid. The above components are easy to obtain and have good processing properties.

[0076] In some embodiments, along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are sequentially and circularly filled in each honeycomb hole: the first functional material, the second functional material, the third functional material, the fourth functional material, the third functional material, the second functional material;

[0077] The first functional material is composed of a first functional layer;

[0078] The second functional material: a second functional layer and a first functional layer are sequentially stacked from bottom to top;

[0079] The third functional material: a third functional layer, a second functional layer, and a first functional layer are sequentially stacked from bottom to top;

[0080] The fourth functional material: a third functional layer, a third functional layer, a second functional layer, and a first functional layer are sequentially stacked from bottom to top;

[0081] Among them, the thickness of the first functional layer is 0.05-0.15 times the height of the honeycomb hole, the thickness of the second functional layer is 0.15-0.2 times the height of the honeycomb hole, and the thickness of the third functional layer is 0.15-0.25 times the height of the honeycomb hole.

[0082] In the above embodiments, the modular filling combined honeycomb has a serrated mirror deflection and scattering structure along the T direction, combined with impedance gradient; by designing the structure of the modular filling combined honeycomb as above, on the one hand, the foaming materials in the honeycomb holes can be hierarchically arranged, so that the modular filling combined honeycomb has different electromagnetic absorption capabilities, realizing the effective absorption and deflection of electromagnetic waves in a wide frequency band, thereby reducing the radar cross section (RCS) of stealth devices such as aircraft; on the other hand, unnecessary structural weight increase can be avoided, the usage amount of materials can be reduced, and the shear resistance of the honeycomb holes can be enhanced, improving its structural stability.

[0083] In some embodiments, along any direction perpendicular to the T direction of the modular filling combined honeycomb, the following foaming materials are filled in each honeycomb hole in sequence:

[0084] The fifth functional material: the fifth functional layer, the fourth functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0085] The fifth functional material;

[0086] The sixth functional material: the fifth functional layer, the third functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0087] The seventh functional material: the fifth functional layer, the second functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0088] The eighth functional material: the fifth functional layer, the first functional layer, and the fifth functional layer are stacked in sequence from bottom to top;

[0089] Among them, the thickness of the first functional layer is 0.7 - 0.9 times the height of the honeycomb hole, the thickness of the second functional layer is 0.7 - 0.9 times the height of the honeycomb hole, the thickness of the third functional layer is 0.7 - 0.9 times the height of the honeycomb hole, the thickness of the fourth functional layer is 0.7 - 0.9 times the height of the honeycomb hole, and the thickness of the fifth functional layer is 0.05 - 0.15 times the height of the honeycomb hole.

[0090] By combining the impedance gradient electromagnetic absorption structure and the low-frequency mirror reflection layer with high magnetic loss on the end face of the honeycomb in the T direction, especially when detecting the radar on the side, the incident wave can enter the cavity effectively to the greatest extent, be absorbed inside the cavity, and reduce the formation of echo, which is suitable for the stealth structure treatment of the wing tips and the lateral side strips of the fuselage of fighter planes.

[0091] In some embodiments, along any direction perpendicular to the T direction of the modular filling combined honeycomb, the following functional materials are filled in each honeycomb hole:

[0092] The ninth functional material: the fourth functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top;

[0093] Among them, the thickness of the first functional layer is 0.05 to 0.15 times the height of the honeycomb holes, the thickness of the second functional layer is 0.1 to 0.2 times the height of the honeycomb holes, the thickness of the third functional layer is 0.2 to 0.3 times the height of the honeycomb holes, and the thickness of the fourth functional layer is 0.3 to 0.5 times the height of the honeycomb holes.

[0094] The above modular filling combined honeycomb T-direction is an impedance-gradient electromagnetic absorption structure, which is suitable for stealth treatment of leading-edge parts such as the leading edge of the wing and the leading edge of the tail wing of a fighter plane. The direction of absorbing the incident wave is approximately the same as the force direction, with good wave absorption performance, high structural stability, and a long service life.

[0095] In some embodiments, along any direction perpendicular to the T-direction of the modular filling combined honeycomb, the following functional materials are filled in each honeycomb hole:

[0096] The tenth functional material: The fourth functional layer, the sixth functional layer, the seventh functional layer, and the eighth functional layer are stacked in sequence from bottom to top;

[0097] Among them, the thickness of the fourth functional layer is 0.2 to 0.3 times the height of the honeycomb holes, the thickness of the sixth functional layer is 0.2 to 0.4 times the height of the honeycomb holes, the thickness of the seventh functional layer is 0.2 to 0.3 times the height of the honeycomb holes, and the thickness of the eighth functional layer is 0.1 to 0.2 times the height of the honeycomb holes.

[0098] In the above embodiments, the ends of each honeycomb hole can be on the same horizontal plane or not on the same horizontal plane.

[0099] By setting an impedance-gradient electromagnetic absorption structure in the T-direction of the modular filling combined honeycomb and combining it with a three-dimensional hollow structure, the absorption interface can be any curved surface as the structure changes. This modular filling combined honeycomb is suitable for stealth treatment of parts with built-in high-frequency antennas such as the leading edge of the wing and the leading edge of the tail wing of a stealth fighter plane. At the same time, a more precise 3D wave absorption interface design can be carried out on the 3D honeycomb structure after machining, and the wave absorption effect of the wave absorption interface can be strengthened twice.

[0100] In some embodiments, along any direction perpendicular to the T-direction of the modular filling combined honeycomb, the following functional materials are filled in each honeycomb hole:

[0101] The eleventh functional material: The first functional layer, the second functional layer, the third functional layer, the fourth functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top;

[0102] Among them, the thickness of the first functional layer is 0.05 to 0.1 times the height of the honeycomb holes, the thickness of the second functional layer is 0.1 to 0.15 times the height of the honeycomb holes, the thickness of the third functional layer is 0.1 to 0.15 times the height of the honeycomb holes, and the thickness of the fourth functional layer is 0.2 to 0.4 times the height of the honeycomb holes.

[0103] In this embodiment, the modular filling combined honeycomb has a gradually varying impedance electromagnetic absorption structure in the T direction, which is suitable for absorbing incident waves from the upper and lower directions of the modular filling combined honeycomb. Since the aileron of the fighter plane is a rotatable structure that rotates up and down, the modular filling combined honeycomb in this embodiment is suitable for stealth treatment of the aileron of the fighter plane.

[0104] In another typical embodiment of the present application, a preparation method of a modular filling combined honeycomb is provided, including the following steps:

[0105] S1, Prepare different types of foamed preforms and thin-walled hollow wave-absorbing preforms to obtain high-resistance loss type foamed preforms, medium-resistance loss type foamed preforms, low-resistance loss type foamed preforms, extremely low-resistance loss type foamed preforms, high-magnetic loss type foamed preforms, low-resistance loss type three-dimensional thin-walled hollow wave-absorbing preforms, medium-resistance loss type three-dimensional thin-walled hollow wave-absorbing preforms, and high-resistance loss type three-dimensional thin-walled hollow wave-absorbing preforms;

[0106] S2, Cut different types of foamed preforms respectively to obtain different cylindrical bars;

[0107] S3, Cut different cylindrical bars according to the required thickness to obtain the same or different foamed preform blocks;

[0108] S4, Stack the foamed preform blocks, or the foamed preform blocks and the thin-walled hollow wave-absorbing preforms from bottom to top in different honeycomb holes of the modular filling combined honeycomb according to the design to obtain a honeycomb semi-finished product;

[0109] S4, Cure the honeycomb semi-finished product to obtain a modular filling combined honeycomb with single or multiple functional layers in the honeycomb holes.

[0110] In the above embodiments of the present application, by first preparing a foamed preform block and a thin-walled hollow absorbing preform with specific wave-absorbing properties, the wave-absorbing material in a single honeycomb cell can be regulated according to the wave-absorbing requirements of the stealth device, and appropriate preforms can be selected and stacked; by using the above method, an impedance-gradient electromagnetic absorption structure and other structures can be formed along the T-direction of the modular filling combined honeycomb or in the direction perpendicular to the T-direction of the modular filling combined honeycomb, which are applicable to multiple parts of the stealth device, help to efficiently absorb and convert the incident wave, and can significantly improve the stealth effect. In addition, by directly stacking the preform blocks in the honeycomb matrix, the above method can avoid the problem of poor stability of the honeycomb structure easily caused by traditional methods such as dipping and spraying, and help to extend the service life of the honeycomb. In addition, during the subsequent use process, if the wave-absorbing performance fails to meet the expectations, other foamed preforms can be filled and further cured; the honeycomb can be reprocessed, which can significantly reduce the production cost.

[0111] Typically but not limitedly, the preparation method of the foamed preform includes the following steps:

[0112] S11, putting the thermoplastic polyester elastomer into an oven for drying;

[0113] S12, adding the dried thermoplastic polyester elastomer into a mixer, stirring at 140-190 °C for 3-6 min, then adding an antioxidant, a coupling agent, and a dispersant respectively, and stirring for 3-6 min to obtain a first mixture;

[0114] S13, adding a wave-absorbing material into the mixer and stirring for 6-12 min to obtain a second mixture;

[0115] S14, turning on the open mill, initially setting the roll gap to 2-5 mm and the roll temperature to 130-180 °C, placing the second mixture on the open mill for plasticizing and then milling for 3-5 min, adding short fiber filaments in small amounts in multiple times and milling for 3-5 min, adjusting the roll gap to 1.5-2 mm, uniformly adding a foaming agent and milling for 3-5 min, and then adding a vulcanizing agent and milling for 5-10 min to obtain the foamed preform.

[0116] The foamed preform prepared by the above method has a certain mechanical strength and is suitable for preparing a modular filling combined honeycomb by the filling method.

[0117] In some embodiments, a cylindrical bar is cut into foamed preform blocks by a hot pressing and cutting method, and the hot pressing conditions are: 150-190 °C, 0.3-0.5 MPa. Under the above conditions, the flatness of hot pressing and cutting is high and the processing accuracy is high.

[0118] In some embodiments, the diameter of the cylindrical bar is 50%-80% of the diameter of the honeycomb cell.

[0119] Making the above-mentioned limitation on the diameter of the cylindrical bar can make the diameter of the foamed block after heating and curing match the diameter of the honeycomb holes, obtaining a modular filling combined honeycomb with a compact structure, improving the structural stability of the honeycomb, and further improving the service life of the honeycomb.

[0120] Typical but not limiting, the preparation method of the thin-walled hollow wave-absorbing preform is as follows: Add alumina hollow spheres to the wave-absorbing slurry (the base material is a carbon-based wave-absorbing material) for impregnation and mixing. The impregnation time is 1 - 3 minutes, then lift it with a wire mesh, control the liquid for 3 - 8 minutes, and then transfer it to a rotary screen box, rotate and dry it on the hot air surface for 5 - 15 minutes. To make the resistance value meet the requirements, the surface-dried product can be pre-cured at 100 - 150 °C for 1 - 2 hours, and then repeat the above steps until the resistance value meets the requirements, but the last time does not require pre-curing, so that the thin-walled hollow wave-absorbing preform can be finally cured and adhered in the honeycomb holes. The above method has a simple process and can evenly cover the wave-absorbing material on the outer wall of the alumina hollow spheres.

[0121] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0122] The materials used in the embodiments are as follows:

[0123] The honeycomb matrix is aramid honeycomb, with a pore diameter of 3.2 mm, a density of 64 kg / m 3 , and the T-direction dimension is 40 ± 1 mm.

[0124] The antioxidant is tricalcium phosphate; the coupling agent is dichlorosilane; the dispersant is stearic acid; the carbon-based wave-absorbing material is graphene; the carbon-based short fiber filament is carbon fiber; the foaming agent is 200DU35; the vulcanizing agent is triallyl isocyanurate; the magnetic wave-absorbing material is ferrite; the magnetic short fiber filament is ferrite nanofiber; the diameter of alumina hollow sphere A is 1 - 1.3 mm, and the wall thickness is 0.03 - 0.07 mm; the diameter of alumina hollow sphere B is 2.3 - 2.6 mm, and the wall thickness is 0.05 - 0.1 mm.

[0125] The preparation method of the high-resistance loss type foamed preform is as follows:

[0126] S11, Put the TPEE into the oven and dry it at 100 °C for 2 hours;

[0127] S12, Add 100 parts of the dried thermoplastic polyester elastomer to the internal mixer, stir at 160 °C for 5 minutes, control the stirring rate at 60 r / min, and then add 0.2 part of antioxidant, 1.8 parts of coupling agent, and 2.2 parts of dispersant respectively, and stir for 5 minutes to obtain the first mixture;

[0128] S13. Then, add 4.9 parts of carbon-based wave-absorbing material into the internal mixer and stir for 10 min to obtain the second mixture;

[0129] S14. Turn on the two-roll mill, initially set the roll gap to 3 mm and the roll temperature to 155 °C. Place the second mixture on the two-roll mill for plasticizing and then open mill for 5 min. Add 0.6 part of carbon-based short fiber filaments in small amounts in multiple batches and open mill for 5 min. Adjust the roll gap to 1.5 mm, evenly add 0.5 - 10 parts of blowing agent, open mill for 5 min, then add 0.5 part of vulcanizing agent and open mill for 5 - 10 min to obtain the foaming preform.

[0130] The preparation method of the medium resistance loss type foaming preform is only different from that of the high resistance loss type foaming preform in that: in S13, the weight part of the carbon-based wave-absorbing material is 7.8 parts, and the weight part of the carbon-based short fiber filaments is 1.5 parts.

[0131] The preparation method of the low resistance loss type foaming preform is only different from that of the high resistance loss type foaming preform in that: in S13, the weight part of the carbon-based wave-absorbing material is 12 parts, and the weight part of the carbon-based short fiber filaments is 2.6 parts.

[0132] The preparation method of the extremely low resistance loss type foaming preform is only different from that of the high resistance loss type foaming preform in that: in S13, the weight part of the carbon-based wave-absorbing material is 16 parts, and the weight part of the carbon-based short fiber filaments is 3.5 parts.

[0133] The preparation method of the high magnetic loss type foaming preform is only different from that of the high resistance loss type foaming preform in that: in S13, it does not contain carbon-based wave-absorbing material and carbon-based short fiber filaments, but contains 32 parts of magnetic wave-absorbing material and 11 parts of magnetic short fiber filaments.

[0134] The preparation method of the low resistance loss type three-dimensional thin-walled hollow wave-absorbing preform is as follows: Add alumina hollow spheres into the wave-absorbing slurry (the base material is carbon-based wave-absorbing material) for impregnation and mixing. The impregnation time is 1.5 min, then lift it with a wire mesh, control the liquid for 5 min, and then transfer it to a rotary screen box, rotate and dry it on the hot air surface for 10 min, and then move it into an oven for pre-curing. The pre-curing time is 1 h, and the pre-curing temperature is 150 °C. Then repeat the process of impregnation according to the above steps until the resistance value meets the requirements, but after the last impregnation and repetition process is completed, only surface drying is required without pre-curing (for the final curing adhesive between the spheres inside the honeycomb holes after surface drying). In this low resistance loss type three-dimensional thin-walled hollow wave-absorbing preform, there are 18 parts of carbon-based wave-absorbing material and 70 parts of alumina hollow sphere A.

[0135] The preparation method of the medium resistance loss type three-dimensional thin-walled hollow wave-absorbing preform is only different from that of the low resistance loss type three-dimensional thin-walled hollow wave-absorbing preform in that: according to the above steps of impregnation, 12 parts of carbon-based wave-absorbing material, 40 parts of alumina hollow spheres A, and 40 parts of alumina hollow spheres B are used, and the alumina hollow spheres A and the alumina hollow spheres B are used in a graded mixture.

[0136] The preparation method of the high resistance loss type three-dimensional thin-walled hollow wave-absorbing preform is only different from that of the low resistance loss type three-dimensional thin-walled hollow wave-absorbing preform in that: according to the above steps of impregnation, 6 parts of carbon-based wave-absorbing material and 70 parts of alumina hollow spheres B are used.

[0137] Example 1

[0138] An embodiment of the modular filling combined honeycomb of the present application. The structural schematic diagram of the modular filling combined honeycomb in this embodiment is as shown in Figure 1 Structure A in, and the preparation method is as follows:

[0139] S1. Using a cylindrical bar splitting die, hot press a high resistance loss type foamed preform, a medium resistance loss type foamed preform, and a low resistance loss type foamed preform with a size of 400mm * 400mm at 150 °C and 0.5 MPa for 3 s to obtain a cylindrical bar with a length of 400mm and a diameter of 2.1mm;

[0140] S2. Cut the cylindrical bar into high resistance loss type foamed preform blocks, medium resistance loss type foamed preform blocks, and low resistance loss type foamed preform blocks with thicknesses of 0.1 times, 0.2 times, and 0.25 times the honeycomb hole height respectively;

[0141] S3. According to the design, along a direction perpendicular to the T direction of the modular filling combined honeycomb, stack the following foamed preform blocks in sequence from bottom to top in each honeycomb hole of the honeycomb matrix:

[0142] The first honeycomb hole: a high resistance loss type foamed preform block (which is used as the first functional layer after curing, and its surface resistance is 80 - 95 kΩ / □);

[0143] The second honeycomb hole: a medium resistance loss type foamed preform block (which is used as the second functional layer after curing, and its surface resistance is 30 - 45 kΩ / □), a high resistance loss type foamed preform block;

[0144] The third honeycomb hole: a low resistance loss type foamed preform block (which is used as the third functional layer after curing, and its surface resistance is 7 - 9.5 kΩ / □), a medium resistance loss type foamed preform block, a high resistance loss type foamed preform block;

[0145] The fourth honeycomb hole: a low resistance loss type foamed preform block, a low resistance loss type foamed preform block, a medium resistance loss type foamed preform block, a high resistance loss type foamed preform block;

[0146] The fifth honeycomb hole: low-resistance-loss foam preform block, medium-resistance-loss foam preform block, high-resistance-loss foam preform block;

[0147] The sixth honeycomb hole: medium-resistance-loss foam preform block, high-resistance-loss foam preform block;

[0148] Taking the first honeycomb hole to the sixth honeycomb hole as a cycle, cycling along the direction perpendicular to the T direction of the modular filling combined honeycomb, a honeycomb semi-finished product is obtained;

[0149] S4, curing the honeycomb semi-finished product at 200 °C, and heating air is transmitted along the T direction of the honeycomb hole to obtain the modular filling combined honeycomb.

[0150] Example 2

[0151] An embodiment of the modular filling combined honeycomb of the present application. The structural schematic diagram of the modular filling combined honeycomb in this embodiment is as shown in Figure 1 the B structure in, and the preparation method is as follows:

[0152] S1, using a cylindrical bar cutting die, hot-pressing a high magnetic loss foam preform, an extremely low resistance loss foam preform, a low resistance loss foam preform, a medium resistance loss foam preform, and a high resistance loss foam preform with a size of 400 mm * 400 mm at 150 °C and 0.5 MPa for 3 s to obtain a cylindrical bar with a length of 400 mm and a diameter of 2.1 mm;

[0153] S2, cutting the high magnetic loss foam preform cylindrical bar into high magnetic loss foam preform blocks with a thickness of 0.08 times the height of the honeycomb hole, cutting the extremely low resistance loss foam preform cylindrical bar into extremely low resistance loss foam preform blocks with a thickness of 0.8 times the height of the honeycomb hole, cutting the low resistance loss foam preform cylindrical bar into low resistance loss foam preform blocks with a thickness of 0.8 times the height of the honeycomb hole, cutting the medium resistance loss foam preform cylindrical bar into medium resistance loss foam preform blocks with a thickness of 0.8 times the height of the honeycomb hole, and cutting the high resistance loss foam preform cylindrical bar into high resistance loss foam preform blocks with a thickness of 0.8 times the height of the honeycomb hole;

[0154] S3, according to the design, along a direction perpendicular to the T direction of the modular filling combined honeycomb, stack the following foam preform blocks in sequence from bottom to top in each honeycomb hole of the honeycomb matrix:

[0155] The first honeycomb hole: a high magnetic loss type foamed preform block (which becomes the fifth functional layer after curing, with an absorption band of L - S band, a magnetic permeability of 3 - 5 H / m), an extremely low resistance loss type foamed preform block (which becomes the fourth functional layer after curing, with a sheet resistance of 2.5 - 4.5 kΩ / □), a high magnetic loss type foamed preform block;

[0156] The second honeycomb hole: a high magnetic loss type foamed preform block, an extremely low resistance loss type foamed preform block, a high magnetic loss type foamed preform block;

[0157] The third honeycomb hole: a high magnetic loss type foamed preform block, a low resistance loss type foamed preform block, a high magnetic loss type foamed preform block;

[0158] The fourth honeycomb hole: a high magnetic loss type foamed preform block, a medium resistance loss type foamed preform block, a high magnetic loss type foamed preform block;

[0159] The fifth honeycomb hole: a high magnetic loss type foamed preform block, a high resistance loss type foamed preform block, a high magnetic loss type foamed preform block;

[0160] S4. Curing the honeycomb semi - finished product at 200 °C, with the hot air transmitted along the T - direction of the honeycomb hole, to obtain a modular filled combined honeycomb.

[0161] Example 3

[0162] An embodiment of the modular filled combined honeycomb of the present application. The structural schematic diagram of the modular filled combined honeycomb in this embodiment is as shown in Figure 2 the C structure in, and the preparation method is as follows:

[0163] S1. Using a cylindrical bar cutting die, hot - pressing a 400 mm * 400 mm extremely low resistance loss type foamed preform, a low resistance loss type foamed preform, a medium resistance loss type foamed preform, and a high resistance loss type foamed preform at 150 °C and 0.5 MPa for 3 s to obtain a cylindrical bar with a length of 400 mm and a diameter of 2.1 mm;

[0164] S2. Cutting the extremely low resistance loss type foamed preform cylindrical bar into extremely low resistance loss type foamed preform blocks with a thickness of 0.4 times the height of the honeycomb hole, cutting the low resistance loss type foamed preform cylindrical bar into low resistance loss type foamed preform blocks with a thickness of 0.25 times the height of the honeycomb hole, cutting the medium resistance loss type foamed preform cylindrical bar into medium resistance loss type foamed preform blocks with a thickness of 0.15 times the height of the honeycomb hole, and cutting the high resistance loss type foamed preform cylindrical bar into high resistance loss type foamed preform blocks with a thickness of 0.1 times the height of the honeycomb hole;

[0165] S3. According to the design, along a direction perpendicular to the T direction of the modular filled combined honeycomb, the following foamed prefabricated blocks are stacked in sequence from bottom to top in each honeycomb hole of the honeycomb matrix:

[0166] Honeycomb hole: extremely low resistance loss type foamed prefabricated block, low resistance loss type foamed prefabricated block, medium resistance loss type foamed prefabricated block, high resistance loss type foamed prefabricated block;

[0167] S4. The honeycomb semi-finished product is cured at 200 °C, and the heating air is transmitted along the T direction of the honeycomb hole to obtain the modular filled combined honeycomb.

[0168] Example 4

[0169] An embodiment of the modular filled combined honeycomb of the present application. The structural schematic diagram of the modular filled combined honeycomb in this embodiment is as shown in Figure 2 the D structure in, and the preparation method is as follows:

[0170] S1. Using a cylindrical bar cutting die, a 400 mm × 400 mm extremely low resistance loss type foamed prefabricated body is hot-pressed at 150 °C and 0.5 MPa for 3 s to obtain a cylindrical bar with a length of 400 mm and a diameter of 2.1 mm;

[0171] S2. The extremely low resistance loss type foamed prefabricated body cylindrical bar is cut into extremely low resistance loss type foamed prefabricated blocks with a thickness of 0.2 times the height of the honeycomb hole;

[0172] S3. According to the design, along a direction perpendicular to the T direction of the modular filled combined honeycomb, the following prefabricated blocks are stacked in sequence from bottom to top in each honeycomb hole of the honeycomb matrix:

[0173] Honeycomb hole: extremely low resistance loss type foamed prefabricated block, a low resistance loss type three-dimensional thin-walled hollow absorbing prefabricated body layer with a thickness of 0.3 times the height of the honeycomb hole formed by stacking low resistance loss type three-dimensional thin-walled hollow absorbing prefabricated bodies (after curing, it serves as the sixth functional layer, and its sheet resistance is 5 - 7 kΩ / sq), a medium resistance loss type three-dimensional thin-walled hollow absorbing prefabricated body layer with a thickness of 0.3 times the height of the honeycomb hole formed by stacking medium resistance loss type three-dimensional thin-walled hollow absorbing prefabricated bodies (after curing, it serves as the seventh functional layer, and its sheet resistance is 10 - 25 kΩ / sq), a high resistance loss type three-dimensional thin-walled hollow absorbing prefabricated body layer with a thickness of 0.2 times the height of the honeycomb hole formed by stacking high resistance loss type three-dimensional thin-walled hollow absorbing prefabricated bodies (after curing, it serves as the eighth functional layer, and its sheet resistance is 50 - 73 kΩ / sq);

[0174] S4. The honeycomb semi-finished product is cured at 200 °C, and the heating air is transmitted along the T direction of the honeycomb hole to obtain the modular filled combined honeycomb.

[0175] Example 5

[0176] An embodiment of the modular filling combined honeycomb of the present application. The structural schematic diagram of the modular filling combined honeycomb in this embodiment is as shown in Figure 2 the E structure in, and the preparation method is as follows:

[0177] S1. Using a cylindrical bar slitting die, hot press a high-resistance loss foam preform, a medium-resistance loss foam preform, a low-resistance loss foam preform, and an extremely low-resistance loss foam preform with a size of 400 mm × 400 mm at 150 °C and 0.3 MPa for 3 s to obtain cylindrical bars with a length of 400 mm and a diameter of 2.1 mm;

[0178] S2. Cut the high-resistance loss foam preform cylindrical bars into high-resistance loss foam preform blocks with a thickness of 0.1 times the honeycomb hole height, cut the medium-resistance loss foam preform cylindrical bars into medium-resistance loss foam preform blocks with a thickness of 0.1 times the honeycomb hole height, cut the low-resistance loss foam preform cylindrical bars into low-resistance loss foam preform blocks with a thickness of 0.15 times the honeycomb hole height, and cut the extremely low-resistance loss foam preform cylindrical bars into extremely low-resistance loss foam preform blocks with a thickness of 0.3 times the honeycomb hole height;

[0179] S3. According to the design, along a direction perpendicular to the T direction of the modular filling combined honeycomb, stack the following foam preform blocks in sequence from bottom to top in each honeycomb hole of the honeycomb matrix:

[0180] Honeycomb hole: high-resistance loss foam preform block, medium-resistance loss foam preform block, low-resistance loss foam preform block, extremely low-resistance loss foam preform block, low-resistance loss foam preform block, medium-resistance loss foam preform block, high-resistance loss foam preform block.

[0181] S4. Cure the honeycomb semi-finished product at 200 °C, and let the hot air transfer along the T direction of the honeycomb holes to obtain the modular filling combined honeycomb.

[0182] Example 6

[0183] An embodiment of the modular filling combined honeycomb of the present application. The structural schematic diagram of the modular filling combined honeycomb in this embodiment is as shown in Figure 3 , and its difference from Example 4 is only that the honeycomb matrix is a curved surface structure.

[0184] Performance test

[0185] Perform performance tests on Examples 1 to 5. The test method is as follows, and the test results are shown in Table 1.

[0186] 1) Absorbing wave performance:

[0187] The test method adopts the reflectivity test method of radar absorbing materials in GJB2038 to test the average value of the vertical reflectivity in the T direction of the honeycomb core material. The sample size is an absorbing honeycomb with dimensions of 300±2 mm (L) * 300±2 mm (W) * 40±1 mm (T).

[0188] Performance description: The quality of the flat panel's reflection and absorption performance cannot directly represent the quality of the stealth components of the characteristic structures of each corresponding part of the airframe. Because the flat panel reflection test is for the electromagnetic wave absorption and reflection performance in the honeycomb thickness direction, while the airframe stealth components are comprehensively evaluated based on the usage characteristics of each part (corresponding embodiments) and the RCS absorption and stealth characteristics of the main direction of the radar electromagnetic wave search on the front of the airframe. Each has its own advantages.

[0189] 2) Mechanical properties:

[0190] The test method adopts ASTM C365 / 365M to test the room temperature compressive strength and modulus of the stabilized honeycomb core material. The standard size of the specimen is 50±1.3 mm (L) * 50±1.3 mm (W) * 12.7±0.15 mm (T).

[0191] Table 1

[0192]

[0193]

[0194] It can be seen from the above test results that the modular filling combined honeycomb in the embodiments of the present application not only has good wave absorption performance, but also has excellent mechanical properties, high structural stability, and is suitable for applications in multiple fields such as aircraft, ships, and ground vehicles.

[0195] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A modular filled combined honeycomb, characterized in that, The modular filling combined honeycomb includes a plurality of honeycomb holes filled with functional materials, and the functional materials in each honeycomb hole are the same or different; each of the functional materials includes a foaming material.

2. The modular filling combined honeycomb according to claim 1, wherein Each of the functional materials independently includes at least one of a first functional layer, a second functional layer, a third functional layer, a fourth functional layer, a fifth functional layer, a sixth functional layer, a seventh functional layer, and an eighth functional layer; when the functional material includes multiple functional layers, each of the functional layers is stacked along the T direction of the modular filling combined honeycomb to form the functional material; the thickness of each of the functional layers is independently 0.05 to 1 times the height of the honeycomb hole; Preferably, the material of the first functional layer is a high-resistance loss type foaming material, its surface resistance is 50 to 100 kΩ / square, and its composition does not include hollow wave-absorbing microspheres; Preferably, the material of the second functional layer is a medium-resistance loss type foaming material, its surface resistance is 10 to 50 kΩ / square, and its composition does not include hollow wave-absorbing microspheres; Preferably, the material of the third functional layer is a low-resistance loss type foaming material, its surface resistance is 5 to 10 kΩ / square, and its composition does not include hollow wave-absorbing microspheres; Preferably, the material of the fourth functional layer is an extremely low-resistance loss type foaming material, its surface resistance is 1 to 5 kΩ / square, and its composition does not include hollow wave-absorbing microspheres; Preferably, the material of the fifth functional layer is a high-magnetic loss type foaming material, and its magnetic permeability is 3 to 5 H / m; Preferably, the material of the sixth functional layer is a low-resistance loss type three-dimensional thin-walled hollow wave-absorbing material, its surface resistance is 5 to 10 kΩ / square, and its composition includes hollow wave-absorbing microspheres; Preferably, the material of the seventh functional layer is a medium-resistance loss type three-dimensional thin-walled hollow wave-absorbing material, its surface resistance is 10 to 50 kΩ / square, and its composition includes hollow wave-absorbing microspheres; Preferably, the material of the eighth functional layer is a high-resistance loss type three-dimensional thin-walled hollow wave-absorbing material, its surface resistance is 50 to 100 kΩ / square, and its composition includes hollow wave-absorbing microspheres.

3. The modular filling combined honeycomb according to claim 2, characterized in that Along any direction perpendicular to the T direction of the modular filling combined honeycomb, the following functional materials are sequentially and cyclically filled in each honeycomb hole: a first functional material, a second functional material, a third functional material, a fourth functional material, a third functional material, and a second functional material; The first functional material is composed of a first functional layer; The second functional material: the second functional layer and the first functional layer are stacked in sequence from bottom to top; The third functional material: the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top; The fourth functional material: the third functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top; Among them, the thickness of the first functional layer is 0.05 to 0.15 times the height of the honeycomb hole, the thickness of the second functional layer is 0.15 to 0.2 times the height of the honeycomb hole, and the thickness of the third functional layer is 0.15 to 0.25 times the height of the honeycomb hole.

4. The modular filling combined honeycomb according to claim 2, wherein, Along any direction perpendicular to the T direction of the modular filling combined honeycomb, the following functional materials are filled in each honeycomb hole in sequence: The fifth functional material: The fifth functional layer, the fourth functional layer, and the fifth functional layer are stacked in sequence from bottom to top; The fifth functional material; The sixth functional material: The fifth functional layer, the third functional layer, and the fifth functional layer are stacked in sequence from bottom to top; The seventh functional material: The fifth functional layer, the second functional layer, and the fifth functional layer are stacked in sequence from bottom to top; The eighth functional material: The fifth functional layer, the first functional layer, and the fifth functional layer are stacked in sequence from bottom to top; Wherein, the thickness of the first functional layer is 0.7 - 0.9 times the height of the honeycomb holes, the thickness of the second functional layer is 0.7 - 0.9 times the height of the honeycomb holes, the thickness of the third functional layer is 0.7 - 0.9 times the height of the honeycomb holes, the thickness of the fourth functional layer is 0.7 - 0.9 times the height of the honeycomb holes, and the thickness of the fifth functional layer is 0.05 - 0.15 times the height of the honeycomb holes.

5. The modular filling combined honeycomb according to claim 2, characterized in that Along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are filled in each of the honeycomb holes: The ninth functional material: The fourth functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top; Wherein, the thickness of the first functional layer is 0.05 - 0.15 times the height of the honeycomb holes, the thickness of the second functional layer is 0.1 - 0.2 times the height of the honeycomb holes, the thickness of the third functional layer is 0.2 - 0.3 times the height of the honeycomb holes, and the thickness of the fourth functional layer is 0.3 - 0.5 times the height of the honeycomb holes.

6. The modular filling combined honeycomb according to claim 2, characterized in that, Along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are filled in each of the honeycomb holes: The tenth functional material: The fourth functional layer, the sixth functional layer, the seventh functional layer, and the eighth functional layer are stacked in sequence from bottom to top; Wherein, the thickness of the fourth functional layer is 0.2 - 0.3 times the height of the honeycomb holes, the thickness of the sixth functional layer is 0.2 - 0.4 times the height of the honeycomb holes, the thickness of the seventh functional layer is 0.2 - 0.3 times the height of the honeycomb holes, and the thickness of the eighth functional layer is 0.1 - 0.2 times the height of the honeycomb holes.

7. The modular filling combined honeycomb according to claim 6, characterized in that, The sixth functional layer, the seventh functional layer, and the eighth functional layer each independently include at least one of graded A balls with a diameter of 1 - 1.5 mm and graded B balls with a diameter of 2.2 - 3 mm.

8. The modular filling combined honeycomb according to claim 2, wherein, Along any direction perpendicular to the modular filling combined honeycomb T direction, the following functional materials are filled in each of the honeycomb holes: The eleventh functional material: The first functional layer, the second functional layer, the third functional layer, the fourth functional layer, the third functional layer, the second functional layer, and the first functional layer are stacked in sequence from bottom to top; Wherein, the thickness of the first functional layer is 0.05 - 0.1 times the height of the honeycomb holes, the thickness of the second foam layer is 0.1 - 0.15 times the height of the honeycomb holes, the thickness of the third foam layer is 0.1 - 0.15 times the height of the honeycomb holes, and the thickness of the fourth foam layer is 0.2 - 0.4 times the height of the honeycomb holes.

9. A preparation method of the modular filling combined honeycomb according to any one of claims 1 to 8, characterized in that, Including the following steps: S1. Prepare different types of foamed preforms and thin-walled hollow wave-absorbing preforms to obtain high-resistance-loss foamed preforms, medium-resistance-loss foamed preforms, low-resistance-loss foamed preforms, extremely low-resistance-loss foamed preforms, high-magnetic-loss foamed preforms, low-resistance-loss three-dimensional thin-walled hollow wave-absorbing preforms, medium-resistance-loss three-dimensional thin-walled hollow wave-absorbing preforms, and high-resistance-loss three-dimensional thin-walled hollow wave-absorbing preforms; S2. Cut the different types of foamed preforms respectively to obtain different cylindrical bars; S3. Cut the different cylindrical bars according to the required thickness to obtain the same or different foamed preform blocks; S4. Stack the foamed preform blocks, or the foamed preform blocks and the thin-walled hollow wave-absorbing preforms, from bottom to top in different honeycomb holes of the modular filling combined honeycomb according to the design to obtain a honeycomb semi-finished product; S4. Cure the honeycomb semi-finished product to obtain the modular filling combined honeycomb; Preferably, the diameter of the cylindrical bar is 50% - 80% of the diameter of the honeycomb hole.

10. Application of a modular filled combined honeycomb in a stealth device, characterized in that, The modular filling combined honeycomb is the modular filling combined honeycomb described in any one of claims 1 to 8 or the modular filling combined honeycomb obtained by the preparation method described in claim 9.

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