A small-aperture honeycomb wave-absorbing plate for a shelter and a preparation method thereof

Abstract

The present invention provides a small-aperture honeycomb absorbing panel for a shelter cabin. The panel comprises an upper skin, a surface absorbing honeycomb core, an intermediate absorbing honeycomb core, a bottom absorbing honeycomb core, and a lower skin, stacked in order from top to bottom. The surface and bottom absorbing honeycomb cores are made of a small-aperture aramid honeycomb core, each coated with an absorbing coating. The upper and lower skins are formed by hot-pressing glass fiber epoxy resin prepreg. The shelter cabin of the present invention utilizes a multi-layer honeycomb absorbing structure, which improves absorption strength and broadens the absorption frequency band. Furthermore, the small-aperture aramid honeycomb core material employed in the present invention increases the bonding area between the honeycomb core and the skin, reduces the risk of debonding, enhances the skin surface appearance, and improves the reliability of the cabin panel, resulting in high commercial value.

Description

Technical Field

[0001] The present invention relates to the technical field of square cabins, and in particular to a small-aperture honeycomb wave-absorbing plate for a square cabin body and a preparation method thereof. Background Art

[0002] Existing shelters are primarily categorized into skeleton-type and large-panel splicing-type shelters, depending on their structure and function. The wall panels are primarily made of fiberglass or carbon fiber skins, with internal sandwich structures made of polyurethane foam and honeycomb cores. The honeycomb absorbing panels of the shelter body are constructed using a regular hexagonal aramid paper honeycomb core as the base material. A specially formulated absorbing coating with varying concentrations is applied to the honeycomb walls, and then the upper and lower surfaces of the honeycomb core are covered with skins.

[0003] At present, the absorbing coating is applied to the honeycomb wall of the aramid paper honeycomb core by the dipping process. When dipping the honeycomb core with a thickness of 5mm or more, the pore blocking phenomenon is easy to occur. In order to avoid the serious pore blocking phenomenon, the honeycomb core with a cell side length of 3.67mm or more is usually used. However, it has the following shortcomings: (1) Debonding between the skin and the honeycomb, which reduces the reliability of the application. The honeycomb core with a cell side length of 3.67mm or more currently used has a large pore size, and the bonding surface between the honeycomb and the skin is small. After the environmental adaptability test, the air volume changes in the honeycomb core due to temperature changes. There are local debonding and weak bonding between the skin and the absorbing honeycomb core, which leads to bulging, reducing the reliability of the cabin application. (2) The skin surface is uneven and unsightly. The change in the air volume in the honeycomb pore size in the cabin body exerts a force on the skin. Therefore, under the environment of temperature shock, humidity and heat, the skin in each cell unit has different degrees of honeycomb pore-like depressions or protrusions, affecting the overall flatness of the cabin outer surface.

[0004] Chinese patent document CN112646353A provides an impact-resistant absorbing panel, comprising: an impact-resistant skin, a radar absorbing layer, and a reflective layer. The radar absorbing layer comprises one of aramid honeycomb, polyurethane foam, and PMI foam. While ensuring high-performance radar absorbing performance, the impact resistance of the skin is achieved, thereby significantly improving the surface strength of the absorbing panel and greatly improving the adaptability of combat equipment to field environments. However, the above-mentioned honeycomb structure absorbing panel also has the characteristic of a narrow absorbing frequency band, which cannot meet the requirements of broadband and strong absorption of the cabin body. In addition, according to the impedance matching principle, the cabin panel usually adopts a multi-layer structure design with a total thickness of more than 24 mm.

[0005] Therefore, there is an urgent need to provide a honeycomb absorbing panel that has strong broadband absorption, strong bonding, and can achieve beautiful cabin appearance. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the main purpose of the present invention is to provide a small-aperture honeycomb absorbing plate for a cabin body, which can combine the aramid honeycomb structure and the small-aperture honeycomb structure with each other, while achieving broadband strong absorption to meet the use of the cabin, enhancing the firmness of the bonding between the cabin body and the honeycomb structure, and ensuring the beauty of the cabin body.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A small-aperture honeycomb absorbing panel for a cabin body comprises an upper skin, a surface absorbing honeycomb core, an intermediate absorbing honeycomb core, a bottom absorbing honeycomb core, and a lower skin stacked in sequence from top to bottom. The surface absorbing honeycomb core and the bottom absorbing honeycomb core are made of a small-aperture aramid honeycomb core, and the absorbing honeycomb cores are coated with an absorbing coating. The upper and lower skins are made of glass fiber epoxy resin prepreg by hot pressing.

[0009] Furthermore, there are adhesive film layers between the upper skin and the surface absorbing honeycomb core, and between the lower skin and the bottom absorbing honeycomb core.

[0010] Furthermore, the small-aperture aramid honeycomb core has a regular hexagonal shape with a side length of 1.83-2.75 mm and a thickness of 2-4 mm.

[0011] Furthermore, the small-aperture aramid honeycomb core has a side length of 1.83 mm and a thickness of 2 to 4 mm.

[0012] Furthermore, the material used for the intermediate layer of the wave-absorbing honeycomb core is an aramid honeycomb core, which has a regular hexagonal shape, a side length of 3.67-5.5 mm, and a thickness of 5-12 mm.

[0013] Furthermore, the absorbing coating comprises, by weight, 150-200 parts of absorbent, 750-850 parts of base resin, 80-100 parts of wetting agent, 3500-3700 parts of water, 3-6 parts of leveling agent and 0.1-0.5 parts of anti-settling agent.

[0014] Furthermore, the absorbing coating comprises, by weight, 180 parts of absorbent, 800 parts of base resin, 90 parts of wetting agent, 3600 parts of water, 5 parts of leveling agent and 0.2 parts of anti-settling agent.

[0015] Furthermore, the absorbent is one of carbon black, carbon fiber or graphene; the matrix resin is one of polyurethane modified silicone resin, epoxy modified silicone resin or acrylic modified silicone resin; the wetting agent is polyoxyethylene alkyl aryl ether; the leveling agent is one of polyester modified polydimethylsiloxane or acrylic copolymer; the anti-settling agent is one of organic bentonite, modified polyurea compound or fumed silica.

[0016] Furthermore, the absorbent is carbon black; the base resin is polyurethane; the wetting agent is polyoxyethylene alkyl aryl ether; the leveling agent is polyester-modified polydimethylsiloxane; and the anti-settling agent is organic bentonite.

[0017] Another object of the present invention is to provide a method for preparing a small-aperture honeycomb absorbing plate for a shelter, comprising the following steps:

[0018] S1. Preparing a radar absorbing coating: Weighing the raw materials according to the weight ratio, mixing and stirring uniformly to obtain the radar absorbing coating;

[0019] S2, dipping the small-pore aramid honeycomb core into the microwave-absorbing coating, weighing it after surface drying, repeating the dipping until the designed weight is reached, and then drying and curing it to obtain the surface-layer microwave-absorbing honeycomb core and the bottom-layer microwave-absorbing honeycomb core;

[0020] S3, dipping the aramid honeycomb core into the microwave-absorbing coating, weighing it after surface drying, repeating the dipping until the designed weight is reached, and then drying and curing it to obtain the intermediate layer microwave-absorbing honeycomb core;

[0021] S4. Lay the upper skin, film layer, surface absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, bottom absorbing honeycomb core, film layer and lower skin in this order, then place them on a flat hot press and heat-press and cure them to obtain the cabin deck absorbing panel.

[0022] Furthermore, in step S2, the coating amount of the surface absorbing honeycomb core is 50-100 g / m 2 The coating amount of the bottom absorbing honeycomb core is 800-1000g / m 2 .

[0023] Furthermore, the amount of the absorbing coating on the surface absorbing honeycomb core is 60 g / m 2 The amount of the absorbing coating on the bottom absorbing honeycomb core is 800g / m 2 .

[0024] Furthermore, in step S3, the coating amount of the intermediate layer absorbing honeycomb core is 100-200 g / m 2 , 300-400g / m 2 and 500-600g / m 2 .

[0025] Furthermore, the coating amount of the intermediate absorbing honeycomb core is 150g / m 2 , 320g / m 2 and 580g / m2 .

[0026] Furthermore, in step S4, the glass fiber cloth weight of the prepreg is 210g, and the resin content is 50%.

[0027] Furthermore, in step S2, the curing temperature is 80°C and the curing time is 15-30 minutes. Under such conditions, the surface layer absorbing honeycomb core and the bottom layer absorbing honeycomb core of the designed weight can be obtained by impregnation and curing.

[0028] Furthermore, in step S3, the curing temperature is 80° C. and the curing time is 20-30 min. Under these conditions, the impregnation and curing can obtain an intermediate layer absorbing honeycomb core of designed weight.

[0029] The shelter panel wave-absorbing plate obtained by the above-mentioned preparation method has good mechanical properties and environmental resistance, and can be widely used in various types of military shelters.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The cabin absorbing plate of the present invention adopts a multi-layer honeycomb absorbing structure, and the absorbing honeycomb core is impregnated with an absorbing coating. By performing impedance matching design on the upper skin, the surface absorbing honeycomb core, the middle absorbing honeycomb core, and the bottom absorbing honeycomb core, the absorbing strength is further improved and the absorbing frequency band is broadened while meeting the environmental use conditions.

[0032] 2. The surface layer of the cabin body absorbing plate and the bottom absorbing honeycomb core of the present invention adopt small-aperture aramid honeycomb core material, which increases the bonding area between the honeycomb core and the skin, reduces the risk of debonding, makes the skin surface more beautiful, improves the reliability of the cabin plate application, and has high commercial value.

[0033] 3. The cabin absorbing plate of the present invention not only meets the requirements of high absorption over a wide frequency band, but also adopts a small-aperture aramid honeycomb core material to reduce the risk of debonding, making the skin surface more beautiful, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 Schematic diagram of the structure of the small-aperture honeycomb absorbing plate of the present invention;

[0036] In the figure: 1. Upper skin, 2. Surface absorbing honeycomb core, 3. Middle absorbing honeycomb core, 4. Prepreg, 5. Bottom absorbing honeycomb core, 6. Adhesive film, 7. Lower skin.

[0037] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are described clearly and completely below. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0039] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0040] like Figure 1 As shown in FIG, the present invention provides a small-aperture honeycomb wave-absorbing plate for a cabin body, comprising:

[0041] Upper skin 1;

[0042] The surface absorbing honeycomb core 2 is bonded to the upper skin 1 through a film;

[0043] Intermediate layer of wave-absorbing honeycomb core 3;

[0044] Prepreg 4;

[0045] The bottom absorbing honeycomb core 5 and the lower skin 7 are bonded to each other through a film;

[0046] Lower skin 7;

[0047] It should be noted that the material used for the surface absorbing honeycomb core 2 and the bottom absorbing honeycomb core 5 is a regular hexagonal small-aperture aramid honeycomb core, that is, the side length of the small-aperture aramid honeycomb core is 1.83-2.75 mm, and the thickness is 2-4 mm. Preferably, the side length of the small-aperture aramid honeycomb core is 1.83 mm and the thickness is 4 mm; the material used for the middle layer absorbing honeycomb core 3 is a regular hexagonal aramid honeycomb core, that is, the side length of the aramid honeycomb core is 3.67-5.5 mm, and the thickness is 5-12 mm. Preferably, the side length is 3.67 mm and the thickness is 5 mm; the upper skin and the lower skin are made of glass fiber epoxy resin prepreg by hot pressing.

[0048] The following further describes the method for preparing the small-aperture honeycomb wave-absorbing plate for the cabin body with specific examples.

[0049] Example 1

[0050] S1, 180g of carbon black, 800g of polyurethane, 90g of polyoxyethylene alkyl aryl ether, 3600g of water, 5g of polyester-modified polydimethylsiloxane and 0.2g of organic bentonite were mixed and stirred to obtain the radar absorbing coating;

[0051] S2. Two regular hexagonal small-aperture aramid honeycomb cores with a cell side length of 1.83 mm and a thickness of 4 mm were subjected to multiple dipping in a microwave-absorbing coating method and dried at 80° C. for 30 min to obtain a surface-layer microwave-absorbing honeycomb core and a bottom-layer microwave-absorbing honeycomb core;

[0052] Among them, the surface absorbing honeycomb core has an absorbing coating coating amount of 60g / m 2 The amount of absorbing coating on the bottom absorbing honeycomb core is 800g / m 2 ;

[0053] S3. Three regular hexagonal aramid honeycomb cores with a cell side length of 3.67 mm and a thickness of 5 mm were repeatedly dipped in a microwave-absorbing coating and dried and cured at 80° C. for 30 min to obtain an intermediate-layer microwave-absorbing honeycomb core.

[0054] Among them, the coating amount of the absorbing coating of the middle layer absorbing honeycomb core is 150g / m 2 , 320g / m 2 and 580g / m 2 ;

[0055] S4. Lay the layers in the order of upper skin, adhesive film, surface absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, bottom absorbing honeycomb core, adhesive film, and lower skin, and then place the layers on a flat hot press for hot pressing and curing to obtain the shelter absorbing cabin panel.

[0056] The glass fiber prepreg used in step S4 has a weight of 210 g and a resin content of 50%.

[0057] Example 2

[0058] The same method as in Example 1 was used to prepare the cabin panel absorbing plate. The only difference from Example 1 was that in step S2, the absorbing coating of the surface absorbing honeycomb core was increased in weight by 80 g / m 2 The amount of absorbing coating on the bottom absorbing honeycomb core is 1000g / m 2 In step S3, the coating amount of the intermediate layer of the absorbing honeycomb core is 180g / m 2 , 380g / m 2 and 600g / m 2 .

[0059] Example 3

[0060] The cabin cabin panel absorbing plate was prepared in the same manner as in Example 1, except that in step S1, the formula of the absorbing coating was 200 g of graphene, 850 g of polyurethane, 100 g of polyoxyethylene alkyl aryl ether, 3700 g of water, 6 g of polyester-modified polydimethylsiloxane, and 0.5 g of organic bentonite.

[0061] Comparative Example 1

[0062] The cabin deck absorbing plate was prepared in the same manner as in Example 1, with the only difference from Example 1 being that in step S2, both the surface absorbing honeycomb core and the bottom absorbing honeycomb core were regular hexagonal aramid honeycomb cores with a cell side length of 3.67 mm and a thickness of 5 mm.

[0063] The honeycomb absorbing panels obtained in Examples 1-3 and Comparative Example 1 were subjected to tensile strength, shear strength, peel strength, temperature shock, and humidity tests, respectively, to evaluate the comprehensive performance of the materials through mechanical properties and environmental resistance. The test table is shown in Table 1:

[0064] Table 1 Honeycomb absorbing panel performance test results

[0065]

[0066] Note: a: Temperature shock conditions are 69℃±2℃ / -41℃±2℃, 1h respectively, cycle time 1min, and 5 cycles;

[0067] b: The hot and humid conditions are high temperature and high humidity stage: temperature 60℃, relative humidity 95%; low temperature and high humidity stage: temperature 30℃, relative humidity 95%; detection time: each cycle 24h, 10 cycles.

[0068] The test results in Table 1 show that the embodiments of the present invention have significant advantages over the comparative examples in terms of mechanical properties and environmental resistance. In particular, Example 1 has the most significant advantages in terms of mechanical properties and environmental resistance, and there is no bulging or depression on the surface of the absorbing plate. The absorbing plate designed by this method can ensure strong broadband absorption while reducing the risk of skin debonding and bulging, thereby beautifying the appearance and enhancing reliability, and can be applied to various types of military shelters.

[0069] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A small-aperture honeycomb wave-absorbing plate for a shelter, characterized by: The invention comprises an upper skin, a film layer, a surface absorbing honeycomb core, a prepreg, an intermediate absorbing honeycomb core, a prepreg, an intermediate absorbing honeycomb core, a prepreg, an intermediate absorbing honeycomb core, a prepreg, a bottom absorbing honeycomb core, a film layer and a lower skin, which are stacked in sequence from top to bottom. The surface absorbing honeycomb core and the bottom absorbing honeycomb core are made of small-aperture aramid honeycomb cores, each of which is coated with an absorbing coating. The upper skin and the lower skin are made by hot-pressing glass fiber epoxy resin prepreg. The small-aperture aramid honeycomb core is in the shape of a regular hexagon with a side length of 1.83-2.75 mm and a thickness of 2-4 mm. The intermediate absorbing honeycomb core is made of an aramid honeycomb core in the shape of a regular hexagon with a side length of 3.67-5.5 mm and a thickness of 5-12 mm.

2. The small-aperture honeycomb wave-absorbing plate for a shelter according to claim 1, characterized in that: The wave-absorbing coating comprises, by weight, 150-200 parts of absorbent, 750-850 parts of base resin, 80-100 parts of wetting agent, 3500-3700 parts of water, 3-6 parts of leveling agent, and 0.1-0.5 parts of anti-settling agent.

3. The small-aperture honeycomb wave-absorbing plate for a shelter according to claim 2, characterized in that: The absorbent is one of carbon black, carbon fiber or graphene; The matrix resin is one of polyurethane-modified silicone resin, epoxy-modified silicone resin or acrylic-modified silicone resin; The wetting agent is polyoxyethylene alkyl aryl ether; The leveling agent is one of polyester-modified polydimethylsiloxane or acrylic copolymer; The anti-settling agent is one of organic bentonite, modified polyurea compound or fumed silica.

4. The method for preparing a small-aperture honeycomb wave-absorbing plate for a shelter according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Preparing a radar absorbing coating: Weighing various raw materials, mixing and stirring them uniformly to obtain the radar absorbing coating; S2. Dipping a small-pore aramid honeycomb core into the microwave-absorbing coating, weighing it after surface drying, repeating the dipping process until the designed weight is reached, and then drying and curing it to obtain the surface-layer microwave-absorbing honeycomb core and the bottom-layer microwave-absorbing honeycomb core; S3, dipping the aramid honeycomb core into the microwave-absorbing coating, weighing it after surface drying, repeating the dipping until the designed weight is reached, and then drying and curing it to obtain the intermediate layer microwave-absorbing honeycomb core; S4. Lay the upper skin, film layer, surface absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, middle absorbing honeycomb core, prepreg, bottom absorbing honeycomb core, film layer and lower skin in this order, then place them on a flat hot press and heat-press and cure them to obtain the small-aperture honeycomb absorbing panel for the cabin body.

5. The method for preparing a small-aperture honeycomb wave-absorbing plate for a shelter according to claim 4, characterized in that: In step S2, the amount of the absorbing coating on the surface absorbing honeycomb core is 50-100 g / m 2 The coating amount of the bottom absorbing honeycomb core is 800-1000g / m 2 .

6. The method for preparing a small-aperture honeycomb wave-absorbing plate for a shelter according to claim 4, characterized in that: In step S3, the coating amount of the intermediate absorbing honeycomb core is 100-200 g / m 2 , 300-400g / m 2 and 500-600g / m 2 .

7. The method for preparing a small-aperture honeycomb wave-absorbing plate for a shelter according to claim 4, characterized in that: In step S2, the curing temperature is 80° C. and the curing time is 15-30 minutes.

8. The method for preparing a small-aperture honeycomb wave-absorbing plate for a shelter according to claim 4, characterized in that: In step S3, the curing temperature is 80° C. and the curing time is 20-30 minutes.

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