CN105563964B - Composite material for airborne radome and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of airborne radome composite and preparation method thereof, wherein airborne radome includes face coat, exterior skin layer, laminboard layer and Inner Mongol cortex with composite, laminboard layer is located between exterior skin layer and Inner Mongol cortex, and face coat is coated on exterior skin layer surface；The thickness of exterior skin layer is 0.2~1mm；Laminboard layer is made of polymethacrylimide foam, structure in a rectangular trapezoid, and its short side thickness is 4~30mm, and long side thickness is 4.5mm~34mm；The thickness of Inner Mongol cortex is 0.2~1mm.Its preparation method includes：Hand paste dipping prepare Inner Mongol cortex prepreg, be coated with sandwich layer material, solidification, hand paste dipping prepare exterior skin layer prepreg, solidification, sprayed surface coating, solidification.The airborne radome composite of the present invention has that environmental resistance is excellent, integrated carrying ability is good, the advantages such as high wave transmission rate can be kept in two waveband.

Description

Composite material for airborne radome and preparation method thereof

technical field

The invention relates to the technical field of aerospace materials, in particular to a resin-based composite material for an airborne radome and a preparation method thereof.

Background technique

The airborne radome is an important part of the aircraft. Its function is to protect the internal antenna from the harsh environment during the working process, and at the same time ensure the normal operation of the antenna, that is, it has a high transmittance within the operating frequency range of the antenna.

The performance of the radome is closely related to the performance of the selected material, and the radome material should have the following characteristics:

1. The structure has good load-bearing performance and meets the strength and stiffness requirements under service load conditions;

2. The dielectric constant and dielectric loss are small, and the low dielectric constant will reduce the reflection, so that the influence of reflection on the radiation mode and insertion loss is minimized;

3. Light weight, reducing the overall weight of the radome, thereby increasing the payload ratio of the equipment;

4. Excellent environmental resistance, can effectively resist high and low temperature, low air pressure, rain, solar radiation, damp heat, mold, salt spray, sand and dust and other harsh environmental loads under service conditions;

5. Good manufacturability, realizing low-cost preparation.

Radome materials mainly include organic materials and inorganic non-metallic materials. Among them, inorganic materials such as ceramics, glass-ceramics, and ceramic-based composite materials are developed to meet the radome of aircraft with a higher Mach number. Such materials must withstand higher operating temperatures and harsher environments.

Organic materials refer to resin-based composite materials. Resin-based composite materials are the earliest materials used in radome applications and are currently the most widely used radome materials in the aerospace field. They are mainly suitable for aircraft with a small flying Mach number. The upgrading and performance of weapons and equipment have been greatly improved, and higher and higher requirements are placed on the performance of resin-based composite radomes. For some antennas, in order to improve work efficiency, the antenna is required to work in two bands, which means that the matching radome should also maintain high transmittance in the two bands. Although the existing resin-based composite materials can achieve broadband and high wave transmittance in one wave band, there is no radome material that can maintain high wave transmittance in two wave bands.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, and provide a composite material for an airborne radome with good structural load-bearing performance, excellent environmental resistance, low density and high wave transmittance in dual bands, The preparation method of the composite material for the airborne radome is also provided.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

A composite material for an airborne radome, comprising a surface coating, an outer skin layer, a sandwich layer and an inner skin layer, the sandwich layer being sandwiched between the outer skin layer and the inner skin layer, the surface coating layer on the surface of the outer skin layer; the thickness of the outer skin layer is 0.2-1mm; the sandwich layer is made of polymethacrylimide foam, which is a right-angled trapezoidal structure, and the thickness of its short side is 4-30mm , the thickness of the long side is 4.5mm-34mm; the thickness of the inner skin layer is 0.2-1mm.

For the above-mentioned composite material for airborne radome, preferably, the sandwich core layer is a right-angled trapezoid made of polymethacrylimide foam, the outer skin layer is arranged on the hypotenuse of the sandwich layer, and the inner skin layer is arranged On the right-angled side opposite to the hypotenuse of the sandwich layer; the thickness of the short side of the sandwich layer is 4-30 mm, and the thickness of the long side of the sandwich layer is 0.5-4 mm thicker than the short side; The outer skin layer and the inner skin layer are uniform and equal-thick rectangles.

The composite material for the above-mentioned airborne radome, preferably, the surface coating includes a primer layer, a rain erosion-resistant paint layer and an antistatic paint layer, and the rain-resistant paint layer is arranged on the primer layer and the In the middle of the antistatic paint layer, the primer layer is coated on the surface of the outer skin layer.

The above-mentioned composite material for airborne radome, preferably, the material of the primer layer is H01-89, and the thickness is 0.03±0.01mm; the material of the rain-resistant paint layer is SF55-49, and the thickness is 0.15± 0.02mm; the material of the antistatic paint layer is SDT99-49, and the thickness is 0.03-0.05mm.

For the above-mentioned composite material for airborne radome, preferably, the outer skin layer adopts a fiber cloth reinforced epoxy resin system composite material; the fiber cloth reinforced epoxy resin system composite material is composed of multiple layers of fiber cloth through the It is pasted together; the fiber cloth is one of quartz fiber plain weave, quartz fiber twill and quartz fiber satin weave; the epoxy resin system includes epoxy resin and a curing agent. Further preferably, the epoxy resin is LT5089A, and the curing agent is LT5089B.

For the above-mentioned composite material for an airborne radome, preferably, in the outer skin layer, the volume percentage of the fiber cloth for the outer skin layer is 35% to 55%, and the volume percentage of the epoxy resin system is The content is 65%-45%; in the epoxy resin system, the addition amount of the curing agent is 30% of the mass of the epoxy resin.

For the above-mentioned composite material for airborne radome, preferably, the inner skin layer material adopts fiber cloth reinforced epoxy resin system composite material; the fiber cloth reinforced epoxy resin system composite material is composed of multiple layers of fiber cloth through It is pasted together; the fiber cloth is one of quartz fiber plain weave, quartz fiber twill and quartz fiber satin weave; the epoxy resin system includes epoxy resin and a curing agent. Further preferably, the epoxy resin is LT5089A, and the curing agent is LT5089B.

For the above-mentioned composite material for airborne radome, preferably, in the inner skin layer, the volume percentage of the fiber cloth for the inner skin layer is 35% to 55%, and the volume percentage of the epoxy resin system is 65%-45%; in the epoxy resin system, the amount of the curing agent added is 30% of the mass of the epoxy resin.

As a general technical concept, the present invention also provides a method for preparing the composite material for the above-mentioned airborne radome, comprising the following steps:

S1. Mix the epoxy resin and the curing agent to prepare an epoxy resin system, use the epoxy resin system as a binder, and use a hand lay-up process to impregnate the multi-layer fiber cloth layer by layer to obtain an inner skin layer prepreg;

S2. Lay the sandwich layer material on the inner skin layer prepreg prepared in step S1, and press;

S3. Using a vacuum bagging method, curing the inner skin layer prepreg at 50-70° C. for 4-6 hours to obtain a sandwich layer-inner skin layer prefabricated body;

S4. Mix the epoxy resin and curing agent to make an epoxy resin system, use the epoxy resin system as a binder, and use a hand lay-up process on the surface of the sandwich layer of the sandwich layer-inner skin layer prefabricated body The outer skin layer prepreg is obtained by impregnating the multi-layer fiber cloth layer by layer;

S5. Using a vacuum bagging method, curing the outer skin layer prepreg at 50-70°C for 4-6 hours to obtain an outer skin layer-sandwich layer-inner skin layer prefabricated body;

S6. Spraying a surface coating on the surface of the outer skin layer of the outer skin layer-sandwich layer-inner skin layer prefabricated body, and then curing to obtain a composite material for an airborne radome.

In the above-mentioned preparation method, preferably, the step S6 specifically includes the following steps:

S6-1. Spray primer glue on the outer surface of the outer skin layer of the outer skin layer-sandwich layer-inner skin layer prefabricated body. After the spraying is completed, dry it at room temperature for 24 hours to form a primer layer;

S6-2. Spray the rain-erosion-resistant paint glue solution on the outer surface of the primer layer, and after the spraying is completed, dry it at room temperature for 2 hours to form a rain-erosion-resistant paint layer;

S6-3. Evenly spray anti-static paint glue on the outer surface of the rain-resistant paint layer. After spraying, dry it at room temperature for 12 hours to form an anti-static paint layer;

S6-4. Curing at 60-80°C for 8-10 hours.

The innovation point of the present invention is:

The airborne radome composite material of the present invention comprises a surface coating, an outer skin layer, a sandwich layer and an inner skin layer, the sandwich layer is arranged between the outer skin layer and the inner skin layer, and the surface coating is coated on the outer skin layer surface. Among them, the outer skin layer and the inner skin layer are the prerequisites for maintaining the structural bearing capacity. The thickness of the outer skin layer is controlled at 0.2-1mm, and the thickness of the inner skin layer is controlled at 0.2-1mm. On the one hand, the bearing capacity is maintained to meet the requirements of the aerodynamic load of the aircraft. Requirements; on the other hand, it can maintain the high wave transmittance of the composite material. The sandwich layer is made of polymethacrylimide foam. While achieving the purpose of strengthening the structure and reducing weight, it can also adjust the phase of the reflected wave reaching the receiving antenna so that the amplitude of the reflected wave of the inner and outer skins is equal. , the phases are opposite, cancel each other out, achieve zero reflection effect, and maintain the transmittance in different wave bands. The actual thickness of the sandwich layer can be designed according to the working conditions of the antenna in the radome and the requirements of wave penetration.

In order to further realize that the radome maintains a high wave transmittance in the dual-band, the present invention designs the thickness of the sandwich layer to be non-uniform and equal in thickness, specifically, the sandwich layer is designed as a right-angled trapezoidal structure. In the actual application process of the radome, the change of the relative position between the antenna and the radome will cause the change of the incident angle of the electromagnetic wave, thereby affecting the wave-transmitting performance of the radome. The change process can meet the wave-transparency performance requirements in different bands. The influence of the radome on the transmission performance of electromagnetic waves is mainly reflected in the absorption and reflection of electromagnetic waves, while the incident angle and wall thickness determine the reflection and transmission ratio of electromagnetic waves, that is, the power transmission characteristics of any radome with selected materials and structural forms (Insertion Loss and Insertion Phase Delay IPD) are both a function of incident angle and thickness. The advantage of sandwich layer application is to select a low-density core layer with a certain thickness. While achieving the purpose of strengthening the structure and reducing weight, it is more important to adjust the phase of the reflected wave reaching the receiving antenna, making zero reflection design possible. In this way, when designing the thickness of the sandwich layer, the optimal core layer thickness can be designed and calculated according to the working conditions of the antenna in the radome, so that the reflected waves of the inner and outer skins have equal amplitudes, opposite phases, and cancel each other out.

Compared with the prior art, the present invention has the advantages of:

(1) The resin-based composite material proposed by the present invention has excellent environmental resistance performance, and can withstand high and low temperature resistance, low air pressure resistance, rain resistance, solar radiation resistance, damp heat resistance, mold resistance, and salt spray resistance through actual test assessment. , Sand and dust resistance, liquid resistance, temperature-humidity-high, anti-static, rain impact and rain erosion and other environmental conditions.

(2) The resin-based composite material proposed by the present invention has a good overall bearing capacity and meets the mechanical environmental load requirements of the airborne radome.

(3) Due to the variable thickness design method of the sandwich layer, the resin-based composite material proposed by the present invention can maintain a high wave transmittance in the dual-wave band, which cannot be realized by the existing technical solutions. In addition, the resin-based composite material of the present invention has a low density, which can effectively reduce the overall weight of the product, thereby increasing the payload ratio of the equipment; the molding process is good and the cost is low. The resin-based composite material of the present invention is a kind of dual-band The material system required for the airborne radome has broad market prospects.

Description of drawings

In order 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 will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

Fig. 1 is a schematic cross-sectional view of a composite material for an airborne radome of the present invention.

Fig. 2 is a photograph of a sample of a composite material for an airborne radome prepared in Example 1 of the present invention.

illustration:

In the accompanying drawings, A ₁ , the antistatic paint layer of the surface coating; A ₂ , the anti-rain erosion paint layer of the surface coating; A ₃ , the primer layer of the surface coating; B, the outer skin layer; Core layer; D, inner skin layer.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

Example

All materials and instruments used in the following examples are commercially available. Among them, the H01-89 epoxy coating as the primer glue, the SF55-49 aliphatic coating as the anti-rain erosion glue, and the SDT99-49 aliphatic coating as the antistatic glue were all purchased from CNOOC Changzhou Paint Chemical Research Institute; LT5089A epoxy resin and LT5089B curing agent were purchased from Huili Resin Co., Ltd.; the PMI foam with the brand name ROHACELL 71IG-F was purchased from Degussa Company in Germany; the brands were B-twill-0.20 and B-twill-0.10 respectively Quartz fiber twill was purchased from Jingzhou Feilihua Quartz Glass Co., Ltd.

Example 1:

A composite material for an airborne radome as shown in Figure 1, which is mainly used to prepare radome working in Ka and Ku bands. Its structure is: a surface coating A, an outer skin layer B, a sandwich layer C, and an inner skin layer D are sequentially arranged from outside to inside, wherein the sandwich layer C is arranged between the outer skin layer B and the inner skin layer D, and the surface coating Layer A is applied to the surface of outer skin layer B.

Wherein the surface coating comprises primer layer A3, anti-rain erosion paint layer A2 and antistatic paint layer A1, rain erosion resistant paint layer A2 is arranged in the middle of primer layer A3 and antistatic paint layer A1, and primer layer A3 is coated on The surface of the outer skin layer B. The thickness of the primer layer is 0.03mm; the thickness of the anti-rain erosion layer is 0.15mm; the thickness of the antistatic layer is 0.04mm.

The outer skin layer uses quartz fiber twill as the reinforcing material for the outer skin layer, and the multi-layer quartz fiber twill cloth is impregnated layer by layer by hand lay-up process to obtain the outer skin layer prepreg. The composition of the epoxy resin glue for the outer skin layer includes LT5089A epoxy resin (purchased from Huili Resin Co., Ltd.) and LT5089B curing agent (purchased from Huili Resin Co., Ltd.) with an amount of 30% of the mass of LT5089A epoxy resin. The fiber volume percentage of the outer skin layer is 45%, and the thickness is 0.5 mm.

The sandwich layer adopts ROHACELL 71IG-F PMI foam (purchased from Degussa, Germany). The PMI foam is processed into a right-angled trapezoid. On the right-angle side opposite to the hypotenuse, the thickness of the short side of the sandwich layer is 15.8 mm, and the thickness of the long side of the sandwich layer is 17.2 mm. The outer skin layer and the inner skin layer are uniform and equal-thick rectangles.

The inner skin layer uses quartz fiber twill as the reinforcing material for the inner skin layer, and the reinforcing material for the inner skin layer is pasted together by the inner skin layer with resin glue to form the inner skin layer. The resin glue solution for the inner skin layer includes LT5089A epoxy resin (purchased from Huili Resin Co., Ltd.) and LT5089B curing agent (purchased from Huili Resin Co., Ltd.) with an amount of 30% of the mass of LT5089A epoxy resin. The inner skin layer has a fiber volume content of 45% and a thickness of 0.5 mm.

The preparation method of the composite material for the airborne radome of the present embodiment specifically comprises the following steps:

1. Preparation of inner skin layer prepreg:

1.1. Preparation of resin glue solution for inner skin layer: prepare LT5089A epoxy resin and LT5089B curing agent, and prepare resin glue solution for inner skin layer according to the ratio of the amount of curing agent to 30% of the resin amount, and set it aside.

1.2. Cutting the reinforcement material of the inner skin layer: according to the shape and size of the sample, cut 2 layers of quartz fiber twill cloth with grade B-twill-0.20 and 1 layer of quartz fiber twill cloth with grade B-twill-0.10, as reinforcement for the inner skin layer Material.

1.3. Hand lay-up impregnation: Spread 1 layer of quartz fiber twill cloth with grade B-twill-0.10 on the male mold, and use the inner skin layer to impregnate evenly with resin glue; then spread 2 layers of grade B-type- The twill-0.20 quartz fiber twill fabric is uniformly impregnated with resin glue solution for each layer of covering to obtain the inner skin layer prepreg, and the fiber volume fraction in the inner skin layer prepreg is controlled to be 45%.

2. Cover the sandwich layer:

Lay the designed and processed PMI foam on the prepreg of the inner skin layer and press it in place.

3. Vacuum bag pressure curing of inner skin layer/sandwich layer:

On the prepreg/sandwich layer of the inner skin layer, the isolation film, the diversion medium and the vacuum bag film are sequentially laid, and cured at 60°C for 4 hours, so that the inner skin layer is cured with the resin glue. After the curing is completed, the vacuum bag film, the diversion medium and the isolation film are removed in sequence, and the surface is trimmed to obtain a sandwich layer-inner skin layer prefabricated body.

4. Prepare the outer skin layer prepreg:

4.1. Prepare the resin glue solution for the outer skin layer: prepare LT5089A epoxy resin and LT5089B curing agent, prepare the resin glue solution for the outer skin layer according to the ratio of the amount of curing agent to 30% of the resin amount, and set it aside.

4.2. Cutting the reinforcement material of the outer skin layer: according to the shape and size of the sample, cut 2 layers of quartz fiber twill cloth with the brand name B-twill-0.20 and 1 layer of quartz fiber twill cloth with the brand name B-twill-0.10 as the outer cover Reinforcement material for cortex.

4.3. Hand lay-up impregnation: Lay 2 layers of quartz fiber twill cloth with grade B-twill-0.20 on the sandwich layer, and use the outer skin layer to impregnate evenly with resin glue for each layer; The layer designation is B-type-twill-0.10 quartz fiber twill cloth to obtain the outer skin layer prepreg, and the fiber volume fraction in the outer skin layer prepreg is controlled to be 45%.

5. Vacuum bag pressure curing of the outer skin layer:

On the prepreg of the outer skin layer, the isolation film, the diversion medium and the vacuum bag film are sequentially cured at 60°C for 4 hours, so that the resin glue solution for the outer skin layer is cured. After the curing is completed, the vacuum bag film, the diversion medium and the isolation film are removed in sequence, the mold is demoulded, and the surface of the outer skin layer is trimmed and polished to obtain the outer skin layer-sandwich layer-inner skin layer prefabricated body.

6. Surface coating preparation:

6.1. Preparation of primer layer: prepare epoxy coating H01-89, and spray evenly on the outer surface of the outer skin layer of the outer skin layer-sandwich layer-inner skin layer prefabricated body. When spraying, control the thickness of the primer layer to 0.03±0.01mm, After spraying, let it dry at room temperature for 24 hours to form a primer layer.

6.2. Preparation of anti-rain erosion paint layer: Prepare aliphatic anti-rain erosion layer coating SF55-49, and spray the anti-rain erosion layer coating evenly on the outer surface of the primer layer. After completion, dry at room temperature for 2 hours to form a rain-corrosion resistant paint layer.

6.3. Preparation of anti-static paint layer: prepare aliphatic anti-static layer coating SDT99-49, and spray anti-static layer coating evenly on the outer surface of rain erosion-resistant layer. When spraying, control the thickness of the anti-static layer to 0.03-0.05mm. After spraying, Dry at room temperature for 12 hours to form an antistatic paint layer.

6.4. Curing: put the whole in an oven, cure at 60°C for 10 hours, and trim the surface to complete the preparation of the composite material for the airborne radome.

The composite material used for the airborne radome in Example 1 was tested for wave transmission performance, and the test results are shown in Table 1.

Table 1: Test results of wave transmission performance of composite materials for airborne radome

It can be seen from the data in Table 1 that the airborne radome composite material prepared in this example maintains high wave transmittance in both Ka and Ku bands, and both wave transmittance and cross-polarization isolation meet the requirements.

The composite material used for the airborne radome in Example 1 was tested for environmental performance, and the test results are shown in Table 2.

Table 2: Environmental performance test results of composite materials for airborne radome

As can be seen from the data in Table 2, the airborne radome composite material of the present invention is resistant to high and low temperature, low air pressure, rain resistance, solar radiation resistance, heat and humidity resistance, mildew resistance, salt spray resistance, and sand and dust resistance. , liquid resistance, temperature-humidity-high, anti-static and other complex environmental conditions, the overall structure has a good bearing capacity.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art, without departing from the spirit and technical solutions of the present invention, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solutions of the present invention, or modify them to be equivalent Variations of equivalent embodiments. Therefore, any simple modifications, equivalent replacements, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solutions of the present invention, still fall within the protection scope of the technical solutions of the present invention.

Claims (9)

1. a composite material for airborne radome, is characterized in that, comprises surface coating, outer skin layer, sandwich layer and inner skin layer, and described sandwich layer is sandwiched between outer skin layer and inner skin layer, so The surface coating is coated on the surface of the outer skin layer; the thickness of the outer skin layer is 0.2-1 mm; the thickness of the inner skin layer is 0.2-1 mm; the sandwich layer is polymethacrylimide A right-angled trapezoid made of foam, the outer skin layer is arranged on the hypotenuse of the sandwich layer, the inner skin layer is arranged on the right-angle side opposite to the hypotenuse of the sandwich layer, and the thickness of the short side of the sandwich layer is 4-30 mm, the thickness of the long side of the sandwich layer is 0.5-4 mm thicker than the short side; the outer skin layer and the inner skin layer are rectangles with uniform thickness. 2. The composite material for airborne radome according to claim 1, wherein the surface coating comprises a primer layer, a rain-erosion-resistant paint layer and an antistatic paint layer, and the rain-erosion-resistant paint layer is provided with Between the primer layer and the antistatic paint layer, the primer layer is coated on the surface of the outer skin layer. 3. airborne radome composite material according to claim 2, is characterized in that, the material of described priming paint layer is H01-89, and thickness is 0.03 ± 0.01mm; The material of described rain erosion-resistant paint layer is SF55-49, the thickness is 0.15±0.02mm; the material of the antistatic paint layer is SDT99-49, the thickness is 0.03-0.05mm. 4. composite material for airborne radome according to claim 1, is characterized in that, described outer skin layer adopts fiber cloth to strengthen epoxy resin system composite material; Described fiber cloth strengthens epoxy resin system composite material by multiple Layers of fiber cloth are bonded by an epoxy resin system; the fiber cloth is one of quartz fiber plain weave, quartz fiber twill and quartz fiber satin weave; the epoxy resin system includes epoxy resin and a curing agent. 5. The composite material for airborne radome according to claim 4, characterized in that, in the outer skin layer, the volume percentage of the fiber cloth is 35% to 55%, and the epoxy resin system The volume percentage content is 65%-45%; in the epoxy resin system, the addition amount of the curing agent is 30% of the mass of the epoxy resin. 6. The composite material for an airborne radome according to claim 1, wherein the inner skin layer material adopts a fiber cloth reinforced epoxy resin system composite material; the fiber cloth reinforced epoxy resin system composite material is composed of multiple Layers of fiber cloth are pasted by an epoxy resin system; the fiber cloth is one of quartz fiber plain weave, quartz fiber twill and quartz fiber satin weave; the epoxy resin system includes epoxy resin and a curing agent. 7. The composite material for airborne radome according to claim 6, characterized in that, in the inner skin layer, the volume percentage of the fiber cloth is 35% to 55%, and the epoxy resin system The volume percentage is 65%-45%; in the epoxy resin system, the addition amount of the curing agent is 30% of the mass of the epoxy resin. 8. A method for preparing a composite material for an airborne radome according to any one of claims 1 to 7, characterized in that, comprising the following steps: S1. Mix the epoxy resin and the curing agent to prepare an epoxy resin system, use the epoxy resin system as a binder, and use a hand lay-up process to impregnate the multi-layer fiber cloth layer by layer to obtain an inner skin layer prepreg; S2. Lay the sandwich layer material on the inner skin layer prepreg prepared in step S1, and press; S3. Using a vacuum bagging method, curing the inner skin layer prepreg at 50-70° C. for 4-6 hours to obtain a sandwich layer-inner skin layer prefabricated body; S4. Mix the epoxy resin and curing agent to make an epoxy resin system, use the epoxy resin system as a binder, and use a hand lay-up process on the surface of the sandwich layer of the sandwich layer-inner skin layer prefabricated body The outer skin layer prepreg is obtained by impregnating the multi-layer fiber cloth layer by layer; S5. Using a vacuum bagging method, curing the outer skin layer prepreg at 50-70°C for 4-6 hours to obtain an outer skin layer-sandwich layer-inner skin layer prefabricated body; S6. Spraying a surface coating on the surface of the outer skin layer of the outer skin layer-sandwich layer-inner skin layer prefabricated body, and then curing to obtain a composite material for an airborne radome. 9. The preparation method according to claim 8, wherein said step S6 specifically comprises the following steps: S6-1. Spray primer glue on the outer surface of the outer skin layer of the outer skin layer-sandwich layer-inner skin layer prefabricated body. After the spraying is completed, dry it at room temperature for 24 hours to form a primer layer; S6-2. Spray the rain-erosion-resistant paint glue solution on the outer surface of the primer layer, and after the spraying is completed, dry it at room temperature for 2 hours to form a rain-erosion-resistant paint layer; S6-3. Evenly spray anti-static paint glue on the outer surface of the rain-resistant paint layer. After spraying, dry it at room temperature for 12 hours to form an anti-static paint layer; S6-4. Curing at 60-80°C for 8-10 hours.