Radar-transparent composite panels and radomes and methods of manufacture

Abstract

The application provides a wave-transparent composite material panel, a radar cover and a manufacturing method. The wave-transparent composite material panel comprises a structure layer, a wave-transparent layer and a protective layer wrapped outside the structure layer and the wave-transparent layer, wherein the structure layer comprises at least two foam layers, the wave-transparent layer comprises at least two hollow fabric composite material layers, the two adjacent foam layers and the two adjacent hollow fabric composite material layers are spaced apart by the protective layer, the reinforcing body of the hollow fabric composite material layer is woven by glass fiber yarn, and the protective layer is formed by laying glass fiber cloth first and then pouring resin. The wave-transparent composite material panel can ensure the mechanical property and the wave-transparent property simultaneously.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and in particular to a wave-transparent composite material panel, a radome, and a method for manufacturing it. Background Technology

[0002] As a window to electromagnetic waves, radomes are a crucial component of communication systems in high-end equipment such as aerospace and naval vessels. They prevent external factors from affecting and interfering with antennas or related radio frequency equipment, improving system stability and reliability, and extending equipment lifespan. The performance of radomes has a significant impact on the functionality of high-end equipment communication systems.

[0003] Typically, radomes need to meet high wave transmittance requirements to ensure the normal transmission of electromagnetic signals. They also need excellent mechanical load-bearing capacity. However, it's difficult to simultaneously improve both the mechanical properties and wave transmittance of a radome structure. For example, increasing the radome wall thickness can improve structural stiffness, but it also increases electromagnetic wave propagation loss. Furthermore, functional layers are incorporated into the radome structure to control electromagnetic waves, such as frequency selective surface (FSS) materials. While FSS can improve the structure's electromagnetic capabilities, it also weakens the radome's interfacial mechanical properties, resulting in poor structural mechanical performance. Summary of the Invention

[0004] The main objective of this invention is to provide a wave-transparent composite material panel and radome, as well as a manufacturing method, which aims to simultaneously ensure its mechanical properties and wave-transparent properties.

[0005] To achieve the above objectives, the present invention provides a wave-transparent composite material panel, comprising a structural layer, a wave-transparent layer, and a protective layer surrounding the structural layer and the wave-transparent layer, wherein... The structural layer includes at least two foam layers, and the wave-transparent layer includes at least two hollow fabric composite material layers. Adjacent foam layers and hollow fabric composite material layers are separated by a protective layer. The reinforcement of the hollow fabric composite material layer is made of glass fiber yarn, and the protective layer is formed by first laying glass fiber cloth and then injecting resin.

[0006] Preferably, the thickness of the structural layer is greater than the thickness of the wave-transparent layer, the number of foam layers is greater than the number of hollow fabric composite material layers, and one end face of the wave-transparent layer forms a concave structure relative to the structural layer due to its reduced height for wave transmission.

[0007] Preferably, the top surface of the foam layer and the wave-transparent layer is the end surface of the wave-transparent layer with a concave structure, and the top surface of the foam layer has reinforcing ribs.

[0008] Preferably, the reinforcing rib is made by laying glass fiber cloth and then injecting resin.

[0009] Preferably, the hollow fabric composite material layer, the protective layer, and the reinforcing ribs are formed using a co-curing method.

[0010] Preferably, the top, bottom, and sidewalls of the structural layer and the wave-transparent layer are all wrapped with fiberglass cloth.

[0011] Preferably, the sidewalls of the hollow fabric composite layer and the foam layer, which are at the same height, are fixedly connected.

[0012] Preferably, the sidewalls of the hollow fabric composite material layer and the foam layer are fixed by adhesive bonding, and the foam layer is made of polyethylene terephthalate.

[0013] The present invention further proposes a radar dome comprising the aforementioned wave-transparent composite material panel.

[0014] This invention also proposes a method for manufacturing a wave-transparent composite material panel based on the above-mentioned material, comprising the following steps: A single-layer hollow fabric composite material layer was prepared using a vacuum flow method, and the hollow fabric composite material layer was cut into appropriate sizes according to actual needs. Multiple foam layers are fabricated and the sidewalls of the foam layers to be bonded are bonded to the hollow fabric composite material layer of the same height as a whole. The fiberglass cloth, single foam layer, foam layer and hollow fabric composite material layer are bonded together and laid on the mold in the order of the structural arrangement. Resin is injected into the mold using a vacuum flow method, and the preform is co-cured and molded using a vacuum bag press.

[0015] The wave-transmitting composite material panel proposed in this invention has the following beneficial effects: 1. By combining a foam layer with a wave-transparent composite panel and an external protective layer, the energy absorption characteristics of the wave-transparent layer reduce the magnitude of the impact load on the structure. The discrete core layer of the hollow fabric composite material layer reduces the medium loss of electromagnetic wave propagation and ensures that the structure has a high wave transmittance. In other words, it improves the structural performance and impact resistance on the one hand, and improves the wave transmittance performance on the other hand. 2. This composite material panel has the advantages of structural stability and ease of implementation; 3. Compared with the traditional sandwich composite material structure, the impact resistance of this composite material panel is improved by 15% and the wave transmission performance is improved by 10%. Attached Figure Description

[0016] Figure 1 This is a cross-sectional structural schematic diagram of the first embodiment of the wave-transparent composite material panel of the present invention; Figure 2This is a three-dimensional structural schematic diagram of the first embodiment of the wave-transparent composite material panel of the present invention; Figure 3 This is a cross-sectional structural schematic diagram of a second embodiment of the wave-transparent composite material panel of the present invention; Figure 4 This is a three-dimensional structural schematic diagram of a second embodiment of the wave-transparent composite material panel of the present invention; Figure 5 This is a schematic flowchart illustrating the method for manufacturing the wave-transparent composite material panel of the present invention.

[0017] In the diagram, 1-foam layer, 2-hollow fabric composite material layer, 3-protective layer, 4-reinforcing rib, 5-concave structure.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] It should be noted that in the description of this invention, the terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] This invention proposes a wave-transparent composite material panel.

[0022] Reference Figure 1 and Figure 2 This invention proposes a first embodiment of a wave-transparent composite material panel. In this embodiment, the wave-transparent composite material panel includes a structural layer, a wave-transparent layer, and a protective layer 3 wrapped around the structural layer and the wave-transparent layer. The structural layer includes at least two foam layers 1, and the wave-transparent layer includes at least two hollow fabric composite material layers 2. The two adjacent foam layers 1 and the two hollow fabric composite material layers 2 are separated by a protective layer 3. The reinforcement of the hollow fabric composite material layer 2 is made of glass fiber yarn, and the protective layer 3 is formed by first laying glass fiber cloth and then injecting resin.

[0023] The wave-transmitting layer consists of at least two hollow fabric composite material layers 2. The reinforcement of the hollow fabric composite material layer 2 is made of glass fiber yarn. Therefore, the hollow fabric composite material layer 2 is discrete, which can reduce the dielectric loss during electromagnetic wave propagation and ensure a high wave transmittance.

[0024] Specifically, the thickness of the structural layer is greater than the thickness of the wave-transmitting layer, the number of layers of the foam layer 1 is greater than the number of layers of the hollow fabric composite material layer 2, and one end face of the wave-transmitting layer forms a concave structure 5 due to the reduced height relative to the structural layer for wave transmission.

[0025] By increasing the thickness of the structural layer to be greater than that of the wave-transparent layer, the increased thickness of the structural layer reduces deformation and mitigates damage caused by shock waves.

[0026] Specifically, in this embodiment, the top surface of the foam layer 1 and the wave-transparent layer is the end surface of the wave-transparent layer with the concave structure 5, and the top surface of the foam layer 1 has reinforcing ribs 4 formed thereon. Specifically, the foam layer 1, which is larger than the hollow fabric composite layer 2, is placed on the top surface of the structural layer and then wrapped with a protective layer 3, thus naturally forming the concave structure 5.

[0027] In this embodiment, refer to Figure 1 It is set in a single-opening form, in which the wave-transparent layer is placed in the central area of ​​the structural layer, and the reinforcing ribs 4 are arranged around the wave-transparent layer.

[0028] By arranging reinforcing ribs 4 on the panel ( Figure 2 (The stiffener 4 is not shown in the figure) improves the overall rigidity of the structure, reduces deformation, and mitigates damage caused by impact.

[0029] Specifically, the reinforcing rib 4 is formed by laying fiberglass cloth and injecting resin. Therefore, the reinforcing rib 4 can be integrally formed with the protective layer 3. This arrangement improves the overall structural strength (the resin of the reinforcing rib 4 and the protective layer 3 are injected together, resulting in high bonding strength) and simplifies the overall manufacturing process.

[0030] In this embodiment, the hollow fabric composite material layer 2, the protective layer 3, and the reinforcing rib 4 are formed by co-curing. This means that the protective layer 3 and the reinforcing rib 4 are first laid with glass fiber cloth and then injected with resin. During the resin curing process, since the protective layer 3 located between the structural layer and the wave-transparent layer is connected to both the upper and lower layers, the resin hardens during the resin injection process, thereby bonding the middle protective layer 3 and the upper and lower structural layers and wave-transparent layers into a whole.

[0031] The co-curing method ensures interfacial shear strength and enhances the impact resistance of the structure. On the other hand, this molding process is simple to operate, has low preparation cost, and can be mass-produced.

[0032] Furthermore, the top, bottom, and sidewalls of the structural layer and the wave-transparent layer are all wrapped with fiberglass cloth, thereby further improving the structural strength of the wave-transparent composite panel.

[0033] Furthermore, the sidewalls of the hollow fabric composite layer 2 and the foam layer 1, which are located at the same height, are fixedly connected. Specifically, in this embodiment, the sidewalls of the hollow fabric composite layer 2 and the foam layer 1 are fixed by adhesive bonding, and the foam layer 1 is made of polyethylene terephthalate.

[0034] The manufacturing process of the wave-transparent composite panel is illustrated below, taking three layers of foam as an example: (1) A single-layer hollow fabric composite material layer 2 was prepared by injecting resin liquid using the vacuum diversion method, and then cut into appropriate sizes according to actual needs. (2) Cut a portion of the foam to the same thickness as the hollow fabric composite layer 2 in step (1) (there are two layers), and make openings to facilitate the flow of subsequent resin. (3) Apply an appropriate amount of high-strength structural adhesive evenly to the interface between the hollow fabric composite material layer 2 and the foam layer 1, which are in the same layer, and bond the two together as a whole. (4) Cut the fiberglass cloth required for the protective layer 3 and the reinforcing rib 4 according to actual needs; (5) Combine the glass fiber cloth from step (4) and the hollow fabric composite material layer 2 and foam layer 1 formed in step (3) as a whole, and partially combine the single-layer foam layer 1 according to... Figure 1 As shown, they are laid sequentially on the mold to form a preform; (6) The resin liquid is injected into the mold in step (5) using the vacuum diversion method; (7) The preform obtained in step (5) is co-cured and molded by vacuum bag pressing to obtain a composite material panel preform; (8) Post-process the composite material panel preform obtained in step (7) to obtain a composite material structural component.

[0035] The wave-transparent composite material panel proposed in this embodiment has the following beneficial effects: 1. By combining the foam layer 1 and the wave-transparent composite material panel, and with the outer protective layer 3, the energy absorption characteristics of the wave-transparent layer reduce the magnitude of the impact load on the structure. The discrete core layer of the hollow fabric composite material layer 2 can reduce the medium loss of electromagnetic wave propagation and ensure that the structure has a high wave transmittance. In other words, on the one hand, the structural performance and impact resistance are improved, and on the other hand, the wave transmittance performance is improved. 2. This composite material panel has the advantages of structural stability and ease of implementation; 3. Compared with the traditional sandwich composite material structure, the impact resistance of this composite material panel is improved by 15% and the wave transmission performance is improved by 10%.

[0036] Reference Figure 3 and Figure 4 This invention proposes a second embodiment of a wave-transparent composite material panel. This embodiment differs from the first embodiment in that the concave regions formed by the wave-transparent area create a group of openings, the wave-transparent layer forms multiple concave regions, and the reinforcing ribs 4 have a cross-shaped structure.

[0037] The present invention also proposes a radar dome.

[0038] In this preferred embodiment, a radome includes a wave-transparent composite material panel. The specific structure and beneficial effects of the wave-transparent composite material panel are the same as in the above embodiments and will not be repeated here.

[0039] The present invention further proposes a method for manufacturing a wave-transparent composite material panel.

[0040] Reference Figure 5 In this preferred embodiment, a method for manufacturing a wave-transparent composite material panel includes the following steps: Step S10: Prepare a single-layer hollow fabric composite material layer 2 using the vacuum flow method, and cut the hollow fabric composite material layer 2 into appropriate sizes according to actual needs; Step S20: Make multiple foam layers 1 and bond the sidewall of the foam layer 1 that needs to be bonded (taking three foam layers as an example, at this time, two foam layers need to be bonded and one foam layer does not need to be bonded) to the hollow fabric composite material layer 2 of the same height as the whole. Step S30: The whole structure formed by bonding the fiberglass cloth, the single foam layer 1, the foam layer 1 and the hollow fabric composite material layer 2 is laid on the mold in the order of the structural arrangement. In step S40, resin is injected into the mold using a vacuum flow method, and the preform is co-cured and molded using a vacuum bag press.

[0041] When preparing a single-layer hollow fabric composite material layer using the vacuum flow method, the fabric is first made by machine weaving glass fiber yarn, and then filled with a single-layer hollow fabric composite material layer of resin-molded solid for subsequent bonding and fixation with the foam layer.

[0042] In step S30, three layers of foam layer 1 and two layers of hollow fabric composite material layer 2 are provided. The specific laying process is as follows: First, fiberglass cloth is laid at the bottom to form the bottom protective layer 3 (first protective layer 3). During the laying process, fiberglass cloth on both sides can be reserved to wrap the sides of foam layer 1 and wave-transparent layer, further improving the overall structural stability. After the bottom fiberglass cloth is laid, a layer of foam layer 1 and hollow fabric composite material layer 2 bonded together is placed on top. Then, fiberglass cloth is laid on top of the whole to form the second protective layer 3. After placing a layer of foam layer 1 and hollow fabric composite material layer 2 bonded together on top of the second protective layer 3, fiberglass cloth is laid on top of the whole to form the third protective layer 3. Foam layer 1 is placed on both sides above the third protective layer 3. Finally, fiberglass cloth is laid on top of the top foam layer 1 to form the fourth protective layer 3.

[0043] The manufacturing method proposed in this invention uses vacuum flow and vacuum bag compression to co-cur the preform, which can ensure the interfacial shear strength and enhance the explosion and impact resistance of the structure. This manufacturing method is simple to operate, has low preparation cost, and can be mass-produced.

[0044] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A wave-transparent composite material panel, characterized in that, It includes a structural layer, a wave-transparent layer, and a protective layer surrounding the structural layer and the wave-transparent layer, wherein, The structural layer includes at least two foam layers, and the wave-transparent layer includes at least two hollow fabric composite material layers. Adjacent foam layers and hollow fabric composite material layers are separated by protective layers. The reinforcement of the hollow fabric composite material layers is made of glass fiber yarn, and the protective layer is formed by first laying glass fiber cloth and then injecting resin.

2. The wave-transparent composite material panel as described in claim 1, characterized in that, The thickness of the structural layer is greater than the thickness of the wave-transparent layer, the number of foam layers is greater than the number of hollow fabric composite material layers, and one end face of the wave-transparent layer forms a concave structure due to the reduced height relative to the structural layer for wave transmission.

3. The wave-transparent composite material panel as described in claim 2, characterized in that, The top surfaces of the foam layer and the wave-transparent layer are such that the wave-transparent layer has a concave structure, and the top surface of the foam layer has reinforcing ribs.

4. The wave-transparent composite material panel as described in claim 3, characterized in that, The reinforcing ribs are made by laying fiberglass cloth and then injecting resin.

5. The wave-transparent composite material panel as described in claim 4, characterized in that, The hollow fabric composite material layer, protective layer, and reinforcing ribs are formed using a co-curing method.

6. The wave-transparent composite material panel as described in any one of claims 1 to 5, characterized in that, The top, bottom, and sidewalls of the structural layer and the wave-transparent layer are all wrapped with fiberglass cloth.

7. The wave-transparent composite material panel as described in claim 2, characterized in that, The sidewalls of the hollow fabric composite layer and the foam layer, which are located at the same height, are fixedly connected.

8. The wave-transparent composite material panel as described in claim 7, characterized in that, The sidewalls of the hollow fabric composite material layer and the foam layer are fixed by adhesive bonding, and the foam layer is made of polyethylene terephthalate.

9. A radar dome, characterized in that, Including the wave-transparent composite material panel as described in any one of claims 1 to 8.

10. A method for manufacturing a wave-transparent composite material panel according to any one of claims 1 to 8, characterized in that, Includes the following steps: A single-layer hollow fabric composite material layer was prepared using a vacuum flow method, and the hollow fabric composite material layer was cut into appropriate sizes according to actual needs. Multiple foam layers are fabricated and the sidewalls of the foam layers to be bonded are bonded to the hollow fabric composite material layer of the same height as a whole. The fiberglass cloth, single foam layer, foam layer and hollow fabric composite material layer are bonded together and laid on the mold in the order of the structural arrangement. Resin is injected into the mold using a vacuum flow method, and the preform is co-cured and molded using a vacuum bag press.

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