Antenna cover top high bearing roof and forming method

Abstract

The application provides a high-load top plate for a radome top and a forming method, and belongs to the field of wireless communication.The application solves the problems of low strength, poor electromagnetic transmission performance and large weight of the existing radome top plate.The high-load top plate comprises a top plate body, the top plate body is a C sandwich structure, the top plate body is formed by resin infiltration and solidification, the top plate body comprises a first inner skin, a second inner skin, a first middle skin, a second middle skin, an outer skin, outer skin chopped felt and inner skin chopped felt, the outer skin chopped felt, the outer skin, the first middle skin, the second middle skin, the first inner skin, the second inner skin and the inner skin chopped felt are sequentially arranged layer by layer from top to bottom, three-dimensional fabric is arranged between the outer skin and the first middle skin and between the second middle skin and the first inner skin, and the three-dimensional fabric is formed by a thermosetting resin vacuum-assisted forming.The high-load top plate is mainly used for the radome top.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication, and in particular relates to a high load-bearing top plate for the antenna radome and a method for forming it. Background Technology

[0002] Radar radomes are indispensable protective devices for radar antennas. To facilitate radome assembly and maintenance, radomes with a diameter of 7 meters or more are generally equipped with top suspension points. These suspension points are located at the base of the lightning rod and aviation obstruction light on the top of the radome, with a top plate load-bearing capacity of 100 kg. This meets the usage requirements of professional installation and maintenance personnel from domestic manufacturers. Radomes exported to Europe must meet the safety requirements of European standard EN795. This standard requires that the static load-bearing capacity of the fixed anchor points be within the range of 10 kN to 30 kN. However, existing radome top plates have low strength and poor electromagnetic transmission performance. Moreover, the use of a solid fiberglass structure for the top plate results in a large plate weight, which cannot meet the safety risk prevention requirements of foreign maintenance personnel during operation. Summary of the Invention

[0003] In view of this, the present invention aims to provide a high load-bearing top plate for radomes and a forming method thereof, in order to solve the problems of low strength, poor electromagnetic transmission performance and large weight of existing radome top plates.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a high-load-bearing top plate for an antenna radome, comprising a top plate body, wherein the top plate body has a C-layer structure and is formed by resin impregnation and curing. The top plate body comprises a first inner skin, a second inner skin, a first middle skin, a second middle skin, an outer skin, an outer skin chopped strand mat, and an inner skin chopped strand mat. The outer skin chopped strand mat, outer skin, first middle skin, second middle skin, first inner skin, second inner skin, and inner skin chopped strand mat are arranged sequentially from top to bottom. Three-dimensional fabrics are sandwiched between the outer skin and the first middle skin, and between the second middle skin and the first inner skin. The three-dimensional fabrics comprise multiple fiber layers arranged sequentially from top to bottom. Each pair of adjacent fiber layers is connected by multiple fiber core columns. The radial direction of the fiber core columns is in the shape of an "8" and the weft direction is in the shape of a "1". The three-dimensional fabrics are vacuum-assisted molded from thermosetting resin.

[0005] Furthermore, the first inner skin comprises two layers of EWR400 fabric arranged sequentially from top to bottom, and the second inner skin comprises eight layers of EWR400 fabric and two layers of EWR200 fabric arranged sequentially from top to bottom.

[0006] Furthermore, the first inner skin comprises three layers of EWR400 fabric arranged sequentially from top to bottom, and the second inner skin comprises two layers of EWR400 fabric arranged sequentially from top to bottom.

[0007] Furthermore, the outer skin comprises two layers of EWR200 fabric and eight layers of EWR400 fabric arranged sequentially from top to bottom.

[0008] Furthermore, the top plate is equipped with a ventilation duct.

[0009] Furthermore, the top of the top plate is provided with multiple lifting rings, which are symmetrically arranged on both sides of the ventilation duct.

[0010] Furthermore, a short ladder is provided at the bottom of the top plate, and the top of the short ladder is connected to the ventilation duct.

[0011] Furthermore, both the outer and inner chopped strand mats are covered with gel coat.

[0012] The present invention also provides a method for forming a high load-bearing top plate on the top of an antenna radome, which includes the following steps:

[0013] Step 1: Spray gel coat onto the surface of the female mold, and then heat the mold to accelerate the curing speed of the gel coat;

[0014] Step 2: After the gel coat has cured, lay the outer skin chopped strand mat on the gel coat surface, then impregnate the first chopped strand mat with resin, and then lay the two layers of EWR200 fabric and eight layers of EWR400 fabric of the outer skin in sequence according to the layering structure, and impregnate them with resin.

[0015] Step 3: Lay the three-dimensional fabric on the impregnated outer skin, then lay the two layers of EWR400 fabric of the first middle skin on the three-dimensional fabric in sequence, then use a vacuum pump to vacuum the three-dimensional fabric and simultaneously introduce resin. After the resin has fully impregnated the three-dimensional fabric and the first middle skin, turn off the vacuum pump and allow the three-dimensional fabric to expand naturally to the specified thickness and cure naturally.

[0016] Step 4: After curing, use a flat mold to sand and roughen the first inner skin. After sanding and roughening, lay the three layers of EWR400 fabric of the second inner skin on the first inner skin and impregnate it with resin. Then lay the second layer of three-dimensional fabric on the impregnated second inner skin. Then lay the two layers of EWR400 fabric of the first inner skin on the second layer of three-dimensional fabric. Then use a vacuum pump to vacuum the second layer of three-dimensional fabric and simultaneously introduce resin. After the resin has fully impregnated the three-dimensional fabric and the first inner skin, turn off the vacuum pump and allow the three-dimensional fabric to expand naturally to the specified thickness and cure naturally. After curing, sand and roughen the first inner skin.

[0017] Step 5: Spray gel coat onto the male mold, and then heat the mold to accelerate the curing speed of the gel coat;

[0018] Step 6: Lay the inner lining chopped strand mat and the two layers of EWR200 fabric of the second inner lining onto the positive mold in the order of the layup structure, and impregnate them with resin. At the same time, lay the eight layers of EWR400 fabric of the second inner lining onto the sanded and roughened product of the negative mold in the order of the layup structure, and impregnate them with resin.

[0019] Step 7: Then, the male mold and female mold are joined together, the mold is introduced and vacuumed to form the shape. After curing, the top plate is demolded and trimmed to complete the forming of the top plate.

[0020] Step 8: After the top plate is formed, complete the assembly of the top plate, lifting rings, short ladder and ventilation duct.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. The top plate of the present invention adopts a C-layer structure and uses three-dimensional fabric as the core material, which has extraordinary anti-peel performance, durability and excellent integrity, enhances the strength of the antenna radome top plate, has strong electromagnetic transmission performance, improves the load-bearing capacity of the antenna radome top plate, and effectively reduces the weight of the antenna radome top plate.

[0023] 2. In this invention, the fiber layers of the three-dimensional fabric are connected by fiber core pillars, which gives the three-dimensional fabric internal stress. Furthermore, through the capillary principle of glass fiber yarn, the resin penetration speed is fast, avoiding concentrated resin curing. Moreover, the compressive strength of the three-dimensional fabric is higher than that of polyurethane foam, PVC and other core materials, and it is lighter in weight. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 This is a schematic diagram of the overall structure of the high load-bearing top plate of the antenna radome according to the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the top plate of the high load-bearing top plate of the antenna radome according to the present invention;

[0027] Figure 3 This is a three-dimensional structural diagram of a three-dimensional fabric for a high-load-bearing top plate of an antenna radome according to the present invention.

[0028] Figure 4 This is a schematic diagram of the lifting ring structure of the high load-bearing top plate of the antenna radome according to the present invention;

[0029] Figure 5This is a schematic diagram of radial stress analysis of the top plate of a high load-bearing top plate of an antenna radome according to the present invention;

[0030] Figure 6 This is a schematic diagram of the latitudinal stress analysis of the top plate of the high load-bearing top plate of the antenna radome according to the present invention;

[0031] Figure 7 This is a schematic diagram of the stress analysis in the XY direction of the top plate of the high load-bearing top plate of the antenna radome according to the present invention.

[0032] 1-Top plate, 101-Outer skin, 102-Three-dimensional fabric, 103-First middle skin, 104-Second middle skin, 105-First inner skin, 106-Second inner skin, 2-Ventilation duct, 3-Short ladder, 4-Lifting ring. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0034] See Figure 1-7 This embodiment describes a high-load-bearing top plate for an antenna radome. It includes a top plate body 1, which has a C-layer structure and is formed by resin impregnation and curing. The top plate body 1 includes a first inner skin 105, a second inner skin 106, a first middle skin 103, a second middle skin 104, an outer skin 101, chopped strand mat for the outer skin 101, and chopped strand mat for the inner skin. The second inner skin 106 and the inner skin chopped strand mat are arranged layer by layer from top to bottom. A three-dimensional fabric 102 is sandwiched between the outer skin 101 and the first middle skin 103, and between the second middle skin 104 and the first inner skin 105. The three-dimensional fabric 102 includes multiple fiber layers arranged layer by layer from top to bottom. Each pair of adjacent fiber layers is connected by multiple fiber cores. The fiber cores are shaped like an "8" in the radial direction and "1" in the weft direction. The three-dimensional fabric 102 is vacuum-assisted molded from thermosetting resin.

[0035] In this embodiment, the top plate 1 of the high-load-bearing radome adopts a C-layer structure and uses three-dimensional fabric 102 as the core material. This fabric possesses exceptional peel resistance, durability, and excellent overall integrity, enhancing the strength of the radome top plate and providing strong electromagnetic permeability. This increases the load-bearing capacity of the radome top plate to 1500 kg, effectively reducing the overall weight of the radome top plate. The fiber layers of the three-dimensional fabric 102 are connected by continuous fiber core pillars, forming a sandwich material structure. The core pillars between the layers are radially arranged in an "8" shape. The integral fiberglass three-dimensional fabric with a weft-shaped "1" shape gives the three-dimensional fabric 102 internal stress. Furthermore, through the capillary principle of fiberglass yarn, the resin penetration speed is fast, avoiding resin curing concentration. Moreover, the compressive strength of the three-dimensional fabric 102 is higher than that of polyurethane foam, PVC and other core materials, and it is lighter. Through test, the compressive strength of the fiberglass board made of the three-dimensional fabric with a thickness of 12mm is 0.90MPa, while the compressive strength of the polyurethane foam board with a thickness of 30mm is 0.35MPa. It can be seen that the fiberglass board made of the three-dimensional fabric 102 has better resistance.

[0036] In this embodiment, the first inner skin 105 includes two layers of EWR400 fabric arranged sequentially from top to bottom, and the second inner skin 106 includes eight layers of EWR400 fabric and two layers of EWR200 fabric arranged sequentially from top to bottom.

[0037] In this embodiment, the first middle skin 103 includes three layers of EWR400 fabric arranged sequentially from top to bottom, and the second middle skin 104 includes two layers of EWR400 fabric arranged sequentially from top to bottom.

[0038] In this embodiment, the outer skin 101 includes two layers of EWR200 fabric and eight layers of EWR400 fabric arranged sequentially from top to bottom.

[0039] In this embodiment, a three-dimensional fabric 102 is used as the core material, and a fiberglass plate composed of high-strength fiberglass cloth as the skin material and resin is used as the top plate 1. The plate weighs 150 kg and has a load-bearing capacity of 1500 kg. The analytical diagrams of the radial stress, weft stress, and XY stress of the top plate 1 are shown below. Figure 5 , Figure 6 as well as Figure 7 As shown.

[0040] In this embodiment, the top plate 1 is provided with a ventilation duct 2. The ventilation duct facilitates the maintenance and upkeep of the high load-bearing top plate of the antenna cover and other external devices by the staff.

[0041] In this embodiment, the top of the top plate 1 is provided with multiple lifting rings 4. The multiple lifting rings 4 are symmetrically arranged on both sides of the ventilation duct 2. The lifting rings are connected to safety ropes, which play a protective role when workers perform maintenance and upkeep on the high load-bearing top plate of the antenna cover and other external devices.

[0042] In this embodiment, a short ladder 3 is provided at the bottom of the top plate 1. The top of the short ladder 3 is connected to the ventilation duct 2. The short ladder facilitates workers to ascend to the high load-bearing top plate of the antenna cover for work. The short ladder can also be connected to a long ladder as needed.

[0043] In this embodiment, both the outer and inner chopped strand mats are covered with gel coat.

[0044] This embodiment also provides a method for forming a high load-bearing top plate on the radome, which includes the following steps:

[0045] Step 1: Spray gel coat onto the surface of the female mold, and then heat the mold to accelerate the curing speed of the gel coat;

[0046] Step 2: After the gel coat has cured, lay the outer skin 101 chopped strand mat on the gel coat surface, then impregnate the first chopped strand mat with resin, and then lay the two layers of EWR200 cloth and eight layers of EWR400 cloth of the outer skin 101 in sequence according to the layering structure, and impregnate them with resin.

[0047] Step 3: Lay the three-dimensional fabric 102 on the impregnated outer skin 101, then lay the two layers of EWR400 fabric of the first middle skin 103 on the three-dimensional fabric 102 in sequence. Then use a vacuum pump to vacuum the three-dimensional fabric 102 and simultaneously introduce resin. After the resin has fully impregnated the three-dimensional fabric 102 and the first middle skin 103, turn off the vacuum pump and allow the three-dimensional fabric 102 to expand naturally to the specified thickness and cure naturally.

[0048] Step 4: After curing, use a flat mold to sand and roughen the first middle skin 103. After sanding and roughening, place the three layers of EWR400 fabric of the second middle skin 104 on the first middle skin 103 and impregnate it with resin. Then, place the second layer of three-dimensional fabric 102 on the impregnated second middle skin 104. Then, place the two layers of EWR400 fabric of the first inner skin 105 on the second layer of three-dimensional fabric 102. Then, use a vacuum pump to vacuum the second layer of three-dimensional fabric 102 and simultaneously introduce resin. After the resin has fully impregnated the three-dimensional fabric 102 and the first inner skin 105, turn off the vacuum pump and allow the three-dimensional fabric 102 to expand naturally to the specified thickness and cure naturally. After curing, sand and roughen the first inner skin 105.

[0049] Step 5: Spray gel coat onto the male mold, and then heat the mold to accelerate the curing speed of the gel coat;

[0050] Step 6: Lay the inner lining chopped strand mat and the two layers of EWR200 fabric of the second inner lining 106 onto the positive mold in the order of the layup structure, and impregnate them with resin. At the same time, lay the eight layers of EWR400 fabric of the second inner lining 106 onto the product of the negative mold that has been sanded and roughened in the order of the layup structure, and impregnate them with resin.

[0051] Step 7: Then, the male mold and female mold are joined together, the mold is introduced and vacuumed to form the shape. After curing, the mold is demolded and the edges are trimmed to complete the forming of the top plate 1.

[0052] Step 8: After the top plate 1 is formed, complete the assembly of the top plate 1, the lifting ring 4, the short ladder 3 and the ventilation duct 2.

[0053] This embodiment uses a wet molding process.

[0054] In this embodiment, the outer skin 101, the first inner skin 105, and the second inner skin 106 are made of chopped strand mat made of glass fiber cloth and naturally cured with unsaturated polyester resin.

[0055] In this embodiment, both the first middle skin 103 and the second middle skin 104 are made of glass fiber cloth through natural curing with unsaturated polyester resin.

[0056] In this embodiment, the cured skin is sanded and roughened to clean the surface of the cured skin and roughen the surface to make the bonding between the structural layers tighter.

[0057] In this embodiment, according to the design scheme of the radome top plate, the core material of the top plate 1 is a three-dimensional fabric 102 sandwich fiberglass plate. Its theoretical single-pass transmission loss at 3GHz is 0.2dB, and the test values ​​are all less than 0.12dB, which meets the requirements of the antenna for the radome transmission loss. In addition, the air traffic control single secondary antenna rotates in the horizontal direction, and the transmission performance of the top plate has little impact on the antenna. The radome has been tested and calibrated, and the top plate of the radome has little impact on the transmission loss, thus verifying the feasibility of the design.

[0058] In this embodiment, finite element analysis software was used to perform stress analysis on the top plate with an area of ​​180×180mm2 and a load-bearing capacity of 1500kg. The maximum tensile stress of the skin was 35.479MPa, the maximum compressive stress was -37.879MPa, and the maximum stress of the three-dimensional fabric 102 was 0.105116MPa. All of these values ​​are less than the ultimate strength, meeting the load-bearing requirement of 1500kg and satisfying the safety risk prevention requirements for maintenance personnel in foreign countries.

[0059] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A high-load-bearing top plate for an antenna radome, characterized in that: It includes a top plate (1), which is a C-layer structure. The top plate (1) is formed by resin impregnation and curing. The top plate (1) includes a first inner skin (105), a second inner skin (106), a first middle skin (103), a second middle skin (104), an outer skin (101), an outer skin chopped strand mat, and an inner skin chopped strand mat. The outer skin chopped strand mat, outer skin (101), first middle skin (103), second middle skin (104), first inner skin (105), second inner skin (106), and inner skin chopped strand mat are arranged layer by layer from top to bottom. The outer skin (101) and the first middle skin (103) are separated from each other, and the second middle skin (104) and the first inner skin (105) are separated from each other. 5) Three-dimensional fabric (102) is sandwiched between each other. The three-dimensional fabric (102) includes multiple fiber layers arranged sequentially from top to bottom. Each pair of adjacent fiber layers is connected by multiple fiber cores. The fiber cores are shaped like an "8" in the radial direction and "1" in the weft direction. The three-dimensional fabric (102) is vacuum-assisted molded with thermosetting resin. During molding, a vacuum pump is used to vacuum the three-dimensional fabric (102) and resin is introduced at the same time. After the resin has filled the three-dimensional fabric (102) and the first middle skin (103) or the resin has filled the three-dimensional fabric (102) and the first inner skin (105), the vacuum pump is turned off, allowing the three-dimensional fabric (102) to expand naturally to the specified thickness and to cure naturally.

2. The high load-bearing top plate of the radome according to claim 1, characterized in that: The first inner skin (105) includes two layers of EWR400 fabric arranged sequentially from top to bottom, and the second inner skin (106) includes eight layers of EWR400 fabric and two layers of EWR200 fabric arranged sequentially from top to bottom.

3. The high load-bearing top plate of the radome according to claim 1, characterized in that: The first middle skin (103) comprises three layers of EWR400 fabric arranged sequentially from top to bottom, and the second middle skin (104) comprises two layers of EWR400 fabric arranged sequentially from top to bottom.

4. The high load-bearing top plate of the radome according to claim 1, characterized in that: The outer skin (101) comprises two layers of EWR200 fabric and eight layers of EWR400 fabric arranged sequentially from top to bottom.

5. The high load-bearing top plate of the radome according to claim 1, characterized in that: The top plate (1) is provided with a ventilation duct (2).

6. The high load-bearing top plate of the radome according to claim 5, characterized in that: The top of the top plate (1) is provided with multiple lifting rings (4), which are symmetrically arranged on both sides of the ventilation cylinder (2).

7. The high load-bearing top plate of the radome according to claim 5, characterized in that: A short ladder (3) is provided at the bottom of the top plate (1), and the top of the short ladder (3) is connected to the ventilation duct (2).

8. The high load-bearing top plate of the radome according to claim 1, characterized in that: Both the outer and inner chopped strand mats are covered with gel coats.

9. A method for forming a high load-bearing top plate of an antenna radome as described in claim 1, characterized in that: It includes the following steps: Step 1: Spray gel coat onto the surface of the female mold, and then heat the mold to accelerate the curing speed of the gel coat; Step 2: After the gel coat has cured, lay the outer skin chopped strand mat on the gel coat surface, then impregnate the first chopped strand mat with resin, and then lay the two layers of EWR200 fabric and eight layers of EWR400 fabric of the outer skin (101) in sequence according to the layering structure, and impregnate them with resin. Step 3: Lay the three-dimensional fabric (102) on the impregnated outer skin (101), and then lay the two layers of EWR400 fabric of the first middle skin (103) on the three-dimensional fabric (102) in sequence. Then use a vacuum pump to vacuum the three-dimensional fabric (102) and simultaneously introduce resin. After the resin has filled the three-dimensional fabric (102) and the first middle skin (103), turn off the vacuum pump and let the three-dimensional fabric (102) expand naturally to the specified thickness and then cure naturally. Step 4: After curing, use a flat mold to sand and roughen the first middle skin (103). After sanding and roughening, place the three layers of EWR400 fabric of the second middle skin (104) on the first middle skin (103) and impregnate it with resin. Then place the second layer of three-dimensional fabric (102) on the impregnated second middle skin (104). Then place the two layers of EWR400 fabric of the first inner skin (105) on the second layer of three-dimensional fabric (102). Then use a vacuum pump to vacuum the second layer of three-dimensional fabric (102) and simultaneously introduce resin. After the resin has filled the three-dimensional fabric (102) and the first inner skin (105), turn off the vacuum pump and let the three-dimensional fabric (102) expand naturally to the specified thickness and cure naturally. After curing, sand and roughen the first inner skin (105). Step 5: Spray gel coat onto the male mold, and then heat the mold to accelerate the curing speed of the gel coat; Step 6: Lay the inner lining chopped strand mat and the two layers of EWR200 fabric of the second inner lining (106) onto the positive mold in the order of the layup structure, and impregnate them with resin. At the same time, lay the eight layers of EWR400 fabric of the second inner lining (106) onto the product of the negative mold that has been sanded and roughened in the order of the layup structure, and impregnate it with resin. Step 7: Then, the male mold and female mold are joined together, and vacuum treatment is performed to shape it. After solidification, demolding and edge trimming are performed to complete the molding of the top plate (1). Step 8: After the top plate (1) is formed, complete the assembly of the top plate (1), the lifting ring (4), the short ladder (3) and the ventilation duct (2).

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