Preparation method of large-scale structure and function integrated composite material comprehensive mast

Abstract

The invention discloses a large-scale structure and function integrated composite material comprehensive mast in the technical field of composite material products, and the mast comprises a base which is made of a metal material and is used for fixing an outer wall in a use environment of the mast; the outer wall is made of composite materials and fixed to the top of the base, an equipment cavity used for containing equipment is formed in the outer wall, and a plurality of equipment cabin doors are formed in the surface; the floor is made of a composite material and is fixed in the outer wall, the space in the outer wall is divided into multiple layers, and the frequency-selecting and wave-transmitting functions are achieved at the same time, and the mechanical property can be borne at the same time; the problem of size change caused by inconsistent thermal expansion coefficients after the composite material and the metal material are installed is solved.

Description

Technical Field

[0001] The invention relates to the technical field of composite products, and in particular to a method for preparing a mast. Background Art

[0002] Masts were originally high poles used to hang sails and flags, install antennas, and support observation platforms. In the early days, masts were all made of wood. After the development of steel ships, steel masts were widely used. Today, masts are not only used on ships, but also on the tops of signal transmission towers, such as power signal transmission towers, radio and television signal transmission towers, mobile phone signal transmission towers, etc.

[0003] At present, masts have developed into multifunctional equipment with load bearing, antenna installation, various radars, etc. Therefore, the demand for masts to install multi-band radar equipment, wind and rain protection, and even frequency-selective wave transmission is becoming more and more obvious. At present, the metal masts used can bear loads, protect against wind and rain, but cannot achieve the overall frequency-selective wave transmission function. Therefore, it is necessary to select new materials and new processes to realize a comprehensive mast that can carry loads, protect against wind and rain, and achieve frequency-selective wave transmission and electromagnetic stealth. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a preparation method for a large-scale structural and functional integrated composite material integrated mast, which is constructed by composite materials to solve the current construction process of large-sized masts that only use metal materials; it is constructed by an autoclave integral molding process to ensure the integrity and structural strength of the mast, so that its structural mechanical properties are better; the functional material and the structural material are laid together, and the material is selected according to the radar band required to be transmitted or shielded, while satisfying the function of frequency-selective wave transmission and being able to bear mechanical properties; and the problem of dimensional change caused by the inconsistent thermal expansion coefficients of the composite material and the metal material after installation is solved.

[0005] The object of the present invention is achieved by: a method for preparing a large-scale structural and functional integrated composite material integrated mast, comprising the following steps: Step 1) The outer wall is formed by laying multiple layers of materials on a metal female mold. The outermost layer is a wave-transmitting material, which is quartz fiber reinforced cyanate prepreg. PMI foam, resistor film, PMI foam board, resistor film, PMI foam board, resistor film, and PMI foam board are laid in sequence. The above 8 layers constitute the wave-absorbing material. Finally, carbon fiber reinforced cyanate prepreg is laid, which can achieve electromagnetic shielding. Then a vacuum bag is made and put into an autoclave for high-temperature and high-pressure curing. After demoulding, the outer wall is obtained; Step 2) Floor molding, using a sandwich structure, including an upper skin, a middle layer, and a lower skin. The upper skin and the lower skin use the same carbon fiber reinforced cyanate prepreg as the outer wall, and the middle layer uses PMI foam. Then, a vacuum bag is made and put into an autoclave for high temperature and high pressure curing and molding. After demoulding, the floor is obtained; Step 3) The base is formed by first fixing the inner ring, bottom ring, reinforcing ribs and fixing plates to obtain a partial base; Step 4) Assemble the outer wall and the floor. Place the floor into the inner cavity of the outer wall, place the outer periphery of the floor close to the inner wall of the outer wall, and use the hand lay-up process to lay the same series of carbon fiber cloth and liquid cyanate ester resin to the connection between the outer wall and the floor. Lay them both up and down. After the hand lay-up is completed, wait for the resin to solidify at room temperature; Step 5) Assemble the outer wall and the base. First, put the bottom of the outer wall on the outer periphery of the inner ring and support it on the bottom ring. Finally, fix the outer ring and the bottom ring, and clamp the outer wall. Finally, use fasteners to fix the inner ring, outer wall, and outer ring to complete the assembly of the entire mast.

[0006] Furthermore, the large-scale structural and functional integrated composite material integrated mast includes: The base is made of metal material and is used to fix the outer wall to the use environment of the mast. The base adopts a frame structure, including an inner ring, a bottom ring and an outer ring. The inner ring and the outer ring are respectively fixed to the inner side and the outer side of the bottom ring. A groove for inserting the bottom of the outer wall is formed between the inner ring and the outer ring. Reinforcing ribs and fixing sheets are provided on the inner sides of the inner ring and the bottom ring. Corresponding waist-shaped holes are opened on the bottom of the outer wall and the base. Fasteners for fixing the outer wall and the base are provided in the waist-shaped holes. The outer wall is made of composite materials and fixed on the top of the base. An equipment cavity for accommodating equipment is formed inside the outer wall. A plurality of equipment doors are opened on the surface. The outer wall is made of carbon fiber prepreg, PMI foam, resistor film, quartz fiber prepreg and structural adhesive film. The floor is made of carbon fiber prepreg and PMI foam. The floor is made of composite material and fixed inside the outer wall to divide the space inside the outer wall into multiple layers. The connection between the floor and the outer wall is fixed by paving with carbon fiber cloth.

[0007] Furthermore, step 1) specifically includes: 1-1) After the metal female mold is ready, the quartz fiber reinforced cyanate prepreg and carbon fiber prepreg are cut into the required dimensions for the layer laying process by an automatic cutting machine; 1-2) First, lay the outermost layer of the outer wall material. The outermost layer is 0.6mm quartz fiber reinforced cyanate prepreg, and the thickness of the single layer of the material sheet is 0.2mm. A total of 3 layers need to be laid. After the laying is completed, a vacuum pre-evacuated bag is made to pre-compact the material sheet; 1-3) Laying a layer of cyanate structural adhesive film on the surface of the pre-compacted quartz fiber prepreg, and then laying a first layer of PMI foam board with a thickness of 2.5 mm to make vacuum pre-pouch pre-compacted sheet and foam board; 1-4) After the first layer of PMI foam board is laid, the cyanate ester structural adhesive film is laid on its surface, and then the first layer of resistor film is laid. The thickness of the first layer of electronic film is 0.1mm. After the laying is completed, the vacuum pre-pumping bag is continued to be pre-compacted into resistor film and foam board; 1-5) Continue to lay cyanate structural adhesive film on the surface of the first layer of resistor film, and then lay the second layer of PMI foam board. The thickness of the second layer of PMI foam board is 5mm. After the laying is completed, continue to make vacuum pre-evacuated bags to pre-compact the foam board and resistor film; 1-6) Lay a layer of ester structural adhesive film on the surface of the second layer of foam board, and then continue to lay the second layer of resistor film. The thickness of the second layer of resistor film is 0.1mm. After the laying is completed, make a vacuum pre-evacuated bag for pre-compaction; 1-7) Continue to lay a layer of cyanate structural adhesive film on the surface of the second layer of resistor film, and then lay the third layer of PMI foam board. The thickness of the third layer of PMI foam board is 5mm. After the laying is completed, make a vacuum pre-pumping bag for pre-compaction; 1-8) Lay a layer of cyanate structural adhesive film on the surface of the third layer of PMI foam board, and then lay the third layer of resistor film. The thickness of the resistor film is 0.1mm. After the laying is completed, make a vacuum pre-evacuated bag for pre-compaction; 1-9) Lay cyanate structural adhesive film on the surface of the third layer of resistor film, and then continue to lay the fourth layer of PMI foam with a thickness of 5mm. After the laying is completed, make a vacuum pre-pumping bag for pre-compaction; 1-10) After the fourth layer of PMI foam board is laid, continue to lay a layer of cyanate structural adhesive film on its surface, and then lay the final carbon fiber prepreg, the thickness of which is 2mm. The single layer thickness of carbon fiber reinforced cyanate plain prepreg is 0.2mm. A total of 10 layers need to be laid. According to the design requirements, the thickness of each laid material sheet cannot exceed 4 layers, and vacuum pre-pumping bags need to be made for pre-compaction; 1-11) After all the sheets are laid, the final vacuum bag is made and put into the autoclave for high temperature and high pressure curing. The curing system is 130℃, 0.6Mpa for 1 hour, and then the temperature is raised to 180℃, 0.6Mpa for 3 hours. The outer wall after curing is separated from the mold, and the excess area is cut with a cutting machine to obtain the net size of the outer wall finished product.

[0008] Furthermore, the resistor film and the PMI foam board are both treated with carbon black and graphene to meet the requirements of frequency-selective wave transmission in a specified frequency band.

[0009] Furthermore, step 2) specifically includes: 2-1) Use a flat mold for paving. The thickness of the upper and lower skins of the floor is 2mm, and the thickness of a single layer is 0.2mm. First, lay the lower skin, which is carbon fiber cyanate prepreg. After laying 4 layers of prepreg, make a vacuum pre-pumped bag and pre-compacted sheet; 2-2) After the lower skin is laid, a layer of cyanate structural adhesive film is laid on its surface, and then a 30mm ordinary PMI foam board is laid. A layer of structural adhesive film is continued to be laid on the surface of the foam board. After the adhesive film is laid, a vacuum pre-evacuated bag is made for pre-compaction; 2-3) Finally, the upper skin is laid. The upper skin is also made of 2mm carbon fiber cyanate prepreg. The ply design angle is consistent with the lower skin. It is also pre-compacted once every 4 layers of prepreg. All the material pieces are laid in a technical groove, and the final vacuum bag is made and put into the autoclave for high temperature and high pressure curing. Its curing system is consistent with the outer wall of the mast.

[0010] Furthermore, the metal material of the base is consistent with the material of the substrate in the use environment.

[0011] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention is the first to replace the large composite mast with a composite material, whose density is only 1 / 5 of that of steel, greatly reducing the mast's own weight and saving a large amount of load space on the hull for installing other equipment and items. It can also reduce the load-bearing capacity of the launch tower and reduce the construction cost of the mother platform to a certain extent.

[0012] (2) The mast manufactured by composite material paving and autoclave integral molding technology is easy to install, which reduces the time and risk of high-altitude operations and further improves the safety of operators.

[0013] (3) The successful development of a large composite material structure with integrated functions has solved the problem of easy detachment of the traditional spraying and pasting of the radar-absorbing and stealth functional layer materials on the outside of the metal structure layer, reducing maintenance costs and ensuring service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0015] Figure 1 It is a schematic diagram of the mast structure of the present invention.

[0016] Figure 2 It is a schematic diagram of the base structure of the mast in the present invention.

[0017] Figure 3 It is a cross-sectional view of the base of the mast of the present invention.

[0018] Figure 4 It is a schematic diagram of the internal structure of the mast in the present invention.

[0019] Figure 5 It is a schematic diagram of the floor structure of the mast in the present invention.

[0020] Figure 6 It is a schematic diagram of the connection between the outer wall of the mast and the floor in the present invention.

[0021] Figure 7 It is a schematic diagram of the outer wall ply of the mast in the present invention.

[0022] Among them, 100 is the base, 101 is the inner ring, 102 is the bottom ring, 103 is the outer ring, 104 is the reinforcing rib, 105 is the fixing plate, 200 is the outer wall, 201 is the equipment door, 300 is the floor, 301 is the upper skin, 302 is the middle layer, and 303 is the lower skin. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1 like Figure 1-7 A large-scale composite mast with integrated structure and function is shown, comprising: The base 100 is made of metal material and is used to fix the outer wall 200 to the use environment of the mast; The outer wall 200 is made of composite material, and consists of four side surfaces and a top surface, and is fixed to the top of the base 100. The inner part thereof forms an equipment cavity for accommodating equipment, and a plurality of equipment doors 201 are opened on the surface; The floor 300 is made of composite material and is fixed inside the outer wall 200 to divide the space inside the outer wall 200 into multiple layers.

[0025] Furthermore, the base 100 adopts a frame structure, including an inner ring 101, a bottom ring 102 and an outer ring 103. The inner ring 101 and the outer ring 103 are respectively fixed on the inner and outer sides of the bottom ring 102. A groove for inserting the bottom of the outer wall 200 is formed between the inner ring 101 and the outer ring 103. Reinforcing ribs 104 and fixing plates 105 are provided on the inner sides of the inner ring 101 and the bottom ring 102. Corresponding waist-shaped holes are opened on the bottom of the outer wall 200 and the base 100, and fasteners for fixing the outer wall 200 and the base 100 are provided in the waist-shaped holes.

[0026] It should be noted that the inner ring 101, the bottom ring 102, and the outer ring 103 are of a square structure as a whole, and together form a square frame. Such a design facilitates the formation of a groove for inserting the outer wall 200; the design of the reinforcing ribs 104 enhances the structural strength of the frame; the design of the fixing plate 105 facilitates the welding of the base 100 with the deck or the launch tower.

[0027] Furthermore, the outer wall 200 is made of carbon fiber prepreg, PMI foam, resistor film, quartz fiber prepreg and structural adhesive film, and the floor 300 is made of carbon fiber prepreg and PMI foam, including an upper skin 301, an intermediate layer 302, and a lower skin 303. The upper skin 301 and the lower skin 303 use the same carbon fiber reinforced cyanate prepreg as the outer wall 200, and the intermediate layer 302 uses PMI foam.

[0028] Furthermore, the connection between the floor 300 and the outer wall 200 is fixed by paving with carbon fiber cloth.

[0029] The main structure of the mast in this embodiment is 8.5m high, with a bottom size of 7.8m×5.3m and a top size of 5.75m×3.2m. The space structure is divided into three layers, each of which is separated by a floor 300. Each layer of the mast has four equipment doors 201, which are used to install radar and other signal transmitting devices in the later stage. A metal base 100 is installed at the bottom of the mast, and the metal base 100 can be welded to the metal ship deck and the launch tower.

[0030] Specifically, except for the bottom connecting metal adapter plate of the mast which is made of the same material as the parent material to be welded, the rest of the materials are all made of composite materials.

[0031] Specifically, the composite material parts of the mast mainly include the mast outer wall 200 and the floor 300. Since the floor 300 does not involve the requirements of frequency selection and wave transmission, it is only made of ordinary carbon fiber composite materials.

[0032] Specifically, the electromagnetic shielding performance of the mast outer wall 200 frequency-selective wave transmission and stealth requirements is: the average isolation degree in the 3MHz-29MHz frequency band is less than 20dB; the isolation degree in the 30MHz-3GHz frequency band is less than 25dB; the average isolation degree in the 5GHz-18GHz frequency band is not less than 40dB.

[0033] Specifically, the frequency-selective wave transmission and stealth requirements of the outer wall 200 of the mast have wave absorption performance: the outer wall 200 has vertical incidence of 2GHz-8GHz≤-10dB, 8GHz-18GHz≤-15dB; 45° oblique incidence of 2GHz-8GHz≤-8dB, 8GHz-18GHz≤-12dB.

[0034] The following is a list of the materials that make up the main parts of the mast: Serial number Parts Name Material composition Remark 1 Mast outer wall Carbon fiber prepreg + PMI foam + resistor film + quartz fiber prepreg + structural adhesive film With electromagnetic shielding and frequency-selective wave transmission functions + load-bearing structure strength function 2 One floor Carbon fiber prepreg + PMI foam Load-bearing structure strength function 3 Second floor Carbon fiber prepreg + PMI foam Load-bearing structure strength function 4 Bottom metal connection adapter plate Select the same grade of metal material according to the parent material (hull deck material, launch tower material, etc.) Bearing structure strength function + connection function Example 2 A method for preparing a large-scale structural and functional integrated composite material integrated mast comprises the following steps: Step 1) Mast outer wall 200 molding The mast outer wall 200 is formed by paving a metal female mold, which is made of ordinary Q235 steel welding and processing. In order to ensure the external dimensions of the outer wall 200, the steel mold design needs to reduce the actual size of the mold at room temperature according to the expansion coefficient of the mast outer wall 200 at high temperature during the curing process; due to the large size of the mold, a splicing combination method is adopted to achieve the size and precision processing of the inner surface of the female mold; the mast outer wall 200 involves two prepregs, a resistor film, two specifications of PMI foam boards, and cyanate structural adhesive film is used between each material for simultaneous paving to increase the interlayer strength.

[0035] 1-1) After the mold is ready, the quartz fiber prepreg and carbon fiber prepreg are cut into the required dimensions for the layer laying process using an automatic cutting machine; 1-2) First, lay the outermost layer of the mast outer wall 200, which is 0.6mm quartz fiber reinforced cyanate ester plain prepreg, with a single layer thickness of 0.2mm. A total of 3 layers need to be laid. According to the design, the laying angle is (0°, 90°, 0°), where the mast height direction is 0°. After the laying is completed, a vacuum pre-evacuated bag is made to pre-compact the sheet; 1-3) A layer of cyanate structural adhesive film is laid on the surface of the pre-compacted quartz fiber prepreg to increase the bonding performance between the prepreg and other material layers, and then a 2.5mm thick PMI foam board is laid. In order to ensure that the foam board and the adhesive film as well as the prepreg are laid tightly, a vacuum pre-pumped bag pre-compacted sheet and foam board are made; 1-4) After the first layer of foam board is laid, the cyanate structural adhesive film is laid on its surface, and then the first layer of resistor film is laid. The thickness of the electronic film is 0.1mm. After the laying is completed, continue to make vacuum pre-pumped bags to pre-compact the resistor film and foam board; 1-5) Continue to lay cyanate structural adhesive film on the surface of the first layer of resistor film, and then lay the second layer of PMI foam board. The thickness of the second layer of foam board is 5mm. After the laying is completed, continue to make vacuum pre-evacuated bags to pre-compact the foam board and resistor film; 1-6) Lay a layer of ester structural adhesive film on the surface of the second layer of foam board, and then continue to lay the second layer of resistor film. The thickness of the second layer of resistor film is still 0.1mm. After the laying is completed, make a vacuum pre-evacuated bag for pre-compaction; 1-7) Continue to lay a layer of cyanate structural adhesive film on the surface of the second layer of resistor film, and then lay the third layer of PMI foam board. The thickness of the third layer of foam board is 5mm. After the laying is completed, make a vacuum pre-pumping bag for pre-compaction; 1-8) Lay a layer of cyanate structural adhesive film on the surface of the third layer of PMI foam board, and then lay the third layer of resistor film. The thickness of the resistor film is still 0.1mm, which is the last layer of resistor film. After the laying is completed, make a vacuum pre-pumping bag for pre-compaction; 1-9) Lay cyanate structural adhesive film on the surface of the third layer of resistor film, and then continue to lay the fourth layer of PMI foam, which is also the last layer of foam board, with a thickness of 5mm. After the laying is completed, make a vacuum pre-pumping bag for pre-compaction; 1-10) After the last layer of foam board is laid, continue to lay a layer of cyanate structural adhesive film on its surface, and then lay the last carbon fiber prepreg, the thickness of which is 2mm, and the single layer thickness of carbon fiber reinforced cyanate plain prepreg is 0.2mm. A total of 10 layers need to be laid. According to the design requirements, the thickness of each laid sheet cannot exceed 4 layers. Vacuum pre-pumping bags must be made and pre-compacted to ensure that there are no bubbles, pores, wrinkles, etc. between the sheets. In this way, the process of laying carbon fiber prepreg steamer needs to be pre-compacted 3 times, and the layer design angle is (0°, 45°, 90°, -45°, 0°, 0°, -45°, 90°, 45°, 0°); 1-11) After all the sheets are laid, the final vacuum bag is made and put into the autoclave for high temperature and high pressure curing. The curing system is 130℃, 0.6Mpa for 1 hour, and then the temperature is raised to 180℃, 0.6Mpa for 3 hours. After curing, the mast outer wall 200 is separated from the mold, and the excess area is cut with a cutting machine to obtain the net size of the mast outer wall 200 finished product.

[0036] Step 2) Floor 300 molding manufacturing The mast floor 300 mainly includes a first floor 300 and a second floor 300, wherein the first floor 300 has a size of 5.67m×3.67m, and the second floor 300 has a size of 5.34m×3.23m. The thickness of the two floors 300 is 34mm, which is an upper and lower skin 303 plus a foam sandwich structure.

[0037] The floor 300 is a flat plate structure, which can be laid with a steel flat plate mold. According to the size of the two layers of floor 300, a corresponding size cutting drawing is made, and the material pieces are cut using an automatic cutting machine. The thickness of the upper and lower skins 303 of the floor 300 is 2mm. First, the lower skin 303 is laid. The design angle of the lower skin 303 is (0°, 45°, 90°, -45°, 0°, 0°, -45°, 90°, 45°, 0°). Similarly, vacuum pre-pouch pre-compacted material pieces are made according to the laying of 4 layers of prepreg.

[0038] After the 303 lower skin is laid, a layer of cyanate structural adhesive film is laid on its surface, and then a 30mm ordinary PMI foam board is laid. A layer of structural adhesive film is continued to be laid on the surface of the foam board. After the film is laid, a vacuum pre-vacuum bag is made for pre-compaction.

[0039] Finally, the upper skin 301 is laid. The upper skin 301 is also made of 2mm carbon fiber cyanate prepreg. Its ply design angle is consistent with the lower skin 303. It is also pre-compacted once every 4 layers of prepreg. All the sheets are laid in a technical groove, and the final vacuum bag is made and put into the autoclave for high temperature and high pressure curing. Its curing system is consistent with the mast outer wall 200.

[0040] Step 3) Bottom metal connection adapter board The bottom metal connecting adapter plate is mainly used to connect the composite mast to the mother platform. Its material is consistent with the mother platform, which can ensure welding with the mother platform. The outer wall 200 of the mast is made of composite materials. In order to solve the different thermal expansion coefficients between it and the metal adapter plate, waist-shaped holes are used to connect to achieve small position slippage.

[0041] The metal transfer plate is mainly made of metal plates and profiles through laser cutting and then welding. Finally, it can be fine-machined to size and punch waist-shaped holes through the gantry CNC machining center according to the installation accuracy.

[0042] Step 4) Hand-bonding The floor 300 and the mast outer wall 200 are both composite materials. To make them more integrated, the floor 300 and the mast outer wall 200 are connected by hand lay-up. According to the design, the same series of carbon fiber cloth and liquid cyanate resin as the mast are used. The hand lay-up thickness is 2mm above the ground and 2mm below the floor 300. The single-side width of the hand lay-up connection is 150mm. Since the thickness of a single hand lay-up layer is 0.25mm, the number of hand lay-up sheets is 8. After the hand lay-up is completed, wait at room temperature for more than 8 hours to ensure the resin is cured.

[0043] In this embodiment, according to the design, the outer wall 2005 of the mast adopts a fully composite integrated construction process, and foam core material, frequency-selective wave transmission, electromagnetic shielding, and load-bearing structure prepreg are mixed and laid, and then put into an autoclave for one-time high-temperature and high-pressure curing. The first floor 300 and the second floor 300 are mixed and laid with load-bearing structure prepreg and foam core material, and then put into an autoclave for high-temperature and high-pressure curing. The bottom connection adapter plate is welded with metal materials.

[0044] The main dimensions of the mast wall panel are a pentahedral tower structure with a height of 8.5 m, a bottom dimension of 7.8 m × 5.3 m, and a top dimension of 5.75 m × 3.2 m. According to the design requirements, in order to make its structural strength better integrated, the 5 faces are paved as a whole, and in order to ensure the smoothness of the mast shape, metal negative molds are used for paving.

[0045] The outermost layer of the mast outer wall 200 is a wave-transmitting material, which is paved with 0.6mm quartz fiber reinforced cyanate prepreg (single layer thickness 0.2mm, 3 layers), followed by 2.5mm thick PMI foam, 0.1mm thick resistor film, 5mm thick PMI foam board, 0.1mm thick resistor film, 5mm thick PMI foam board, 0.1mm thick resistor film, and 5mm rear PMI foam board. The above 8 layers constitute the wave-absorbing material, and finally 2mm carbon fiber reinforced cyanate prepreg (single layer thickness 0.2mm, 10 layers) can also achieve electromagnetic shielding. The 9 layers of materials are combined into the mast outer wall 200 material that can achieve frequency-selective wave transmission and load-bearing structural strength. Among them, the resistor film and PMI foam board are both treated with carbon black and graphene, which are unconventional materials. Therefore, the requirements of frequency-selective wave transmission in the specified frequency band can be met through material selection and design of layer laying.

[0046] The specific processing process is as follows: a) Preparation of impregnation solution: Select appropriate carbon black and graphene materials as required, and disperse them in an appropriate solvent to prepare an impregnation solution. Use ultrasonic treatment or mechanical stirring to promote the dispersion of carbon black and graphene. Other additives such as surfactants, adhesives, etc. can be added to the impregnation solution as required to improve the dispersibility and adhesion of carbon black and graphene in the foam.

[0047] b) Foam impregnation: Soak the resistor film and PMI foam board in the impregnation liquid, and ensure that the foam fully absorbs the impregnation liquid. The impregnation effect can be controlled by adjusting the immersion time, temperature and concentration of the impregnation liquid. Vacuum impregnation or pressure impregnation can be used to improve the impregnation effect.

[0048] c) Drying: Take out the impregnated resistor film and PMI foam board from the impregnation liquid, and use filter paper or other absorbent materials to absorb the excess impregnation liquid on the surface. Place the foam in a well-ventilated environment and dry it naturally or in a low-temperature oven. The drying temperature and time should be adjusted according to the characteristics of the foam material and the composition of the impregnation liquid to avoid deformation or damage to the foam material.

[0049] It should be noted that a multi-layer structure is used as the outer plate material (outer quartz glass fiber layer, inner carbon fiber layer, middle foam + resistor film layer), the quartz fiber layer is wave-transmitting, the foam + resistor film layer absorbs waves, and the carbon fiber layer shields. From a functional point of view, after the electromagnetic wave passes through the quartz fiber layer, it absorbs the required frequency band waves multiple times (4 layers of absorbing foam, 4 layers of resistor film), and finally is reflected by the carbon fiber layer and continues to be absorbed. This back and forth absorption ensures that the electromagnetic waves of a specific band can be completely shielded. In terms of structural strength, the quartz fiber layer plays a role in structural strength, the foam + resistor film layer plays a role in internal filling to increase the structural modulus, and the carbon fiber layer plays a role in structural strength. The combined outer plate can meet the structural strength and rigidity of the entire mast. The summary shows that the raw materials and layer design used in the mast are complementary designs of function and structure, and it requires multiple simulation calculations to obtain the final layer design.

[0050] In this embodiment, the floor 300 is designed with two layers. The first floor 300 and the second floor 300 are both load-bearing structural parts, which do not need frequency-selective wave transmission and stealth functions. In order to ensure that the same material system is used as the outer wall 200, the upper and lower skins 303 use the same carbon fiber reinforced cyanate prepreg (single layer thickness 0.2mm, 10 layers), and the middle interlayer 302 uses a 30mm thick PMI conventional foam board (not treated with carbon black and graphene).

[0051] Since the floor 300 is a flat plate structure, it can be paved with an ordinary steel flat plate mold. After paving, a vacuum bag is made and put into an autoclave for high temperature and high pressure co-curing.

[0052] In this embodiment, the purpose of arranging a metal adapter plate at the bottom of the bottom mast is to connect with the hull, launch tower and other platforms. Since most ships and launch towers are made of steel materials, and the masts are made of composite materials, the two materials cannot be directly welded, so the metal material and the composite material are made of metal materials to make the adapter plate and welded to the hull or launch tower, and the adapter plate and the composite mast are connected by metal bolts.

[0053] Due to the large difference in thermal expansion coefficients between metal materials and organic composite materials, in different environments (large temperature differences between the equator and the North and South Poles), if metal and composite materials are directly connected using ordinary holes, the composite materials are easily cracked under multiple thermal expansion and contraction conditions, resulting in damage to the connection between the mast and the mother body. To solve this problem, the size changes of the mast and the bottom connection adapter plate are calculated based on the temperature difference in different environments, and waist-shaped holes of special lengths are designed and made. The composite mast and the adapter plate are both provided with waist-shaped holes of corresponding sizes. In this way, after the bolt connection is affected by thermal expansion and contraction, the composite material and the metal material can slide in the corresponding position, thereby avoiding pulling damage between the composite material and the metal material.

[0054] In this embodiment, the floor 300 and the outer wall 200 are both constructed of organic composite materials. The two have the same properties and the same thermal expansion coefficient. In order to ensure the integrity of the structural strength of the mast, carbon fiber cloth is hand-laid with liquid cyanate resin (room temperature curing resin) to connect them to ensure the consistency of the materials. Similarly, the strength of the hand-laid connection is more integrated.

[0055] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a large-scale composite mast with integrated structure and function, characterized in that: The following steps are involved: Step 1) The outer wall is formed by laying multiple layers of materials on a metal female mold. The outermost layer is a wave-transmitting material, which is quartz fiber reinforced cyanate prepreg. PMI foam, resistor film, PMI foam board, resistor film, PMI foam board, resistor film, and PMI foam board are laid in sequence. The above 8 layers constitute the wave-absorbing material. Finally, carbon fiber reinforced cyanate prepreg is laid, which can achieve electromagnetic shielding. Then a vacuum bag is made and put into an autoclave for high-temperature and high-pressure curing. After demoulding, the outer wall is obtained; Step 2) Floor molding, using a sandwich structure, including an upper skin, a middle layer, and a lower skin. The upper skin and the lower skin use the same carbon fiber reinforced cyanate prepreg as the outer wall, and the middle layer uses PMI foam. Then, a vacuum bag is made and put into an autoclave for high temperature and high pressure curing and molding. After demoulding, the floor is obtained; Step 3) The base is formed by first fixing the inner ring, bottom ring, reinforcing ribs and fixing plates to obtain a partial base; Step 4) Assemble the outer wall and the floor. Place the floor into the inner cavity of the outer wall, place the outer periphery of the floor close to the inner wall of the outer wall, and use the hand lay-up process to lay the same series of carbon fiber cloth and liquid cyanate ester resin to the connection between the outer wall and the floor. Lay them both up and down. After the hand lay-up is completed, wait for the resin to solidify at room temperature; Step 5) Assemble the outer wall and the base. First, put the bottom of the outer wall on the outer periphery of the inner ring and support it on the bottom ring. Finally, fix the outer ring and the bottom ring, and clamp the outer wall. Finally, use fasteners to fix the inner ring, outer wall, and outer ring to complete the assembly of the entire mast.

2. The method for preparing a large-scale structural and functional integrated composite material integrated mast according to claim 1, characterized in that: Large-scale composite mast with integrated structure and function includes: The base is made of metal material and is used to fix the outer wall to the use environment of the mast. The base adopts a frame structure, including an inner ring, a bottom ring and an outer ring. The inner ring and the outer ring are respectively fixed to the inner side and the outer side of the bottom ring. A groove for inserting the bottom of the outer wall is formed between the inner ring and the outer ring. Reinforcing ribs and fixing sheets are provided on the inner sides of the inner ring and the bottom ring. Corresponding waist-shaped holes are opened on the bottom of the outer wall and the base. Fasteners for fixing the outer wall and the base are provided in the waist-shaped holes. The outer wall is made of composite materials and fixed on the top of the base. An equipment cavity for accommodating equipment is formed inside the outer wall. A plurality of equipment doors are opened on the surface. The outer wall is made of carbon fiber prepreg, PMI foam, resistor film, quartz fiber prepreg and structural adhesive film. The floor is made of carbon fiber prepreg and PMI foam. The floor is made of composite material and fixed inside the outer wall to divide the space inside the outer wall into multiple layers. The connection between the floor and the outer wall is fixed by paving with carbon fiber cloth.

3. The method for preparing a large-scale composite mast with integrated structure and function according to claim 1 or 2, characterized in that: Step 1) specifically includes: 1-1) After the metal female mold is ready, the quartz fiber reinforced cyanate prepreg and carbon fiber prepreg are cut into the required dimensions for the layer laying process by an automatic cutting machine; 1-2) First, lay the outermost layer of the outer wall material. The outermost layer is 0.6mm quartz fiber reinforced cyanate prepreg, and the thickness of the single layer of the material sheet is 0.2mm. A total of 3 layers need to be laid. After the laying is completed, a vacuum pre-evacuated bag is made to pre-compact the material sheet; 1-3) Laying a layer of cyanate structural adhesive film on the surface of the pre-compacted quartz fiber prepreg, and then laying a first layer of PMI foam board with a thickness of 2.5 mm to make vacuum pre-pouch pre-compacted sheet and foam board; 1-4) After the first layer of PMI foam board is laid, the cyanate ester structural adhesive film is laid on its surface, and then the first layer of resistor film is laid. The thickness of the first layer of electronic film is 0.1mm. After the laying is completed, the vacuum pre-pumping bag is continued to be pre-compacted into resistor film and foam board; 1-5) Continue to lay cyanate structural adhesive film on the surface of the first layer of resistor film, and then lay the second layer of PMI foam board. The thickness of the second layer of PMI foam board is 5mm. After the laying is completed, continue to make vacuum pre-evacuated bags to pre-compact the foam board and resistor film; 1-6) Lay a layer of ester structural adhesive film on the surface of the second layer of foam board, and then continue to lay the second layer of resistor film. The thickness of the second layer of resistor film is 0.1mm. After the laying is completed, make a vacuum pre-evacuated bag for pre-compaction; 1-7) Continue to lay a layer of cyanate structural adhesive film on the surface of the second layer of resistor film, and then lay the third layer of PMI foam board. The thickness of the third layer of PMI foam board is 5mm. After the laying is completed, make a vacuum pre-pumping bag for pre-compaction; 1-8) Lay a layer of cyanate structural adhesive film on the surface of the third layer of PMI foam board, and then lay the third layer of resistor film. The thickness of the resistor film is 0.1mm. After the laying is completed, make a vacuum pre-evacuated bag for pre-compaction; 1-9) Lay cyanate structural adhesive film on the surface of the third layer of resistor film, and then continue to lay the fourth layer of PMI foam with a thickness of 5mm. After the laying is completed, make a vacuum pre-pumping bag for pre-compaction; 1-10) After the fourth layer of PMI foam board is laid, continue to lay a layer of cyanate structural adhesive film on its surface, and then lay the final carbon fiber prepreg, the thickness of which is 2mm. The single layer thickness of carbon fiber reinforced cyanate plain prepreg is 0.2mm. A total of 10 layers need to be laid. According to the design requirements, the thickness of each laid material sheet cannot exceed 4 layers, and vacuum pre-pumping bags need to be made for pre-compaction; 1-11) After all the sheets are laid, the final vacuum bag is made and put into the autoclave for high temperature and high pressure curing. The curing system is 130℃, 0.6Mpa for 1 hour, and then the temperature is raised to 180℃, 0.6Mpa for 3 hours. The outer wall after curing is separated from the mold, and the excess area is cut with a cutting machine to obtain the net size of the outer wall finished product.

4. The method for preparing a large-scale structural and functional integrated composite material integrated mast according to claim 1 or 2, characterized in that: The resistor film and the PMI foam board are both treated with carbon black and graphene to meet the requirements of frequency-selective wave transmission in a specified frequency band.

5. The method for preparing a large-scale composite mast with integrated structure and function according to claim 1 or 2, characterized in that: Step 2) specifically includes: 2-1) Use a flat mold for paving. The thickness of the upper and lower skins of the floor is 2mm, and the thickness of a single layer is 0.2mm. First, lay the lower skin, which is carbon fiber cyanate prepreg. After laying 4 layers of prepreg, make a vacuum pre-pumped bag and pre-compacted sheet; 2-2) After the lower skin is laid, a layer of cyanate structural adhesive film is laid on its surface, and then a 30mm ordinary PMI foam board is laid. A layer of structural adhesive film is continued to be laid on the surface of the foam board. After the adhesive film is laid, a vacuum pre-evacuated bag is made for pre-compaction; 2-3) Finally, the upper skin is laid. The upper skin is also made of 2mm carbon fiber cyanate prepreg. The ply design angle is consistent with the lower skin. It is also pre-compacted once every 4 layers of prepreg. All the material pieces are laid in a technical groove, and the final vacuum bag is made and put into the autoclave for high temperature and high pressure curing. Its curing system is consistent with the outer wall of the mast.

6. The method for preparing a large-scale composite mast with integrated structure and function according to claim 1 or 2, characterized in that: The metal material of the base is consistent with the material of the substrate in the use environment.

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