High-performance lightweight composite board and structure

Abstract

The invention relates to the technical field of composite materials, in particular to a high-performance lightweight composite board and a structure. The embodiment of the invention provides a high-performance light-weight composite board. The high-performance light-weight composite board sequentially comprises a lower reinforcing layer and an upper reinforcing layer in the thickness direction. The upper reinforcing layer and the lower reinforcing layer are made of fiber reinforced resin matrix composite materials, the space between the upper reinforcing layer and the lower reinforcing layer is filled with fabric composite materials, and the fabric composite materials are formed by compounding hollow fabric and continuous metal wires through epoxy resin. The embodiment of the invention provides a high-performance light-weight composite board and a structure. The composite board which is light in weight, high in appearance flatness, low in preparation cost and high in overall structural rigidity and strength can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to a high-performance lightweight composite board and a structure. Background Art

[0002] At present, the boards used for buildings, large carriages or shelters, etc. mainly adopt steel and composite boards. The steel mainly has a flat structure, a corrugated metal plate structure and an aluminum honeycomb plate structure. The flat structure is mainly a flat plate made of steel or aluminum alloy; the corrugated metal plate is a flat plate made of steel or aluminum alloy formed by rolling or stamping, and has higher stiffness than the flat plate at the same thickness; the aluminum honeycomb plate structure is formed by bonding or welding an aluminum honeycomb core material and upper and lower alloy panels, and has a higher degree of strength quantification compared with the flat plate and corrugated structures. The composite board structures mainly include high-performance fiber laminates such as glass / carbon and lightweight sandwich structure boards. The glass fiber laminate has limited stiffness. Although the carbon fiber laminate has high strength and high modulus, its cost is relatively high and it cannot be applied to all occasions; the sandwich structure board is formed by bonding a foam / honeycomb core material and upper and lower fiber laminates with an adhesive film, and has a high degree of lightweight, but its own structural strength is relatively low.

[0003] In view of the above problems, there is an urgent need for a composite board with light weight, high appearance flatness, low preparation cost and high overall structural stiffness and strength. Summary of the Invention

[0004] The embodiments of the present invention provide a high-performance lightweight composite board and a structure, and a composite board with light weight, high appearance flatness, low preparation cost and high overall structural stiffness and strength can be obtained.

[0005] In a first aspect, the embodiments of the present invention provide a high-performance lightweight composite board, which sequentially includes a lower reinforcing layer and an upper reinforcing layer along the thickness direction;

[0006] The preparation materials of the upper reinforcing layer and the lower reinforcing layer both include fiber-reinforced resin matrix composites, and a fabric composite material is filled between the upper reinforcing layer and the lower reinforcing layer. The fabric composite material is formed by compounding a hollow fabric and continuous metal wires through epoxy resin.

[0007] In a possible design, the reinforcing body of the fiber-reinforced resin matrix composite includes one or more combinations of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber, and the matrix of the fiber-reinforced resin matrix composite includes epoxy resin.

[0008] In a possible design, the hollow fabric is woven by one or more combinations of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber.

[0009] In a possible design, a metal mesh is provided between layers and / or on the surface of the upper reinforcing layer or the lower reinforcing layer.

[0010] In a possible design, the preparation material of the metal mesh includes T2 copper wire mesh and / or stainless steel wire mesh.

[0011] In a possible design, the composite sheet is integrally formed by a vacuum infusion molding process.

[0012] In a second aspect, an embodiment of the present invention provides a structure, including a first composite sheet and a second composite sheet. The first composite sheet is any one of the above composite sheets. The first composite sheet is rotatably connected to a fixing part. The second composite sheet is rotatably connected to the first composite sheet. The first composite sheet is a flat sheet. The second composite sheet is a sheet with an L-shaped cross-section and includes the fabric composite material. The first composite sheet and the fixing part are connected by a folding rod. The folding rod includes a first rod body and a second rod body that are rotatably connected. The first rod body and the second rod body are respectively rotatably connected to the first composite sheet and the fixing part. Power devices are connected to both ends of the rotational connection of the first rod body and the second rod body. The power device is used to provide power to change the rotation angle at the rotational connection. The first composite sheet and the second composite sheet are connected by a telescopic rod with a hydraulic or pneumatic system;

[0013] The first composite sheet and the second composite sheet are driven by driving the telescopic rod and the folding rod.

[0014] In a possible design, a C-shaped frame is provided around the first composite sheet. The four sides of the first composite sheet are inserted into the grooves of the C-shaped frame. The four C-shaped frames are fixed by screwing. The density of the pile warp of the hollow fabric near the C-shaped frame is higher than that at other positions.

[0015] In a possible design, a hollow support rod is inserted into the fabric composite material of the first composite sheet. The cross-section of the support rod is rectangular. The cross-section height of the support rod is the same as the thickness of the fabric composite material, so that it is supported between the upper reinforcing layer and the lower reinforcing layer. At the position where the hollow fabric is used to set the support rod, it is only interwoven with the warp and weft yarns at the surface layer to reserve a space for inserting the support rod.

[0016] In a possible design, a strip-shaped frame for supporting the upper reinforcing layer and the lower reinforcing layer is provided around the second composite sheet. The outside of the second composite sheet is wrapped with an outer skin.

[0017] The present invention has at least the following beneficial effects compared with the prior art:

[0018] In this embodiment, the fabric composite material has a hollow structure, which can not only provide high strength but also lightweight properties. The surface of the entire plate body is highly flat and relatively beautiful. The composite plate is mainly composed of fiber resin composite materials, taking into account strength, stiffness, and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of a first composite plate provided by an embodiment of the present invention;

[0021] Figure 2 It is a schematic structural diagram of a second composite plate provided by an embodiment of the present invention;

[0022] Figure 3a It is a schematic structural diagram of the opening and closing state of a structure provided by an embodiment of the present invention;

[0023] Figure 3b It is a schematic structural diagram of the closed state of a structure provided by an embodiment of the present invention.

[0024] In the figure:

[0025] 1 - Lower strengthening layer;

[0026] 2 - Upper strengthening layer;

[0027] 3 - Hollow fabric;

[0028] 4 - Metal mesh;

[0029] 5 - C-shaped frame;

[0030] 6 - Support rod;

[0031] 7 - Strip-shaped frame;

[0032] 8 - Outer skin;

[0033] 9 - Hinge;

[0034] 100 - First composite plate;

[0035] 200 - Second composite plate;

[0036] 300 - Fixed part;

[0037] 400 - Folding rod;

[0038] 500 - telescopic rod. Detailed implementation mode

[0039] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] In the description of the embodiments of the present invention, unless otherwise clearly defined and limited, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; unless otherwise specified or stated, the term "plural" means two or more; the terms "connection", "fixation", etc. should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the description of this specification, it should be understood that the orientation terms such as "upper" and "lower" described in the embodiments of the present invention are described from the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that one element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element.

[0042] As Figure 1 shown, the embodiments of the present invention provide a high-performance lightweight composite board, which sequentially includes a lower strengthening layer 1 and an upper strengthening layer 2 along the thickness direction;

[0043] The preparation materials of the upper strengthening layer 2 and the lower strengthening layer 1 both include fiber-reinforced resin matrix composites, and a fabric composite material is filled between the upper strengthening layer 2 and the lower strengthening layer 1. The fabric composite material is formed by compounding a hollow fabric 3 and continuous metal wires through epoxy resin.

[0044] In this embodiment, the fabric composite material has a hollow structure, which can not only provide high strength but also provide lightweight properties. The surface flatness of the entire board is high and it is relatively beautiful. The composite board is mainly composed of fiber resin composite materials, taking into account strength, stiffness and cost.

[0045] In this embodiment, after the composite board is completed, the surface of the composite material board is subjected to surface treatment and coating of fluorocarbon, shielding, stealth, camouflage and other coatings, which not only beautifies the appearance of the board, but also improves its environmental adaptability such as corrosion resistance and moisture resistance, as well as special camouflage protection functions such as infrared stealth / electromagnetic shielding.

[0046] If necessary, if the composite material board has low requirements for temperature adaptability, phenolic resin can be used for the composite resin of the upper reinforcing layer 2, the hollow fabric 3 and the lower reinforcing layer 1; if the composite material board has high temperature resistance requirements, polyimide resin or silicon-containing arylene resin can be used for the composite resin of the upper reinforcing layer 2, the hollow fabric 3 and the lower reinforcing layer 1 according to temperature needs.

[0047] In some embodiments of the present invention, the reinforcement of the fiber-reinforced resin matrix composite includes one or more combinations of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber, and the matrix of the fiber-reinforced resin matrix composite includes epoxy resin.

[0048] In some embodiments of the present invention, the hollow fabric 3 is woven from one or more combinations of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber.

[0049] Based on the conventional organizational structure of the hollow fabric 3, at the position of the composite board support rod 6, the organizational structure in which the pile warp penetrates and interweaves through the upper and lower layers is changed, and it only interweaves with the warp and weft yarns at the surface layer. At the same time, the distribution density of the pile warp is increased at the fabric frame assembly to ensure the structural stability of the assembly. Based on the conventional organizational structure of the hollow fabric 3, at the position of the support rod 6, the organizational structure in which the pile warp penetrates and interweaves through the upper and lower layers is changed, and it only interweaves with the warp and weft yarns at the surface layer. At the same time, the distribution density of the pile warp is increased at the fabric frame assembly to ensure the structural stability of the assembly.

[0050] The hollow fabric 3 is a continuous cavity structure formed by integrally weaving high-performance fibers, and is composed of upper and lower surface layers and Z-direction continuous fibers that connect and penetrate therebetween. There is no surface-core interface, and the natural sandwich structure provides excellent sound insulation and heat insulation performance. Its composite material has unique advantages such as strong anti-delamination and peeling, high wave transmission of the structure, and designability of shape / property. The composite material of the hollow fabric 3 can effectively reduce the weight of the traditional metal material board, and at the same time solve the problem of poor interlayer performance of the sandwich material.

[0051] In this embodiment, the weaving fibers of the hollow fabric 3 are one or more of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber, and the matrix is one of epoxy resin, phenolic resin, polyimide resin or silicon-containing arylene resin.

[0052] In some embodiments of the present invention, a metal mesh 4 is provided between and / or on the surface of the upper reinforcing layer 2 or the lower reinforcing layer 1.

[0053] In some embodiments of the present invention, the preparation materials of the metal mesh 4 include T2 copper wire mesh and / or stainless steel wire mesh.

[0054] The metal mesh 4 can be assembled and fixed by conductive adhesive, and the setting of the metal mesh 4 can enable the composite board to have a signal shielding function.

[0055] In some embodiments of the present invention, the composite board is integrally formed by a vacuum casting process.

[0056] In this embodiment, the material - structure form of the reinforcing fiber and the resin matrix improves the interlayer performance of the board and greatly improves the manufacturing efficiency at the same time.

[0057] As Figure 2 、 Figure 3a and Figure 3b shown, the embodiments of the present invention provide a structure, including a first composite board 100 and a second composite board 200. The first composite board 100 is any one of the above - mentioned composite boards. The first composite board 100 is rotatably connected to the fixing part 300, the second composite board is rotatably connected to the first composite board 100. The first composite board 100 is a flat board, the second composite board 200 is a board with an L - shaped cross - section and includes the fabric composite material. The first composite board 100 and the fixing part 300 are connected by a folding rod 400. The folding rod 400 includes a first rod body and a second rod body which are rotatably connected. The first rod body and the second rod body are respectively rotatably connected to the first composite board 100 and the fixing part 300. Power devices are connected to both ends of the rotation joints of the first rod body and the second rod body. The power devices are used to provide power to change the rotation angle of the rotation joints. The first composite board 100 and the second composite board 200 are connected by a telescopic rod 500 with a hydraulic or pneumatic system;

[0058] The first composite board 100 and the second composite board 200 are driven by driving the telescopic rod 500 and the folding rod 400.

[0059] In this embodiment, the first composite material board is the main load - bearing structure, which bears static and dynamic loads such as gravity, pressure, wind load, and shock. The overall rigidity and strength requirements are high; the second composite board 200 mainly considers its bending resistance and torsional resistance. By driving the telescopic rod 500 and the folding rod 400 to drive the first composite board 100 and the second composite board 200, the structure can be presented in an open state and a closed state. In the open state, at least 500 kg can be evenly loaded on the straight board, which can be used for stacking items and can also facilitate maintenance personnel to stand on it to repair internal components.

[0060] In this embodiment, the rotational connection can be achieved through a hinge 9.

[0061] In some embodiments of the present invention, a C-shaped frame 5 is provided around the first composite board 100. The four sides of the first composite board 100 are snapped into the grooves of the C-shaped frame 5, and the four C-shaped frames 5 are fixed by screwing. The distribution density of the pile warp of the hollow fabric 3 near the C-shaped frame 5 is higher than that in other positions.

[0062] The C-shaped frame 5 is made of aluminum alloy profile, stainless steel profile or carbon fiber profile. The four sides of the first composite board 100 are respectively assembled in the card slots of the C-shaped frame 5. The four C-shaped frames 5 are fixed by screwing, which improves the assembly reliability while reducing the process complexity and processing cost of the assembly process.

[0063] In some embodiments of the present invention, a hollow support rod 6 is inserted into the fabric composite material of the first composite board 100. The cross-section of the support rod 6 is rectangular, and the cross-section height of the support rod 6 is the same as the thickness of the fabric composite material, so that it is supported between the upper strengthening layer 2 and the lower strengthening layer 1. At the position where the hollow fabric is used to set the support rod 6, it is only interwoven with the warp and weft yarns at the surface layer to reserve a space for the insertion of the support rod 6.

[0064] The support rod 6 can be an aluminum alloy square tube, a stainless steel square tube or a fiberglass solid tube. The width of the cross-section of the tube is the same as the height of the core layer of the hollow fabric 3, and the cross-section length is generally about twice the width. The overall length is the same as the width of the board. At the same time, solid plugs are designed at both ends of the square tube and inserted into the core layer before the fabric is composite molded, and the distribution distance is 800-1000 mm. The embedding of the support rod 6 improves the overall rigidity and strength of the composite board, and also better controls the forming height of the hollow fabric 3.

[0065] In some embodiments of the present invention, a strip-shaped frame 7 for supporting the upper strengthening layer 2 and the lower strengthening layer 1 is provided around the second composite board 200, and the outside of the second composite board 200 is wrapped with an outer skin 8.

[0066] The strip-shaped frame 7 is formed by welding an aluminum alloy pultruded profile, a stainless steel pultruded profile or bonding a carbon fiber tube. The hollow board is embedded in the strip-shaped frame and assembled and fixed by a bonding process, and then the outer skin 8 is wrapped integrally.

[0067] According to the force characteristics of the board, the metal part frame is designed as a C-shaped frame 5 and a strip-shaped frame. While ensuring the bending resistance and torsional resistance, the C-shaped frame 5 further improves the overall rigidity and strength of the board parts, ensuring that the board will not deform during the opening and closing process under force. During the assembly process of the parts, installation holes such as hinges 9, telescopic rods 500, and folding rods 400 are processed on the metal parts, avoiding punching and assembling on the composite material, avoiding stress concentration and local damage of the overall structure, and improving the service life.

[0068] The outer skin 8 is a fiber-reinforced resin matrix composite material. The reinforcing body is one or more of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber, and the matrix is epoxy resin, phenolic resin, polyimide resin or silicon-containing aromatic acetylene resin. The outer skin 8 and the plate prepared by the above process are integrally wrapped with resin for secondary composite molding. The material-structure form of the reinforcing body fiber and the resin matrix improves the interlayer performance of the plate, and at the same time ensures the assembly reliability of the fabric composite material and the strip frame 7.

[0069] It should be noted that the mounting holes of the hinge 9, the telescopic rod 500 and the folding rod 400 are respectively processed at the C-shaped frame 5 and the strip frame 7, reducing the cracking of the hole position stress concentration and the deformation of the plate when the plate is opened and closed.

[0070] To better understand the present invention, the content of the present invention will be further clarified in combination with embodiments, but the content of the present invention is not limited to the following embodiments.

[0071] The specific molding process steps in this embodiment are as follows:

[0072] Preparation of the first composite plate:

[0073] (1) Cut a piece of E-glass fiber hollow fabric with a size of 1167mm×6440mm×22mm. There is a cavity with a length of 40mm every 800mm in the core layer of the fabric for inserting the support rod.

[0074] (2) The support rod is made of 5A05 aluminum alloy square tube, and solid plugs are welded at both ends of the square tube, with a size of 40mm×20mm×1166mm.

[0075] (3) Cut 16 layers of 200g / m 2 E-glass fiber cloth, lay 8 layers on each of the upper and lower surfaces of the hollow fabric respectively, and cut a 1167mm×6440mm T2 copper wire mesh and lay it in the middle of the 8 layers of fabric on the upper layer. At the same time, insert the support rod into the cavity of the core layer of the hollow fabric.

[0076] (4) Select epoxy resin and use the vacuum resin infusion molding process for composite molding. The curing process is 50°C×4h + 70°C×6h.

[0077] (5) Extrusion-mold aluminum alloy plates, and then use a CNC machine to machine C-shaped frames with slots. Four C-shaped frames are respectively opened with holes on both side walls at both ends for subsequent screw connection and fixation.

[0078] (6) Insert the corresponding sides of the composite plate formed in the above steps into the C-shaped frame slots, bond the three surfaces that fit the slots with conductive adhesive, and at the same time use bolts for screw connection and assembly fixation.

[0079] Preparation of the second composite plate:

[0080] (7) Cut a piece of conventional E-glass fiber hollow fabric with a size of 1400mm×6440mm×20mm, lay the hollow fabric on the forming mold, and at the same time lay a T2 copper wire mesh above the hollow fabric. Select epoxy resin and use the vacuum infusion molding process for composite molding. The curing process is 50℃×4h + 70℃×6h;

[0081] (8) Pultruded aluminum alloy plates, which have two long straight strips and two bent edge strips according to the appearance shape of the L-shaped plate. After CNC machining and welding, embed the hollow plate cured in the previous step into the bar-shaped frame, and use conductive adhesive to bond and fix the plate and the bar-shaped frame;

[0082] (9) Cut 4 layers of 200g / m 2 E-glass fiber cloth with a size of 1400mm×6440mm, and laminate it on the outer surface of the plate prepared in the above steps; at the same time, cut 4 layers of 200g / m2 E-glass fiber cloth with a size of 1450mm×6500mm, and laminate it on the inner surface and side of the plate. Select epoxy resin and use the hand lay-up molding process for composite molding. The curing process is 50℃×4h + 70℃×6h.

[0083] Assembly and coating:

[0084] (1) Machine the installation holes for hinges, telescopic rods and folding rods on both sides of the C-shaped frame and the bar-shaped frame respectively;

[0085] (2) For the machined composite material plate, after wiping the surface impurities of the plate with acetone, use 120# sandpaper to polish the metal surface, and at the same time use 240# sandpaper to polish the composite material surface, and then blow it clean with compressed air and wait for it to dry, so that the plate surface is clean, dry, free of particles and impurities;

[0086] (3) Prepare the anti-corrosion primer and spray it on the inner and outer surfaces of the plate. After spraying, let it stand at room temperature for about 30 minutes to ensure that the wet paint film is fully leveled and avoid blistering due to too fast temperature rise. Then heat it up to 50℃ and bake for 5 hours. The dry film thickness of the primer is about 40 - 60μm; after the primer is cured, use 240# sandpaper to polish the surface of the primer, prepare the electromagnetic shielding coating and spray it on the inner and outer surfaces of the plate. The curing method is the same as that of the primer, and the dry film thickness of the coating is about 100 - 120μm; similarly, after the electromagnetic shielding coating is cured, use 240# sandpaper to polish the surface of the coating, prepare the infrared stealth coating and spray it on the inner and outer surfaces of the plate. The dry film thickness of the coating is about 80 - 100μm.

[0087] (4) After the coating of the plate surface is completed, connect the flat plate and the L-shaped plate through hinges, and at the same time assemble the telescopic rod to ensure the mobility of the plate;

[0088] (5) Install the above-assembled components on the fixed part through a hinge and a folding rod, and control the opening and closing of the composite material plate components through a pneumatic system.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-performance lightweight composite sheet, characterized in that, It sequentially includes a lower strengthening layer (1) and an upper strengthening layer (2) along the thickness direction; The preparation materials of the upper strengthening layer (2) and the lower strengthening layer (1) both include fiber reinforced resin matrix composites. A fabric composite material is filled between the upper strengthening layer (2) and the lower strengthening layer (1). The fabric composite material is formed by a hollow fabric (3) and continuous metal wires through epoxy resin compounding.

2. The composite board according to claim 2, characterized in that, The reinforcing body of the fiber reinforced resin matrix composite includes one or more combinations of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber. The matrix of the fiber reinforced resin matrix composite includes epoxy resin.

3. The composite board according to claim 1, wherein The hollow fabric (3) is woven by one or more combinations of E-glass fiber, high-strength glass fiber, carbon fiber or aramid fiber.

4. The composite board according to claim 1, wherein, A metal mesh (4) is arranged between layers and / or on the surface of the upper strengthening layer (2) or the lower strengthening layer (1).

5. The composite board according to claim 1, wherein The preparation material of the metal mesh (4) includes T2 copper wire mesh and / or stainless steel wire mesh.

6. The composite board according to claim 1, characterized in that, The composite board is integrally formed by a vacuum resin infusion molding process.

7. A structure, characterized in that, It includes a first composite board (100) and a second composite board (200). The first composite board (100) is the composite board described in any one of claims 1-6. The first composite board (100) is rotatably connected to a fixing part (300). The second composite board is rotatably connected to the first composite board (100). The first composite board (100) is a flat board. The second composite board (200) is a board with an L-shaped cross-section and includes the fabric composite material. The first composite board (100) and the fixing part (300) are connected by a folding rod (400). The folding rod (400) includes a first rod body and a second rod body that are rotatably connected. The first rod body and the second rod body are respectively rotatably connected to the first composite board (100) and the fixing part (300). Power devices are connected to both ends of the rotational connection of the first rod body and the second rod body. The power device is used to provide power to change the rotation angle of the rotational connection. The first composite board (100) and the second composite board (200) are connected by a telescopic rod (500) with a hydraulic or pneumatic system; By driving the telescopic rod (500) and the folding rod (400) to drive the first composite board (100) and the second composite board (200).

8. A structure according to claim 7, characterized in that, A C-shaped frame (5) is arranged around the first composite board (100). The periphery of the first composite board (100) is inserted into the groove of the C-shaped frame (5). The four C-shaped frames (5) are fixed by screwing. The distribution density of the pile warp of the hollow fabric (3) near the C-shaped frame (5) is higher than that at other positions.

9. A structure according to claim 7, wherein A hollow support rod (6) is inserted into the fabric composite material of the first composite board (100). The cross-section of the support rod (6) is rectangular, and the cross-section height of the support rod (6) is the same as the thickness of the fabric composite material, so that it is supported between the upper strengthening layer (2) and the lower strengthening layer (1). At the position where the hollow fabric is used to set the support rod (6), it is only interwoven with the warp and weft yarns at the surface layer to reserve a space for inserting the support rod (6).

10. A structure according to claim 7, wherein, A strip-shaped frame (7) for supporting the upper strengthening layer (2) and the lower strengthening layer (1) is arranged around the second composite board (200), and the outside of the second composite board (200) is wrapped with an outer skin (8).

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