A composite material integrated structure containing a connection joint and a preparation method thereof

Abstract

The present invention relates to a composite material integrated structure containing a connection joint, comprising a skin structure, a core material structure and a connection joint core material structure; one end of the connection joint core material structure is connected to the middle of the core material structure, and the other end is used to connect to the platform structure; the outer skin structure of the skin structure is laid on the outer wall surface of the core material structure, and the inner skin structure includes an interface reinforcement skin layer, a connection joint local reinforcement skin layer, and an integral inner skin layer laid in sequence from the outside to the inside, and the interface reinforcement skin layer is laid on the inner wall surface of the core material structure to separate the core material structure from the connection joint core material structure; the connection joint local reinforcement skin layer is laid on the surface where the core material structure and the connection joint core material structure are connected; the integral inner skin layer is laid on the surface of the core material structure and the connection joint core material structure, so that the connection becomes an integral structure. The present invention realizes the integration of structural manufacturing, improves the structural bearing performance, reduces the production and assembly of composite material components, and reduces labor and energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of ship composite materials, and in particular to a composite material integrated structure containing a connecting joint and a preparation method thereof. Background Art

[0002] In the design of ship structures, in order to improve the efficiency of the structure, the integrity of the structure is always the goal pursued by designers. Compared with segmented metal structures, composite materials have the advantage of improving the integrity of the structure. However, due to the needs or limitations of design, process, cost and maintenance, certain design and process separation surfaces must be arranged. The load transfer of these parts must be solved by corresponding connection methods, so structural connection is inevitable. The sealing, insulation, vibration reduction and fatigue resistance of adhesive connections meet the needs of ships and are suitable for the marine environment in which ships operate. In addition, composite structures have a long service life, low maintenance rate, and easy local maintenance and reinforcement, which can make up for the shortcomings of adhesive structures that cannot be disassembled. However, adhesive bonding has large strength dispersion, low peel strength, and is difficult to transmit large loads. Bolt connection is convenient for quality inspection and ensures the reliability of the connection. It can be assembled and disassembled repeatedly, but for sandwich structures with larger thickness, if bolt connection is used, the diameter of the bolt is larger, and the bolt opening not only destroys the continuity of the fiber, but also the stress concentration around the hole reduces the strength of the composite material. In addition, with the improvement of the preparation technology level of large composite structures and the requirements for structural integration, the use of T-type, π-type and L-type connectors and other structural forms has also been applied to ship composite structures, which has reduced the number of composite components and fasteners to a certain extent. However, for large composite structures, the more connectors there are, the greater the assembly workload will be, and the overall weight will also increase. In addition, the use of connectors for assembly is still insufficient in transmitting large loads, and there is also a gap with integrated manufacturing. Take the connection between the upper and lower bulkheads and decks of composite superstructures as an example. If a cross connector is used, it will involve the connection between the upper bulkhead and the cross connector, the connection between the lower bulkhead and the cross connector, and the connection between the deck and the cross connector. There are many connection nodes, the assembly workload is large, and the outer surface needs to be processed. If the structure has airtight and watertight requirements, the difficulty of assembly will be further increased, and the risk points of the structure will increase. In addition, due to the connection method, the upper bulkhead, lower bulkhead and deck can only be formed in blocks, and the manufacturing cost is high. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an integrated composite material structure containing a connecting joint and a preparation method thereof, in view of the problems of complex connection forms, large number of connecting parts, large assembly workload, great difficulty in tightness treatment, insufficient load transfer and high manufacturing cost of traditional composite material structures, so as to solve the connection problem between the upper and lower structures and the platform, realize the integration of structural manufacturing, improve the structural bearing performance, reduce the production and assembly of composite material components, and reduce labor and energy consumption.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is:

[0005] A composite integrated structure containing a connecting joint, comprising a skin structure, a core structure and a connecting joint core structure; one end of the connecting joint core structure is connected to the middle of the core structure, and the other end is used to connect to a platform structure; the skin structure comprises an outer skin structure and an inner skin structure, the outer skin structure is laid on the outer side wall surface of the core structure, the inner skin structure comprises an interface reinforced skin layer, a connecting joint local reinforced skin layer, and an integral inner skin layer laid in sequence from outside to inside, the interface reinforced skin layer is laid on the inner side wall surface of the core structure to separate the core structure from the connecting joint core structure; the connecting joint local reinforced skin layer is laid on the surface where the core structure and the connecting joint core structure are connected to improve the connection strength; the integral inner skin layer is laid on the surface of the core structure and the connecting joint core structure, so that the core structure and the connecting joint core structure are connected to form an integral structure.

[0006] In the above scheme, the core material structure includes a core material located in the middle and a first preform and a second preform respectively bonded to both ends of the core material, the first preform is used to connect with the top platform, and the second preform is used to connect with the bottom platform.

[0007] In the above solution, the core material is made of foam material; the first prefabricated part and the second prefabricated part are made of glass fiber reinforced plastic structure.

[0008] In the above solution, the connection interfaces between the first preform, the second preform and the core material are processed into a certain slope to increase the bonding strength.

[0009] In the above solution, the connecting joint core material structure includes a third prefabricated component and a supporting elbow structure, and the supporting elbow structure is bonded under the third prefabricated component.

[0010] In the above solution, the third prefabricated component adopts a glass fiber reinforced plastic structure, and the inner end of the third prefabricated component is processed into a step structure, which is matched with the platform structure and connected by glue screws.

[0011] In the above solution, the supporting elbow structure is made of foam material or composite material prefabricated parts.

[0012] In the above solution, the reinforcing material of the skin structure is selected from one of carbon fiber fabric, glass fiber fabric, carbon fiber prepreg and glass fiber prepreg.

[0013] In the above solution, the composite material integrated structure forming process adopts one of vacuum forming, OOA forming or autoclave forming processes.

[0014] Accordingly, the present invention also provides a method for preparing the composite material integrated structure containing the connection joint, comprising the following steps:

[0015] Mold preparation: clean the mold and apply release agent;

[0016] The outer skin structure is draped on the mold according to the designed number of fiber cloth layers, and then the core material structure is positioned and placed. Next, the interface reinforcement skin layer is draped on the surface of the core material structure, and then the connection joint core material structure is positioned and placed. Finally, the local reinforcement skin layer of the connection joint and the overall inner skin layer are draped in sequence.

[0017] Lay vacuum auxiliary materials on the entire preform and test the vacuum degree of the vacuum system;

[0018] Glue preparation and injection;

[0019] Curing and demoulding.

[0020] The beneficial effects of the present invention are:

[0021] The present invention utilizes the designability of composite materials, combines the manufacturing process level of large-scale composite materials, and through load analysis, structural design and simulation verification of composite materials, combined with the characteristics of sandwich structures, forms an integrated structure with composite materials skins on the inner and outer surfaces, and a core material and a composite material containing connecting joints in the middle, solves the connection problems between the upper and lower structures and the platform, realizes the integration of structural manufacturing, improves the structural bearing performance, reduces the production and assembly of composite materials components, and reduces labor and energy consumption.

[0022] Compared with the traditional connection method of connecting parts, the present invention can integrate the upper and lower bulkheads into an integrated structure, reduce the number of module molding and the connection between structures, and reduce the workload; the integrated structure avoids the problem of tightness between the outside and inside of the cabin; the integrated structure has high connection strength; in addition, the integrated structure has high surface quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0024] FIG1 is a schematic diagram showing the connection between a composite material integrated structure including a connecting joint and a platform structure according to the present invention.

[0025] In the figure: 10, skin structure; 11, outer skin structure; 12, inner skin structure; 121, interface reinforced skin layer; 122, local reinforced skin layer of the connecting joint; 123, integral inner skin layer;

[0026] 20. core material structure; 21. first prefabricated part; 22. core material; 23. second prefabricated part;

[0027] 30. Connecting joint core material structure; 31. Third prefabricated component; 32. Support elbow structure;

[0028] 200. Platform structure. DETAILED DESCRIPTION

[0029] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0030] As shown in FIG1 , a composite integrated structure containing a connecting joint is provided in an embodiment of the present invention, including a skin structure 10, a core structure 20 and a connecting joint core structure 30. One end of the connecting joint core structure 30 is connected to the middle of the core structure 20, and the other end is used to connect to the platform structure 200. The skin structure 10 includes an outer skin structure 11 and an inner skin structure 12. The outer skin structure 11 is laid on the outer wall surface of the core structure 20. The inner skin structure 12 includes an interface reinforced skin layer 121, a connecting joint local reinforced skin layer 122, and an integral inner skin layer 123 laid in sequence from the outside to the inside. The interface reinforced skin layer 121 is laid on the inner wall surface of the core structure 20 to separate the core structure 20 from the connecting joint core structure 30, forming a composite material interface, thereby improving the connection between the connecting joint and the upper and lower structures. Strength; the local reinforced skin layer 122 of the connecting joint is covered on the surface where the core structure 20 and the connecting joint core structure 30 are connected. Without changing the thickness of the inner skin structure 12 of the upper and lower structures, the local skin of the connecting structure is thickened according to the design to improve the connection strength; the overall inner skin layer 123 is covered on the surface of the core structure 20 and the connecting joint core structure 30, that is, it serves as the overall outer skin layer of the upper and lower structures and the connecting joint, so that the core structure 20 and the connecting joint core structure 30 are connected to form an integral structure.

[0031] Further optimization, the core material structure 20 includes a core material 22 located in the middle and a first preform 21 and a second preform 23 respectively bonded to the two ends of the core material 22. The core material 22 is made of foam material, which can reduce the weight of the structure while meeting the structural performance requirements, that is, achieve light weight and high strength of the structure. The first preform 21 is used at the tail end of the upper structure to replace the foam structure to form a solid composite material structure, which can be connected to the top platform to ensure the connection strength and avoid the risk of foam crushing and insufficient connection strength; the second preform 23 is used at the root of the lower structure to replace the foam structure to form a solid composite material structure, which can be connected to the bottom platform to ensure the connection strength and avoid the risk of foam crushing and insufficient connection strength.

[0032] Further optimization, the foam material is selected from one of PMI, PVC, HCP, and PET, preferably PVC foam, and the preferred material density is 50-200 kg / m 3 The upper and lower surfaces of the foam are provided with unidirectional grooves, the groove spacing is 20mm, the groove width is 2mm, and a through hole with a diameter of 2mm is drilled at the intersection of the grooves.

[0033] For further optimization, the first preform 21 and the second preform 23 are made of glass fiber reinforced plastics, which have high interlayer strength and are easy to process, while avoiding electrochemical corrosion problems caused by the connection between carbon fiber preforms and bolts.

[0034] For further optimization, the connection interfaces of the first preform 21, the second preform 23 and the core material 22 are all processed into a certain slope to increase the bonding strength, preferably 45 degrees.

[0035] Further optimized, the connecting joint core material structure 30 includes a third preformed component 31 and a supporting elbow structure 32 , and the supporting elbow structure 32 is bonded under the third preformed component 31 .

[0036] For further optimization, the third prefabricated component 31 adopts a glass fiber reinforced plastic structure, and the inner end of the third prefabricated component 31 is processed into a step structure, which is matched with the platform structure 200 and connected by glue screws. The glue adopts a flexible and detachable sealant to ensure the tightness of the connection structure.

[0037] Further optimization, the support elbow structure 32 is made of foam material or composite material prefabricated parts. According to the structural strength and weight requirements, the foam core material 22 can be preferably used. The structural outer surface of the support elbow structure 32 is selected from a straight line and an arc shape, and the arc shape is preferably more process-adaptable and aesthetically pleasing.

[0038] For further optimization, the reinforcing material of the skin structure 10 is selected from one of carbon fiber fabric, glass fiber fabric, carbon fiber prepreg, and glass fiber prepreg, and carbon fiber fabric and glass fiber fabric are preferred.

[0039] Further optimization, the composite material integrated structure molding process adopts one of vacuum molding, OOA molding or autoclave molding process, and vacuum molding is preferred based on the requirements of low manufacturing cost and high production efficiency of large structures. The matrix resin is selected from one of unsaturated polyester resin, epoxy resin and vinyl resin, and vinyl resin with good resistance to marine environment is preferred.

[0040] In this embodiment, the composite material integrated structure containing the connection joints is used as the upper and lower bulkheads of the superstructure, and the connection joints are used to connect the deck. Compared with the prior art in which the upper bulkhead, the lower bulkhead and the deck are formed in blocks, the present invention can form an integrated structure of the upper and lower bulkheads, reduce the number of module forming and the connection between structures, and reduce the workload; the integrated structure avoids the problem of tightness between the outside and inside of the cabin; the integrated structure has high connection strength; in addition, the integrated structure has high surface quality. Therefore, the present invention reduces the difficulty and workload of assembly, and further reduces the manufacturing cost. It should be noted that the outer profile of the integrated structure of the upper and lower bulkheads can be designed to any inclination angle according to actual needs, such as the inclination angle of 7° shown in Figure 1.

[0041] Accordingly, the present invention also provides a method for preparing the composite material integrated structure containing the connection joint, comprising the following steps:

[0042] Preparation of glass fiber reinforced plastic prefabricated parts: a first prefabricated part 21, a second prefabricated part 23 and a third prefabricated part 31 of designed thickness are prepared by using a vacuum integrated molding process, and are processed into required sizes.

[0043] Preparation of foam core material 22: Processing of core material 22 and supporting elbow structure 32 according to design dimensions.

[0044] Preparation of the core material structure 20: The processed core material 22 and the first preform 21 and the second preform 23 are bonded together using an adhesive, and then cured for later use.

[0045] Preparation of the connection joint core material structure 30: Adhesive is used to bond the processed support elbow structure 32 and the third prefabricated component 31, and the mixture is cured for later use.

[0046] Mold preparation: Clean the mold and apply release agent.

[0047] On the mold, the carbon fiber fabric covering of the outer skin structure 11 is completed according to the layup and the designed number of fiber cloth layers. During covering, the lap seams are staggered, the excess fibers are cut off, and then the bonded core material structure 20 is positioned and placed. Secondly, the carbon fiber fabric covering of the interface reinforced skin layer 121 is completed on the surface of the core material structure 20, and then the bonded connecting joint core material structure 30 is positioned and placed. Finally, the carbon fiber fabric covering of the connecting joint local reinforced skin layer 122 and the overall inner skin layer 123 is completed in sequence.

[0048] Lay vacuum auxiliary materials on the entire preform and test the vacuum degree of the vacuum system. The pressure range is required to be 0.095-0.1MPa after the vacuum pump works stably, and the pressure range is 0.090-0.1MPa after the vacuum pump is turned off and the pressure is maintained for 5 minutes.

[0049] Preparation of glue solution and injection: Determine the amount of glue to be used according to the results of the gel experiment, freeze the resin, control the temperature of the resin at 12-15℃ after mixing, mix the resin evenly, start the vacuum pump and inject the glue.

[0050] Curing, molding and demoulding: After the resin is poured, cure it at room temperature for 24 hours. Use a hardness tester to check the surface hardness of the cured resin. Demolding is performed when the Barcol hardness of at least two points reaches 35 or above.

[0051] After demoulding, the mold is polished to obtain a composite material integrated structure containing connection joints.

[0052] Finally, bolts are used to connect the composite material integrated structure including the connection joint to the platform structure 200 according to the design. Through testing, the designed composite material integrated structure including the connection joint and the platform structure 200 can bear a load greater than 30 kN.

[0053] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0054] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A composite material integrated structure containing a connection joint, characterized in that: It includes a skin structure, a core material structure and a connecting joint core material structure; the core material structure includes a core material located in the middle and a first prefabricated part and a second prefabricated part respectively bonded to the two ends of the core material, the first prefabricated part is used to connect with the top platform, and the second prefabricated part is used to connect with the bottom platform; the core material is made of foam material, and the first prefabricated part and the second prefabricated part are made of glass fiber reinforced plastic structure; the connection interfaces between the first prefabricated part, the second prefabricated part and the core material are processed into a certain slope to increase the bonding strength; the connecting joint core material structure includes a third prefabricated part and a supporting elbow structure, one end of the third prefabricated part is connected to the middle of the core material structure, and the other end is used to connect to the platform structure, and the supporting elbow structure is bonded to the bottom of the third prefabricated part; the third prefabricated part is made of glass fiber reinforced plastic structure, The inner end of the third prefabricated part is processed into a step structure, which is matched with the platform structure and connected by screws; the skin structure includes an outer skin structure and an inner skin structure, the outer skin structure is laid on the outer wall surface of the core structure, and the inner skin structure includes an interface reinforcement skin layer, a connection joint local reinforcement skin layer, and an integral inner skin layer laid in sequence from the outside to the inside, the interface reinforcement skin layer is laid on the inner wall surface of the core structure to separate the core structure from the connection joint core structure; the connection joint local reinforcement skin layer is laid on the surface where the core structure and the connection joint core structure are connected to improve the connection strength; the integral inner skin layer is laid on the surface of the core structure and the connection joint core structure, so that the core structure and the connection joint core structure are connected to form an integral structure.

2. The composite material integrated structure with connection joints according to claim 1, characterized in that: The supporting elbow structure is made of foam material or composite material prefabricated parts.

3. The composite material integrated structure with connection joints according to claim 1, characterized in that: The reinforcing material of the skin structure is selected from one of carbon fiber fabric, glass fiber fabric, carbon fiber prepreg and glass fiber prepreg.

4. The composite material integrated structure with connection joints according to claim 1, characterized in that: The composite material integrated structure forming process adopts one of vacuum forming, OOA forming or autoclave forming processes.

5. The method for preparing a composite material integrated structure containing a connection joint according to claim 1, characterized in that: The following steps are involved: Mold preparation: clean the mold and apply release agent; The outer skin structure is draped on the mold according to the designed number of fiber cloth layers, and then the core material structure is positioned and placed. Next, the interface reinforcement skin layer is draped on the surface of the core material structure, and then the connection joint core material structure is positioned and placed. Finally, the local reinforcement skin layer of the connection joint and the overall inner skin layer are draped in sequence. Lay vacuum auxiliary materials on the entire preform and test the vacuum degree of the vacuum system; Glue preparation and injection; Curing and demoulding.

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