Framework reinforced core material preparation method, corresponding core material and sandwich composite material

Abstract

The invention relates to a skeleton reinforced core material preparation method, a corresponding core material and a sandwich composite material, the skeleton reinforced core material is a sandwich in the sandwich composite material and comprises a skeleton and a matrix, the matrix is poured in a cavity constructed by the skeleton, and the skeleton comprises a contour structure and a supporting structure; the framework is provided with hollowed-out structures, crossed ribs are formed between the hollowed-out structures, and supporting structures are connected to the crossed points of the crossed ribs. By adopting the preparation method of the skeleton reinforced core material, the mechanical properties of the corresponding core material and the sandwich composite material can be remarkably improved, and the complex design requirements can be met more flexibly.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to a method for preparing a skeleton-reinforced core material, a corresponding core material, and a sandwich composite material. Background Art

[0002] The sandwich composite material adopts a "skin + core material + skin" sandwich structure form, and has high specific strength, high specific stiffness, non-magnetic property, excellent sound absorption and sound insulation performance, good vibration suppression effect, and excellent corrosion resistance characteristics. These advantages make it play an irreplaceable and important role in the development of ship technology. With the continuous increase of the working depth of ships, the ship field has an increasingly urgent need for lightweight, high-strength, and pressure-resistant core materials. However, the existing core materials of sandwich composite materials have obvious deficiencies. Specifically, the mechanical properties of the existing core materials cannot meet the requirements under the deep-sea high-pressure environment, and deformation or damage is likely to occur, affecting the safety and reliability of the overall structure. To meet the development needs of modern ship technology, it has become increasingly urgent to research and develop core materials with stronger mechanical properties, especially lighter and pressure-resistant ones. At the same time, the demand for material multi-functional integration also poses higher requirements for the design of core materials.

[0003] Chinese Patent CN117542911A discloses an edge-reinforced skeleton core material, an edge-reinforcement-free plate, and a photovoltaic module. The core material includes an integrally formed composite skeleton core layer. Among them, the skeleton core layer includes an edge skeleton core material part located in the outer peripheral region and a non-edge skeleton core material part located in the remaining non-outer peripheral region. It effectively reduces the edge deformation loss generated during subsequent composite processing, and further improves the packaging technology level of the photovoltaic module provided with the skeleton core layer structure. However, this core material cannot meet the requirements under the deep-sea high-pressure environment, and this method is not suitable for the preparation of high-strength core materials either.

[0004] Chinese Patent CN106626536A discloses a reinforced composite material foam sandwich cylinder and a preparation method thereof. The sandwich cylinder is composed of a composite material outer skin, a composite material inner skin, and a middle foam core layer. Grooves are engraved on both sides of the core layer, and composite material ribs are installed to enhance the structural strength. The core layer is made of foam material, and the core layer is formed by circumferentially splicing at least three foam arc pieces. A plurality of grooves are evenly distributed on the inner and outer surfaces of the core layer, and composite material ribs are installed in the grooves. The grooves and the composite material ribs are arranged along the axial direction of the core layer. Its preparation idea and method are different from those of the present invention, and it cannot meet the requirements for high strength and large load-bearing either. Summary of the Invention

[0005] In view of this, the present invention aims to provide a method for preparing a skeleton-reinforced core material, which significantly improves the mechanical properties of the core material and sandwich composite materials, meets the requirements for long-term use of composite materials under high water pressure conditions, and can more flexibly meet complex design needs.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A skeleton-reinforced core material, which is the core in a sandwich composite material, includes a skeleton and a matrix. The matrix is poured into the cavity formed by the skeleton. The skeleton includes a contour structure and a support structure; the skeleton is provided with a hollow structure, and cross ribs are formed between the hollow structures. The support structure is connected at the intersection points of the cross ribs. The skeleton is the basic framework of the core material, providing support and stability, and helping to maintain the shape of the core material. The contour structure is the main structure of the skeleton, forming the outer contour of the core material. The contour structure is connected to the support structure to form a complete support system. The hollow structure makes the core material structure stable and overall lightweight. Cross ribs are formed between the hollow structures, which can improve the support strength of the skeleton. The support structure is connected at the intersection points of the cross ribs, which is more conducive to force application and improves the support strength. Under the support of the skeleton, after pouring the matrix, the core material has the characteristics of high strength and low mass.

[0008] Further, the contour structure includes a first cover plate and a second cover plate, and the first cover plate and the second cover plate are connected by a support structure. The structure form of the first cover plate - support structure - second cover plate provides convenience for the manufacture of the skeleton on the one hand and takes into account the convenience of the design of the matrix pouring mold on the other hand.

[0009] Further, the support structure is columnar or plate-shaped. The columnar support structure is simple to manufacture and flexible and convenient to install; the plate-shaped support structure is an alternative to the columnar support structure, providing a better support effect.

[0010] Further, the support structure is connected to the contour structure in a concave-convex manner, making the connection positioning convenient and accurate.

[0011] Further, a structural functional unit is formed on the core material, and the structural functional unit is located at the hollow structure of the skeleton. The structural functional unit is used to endow the core material with special properties. It is arranged at the position of the hollow structure of the skeleton, making it have better structural support, so as to realize the multi-functional integrated design.

[0012] A method for preparing a skeleton-reinforced core material, which is used to produce the skeleton-reinforced core material as described above, includes a skeleton manufacturing process and a matrix pouring process. The skeleton manufacturing process is used to manufacture the skeleton, and the matrix pouring process is used to pour the matrix into the cavity.

[0013] Further, the skeleton manufacturing process includes the following steps:

[0014] S1: Fabricate the contour structure;

[0015] S2: Fabricate the support structure matching the contour structure;

[0016] S3: Connect the contour structure and the support structure to form the framework.

[0017] The framework fabricated by this process has stronger support ability.

[0018] Furthermore, the matrix casting process includes the following steps:

[0019] S1: Prepare the matrix casting mold;

[0020] S2: Configure the matrix;

[0021] S3: Place the fabricated framework in the matrix casting mold and cast the matrix on the framework;

[0022] S4: The matrix and the framework are combined and cured;

[0023] S5: Demold the core material and finish the surface.

[0024] Through this process, the matrix and the framework are combined into one body to complete the forming of the core material.

[0025] Furthermore, the matrix casting process includes fabricating the structural and functional unit. The structural and functional unit can be fabricated by die forming or machining methods, enabling the core material to have special properties while ensuring certain mechanical strength.

[0026] The present invention also discloses a sandwich composite material, which includes a core material fabricated by the method for preparing a framework-reinforced core material as described above. This sandwich composite material has stronger mechanical properties and can flexibly meet complex design requirements.

[0027] Compared with the prior art, the method for preparing a framework-reinforced core material and the corresponding core material and sandwich composite material of the present invention have the following advantages:

[0028] (1) The method of the present invention greatly improves the structural stiffness and strength of the core material, thereby improving the stability and reliability of the sandwich composite material product.

[0029] (2) The framework prepared by the present invention has strong designability, high machining preparation precision, simple forming process and convenient operation, enabling the product to achieve lightweight while meeting the dimensional and performance requirements.

[0030] (3) The present invention can use materials with higher strength as the framework, enabling a wider range of choices for the matrix.

[0031] (4) The present invention can achieve multi-functional integration by setting up structural and functional units, such as the collaborative optimization of acoustic performance and mechanical performance.

[0032] (5) The present invention can more flexibly meet the complex core material design requirements and is suitable for customized production. The present invention allows for flexible adjustment of the production process according to requirements, and selection of the most suitable materials and structures for each component, thereby achieving better performance matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0034] Figure 1 is a schematic structural diagram of the framework described in Embodiment 1 of the present invention;

[0035] Figure 2 is a schematic structural diagram of the framework described in Embodiment 2 of the present invention;

[0036] Figure 3 is a schematic structural diagram of the framework reinforcing core material described in Embodiment 2 of the present invention;

[0037] DESCRIPTION OF THE REFERENCE NUMERALS:

[0038] 1, first cover plate; 2, support structure; 3, second cover plate; 4, matrix; 5, structural and functional unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] In order to make the technical means, objectives and effects of the present invention easy to understand, the embodiments of the present invention will be described in detail below with reference to specific drawings.

[0040] It should be noted that all the terms indicating directions and positions in the present invention, such as: "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "inner", "outer", "top", "bottom", "lateral", "longitudinal", "center", etc., are only used to explain the relative positional relationship and connection situation between components in a certain specific state (as shown in the drawings), and are only for the convenience of describing the present invention, rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes and cannot be construed as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features.

[0041] In the description of the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", and "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components. 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.

[0042] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0043] Embodiment 1

[0044] A skeleton-reinforced core material, which is the core in a sandwich composite material, includes a skeleton and a matrix 4. The matrix 4 is cast in the cavity constructed by the skeleton. The skeleton includes a contour structure and a support structure 2; the skeleton is provided with a hollow structure, and cross ribs are formed between the hollow structures, and the support structure 2 is connected at the intersection points of the cross ribs. The skeleton is the basic framework of the core material, providing support and stability, and helping to maintain the shape of the core material. Under the support of the skeleton, after casting the matrix 4, the core material has the characteristics of high strength and low mass. The contour structure is the main structure of the skeleton, forming the outer contour of the core material. The contour structure is connected to the support structure 2 to form a complete support system. The connection between the contour structure and the support structure 2 can be a closed framework, or an open one, such as one end of the support structure 2 is connected and the other end is free. The connection method can be a fixed connection, a movable connection, etc. The hollow structure makes the core material structure stable and the whole lightweight. Cross ribs are formed between the hollow structures, which can improve the support strength of the skeleton. The support structure 2 is connected at the intersection points of the cross ribs, which is more beneficial for force bearing and improves the support strength.

[0045] A method for preparing a skeleton-reinforced core material, which is used to produce the above-mentioned skeleton-reinforced core material, includes a skeleton manufacturing process and a matrix casting process. The skeleton manufacturing process is used to manufacture the skeleton, and the matrix casting process is used to cast the matrix 4 into the cavity.

[0046] In Embodiment 1, the core material is a cylinder, and the composite material skeleton is a cylindrical structure.

[0047] Step 1: Manufacturing the skeleton process. Customize the skeleton according to the shape and structure characteristics of the core material. On the basis of meeting the product size and performance requirements, make it as lightweight as possible. Adopt the structural form of cover plate 1 - support structure 2 - cover plate 2 3. On the one hand, it provides convenience for manufacturing the skeleton, and on the other hand, it also takes into account the convenience of designing the matrix casting mold. The conventional plate-shaped or block-shaped core materials can all refer to the skeleton structural form of Embodiment 1.

[0048] Preferably, the skeleton is made of a fiber fabric reinforced resin matrix composite material, which can be formed by high-temperature curing of prepreg or vacuum-assisted molding of resin-injected reinforcing fibers. The preferred thickness of the skeleton is 2 - 200 mm.

[0049] S1: Manufacturing the contour structure. Make the contour structure with composite materials according to the shape and structure characteristics of the core material. The contour structure of the skeleton includes cover plate 1 and cover plate 2 3, both of which are provided with hollow structures. The hollow structures make the core material structure stable and the whole lightweight. Cross ribs are formed between the hollow structures of cover plate 1 and cover plate 2 3 to improve the support strength of the skeleton. According to the structural form of the skeleton, prepare fiber composite material plates with uniform thickness and certain dimensions, and form cover plate 1 and cover plate 2 3 of the skeleton through machining or laser engraving. Wipe off the oil stains and dust on the inner and outer surfaces of cover plate 1 with a clean rag.

[0050] The preferred thickness of cover plate 1 and cover plate 2 3 is 2 - 50 mm. The hollow structure can be circular, square or irregular in shape, etc.; its reinforcing material is preferably but not limited to fiber fabric, and the fabric structure includes but not limited to plain cloth, twill cloth, satin cloth and multi-axial warp knitted fabric; the resin matrix is epoxy resin or vinyl resin. For the curing of epoxy resin, amine curing agents are used; for vinyl resin, a peroxide and cobalt ion accelerator curing system is used; the fiber weight content is 50 - 65%.

[0051] Preferably, as Figure 1 shown, the skeleton has a cylindrical outer contour. Select epoxy resin prepreg and prepare a fiber composite material plate with a uniform thickness of 6 mm through high-temperature autoclave molding. Use a carving machine to process the composite material plate to form cover plate 1. The outer contour of cover plate 1 is a circular plate with an outer diameter of ø118 mm, and is provided with nine cubic hollow structures (27 mm × 27 mm × 8 mm). The hollow structures are arranged neatly, and cross ribs are formed between them. The width of the cross ribs is 8 mm, and the thickness is the same as that of the fiber composite material plate, both being 6 mm. The structural dimensions of cover plate 2 3 are the same as those of cover plate 1, and it is made by the same method.

[0052] S2: Fabricate the support structure 2 that matches the contour structure. According to the characteristics of the core material structure, a certain number of support structures 2 are fabricated using composite materials, preferably with a height of 2 - 100 mm. The first cover plate 1 and the second cover plate 3 are connected by the support structure 2 to form an integral whole. The support structure 2 can be columnar structures such as cuboids or cylinders. This setting makes the fabrication of the support structure 2 simple and the installation flexible and convenient.

[0053] Preferably, as Figure 1 shown, an epoxy resin prepreg is selected, and a fiber composite material plate with a uniform thickness of 8 mm is prepared by hot press molding in a high-temperature autoclave. According to the size of the hollow structure of the first cover plate 1, 12 cuboid-shaped support structures 2 are prepared, with dimensions of 8 mm (length) × 8 mm (width) × 29 mm (height).

[0054] S3: The contour structure of the framework is fixedly connected to the support structure 2, and the framework is formed. The fixed connection between the contour structure of the framework and the support structure 2 can be achieved by mechanical connection, adhesive connection, welding, etc. In Example 1, adhesive connection is used, and an adhesive is used for bonding.

[0055] The adhesive is configured in a certain proportion and stirred evenly with a stirrer and then set aside for use. The adhesive is in a liquid or viscous fluid structure and can be divided into two categories: organic adhesives and inorganic adhesives. It includes adhesives such as epoxy adhesives, silicone adhesives, polyimide adhesives, and phenolic resin adhesives. The configured adhesive is evenly applied to the bonding areas at the upper and lower ends of the support structure 2 and the bonding areas of the first cover plate 1 and the second cover plate 3. Using the support structure 2, the first cover plate 1 and the second cover plate 3 are bonded and fixed. The excess extruded adhesive is wiped off with a rag, and then the adhesive is waited to cure.

[0056] To facilitate the connection, a concave-convex groove structure can be set at the corresponding connection positions of the first cover plate 1 and the second cover plate 3 for connection and positioning with the support structure 2. The support structure 2 is connected to the intersection points of the cross ribs, which is more conducive to force bearing and improves the support strength.

[0057] Preferably, the configured adhesive is evenly applied to the upper and lower bonding end faces (8 mm × 8 mm) of the prepared support structure 2 and the cross rib area of the second upper cover plate 3. Using the support structure 2, the first cover plate 1 and the second cover plate 3 are bonded and fixed. The excess extruded adhesive is wiped off with a rag, and the adhesive is waited to cure naturally at room temperature for 24 h. The framework prepared by this method can withstand a compressive strength of not less than 20 MPa.

[0058] Second step: Matrix casting process. An injection mold is used to integrate the framework with the matrix 4 to form the core material.

[0059] S1: Prepare the matrix casting mold. According to the structural dimensions of the core material, prepare the corresponding matrix casting mold. The mold is prepared by machining, with structures such as exhaust holes and overflow grooves reserved. The materials used to prepare the mold are selected according to the actual usage, including but not limited to metal materials such as aluminum alloy, titanium alloy, and magnesium alloy, or non-metal materials such as acrylic and fiberglass.

[0060] S2: Configure matrix 4. Configure matrix 4 according to a certain proportion formula, stir it evenly with a stirrer, and then perform bubble extraction for standby. Matrix 4 is a liquid or viscous fluid structure formed by mixing matrix materials and fillers. Matrix materials include but not limited to polyurethane, epoxy resin, vinyl resin materials, etc. with a viscosity lower than 1200 mPa·s.

[0061] Preferably, configure matrix 4 according to a certain proportion formula. The proportion used in the formula refers to the ratio in the prior art. The fillers used are carbon aerosilica, glass flakes, vermiculite powder, carbon black, etc. Stir it evenly with a stirrer and then place it in a vacuum bubble extraction machine to extract bubbles and remove the bubbles in matrix 4.

[0062] S3: Place the prepared skeleton in the matrix casting mold and cast the skeleton with matrix 4. First, clean the inner surface of the prepared mold, apply a release agent or bond a self-adhesive release cloth, then place the prepared skeleton in the matrix casting mold, and then pour the configured matrix 4 into the mold. Continuously tap the mold wall with a rubber hammer to ensure that there are no bubble residues in the cast matrix 4. Install and fix the upper and lower covers of the mold, and wipe off the excess extruded matrix 4 with a rag.

[0063] S4: The combination of matrix 4 and the skeleton cures. According to the material characteristics of matrix 4, set appropriate temperature and time for curing. Check the curing progress to ensure that the material is completely cured.

[0064] Preferably, place the matrix casting mold together with the skeleton and matrix 4 in a corresponding high-temperature environment for curing. The curing temperature is 60°C - 200°C, and the curing duration is not less than 6 hours.

[0065] S5: Demold the core material and perform surface finishing. After curing, perform demolding, and repair the uneven areas of the molded core material to obtain the core material reinforced with the skeleton.

[0066] Example 2

[0067] A method for preparing a skeleton-reinforced core material for producing a skeleton-reinforced core material, including a skeleton manufacturing process and a matrix casting process. The skeleton manufacturing process is used to manufacture the skeleton, and the matrix casting process is used to pour matrix 4 into the cavity.

[0068] In Example 2, the core material is a hollow thick-walled cylinder, and the skeleton is a double-layer cylinder structure.

[0069] Step 1: Manufacturing the skeleton process. The conventional hollow structure core material can refer to the skeleton structure form of Embodiment 2.

[0070] S1: Manufacturing the contour structure. According to the outer shape structure characteristics of the core material, the contour structure is made of composite materials. The contour structure of the skeleton includes Cover Plate 1 and Cover Plate 3, both of which are hollow structures.

[0071] Manufacturing Cover Plate 1: Cover Plate 1 of the cylindrical structure skeleton is the outer side surface of the cylinder. Preferably, as Figure 2 shown, epoxy resin prepreg is selected, and a fiber composite material cylinder prepared by high-temperature autoclave molding has a length of 156 mm, a thickness of 8 mm, an inner diameter of ø340.5 mm, and an outer diameter of ø356.5 mm; a carving machine is used to process the composite material cylinder, so that 28×5 curved cube-shaped hollow structures are evenly distributed on the circumference of Cover Plate 1, that is, the number of hollow structures distributed in the circumferential direction of the cylinder is 28 columns, and the number of axially distributed is 5 rows; cross ribs are formed between the hollow structures, with a width of 8 mm and a thickness consistent with that of the fiber composite material cylinder, also 8 mm.

[0072] Manufacturing Cover Plate 3: Cover Plate 3 of the cylindrical structure skeleton is the inner side surface of the cylinder. Preferably, as Figure 2 shown, epoxy resin prepreg is selected, and a fiber composite material cylinder prepared by high-temperature autoclave molding has a length of 156 mm, a thickness of 8 mm, an inner diameter of ø266.5 mm, and an outer diameter of ø282.5 mm; a carving machine is used to process the composite material cylinder, so that 28×5 curved cube-shaped hollow structures are evenly distributed on the circumference of Cover Plate 3, that is, the number of hollow structures distributed in the circumferential direction of the cylinder is 28 columns, and the number of axially distributed is 5 rows; the hollow structures of Cover Plate 3 are arranged corresponding to those of Cover Plate 1; cross ribs are formed between the hollow structures, with a width of 8 mm and a thickness consistent with that of the fiber composite material cylinder, also 8 mm.

[0073] S2: Manufacturing the support structure 2 that matches the contour structure. Epoxy resin prepreg is selected, and a fiber composite material plate with a uniform thickness is prepared by high-temperature autoclave molding. According to the hollow structure size of the upper cover plate 3 of the fiber, a cuboid plate-shaped support structure 2 is prepared. Preferably, the support structure 2 has a length of 156 mm, a width of 29 mm, and a thickness of 8 mm, and 5 hollow structures are evenly distributed in the length direction, with a size of 29×26 mm. The hollow plate-shaped support structure is an alternative to the columnar support structure, providing a better support effect.

[0074] S3: The contour structure of the skeleton is fixedly connected to the support structure 2, and the skeleton is formed. The method is the same as that in Embodiment 1.

[0075] Step 2: Matrix casting process.

[0076] The steps and methods are the same as those in Embodiment 1.

[0077] For the core materials with special requirements, it is necessary to set up structural functional regions. By adjusting the structural form and size of the regions, the core materials can be given structural functionality. Filling appropriate materials in the structural functional regions can cooperate with the skin, achieving effects such as improving the heat insulation and sound insulation performance of the structure, increasing the compressive strength of the structure, and preventing local deformation. Setting the structural functional regions at the hollow structures of the framework enables the filler regions to have better structural support, thus enhancing the mechanical properties of the core materials as a whole.

[0078] In addition, in many engineering fields (such as aerospace, vehicle and ship industries, building acoustics), materials or structures not only need to have good acoustic properties (such as sound insulation, shock absorption), but also need to withstand certain mechanical loads (such as pressure, impact). Using porous materials is one of the important solutions. The existence of pores will affect the acoustic wave propagation characteristics of the materials, thereby improving their sound absorption, sound insulation or shock absorption performance. Through the interaction between the pores and air, porous materials convert sound energy into heat energy, thus reducing noise; appropriate pore distribution can change the propagation path of sound waves and increase the attenuation of sound waves; pores can disperse vibration energy and reduce the resonance effect. At the same time, pores can absorb impact energy and improve the impact resistance of the materials. However, the increase in porosity usually leads to a decrease in the strength and stiffness of the materials. By optimizing the pore layout (such as adopting a gradient pore structure), this problem can be alleviated to a certain extent, but still at the cost of losing some mechanical properties.

[0079] Under this requirement, the structure of the structural functional unit 5 + cross ribs + support structure 2 can solve the above contradictions. The structural functional unit 5 is located at the hollow structure of the framework, and the cross ribs and support structure 2 surround its outer periphery and are formed in the matrix. The cross ribs and support structure 2 are components of the framework, having relatively high strength and playing a supporting role in the form of the structural functional unit 5, thus improving the strength of the core materials. The structural functional unit 5 is the pore, ensuring the acoustic properties of the materials. This design method conforms to the idea of multi-functional integration design, facilitating the fabrication of new materials with both high strength and excellent acoustic properties.

[0080] Such as Figure 3As shown in the figure, at the hollow structure of the framework, several structural and functional units 5 are arranged on the inner and outer circumferential walls of the core material, which can realize the collaborative optimization of acoustic performance and mechanical performance. Its preferred form is a cylindrical blind hole. By adjusting the size, shape and distribution of the blind holes, the sound absorption performance can be optimized while ensuring a certain mechanical strength. The cylindrical design of the structural and functional unit 5 can disperse the sound wave reflection path and reduce the phenomenon of sound focusing. At the same time, the structural and functional unit 5 is arranged at the hollow structure of the framework, enabling the structural and functional unit 5 to have better structural support, adjusting the natural frequency and vibration mode of the structure, avoiding the occurrence of resonance, and achieving the best coupling between acoustic performance and mechanical performance.

[0081] In order to optimize acoustic performance and mechanical performance simultaneously, the following should be considered when designing the pore structure: adjusting the porosity, a larger porosity is conducive to the absorption of low-frequency sound waves, and a lower porosity can maintain a higher mechanical strength. Circular pores have less stress concentration and are suitable for application scenarios where mechanical performance is prioritized; connected pores contribute to the propagation and absorption of sound waves and are suitable for application scenarios where acoustic performance is prioritized. Adopting a gradient pore structure, a high porosity on the surface enhances the sound absorption performance, and a low porosity inside maintains the mechanical strength. In coordination with the pores, the shape and position of the hollow structure of the framework are adjusted accordingly to achieve mutual coordination.

[0082] The size, shape and distribution of the pores can be determined by establishing a mathematical model, considering both acoustic performance (such as transmission loss, noise level) and mechanical performance (such as stress, deformation) simultaneously, and using genetic algorithms or particle swarm optimization methods to find the optimal design solution.

[0083] When preparing the core material, before step S1 in the matrix casting process, step S0 can be set: designing the outer shape of the core material to form the structural and functional unit 5 on the core material, and casting and molding integrally through the matrix casting mold. Alternatively, after the core material is cast and molded, the structural and functional unit 5 can be added by machining.

[0084] A framework-reinforced core material is made by using the above-mentioned method for preparing a framework-reinforced core material. This core material has stronger mechanical properties and can flexibly meet complex design requirements.

[0085] A sandwich composite material is made by using the above-mentioned core material. This sandwich composite material has stronger mechanical properties and can flexibly meet complex design requirements.

[0086] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A skeleton-reinforced core material, characterized in that, The skeleton reinforcing core material is the core in the sandwich composite material, including a skeleton and a matrix (4). The matrix (4) is poured into the cavity formed by the skeleton. The skeleton includes a contour structure and a support structure (2); the skeleton is provided with a hollow structure, and cross ribs are formed between the hollow structures. The support structure (2) is connected at the intersection points of the cross ribs.

2. The skeleton reinforcing core material according to claim 1, characterized in that, The contour structure includes a first cover plate (1) and a second cover plate (3), and the first cover plate (1) and the second cover plate (3) are connected by the support structure (2).

3. The skeleton reinforced core material according to claim 1, characterized in that The support structure (2) is columnar or plate-shaped.

4. The skeleton reinforced core material according to claim 1, characterized in that, The support structure (2) is connected to the contour structure in a concave-convex manner.

5. The skeletal reinforcing core material according to claim 1, characterized in that, A structural functional unit (5) is formed on the core material, and the structural functional unit (5) is located at the hollow structure of the skeleton.

6. A method for preparing a skeleton-reinforced core material, characterized in that, The preparation method of the skeleton reinforcing core material is used to produce the skeleton reinforcing core material according to any one of claims 1-5, including a skeleton manufacturing process and a matrix pouring process. The skeleton manufacturing process is used to manufacture the skeleton, and the matrix pouring process is used to pour the matrix (4) into the cavity.

7. The method for preparing the skeleton reinforced core material according to claim 6, wherein The skeleton manufacturing process includes the following steps: S1: Manufacture the contour structure; S2: Manufacture the support structure (2) matching the contour structure; S3: Connect the contour structure and the support structure (2), and the skeleton is formed.

8. The method for preparing the skeleton-reinforced core material according to claim 6, characterized in that, The matrix pouring process includes the following steps: S1: Prepare a matrix pouring mold; S2: Configure the matrix (4); S3: Place the prepared skeleton in the matrix pouring mold, and pour the matrix (4) onto the skeleton; S4: The matrix (4) combines with the skeleton and cures; S5: Demold the core material and finish the surface.

9. The method for preparing the skeleton reinforced core material according to claim 8, wherein, The matrix pouring process includes manufacturing the structural functional unit (5) by using a mold forming method or a machining method.

10. A sandwich composite material, characterized in that, The sandwich composite material contains the core material manufactured by the preparation method of the skeleton reinforcing core material according to any one of claims 6-9.

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