Preparation method and application of three-dimensional pyramid type composite material dot matrix sandwich structure

Abstract

The invention relates to the technical field of composite materials, in particular to a preparation method and application of a three-dimensional pyramid type composite material dot matrix sandwich structure.The preparation method comprises the steps that after a release agent is smeared on the surface of a panel mold and the surface of a sandwich mold, one-way prepreg is laid on a lower frame of the sandwich mold in a crossed mode, and the composite material dot matrix sandwich structure is obtained; laying panel prepreg on a panel mold, and demolding after hot pressing treatment to obtain a panel and a pyramid-shaped lattice structure core; the top and the bottom of the core of the lattice structure and the grooves are modified, the top and the bottom of the core are attached to and fixed to the two panels with the grooves respectively, and the three-dimensional pyramid type composite material lattice sandwich structure is obtained. The core with the pyramid-shaped lattice structure is formed under pressure by using the sandwich mold, and core fibers are continuous, so that the overall performance can be improved; and after the groove is formed by etching the panel, the core and the groove are modified, so that the surface roughness can be increased, and the interlocking mechanism is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a preparation method and application of a three-dimensional pyramid-shaped composite material lattice sandwich structure. Background Art

[0002] With the rapid development of aerospace technology, the demand for ultra-lightweight, high-strength, and multifunctional materials is becoming increasingly urgent. Composite lattice sandwich structures, as a new lightweight structural system, achieve a rational distribution of materials in three-dimensional space through topological optimization design. This structure, consisting of a core layer composed of periodically arranged micro-truss units and encapsulated by high-strength faceplates, exhibits significant advantages in specific strength, specific stiffness, energy absorption, and multifunctional integration. Its mechanical properties are primarily determined by the core topology, material composition matching, and interface bonding quality, and the fabrication process directly influences the degree to which these three elements are achieved. Research in this field has shifted from simple mechanical property prediction to the coordinated optimization of the entire chain of "design-preparation-performance". The current preparation of composite lattice sandwich structures mainly adopts split molding-gluing assembly or integrated molding / weaving process, but there are significant bottlenecks: the split process relies on gluing or mechanical connection, resulting in node weakening (the strength is only 30-50% of the continuous fiber structure) and interface defects (porosity 5-8%); integrated molding faces problems such as fiber breakage (fracture rate at the intersection of rods >20%) and low manufacturing efficiency (3D printing a single piece takes 8-12 hours).

[0003] These process defects result in a disconnect between structural performance and design goals, especially in terms of fiber continuity, interface bonding strength and gradient design, which make it difficult to meet the aerospace field's needs for lightweight, high reliability and multifunctional integration. There is an urgent need to develop breakthrough technologies such as continuous fiber molding, atomic-level interface modification and digital flexible manufacturing.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a preparation method and application of a three-dimensional pyramid-shaped composite material lattice sandwich structure, aiming to solve the problems of complex preparation process steps, low preparation efficiency and low structural strength in the existing preparation process.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure comprises the following steps:

[0008] Provide panel molds and sandwich molds;

[0009] After applying a release agent on the surface of the panel mold, the panel prepreg is laid, and after hot pressing, the panel is demoulded to obtain the panel;

[0010] After applying a release agent to the surface of the lower frame of the sandwich mold, unidirectional prepreg is cross-laid on the lower frame of the sandwich mold, covered with the upper frame of the sandwich mold, and demoulded after hot pressing to obtain a pyramid-shaped lattice structure core;

[0011] Etching the surface of the panel to obtain a panel with a plurality of grooves;

[0012] The top and bottom of the lattice structure core and the groove are modified, and the top and bottom of the lattice structure core are respectively bonded and fixed to two panels with grooves to obtain a three-dimensional pyramid-shaped composite material lattice sandwich structure.

[0013] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure, wherein, before applying the release agent to the surface of the panel mold and the sandwich mold, the panel mold and the sandwich mold are pretreated, and the pretreatment includes the steps of:

[0014] Performing etching and modification treatment on the panel mold and the sandwich mold by using plasma;

[0015] The panel mold and the sandwich mold after the etching modification treatment are cleaned by using an organic solvent to obtain the pretreated panel mold and the sandwich mold.

[0016] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure, wherein the temperature of the hot pressing treatment is 80°C-130°C, the time of the hot pressing treatment is 30min-50min, and the pressure of the hot pressing treatment is 1MPa-2MPa.

[0017] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure, wherein the hot pressing treatment includes: adjusting the hot press to keep warm at 80°C for 30 minutes, then heating to 130°C and pressurizing to 1MPa-2MPa and keeping warm for 60-90 minutes.

[0018] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure, wherein the number of layers of the unidirectional prepreg laid is 4-6.

[0019] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure, wherein the material of the panel prepreg is selected from one of carbon fiber, glass fiber, aramid fiber, and basalt fiber; the material of the unidirectional prepreg is selected from one of woven carbon fiber, glass fiber, and carbon fiber.

[0020] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure, wherein the etching treatment method includes one of plasma etching, laser etching, chemical etching, and corona treatment.

[0021] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure, wherein the top and bottom of the lattice structure core are respectively connected to the grooves of the panel; the connection method between the lattice structure core and the groove adopts one or more of bolt connection, rivet connection, and resin bonding.

[0022] The method for preparing the three-dimensional pyramid-shaped composite material lattice sandwich structure is as follows: the lower frame of the sandwich mold is provided with a plurality of three-dimensional pyramid-shaped laying parts arranged in a matrix, and the unidirectional prepreg is laid along the laying parts; the upper frame of the sandwich mold is provided with a pressure-applying part complementary to the three-dimensional pyramid-shaped laying parts, which is used to cooperate with the three-dimensional pyramid-shaped laying parts to achieve the shaping of the unidirectional prepreg; the sandwich mold also includes a lattice core base, and the base is provided with a plurality of support columns that can pass through adjacent three-dimensional pyramid-shaped laying parts.

[0023] A three-dimensional pyramid-shaped composite material lattice sandwich structure prepared by a method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure is used in aircraft, fan blades or electronic thermal management devices.

[0024] Beneficial effect: The present invention provides a preparation method and application of a three-dimensional pyramid-shaped composite material lattice sandwich structure. The preparation method of the three-dimensional pyramid-shaped composite material lattice sandwich structure includes the following steps: providing a panel mold and a sandwich mold; applying a release agent to the surface of the panel mold, laying a panel prepreg, and demolding after hot pressing to obtain a panel; applying a release agent to the surface of the lower frame of the sandwich mold, cross-laying unidirectional prepreg on the lower frame of the sandwich mold, covering the upper frame of the sandwich mold, and demolding after hot pressing to obtain a pyramid-shaped lattice structure core; etching the surface of the panel to obtain a panel with a plurality of grooves; modifying the top and bottom of the lattice structure core and the grooves, and respectively bonding and fixing the top and bottom of the lattice structure core to two panels with grooves to obtain a three-dimensional pyramid-shaped composite material lattice sandwich structure. The present invention utilizes a sandwich mold to form a pyramid-shaped lattice structure core under pressure, and the core fibers are continuous, which can improve the overall performance; and after etching the panel to form grooves, the core and the grooves are modified, the surface roughness can be increased, thereby enhancing the interlocking mechanism; at the same time, the modification treatment also improves the hydrophilicity of the surface, further optimizes the interfacial bonding performance, and significantly improves the bonding strength between the panel and the core; the lattice sandwich structure prepared by the preparation method has the characteristics of low density and high strength, and its lattice unit cell density can be flexibly adjusted to achieve functions such as gradient changes; in addition, the lattice core structure can be precisely controlled by adjusting the width and layer thickness of the unidirectional prepreg, thereby meeting the core size and performance requirements of different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic flow chart of a method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to the present invention;

[0026] Figure 2 Schematic diagram of the lower frame structure of the sandwich mold;

[0027] Figure 3 Schematic diagram of the upper frame structure of the sandwich mold;

[0028] Figure 4 It is a structural diagram of the lattice core base;

[0029] Figure 5 Schematic diagram of the three-dimensional structure of a pyramid-shaped core;

[0030] Figure 6 It is a front view of a pyramid-shaped core;

[0031] Figure 7 It is a side view of a pyramid-shaped core;

[0032] Figure 8 A top view of a pyramid-shaped core;

[0033] Figure 9 This is a schematic diagram of the unidirectional prepreg layup after the sandwich mold is assembled;

[0034] Figure 10 Schematic diagram of the panel structure after etching;

[0035] Figure 11 Schematic diagram of the explosion structure of a three-dimensional pyramid-shaped composite material lattice sandwich structure;

[0036] Figure 12 Schematic diagram of the overall structure of the three-dimensional pyramid-shaped composite material lattice sandwich structure. DETAILED DESCRIPTION

[0037] The present invention provides a method for preparing and applying a three-dimensional pyramid-shaped composite material lattice sandwich structure. To make the objectives, technical solutions, and effects of the present invention more clear and explicit, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0038] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0039] like Figure 1 As shown, the present invention provides a method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure, comprising the steps of:

[0040] Step S10: providing a panel mold and a sandwich mold;

[0041] Step S20: applying a release agent to the surface of the panel mold, laying the panel prepreg, and demoulding after hot pressing to obtain the panel;

[0042] Step S30: After applying a release agent to the surface of the lower frame of the sandwich mold, unidirectional prepreg is cross-laid on the lower frame of the sandwich mold, and the upper frame of the sandwich mold is covered. After hot pressing, the mold is demoulded to obtain a pyramid-shaped lattice structure core;

[0043] Step S40: etching the surface of the panel to obtain a panel with a plurality of grooves;

[0044] Step S50: modifying the top and bottom of the lattice structure core and the grooves, and respectively attaching and fixing the top and bottom of the lattice structure core to two panels with grooves to obtain a three-dimensional pyramid-shaped composite material lattice sandwich structure.

[0045] In this embodiment, a sandwich mold is used to form a pyramid-shaped core lattice structure under pressure, and the core fibers are continuous, which can improve the overall performance; after the panel is etched to form grooves, the core and grooves are modified, the surface roughness can be increased, thereby enhancing the interlocking mechanism; at the same time, the modification treatment also improves the hydrophilicity of the surface, further optimizes the interfacial bonding performance, and significantly improves the bonding strength of the panel pre-core; the lattice sandwich structure prepared by this preparation method has the characteristics of low density and high strength, and its lattice unit cell density can be flexibly adjusted to achieve functions such as gradient changes; in addition, the lattice core structure can be precisely controlled by adjusting the width and layer thickness of the unidirectional prepreg, thereby meeting the core size and performance requirements of different application scenarios.

[0046] Specifically, the preparation process of the lattice sandwich structure of the present invention adopts an automated laying process, which greatly reduces manual intervention and significantly improves production efficiency. At the same time, the modified treatment is adopted to achieve the integration of multiple functions such as cleaning treatment, surface modification and roughness control, effectively ensuring the consistency of product performance and the stability of quality, and providing reliable technical support for engineering applications. In addition, the three-dimensional pyramid-shaped composite material lattice sandwich structure prepared by this method has geometric topological characteristics, which has open holes and periodic arrangement, realizing efficient spatial distribution of materials, and its relative density can be reduced to 5%-20%; through continuous reinforcement and pressure forming process, the directional arrangement of fibers avoids the random defects of traditional foam core materials, and the strength utilization rate of fibers can reach more than 90% under axial load.

[0047] In some embodiments, before applying a release agent to the surfaces of the panel mold and the sandwich mold, the panel mold and the sandwich mold are pretreated. The pretreatment includes the steps of: etching and modifying the panel mold and the sandwich mold using plasma; and cleaning the etched and modified panel mold and the sandwich mold using an organic solvent to obtain the pretreated panel mold and the sandwich mold. The plasma etching and organic solvent cleaning can remove impurities on the surfaces of the panel mold and the sandwich mold, thereby achieving a cleaning effect.

[0048] Specifically, plasma (APPJ) is used to etch and modify the surfaces of the panel mold and the sandwich mold to clean the mold surface; then non-woven fabric dipped in acetone is used to clean impurities on the mold surface, and finally a release agent is evenly applied to the surface of the panel mold and the sandwich mold.

[0049] In some embodiments, the hot pressing treatment is performed at a temperature of 80° C. to 130° C., for a time of 30 min to 50 min, and at a pressure of 1 MPa to 2 MPa. The hot pressing treatment cures the panel prepreg and the unidirectional prepreg to obtain a panel and a pyramid-shaped core.

[0050] In a preferred embodiment, the hot pressing treatment includes: adjusting the hot press to maintain a temperature of 80° C. for 30 minutes, then heating to 130° C. and applying pressure to 1 MPa-2 MPa and maintaining the temperature for 60-90 minutes.

[0051] In some embodiments, in step S20, the panel prepreg is first cut to the same size as the panel mold using a CNC machine tool. After the panel prepreg is angled, the panel mold is placed in a hot press. The hot press is adjusted to maintain a temperature of 80°C for 30 minutes, then heated to 130°C and pressurized to 1MPa-2MPa for 80 minutes to produce the panel. This automated laying process significantly reduces manual intervention and significantly improves production efficiency.

[0052] In some embodiments, in step S30, the cut unidirectional prepreg is cross-laid on the lower frame of the sandwich mold in a woven structure in the horizontal direction. After laying two layers of prepreg, it is compacted using a silicone roller. After laying is completed, it is placed in the upper frame of the mold. Finally, the sandwich mold is placed in a hot press and pressurized for curing. The hot press is adjusted to keep warm at 80°C for 30 minutes, then heated to 130°C and pressurized to 1MPa-2MPa and kept warm for 80 minutes to obtain a pyramid-shaped lattice structure core.

[0053] In some embodiments, as Figure 2 As shown, the lower frame of the sandwich mold is provided with a plurality of three-dimensional pyramid-shaped laying portions 10 arranged in a matrix, and the unidirectional prepreg is laid along the laying portions; Figure 3 As shown, the upper frame of the sandwich mold is provided with a pressure portion complementary to the three-dimensional pyramid-shaped laying portion, which is used to cooperate with the three-dimensional pyramid-shaped laying portion to achieve the shaping of the unidirectional prepreg; Figure 4 As shown, the sandwich mold further includes a lattice core base, and the base is provided with a plurality of support columns 20 that can pass through between adjacent three-dimensional pyramid-shaped laying parts.

[0054] In some embodiments, the three-dimensional pyramid-shaped laying portion includes four support units, the support units are arranged in a "cross shape", and the angles between the support units are right angles; the four support units constitute a raised structure, and the support unit is inclined from the vertex of the raised structure to the point away from the vertex to form a pyramid shape, so that the unidirectional prepreg is laid along the edges of the support units. After hot pressing, a pyramid-shaped core can be obtained, and its three-dimensional structure schematic diagram is shown as follows Figure 5 As shown, the front view is as Figure 6 As shown, the side view is Figure 7 As shown, the top view is Figure 8 shown.

[0055] Specifically, through holes are provided between the three-dimensional pyramid-shaped paving parts, such as Figure 9 As shown, the lower frame of the sandwich mold is sleeved on the lattice core base, so that the support column passes through the through hole, and the lattice core base is used to apply uniform lateral pressure to the unidirectional prepreg, which is beneficial to the laying and positioning of the unidirectional prepreg.

[0056] In some embodiments, the number of layers of the unidirectional prepreg is 4-6, so that the pyramid-shaped core obtained after hot pressing has higher mechanical strength.

[0057] In some embodiments, the panel prepreg is made of a material selected from carbon fiber, glass fiber, aramid fiber, and basalt fiber; and the unidirectional prepreg is made of a material selected from woven carbon fiber, glass fiber, and carbon fiber. Panel prepregs and unidirectional prepregs made of these materials are low-cost and meet mechanical property requirements.

[0058] In some embodiments, the etching treatment includes one of plasma etching, laser etching, chemical etching, and corona treatment, such as Figure 10 As shown, etching the panel in the above manner can form a groove structure, so that the core can be accurately positioned and interlocked thereon, while increasing its surface roughness and surface activity.

[0059] In some embodiments, plasma etching technology is used to modify the top and bottom of the lattice structure core and the groove to increase their surface roughness and surface activity, thereby improving the adhesion between the core and the groove.

[0060] Specifically, by using plasma to etch the panel surface, and using plasma to modify the top and bottom of the lattice structure core and the groove, the corresponding groove pattern can be etched according to actual needs, and the surface roughness and hydrophilicity can be increased to ensure that the bonding strength between the panel pre-cores is significantly improved.

[0061] In some embodiments, as Figure 11 and Figure 12 As shown, the top and bottom of the lattice core are respectively connected to the grooves of the panel; the connection between the lattice core and the grooves is achieved by one or more of bolt connection, rivet connection, and resin bonding, thereby improving the disassembly and maintainability of the structure.

[0062] Specifically, a spraying device is used to evenly coat the prepared resin on the groove area of ​​the panel to ensure that the groove part is fully filled with resin, and the coating thickness is 0.05-0.2mm; for deeper groove areas, multiple coatings can be used to avoid insufficient resin or residual bubbles; the two panels are respectively pasted on the top and bottom of the pyramid core, and then the fixing device is placed outside the panel of the lattice core and at the diagonal of the panel, and pressed at room temperature for 4-6 minutes to shape it, and then placed in an oven and wait for the resin to solidify, that is, the lattice sandwich structure with the panel and the fixing device are placed in the oven and wait for the resin to solidify. The curing temperature is 120°C and the curing time is 120 minutes to obtain a three-dimensional pyramid-shaped composite material lattice sandwich structure.

[0063] In some embodiments, the resin includes one or more of epoxy resin, polyurethane resin, and phenolic resin, which can meet different requirements of mechanical properties and temperature resistance.

[0064] In some embodiments, the lattice cell density of the core can be flexibly adjusted through the design of the sandwich mold to achieve functions such as gradient changes to meet diversified engineering application needs.

[0065] In addition, the present invention also provides an application of a three-dimensional pyramid-shaped composite material lattice sandwich structure prepared by the preparation method of a three-dimensional pyramid-shaped composite material lattice sandwich structure in aircraft, fan blades or electronic thermal management devices.

[0066] In this embodiment, the three-dimensional pyramid-shaped composite material lattice sandwich structure prepared by the preparation method of the three-dimensional pyramid-shaped composite material lattice sandwich structure can be used in the fields of aircraft lightweight structure, transportation (lightweight components of automobiles and high-speed railways), energy (wind turbine blades), building protection, and electronic thermal management. Its unique periodic structure can not only improve the mechanical properties, but also integrate heat dissipation, wave absorption, sensing and other functions. In the future, it will develop in the direction of intelligence and multi-scale, and further expand its application potential in high-end equipment and new energy fields.

[0067] In summary, the present invention provides a preparation method and application of a three-dimensional pyramid-shaped composite material lattice sandwich structure. The preparation method of the three-dimensional pyramid-shaped composite material lattice sandwich structure includes the following steps: providing a panel mold and a sandwich mold; applying a release agent on the surface of the panel mold, laying a panel prepreg, and demolding after hot pressing to obtain a panel; applying a release agent on the surface of the sandwich mold, cross-laying unidirectional prepreg on the lower frame of the sandwich mold, covering the upper frame of the sandwich mold, and demolding after hot pressing to obtain a pyramid-shaped core; etching the surface of the panel to obtain a panel with a plurality of grooves; modifying the top and bottom of the lattice structure core and the grooves, and respectively bonding and fixing the top and bottom of the lattice structure core to two panels with grooves to obtain a three-dimensional pyramid-shaped composite material lattice sandwich structure. The present invention utilizes a sandwich mold to form a pyramid-shaped core lattice structure under pressure, and the core fibers are continuous, which can improve the overall performance; and after etching the panel to form grooves, the core and the grooves are modified, the surface roughness can be increased, thereby enhancing the interlocking mechanism; at the same time, the modification treatment also improves the hydrophilicity of the surface, further optimizes the interfacial bonding performance, and significantly improves the bonding strength between the panel and the core; the lattice sandwich structure prepared by the preparation method has the characteristics of low density and high strength, and its lattice unit cell density can be flexibly adjusted to achieve functions such as gradient changes; in addition, the lattice core structure can be precisely controlled by adjusting the width and layer thickness of the unidirectional prepreg, thereby meeting the core size and performance requirements of different application scenarios.

[0068] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure, characterized in that: Including steps: Provide panel molds and sandwich molds; After applying a release agent on the surface of the panel mold, the panel prepreg is laid, and after hot pressing, the panel is demoulded to obtain the panel; After applying a release agent to the surface of the lower frame of the sandwich mold, unidirectional prepreg is cross-laid on the lower frame of the sandwich mold, covered with the upper frame of the sandwich mold, and demoulded after hot pressing to obtain a pyramid-shaped lattice structure core; Etching the surface of the panel to obtain a panel with a plurality of grooves; The top and bottom of the lattice structure core and the groove are modified, and the top and bottom of the lattice structure core are respectively bonded and fixed to two panels with grooves to obtain a three-dimensional pyramid-shaped composite material lattice sandwich structure.

2. The method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to claim 1, wherein: Before applying the release agent to the surface of the panel mold and the sandwich mold, the panel mold and the sandwich mold are pretreated, and the pretreatment includes the following steps: Performing etching and modification treatment on the panel mold and the sandwich mold by using plasma; The panel mold and the sandwich mold after the etching modification treatment are cleaned by using an organic solvent to obtain the pretreated panel mold and the sandwich mold.

3. The preparation method of the three-dimensional pyramid type composite material lattice sandwich structure according to claim 1, wherein The temperature of the hot pressing treatment is 80° C.-130° C., the time of the hot pressing treatment is 30 min-50 min, and the pressure of the hot pressing treatment is 1 MPa-2 MPa.

4. The method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to claim 3, wherein: The hot pressing treatment includes: adjusting the hot press to keep the temperature at 80° C. for 30 minutes, then heating to 130° C. and applying pressure to 1 MPa-2 MPa and keeping the temperature for 60-90 minutes.

5. The method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to claim 1, wherein: The number of layers of the unidirectional prepreg is 4-6.

6. The method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to claim 1, wherein: The material of the panel prepreg is selected from one of carbon fiber, glass fiber, aramid fiber, and basalt fiber; the material of the unidirectional prepreg is selected from one of woven carbon fiber, glass fiber, and carbon fiber.

7. The method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to claim 1, wherein: The etching treatment method includes one of plasma etching, laser etching, chemical etching and corona treatment.

8. The method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to claim 1, wherein: The top and bottom of the lattice structure core are respectively connected to the grooves of the panel; the connection between the lattice structure core and the groove is achieved by one or more of bolt connection, rivet connection, and resin bonding.

9. The method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to claim 1, wherein: The lower frame of the sandwich mold is provided with a plurality of three-dimensional pyramid-shaped laying parts arranged in a matrix, and the unidirectional prepreg is laid along the laying parts; the upper frame of the sandwich mold is provided with a pressure-applying part complementary to the three-dimensional pyramid-shaped laying parts, which is used to cooperate with the three-dimensional pyramid-shaped laying parts to achieve the shaping of the unidirectional prepreg; the sandwich mold also includes a lattice core base, which is provided with a plurality of support columns that can pass through adjacent three-dimensional pyramid-shaped laying parts.

10. An application of a three-dimensional pyramid-shaped composite material lattice sandwich structure prepared by the method for preparing a three-dimensional pyramid-shaped composite material lattice sandwich structure according to any one of claims 1 to 9 in aircraft, fan blades or electronic thermal management devices.

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