Composite sandwich plate containing three-dimensional dot matrix core layer and manufacturing method of composite sandwich plate

Abstract

The invention discloses a composite sandwich plate containing a three-dimensional dot matrix core layer and a manufacturing method of the composite sandwich plate, and belongs to the technical field of composite sandwich structures. A three-dimensional bar system in the composite sandwich plate is obtained by improving and optimizing the height-width ratio of a body-centered cubic BCC bar system and adding an interface reinforcing bar system; through the design of an interface strengthening rod system and a novel interface combination method, high-strength connection of a three-dimensional dot matrix with a high surface area-volume ratio and a homogeneous solid panel is achieved. And the composite sandwich plate with high bearing capacity and strong combination is formed.

Description

Technical Field

[0001] This invention belongs to the field of composite sandwich structure technology, and particularly relates to a composite sandwich panel containing a three-dimensional lattice core layer and its manufacturing method. Technical Background

[0002] Additive manufacturing technology boasts advantages such as high precision, low cost, and rapid iteration. Various high-performance three-dimensional lattices have been extensively studied with the advancement of additive manufacturing technology, exhibiting superior lightweight, energy absorption, and thermal insulation properties compared to two-dimensional lattices. Additive manufacturing technology can be used to create more complex and specialized rod-like lattice structures, optimizing the area-to-volume ratio. Currently, there are relatively few cases of additive manufacturing three-dimensional lattices being applied to composite sandwich structures, and the composite methods, especially those for curved surface composite sandwich structures, have become key constraints on the development of this technology.

[0003] Sandwich structures, also known as sandwich structures, are high-performance, lightweight structures. Traditional sandwich structures consist of two thin panels and a thicker core layer. By combining the panels and the core material, structural performance can be significantly improved, and weight reduction can be achieved. Due to their lightweight and high strength, as well as the thermal insulation, sound insulation, and vibration isolation properties of the core material or structure, sandwich structures are widely used in explosion-proof structures, vehicles, ships, and aerospace fields.

[0004] Sandwich structures consist of a skin (high strength, high modulus, bearing tensile and compressive loads, resisting impact loads, and ensuring a smooth shape) and a core layer (lightweight, low modulus, mainly bearing shear loads and maintaining skin spacing) bonded together at an interface to form a synergistic load-bearing system. Their performance is highly dependent on the bonding quality between the core layer and the skin. Problems at the bonding interface not only directly weaken the structural load-bearing capacity but can also trigger a chain reaction of failures. Core layers (such as foam, honeycomb cores, and lattice cores) are mostly porous structures with a high surface area-to-volume ratio, while skin layers (such as carbon fiber composites and aluminum alloys) are mostly homogeneous solid structures with a low surface area-to-volume ratio. The effective contact area between the two is relatively small, making it difficult to form effective bonds and prone to shear failure. Summary of the Invention

[0005] This invention provides a composite sandwich panel with a three-dimensional lattice core layer and its manufacturing method, which achieves enhanced interfacial bonding between the skin and the core layer in the sandwich panel.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A composite sandwich panel containing a three-dimensional lattice core layer includes an outer skin, an adhesive reinforcement layer, and a three-dimensional lattice core layer; the upper and lower surfaces of the three-dimensional lattice core layer are adhesive reinforcement layers, and the outer side of the adhesive reinforcement layer is the outer skin.

[0007] The three-dimensional lattice core layer includes a three-dimensional rod system and an interface-reinforcing rod system; the interface-reinforcing rod system is located on the upper and lower surfaces of the three-dimensional rod system lattice and connects the nodes of the three-dimensional rod system. The interface-reinforcing rod system is a semi-circular tensile rod system, and one side of the plane formed by the semi-circular tensile rod system is an adhesive interface.

[0008] The described three-dimensional rod system is an improvement upon the body-centered cubic (BCC) rod system, with an optimized aspect ratio. The unit cell dimensions of the three-dimensional rod system are 15mm wide, 20mm high, and the rod diameter is 1.5mm. Under these geometric conditions, the minimum tilt angle of the BCC rod lattice is 43.31º. The minimum characteristics and maximum overhang angle of this geometry are suitable for various additive manufacturing technologies. The interface-reinforced rod system connects the upper and lower surface edge nodes of the three-dimensional rod system, providing deformation constraints and connection interfaces for the three-dimensional rod system. The interface-reinforced rod system and the three-dimensional rod system are combined to form a three-dimensional kagome rod system.

[0009] A method for manufacturing a composite sandwich panel containing a three-dimensional lattice core layer includes the following steps: The adhesive layer reinforcement layer is impregnated with high-performance resin using a vacuum diversion method; The structure is laid out in the following order: outer skin, adhesive reinforcement layer, three-dimensional lattice core layer, adhesive reinforcement layer, and outer skin, and then pre-compressed and shaped. The pre-compressed and shaped structure is subjected to vacuum compression, heating, and heat preservation operations. After heat preservation based on the resin's heat preservation time, the vacuum bag is removed to obtain a composite material sandwich structure.

[0010] In the steps described above, the adhesive reinforcement layer is cut according to the interface geometry of the interface reinforcement rod system; The three-dimensional dot matrix core layer is a three-dimensional dot matrix printed using additive manufacturing technology.

[0011] Beneficial effects: This invention provides a composite sandwich panel with a three-dimensional lattice core layer and its manufacturing method. The three-dimensional rod system in the composite sandwich panel is obtained by improving and optimizing the aspect ratio of the body-centered cubic (BCC) rod system and adding interface-strengthening rod systems. Through the design of the interface-strengthening rod system and a novel interface bonding method, a high-strength connection between the three-dimensional lattice with a high surface area-to-volume ratio and the homogeneous solid panel is achieved. This invention combines the improved and optimized lightweight three-dimensional lattice with the high-strength and high-rigidity composite panel to form a composite sandwich panel with high load-bearing capacity and strong bonding. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a curved composite material sandwich panel structure containing a three-dimensional lattice core layer in an embodiment of the present invention; Figure 2 This is a schematic diagram of the forming of a curved continuous fiber outer skin in an embodiment of the present invention; Figure 3 This is a schematic diagram showing the details of a curved composite sandwich panel structure containing a three-dimensional lattice core layer in an embodiment of the present invention. Figure 4 This is a schematic diagram of a three-dimensional rod lattice cell in an embodiment of the present invention; Figure 5 This is a schematic diagram of a planar composite sandwich panel structure containing a three-dimensional lattice core layer in an embodiment of the present invention; Figure 6 This is a cross-sectional view of the adhesive-reinforcing fabric after molding in an embodiment of the present invention; Figure 7 This is a diagram showing the results of a three-point bend test in Embodiment 2 of the present invention; Figure 8 This is a comparison diagram of the bending strength of Embodiment 2 of the present invention and the bending strength of a disclosed structure; In the diagram: S1 - Curved continuous fiber outer skin, S2 - Curved adhesive layer reinforcing fabric, S3 - Curved three-dimensional lattice core layer, S4 - Planar continuous fiber outer skin, S5 - Planar adhesive layer reinforcing fabric, S6 - Planar three-dimensional lattice core layer, P2 - Three-dimensional rod system, P1 - Interface reinforcing rod system, M1 - Upper mold of curved continuous fiber skin, M2 - Lower mold of curved continuous fiber skin. Detailed Implementation

[0013] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments: Example 1

[0014] This embodiment uses a curved composite sandwich panel as an example. like Figure 1 As shown, a curved composite sandwich panel with a three-dimensional lattice core layer includes a curved continuous fiber outer skin S1, a curved adhesive layer reinforcing fabric S2, and a curved three-dimensional lattice core layer S3. The curved continuous fiber outer skin S1 uses... Figure 2 The upper mold M1 and lower mold M2 of the curved continuous fiber skin are molded by compression molding. The curved three-dimensional lattice core layer S3 is an aluminum alloy kagome lattice structure with an added interface reinforcement rod system P1, printed using laser selective melting technology. The curved adhesive layer reinforcement fabric S2 is made from a single layer of orthogonal glass fiber cloth (single strand 2k filament) and is cut according to the surface shape of the interface reinforcement rod system P2 using a laser cutting machine.

[0015] The unit cell of the three-dimensional rod system P2 has dimensions of 15 mm width, 20 mm height, and a rod diameter of 1.5 mm. Under these geometric conditions, the minimum tilt angle of the rod lattice is 43.31º. 20 cells are arrayed along the length direction, 6 cells along the width direction, and 1 cell along the thickness direction. The lattice is bent at a center angle of R300 and 120 degrees.

[0016] The specific printing parameters for printing the curved 3D lattice core layer S3 using laser selective melting technology are as follows: laser power 300W, scanning speed 800mm / s, scanning spacing 0.1mm, powder particle size 20um, substrate preheating temperature 150 degrees Celsius, layer thickness 0.05mm, and argon protection.

[0017] In this embodiment, the upper mold M1 and the lower mold M2 of the curved continuous fiber skin are manufactured using melt extrusion technology to print high-temperature modified short-cut carbon fiber reinforced nylon material. The specific printing parameters are: nozzle diameter 0.6 mm, nozzle temperature 310 degrees Celsius, heated bed temperature 80 degrees Celsius, printing ambient temperature 60 degrees Celsius, outer wall speed 50 mm / s, filling speed 80 mm / s, number of outer wall layers 3, and filling density 25%. A layer of Teflon skin is laid on the working surfaces of the upper mold M1 and the lower mold M2 of the curved continuous fiber skin. Then, 16 layers of T800 continuous fiber unidirectional prepreg are laid on the working surface of the lower mold M2 of the curved continuous fiber skin, with the layering sequence being [45 / 0 / 90 / -45]4. The upper mold M1 of the curved continuous fiber skin is closed and vacuum extrusion is performed to shape it. The structure is heated together with the vacuum bag to 150 degrees Celsius and kept at that temperature for 1.5 hours. Then, it is naturally cooled to room temperature. After demolding, the curved continuous fiber outer skin S1 is obtained.

[0018] The manufacturing method of the above-mentioned curved composite sandwich panel containing a three-dimensional lattice core layer includes the following specific steps: The curved adhesive-reinforcing fabric S2 is impregnated with a prepared high-temperature epoxy resin; the structure is laid out in the following order: curved fiber outer skin S1, adhesive-reinforcing fabric S2, three-dimensional lattice core layer S3, curved adhesive-reinforcing fabric S2, and curved fiber outer skin S1, and pre-compressed and shaped; the pre-compressed and shaped structure is vacuum-compressed, and the structure is heated to 150 degrees Celsius along with the vacuum bag and kept at that temperature for 1.5 hours, and then naturally cooled to room temperature; the vacuum bag is removed to obtain the composite material sandwich structure.

[0019] It should be noted that the vacuum pump needs to be continuously connected throughout the entire process of heating and heat preservation in the vacuum bag to prevent the vacuum bag from depressurizing; the curved three-dimensional lattice core layer S3 must be able to withstand a pressure of 0.1 MPa at 150 degrees Celsius.

[0020] Example 2

[0021] This embodiment takes a planar composite sandwich panel as an example. like Figure 5As shown, a planar composite sandwich panel with a three-dimensional lattice core layer includes a planar continuous fiber outer skin S4, a planar adhesive layer reinforcing fabric S5, and a planar three-dimensional lattice core layer S6. The planar continuous fiber outer skin S4 is formed by hot pressing. The planar three-dimensional lattice core layer S6 is an aluminum alloy kagome lattice structure with an added interface reinforcing rod system P1, printed using laser selective melting technology. The planar adhesive layer reinforcing fabric S5 is made from a single layer of orthogonal glass fiber cloth (single strand 2k filaments) and cut using a laser cutting machine according to the surface shape of the interface reinforcing rod system P1.

[0022] The dimensions of the three-dimensional rod system P2 unit cell are 15 mm wide, 20 mm high, and the rod diameter is 1.5 mm. Under these geometric conditions, the minimum tilt angle of the rod lattice is 43.31º. Ten cells are arrayed in the length direction, four cells in the width direction, and one cell in the thickness direction.

[0023] The specific printing parameters for the laser selective sintering printing of the planar three-dimensional dot matrix core layer S6 are as follows: Laser power 300W, scanning speed 800mm / s, scanning spacing 0.1mm, powder particle size 20um, substrate preheating temperature 150 degrees Celsius, layer thickness 0.05mm, argon protection.

[0024] The planar continuous fiber outer skin S4 uses T800 continuous fiber unidirectional prepreg, laid in a layer sequence of [0 / 90]7, a total of 14 layers; the planar continuous fiber outer skin S4 is cured using a hot press at a temperature of 150 degrees Celsius and a pressure of 2 MPa for 0.5 hours, and then naturally cooled to room temperature; the planar continuous fiber outer skin S4 is obtained by CNC cutting.

[0025] The manufacturing method of the above-mentioned planar composite sandwich panel containing a three-dimensional lattice core layer specifically includes the following steps: Impregnate the planar adhesive-reinforcing fabric S5 with the prepared high-temperature epoxy resin; lay the structure in the following order: planar continuous fiber outer skin S4, planar adhesive-reinforcing fabric S5, planar three-dimensional lattice core layer S6, planar adhesive-reinforcing fabric S5, and planar continuous fiber outer skin S4, and pre-compress and shape it; vacuum-compress the pre-compressed and shaped structure, heat the structure together with the vacuum bag to 150 degrees Celsius, keep it at that temperature for 1.5 hours, and then let it cool naturally to room temperature. Remove the vacuum bag to obtain the composite sandwich structure.

[0026] The composite sandwich structure obtained above was subjected to a three-point bend test and compared with a structure with the same geometric conditions obtained by integral printing. The results are as follows: Figure 7As shown, the composite sandwich structures obtained by the method of this invention exceed the load-bearing capacity of integrated printed structures of the same geometric dimensions, demonstrating the reliability and excellent load-bearing capacity of the interface bonding method described in this invention. Furthermore, the composite sandwich structures obtained by this invention are lighter, with a load-bearing capacity 23.91%-37.56% higher than that of integrated structures, verifying the significant advantages of the interface bonding method described in this invention in terms of lightweighting.

[0027] The bending strength of the composite sandwich structure obtained above is compared with the bending strength of the disclosed structure, for example... Figure 8As shown, the publicly disclosed structures in the figure are: [1] from SJ Song, C. Xiong, JH Yin, HY Deng, KB Cui, C. Han, Flexural behavior, failure analysis, and optimization design of a hybrid composite Kagome honeycomb sandwich structure, Thin-WalledStruct, 187 (2023). http: / / dx.doi.org / 10.1016 / j.tws.2023.110743; [2] from H.-J.Um, N.-H. Jeon, J.-H. Shin, H.-S. Kim, High-performance multifunctional energy storage-corrugated lattice core sandwich structure via continuous carbon fiber (CCF) / polyamide 6 (PA6) 3D printing, Adv Compos Hybrid Mater, 6(5) (2023). http: / / dx.doi.org / 10.1007 / s42114-023-00761-x; [3] From CP Bai, HG Shi, Q. Yan, HY Cao, WY Bao, XF Li, et al., All-compositehoneycomb-enhanced corrugated hybrid structures to improve flexuralresponses, Compos Pt A-Appl Sci Manuf, 184 (2024).http: / / dx.doi.org / 10.1016 / j.compositesa.2024.108282; [4] From JX Zhang, YQ Zhu, H. Yuan, W.Huang, Failure behavior of sandwich beams with glass fiber-reinforced epoxy / aluminum laminates face-sheets and aluminum honeycomb core under three-point bending, Thin-Walled Struct, 177 (2022). http: / / dx.doi.org / 10.1016 / j.tws.2022.109476; [5] From F. K. Xia, Y. Durandet, P. J. Tan, D. Ruan, Three-point bending performance of sandwich panels with various types of cores, Thin-Walled Struct, 179 (2022). http: / / dx.doi.org / 10.1016 / j.tws.2022.109723; [6] From J. X. Zhang, W. Huang, H. Yuan, X. W. Wu, Failure behavior of a sandwich beam with GLARE face-sheets and aluminum foam core under three-point bending, Thin-Walled Struct, 183 (2023). http: / / dx.doi.org / 10.1016 / j.tws.2022.110438; [7] From X. J. Li, P. Qu, H. Kong, Y. H. Lei, A. F. Guo, S. Q. Wang, et al., Enhanced mechanical properties of sandwich panels via integrated 3D printing of continuous fiber face sheet and TPMS core, Thin-Walled Struct, 204 (2024). http: / / dx.doi.org / 10.1016 / j.tws.2024.112312; [8] From M. S. Haque, M. F. Hossain, M. S. Rana, M. S.Ferdous, Response of circular type sandwich panelizing JUCO-glass fiber with PU foam under three-point bending loading, ForcesMechanics, 17 (2024). http: / / dx.doi.org / 10.1016 / j.finmec.2024.100290; [9] From D. Arslan, M. Mihai, D. Therriault, M. Lévesque, Flexural properties of sandwich panels fabricated by filament-extrusion of high-temperaturethermoplastic composites, Compos Sci Technol, 263 (2025). http: / / dx.doi.org / 10.1016 / j.compscitech.2025.111106;

[10] From X. Zhang, CX Xu, W. Li, ZMSu, Study on the bending and shear properties of quasi-honeycomb sandwichstructures considering the variable-density core design, Compos Struct, 324(2023).http: / / dx.doi.org / 10.1016 / j.compstruct.2023.117517; from. Figure 8 As can be seen from the present invention, the sandwich structure prepared by the method of the present invention has a slightly lower bending strength than the traditional pure carbon fiber sandwich structure under the same equivalent density [1]-[3]. However, compared with the expensive preparation cost and long processing time of the traditional carbon fiber sandwich structure, the method of the present invention has a greater manufacturing advantage and flexibility for large-scale application. The sandwich structure prepared by the method of the present invention has better equivalent density and bending strength than other disclosed aluminum-aluminum sandwich structures [4]-[6] and two-dimensional lattice composite structures [7]-

[10] , indicating that the structure of the present invention has excellent lightweight effect and the interface bonding method of the present invention is efficient and reliable.

[0028] The above are merely preferred embodiments of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A composite sandwich panel containing a three-dimensional lattice core layer, characterized in that, It includes an outer skin, an adhesive reinforcement layer, and a three-dimensional lattice core layer; the upper and lower surfaces of the three-dimensional lattice core layer are adhesive reinforcement layers, and the outer side of the adhesive reinforcement layer is the outer skin; the three-dimensional lattice core layer is provided with an interface reinforcement layer connected to the adhesive reinforcement layer.

2. The composite sandwich panel containing a three-dimensional lattice core layer according to claim 1, characterized in that, The three-dimensional lattice core layer includes a three-dimensional rod system and an interface-reinforced rod system; the interface-reinforced rod system is located on the upper and lower surfaces of the three-dimensional rod system lattice, connecting the three-dimensional rod system nodes, and providing deformation constraints and connection interfaces for the three-dimensional rod system.

3. The composite sandwich panel containing a three-dimensional lattice core layer according to claim 2, characterized in that, The interface reinforcement rod system is a semi-circular tension rod system, and one side of the plane formed by the semi-circular tension rod system is the adhesive interface.

4. The composite sandwich panel containing a three-dimensional lattice core layer according to claim 2, characterized in that, The three-dimensional bar system is obtained by improving and optimizing the aspect ratio of the body-centered cubic (BCC) bar system.

5. The composite sandwich panel containing a three-dimensional lattice core layer according to claim 2 or 4, characterized in that, The minimum tilt angle of the three-dimensional rod lattice is 43.31º.

6. The composite sandwich panel containing a three-dimensional lattice core layer according to claim 5, characterized in that, The unit cell of the three-dimensional rod system has a width of 15mm, a height of 20mm, and a rod system diameter of 1.5mm.

7. A method for manufacturing a composite sandwich panel containing a three-dimensional lattice core layer as described in any one of claims 1-6, characterized in that, Includes the following steps: The adhesive layer reinforcement layer is impregnated with high-performance resin using a vacuum diversion method; The structure is laid out in the following order: outer skin, adhesive reinforcement layer, three-dimensional lattice core layer, adhesive reinforcement layer, and outer skin, and then pre-compressed and shaped. The pre-compressed and shaped structure is subjected to vacuum compression, heating, and heat preservation operations; After heat preservation based on the resin's heat preservation time, the vacuum bag is removed to obtain a composite material sandwich structure.

8. The method for manufacturing a composite sandwich panel containing a three-dimensional lattice core layer according to claim 7, characterized in that, The adhesive reinforcement layer is cut according to the interface geometry of the interface reinforcement rod system.

9. The method for manufacturing a composite sandwich panel containing a three-dimensional lattice core layer according to claim 7, characterized in that, The three-dimensional dot matrix core layer is a three-dimensional dot matrix printed using additive manufacturing technology.

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