A lightweight impact-resistant composite material plate with a microstructure imitating hedgehog spines and a preparation method thereof

Abstract

The invention discloses a lightweight impact-resistant composite material plate with a hedgehog-thorn-like microstructure and a preparation method thereof. The lightweight impact-resistant composite material plate with a hedgehog-thorn-like microstructure comprises: a porous structure core layer composed of transverse reinforcing ribs and longitudinal reinforcing ribs and an upper and lower panel structure. The porous structure core layer adopts a short fiber epoxy resin material, and the upper and lower panels adopt a mixed fiber epoxy resin material with a variable modulus and a variable density. The upper and lower panels adopt a fiber ply design. The overall structure is prepared by 3D printing and one-piece molding to form a bionic porous structure composite sandwich panel. Compared with a traditional sandwich panel structure, the specific stiffness and specific strength thereof are further improved, the local stress concentration caused by the sudden change of properties of heterogeneous materials is alleviated, and the problem of debonding and fracture of the interface between the upper and lower panels and the core layer due to stress concentration and premature damage and failure is solved.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a lightweight impact-resistant composite material plate with a hedgehog-bone-imitation microstructure and a preparation method thereof. Background Art

[0002] In recent years, China's rail passenger cars have been continuously updated. The requirements for performance improvement of key components in the passenger compartment interior structure of rail passenger cars, such as floors, side wall panels, inner roof panels, partition panels, inner and outer door panels, etc., are increasing, which puts forward new requirements for the structural design of key components in the passenger compartment interior structure.

[0003] The traditional sandwich panel structure is a structural material composed of two layers of high-strength, high-modulus thin panels and a thicker lightweight core material in the middle. The role of the lightweight core is to reduce the weight of the structure as much as possible, increase the section inertia moment of the two panels, and thus improve the bending stiffness of the structure. The panels are bonded to the core to achieve the transfer of loads between the core and the panels. The lightweight core mainly bears out-of-plane shear loads, while the panels mainly bear in-plane loads and bending loads. Compared with ordinary single materials, the sandwich panel structure has the characteristics of high specific strength and high specific stiffness, but it also has some inevitable defects. One of the important ones is that when the panel is subjected to low-speed impact, the panel and the core cannot be welded together intact, causing the welds to be detached at the welds between the panel and the core, thereby greatly reducing the mechanical properties of the structure. Therefore, it is urgent to find a method that can make the panel have high specific strength and specific stiffness while meeting the low-speed impact resistance performance.

[0004] That is, in the conventional sandwich panel structure in the prior art, stress concentration will occur at the interface due to the sudden change in the properties of the heterogeneous materials when subjected to force. The large stress here will cause the material to crack first and the overall structure to fail prematurely, resulting in the problem of debonding and fracture of the interface between the panel and the core when subjected to low-speed impact in the conventional sandwich panel structure.

[0005] Therefore, the existing technology still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a lightweight impact-resistant composite material plate with a hedgehog-like microstructure and a preparation method thereof, aiming to solve the problem of debonding and fracture at the interface between the panel and the core when subjected to low-speed impact in the existing traditional sandwich panel structure.

[0007] The technical solution of the present invention is as follows:

[0008] A lightweight impact-resistant composite material plate with a microstructure imitating hedgehog thorns, wherein the overall structure of the lightweight impact-resistant composite material plate with a microstructure imitating hedgehog thorns comprises:

[0009] A porous core layer composed of transverse and longitudinal reinforcement ribs;

[0010] An upper panel, the upper panel being arranged on the upper surface of the porous structure core layer;

[0011] A lower panel, the lower panel being arranged on the lower surface of the porous structure core layer;

[0012] The porous core layer adopts a hedgehog-like hard thin shell-flexible porous core layer structure; the upper panel and the lower panel adopt a composite material plate with a hedgehog-like outer shell fiber laying method, and the upper panel and the lower panel adopt a fiber laying arrangement;

[0013] The overall structure of the lightweight impact-resistant composite material plate imitating the hedgehog spine microstructure is prepared by 3D printing and integrated molding to form a bionic porous structure composite material sandwich plate.

[0014] The lightweight impact-resistant composite material plate with a hedgehog-like microstructure, wherein the porous structure core layer is made of a short-fiber epoxy resin material core layer, and the upper panel and the lower panel are made of a mixed fiber epoxy resin material plate with a variable modulus and density.

[0015] The lightweight impact-resistant composite material plate with a hedgehog-like microstructure, wherein the ratio of the thickness of the transverse reinforcing ribs of the porous structure core layer, the spacing between the transverse reinforcing ribs, and the thickness of the upper and lower panels is 1:7.54:5.8.

[0016] The lightweight impact-resistant composite material plate imitating hedgehog thorn microstructure, wherein the porous structure core layer is formed by 3D printing of fiber hybrid composite material, and the specific modulus of the porous structure core layer is 0.29*10 5 MPa.

[0017] The lightweight impact-resistant composite material plate with a hedgehog-like microstructure, wherein the upper panel and the lower panel are divided into a first layer, a second layer, and a third layer from the outside to the inside, and are a fiber laying model for imitating the outer shell of a hedgehog.

[0018] The lightweight impact-resistant composite material plate with a hedgehog-like microstructure, wherein the first layer, the second layer, and the third layer are each composed of a plurality of variable-angle fiber layers, a single fiber layer in the variable-angle fiber layers contains a plurality of fibers, the plurality of fibers are laid straight and parallel in the same direction, and the single fiber layers are connected by resin curing.

[0019] The lightweight impact-resistant composite material plate imitating the hedgehog thorn microstructure, wherein the first layer is composed of a specific modulus of (2.0-2.34)*10 5 MPa high modulus carbon fiber is staggered at 0°, ±45°, and 90°. The second layer is composed of a specific modulus of 0.58*10 5MPa K-49Ⅳ aramid fiber is staggered at 0°, ±45°, and 90°. The third layer is composed of a specific modulus of 0.29*10 5 MPa E glass fibers are staggered at 0°, ±45°, and 90°, and the fiber arrangement density of the first, second, and third layers decreases from the outside to the inside.

[0020] The lightweight impact-resistant composite material plate with a hedgehog-like microstructure, wherein the thickness ratio of the upper panel, the porous structure core layer and the lower panel is 1:16:1.

[0021] A method for preparing a lightweight impact-resistant composite material plate with a hedgehog-like microstructure as described in any one of the above, comprising the steps of:

[0022] A: pre-inputting a three-dimensional model of a lightweight impact-resistant composite material plate with a microstructure imitating hedgehog spines on a fiber 3D printer, and pre-setting the materials of the upper panel, the core layer and the lower panel;

[0023] B: Prepare the lower panel by printing layer by layer through a fiber 3D printer: first replace the printing material of the 3D printer with resin-based carbon fiber to print the first layer S1 of the lower panel, then replace the printing material of the 3D printer with resin-based aramid fiber to print the second layer S2 of the lower panel, and then replace the printing material of the 3D printer with resin-based E-glass fiber to print the third layer S3 of the lower panel, so as to prepare a new type of composite material board with variable modulus and variable density imitating the hedgehog thorn shell fiber layout method, and form the preparation of the upper panel;

[0024] C: replacing the printing material of the 3D printer with epoxy resin mixed with short fiber material, using short fiber epoxy resin material to prepare the porous structure core layer by a fiber 3D printer;

[0025] D: Prepare to prepare the upper panel, print layer by layer through a fiber 3D printer, first replace the printing material of the 3D printer with resin-based carbon fiber to print the first layer S1 of the upper panel, then replace the printing material of the 3D printer with resin-based aramid fiber to print the second layer S2 of the upper panel, and then replace the printing material of the 3D printer with resin-based E glass fiber to print the third layer S3 of the upper panel, so as to prepare a new type of composite material board with variable modulus and variable density imitating hedgehog thorn shell fiber layout on the prepared porous structure core layer to prepare the upper panel.

[0026] The preparation method, wherein the upper panel and the lower panel are prepared into a first layer, a second layer, and a third layer from the outside to the inside, which is a fiber laying model imitating the outer shell of a hedgehog thorn, and the density of the first layer, the second layer, and the third layer is controlled by the printed fiber content, and the fiber content gradually decreases from the outside to the inside; the upper panel, the lower panel and the porous structure core layer sandwiched in the middle are prepared by 3D printing as a whole.

[0027] Beneficial effects: The present invention provides a lightweight impact-resistant composite material plate with a hedgehog-like microstructure and a preparation method thereof, provides a design and integrated printing technology for a hybrid fiber ply panel and a porous core layer with transverse and longitudinal reinforcement ribs, and through a bionic porous structure and a unique hybrid fiber bundle arrangement method, the sandwich fiber composite material plate structure has high specific strength and high specific stiffness. At the same time, when subjected to a low-speed impact, the debonding and fracture damage due to stress concentration at the interface between the panel and the core can be avoided. This new structural composite material can meet the higher requirements of key components such as floors, side wall panels, inner roof panels, partition panels, and door panels of inner and outer doors in the interior decoration structure of Chinese rail passenger cars: it has excellent mechanical properties of light weight, high strength, high fracture toughness, and resistance to low-speed impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a schematic structural diagram of a lightweight impact-resistant composite material plate with a hedgehog-bone-mimicking microstructure according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the external hedgehog spine shape of a hedgehog.

[0030] Figure 3 This is a SEM schematic diagram of the longitudinal section of the center of the hedgehog spine.

[0031] Figure 4 This is a SEM schematic diagram of the longitudinal section of the hedgehog spine.

[0032] Figure 5 Schematic diagram of SEM images of the cross-section and longitudinal sections of hedgehog spines.

[0033] Figure 6 Schematic diagram of the SEM image of the hedgehog spine shell.

[0034] Figure 7 Schematic diagram of a further enlarged SEM image of the hedgehog spine shell.

[0035] Figure 8 Schematic diagram of the change in elastic modulus of the hedgehog spine shell measured by nanoindentation from the outside to the inside.

[0036] Fig. 9 It is a schematic diagram of a three-dimensional model of a hedgehog-like thorn structure and a comparative structure of a lightweight impact-resistant composite material plate with a hedgehog-like thorn microstructure according to an embodiment of the present invention.

[0037] Fig.10 Schematic diagram of stress contour lines and contour surfaces for comparing low-speed impact simulation of structural models.

[0038] Fig.11 A schematic diagram of low-speed impact simulation stress contour lines and contour surfaces of a hedgehog-like thorn structure model of a lightweight impact-resistant composite material plate with a hedgehog-like thorn microstructure according to an embodiment of the invention.

[0039] Fig.12 Schematic diagram of the comparison of the low-speed impact simulation specific stress between the comparison structure model and the hedgehog-like structure model.

[0040] Fig.13 Schematic diagram of the comparison of deformation between the comparison structure model and the hedgehog-like structure model under low-speed impact simulation.

[0041] Fig.14 The present invention is a schematic front view of a structural model of a hedgehog-like composite material plate having a lightweight impact-resistant composite material plate with a hedgehog-like microstructure according to an embodiment of the present invention.

[0042] Fig.15 The present invention is a schematic side view of a structural model of a hedgehog-like composite material plate of a lightweight impact-resistant composite material plate with a hedgehog-like microstructure according to an embodiment of the present invention.

[0043] Fig.16 This is a schematic diagram of the fiber layout model of the hedgehog-like thorn shell of a lightweight impact-resistant composite material plate with a hedgehog-like thorn microstructure according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention provides a lightweight impact-resistant composite material plate with a microstructure imitating hedgehog spines and a preparation method thereof. The present invention belongs to the technical field of low-speed impact resistance of sandwich composite material plates, and specifically relates to a bionic impact-resistant protective structure based on the energy dispersion effect of a porous structure and a preparation method thereof. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0046] The emergence of bionics has opened up ideas for the present invention. Billions of years of evolution of organisms have formed complex and outstanding structures and properties: although biological materials are assembled under mild conditions (water, room temperature), limiting the biological components, their performance is not as fragile as expected: the performance of mussels and deer antlers far exceeds the performance of artificial materials composed of their components alone. Therefore, a comprehensive analysis of the structure, formation conditions, failure mechanism and mechanical properties of organisms has a far-reaching impact on the development and manufacture of bionic structural engineering materials. When hedgehogs are avoiding natural enemies and predators, they are often thrown down from low altitudes or curled up and rolled by external forces, but the hedgehog spines on the outside of the body play an impact protection role and the sandwich porous structure are intact, so that the internal body is not damaged. Therefore, the hedgehog spines can be used as a low-speed impact resistance model, and a lightweight impact-resistant composite material board with a microstructure imitating hedgehog spines can be designed and prepared to solve the problem of debonding and fracture damage of the interface between the panel and the core due to stress concentration when the sandwich panel is subjected to a low-speed impact.

[0047] The present invention aims to solve the problem of debonding and fracture at the interface between the panel and the core when subjected to low-speed impact in traditional sandwich panel structures. The fundamental reason for this problem is that stress concentration occurs at the interface due to the sudden change in the properties of heterogeneous materials when subjected to force. The large stress here will cause the material to crack first and cause the overall structure to fail prematurely. Therefore, the key to solving this problem is to alleviate the local stress concentration phenomenon of the overall structure.

[0048] like Figure 1 As shown, an embodiment of the present invention provides a lightweight impact-resistant composite material plate imitating hedgehog thorn microstructure. The composite material described in the embodiment of the present invention is a hedgehog thorn hard thin shell-flexible porous sandwich composite material, such as Figure 1 As shown, the overall structure of the lightweight impact-resistant composite material plate imitating the hedgehog thorn microstructure includes:

[0049] A porous structure core layer composed of transverse reinforcement ribs 1 and longitudinal reinforcement ribs 3;

[0050] An upper panel 4, wherein the upper panel 4 is arranged on the upper surface of the porous structure core layer;

[0051] A lower panel 2, the lower panel 2 being arranged on the lower surface of the porous structure core layer;

[0052] The porous structure core layer is made of short fiber epoxy resin material, the upper panel 4 and the lower panel 2 are made of mixed fiber epoxy resin material with variable modulus and variable density, and the upper panel 4 and the lower panel 2 are arranged by fiber ply;

[0053] The overall structure of the lightweight impact-resistant composite material plate with a microstructure imitating hedgehog spines is prepared by 3D printing and integrated molding to form a bionic porous structure composite sandwich plate. Compared with the traditional sandwich plate structure, the present invention further improves its specific stiffness and specific strength, alleviates the local stress concentration caused by the sudden change of the properties of heterogeneous materials, and solves the problem of debonding and fracture of the interface between the upper and lower panels and the core layer due to stress concentration, and premature failure.

[0054] In the embodiment of the present invention, through the characterization of the macroscopic structure of the hedgehog spines, it is found that the hedgehog spines are a hard thin shell-flexible porous core layer structure. Based on this idea, the sandwich layer of the present invention, i.e., the porous structure core layer, is provided. Figure 3 As shown, the hedgehog thorn core layer is composed of a porous structure of longitudinal and transverse reinforcement ribs, the radial thickness t of the thin-wall shell, the radial length R1 of the longitudinal reinforcement rib, and the length R2 of the central merging area of ​​the transverse reinforcement rib are regularly 1:4:8. This biological structure design makes the whole have high specific strength and high specific stiffness, so by imitating the macroscopic structure of the hedgehog thorn, the porous structure core layer is set to adopt a hedgehog-like hard thin shell-flexible porous core layer structure; the porous structure core layer is composed of transverse reinforcement ribs and longitudinal reinforcement ribs to form a sandwich layer, and the thickness ratio of the upper panel, the porous structure core layer and the lower panel is 1:16:1; the internal structure of the hedgehog thorn is measured and statistically obtained, and it is obtained that the ratio of the transverse reinforcement rib thickness and the transverse reinforcement rib spacing of the porous structure core layer prepared by the present invention to the thickness of the upper and lower panels is 1:7.54:5.8, and the porous structure core layer is formed by 3D printing of a fiber hybrid composite material, and its specific modulus is close to that of E glass fiber, which is about 0.29*10 5 MPa.

[0055] In the embodiment of the present invention, Figure 6 and Figure 7 As shown, Figure 6 This is an electron microscope image of the hedgehog spines. Figure 7 The electron microscope image of the outer shell of the hedgehog spines is further enlarged. Through the characterization of the micro-nanostructure of the outer shell of the hedgehog spines, it is found that it is composed of hard and dense fiber layers arranged in a staggered manner at 0°, ±45°, and 90°. The fiber layers are arranged more and more loosely from the outside to the inside, and the modulus of the fiber layers gradually decreases. According to the microscopic fiber arrangement of the organism, the present invention prepares a new type of variable modulus and variable density mixed fiber ply, and further prepares it into the upper panel and the lower panel. Fig.16 As shown, the upper panel and the lower panel each include a first layer S1, a second layer S2, and a third layer S3 from the outside to the inside, and the first layer S1 has a specific modulus of (2.0-2.34)*10 5 MPa high modulus carbon fiber is staggered at 0°, ±45°, and 90°. The second layer S2 is composed of a specific modulus of 0.58*10 5MPa K-49Ⅳ aramid fiber is staggered at 0°, ±45°, and 90°. The third layer S3 is composed of a specific modulus of 0.29*10 5 MPa E glass fibers are staggered at 0°, ±45°, and 90°, and the fiber arrangement density of the first layer S1, the second layer S2, and the third layer S3 from the outside to the inside shows a decreasing trend. The upper panel, the lower panel, and the porous structure core layer sandwiched in the middle are prepared by 3D printing.

[0056] It can be seen from the above that the present invention analyzes the low-speed impact simulation results of the hedgehog-like thorn structure model and the comparison structure model, and it can be proved that the existence of the longitudinal and transverse reinforcement ribs inside the hedgehog thorn can relieve and disperse the local internal stress. By analyzing the low-speed impact simulation results of the hedgehog-like thorn internal structure + shell fiber laying structure model and the single hedgehog-like thorn internal structure model, the shell fiber laying structure can further enhance the local stress dispersion effect and improve the impact resistance. Therefore, the upper panel, the lower panel and the transverse and longitudinal reinforcement rib porous structure core layer prepared by the mixed fiber laying layer of the present invention are arranged and integrally printed and formed, which also has the effect of relieving and dispersing local stress concentration under low-speed impact loads.

[0057] In a further embodiment, the hedgehog spine is a porous structure in biological classification, and its entirety is composed entirely of fiber layers. Figure 6 This is the change of elastic modulus measured by nanoindentation from the outside to the inside of the hedgehog thorn shell. Figure 7 The three-dimensional model diagram of the hedgehog spine structure and the contrast structure is shown in Figure 2. Figure 6 , 7 As shown in the figure, the hedgehog spines are composed of hard and dense interlaced fiber layers, which are arranged more and more loosely from the outside to the inside, and the fiber diameter increases. Figure 8 , the shell is subjected to nano-indentation test, and the elastic modulus of the shell decreases from the outside to the inside. This fiber arrangement method can make the hedgehog shell have high specific strength. After microcracks occur, the changing fiber arrangement direction causes the cracks to deflect, and crack expansion places produce cross-linking, which increases the fracture toughness. In summary, the shell fiber arrangement method can make the overall structure absorb more energy when subjected to stress. Therefore, the upper panel and the lower panel provided by the present invention are composite panels that imitate the hedgehog shell fiber arrangement method to improve the specific strength and fracture toughness of the overall structure.

[0058] like Fig.16, which is a fiber layout model diagram of the upper panel and the lower panel of the hedgehog thorn shell. From the outside to the inside, the fiber density gradually decreases and the fiber diameter gradually increases. This biological feature is realized through the fiber mixing theory, that is, from the outside to the inside, fibers with different diameters and different elastic moduli are used for density gradient laying to achieve the laying design of the hedgehog thorn microfiber structure and the replication of the excellent biological performance, so as to prepare a fiber composite material panel with both high specific strength and fracture toughness.

[0059] In one embodiment, if Figure 3 and Figure 5 As shown, the core layer of the hedgehog spine has a porous structure of the bracket - internal longitudinal and transverse reinforcement ribs, the transverse reinforcement ribs span the entire cross section, every three merged in the center, the longitudinal reinforcement ribs span the entire longitudinal direction, extending from the outer shell to the convergence of the transverse reinforcement ribs. Therefore, if you observe the longitudinal section biased to the center, the cross section presents a relatively uniform grid structure, such as Figure 4 In order to verify the impact of the internal reinforcement ribs of the hedgehog thorn on the impact resistance, the present invention sets up a three-dimensional model of the hedgehog thorn structure and a comparison structure, as shown in FIG. Fig. 9 The three-dimensional model diagram of the lightweight impact-resistant composite material plate imitating the microstructure of the hedgehog spines of the present invention and the comparative structure is shown, and the low-speed impact simulation is performed using ANSYS, such as Fig.10 , 11 It can be seen that the stress contour lines and isosurfaces of the two models are concentrated at the tip, indicating that there is stress concentration at the tip, but the contour lines and isosurfaces at the tip of the comparison structure are denser, indicating that the stress dispersion effect of the hedgehog thorn structure is stronger than that of the comparison structure.

[0060] Further, the stress results of the two are analyzed, such as Fig.12 As shown, Fig.12 Comparing the stress comparison diagram of the low-speed impact simulation of the structure model and the hedgehog-like structure model, it can be seen that the maximum stress of the structureless model is always higher than that of the hedgehog-like structure model, indicating that the bionic structure can better relieve local internal stress. The definition of the specific deformation set by the present invention is the ratio of the actual deformation amount to the mass, such as Fig.13 As shown, Fig.13 The comparison diagram of the specific deformation of the comparison structure model and the hedgehog thorn structure model under low-speed impact simulation shows that the specific deformation of the comparison structure model is always higher than that of the bionic structure model, indicating that under the same impact load, the bionic structure can better resist the impact. In summary, it can be proved that the existence of the longitudinal and transverse reinforcement ribs inside the hedgehog thorn can relieve and disperse the local internal stress and improve the impact resistance.

[0061] In one embodiment, if Fig.16As shown, the upper panel and the lower panel of the embodiment of the present invention are composed of a first layer S1, a second layer S2, and a third layer S3, which is a fiber laying model imitating the hedgehog thorn shell, and each of the first layer S1, the second layer S2, and the third layer S3 is composed of a plurality of variable-angle fiber layers, and a single fiber layer in the variable-angle fiber layer contains a plurality of fibers, and the plurality of fibers are laid straight and parallel in the same direction, and the single fiber layers are connected by resin curing, and the density of the first layer S1, the second layer S2, and the third layer S3 is controlled by the printed fiber content, and the fiber content gradually decreases from the outside to the inside, thereby realizing the bionic application and performance replication of biological to engineering materials.

[0062] Furthermore, the first layer S1 has a specific modulus of (2.0-2.34)*10 5 MPa high modulus carbon fiber is staggered at 0°, ±45°, and 90°; the second layer S2 is composed of a specific modulus of 0.58*10 5 MPa K-49Ⅳ aramid fiber is staggered at 0°, ±45°, and 90°; the third layer S3 is composed of a specific modulus of 0.29*10 5 MPa E glass fibers are staggered at 0°, ±45°, and 90°, and the fiber arrangement density of the first layer S1, the second layer S2, and the third layer S3 decreases from the outside to the inside. The upper panel, the lower panel, and the porous structure core layer sandwich layer are prepared by 3D printing.

[0063] Based on the above embodiment, the embodiment of the present invention further provides a method for preparing a lightweight impact-resistant composite material plate with a microstructure imitating hedgehog spines. The preparation method of the present invention is to integrally form the upper panel, the lower panel and the porous structure core layer through a fiber 3D printing integral molding process; the preparation method specifically comprises the following steps:

[0064] The first step: pre-inputting a three-dimensional model of a lightweight impact-resistant composite material plate with a microstructure imitating hedgehog spines on a fiber 3D printer, and pre-setting the materials of the upper panel, the core layer, and the lower panel;

[0065] Step 2: Prepare the lower panel by printing layer by layer through a fiber 3D printer: first replace the printing material of the 3D printer with resin-based carbon fiber to print the first layer S1 of the lower panel, then replace the printing material of the 3D printer with resin-based aramid fiber to print the second layer S2 of the lower panel, and then replace the printing material of the 3D printer with resin-based E glass fiber to print the third layer S3 of the lower panel, so as to prepare a new type of composite material board with variable modulus and variable density imitating the hedgehog thorn shell fiber layout method, and form the preparation of the upper panel;

[0066] Step 3: Replace the printing material of the 3D printer with epoxy resin mixed with short fiber material, use short fiber epoxy resin material to prepare the porous structure core layer through a fiber 3D printer;

[0067] Step 4: Prepare to prepare the upper panel, print layer by layer through a fiber 3D printer, first replace the printing material of the 3D printer with resin-based carbon fiber to print the first layer S1 of the upper panel, then replace the printing material of the 3D printer with resin-based aramid fiber to print the second layer S2 of the upper panel, and then replace the printing material of the 3D printer with resin-based E glass fiber to print the third layer S3 of the upper panel, so as to prepare a new type of composite material board with variable modulus and variable density imitating hedgehog thorn shell fiber layout on the prepared porous structure core layer to prepare the upper panel.

[0068] That is, the present invention prepares the entire bionic model by 3D printing, and during printing, starts from the lower panel and prints upwards, after the lower panel is printed, replaces the material to print the porous structure core layer on the lower panel, and then replaces the material again to print the upper panel. The upper panel, the lower panel and the porous structure core layer sandwiched in the middle are prepared by 3D printing as a whole.

[0069] In summary, the present invention provides a lightweight impact-resistant composite material plate with a hedgehog-like microstructure and a preparation method thereof. The present invention provides a lightweight impact-resistant composite material plate with a hedgehog-like microstructure and a preparation method thereof, provides a design and integrated printing molding technology of a hybrid fiber ply panel and a porous core layer with transverse and longitudinal reinforcement ribs, and through a bionic porous structure and a unique hybrid fiber bundle arrangement method, the sandwich fiber composite material plate structure has high specific strength and high specific stiffness. When subjected to a low-speed impact, the debonding and fracture damage of the interface between the panel and the core due to stress concentration can be avoided. This new structural composite material can meet the higher requirements of key components such as floors, side wall panels, inner roof panels, partition panels, door panels of inner and outer doors in the passenger compartment interior structure of Chinese rail passenger cars: it has excellent mechanical properties of light weight, high strength, high fracture toughness, and resistance to low-speed impact.

[0070] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, 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 lightweight impact-resistant composite material plate with a hedgehog-like microstructure, characterized in that: The overall structure of the lightweight impact-resistant composite material plate imitating the hedgehog spine microstructure includes: A porous core layer composed of transverse and longitudinal reinforcement ribs; An upper panel, the upper panel being arranged on the upper surface of the porous structure core layer; A lower panel, the lower panel being arranged on the lower surface of the porous structure core layer; The porous core layer adopts a hedgehog-like hard thin shell-flexible porous core layer structure; the upper panel and the lower panel adopt a composite material plate with a hedgehog-like outer shell fiber laying method, and the upper panel and the lower panel adopt a fiber laying arrangement; The overall structure of the lightweight impact-resistant composite material plate imitating the hedgehog spine microstructure is prepared by 3D printing and integrated molding to form a bionic porous structure composite material sandwich plate; The porous structure core layer is made of short fiber epoxy resin material, and the upper panel and the lower panel are made of mixed fiber epoxy resin material plates with variable modulus and variable density; The ratio of the thickness of the transverse reinforcing ribs of the porous core layer, the spacing between the transverse reinforcing ribs and the thickness of the upper and lower panels is 1:7.54:5.8; The upper panel and the lower panel are divided into a first layer, a second layer and a third layer from the outside to the inside, and are a fiber laying model imitating the outer shell of a hedgehog; The first layer, the second layer and the third layer are each composed of multiple variable angle fiber layers, wherein a single fiber layer in the variable angle fiber layer contains multiple fibers, the multiple fibers are laid parallel and straight in the same direction, and the single fiber layers are connected by resin curing; The first layer is composed of high modulus carbon fibers with a specific modulus of (2.0-2.34)*105MPa, which are staggered at 0°, ±45°, and 90°; the second layer is composed of K-49Ⅳ aramid fibers with a specific modulus of 0.58*105MPa, which are staggered at 0°, ±45°, and 90°; the third layer is composed of E glass fibers with a specific modulus of 0.29*105MPa, which are staggered at 0°, ±45°, and 90°; and the fiber arrangement density of the first layer, the second layer, and the third layer from the outside to the inside is in a decreasing trend; The thickness ratio of the upper panel, the porous structure core layer and the lower panel is 1:16:1; The transverse stiffeners span the entire cross section, with every three merging in the center, and the longitudinal stiffeners span the entire longitudinal direction, extending from the shell to the point where the transverse stiffeners converge.

2. The lightweight impact-resistant composite material plate with a hedgehog-like microstructure according to claim 1, characterized in that: The porous structure core layer is formed by 3D printing of a fiber hybrid composite material, and the specific modulus of the porous structure core layer is 0.29*105MPa.

3. A method for preparing a lightweight impact-resistant composite material plate with a hedgehog-like microstructure as described in any one of claims 1 to 2, characterized in that: Includes steps: A: pre-inputting a three-dimensional model of a lightweight impact-resistant composite material plate with a microstructure imitating hedgehog spines on a fiber 3D printer, and pre-setting the materials of the upper panel, the core layer and the lower panel; B: Prepare the lower panel by printing layer by layer through a fiber 3D printer: first replace the printing material of the 3D printer with resin-based carbon fiber to print the first layer S1 of the lower panel, then replace the printing material of the 3D printer with resin-based aramid fiber to print the second layer S2 of the lower panel, and then replace the printing material of the 3D printer with resin-based E-glass fiber to print the third layer S3 of the lower panel, so as to prepare a composite material plate with variable modulus and variable density and imitating the hedgehog thorn shell fiber layout method, and form the lower panel; C: replacing the printing material of the 3D printer with epoxy resin mixed with short fiber material, using short fiber epoxy resin material to prepare the porous structure core layer by a fiber 3D printer; D: Prepare to prepare the upper panel, print it layer by layer through a fiber 3D printer, first replace the printing material of the 3D printer with resin-based E glass fiber to print the third layer S3 of the upper panel, then replace the printing material of the 3D printer with resin-based aramid fiber to print the second layer S2 of the upper panel, and then replace the printing material of the 3D printer with resin-based carbon fiber to print the first layer S1 of the upper panel, so as to prepare a composite material board with variable modulus and variable density and a hedgehog thorn shell fiber layout on the prepared porous structure core layer to prepare the upper panel.

4. The preparation method according to claim 3, characterized in that: The upper panel and the lower panel are prepared as a first layer, a second layer, and a third layer from the outside to the inside, which is a fiber laying model imitating the outer shell of a hedgehog thorn. The density of the first layer, the second layer, and the third layer is controlled by the printed fiber content, and the fiber content gradually decreases from the outside to the inside; the upper panel, the lower panel, and the porous structure core layer sandwiched in the middle are prepared by 3D printing as an integral part.

Images