A full composite n-type porous corrugated structure and a preparation method thereof

Abstract

The application discloses a kind of full composite N type porous corrugated structure and preparation method, belong to full composite N type porous corrugated structure design and preparation technical field, the structure of the present application includes: upper and lower fixed baffle, the transverse two sides of the upper and lower fixed baffle are T-shaped pressing block, the longitudinal two sides of upper and lower fixed baffle are side baffle;The space formed by upper and lower fixed baffle, side baffle, T-shaped pressing block is full composite N type porous corrugated structure core, and the full composite N type porous corrugated structure core constitutes and includes several trapezoidal moulds, cuboid mould and composite material prepreg.The application proposes a kind of full composite N type porous corrugated structure based on the folding forming idea, realizes one forming in combination with forming process design, and structure preparation process is greatly reduced, and structure performance is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of design and preparation technology of all-composite N-type porous corrugated structures, specifically to a novel design and molding method for all-composite N-type porous corrugated structures. Background Technology

[0002] Ultralight porous materials are a new type of engineering material possessing both functional and structural properties. Represented by disordered microstructures like foam and ordered microstructures like lattice structures, they exhibit excellent characteristics such as lightweight, high energy absorption efficiency, heat dissipation, and vibration and noise reduction. Among these, ordered, periodic lattice sandwich structures not only maintain the high porosity of porous materials but also possess advantages such as high specific strength, high specific stiffness, multi-functionality in load-bearing and protection, and designability. They can effectively address the urgent needs of the defense industry for lightweight, low-energy-consumption, and high-performance structures. Porous corrugated structures have become a research hotspot in the field of structural lightweighting. Due to their ease of molding and multi-functionality, porous corrugated structures have wide applications in the aerospace field. However, when subjected to out-of-plane compressive loads, corrugated structures exhibit low buckling strength, leading to buckling failure. Therefore, improving the load-bearing performance of corrugated structures is a crucial research topic.

[0003] In recent years, with the development of composite material preparation technology, the preparation of novel lattice structures using fiber-reinforced composite materials has gradually emerged. From a structural perspective, porous composite structures possess mechanical properties comparable to traditional porous metal structures, and also offer advantages such as high specific strength and high specific stiffness. For multi-level composite structures, a common preparation method is multiple curing, where each component is prepared and then assembled using adhesive bonding. For all-composite N-type corrugated cores, secondary curing is required: the pre-formed I-type corrugations are embedded into a V-type corrugated structure through secondary adhesive curing to form N-type corrugations. Secondary curing presents problems such as residual thermal deformation and complex processes. For example, the bonding platforms of the V-type corrugated structure and the I-type structure cannot completely overlap, causing the I-type structure to deflect during secondary curing, thus affecting structural performance. Summary of the Invention

[0004] To address the problems existing in the aforementioned technologies, a novel all-composite N-type porous corrugated structure needs to be designed. This structure should improve the load-bearing capacity of the porous corrugated structure while retaining the porous characteristics of the core, possessing multifunctional properties such as sound insulation and heat dissipation. Based on the designed structure, a new, simple, and efficient preparation mold and corresponding processing technology are invented. This invention proposes an all-composite N-type porous corrugated structure based on origami molding principles. Combined with molding process design, it achieves one-step molding, significantly reducing the structure preparation process and greatly improving structural performance.

[0005] This invention is implemented as follows:

[0006] A fully composite material N-type porous corrugated structure, characterized in that the structure includes: upper and lower fixed baffles, the upper and lower fixed baffles having T-shaped pressure blocks on both sides in the lateral direction and side baffles on both sides in the longitudinal direction;

[0007] The space formed by the upper and lower fixed baffles, side baffles, and T-shaped pressure blocks contains a corrugated core of all-composite materials. The corrugated core of all-composite materials includes several trapezoidal molds, several cuboid molds, and composite material prepreg. One end of the composite material prepreg is placed on the cuboid mold, with the starting end of the composite material prepreg flush with the cuboid mold to ensure the correct fiber orientation. The trapezoidal mold is placed on the composite material prepreg, with the right-angled edge of the trapezoidal mold fitting against the cuboid mold and the bottom facing upwards, ensuring that the composite material prepreg fits the mold. The composite material prepreg is folded along the top bottom and fitted with the oblique edge. Another trapezoidal mold is added, with the oblique edges of the two trapezoidal molds fitting against each other. The top bottom of the newly added trapezoidal mold faces upwards, and the composite material prepreg is folded along the top bottom and fitted with the right-angled edge.

[0008] Then, the prepreg is placed in a cuboid mold, and the composite material prepreg is first folded along the short side of the mold and attached to the long side; then, a trapezoidal mold is placed in, with the right-angled side attached to the cuboid mold and the top bottom facing upwards; the prepreg is then folded and attached to the hypotenuse; then, a trapezoidal mold is placed in, with the bottom edge facing upwards, and the hypotenuses of the two trapezoidal molds are attached to each other, and the prepreg is folded along the top bottom and attached to the right-angled side; then, a cuboid mold is placed in, and the prepreg is folded along the short side of the mold and attached to the long side, forming one unit cell of the all-composite N-type porous corrugated structure core; multiple unit cells are repeated to form the all-composite N-type porous corrugated structure core.

[0009] Furthermore, the side baffle is fixed by side baffle bolts; the upper and lower fixed baffles are fixed by integral fixing bolts and integral fixing nuts; the trapezoidal mold and the cuboid mold are fixed by fixing screws and fixing nuts at both ends.

[0010] A method for preparing an all-composite N-type porous corrugated structure, characterized in that the method comprises:

[0011] Step 1: Pretreatment of composite prepreg. First, use a prepreg cutter to cut the composite prepreg.

[0012] Step 2: Laying up the composite prepreg;

[0013] Step 3: Assembly of the all-composite N-type porous corrugated structure core;

[0014] First, place the rectangular mold on the two fixing screws, and fix the lower end of the fixing screws with fixing nuts to prevent the mold from slipping off;

[0015] Then, place one end of the laid-up composite prepreg onto the cuboid mold, ensuring the starting end of the composite prepreg is flush with the cuboid mold to guarantee the correct fiber orientation; place the trapezoidal mold on the composite prepreg, with the right-angled edge of the trapezoidal mold fitting against the cuboid mold and the bottom facing upwards, ensuring the composite prepreg fits the mold; fold the composite prepreg along the top bottom and fit it against the beveled edge, then add another trapezoidal mold, with the beveled edges of the two trapezoidal molds fitting against each other, the top bottom of the newly added trapezoidal mold facing upwards, and fold the composite prepreg along the top bottom and fit it against the right-angled edge;

[0016] Then, the composite prepreg is placed in a cuboid mold, and the prepreg is first folded along the short side of the mold and attached to the long side; then, a trapezoidal mold is placed in, with the right-angled side attached to the cuboid mold and the top bottom facing upwards; the prepreg is then folded along the top bottom and attached to the hypotenuse; then, a trapezoidal mold is placed in, with the bottom edge facing upwards, and the hypotenuses of the two trapezoidal molds are attached to each other, and the prepreg is folded along the top bottom and attached to the right-angled side; then, a cuboid mold is placed in, and the prepreg is folded along the short side of the mold and attached to the long side, forming one unit cell of the all-composite N-type porous corrugated structure core; this process is repeated for multiple unit cells;

[0017] Step 4: Curing of the all-composite N-type porous corrugated core;

[0018] Step 5: Preparation of composite material panels. The composite material panels are formed using an autoclave curing process. The curing method is the same as that of the N-type porous corrugated structure core of the all-composite material, and is the same as in Step 4.

[0019] Step Six: Assembly of the all-composite N-type porous corrugated structure.

[0020] Furthermore, in step one, unidirectional bitumen-based glass fiber prepreg is used, and the length of the prepreg after cutting is 650mm long and 250mm wide.

[0021] Furthermore, in step two, unidirectional composite prepreg is used for material layup; the fiber direction is set as 0° and the fiber perpendicular direction is set as 90°; the fiber bearing direction is used as the main direction and the constraint direction is used as the auxiliary direction. At the same time, the layup needs to meet the requirement of symmetrical layup to ensure that the structure does not deviate after curing; the layup is carried out using a 0° / 90° / 0° layup method; during layup, a heating table is used to heat the prepreg to 50°C first, so that the resin on the surface of the prepreg is initially melted, and then the prepreg is laid up.

[0022] Furthermore, in step three, the mold placement sequence is as follows: cuboid mold - trapezoidal mold - trapezoidal mold - cuboid mold - trapezoidal mold - trapezoidal mold; the other end of the mold after laying also needs to be fixed with screws and nuts to prevent the laid mold from moving; the fixed all-composite N-type porous corrugated core is placed in the upper and lower fixed baffles, one end is fixed and constrained by the side baffle, and the other end is constrained by the T-shaped pressure block, which is used to apply curing pressure during the curing process; the excess fixing screws are put into the through holes of the T-shaped pressure block;

[0023] Finally, fixing bolts and overall fixing nuts are inserted into the four through holes of the upper and lower fixing baffles to constrain the entire structure and facilitate transportation; the number of independent core layer inner molds can be adjusted according to structural size requirements to reduce the structural performance degradation caused by subsequent dimensional processing.

[0024] Furthermore, the all-composite N-type porous corrugated structure core has one unit cell, and the all-composite N-type porous corrugated structure is configured with eight unit cells.

[0025] Furthermore, in step four, the assembled all-composite N-type porous corrugated structure core is cured using an autoclave curing process. The specific operation procedure is as follows:

[0026] Wrap a breathable felt around the assembled core mold, then seal it with a vacuum bag, placing a vacuum valve on the bag. Place the entire assembly into an autoclave, connecting the vacuum valve to the autoclave's evacuation pipe. The curing parameters for the all-composite N-type porous corrugated core are as follows: The autoclave temperature profile is set as follows: First, the temperature is increased by 5°C per minute to 80°C. During this process, the autoclave is only evacuated without additional pressurization. After reaching 80°C, the temperature is maintained for 30 minutes, with an internal pressure of 0.1 MPa. After the process, the temperature is increased at the same rate to 130°C, maintaining an internal pressure of 0.1 MPa. After reaching 130°C, the temperature is maintained for 90 minutes, with an internal pressure of 0.3 MPa. After the process, the autoclave is cooled at a rate of 10°C per minute while maintaining an internal pressure of 0.3 MPa. Once the sample temperature drops to 60°C, the pressure inside the autoclave is released, and the cured core is removed. The mold is then removed to obtain the all-composite N-type porous corrugated core.

[0027] Furthermore, in step six, the adhesive film is pasted onto the bonding platform of the composite material N-type porous corrugated core, and then vacuum-assisted molding technology is used: first, the bonded composite material N-type corrugated structure is placed in the same manner as peelable fabric, breathable felt, and vacuum bag; then it is placed in a temperature chamber, and an external vacuum pump is used to evacuate the air to ensure that the sample is in a vacuum throughout the curing process; the temperature parameters are as follows: first, the temperature is increased at a rate of 3℃ / minute, and after reaching 80℃, it is held for 30 minutes, then the temperature is increased at a rate of 5℃ / minute to 130℃, and held at this temperature for 90 minutes, then the temperature chamber is closed, and after the temperature chamber cools down to 60℃, the temperature chamber is opened and the vacuum pump is turned off, and the sample is taken out.

[0028] The advantages of this invention compared to the prior art are as follows:

[0029] This invention proposes a novel all-composite N-type porous corrugated structure to address the weakness of traditional corrugated structures in out-of-plane compression resistance. A high-performance and reliable method for fabricating this N-type corrugated structure is presented, which involves hot-pressing a unidirectional composite prepreg with multiple independent core layer molds to improve the residual thermal deformation and low molding quality issues present in the fabrication process. Furthermore, the number of independent core layer molds can be adjusted according to structural dimensional requirements, reducing the structural performance degradation caused by subsequent dimensional processing. This novel all-composite N-type porous corrugated structure exhibits high out-of-plane compression modulus and strength, strong dimensional design flexibility, high molding quality, and a simple and feasible fabrication process, making it suitable for industrial production and application.

[0030] Traditional thermosetting molds for corrugated structures can only be used to prepare simple corrugated composite material structures. When there are two or more different structures in the smallest unit cell of the core layer, traditional molds cannot be successfully used. In the example of this invention, a single smallest unit cell contains two different structures, namely an I-type corrugated structure and a traditional V-type corrugated structure, so traditional molds are no longer applicable.

[0031] This invention innovatively employs a completely separable mold, building upon traditional curing molds. By disassembling the overall mold into independent smaller molds, the assembly of the prepreg and mold is changed from the original method of pressing the prepreg onto the mold to a method of bending and bonding the prepreg to the mold. This achieves mold-based production of complex structures and simultaneously solves the problem of bonding between the mold and the prepreg. Under constant density, the out-of-plane compressive stiffness of the all-composite N-type porous corrugated structure is increased by more than 30% compared to the traditional corrugated structure. This demonstrates that this invention can obtain a corrugated structure with better performance through a simple manufacturing process, indicating broad prospects for future applications. Attached Figure Description

[0032] Figure 1 A schematic diagram of the origami forming process for an all-composite N-type corrugated structure;

[0033] Figure 2 An example diagram of the fabrication of an all-composite N-type corrugated structure;

[0034] Figure 3 Schematic diagram of the laying of the all-composite N-type corrugated structure core;

[0035] Figure 4 A schematic diagram of the completed N-type porous corrugated structure of the all-composite material;

[0036] Figure 5 This is a comparison diagram of the out-of-plane compressive strength of the embodiment and the conventional corrugated structure;

[0037] Among them, 1-upper and lower fixed baffles, 2-overall fixed bolts, 3-side baffle bolts, 4-side baffles, 5-T-shaped pressure block, 6-overall fixed nuts, 7-composite prepreg, 8-trapezoidal mold, 9-cubic mold, 10-fixing screw, 11-fixing nut. Detailed Implementation

[0038] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples provide a more detailed description of the invention. It should be noted that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0039] Figure 1 This is a schematic diagram illustrating the design process and structure of the present invention. The invention draws inspiration from origami structure forming concepts, simulating the fabrication process of a composite material corrugated structure through the process of forming the desired structure using origami.

[0040] Structure 1 is the initial corrugated structure, which can be seen as formed by folding paper once. For all-composite corrugated structures, the face sheet and core are generally connected by an adhesive process, so an adhesive platform is needed between the face sheet and the core. For this reason, a small platform is added at the fold of the paper to form Structure 2, which is a common composite corrugated structure.

[0041] For structure 2, a common approach to introduce additional support structures is to re-fabricate a composite material type I corrugated structure and bond it to the traditional composite material corrugated structure. This method requires secondary curing of the core, and the prepared composite material structure is difficult to process, resulting in low compatibility with different structures.

[0042] Based on the above factors, this invention employs a folding method to add a Type I corrugated structure to the composite material. This requires folding structure 2 again, extending the bonding platform, and then folding the platform in half so that the height after folding matches the corrugated structure, resulting in structure 3. In the folding diagram, solid red lines represent outward creases, and dashed red lines represent inward creases. Structure 3 suffers from the same problem as structure 1: the lack of a bonding platform. Therefore, structure 3 needs optimization by adding a bonding platform to each area requiring bonding to the panel. The final optimized structure is structure 4.

[0043] like Figures 2-4 As shown in this embodiment, a method for preparing an all-composite N-type porous corrugated structure is described, using a unidirectional bitumen-based glass fiber composite prepreg. The preparation method includes the following steps:

[0044] Step 1: Pretreatment of composite prepreg 7. First, the composite prepreg is cut using a prepreg cutting machine. In this embodiment, it is a unidirectional bitumen-based glass fiber prepreg. The length of the prepreg after cutting is 650mm long and 250mm wide.

[0045] Step Two: Composite Prepreg Layup. This embodiment uses unidirectional composite prepreg, so material layup is required. In this embodiment, the fiber direction is defined as 0°, and the fiber perpendicular direction is defined as 90°. The fiber bearing direction is used as the primary direction, and the constraint direction is used as the secondary direction. Simultaneously, the layup must be symmetrical to ensure that the cured structure does not deviate. Based on these factors, this invention uses a 0° / 90° / 0° layup method. During layup, a heating table is used to heat the prepreg to 50°C first, causing the resin on the prepreg surface to initially melt, and then the prepreg is laid up.

[0046] Step 3: Assembly of the all-composite N-type porous corrugated core. Figure 3To assemble the fully composite N-type porous corrugated core, first, place a cuboid mold 9 on two fixing screws 10, securing the lower ends of the screws with nuts to prevent the mold from slipping. Then, place one end of the prepreg laid up onto the cuboid mold 9, ensuring the starting end of the prepreg is flush with the mold and the fiber orientation is correct. Place a trapezoidal mold 8 on the prepreg, with the right-angled edge of the trapezoidal mold 8 fitting against the cuboid mold 9, bottom facing up, ensuring the prepreg fits snugly against the mold. Fold the prepreg along the top bottom and fit it against the beveled edge. Add another trapezoidal mold 8, with the beveled edges of the two trapezoidal molds 8 fitting together, top facing up. Fold the prepreg along the top bottom and fit it against the right-angled edge. Then, place the cuboid mold 9, first folding the prepreg along the short side and fitting it against the long side. Place the trapezoidal mold 8, with the right-angled edge fitting against the cuboid mold 9, top facing up. The prepreg is folded and its beveled edges are attached. Trapezoidal mold 8 is placed in, bottom edge facing upwards, with the beveled edges of the two trapezoidal molds 8 attached together. The prepreg is folded along the top bottom and attached to the right-angled edge. Then, cuboid mold 9 is placed in, with the prepreg folded along the short side of the mold and attached to the long side, forming one unit cell of the all-composite N-type porous corrugated structure core. The mold placement sequence is: cuboid mold 9 - trapezoidal mold 8 - trapezoidal mold 8 - cuboid mold 9 - trapezoidal mold 8 - trapezoidal mold 8. This example uses 8 unit cells. The other end of the mold after laying also needs to be secured with nuts to prevent movement. The fixed core mold is placed in the upper and lower baffles, with one end secured by a side baffle. The other end is secured with a T-shaped pressure block to apply curing pressure during the curing process. Excess screws can be inserted into the through holes of the T-shaped pressure block. Finally, screws and nuts are inserted into the four through holes of the upper and lower baffles to secure the entire structure and facilitate handling. In particular, the number of independent core layer inner molds can be adjusted according to structural size requirements to reduce the structural performance degradation caused by subsequent dimensional processing.

[0047] Step Four: Curing of the All-Composite N-Type Porous Corrugated Core. The assembled all-composite N-type porous corrugated core is cured using an autoclave curing process. The specific operation procedure is as follows: Wrap a breathable felt around the assembled core mold, then seal it with a vacuum bag, placing a vacuum valve on the sealed bag. Place the entire assembly into the autoclave, connecting the vacuum valve to the autoclave's evacuation pipe. The curing parameters for the all-composite N-type porous corrugated core are as follows: The autoclave temperature profile is set as follows: First, the temperature is increased by 5°C per minute to 80°C. During this process, the autoclave is only evacuated without additional pressurization. After reaching 80°C, the temperature is maintained for 30 minutes, with the internal pressure set to 0.1 MPa. After the process, the temperature is increased at the same rate to 130°C, maintaining a pressure of 0.1 MPa within the autoclave. After reaching 130°C, the temperature is maintained for 90 minutes, with the internal pressure set to 0.3 MPa. After the process is completed, the autoclave is kept at a pressure of 0.3 MPa for cooling at a rate of 10°C per minute. Once the sample temperature drops to 60°C, the pressure inside the autoclave is released, and the cured core is removed. The mold is then removed to obtain a fully composite N-type porous corrugated core.

[0048] Step 5: Composite material panel preparation. The composite material panel is formed using an autoclave curing process. Its curing process is consistent with that of the all-composite N-type porous corrugated structure core.

[0049] Step Six: Assembly of the all-composite N-type porous corrugated structure. Adhesive film is pasted onto the bonding platform of the composite N-type porous corrugated core. Then, vacuum-assisted molding technology is used: the bonded composite N-type corrugated structure is placed using the same process as peelable fabric, breathable felt, and vacuum bag. It is then placed in an incubator, and an external vacuum pump is used to evacuate the air, ensuring the sample is under vacuum throughout the curing process. The temperature parameters are as follows: first, heat at a rate of 3℃ / min to 80℃ and hold for 30 minutes; then heat at a rate of 5℃ / min to 130℃ and hold at this temperature for 90 minutes. The incubator is then closed, and after cooling to 60℃, the incubator is opened and the vacuum pump is turned off. The sample is then removed.

[0050] The structure prepared by the above preparation method includes: upper and lower fixed baffles 1, the upper and lower fixed baffles 1 having T-shaped pressure blocks 5 on both sides of the lateral direction and side baffles 4 on both sides of the longitudinal direction; the space formed by the upper and lower fixed baffles 1, side baffles 4, and T-shaped pressure blocks 5 contains a full composite material N-type porous corrugated structure core, the full composite material N-type porous corrugated structure core including several trapezoidal molds 8, cuboid molds 9, and composite material prepreg 7; one end of the composite material prepreg 7 is placed on the cuboid mold 9, the starting end of the composite material prepreg 7 is flush with the cuboid mold 9 to ensure the correct fiber direction; the trapezoidal mold 8 is placed on the composite material prepreg 7, the right angle side of the trapezoidal mold 8 is attached to the cuboid mold 9, the bottom is facing up, to ensure that the composite material prepreg 7 is attached to the mold; the composite material prepreg 7 along... The top bottom is folded over and the beveled edge is attached. Then, another trapezoidal mold 8 is added, with the beveled edges of the two trapezoidal molds 8 touching each other. The top bottom of the newly added trapezoidal mold 8 faces upwards. The composite prepreg 7 is folded over along the top bottom and attached to the right-angled edge. Next, a cuboid mold 9 is placed in, and the composite prepreg 7 is first folded over along the short side of the mold and attached to the long side. The trapezoidal mold 8 is then placed in, with the right-angled edge attached to the cuboid mold 9, and the top bottom facing upwards. The composite prepreg 7 is folded over and attached to the beveled edge. The trapezoidal mold 8 is placed in, with the bottom edge facing upwards. The beveled edges of the two trapezoidal molds 8 touch each other, and the prepreg is folded over along the top bottom and attached to the right-angled edge. Finally, the cuboid mold 9 is placed in, and the composite prepreg is folded over along the short side of the mold and attached to the long side, forming one unit cell of the all-composite N-type porous corrugated structure core. Multiple unit cells are repeated to form the all-composite N-type porous corrugated structure core. In this embodiment, eight unit cells are used.

[0051] like Figure 5 As shown, Figure 5 This is a comparison diagram of the out-of-plane compressive strength of corrugated structures in embodiments of the present invention; where A is the N-type porous corrugated structure of the asphalt-based glass fiber all-composite material prepared in the embodiment, and B is the traditional N-type porous corrugated structure of the asphalt-based glass fiber all-composite material. The present invention achieves mold-based production of complex structures and simultaneously solves the problem of mold and prepreg bonding. Under constant density, the out-of-plane compressive stiffness of the all-composite N-type porous corrugated structure is increased by more than 30% compared to the traditional corrugated structure.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an all-composite N-type porous corrugated structure, characterized in that, The method is as follows: Step 1: Pretreatment of composite prepreg. First, use a prepreg cutter to cut the composite prepreg. Step 2: Laying up the composite prepreg; Step 3: Assembly of the all-composite N-type porous corrugated structure core; First, place the rectangular mold (9) on the two fixing screws (10), and fix the lower end of the fixing screws (10) with fixing nuts (11) to prevent the mold from slipping; Then, place one end of the prepreg (7) of the composite material into the cuboid mold (9), with the starting end of the prepreg (7) flush with the cuboid mold (9) to ensure the correct fiber direction; place the trapezoidal mold (8) on the prepreg (7), with the right-angled side of the trapezoidal mold (8) and the cuboid mold (9) in contact, with the bottom facing up, to ensure that the prepreg (7) of the composite material is in contact with the mold; fold the prepreg (7) along the top bottom and attach it to the oblique side, and then add another trapezoidal mold (8), with the oblique sides of the two trapezoidal molds (8) in contact with each other, with the top bottom of the newly added trapezoidal mold (8) facing up, and fold the prepreg (7) along the top bottom and attach it to the right-angled side; Then, the prepreg (7) is placed in a cuboid mold (9), and the prepreg (7) is first folded along the short side of the mold and attached to the long side; the trapezoidal mold (8) is placed in, and the right-angled side is attached to the cuboid mold (9), with the top bottom facing up; the prepreg (7) is folded along the top bottom and attached to the oblique side; the trapezoidal mold (8) is placed in, with the bottom side facing up, and the oblique sides of the two trapezoidal molds (8) are attached to each other, and the prepreg is folded along the top bottom and attached to the right-angled side; then, the prepreg (7) is placed in a cuboid mold (9), and the prepreg (7) is folded along the short side of the mold and attached to the long side, forming a single cell of the all-composite N-type porous corrugated structure core; this process is repeated to form multiple single cells; Step 4: Curing of the all-composite N-type porous corrugated core; Step 5: Preparation of composite material panels. The composite material panels are formed using an autoclave curing process; the curing method is the same as that of the all-composite N-type porous corrugated structure core, and is the same as in Step 4. Step Six: Assembly of the all-composite N-type porous corrugated structure.

2. The method for preparing an all-composite N-type porous corrugated structure according to claim 1, characterized in that, In step one, unidirectional bitumen-based glass fiber prepreg is used. The length of the prepreg after cutting is 650mm long and 250mm wide.

3. The method for preparing an all-composite N-type porous corrugated structure according to claim 1, characterized in that, In step two, unidirectional composite prepreg is used for material layup; the fiber direction is set as 0° and the fiber perpendicular direction is set as 90°; the fiber bearing direction is used as the main direction and the constraint direction is used as the auxiliary direction. At the same time, the layup needs to meet the requirement of symmetrical layup to ensure that the structure does not deviate after curing; the layup is carried out in a 0° / 90° / 0° layup manner; during layup, a heating table is used to heat the prepreg to 50°C first, so that the resin on the surface of the prepreg is initially melted, and then the prepreg is laid up.

4. The method for preparing an all-composite N-type porous corrugated structure according to claim 1, characterized in that: Place the molds in the following order: cuboid mold (9) - trapezoidal mold (8) - trapezoidal mold (8) - cuboid mold (9) - trapezoidal mold (8) - trapezoidal mold (8); the other end of the mold after laying also needs to be fixed with screws (10) and nuts (11) to prevent the laid mold from moving; place the fixed all-composite corrugated core in the upper and lower fixed baffles (1), one end is fixed and constrained by the side baffle (4), and the other end is constrained by the T-shaped pressure block (5) to apply curing pressure during the curing process; put the extra screws (10) into the through holes of the T-shaped pressure block (5); Finally, use fixing bolts (2) and overall fixing nuts (6) to insert into the four through holes of the upper and lower fixing baffles (1) to constrain the entire structure and facilitate transportation.

5. The method for preparing an all-composite N-type porous corrugated structure according to claim 1, characterized in that, The all-composite N-type porous corrugated structure core is a single cell, and the all-composite N-type porous corrugated structure is set with 8 single cells.

6. The method for preparing an all-composite N-type porous corrugated structure according to claim 1, characterized in that, In step four, the assembled all-composite N-type porous corrugated structure core is cured using an autoclave curing process. The specific operation procedure is as follows: Wrap a breathable felt around the assembled core mold, then seal it with a vacuum bag, and place a vacuum valve on the sealed bag; place the entire assembly into an autoclave, connecting the vacuum valve to the autoclave's suction pipe; the curing parameters for the all-composite N-type porous corrugated structure core are: Autoclave temperature profile settings: First, the temperature is increased by 5°C per minute to 80°C. During this process, the autoclave is only evacuated without additional pressurization. After reaching 80°C, the temperature is maintained for 30 minutes, and the internal pressure is set to 0.1 MPa. After the process, the temperature is increased to 130°C at the same rate, and the internal pressure is maintained at 0.1 MPa. After reaching 130°C, the temperature is maintained for 90 minutes, and the internal pressure is set to 0.3 MPa. After the process, the autoclave is cooled while maintaining a pressure of 0.3 MPa at a cooling rate of 10°C per minute. After the sample temperature drops to 60°C, the pressure inside the autoclave is released, and the cured core is removed. The mold is then removed to obtain the all-composite N-type porous corrugated structure core.

7. The method for preparing an all-composite N-type porous corrugated structure according to claim 1, characterized in that, In step six, the adhesive film is pasted on the bonding platform of the composite material N-type porous corrugated core, and then vacuum-assisted molding technology is used: first, the bonded composite material N-type porous corrugated structure is placed in the same process of peelable cloth, breathable felt, and vacuum bag; then it is placed in the temperature chamber, and an external vacuum pump is used to evacuate the air to ensure that the sample is in a vacuum throughout the curing process. The temperature parameters are as follows: First, heat the sample at a rate of 3℃ / minute until it reaches 80℃, then hold it at that temperature for 30 minutes. Next, heat the sample at a rate of 5℃ / minute until it reaches 130℃, then hold it at that temperature for 90 minutes. After that, close the chamber and wait for it to cool down to 60℃ before opening the chamber and turning off the vacuum pump. Then, remove the sample.

8. A fully composite material N-type porous corrugated structure prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The structure includes: upper and lower fixed baffles (1), the upper and lower fixed baffles (1) have T-shaped pressure blocks (5) on both sides in the horizontal direction, and side baffles (4) on both sides in the vertical direction; the space formed by the upper and lower fixed baffles (1), side baffles (4), and T-shaped pressure blocks (5) is a core of N-type porous corrugated structure made of all composite materials; the side baffles (4) are fixed by side baffle bolts (3); the upper and lower fixed baffles (1) are fixed by integral fixing bolts (2) and integral fixing nuts (6).

9. The all-composite N-type porous corrugated structure according to claim 8, characterized in that, The mold placement order is as follows: the molds are placed in the order of cuboid mold (9) - trapezoidal mold (8) - trapezoidal mold (8) - cuboid mold (9) - trapezoidal mold (8) - trapezoidal mold (8).

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