Resin-based composite material box body and forming method thereof

Abstract

The invention discloses a resin-based composite material box and a forming method thereof. The box body comprises an inner lining layer and an outer lining layer, wherein an inner containing cavity is formed; the inner skin layer is attached to and wraps the outer side of the lining layer; the interlayer structure is laid on the outer side of the inner skin layer and comprises end opening frames at the two ends, a reinforcing rib set connected between the end frames and a filling core material filled in a gap; and the outer skin layer wraps the outer side of the sandwich structure to form an integrated structure. The air tightness is guaranteed through the lining, and the high specific stiffness and the light weight effect are provided through the composite sandwich structure. The box body is used as a mold for outer skin paving, and the box body is integrally formed through a co-gluing process, so that the problems that a special-shaped box body is difficult to form, heavy in weight and insufficient in rigidity are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of composite material manufacturing technology, specifically to a resin-based composite material box and its molding method. Background Technology

[0002] With the development of modern industry, carbon fiber reinforced composite materials have been widely used in aerospace and other fields due to their excellent mechanical properties and lightweight characteristics. Especially in the field of optical enclosures, while the strength requirements are relatively basic, the structural stiffness requirements are extremely high to ensure the stability of the optical path. Carbon fiber, with its excellent high stiffness characteristics and a specific gravity less than 1 / 4 that of steel, achieves significant weight reduction while ensuring extremely high rigidity. Carbon fiber reinforced epoxy resin matrix composites have the highest comprehensive indicators such as specific stiffness strength and specific modulus among existing structural materials, making them highly advantageous in fields with stringent requirements for density, stiffness, weight, and fatigue characteristics, as well as in applications requiring high temperature and chemical stability.

[0003] Currently, traditional optical enclosures are mostly made of welded or machined titanium alloy sheets, resulting in heavy weight and long processing cycles. Replacing the external titanium alloy sheets of existing optical enclosures with carbon fiber reinforced composite materials can significantly reduce the weight of the enclosure, achieving the weight reduction goal. However, pure composite material enclosures often fail to meet high standards in terms of airtightness, and due to the complex structure of the enclosure (including ribs, embedded parts, etc.), the molding process is difficult and prone to problems such as delamination and dimensional deviations.

[0004] Therefore, there is an urgent need for a box structure and molding method that can both ensure sealing and maximize the advantages of high rigidity and lightweight composite materials. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a resin-based composite material box and its molding method to solve the technical problems of complex structure, large weight and insufficient reliability in the prior art.

[0006] To achieve the above-mentioned technical objectives, this application adopts the following technical solution: In a first aspect, this application provides a resin-based composite material housing, comprising: An inner liner layer that encloses and forms a hollow internal cavity; An inner skin layer, which is attached to and covers the outer wall of the inner lining layer; A sandwich structure, laid on the outside of the inner skin layer, includes end frames, reinforcing ribs, and a filling core material. Two end frames are connected to both ends of the inner skin layer, the reinforcing ribs are connected between the two end frames, and the filling core material fills the gaps in the reinforcing ribs. An outer skin layer, which wraps around the outer wall of the sandwich structure and is connected to the sandwich structure to form an integrated structure.

[0007] In some embodiments of this application, the reinforcing rib group includes longitudinal ribs and circumferential ribs. Multiple longitudinal ribs extend along the axial direction of the inner lining layer and are connected at both ends to two end frames respectively. The circumferential ribs extend along the circumference of the inner lining layer and are located between the two end frames. The longitudinal ribs and the circumferential ribs are arranged alternately on the outer side of the inner lining layer.

[0008] In some embodiments of this application, the filling core material includes aluminum alloy honeycomb and foam components. The aluminum alloy honeycomb is filled in the rectangular area enclosed by the longitudinal ribs and the circumferential ribs, and the foam components are filled in the outer corner area of ​​the inner skin layer.

[0009] In some embodiments of this application, the end frame is made of carbon fiber braid and resin, and the inner surface of the end frame is bonded and fixed to the outer surface of the end of the inner skin layer by an adhesive film layer.

[0010] In some embodiments of this application, the material of the inner liner includes a titanium alloy, and the materials of the inner skin layer and the outer skin layer include a composite material of alternating layers of carbon fiber and epoxy resin.

[0011] In some embodiments of this application, a cover plate is also included, the cover plate comprising a titanium alloy plate and a carbon fiber composite material layer, the titanium alloy plate being detachably mounted on the outer skin layer, and the carbon fiber composite material layer being cured onto the titanium alloy plate.

[0012] Secondly, this application also provides a molding method for a resin-based composite material box, applicable to the resin-based composite material box as described in any embodiment of the first aspect, comprising the following steps: Carbon fiber prepreg is laid on the outer surface of the inner lining layer and cured by heating to form an inner liner structure with an inner skin layer. Position and bond the end frame on the inner liner structure, assemble the reinforcing rib group, and fill the gap of the reinforcing rib group with a core material to form a sandwich structure. Using the assembled sandwich structure box as the inner mold, an adhesive film is laid on its outer surface, and carbon fiber prepreg is laid layer by layer to form an outer skin layer preform. The outer skin of the box is pressurized and cured, and the outer skin layer and the sandwich structure are co-bonded and formed.

[0013] In some embodiments of this application, the molding method further includes: First, the end frames at both ends are bonded to the inner skin layer in parallel using adhesive film; After assembling the longitudinal ribs, measure the gap between the end frame and the inner skin layer, and adjust the number of adhesive film layers at the bonding surface of the end frame according to the gap value to compensate for the thickness.

[0014] In some embodiments of this application, the molding method further includes: Pre-assemble the circumferential stiffeners, aluminum alloy honeycomb, and longitudinal stiffeners, and check for interference between the components; Trim the aluminum alloy honeycomb that is causing interference until there is no interference fit; Finally, assemble the foam parts in the corner area and lay a film on the contact surface.

[0015] In some embodiments of this application, the molding method further includes: The box with the outer skin laid is vacuum-sealed and placed in an autoclave for pressure curing under a predetermined temperature and pressure curve.

[0016] Compared with the prior art, the beneficial technical effects of the technical solution provided in this application include: This invention ensures the airtightness of the enclosure by incorporating an inner lining layer. Furthermore, by constructing a composite sandwich structure consisting of an inner skin, end frame, reinforcing ribs, core material, and outer skin on the outside of the inner lining layer, the mechanical properties of this "sandwich" structure are utilized to significantly improve the enclosure's bending and torsional stiffness. Compared to traditional all-metal enclosures, it significantly reduces weight while maintaining the same stiffness; compared to pure composite enclosures, it solves the sealing problem. Simultaneously, the integrated structural design enables efficient molding, maximizing the advantages of each component material. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the embodiments will be briefly described below: Figure 1 This is a schematic diagram of the overall structure of the resin-based composite material box of the present invention; Figure 2 This is a schematic diagram of the structure of the inner skin layer after molding according to the present invention; Figure 3 This is a schematic diagram of the end frame structure of the present invention; Figures 4A-4B This is a schematic diagram of the reinforcing rib assembly of the present invention, wherein... Figure 4A For circumferential reinforcement, Figure 4B Longitudinal stiffeners; Figure 5 This is a schematic diagram showing the assembled sandwich structure of the present invention; Figure 6 This is a schematic diagram of the structure of the outer skin layer of the box after molding according to the present invention; Figure 7This is a schematic diagram of the structure after the box cover plate of the present invention is connected.

[0018] Figure label: 1-Inner lining layer, 2-Inner skin layer, 3-End frame, 4-Longitudinal rib, 5-Circumferential rib, 6-Aluminum alloy honeycomb, 7-Foam component, 8-Outer skin layer, 9-Cover plate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] Those skilled in the art will understand that, in this specification, the term "comprising" is an open-ended expression, meaning that the stated feature is present but other features are excluded. Directional terms such as "upper," "lower," "left," and "right" refer to exemplary directions based on the accompanying drawings. Features specified as "first" or "second" implicitly include one or more of that feature. Singular expressions can also be used in plural forms. "Multiple" means two or more. The terms "installed," "connected," and "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection via an intermediate medium, and it can be a connection within two components. Furthermore, "linked" can include wireless connections.

[0021] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a resin-based composite material box and its molding method to solve the technical problems of complex structure, large weight and insufficient reliability in the prior art.

[0022] To achieve the above-mentioned technical objectives, this application adopts the following technical solution: Reference Figures 1-7 As shown, this embodiment provides a resin-based composite material box. The main body of the box is designed with a titanium alloy liner and a composite material sandwich structure. Specifically, it includes: The inner lining layer 1, as an airtight barrier layer, is made of titanium alloy and surrounds a rectangular hollow internal cavity.

[0023] The inner skin layer 2 is rapidly laid and cured on the surface of the titanium alloy liner, and is attached to and wrapped around the outer wall of the inner liner layer 1.

[0024] The sandwich structure is located between the inner and outer skin layers, providing structural rigidity. The structure includes end frames 3 at both ends, reinforcing ribs (longitudinal ribs 4 and circumferential ribs 5) connecting the two end frames, and filling core material (aluminum alloy honeycomb 6 and foam component 7) filling the gaps between the ribs.

[0025] The outer skin layer 8 is a six-sided closed structure, wrapped around the outermost part of the sandwich structure, and integrally formed with the inner sandwich structure through co-bonding.

[0026] Working principle: The titanium alloy inner lining layer 1 utilizes the density of the metal material to prevent gas leakage and ensure a stable internal environment. The inner skin layer 2 serves as a transition layer, enhancing the bonding strength between the carbon fiber structure and the titanium lining. The reinforcing ribs in the sandwich structure form the load-bearing skeleton of the enclosure, bearing the main bending and torsional loads; the filling core material (aluminum honeycomb and foam) supports the skin to prevent buckling and transmits shear forces. The outer skin layer 8 encloses the entire structure, forming a continuous load-bearing skin.

[0027] This structure perfectly combines the sealing performance of titanium alloy with the high specific stiffness of carbon fiber composite materials. The enclosure is high in strength, lightweight (less than 1 / 4 the weight of steel), and structurally stable, meeting the stringent requirements of optical enclosures for both rigidity and sealing.

[0028] See Figure 4A , Figure 4B and Figure 5 This embodiment provides a detailed description of the reinforcing rib assembly. The reinforcing rib assembly includes longitudinal ribs 4 and circumferential ribs 5. The longitudinal ribs 4 extend along the length of the box body, i.e., the axial direction of the inner lining layer, and a total of eight ribs are provided. Each rib's two ends are connected to two end frames 3, serving as the main longitudinal stiffener. The circumferential rib 5 extends circumferentially along the inner lining layer, and one rib is provided, located between the two end frames. The longitudinal ribs 4 and circumferential ribs 5 are arranged alternately on the outside of the inner skin layer 2, forming a grid-like skeleton. Considering manufacturing process and structural rigidity, and to facilitate the filling of the honeycomb sandwich layer, the cross-sectional structure of both the longitudinal ribs 4 and the circumferential ribs 5 adopts a C-shaped structure.

[0029] The C-shaped cross-section rib structure ensures excellent bending moment of inertia while facilitating mold forming and subsequent filling and assembly of the honeycomb core material. The optimized 8-vertical-1-ring layout achieves weight reduction while meeting the structural rigidity requirements of the optical enclosure.

[0030] This embodiment provides a detailed description of the filling core material. The filling core material includes an aluminum alloy honeycomb 6 and a foam component 7. The aluminum alloy honeycomb 6 fills the rectangular planar area vacated by the longitudinal ribs 4 and the circumferential ribs 5, and the aluminum honeycomb is cut according to the size of the vacated area. The foam component 7 uses polymethacrylamide (PMI) to support the foam and fills the outer side of the corner (R corner) area of ​​the inner skin layer 2.

[0031] The aluminum honeycomb structure is lightweight and sturdy, effectively absorbing and dispersing external forces, improving the impact resistance and out-of-plane stiffness of the enclosure. Due to the curvature, it is inconvenient to fill the corners with honeycomb; therefore, PMI foam is used for filling and transition, ensuring the continuity of the sandwich structure and the flatness of the outer skin, and avoiding corner void defects.

[0032] See Figure 3 This embodiment provides a detailed description of the end frame. The end frame 3 is a prefabricated body, using 2.5D carbon fiber braid as reinforcement and low-viscosity resin. It is manufactured using resin transfer molding (RTM) technology. Temperature is controlled during resin injection to ensure the viscosity of the resin and slow-drying curing agent is between 0.1 Pa•s and 0.3 Pa•s. After molding, the shape is machined to the required dimensions. During assembly, its inner surface is sandblasted, and then a layer of adhesive film is applied and bonded to the outer end surface of the inner skin layer 2.

[0033] The use of 2.5D braided fabric combined with RTM technology solves the problem of easy delamination in traditional laminated boards, improving the interlaminar shear strength and overall integrity of the end frame. Low-viscosity resin ensures full impregnation of the braided fabric. Sandblasting and adhesive film bonding guarantee a high-strength connection between the end frame and the inner skin, capable of withstanding end loads.

[0034] This embodiment provides a detailed description of the housing materials and layup. The inner lining layer 1 is made of titanium alloy sheet of appropriate thickness (e.g., about 1.5 mm) welded or formed. Both the inner skin layer 2 and the outer skin layer 8 are made of carbon fiber-epoxy resin prepreg. In terms of layup design, layers are laid alternately at angles of 0°, 90°, and ±45°.

[0035] Carbon fiber reinforced epoxy resin matrix composites have extremely high specific strength and specific modulus. The 0° / 90° / ±45° layup design gives the skin relatively balanced mechanical properties (quasi-isotropic) in all directions, which can withstand not only axial tension and compression, but also shear and torsion, ensuring the stability of the enclosure under complex stress environments.

[0036] See Figure 6 and Figure 7 This embodiment provides a detailed description of the cover plate structure. The enclosure also includes cover plates 9, which are located at both ends of the main enclosure structure. Cover plates 9 are constructed using a combination of titanium alloy inner lining and carbon fiber composite material. The inner side uses a 1.5mm thick titanium alloy plate, while the outer composite material layer is 20mm thick and is made by lay-up and curing carbon fiber composite material. After the cover plates 9 are manufactured, they are connected to the end frame 3 via machined threaded holes and bolts.

[0037] The inner side of the cover plate 9, made of titanium alloy, forms a continuous metal sealing interface with the inner titanium alloy lining layer 1 of the main body of the enclosure (in conjunction with sealing rings, etc.), ensuring overall airtightness. The 20mm thick carbon fiber layer on the outer side provides extremely high planar rigidity, preventing the cover plate from deforming under pressure difference, while also providing sufficient holding force for bolt connections.

[0038] This embodiment provides a method for molding a resin-based composite material box. The method includes the following steps: S1. Inner Liner Preparation: First, the titanium alloy inner liner 1 is rapidly laid on the surface. Carbon fiber-epoxy resin prepreg is laid layer by layer at 0°, 90°, and ±45°. After bag sealing, it is pressurized and cured in an autoclave to form an inner liner structure with an inner skin layer 2.

[0039] S2. Sandwich structure assembly: Position and bond the end frame 3 on the inner liner structure (sandblasting, applying adhesive film), assemble the reinforcing rib group (8 longitudinal ribs, 1 ring rib), and fill the gaps between the ribs with aluminum alloy honeycomb 6 and PMI foam 7.

[0040] S3. Outer Skin Covering: The assembled sandwich structure box is used as a covering mold (inner mold) for direct covering. After covering the entire outer surface of the box sandwich structure with a layer of adhesive film, carbon fiber prepreg (0°, 90°, ±45°) is then covered to form the outer skin prefabricated body.

[0041] S4. Overall Co-curing: The box body with the completed outer skin is sealed in a bag and placed in an autoclave for pressure curing. The entire outer skin of the box body is integrally formed with the sandwich structure through co-bonding.

[0042] This method creatively utilizes a semi-finished box body as a mold, eliminating the need for complex large external molds and reducing tooling costs. Through a co-bonding process, the outer skin, core material, and ribs are cured and connected in one step, resulting in better interfacial bonding performance than secondary bonding, thus improving the overall integrity and reliability of the structure.

[0043] This embodiment supplements the assembly details of the end frame. In step 2, the end frame 3 is assembled first. Its inner surface is sandblasted, and then a layer of adhesive film is laid. The end frames at both ends are first glued parallel to the inner skin layer 2 to ensure the parallelism of the two end frames and their fit with the inner skin. When assembling the longitudinal ribs 4, the eight longitudinal ribs are pre-installed and positioned with the end frame. Then, the gap between the end frame 3 and the inner skin layer 2 is measured with a feeler gauge, and the adhesive film is adjusted on the end frame according to the size of the gap (increasing or decreasing the number of adhesive film layers).

[0044] By using the method of "feeler gauge measurement + adhesive film compensation", the assembly gap was effectively eliminated, the internal stress caused by forced assembly was avoided, and the bonding quality and positional accuracy of the end frame and inner skin were guaranteed.

[0045] This embodiment supplements the details of the core material trial assembly. Before formal bonding, a trial assembly is performed: the circumferential ribs 5 are trial-assembled with the aluminum alloy honeycomb 6 and the longitudinal ribs 4 to observe for any interference. If interference exists, the aluminum alloy honeycomb 6 should be trimmed to ensure that the circumferential ribs, longitudinal ribs, and aluminum honeycomb can be assembled with each other, and the assembly positions should be marked. Subsequently, the PMI foam 7 with the radius of curvature of each surface is assembled, with the curved surface where the supporting foam is located being assembled last. The curved areas between the ribs and the honeycomb or supporting foam are assembled and positioned by bonding the adhesive film between the ribs and the honeycomb or supporting foam.

[0046] Trial assembly and trimming processes are crucial for ensuring the quality of complex sandwich structures. They prevent skin bulging or core crushing caused by excessively large core material dimensions, and also prevent resin-rich areas or voids caused by excessively small dimensions, thus ensuring the density and uniformity of the internal structure.

[0047] This embodiment provides a detailed description of the autoclave curing process. Before curing, a vacuum leak test is required: Evacuate the system until the vacuum level reaches -90 kPa to -100 kPa, stabilize the pressure for 10 minutes, then turn off the vacuum source for 5 minutes. If the vacuum drop is less than 2 kPa, the autoclave can be used for curing.

[0048] The specific curing process is as follows: Vacuum requirement: Vacuum must be maintained throughout the process, with a vacuum level ≤ -kPa.

[0049] Temperature requirements: Heat to 90℃ at a heating rate of 0.5℃ / min (±0.25℃ / min), hold for 5 hours (±10 min) with a temperature difference of 5℃; after holding, cool down to below 60℃ at a cooling rate of 0.5~2℃ / min.

[0050] Pressure requirements: When the temperature reaches a certain value (usually before the resin gels), start pressurizing at a rate of 0.03 MPa / min (±0.01 MPa / min) until the pressure reaches 0.6 ±0.01 MPa. After the temperature drops below 60°C, release the pressure and open the can at a rate of 0.05 MPa / min (±0.01 MPa / min).

[0051] By employing a low-temperature (90℃) and long-duration (5h) curing regime, coupled with specific heating and cooling rates and pressurization timing, the flow of resin and the discharge of volatiles can be effectively controlled, preventing the formation of pores and delamination in thick-walled or sandwich structures. Strict vacuum leak detection standards ensure the reliability of the molding process.

[0052] In the outer skin covering process, a layer of adhesive film is applied to the entire outer surface of the cabinet sandwich structure. In addition to its adhesive function, this film also serves as a stress buffer layer and a resin-rich layer. This adhesive film layer not only enhances the interfacial adhesion between the outer skin and the aluminum honeycomb and reinforcing ribs, but also effectively prevents honeycomb grid imprints from showing through to the outer skin surface, significantly improving the appearance quality of the cabinet.

[0053] A viscoelastic damping film is disposed at the bonding interface between the aluminum alloy honeycomb 6 and the inner skin layer 2 or the outer skin layer 8. The optical enclosure is extremely sensitive to micro-vibrations. By introducing a polymer viscoelastic damping film at the interface between the skin and the core material, the vibration energy is dissipated by its shear hysteresis effect, which significantly improves the structural modal damping ratio of the enclosure, suppresses micro-vibrations, and enhances the imaging stability of the optical system.

[0054] After the outer skin has cured, the outer surface and end faces of the enclosure are precision machined. The machining process after curing eliminates dimensional deviations caused by curing deformation, ensuring the final dimensional accuracy of the enclosure and meeting the stringent tolerance requirements of precision optical instruments for the mounting reference surface.

[0055] There are eight longitudinal stiffeners 4, evenly spaced along the long axis of the box; there is one circumferential stiffener 5, located at the middle of the box's length. This specific topological structure of eight longitudinal and one circumferential stiffeners is an optimized result for the stress characteristics of a cuboid box. While ensuring bending and torsional stiffness, it avoids excessive stiffeners that add unnecessary weight, making it a design with superior structural efficiency.

[0056] The cover plate 9 has a titanium alloy plate thickness of 1.5mm and a carbon fiber composite material layer thickness of 20mm. This differentiated thickness ratio design utilizes the 20mm thick composite material layer to bear the main mechanical connection load and bending load, while the 1.5mm thin titanium layer focuses on the sealing function, achieving decoupling optimization of the cover plate's functions and reducing weight.

[0057] The vacuum leak test standard before curing is set as follows: after evacuating to -90kPa to -100kPa and stabilizing the pressure for 10 minutes, disconnect the vacuum source for 5 minutes. If the vacuum drop is less than 2kPa, the seal is considered qualified. This standard quantifies the airtightness requirements of the vacuum system, effectively preventing product scrap due to minor damage to the vacuum bag (such as excessive porosity or insufficient pressure), and is a necessary process control means to obtain high-quality composite material parts.

[0058] Compared with the prior art, the beneficial technical effects of the technical solution provided in this application include: The resin-based composite material housing and its molding method provided by this invention successfully resolve the contradiction between high rigidity, lightweight, and high airtightness in optical housings by organically combining a titanium alloy liner with a carbon fiber reinforced composite material sandwich structure, along with refined assembly processes and optimized curing regimes. Furthermore, this invention significantly reduces manufacturing costs by utilizing the housing itself as a mold, making it a promising candidate for applications in high-end aerospace equipment and precision instruments.

[0059] Those skilled in the art will understand that the steps, measures, and schemes in the various operations, methods, processes, and procedures discussed in this application can be alternated, modified, rearranged, decomposed, combined, or deleted.

[0060] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of the claims of this application.

Claims

1. A resin based composite box, characterized by, The resin-based composite box body comprises: an inner liner layer, which forms a hollow inner accommodating cavity; an inner skin layer, which is attached to the outer side wall of the inner liner layer; a sandwich structure, which is arranged outside the inner skin layer, comprises end port frames, a reinforcing rib group and a filling core material, the two end port frames are connected to the two ends of the inner skin layer, the reinforcing rib group is connected between the two end port frames, and the filling core material is filled in the interspace of the reinforcing rib group; and an outer skin layer, which is wrapped on the outer side wall of the sandwich structure and is connected with the sandwich structure to form an integrated structure.

2. The resin based composite box of claim 1, wherein, The reinforcing rib group comprises longitudinal ribs and annular ribs, the longitudinal ribs extend along the axial direction of the inner liner layer and are connected to the two end port frames respectively, the annular ribs extend along the circumferential direction of the inner liner layer and are located between the two end port frames, and the longitudinal ribs and the annular ribs are arranged outside the inner skin layer in an interlaced manner.

3. The resin based composite box of claim 2, wherein, The filling core material comprises aluminum alloy honeycombs and foam pieces, the aluminum alloy honeycombs are filled in the rectangular area surrounded by the longitudinal ribs and the annular ribs, and the foam pieces are filled outside the corner areas of the inner skin layer.

4. The resin based composite box of claim 1, wherein, The material of the end port frame comprises carbon fiber woven bodies and resin, and the inner surface of the end port frame is fixedly bonded to the outer surface of the end of the inner skin layer through a film layer.

5. The resin based composite box of claim 1, wherein, The material of the inner liner layer comprises titanium alloy, and the materials of the inner skin layer and the outer skin layer comprise a composite material formed by alternately stacking multiple layers of carbon fiber and epoxy resin.

6. The resin based composite box of claim 1, wherein, Further comprising a cover plate, which comprises a titanium alloy plate and a carbon fiber composite material layer, the titanium alloy plate is detachably mounted on the outer skin layer, and the carbon fiber composite material layer is solidified on the titanium alloy plate.

7. A method of forming a resin-based composite box, characterized by, The resin-based composite box body is suitable for the resin-based composite box body according to any one of claims 1-6, and comprises the following steps: carbon fiber prepregs are laid on the outer surface of the inner liner layer to form an inner container structure with an inner skin layer after heating and curing; the end port frames are positioned and bonded on the inner container structure, the reinforcing rib group is assembled, and the filling core material is arranged in the interspace of the reinforcing rib group to form a sandwich structure; the box body with the assembled sandwich structure is used as an inner mold, a film is integrally laid on the outer surface of the inner mold, carbon fiber prepregs are laid layer by layer to form an outer skin layer preform; the box body with the completed outer skin layer is subjected to pressure curing, and the outer skin layer and the sandwich structure are co-bonded to form a molded product.

8. The method of forming a resin-based composite box according to claim 7, wherein, The molding method further comprises: the end port frames at both ends are bonded in parallel on the inner skin layer through a film layer; after the longitudinal ribs are assembled, the gap value between the end port frames and the inner skin layer is measured, and the number of film layers at the bonding surface of the end port frames is increased or decreased for thickness compensation according to the gap value.

9. The method of forming a resin-based composite box according to claim 8, wherein, The molding method further comprises: the annular ribs, the aluminum alloy honeycombs and the longitudinal ribs are pre-assembled, and the interference between the components is checked; the aluminum alloy honeycombs that interfere with each other are trimmed until there is no interference fit; finally, the foam pieces in the corner areas are assembled, and a film is laid on the contact surface.

10. The method of forming a resin-based composite box according to claim 7, wherein, The molding method further comprises: The box with the outer skin laid up is vacuum bagged and placed in an autoclave for pressurized curing under predetermined temperature and pressure profiles. The box with the outer skin laid up is vacuum bagged and placed in an autoclave for pressurized curing under predetermined temperature and pressure profiles.

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