A ribbed carbon fiber composite beam for commercial vehicles and its co-curing preparation process

Abstract

This invention relates to the field of composite material manufacturing, and discloses a ribbed carbon fiber composite crossbeam for commercial vehicles and its co-curing preparation process. The crossbeam includes: a rear crossbeam body, made of carbon fiber woven fabric and epoxy resin matrix through a co-curing process; ribs, located at the right-angle bends of the crossbeam body, integrally formed with the crossbeam body through a co-curing process; and a metal bushing, embedded in the crossbeam body for bolted assembly, the bushing being integrally formed with the body through a co-curing process. The preparation process includes: mold preparation, rib positioning, body laying, bushing installation, vacuuming, curing, and post-treatment. This invention, through the lightweight and high-strength characteristics of carbon fiber composite materials, combined with the optimized design of the ribs and metal bushings, achieves lightweight, high-strength, and improved fatigue performance of the rear crossbeam for commercial vehicles, exhibiting good environmental adaptability and broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of composite material manufacturing technology, specifically to a ribbed carbon fiber composite beam for commercial vehicles and its co-curing preparation process. Background Technology

[0002] With the development of the automotive industry, lightweighting has become a crucial direction in the design and manufacturing of commercial vehicles. Carbon fiber reinforced resin matrix composites, due to their superior properties such as high specific strength, high specific modulus, and corrosion resistance, are increasingly being used in automotive structural components. Compared to traditional metal materials, carbon fiber composites can significantly reduce component weight while maintaining strength and stiffness, thus possessing broad application prospects in the commercial vehicle sector.

[0003] However, most traditional commercial vehicle rear crossbeams are made of metal materials, such as steel and aluminum alloys. While these materials possess certain strength and rigidity, their weight is significant, limiting the lightweight design of the entire vehicle. Furthermore, in scenarios requiring complex load conditions, the stress concentration problem of traditional metal crossbeams is particularly pronounced, especially at right-angle turns, where fatigue failure is likely to occur, affecting service life. Simultaneously, due to the limitations of metal materials in terms of fatigue performance and environmental adaptability, their performance may degrade after prolonged use due to fatigue cracks or corrosion.

[0004] While existing composite material-based crossbeam technologies for commercial vehicles attempt to leverage the lightweight advantages of carbon fiber composites, they still have several shortcomings in practical applications. For example, the stiffness and strength of composite crossbeams often fail to meet design requirements in localized areas, especially at bends or bolted joints. Traditional mechanical connection methods are prone to wear or failure at the joints, while also increasing manufacturing costs. Furthermore, existing processes often require multiple separate processing steps, resulting in inefficiency and difficulty in ensuring consistent product quality.

[0005] Therefore, how to utilize the excellent properties of carbon fiber composite materials to design a commercial vehicle rear crossbeam structure that simultaneously possesses lightweight, high strength, and high reliability, and how to overcome the shortcomings of traditional structures and processes through optimized manufacturing processes, are urgent problems to be solved in the current technological field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a ribbed carbon fiber composite beam for commercial vehicles and its co-curing preparation process, which solves the problems of large weight, stress concentration, insufficient fatigue performance, and low manufacturing efficiency of existing commercial vehicle rear beams.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a ribbed carbon fiber composite crossbeam for commercial vehicles, comprising:

[0008] The main body of the rear crossbeam is made of a prepreg composite of carbon fiber woven fabric and epoxy resin matrix through a co-curing process;

[0009] The ribs are located at the right-angle turns of the main body of the crossbeam and are integrally formed with the main body of the crossbeam through a co-curing process.

[0010] Metal bushings are embedded in the main body of the crossbeam and are used for the assembly of connecting bolts. The metal bushings and the main body of the crossbeam are cured simultaneously to form a whole.

[0011] Preferably, the carbon fiber prepreg includes:

[0012] 0° / 90° biaxial prepreg is used to provide flexural strength;

[0013] 45° / -45° biaxial prepreg is used to provide shear resistance.

[0014] Preferably, the prepreg is laid alternately with different fiber directions to form a multilayer composite material structure.

[0015] Preferably, the rib plate has a C-shaped structure, and the material of the rib plate is the same as that of the rear crossbeam body.

[0016] Preferably, both the rib plate material and the rear crossbeam body are composed of T400-12K carbon fiber woven fabric and epoxy resin matrix.

[0017] Preferably, the metal bushing is made of aluminum alloy and is fixed in the mold during installation by a positioning device so that it is cured synchronously with the main body of the rear crossbeam.

[0018] Preferably, the fiber mass content of the carbon fiber prepreg fabric of the rear crossbeam body is 58% to 65%.

[0019] This invention also provides a co-curing preparation process for ribbed carbon fiber composite beams for commercial vehicles, comprising the following steps:

[0020] Mold preparation: Design and manufacture an integral, modular mold, including upper and lower molds, left and right molds, and a release module; before laying, clean the mold surface and apply a release agent and release wax;

[0021] Bushing installation: Place the aluminum alloy metal bushing at the predetermined position inside the mold and fix it with adhesive;

[0022] Rib positioning: Cut carbon fiber prepreg according to the shape of the rib, lay it on the rib groove limit on the upper surface of the mold and compact it;

[0023] Main body laying: Alternately lay 0° / 90° and 45° / -45° carbon fiber prepreg to the designed thickness, and lay unidirectional prepreg at right angles for reinforcement;

[0024] Vacuuming: Performing vacuum treatment to remove air bubbles from the layup;

[0025] Curing: Place the assembled mold into a preheated 60℃ molding press and cure it according to the preset temperature, pressure and time parameters;

[0026] Post-processing: After curing, cool to room temperature, demold, and then trim and polish the beam components to ensure surface quality and dimensional accuracy.

[0027] Preferably, the curing process is carried out at a temperature of 130℃ to 150℃, a pressure of 30 to 100 kg, and a curing time of 1 hour to 2 hours.

[0028] Preferably, the curing process employs a multi-stage heating process, including:

[0029] In the first stage, the temperature is increased from room temperature to the pre-curing temperature at a rate of 2℃ / min.

[0030] The second stage involves maintaining the pre-curing temperature for a certain period of time.

[0031] In the third stage, the temperature is increased to the final curing temperature at a heating rate of 1℃ / min.

[0032] This invention provides a ribbed carbon fiber composite beam for commercial vehicles and its co-curing preparation process. It offers the following advantages:

[0033] 1. This invention significantly reduces the weight of the rear crossbeam by using carbon fiber composite material as the main material and combining it with an integrated design of ribs and metal bushings. While meeting strength and stiffness requirements, it reduces the overall vehicle weight, thereby improving fuel economy and reducing emissions, aligning with the trend of lightweighting in commercial vehicles.

[0034] 2. This invention utilizes an alternating layering design of carbon fiber prepreg in the 0° / 90° and 45° / -45° directions, with unidirectional prepreg reinforcement at right-angle turns, significantly enhancing the overall structural strength and stiffness of the rear crossbeam. Especially in stress concentration areas, the C-shaped ribs effectively disperse stress, improving local fatigue life.

[0035] 3. This invention embeds an aluminum alloy metal bushing within the main body of the crossbeam and employs a roughened surface design and co-curing molding process, forming a strong interface bond between the metal bushing and the composite material body. This design avoids wear caused by direct contact between bolts and carbon fiber, enhancing the reliability and long-term durability of the bolted connection.

[0036] 4. This invention significantly improves the stress concentration problem at right-angle bends of the crossbeam by setting ribs and unidirectional prepreg reinforcement at the corners. The co-curing design of the ribs and the main body enhances the local stiffness and strength of this area, effectively reducing the risk of fatigue cracks and thus extending the service life of the crossbeam.

[0037] 5. The co-curing process enables the ribs, metal bushings, and crossbeam body to be integrally molded, eliminating the need for traditional mechanical connections or subsequent drilling processes, thus significantly simplifying the production process. This process not only reduces manufacturing costs but also improves production efficiency, making it suitable for mass production.

[0038] 6. The design and manufacturing process of this invention are not only applicable to the rear crossbeams of commercial vehicles, but can also be extended to other structural components with high strength and lightweight requirements, such as rail transit components and aerospace structural components, demonstrating good technical versatility and industrialization potential. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0040] Figure 2 This is a schematic diagram of the process flow of the present invention.

[0041] Among them, 1. Rear crossbeam main body; 2. Rib plate; 3. Metal bushing. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Please see the appendix Figure 1 This invention provides a ribbed carbon fiber composite crossbeam for commercial vehicles, aiming to achieve a lightweight design for the rear crossbeam of commercial vehicles while ensuring high strength, high stiffness, and excellent fatigue performance during use. The entire crossbeam is manufactured through a co-curing process, achieving efficient integration of the ribs 2, metal bushings 3, and the main body, thereby improving production efficiency, reducing manufacturing costs, and significantly improving mechanical properties.

[0044] like Figure 1 As shown, the ribbed crossbeam made of carbon fiber composite material for commercial vehicles mainly includes a rear crossbeam body 1, ribs 2, and metal bushings 3. The following is a detailed description of each component.

[0045] Rear crossbeam main body 1

[0046] In this embodiment, the rear crossbeam body 1 is made of a prepreg composite of carbon fiber woven fabric and epoxy resin matrix through a co-curing process, which has the structural characteristics of lightweight and high strength. Its design meets the mechanical performance requirements of the rear crossbeam of commercial vehicles under complex working conditions.

[0047] As an alternative, the carbon fiber prepreg of the rear crossbeam body 1 is made of T400-12K biaxial carbon fiber fabric with fiber orientations of 0° / 90° and 45° / -45° to meet the strength requirements of the crossbeam under bending and shear loads. The prepreg with the 0° / 90° fiber orientation primarily provides the crossbeam with bending resistance, while the prepreg with the 45° / -45° fiber orientation enhances its shear resistance.

[0048] In some embodiments, the carbon fiber prepreg fabric of the rear crossbeam body 1 is laid alternately according to the fiber direction to form a multi-layer composite structure, thereby further optimizing the overall strength and stiffness. Specifically, the alternating direction during laying can reduce interlayer stress concentration and avoid the deterioration of mechanical properties in local areas.

[0049] The matrix material of the rear crossbeam body 1 is epoxy resin, which has excellent adhesion, fatigue resistance, and durability, ensuring reliable bonding between carbon fiber layers. Understandably, epoxy resin can also be modified according to specific performance requirements, such as by adding toughening agents (e.g., liquid rubber or block copolymers) to improve the impact resistance of the composite material.

[0050] As one possible approach, 1% to 5% by weight of nano-silicates or carbon nanotubes can be incorporated into the epoxy resin to enhance interfacial strength and thermal conductivity. The use of these additives can further optimize the overall performance of the rear beam body 1, particularly its stability under long-term fatigue loads or high-temperature environments.

[0051] It should be noted that the ply thickness of the rear crossbeam body 1 is designed according to the specific load requirements of the vehicle. In some embodiments, the fiber density of the ply is 190 g / m². 2 Up to 250g / m 2 To achieve a balance between weight and strength, the thickness and orientation of the ply can be optimized through mechanical simulation calculations to meet the performance requirements of different vehicle models.

[0052] As a possible structural design, the right-angle turn of the rear crossbeam body 1 is a critical stress concentration area. Therefore, in this embodiment, a unidirectional prepreg is used to reinforce this area, which is then bonded to other layers to form a complete composite material structure. This reinforcement measure can significantly reduce the risk of stress concentration at the corner and extend the fatigue life of the crossbeam.

[0053] It should be noted that the fiber content of the carbon fiber prepreg in the main body 1 of the rear crossbeam is 58% to 65% to ensure that the finished structure can maintain a certain toughness, while the fiber and the matrix material have sufficient interfacial bonding strength, and the overall mechanical properties will not be reduced due to excessive matrix material.

[0054] Understandably, the rear crossbeam body 1 requires precise mold design and layup sequence control during fabrication to ensure that the fiber orientation aligns with mechanical requirements. This design maximizes the utilization of carbon fiber's high specific strength and specific modulus, enabling the crossbeam body to achieve lightweighting while maintaining performance.

[0055] In this embodiment, the rear crossbeam body 1 can withstand large bending and shear loads during use, and its multi-directional ply structure can effectively resist stress in all directions, thereby ensuring the reliability of the crossbeam under complex working conditions.

[0056] Rib 2

[0057] In this embodiment, the rib plate 2 is set at the right-angle turn of the rear crossbeam body 1 and is integrally formed with the crossbeam body through a co-curing process. Its main function is to enhance the rigidity and strength of this area in order to cope with the stress concentration problem at the right-angle turn.

[0058] Alternatively, rib 2 can be made of the same material as the rear crossbeam body 1, namely, T400-12K carbon fiber prepreg. This material combination offers excellent mechanical properties, providing high strength and stiffness while maintaining a lightweight design, thus significantly improving structural performance at corners.

[0059] Specifically, considering the complex load conditions of actual vehicles and the constrained installation position of the crossbeam, the load can be regarded as a small torsion with randomly varying amplitude and frequency. Adding ribs will greatly increase the overall torsional stiffness of the crossbeam, thereby reducing the overall torsional deformation of the crossbeam and thus reducing the overall load. Furthermore, the geometric design of rib 2 is C-shaped, and its arc structure can effectively disperse stress concentration at right-angle turns and improve overall strength through close integration with the crossbeam body. In some embodiments, the thickness and dimensions of rib 2 are optimized according to the specific load requirements of the vehicle to achieve a balance between weight and performance.

[0060] In one possible implementation, the layup design of rib 2 follows the principle of alternating fiber directions to further improve mechanical properties. For example, the rib 2 layup uses alternating layers of carbon fiber prepreg in 0° / 90° and 45° / -45° directions, with each layer bonded to the others by epoxy resin inherent in the carbon fiber prepreg, thereby forming a stable multilayer structure.

[0061] It should be noted that the layup direction of rib 2 is specifically matched with the fiber direction of the rear crossbeam body 1 to ensure uniform interlaminar stress transfer at the joint and avoid structural weakening or delamination caused by mismatched directions. Understandably, this layup design provides higher strength and stability under bending and torsional loads.

[0062] Alternatively, the edge of rib 2 is designed with a certain transition arc to create a smooth transition at the connection with the rear crossbeam body 1. This design can further reduce stress concentration at the connection and improve the interface bonding performance between rib 2 and the body.

[0063] In some embodiments, to further improve the impact resistance of the rib 2, a certain proportion of toughening agent, such as 2% to 8% by mass of liquid rubber or block copolymer, can be added to the epoxy resin matrix of the rib 2. These additives can effectively improve the toughness of the rib 2 under dynamic loads and avoid structural failure caused by impact loads.

[0064] It should be noted that the fiber orientation accuracy of rib 2 directly affects its mechanical properties. In this embodiment, the fiber orientation deviation is precisely controlled to not exceed ±2° to ensure that the mechanical properties of rib 2 are fully utilized along the design direction in actual use. This precision control is achieved through specialized tools and equipment used in material cutting and layup processes.

[0065] Understandably, after the rib plate 2 and the main beam are integrally molded through a co-curing process, their overall performance is significantly improved compared to the traditional separate design with mechanical connections. The integrated molding structure not only avoids the stress concentration problem caused by mechanical connections, but also simplifies the production process and improves production efficiency.

[0066] In some possible embodiments, the surface of the rib 2 may be designed with a special textured structure to enhance the bonding strength. These textures can increase the interface area between the rib 2 and the crossbeam body, thereby further improving the interfacial bonding force. This design is particularly suitable for crossbeams in commercial vehicles that need to withstand large loads.

[0067] In this embodiment, the rib plate 2 is mainly used to improve the fatigue performance at the right-angle turn of the rear crossbeam and effectively extend the service life of the crossbeam.

[0068] Metal bushing 3

[0069] In this embodiment, the metal bushing 3 is embedded within the main body 1 of the rear beam for bolt connection and assembly, thereby addressing the issues of wear, stress concentration, and fatigue failure that may result from direct contact between the carbon fiber composite material and the metal bolts. The metal bushing 3 is integrated with the main body of the beam through a co-curing process, ensuring precise positioning and high-strength connection performance.

[0070] As an alternative, the metal bushing 3 is made of aluminum alloy. Aluminum alloy has high strength and corrosion resistance, while its low density and certain wear resistance allow it to meet structural strength and long-term service requirements without significantly increasing the overall weight. Understandably, the choice of aluminum alloy balances lightweight design with durability requirements, making it a preferred material for commercial vehicle crossbeams.

[0071] Specifically, the outer surface of the metal bushing 3 is roughened, for example by sandblasting or etching, to enhance its interfacial bonding with the carbon fiber composite material. Exemplarily, this roughening process allows the epoxy resin matrix to better fill the microstructure of the metal bushing 3 surface during co-curing, thereby significantly improving the bushing's embedding stability.

[0072] In some embodiments, the metal bushing 3 has a cylindrical geometry, and its outer diameter matches the pre-drilled hole diameter in the beam body to achieve a precise fit. To further improve the bonding performance of the bushing, its ends are designed with a chamfered structure, which can reduce stress concentration during curing and improve the flowability and permeability of epoxy resin at the interface.

[0073] As one possible implementation, the inner diameter of the metal bushing 3 is designed according to the specifications of the bolts it is fitted with, and its inner surface is anodized to improve wear resistance and corrosion resistance. Understandably, the surface finish and dimensional accuracy of the inner diameter play a crucial role in the strength and long-term reliability of the bolted connection.

[0074] It should be noted that the axial length of the metal bushing 3 is adjusted according to the thickness of the crossbeam body. In some embodiments, the length of the metal bushing 3 is slightly greater than the thickness of the crossbeam body, ensuring that both ends of the bushing are flush with or slightly protrude from the surface of the body. This design effectively distributes the axial load applied by the bolts and prevents the carbon fiber layer from compressing under stress.

[0075] In another possible implementation, the outer periphery of the metal bushing 3 is designed with an annular groove filled with an epoxy resin matrix material. This design can further enhance the pull-out resistance of the bushing during the co-curing process, thereby improving its reliability under long-term vibration loads.

[0076] Understandably, the embedding position of the metal bushing 3 in the rear crossbeam body 1 must meet specific mechanical distribution requirements to ensure connection strength and uniform load distribution. For example, the metal bushing 3 is typically arranged at critical connection points of the crossbeam, such as the connection points with the vehicle body or other structural components, to ensure that these areas have sufficient tensile, shear, and compressive strength.

[0077] In this embodiment, the metal bushing 3 is integrally formed with the rear crossbeam body 1 through a co-curing process. As a result, a strong interface bond is formed between the bushing and the carbon fiber composite material, thereby avoiding slippage or loosening problems that may occur in traditional mechanical connections. This integrated design significantly improves the overall structural strength and service life of the crossbeam.

[0078] In some embodiments, the material and structural design of the metal bushing 3 can be adjusted according to different vehicle models or load conditions. For example, for vehicle models that need to withstand higher loads, a higher-strength titanium alloy can be selected as the bushing material, or the outer diameter of the bushing can be increased and the number of bushings or the bushing positions can be reasonably increased to improve the shear resistance of the embedded area.

[0079] It is worth noting that the arrangement and design of the metal bushing 3 can adapt to the usage requirements of different environments. For example, commercial vehicles operating in salt spray corrosion environments can further improve their durability by adding an anti-corrosion coating to the bushing surface; vehicles operating in high vibration environments can reduce stress concentration by optimizing the size and geometry of the bushing.

[0080] In this embodiment, the metal bushing 3 not only meets the mechanical performance requirements of bolted connections, but also achieves efficient production and structural performance optimization through synchronous molding processes with carbon fiber composite materials, providing reliable technical support for the lightweight and high-performance design of commercial vehicle crossbeams.

[0081] In summary, this invention achieves lightweight, high strength, and excellent fatigue performance in the rear crossbeam by employing a composite material body composed of carbon fiber woven fabric and an epoxy resin matrix, combined with a C-shaped rib plate 2 design and a pre-embedded metal bushing 3 structure. The rib plate 2, located at the right-angle bend of the crossbeam, enhances local strength and overall rigidity through integral molding, addressing the issue of large torsional deformation. The metal bushing 3 is cured synchronously with the main body, ensuring the reliability and durability of the bolted connection. Through precise material selection and design optimization, the overall process meets the requirements of use under complex load conditions, providing an efficient solution for lightweighting and structural performance improvement in commercial vehicles.

[0082] Please see the appendix Figure 2 Correspondingly, the present invention also provides a co-curing preparation process for ribbed carbon fiber composite beams for commercial vehicles, comprising the following steps:

[0083] S1. Mold preparation:

[0084] In this embodiment, the mold is designed as a modular structure, comprising four parts: upper and lower molds, and left and right molds. A small detachable module is also included to facilitate laying and molding operations. The mold's internal cavity is precisely customized according to the shape of the rear crossbeam, with a dedicated positioning structure in the rib area to ensure the rib laying accuracy.

[0085] As an alternative, to avoid defects on the surface of the finished beam, the inner surface of the mold is coated with a high-temperature resistant release agent and polished to a mirror finish to improve the smoothness and release performance of the mold surface. It should be noted that the mold is also equipped with multiple vacuum ports to facilitate effective removal of air bubbles during subsequent vacuuming operations.

[0086] S2, Rib positioning:

[0087] In this embodiment, carbon fiber prepreg is designed and cut according to the shape of the ribs, and then precisely laid into the designated positions of the ribs within the mold. When laying the ribs, carbon fiber prepreg in the 0° / 90° direction is preferentially used as the bottom layer material to provide basic stiffness.

[0088] Specifically, after the rib area is laid, a rolling tool is used to compact each layer of prepreg fabric, eliminating potential air bubbles and ensuring that the material adheres tightly to the inner wall of the mold. This process lays the foundation for the high-precision forming of the ribs and their integration with the main beam.

[0089] S3. Main paving:

[0090] After the ribs are laid, the carbon fiber prepreg is laid on the main body of the crossbeam. In this embodiment, the main body is laid using an alternating method of laying carbon fiber prepreg in the 0° / 90° and 45° / -45° directions until the designed thickness is achieved.

[0091] In one possible implementation, additional unidirectional prepreg is cut and used for reinforcement in the right-angle turning areas of the main beam. It should be noted that the application of unidirectional prepreg not only significantly improves the local strength of the turning area but also effectively mitigates stress concentration and extends the service life of the beam.

[0092] During the laying process, each layer of carbon fiber prepreg is compacted by using a special rolling tool to roll it from one end to the other along the fiber direction to ensure tight bonding between layers and no air bubbles.

[0093] When laying the prepreg, leave round holes in it, and pass the bushing through the round holes of each layer of prepreg. Multiple layers of prepreg will completely wrap the bushing.

[0094] S4. Bushing installation:

[0095] Before installation, the surface-roughened aluminum alloy bushing is placed in a predetermined position within the mold. For example, the bushing is secured with a weak adhesive to ensure it does not shift during subsequent installation. Before installing the main body, a circular hole is made in each layer of prepreg fabric during installation. The bushing passes through each hole and is completely wrapped during the installation of multiple layers of prepreg fabric.

[0096] Understandably, the outer circumferential surface of the metal bushing is designed with annular grooves, and the grooves are filled with epoxy resin matrix material to further improve its bonding performance with the carbon fiber layer.

[0097] S5, Vacuuming:

[0098] After the main body is laid in the lower mold of the mold, before closing the mold, a sealed cavity is created in the lower mold using adhesive strips, breathable felt, and a vacuum bag to enclose the unformed part. Then, the mold is evacuated using a vacuum pump, air pipe, and metal nozzle. In this embodiment, the vacuum level is controlled at -0.1 MPa, and the operation time is 10–15 minutes to ensure that air and bubbles inside the mold are completely eliminated. After vacuuming, the state of the preformed part is observed. Once it is confirmed that there are no bubbles or unevenness, the mold is closed and sealed.

[0099] Understandably, vacuuming is crucial for ensuring the quality of the interfacial bonding between carbon fiber layers and between carbon fiber and metal bushing, effectively preventing delamination or void defects in the finished product.

[0100] S6, Curing:

[0101] The curing process in this embodiment employs a multi-stage heating process to ensure that the epoxy resin matrix is ​​fully cross-linked during curing, while avoiding internal stress problems caused by excessively rapid temperature changes. The specific steps are as follows:

[0102] First stage: Increase the temperature from room temperature to the pre-curing temperature (60℃) at a rate of 2℃ / min and hold for 30 minutes. This stage is to reach the coating temperature, at which point the viscosity of the adhesive decreases and its fluidity increases, allowing the adhesive to move fully within the mold, eliminating internal pores and reducing surface adhesive deficiency.

[0103] Second stage: Increase the temperature from the pre-curing temperature to the final curing temperature (130℃-150℃) at a heating rate of 1℃ / min and hold for 1 to 2 hours to ensure complete cross-linking of the resin.

[0104] Third stage: After final curing, stop heating and allow the mold to cool slowly to room temperature with the equipment to avoid thermal stress caused by rapid cooling.

[0105] It should be noted that during the curing process, the pressure is maintained at 30 kg in the first stage and 100 kg in the second stage to further improve the interlayer bonding strength and ensure the dimensional accuracy of the final beam.

[0106] S7. Post-processing:

[0107] After curing is complete and the material has cooled to room temperature, the mold is removed and the beam components are post-processed.

[0108] The specific steps are as follows:

[0109] Trimming: Use high-precision cutting tools to trim the edges of the beam, removing burrs and excess material.

[0110] Polishing: Use sandpaper with a grit of 200 to 600 to polish the surface of the beam to improve the surface finish and eliminate potential defects.

[0111] Quality inspection: Defects such as bubbles and delamination inside the crossbeam are detected by ultrasonic testing or CT scanning. At the same time, mechanical tests such as bending strength and fatigue performance are carried out to ensure that the quality of the crossbeam meets the design requirements.

[0112] In this embodiment, the ribs, metal bushings, and rear crossbeam body are integrally formed using the aforementioned co-curing process, significantly improving the overall structural strength and service life of the crossbeam. The optimized layup sequence and curing parameters ensure the full utilization of the composite material's mechanical properties while greatly improving production efficiency, providing a reliable, high-performance, lightweight solution for the commercial vehicle sector.

[0113] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A ribbed crossbeam made of carbon fiber composite material for commercial vehicles, characterized in that, include: The main body of the rear crossbeam is made of prepreg fabric composed of carbon fiber woven fabric and epoxy resin matrix through a co-curing process; The rib plate is located at the right-angle turn of the rear crossbeam body and is integrally formed with the rear crossbeam body through a co-curing process. Metal bushings are embedded in the rear crossbeam body for use in assembling connecting bolts. The metal bushings and the rear crossbeam body are cured simultaneously to form a whole. The rib plate has a C-shaped structure, and the material of the rib plate is the same as that of the rear crossbeam body; The metal bushing is made of aluminum alloy and is fixed in the mold during installation by a positioning device, so that it is cured synchronously with the main body of the rear crossbeam.

2. The ribbed carbon fiber composite beam for commercial vehicles according to claim 1, characterized in that, The prepreg composed of carbon fiber woven fabric and epoxy resin matrix includes: 0° / 90° biaxial prepreg is used to provide flexural strength; 45° / -45° biaxial prepreg is used to provide shear resistance.

3. The ribbed crossbeam of carbon fiber composite material for commercial vehicles according to claim 2, characterized in that, The prepreg, composed of carbon fiber woven fabric and epoxy resin matrix, is laid alternately with different fiber directions to form a multi-layer composite material structure.

4. The ribbed crossbeam of carbon fiber composite material for commercial vehicles according to claim 3, characterized in that, Both the rib plate material and the rear crossbeam body are made of T400-12K carbon fiber prepreg.

5. The ribbed crossbeam made of carbon fiber composite material for commercial vehicles according to claim 1, characterized in that, The fiber mass content of the carbon fiber woven prepreg of the rear crossbeam body is 58% to 65%.

6. A co-curing process for preparing ribbed carbon fiber composite beams for commercial vehicles, used to prepare ribbed carbon fiber composite beams for commercial vehicles as described in any one of claims 1-5, characterized in that, Includes the following steps: Mold preparation: Design and manufacture an integral, modular mold, including upper and lower molds, left and right molds, and a release module; before laying, clean the mold surface and apply a release agent and release wax; Bushing installation: Place the aluminum alloy metal bushing at the predetermined position inside the mold and fix it with adhesive; Rib positioning: Cut carbon fiber prepreg according to the shape of the rib, lay it on the rib groove limit on the upper surface of the mold and compact it; Main body laying: Alternately lay 0° / 90° and 45° / -45° carbon fiber prepreg to the designed thickness, and lay unidirectional prepreg at right angles for reinforcement; Vacuuming: Performing vacuum treatment to remove air bubbles from the layup; Curing: Place the assembled mold into a preheated 60℃ molding press and cure it according to the preset temperature, pressure and time parameters; Post-processing: After curing, cool to room temperature, demold, and then trim and polish the beam components to ensure surface quality and dimensional accuracy.

7. The co-curing preparation process for ribbed carbon fiber composite beams for commercial vehicles according to claim 6, characterized in that, The curing step is performed at a temperature of 130℃ to 150℃, a pressure of 30 to 100 kg, and a curing time of 1 to 2 hours.

8. The co-curing preparation process of ribbed carbon fiber composite beams for commercial vehicles according to claim 6, characterized in that, The curing step employs a multi-stage heating process, including: In the first stage, the temperature is increased from room temperature to the pre-curing temperature at a rate of 2℃ / min. In the second stage, the resin is kept at the pre-curing temperature for 1 to 2 hours to ensure complete cross-linking. In the third stage, the temperature is increased to the final curing temperature at a heating rate of 1℃ / min.

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