Frame type tubular part block combination design and manufacturing method based on carbon fiber winding reinforcement

Abstract

The invention provides a block combination design and manufacturing method based on carbon fiber winding reinforcement for frame type pipe fittings, and relates to the technical field of lightweight structure design and manufacturing. Pipe profiles produced on a large scale are used as basic function modules, and through topological structure optimization and functional structure splitting of the frame type hollow pipe fittings, the frame type hollow pipe fittings are subjected to block combination design and manufacturing; the framework type pipe fitting is divided into standardized pipe section bar modules, the standardized pipe section bar modules are combined into an integral structure of the framework type pipe fitting through a simple connecting process, and then differential enhancement and fine regulation and control of the performance of different parts of the pipe fitting are achieved through a pre-designed carbon fiber winding process. According to the method, the manufacturing difficulty of integrated forming of the hollow thin-wall complex structure is avoided, a traditional welding method is replaced by combining a simple connecting process with carbon fiber winding, and the process problem of traditional welding is avoided. Automatic scale production can be achieved, and compared with an existing forming process, the process difficulty and the manufacturing cost are lower.

Description

Technical Field

[0001] The present invention relates to the technical field of lightweight structure design and manufacturing, and in particular to a block combination design and manufacturing method of a frame-type tubular component based on carbon fiber winding reinforcement. Background Art

[0002] In response to the current challenges of environmental pollution and the energy crisis, lightweighting has become an inevitable trend in sectors such as automotive and rail transit. With the rapid development of new energy vehicles, especially, reducing vehicle weight can significantly reduce energy consumption and increase range, making the pursuit of lightweighting even more urgent. Simultaneously, the demand for lightweighting continues to escalate in aerospace, engineering machinery, future humanoid robots, and the low-altitude economy. Weight reduction and optimization of structural mass in the aerospace sector has a significant multiplier effect on improving transport efficiency. Weight reduction in humanoid robots can effectively improve endurance, enhance motion performance, reduce component loads, and improve safety. In the low-altitude economy, weight reduction is crucial: increasing range, increasing payload, improving flight performance, and reducing operating costs.

[0003] Existing weight reduction methods primarily rely on lightweight materials and structural optimization. Magnesium and its alloys are the lowest-density lightweight metal structural materials (1.8 g / cm³), offering high specific strength and stiffness, as well as excellent damping and heat dissipation properties. They are increasingly being used in the automotive, aerospace, and consumer electronics sectors. Carbon fiber-reinforced composites (CFRPs), with a density similar to that of magnesium alloys, possess high specific strength and stiffness. Furthermore, through various layup and winding methods, they can be combined with metal materials to form composites, offering exceptional design flexibility. They are widely used in aerospace, automotive, sporting goods, and low-altitude economy sectors. Another approach to weight reduction is hollow or thin-walled structural designs, which meet strength requirements while effectively reducing weight. Hollow tubes, in particular, can achieve a 30%-50% weight reduction while maintaining excellent mechanical properties and energy absorption characteristics. Furthermore, through computer-aided design, structural topology optimization can be performed to remove material from non-load-bearing or low-load-bearing areas, achieving weight reduction without compromising structural performance. This has become a key lightweight design method in various fields.

[0004] Frame-type hollow tubular components made of lightweight materials offer great potential for lightweight applications, due to their dual advantages of integrated material and structural lightweighting. Applications include wings, fuselage frames, automotive subframes, body frames, and bumpers. However, these hollow tubular components are inherently complex, and even after topological optimization, their individual components have varying load-bearing requirements. This further complicates the overall shape of the component, making integrated forming (casting, stamping, welding, etc.) difficult and costly. While 3D printing technology can directly produce complex components based on design models, achieving lightweight structural design while conserving materials, it comes at a high cost and cannot meet the demands of large-scale production. Summary of the Invention

[0005] To address the technical challenges in forming and manufacturing hollow tubular components for frameworks, the present invention proposes a block-by-block design and manufacturing method for framework tubular components based on carbon fiber winding reinforcement. This method primarily includes the following steps: (1) For the target product of frame components, the initial three-dimensional model of the product is first established and the optimizable area is delineated. By applying actual working loads and constraints, minimizing mass or maximizing stiffness is taken as the optimization goal. Combined with stress, displacement and manufacturing process constraints, the SIMP algorithm is used to iteratively calculate the material distribution. The high-density area is extracted as the main stress transfer path and reconstructed into a hollow tubular structure. Finally, the optimization result is split into standardized tube profile modules. The design feasibility is ensured through static analysis and performance verification. After the above-mentioned topology optimization algorithm, a lightweight hollow tube structure is obtained, forming a topological configuration that takes into account both mechanical properties and material efficiency. (2) The frame-type hollow tubular structure optimized in step (1) is divided into different functional modules according to the cross-sectional shape and size of different parts and the service performance requirements. Each functional module is simplified into a tube profile of a certain specification. The modules are interconnected according to the topological configuration to form the overall structure of the frame-type tubular part. (3) For the different functional modules in step (2), select the tube profile material that meets the function and minimize the difference in tube profile specifications to facilitate combination and connection; (4) The functional modules are connected and combined to form the overall structure of the frame-type tubular parts; when connecting and combining, the connection methods such as butt joint, overlap joint, L-type connection, T-type connection or cross-type connection are selected according to the geometric shape, relative position and load requirements of the functional modules at that part; (5) Determine the mapping relationship between carbon fiber winding process parameters and pipe performance enhancement based on the test results, and design the process parameters in advance based on the load required by the pipe; the process parameters include: fiber winding angle and number of layers; (6) The overall structure of the frame-type tubular part connected in step (5) is fed along the axis of the tubular part, and carbon fiber is continuously wound around the outer contour of the tubular part. The connection part is reinforced using pre-designed carbon fiber winding process parameters according to the type of connection structure, thereby achieving performance enhancement and fine control of the connection part of the tubular part.

[0006] Preferably, the material of the tube profile in step (3) is mainly selected from lightweight alloy materials, and the functional modules with high requirements for local performance are selected from high-performance alloy tube profiles. Preferably, in step (4), the functional modules are connected and combined by gluing.

[0007] Preferably, in step (6), a "geodesic-non-geodesic" collaborative winding method is adopted for the T-shaped connection part: the straight pipe parts of the main pipe and the branch pipe adopt a geodesic winding trajectory, which utilizes the stability of the natural path of the fiber and the tension self-balancing effect of the square pipe corners to effectively suppress the slip phenomenon; while the transition zone adopts a non-geodesic trajectory winding method, which maintains the stability of the fiber by changing the angle with the help of friction and the adhesion of epoxy resin.

[0008] Preferably, in step (6), the shortest distance between two points (i.e., the geodesic method) is used to wind the overlapped connection part: the carbon fiber bundle is vertically connected to a point on the other side of the overlapped part of the overlapped tubular part along the shortest distance from a random point at one end of the overlapped part of the overlapped tubular part, and the cycle is repeated to complete the carbon fiber reinforcement work of the overlapped part of the overlapped tubular part.

[0009] Preferably, in step (6), the non-geodesic winding method is still used for the L-shaped link structure: the straight pipe section is wound and reinforced using the geodesic method, and then multiple sets of winding trajectories with different angles (i.e., the non-geodesic method) are used at the right-angle position to increase the fit of the fiber and cover the right-angle position of the pipe. After completing the winding of the right-angle position, the other straight pipe section is transitioned to continue winding using the geodesic method, and this process is repeated to complete the winding reinforcement of the L-shaped connection structure.

[0010] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses large-scale produced tube profiles as the basic functional module, which is combined into a frame-type tube-shaped integral structure through a simple connection process. Then, through a pre-designed carbon fiber winding process, the performance of different parts of the tube-shaped parts is differentiated and finely controlled. The technology of the present invention avoids the manufacturing difficulty of integrated forming of hollow thin-walled complex structures through block combination. It replaces traditional welding methods with simple connection processes combined with carbon fiber winding, thus avoiding the process problems of traditional welding. It can achieve automated large-scale production, and compared with existing forming processes, the process difficulty and manufacturing cost are lower; (2) The frame-type tubular parts involved in the present invention integrate numerous lightweight elements such as carbon fiber, lightweight alloy, hollow thin-walled tubes, and topological configurations, achieving the combined advantages of material lightweighting, structural lightweighting, and topological optimization, thereby maximizing the lightweight design and manufacturing of products. Compared with current lightweight products, it has greater lightweight advantages; (3) The present invention integrates product design, topology optimization and forming technology. Frame-type tubular parts first embody the product design and topology optimization ideas through block-type modular design. On this basis, the designability of fiber winding is fully utilized, and the performance of different parts is enhanced and finely controlled through carbon fiber winding process design. Unlike traditional forming processes, the technology of the present invention integrates product concepts into forming processes and manufacturing in real time, presenting customized and intelligent processing advantages; (4) Carbon fiber winding provides outer protection for the tube profile, eliminating the need for additional surface protection treatment and solving the problem of alloy corrosion. If the tube profiles are bonded together, the insulating effect of the polymer material avoids the galvanic corrosion problem at the traditional welding or screwing parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the automobile subframe product and its block design according to Example 1; Figure 2 Schematic diagram of the overall structure of the automobile subframe and its component modules of Example 1; Figure 3 Comparison diagram of straight pipe specimens with different numbers of winding layers before and after bending under three-point bending conditions; Figure 4 It is a T-shaped connection structure in the overall structure of the subframe; Figure 5 This is a schematic diagram of the winding trajectory of the T-type connection structure; Figure 6 This is a comparison diagram of the T-type connection structure before and after compression; Figure 7 Comparison of compression mechanical properties of T-type connection structure; Figure 8 It is a lap-type connection structure in the overall structure of the subframe; Figure 9 It is a schematic diagram of the winding trajectory of the overlapped connection structure; Figure 10 This is a comparison diagram of the overlapped connection structure before and after compression and shearing; Figure 11 Comparison of compression and shear mechanical properties of lap joint structures; Figure 12 L-shaped connection structure in the overall structure of the subframe; Figure 13 This is a schematic diagram of the winding trajectory of the L-shaped connection structure; Figure 14 This is a comparison of the L-shaped connection structure before and after bending; Figure 15 Comparison of bending mechanical properties of L-shaped connection structure; Figure 16 This is a finished winding product diagram of a block combination design of a subframe tubular component reinforced with carbon fiber winding. DETAILED DESCRIPTION

[0012] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. The present invention will be further described below in conjunction with specific examples and drawings.

[0013] Example 1 Figure 1 The automotive subframe is a hollow, thin-walled, frame-like component with varying shapes and dimensions to meet the varying load-bearing requirements of each area. The complex overall shape of the component makes it extremely difficult to form it in one piece through processes like casting or stamping. Therefore, to simplify the molding process, the subframe is divided into blocks, with different colors representing different parts. Each block is molded separately (typically using low-pressure casting) and then assembled through welding to form the entire subframe. However, while this block-by-block welding process reduces the difficulty of integrated component molding, it adds additional welding steps and auxiliary tooling, resulting in a cumbersome process, reduced molding efficiency, and high manufacturing costs.

[0014] To address the current technical challenges in forming and manufacturing automotive subframes, this paper takes the block-by-block design and manufacturing of an AZ31 magnesium alloy subframe reinforced with carbon fiber winding as an example. The main steps are as follows: (1) For the subframe product, the initial three-dimensional model of the subframe is first established and the optimizable area is delineated. By applying actual working loads (vertical force, vibration load) and constraints (fixed installation point), the optimization goal is to minimize mass or maximize stiffness. Combined with stress, displacement and manufacturing process constraints (such as wall thickness ≥ 2 mm), the SIMP algorithm is used to iteratively calculate the material distribution. The high-density area is extracted as the main stress transfer path and reconstructed into a hollow tubular structure. Finally, the optimization results are split into standardized tube profile modules (such as straight tubes and curved tubes). The design feasibility is ensured through static analysis and performance verification (lightweight rate, stress distribution uniformity). After the above-mentioned topology optimization algorithm, a lightweight subframe hollow tubular structure is obtained, forming a topological configuration that takes into account both mechanical properties and material efficiency. (2) The automobile subframe structure optimized in step (1) is divided into different functional modules according to the cross-sectional shape, size and performance requirements of different parts. Each functional module is simplified into a tube profile of a certain specification. The modules are interconnected according to the topological configuration to form the overall structure of the automobile subframe tube. Figure 2 As shown; (3) For different functional modules in step (2), select tube profiles that meet the basic functions, with AZ31 magnesium alloy as the main material. For casing modules with high requirements for local service performance (such as bearing strength, fatigue strength, wear resistance, etc.), high-strength steel tube profiles can be selected, and the differences in tube profile specifications should be minimized to facilitate combination and connection; (4) Each functional module is connected and combined by gluing to form a closed subframe tubular structure. The connection structure can be T-type, overlap, L-type, etc. according to the geometric shape and relative position of the functional module and the load requirements at that location; (5) Further, the sub-frame tubular component integral structure connected in step (4) is fed along the axial path of the tubular component, and carbon fiber is continuously wound on the outer contour of the tubular component. By utilizing the designability characteristics of carbon fiber winding, the mapping relationship between carbon fiber winding process parameters and the performance enhancement of the tubular component is determined according to the test results, and the process parameters are designed in advance according to the load required to be borne by the tubular component; the process parameters include: fiber winding angle and number of layers; To achieve differentiated enhancement and fine control of the performance of different parts of the pipe parts based on the original pipe profile. Figure 3 The following are actual photos of magnesium alloy tubes with different numbers of carbon fiber winding layers before and after the three-point bending performance test. Table 1 shows the bending performance and energy absorption characteristics corresponding to different carbon fiber winding angles.

[0015] Table 1 (6) For the connection parts between the functional modules of the subframe tubular parts, the pre-designed carbon fiber winding process is used to reinforce the connection parts according to the type of connection structure, so as to achieve performance enhancement and fine control of the connection parts of the tubular parts.

[0016] in Figure 4 A T-type connection structure is used. For the T-type connection part, a "geodesic-non-geodesic" collaborative winding method is used: the straight pipe parts of the main pipe and branch pipe adopt a geodesic winding trajectory, which can effectively suppress the slip phenomenon by utilizing the stability of the natural path of the fiber and the tension self-balancing effect of the square pipe corners; while the transition area adopts a non-geodesic trajectory winding method, which maintains the fiber stability by changing the angle and relying on friction and epoxy resin adhesion. In specific implementation, Figure 5 As shown; and the compression test is carried out on the T-shaped connection part after winding, and the comparison before and after compression is shown in the figure below. Figure 6 As shown, the performance comparison is Figure 7 As shown; Figure 8The lap joint structure is shown. The lap joint structure uses the shortest distance between two points (i.e., the geodesic method) for winding: starting from a random point at one end of the lap joint of the lap joint tubular piece, the carbon fiber bundle is vertically connected to the point on the other side along the shortest distance, and the cycle is repeated to complete the carbon fiber reinforcement work of the lap joint of the lap joint tubular piece. In specific implementation, Figure 9 As shown; and the lap joint after winding is subjected to compression shear test, and the comparison before and after compression shear is shown in the figure below. Figure 10 As shown, the performance comparison is Figure 11 As shown; Figure 12 As shown, an L-shaped connection structure is used. For L-shaped connection structures, non-geodesic winding methods can still be used: the straight pipe section is wound and reinforced using the geodesic method, and then multiple sets of winding trajectories with different angles (i.e., non-geodesic methods) are used at the right angles to increase the fiber's fit and cover the right angles of the pipe. After completing the winding of the right angles, the other straight pipe section is wound using the geodesic method. This process is repeated to complete the winding reinforcement of the L-shaped connection structure. In specific implementation, Figure 13 As shown; and the L-shaped connection part after winding is subjected to bending test, and the comparison before and after bending is shown in Figure 14 As shown, the performance comparison is Figure 15 As shown; (7) According to the carbon fiber winding process plan in step (6), a collaborative path for carbon fiber winding and tubular component axis feeding is generated to facilitate the automated winding of carbon fiber for frame tubular components. The finished winding product of the subframe tubular component based on the block combination design of carbon fiber winding reinforcement is shown in the figure below. Figure 16 shown.

[0017] Current automotive subframes produced using integrated molding or block-welding processes suffer from high mold development costs, complex processes, and difficulty achieving lightweighting. However, the closed subframe, achieved through a block-based design and localized carbon fiber reinforcement, employs this innovative design. This block-based design and localized reinforcements achieve multi-dimensional efficiency gains and increase the overall lightweighting rate by 40% to 60%. Comparative analysis demonstrates that the method proposed in this invention offers greater reliability in achieving cost savings while maintaining strength in the lightweighting field.

Claims

1. A method for designing and manufacturing a block-by-block assembly of a frame-type tubular component based on carbon fiber winding reinforcement, characterized in that: The steps of this method are as follows: (1) For the target product of frame components, the initial three-dimensional model of the product is first established and the optimizable area is delineated. By applying actual working loads and constraints, minimizing mass or maximizing stiffness is taken as the optimization goal. Combined with stress, displacement and manufacturing process constraints, the SIMP algorithm is used to iteratively calculate the material distribution. The high-density area is extracted as the main stress transfer path and reconstructed into a hollow tubular structure. Finally, the optimization result is split into standardized tube profile modules. The design feasibility is ensured through static analysis and performance verification. After the above-mentioned topology optimization algorithm, a lightweight hollow tube structure is obtained, forming a topological configuration that takes into account both mechanical properties and material efficiency. (2) The frame-type hollow tubular structure optimized in step (1) is divided into different functional modules according to the cross-sectional shape and size of different parts and the service performance requirements. Each functional module is simplified into a tube profile of a certain specification. The modules are interconnected according to the topological configuration to form the overall structure of the frame-type tubular part. (3) For the different functional modules in step (2), select the tube profile material that meets the function and minimize the difference in tube profile specifications to facilitate combination and connection; (4) The functional modules are connected and combined to form the overall structure of the frame-type tubular parts; when connecting and combining, the connection methods such as butt joint, overlap joint, L-type connection, T-type connection or cross-type connection are selected according to the geometric shape, relative position and load requirements of the functional modules at that part; (5) Determine the mapping relationship between carbon fiber winding process parameters and pipe performance enhancement based on the test results, and design the process parameters in advance based on the load required by the pipe; The process parameters include: fiber winding angle and number of layers; (6) The overall structure of the frame-type tubular part connected in step (5) is fed along the axis of the tubular part, and carbon fiber is continuously wound around the outer contour of the tubular part. The connection part is reinforced using pre-designed carbon fiber winding process parameters according to the type of connection structure, thereby achieving performance enhancement and fine control of the connection part of the tubular part.

2. The method for designing and manufacturing a frame-type tubular component based on carbon fiber winding reinforcement according to claim 1 is characterized in that: In step (3), the material of the tube profile is mainly lightweight alloy material, and high-performance alloy tube profile is used for functional modules with high requirements for local service performance.

3. The method for designing and manufacturing a frame-type tubular component based on carbon fiber winding reinforcement according to claim 1 is characterized in that: In step (4), the functional modules are connected and combined by gluing.

4. The method for designing and manufacturing a frame-type tubular component based on carbon fiber winding reinforcement according to claim 1 is characterized in that: In step (6), the "geodesic-non-geodesic" collaborative winding method is used for the T-shaped connection part: the straight pipe parts of the main pipe and the branch pipe adopt the geodesic winding trajectory, which can effectively suppress the slip phenomenon by utilizing the stability of the natural path of the fiber and the tension self-balancing effect of the square pipe corners; while the transition zone adopts the non-geodesic trajectory winding method, which maintains the stability of the fiber by changing the angle with the help of friction and the adhesion of epoxy resin.

5. The method for designing and manufacturing a frame-type tubular component based on carbon fiber winding reinforcement according to claim 1 is characterized in that: In step (6), the shortest distance between two points is used to wrap the overlapping connection part: the carbon fiber bundle is vertically connected from a random point at one end of the overlapping part of the overlapping connection tubular part to a point on the other side along the shortest distance, and the cycle is repeated to complete the carbon fiber reinforcement work of the overlapping part of the overlapping connection tubular part.

6. The method for designing and manufacturing a frame-type tubular component based on carbon fiber winding reinforcement according to claim 1 is characterized in that: In step (6), the non-geodesic winding method is still used for the L-shaped link structure: the straight pipe section is wound and reinforced using the geodesic method, and then multiple sets of winding trajectories with different angles are used at the right-angle position to increase the fit of the fiber and cover the right-angle position of the pipe. After completing the winding of the right-angle position, the transition is made to the other straight pipe section and the geodesic method is used to continue winding. This process is repeated to complete the winding reinforcement of the L-shaped connection structure.

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