A topologically optimized CFRP-aluminum alloy sandwich control arm and a manufacturing method thereof

Abstract

This invention discloses a topology-optimized CFRP-aluminum alloy sandwich control arm and its manufacturing method, belonging to the field of lightweight automotive chassis structural design technology. Addressing the problems of heavy weight and insufficient lightweighting of traditional metal control arms, this control arm employs a sandwich structure consisting of two layers of carbon fiber reinforced composite (CFRP) panels and an intermediate aluminum alloy core layer. Optimal rib distribution within the core layer is obtained through topology optimization, balancing structural stiffness and weight control. The carbon fiber panels use 3K plain weave prepreg with 16 layers laid at [0° / 45° / -45° / 90°] layup angles. The aluminum alloy core layer is CNC machined to form a topology-optimized rib structure, which is then assembled with the panels using a glue-screw hybrid connection process. Compared to traditional metal control arms, this invention reduces weight by approximately 46.6% while meeting mechanical performance requirements, making it suitable for new energy vehicles and lightweight vehicle platforms.

Description

Technical Field

[0001] This invention relates to the field of lightweight structure design technology for automotive chassis, specifically to a CFRP-aluminum alloy sandwich control arm with topology optimization design and its manufacturing method. Background Technology

[0002] As the automotive industry moves towards energy conservation, emission reduction, and performance optimization, the demand for lightweight vehicle chassis structures is becoming increasingly significant. The control arm is a key component in the suspension system that transmits force and guides tire movement; its quality and mechanical properties directly affect the vehicle's fuel economy, handling stability, and ride comfort.

[0003] Traditional control arms are typically made of high-strength steel or aluminum alloy, which are simple in structure and low in manufacturing cost. However, due to their high density, they are difficult to meet the stringent requirements of "lightweight and high strength" for new energy vehicles and high-performance vehicles.

[0004] Carbon fiber reinforced polymer (CFRP) composites possess characteristics such as low density, high specific strength, and long fatigue life, and have been widely used in high-end vehicle bodies, body panels, and other components. However, controlling the overall stiffness of CFRP structures is quite complex, making it difficult to withstand multi-directional coupled loads independently.

[0005] Sandwich structures, as a typical lightweight solution balancing structural performance and mass, combine high-strength panel materials with lightweight core materials, thus achieving both out-of-plane stability and overall stiffness. However, most current sandwich structure designs rely on manual experience, resulting in crude structural layouts that fail to balance dynamic performance, manufacturing costs, and connection stability. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a topology-optimized CFRP-aluminum alloy sandwich control arm and its manufacturing method. The core layer structure is derived from topology optimization solutions based on the control arm's operating conditions. Under multiple performance constraints, the optimal aluminum alloy rib distribution is automatically generated. A hybrid glue-screw connection process achieves stable integration of the carbon fiber reinforced composite panel and the aluminum alloy core layer. This constructs a lightweight, high-strength control arm structure and provides its manufacturing method, meeting the demands of current new energy vehicles and lightweight vehicle platforms.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A topology-optimized CFRP-aluminum alloy sandwich control arm is constructed by sequentially connecting an upper carbon fiber reinforced composite panel, an aluminum alloy sandwich layer, and a lower carbon fiber reinforced composite panel from top to bottom. The aluminum alloy core layer of the sandwich control arm has three ends, with two ends used for bushing installation connections and the outer end used for ball joint connections.

[0009] The carbon fiber reinforced composite panel is made of carbon fiber and thermosetting epoxy resin through compression molding, with a thickness of approximately 4 mm; the aluminum alloy core layer has a thickness of 24 mm, and the ribs have a thickness of 2 mm, which are made by precision CNC machining; the carbon fiber reinforced composite panel and the aluminum alloy core layer are connected by adhesive and screw to form a whole.

[0010] The adhesive-screw hybrid connection should involve drilling six holes at the bolt connection points of both the aluminum alloy core layer and the carbon fiber reinforced composite panel, and connecting them with bolts. Simultaneously, adhesive should be filled between the carbon fiber reinforced composite panel and the aluminum alloy core layer.

[0011] A method for manufacturing a CFRP-aluminum alloy sandwich control arm with topology optimization design includes the following steps:

[0012] S1: Construct a topology optimization model for the sandwich control arm; take the minimum weighted strain energy under two stiffness conditions as the optimization objective, and take the unit density in the thick plate region of the aluminum alloy core layer of the sandwich control arm as the design variable. By optimizing the topology optimization model, the optimized design value of the aluminum alloy core layer unit density is obtained, and the result is represented as a two-dimensional topology pattern.

[0013] S2: In the two-dimensional topological pattern obtained based on S1, the element density in the light-colored region tends to be 1, and these are the main structures to be retained; the element density in the dark-colored region tends to be 0, and these are regions that can be deleted; while the transition part between 0 and 1 can be selected according to design requirements. Taking an element density threshold of 0.5, and comprehensively considering the processing and manufacturing requirements, the model is reconstructed based on the topology optimization results.

[0014] S3: Based on the aluminum alloy core layer topology optimization structure obtained in S2, a three-dimensional model of the aluminum alloy core layer of the sandwich control arm is constructed and manufactured by precision CNC machining.

[0015] S4: Prepare the carbon fiber plain weave prepreg using a thermosetting epoxy resin matrix. Place the plain weave prepreg in an aluminum mold and lay it in a [0° / 45° / -45° / 90°]4 sequence, with a single layer thickness of 0.25mm, for a total of 16 layers. Seal it with release cloth and a breathable cotton layer, and pre-compress it in a vacuum bag.

[0016] S5: High temperature curing, using the following temperature and pressure curve: First stage: 80℃, -0.96MPa, hold for 0.5 hours; Second stage: 120℃, -0.96MPa, hold for 2 hours; Demold after natural cooling to room temperature.

[0017] S6: Cut the molded carbon fiber reinforced composite panel to the core layer design outline, trim the flash, polish the surface, and drill bolt holes at the connection position. Align and assemble the aluminum alloy core layer with the CFR P panel structure, apply adhesive at the interface, and tighten the high-strength bolts. After curing, an integral structure is formed.

[0018] In step S4, 3K plain weave prepreg carbon fiber is used for molding.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The total mass of the carbon fiber composite-aluminum alloy core control arm is reduced by about 46.6% compared with the traditional steel structure, achieving vehicle lightweighting. The optimal rib distribution layout of the aluminum alloy core layer is designed through topology optimization, taking into account dynamic performance, manufacturing cost and connection stability. Attached Figure Description

[0021] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0022] Figure 1 This is the aluminum alloy core layer of the sandwich control arm after topology optimization according to the present invention;

[0023] Figure 2 The aluminum alloy core layer of the sandwich control arm of this invention;

[0024] Figure 3 This is a schematic diagram of the structure of the sandwich control arm of the present invention;

[0025] Figure 4 This is an exploded view of the sandwich control arm of the present invention;

[0026] Figure 5 This is a schematic diagram of the manufacturing process of the sandwich control arm provided by the present invention;

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Clamping control arm body;

[0029] 2. Carbon fiber panel for sandwich control arm;

[0030] 3. Aluminum alloy core layer of the sandwich control arm;

[0031] 4-6. End of aluminum alloy core layer of sandwich control arm. Detailed Implementation

[0032] To further illustrate the technical content of the present invention, the sandwich structure control arm of the present invention will be described in detail below with reference to the accompanying drawings and specific structural dimensions.

[0033] like Figure 3As shown, a CFRP-aluminum alloy sandwich control arm (1) with topology optimization design is presented. The control arm is a sandwich composite structure consisting of an aluminum alloy core layer (3) and upper and lower carbon fiber composite panels (2). Connecting structural components (4) and (6) are provided at both ends of the aluminum alloy core material, which are connected to the subframe through front and rear bushings. A ball joint connector (5) is provided at the outer end, which is connected to the steering knuckle through a ball joint. The whole structure is a three-point suspension connection structure.

[0034] The carbon fiber composite panel (2) is a laminated structure, which is made of multiple layers of 3K plain weave carbon fiber prepreg. The resin system is a thermosetting epoxy resin. The layup angles are arranged symmetrically as follows: [0° / 45° / -45° / 90°]4. The thickness of a single layer is 0.25 mm, and a total of 16 layers are laid with a total thickness of 4 mm.

[0035] The aluminum alloy core material (3) is made of 6061-T6 aluminum material by precision CNC machining. The thickness of the aluminum alloy core layer is 24mm, and the thickness of the rib is 2mm. Bolt holes are drilled at the connection position to facilitate docking and installation with the carbon fiber composite panel. The bolt size is M6, and the quantity is 2 bolts per end.

[0036] The manufacturing method of the sandwich structure control arm of the present invention is as follows, and the specific steps are as follows:

[0037] S1: Establishment of the topological pattern of the core layer of the two-dimensional control arm

[0038] The two-dimensional design domain of the control arm core layer is determined; the physical properties of the core layer material are determined, and a topology optimization model of the control arm core layer is constructed and input into the topology optimization software; the same loading conditions as the steel control arm are adopted, and the element density in the thick plate region of the core layer (excluding the three ends) is used as the design variable. The optimization objective is to minimize the weighted strain energy under the two stiffness conditions. Through the above topology optimization model, the element density of the control arm core layer is optimized, and the optimized aluminum alloy core layer element density design value is obtained. The result represents the two-dimensional topological pattern of the control arm core layer.

[0039] S2: Establishment of the 3D model of the core layer of the control arm

[0040] Based on the two-dimensional topological pattern obtained in S1, the element density in the light-colored areas tends to be 1, representing the main retained structure; the element density in the dark-colored areas tends to be 0, representing areas that can be deleted; and the transition area between 0 and 1 can be discarded according to design requirements. Taking an element density threshold of 0.5, the topology-optimized structure of the aluminum core layer is obtained. From the optimization results, the longitudinally and laterally distributed rib structures on the outer and inner sides of the core layer are the main retained structures, which can reduce the core layer mass while ensuring the performance of the control arm. Considering the processing and manufacturing requirements, the model is reconstructed based on the topology optimization results to obtain the topology-optimized structure of the aluminum alloy core layer. A three-dimensional model of the aluminum alloy core layer with reinforcing ribs and three ends is formed by extrusion and cutting using 3D modeling software such as SolidWorks.

[0041] S3: Based on S2, a three-dimensional model of the aluminum alloy core layer of the sandwich control arm is obtained, wherein the aluminum alloy core layer is 24mm thick and the rib is 2mm thick, and it is manufactured by precision CNC machining.

[0042] S4: 3K carbon fiber prepreg is used, employing a thermosetting epoxy matrix. It is manufactured in layers with symmetrically arranged layup angles of [0° / 45° / -45° / 90°]4. Each layer is 0.25mm thick, with a total of 16 layers and a total thickness of 4mm. It is encapsulated with release fabric and breathable cotton layers and pre-compressed in a vacuum bag. The entire layup is then placed in a hot press mold, ensuring continuous rounded corners and no overlaps or misalignments.

[0043] S5: Place the above preform into a hot press mold and apply the following temperature and pressure curve: First stage: 80℃, -0.96MPa, pressure holding for 0.5 hours (preheating and venting); Second stage: heat up to 120℃, -0.96MPa, constant temperature curing for 2 hours; after the mold cools to room temperature, demold to obtain a carbon fiber reinforced composite panel.

[0044] S6: Cut the molded carbon fiber reinforced composite panel to the core layer design outline, trim the flash, and polish the surface; drill M6 bolt through holes at the corresponding positions at the connection ends; after aligning the aluminum alloy core layer with the carbon fiber reinforced composite panel, apply epoxy structural adhesive, insert the bolts, and tighten the nuts; after the adhesive has cured for 24 hours, the connection assembly is completed.

[0045] This invention utilizes a sandwich structure control arm composed of a carbon fiber reinforced composite panel and an aluminum alloy core. Through topology optimization, the optimal rib distribution of the aluminum alloy core layer is designed, resulting in a lightweight, high-strength control arm structure with excellent vibration damping performance. The entire control arm weighs approximately 1.426 kg, representing a 46.6% weight reduction compared to the original steel control arm. This achieves a balance between lightweight design and high performance, making it suitable for the chassis systems of new energy vehicles and high-performance passenger cars.

[0046] The above embodiments are merely one of the preferred embodiments of the present invention. Any modifications, substitutions, and equivalent changes made by those skilled in the art to the structure, materials, and connection methods without departing from the principles of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method of manufacturing a topologically optimized design of a CFRP-aluminum alloy sandwich control arm, characterized in that, Includes the following steps: S1: Construct a topology optimization model for the sandwich control arm, with the minimum weighted strain energy under two stiffness conditions as the optimization objective. The element density within the thick plate region of the aluminum alloy sandwich layer of the sandwich control arm is used as the design variable. The optimized topology optimization model yields the optimized element density design value for the aluminum alloy sandwich layer, represented as a two-dimensional topological pattern. S2: In the two-dimensional topological pattern obtained in S1, the element density in the light-colored region tends to 1 and is the main retained structure; the element density in the dark-colored region tends to 0 and is the region that can be deleted; the transition portion between 0 and 1 can be selected according to design requirements. S3: Based on the aluminum alloy sandwich layer topology optimization structure obtained in S2, construct a three-dimensional model of the aluminum alloy sandwich layer of the sandwich control arm and fabricate it using precision CNC machining. S4: Prepare carbon fiber plain weave prepreg and select thermosetting... Epoxy resin matrix; Plain prepreg is placed in an aluminum mold and laid in the order of [0° / 45° / -45° / 90°]4, with a single layer thickness of 0.25mm, for a total of 16 layers; Encapsulated with release cloth and breathable cotton layer, and pre-pressed in a vacuum bag; S5: High temperature curing, using the following temperature and pressure curve: First stage: 80°C, -0.96MPa, hold for 0.5 hours; Second stage: 120°C, -0.96MPa, hold for 2 hours; Demolding after natural cooling to room temperature; S6: Cut the molded carbon fiber reinforced composite panel to the design outline of the sandwich layer, trim the flash, grind the surface, and drill bolt holes at the connection position. Align and assemble the aluminum alloy sandwich layer with the CFRP panel structure, apply adhesive at the interface, and tighten the high-strength bolts. After curing, an integral structure is formed; The CFRP-aluminum alloy sandwich control arm with topology optimization design is characterized by being composed of an upper carbon fiber reinforced composite panel, an aluminum alloy sandwich layer, and a lower carbon fiber reinforced composite panel connected sequentially from top to bottom; the structure of the aluminum alloy sandwich layer is derived from the topology optimization solution of the control arm's working conditions, automatically generating the optimal aluminum alloy rib distribution layout under multiple performance constraints; the carbon fiber reinforced composite panel and the aluminum alloy sandwich layer are connected as a whole by a glue-screw hybrid connection.

2. The manufacturing method of a topologically optimized CFRP-aluminum sandwich control arm according to claim 1, characterized in that In step S4, 3K plain weave prepreg carbon fiber is used for molding.

3. The manufacturing method of a CFRP-aluminum alloy sandwich control arm with topology optimization design according to claim 1, characterized in that, The aluminum alloy sandwich layer is made of 6061-T6 aluminum material through precision CNC machining.

4. The manufacturing method of a CFRP-aluminum alloy sandwich control arm with topology optimization design according to claim 1, characterized in that, The glue-screw hybrid connection should have holes drilled at the bolt connection points of the aluminum alloy sandwich layer and the carbon fiber reinforced composite panel, with a total of 6 holes. M6 bolt through holes should also be drilled at the corresponding positions at the connection ends.

5. The manufacturing method of a CFRP-aluminum alloy sandwich control arm with topology optimization design according to claim 1, characterized in that, The aluminum alloy sandwich layer of the sandwich control arm has three ends, with two ends used for bushing installation and the outer end used for ball joint connection.

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