An interlock structure for enhancing the bonding force of a metal and a composite material

Abstract

The utility model provides a kind of interlocking structure for enhancing the interlocking structure of metal and composite material bonding force, it is related to composite material product technical field, comprising: structure includes the metal piece of surface is equipped with reverse buckle structure, and the composite material body of the resin matrix being constituted by fiber reinforced material, composite material body wraps metal piece part outer surface and fills solidification in reverse buckle structure, forms mechanical interlocking.The utility model passes through mechanical interlocking structure, compared with pure cementing has higher bonding strength, better fatigue resistance and long-term reliability.Compared with screw connection, it is more beautiful, and lighter.The utility model structure performance improves significantly, and stability is better.

Description

Technical Field

[0001] This utility model mainly relates to the field of composite material products technology, specifically to an interlocking structure for enhancing the bonding force between metal and composite materials. Background Technology

[0002] Composite fiber materials (such as carbon fiber and glass fiber) are widely used due to their excellent specific strength and specific modulus. However, because these materials are usually formed through processes such as compression molding, winding, or resin transfer molding, it is difficult to directly form complex three-dimensional structures (such as bosses, threads, and snaps) on the composite material itself, which limits their application as functional structural components. Currently, adhesive bonding or continuous screw (bolt) fastening is commonly used, but the strength of adhesive bonding is difficult to control for consistent performance, and screw fastening cannot meet the industry's demand for lightweight designs. Therefore, a structural design is needed that can fundamentally improve the bonding strength between metal and composite materials, while simultaneously meeting the requirements of aesthetics and lightweight design, thus overcoming the shortcomings of composite panels in industrial applications. Utility Model Content

[0003] 1. The technical problem to be solved by the utility model: This invention provides an interlocking structure for enhancing the bonding force between metals and composite materials, thereby solving the technical problems existing in the background art.

[0004] 2. Technical Solution: To achieve the above objectives, the technical solution provided by this utility model is: an interlocking structure for enhancing the bonding force between metal and composite materials, comprising: A metal part, wherein at least a portion of the surface of the metal part is provided with an undercut structure; The composite material body, consisting of fiber-reinforced material and resin matrix, wraps around at least a portion of the outer surface of the metal part and fills and solidifies within the internal space of the inverted structure to form a mechanical interlock.

[0005] Preferably, the inverted structure includes one or more of the following: a truncated conical hole, a stepped hole, and a dovetail groove.

[0006] Preferably, the ratio of the depth to the opening width of the inverted structure is in the range of 0.5:1 to 3:1.

[0007] Preferably, the metal part is an insert, a connecting piece, or an integral skeleton structure.

[0008] Preferably, the fiber reinforcement material is carbon fiber or glass fiber fabric.

[0009] 3. Beneficial effects: Compared with the prior art, the technical solution provided by this utility model has the following advantages: This invention utilizes a mechanical interlocking structure formed between the metal component and the composite material, resulting in significantly higher bonding strength compared to traditional adhesive bonding. It also avoids reliability issues caused by fluctuations in adhesive properties and difficulty in controlling process consistency. Furthermore, its fatigue resistance and long-term stability are far superior to pure adhesive bonding structures. Compared to bolt connections, this invention eliminates the need for additional fasteners, avoiding the aesthetic imperfections associated with screws and achieving a cleaner appearance. It also eliminates the weight redundancy of fasteners, perfectly meeting the industry's design requirements for lightweight and thin composite components, resolving the contradiction between screw connections and lightweight aesthetics. Simultaneously, this interlocking structure boasts strong process repeatability and outstanding performance stability, making it suitable for mass production. It is also compatible with various fiber-reinforced materials such as carbon fiber and glass fiber, and the metal component can be flexibly designed as an insert, connecting piece, or integral skeleton, effectively compensating for the difficulty in forming complex three-dimensional structures in composite panels and further expanding its application scenarios. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a partial view of the undercut portion of this utility model; Figure 3 This is a schematic diagram of the metal part structure with stepped holes according to this utility model; Figure 4 This is a schematic diagram of the metal part structure in the form of a truncated conical hole according to this utility model; Figure 5 This is a schematic diagram of the metal part structure of the dovetail groove in the inverted state according to this utility model; Figure 6 This is a schematic diagram of the processing state of this utility model in the mold; Figure label: 1. Metal parts; 2. Composite material body; 11. Inverted structure. Detailed Implementation

[0011] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the utility model will be more thorough and complete.

[0012] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "page", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0013] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0014] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," and "equipped with" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0015] It should be noted that the structures not described in this utility model are the same as or can be implemented using existing technology, and will not be elaborated here, as they do not involve the design points and improvement directions of this utility model. Example

[0016] See attached document Figures 1-6 An interlocking structure for enhancing the bonding strength between metals and composite materials, comprising: Metal part 1, at least a portion of the surface of metal part 1 is provided with an undercut structure 11; The composite material body 2 is composed of fiber-reinforced material and resin matrix. The composite material body 2 wraps around at least part of the outer surface of the metal part 1 and fills and solidifies the internal space of the inverted structure 11 to form a mechanical interlock.

[0017] The inverted structure 11 includes one or more of the following: a truncated conical hole, a stepped hole, and a dovetail groove.

[0018] The ratio of the depth to the opening width of the inverted structure 11 ranges from 0.5:1 to 3:1.

[0019] Metal part 1 is an insert, connecting piece, or integral skeleton structure.

[0020] The fiber reinforcement material is carbon fiber or glass fiber fabric.

[0021] A method for an interlocking structure to enhance the bonding strength between metal and composite materials includes the following steps: S1. Provide a metal part 1 with an undercut structure 11; S2. Position the metal part 1 inside the cavity of the mold; S3. Introduce the fiber-reinforced material and resin matrix into the cavity in the form of thermoplastic sheets; S4. Apply pressure and heat to make the resin matrix flow and drive the fiber reinforcement material to penetrate and completely wrap the inverted structure 11 of the metal part 1. S5. Heat preservation and pressure preservation are used to cure the resin matrix and form a composite material body 2 that is mechanically interlocked with the metal part 1. S6. Open the mold and remove the formed composite component.

[0022] In step S3, the fiber reinforcement material and resin matrix are introduced in the form of prepreg or thermoplastic preform sheet.

[0023] In step S4, the resin matrix is ​​a thermoplastic resin.

[0024] In step S4, the pressure is 2-20 MPa, which needs to be obtained through testing based on the thickness of the plate and the complexity of the structure. The temperature is 100-150℃, referring to the technical parameters of the resin inside the carbon plate, to ensure that the resin is in a molten state.

[0025] Cavity temperature setting: The specifications are set according to the technical parameters of the thermoplastic resin used in the carbon fiber sheet;

[0026] Pressure setting: Setting the pressure primarily requires overcoming two major resistances: the viscous resistance of resin flow and the permeation resistance of the fiber network. This can be understood using a modified Darcy's law, as shown in the following formula:

[0027] Prequired (Required Pressure): The process pressure that needs to be calculated or determined.

[0028] μ (resin viscosity): This is the most critical factor. The viscosity of thermosetting resins changes drastically with temperature, typically reaching its lowest point within a specific temperature range.

[0029] L (flow length): The furthest distance the resin needs to flow to fill the undercut structure. The undercut depth (e.g., 0.2 mm) is also part of the flow length.

[0030] (Strain rate / flow rate): Related to mold closing speed. The faster the speed, the greater the pressure required.

[0031] K (permeability of fiber prepreg): closely related to fiber type, weaving method, and fiber volume content. The denser the fiber stacking, the lower the permeability and the higher the required pressure.

[0032] Establishing initial pressure based on experience: Based on Darcy's law, influencing factors are identified, and an initial pressure range is set. A common initial pressure setting range is used for experimentation. Validation and optimization through experiments (DOE)

[0033] Existing technologies achieve this through bolted connections or adhesive bonding. Bolted connections offer strong mechanical strength, but the screw-based fastening affects aesthetics and increases weight, contradicting current lightweight design trends. Adhesive bonding, while ensuring process consistency, is affected by the adhesive's properties. This technical solution utilizes the resin's flowability during molding to actively fill and form mechanical interlocks, fundamentally altering the bonding mechanism. This solution combines specific structural design with specific process conditions, generating a synergistic effect.

[0034] To verify the beneficial effects of this technical solution, a static tensile strength comparison test was conducted on the traditional adhesive joint and the mechanically interlocked joint of this technical solution, according to the test methods in GB / T 1447-2005 "Test Method for Tensile Properties of Fiber Reinforced Plastics". The test was carried out on a universal testing machine at a tensile speed of 2 mm / min, and the measured data are as follows:

[0035] Analysis of the measured data yields the following results:

[0036] The experimental data from this case study shows that: Significantly improved strength performance: The connection strength of the new mechanical interlocking structure reaches 53.1 N, which is 55.3% higher than that of the traditional adhesive solution (34.2 N), demonstrating a significant performance improvement.

[0037] Stability and consistency are significantly improved: the standard deviation of the interlocking structure is reduced to 1.6 N, which is 44.8% lower than the 2.9 N of the adhesive method; this indicates that the manufacturing process of the interlocking structure has better repeatability and consistency; the improved data concentration proves that the technology is more suitable for mass production.

[0038] Fundamental improvement in reliability: The weakest sample of the interlocking structure (50.5 N) is 47.7% higher than the average of the adhesive solution (34.2 N); the lower limit of the performance of the interlocking structure has exceeded the average level of the traditional solution.

[0039] Compared with existing technologies, this invention combines a specific undercut structure with an optimized molding process to form a mechanical interlocking system that offers higher bonding strength, better fatigue resistance, and longer-term reliability compared to pure adhesive bonding. It is more aesthetically pleasing and lighter than screw (bolt) connections, while offering higher bonding strength, significantly improved stability, and enhanced reliability compared to adhesive bonding.

[0040] The above-described embodiments are merely illustrative of certain implementations of this utility model, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An interlocking structure for enhancing the bonding force between metal and composite materials, characterized in that, include: Metal part (1), at least a portion of the surface of the metal part (1) is provided with an undercut structure (11). The composite material body (2) is composed of fiber-reinforced material and resin matrix. The composite material body (2) wraps around at least part of the outer surface of the metal part (1) and fills and solidifies the internal space of the inverted structure (11) to form a mechanical interlock.

2. The interlocking structure for enhancing the bonding force between metal and composite materials according to claim 1, characterized in that: The inverted structure (11) includes one or more of the following: truncated conical hole, stepped hole, and dovetail groove.

3. The interlocking structure for enhancing the bonding force between metal and composite materials according to claim 1, characterized in that: The ratio of the depth to the opening width of the inverted structure (11) ranges from 0.5:1 to 3:

1.

4. The interlocking structure for enhancing the bonding force between metal and composite materials according to claim 1, characterized in that: The metal part (1) is an insert, a connecting piece, or an integral skeleton structure.

5. The interlocking structure for enhancing the bonding force between metal and composite materials according to claim 1, characterized in that: The fiber reinforcement material is carbon fiber or glass fiber fabric.

Images