Composite material rapid melting interface microstructure and design method thereof

Abstract

The application belongs to the technical field of composite material rapid melting interface design and manufacturing, and particularly relates to a composite material rapid melting interface microstructure and a design method thereof, wherein the composite material rapid melting interface microstructure comprises a planar film microstructure, a plurality of through holes are formed in the planar film microstructure, the plurality of through holes are arranged in an array, the distance between adjacent two through holes is equal, a plurality of micro support structures are arranged along the circumference of the through holes, the micro support structures are arranged perpendicularly to the planar film microstructure, and the plurality of micro support structures are symmetrically arranged on the upper and lower sides of the planar film microstructure. The net-shaped planar microstructure designed independently promotes good contact between the microstructure and the composite material in the forming process, completely wets the surface of the composite material, forms a more uniform interface without a pore area, and thus improves the forming quality of the composite material structure.

Description

Technical Field

[0001] This invention belongs to the field of rapid melting interface design and manufacturing technology for composite materials, and particularly relates to a microstructure of rapid melting interface for composite materials and its design method. Background Technology

[0002] Advanced composite materials (CFRP) using carbon fiber as reinforcement have been widely used in aerospace, energy, automotive, and sports industries due to their advantages such as good dimensional stability, high specific strength, corrosion resistance, and fatigue fracture resistance. In recent years, the development of integrated composite molding technology has been particularly rapid. However, in some major engineering fields such as aerospace, the demand for composite material joining technologies continues, and new joining technologies are constantly being optimized to improve overall structural strength, cost savings, and lightweighting. Therefore, the necessity of developing composite material manufacturing technology is fully demonstrated. Currently, composite material joining manufacturing technologies are mainly divided into three types: mechanical joining, adhesive bonding, and melt bonding. Among them, mechanical joining is the earliest and most mature joining method, and it has been widely used in aerospace. However, due to the special network structure of CFRP, the internal carbon fibers are cut and damaged when making bolt holes, reducing fiber continuity. Due to the interruption of force transmission, a new critical destructive force value is generated under loading, thereby reducing the system's load-bearing capacity. Adhesive bonding technology has also developed rapidly. Like mechanical joining, it is suitable for thermoplastic and thermosetting matrices. Adhesive bonding can effectively reduce structural weight, while reducing manufacturing costs and improving damage tolerance. However, the process may introduce exogenous materials, which may contaminate the interface and add extra weight to the joint.

[0003] Melt bonding refers to heating the resin at the interface to a viscous state, causing the resin matrix to diffuse into each other, and then cooling to form a bond. It boasts numerous advantages, including no need for flux or external heating during the molding process, minimal damage to the composite material, short molding time (generally less than 1 second), high structural strength, low residual strain, and ease of automation, making it considered one of the most promising bonding technologies for advanced composite materials. During the melt bonding process, a resin-based microstructure needs to be placed at the bonding interface. This microstructure is typically used to increase energy transfer, shorten molding time, and reduce edge stress concentration. This microstructure can be a resin protrusion or an artificially created protrusion on the composite material surface. Due to the presence of the microstructure, frictional heat can preferentially be generated on the resin surface at the bonding interface, and viscoelastic heat can be generated between the molecular chains due to friction. Therefore, the resin-based microstructure has a significant impact on the interfacial bonding and mechanical properties of the bonded composite.

[0004] Current research indicates that different microstructure shapes significantly affect the welding interface temperature. Triangular and semi-circular structures can achieve higher interface temperatures, but due to structural asymmetry, they can also cause localized overheating or incomplete welds. Planar structures, on the other hand, may retain a thin film in parts of the weld due to incomplete melting, significantly reducing weld strength and leading to uneven welds. To improve the structural strength of composite materials, more adaptable structural designs are needed, while simultaneously meeting stringent requirements such as simplicity, effectiveness, ease of implementation, and process feasibility. Summary of the Invention

[0005] The purpose of this invention is to provide a microstructure of a rapid melting interface in composite materials and its design method, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides a composite material rapid melting interface microstructure, including a planar thin film microstructure. The planar thin film microstructure has a plurality of through holes arranged in an array, and the distance between two adjacent through holes is equal. A plurality of micro support structures are arranged along the circumference of the through holes. The micro support structures are arranged perpendicular to the planar thin film microstructure, and the plurality of micro support structures are symmetrically arranged on the upper and lower sides of the planar thin film microstructure.

[0007] Preferably, the through hole is either a circular hole or a regular polygonal hole.

[0008] Preferably, the plurality of through holes are arranged in a rectangular array, and four adjacent through holes are equally spaced along the circumference of the micro-support structure.

[0009] Preferably, when the through hole is a regular polygonal hole, a plurality of the micro-support structures are respectively disposed at the vertices of the regular polygonal hole.

[0010] Preferably, when the through hole is a circular hole, a plurality of the micro-support structures are arranged at equal intervals along the circumference of the through hole.

[0011] Preferably, the microsupport structure is one of a hemispherical microstructure, a regular pyramidal microstructure, or a regular frustum-shaped microstructure.

[0012] This invention provides a method for designing microstructures at rapid melting interfaces of composite materials, comprising the following steps:

[0013] Step 1: Determine the outline dimensions of the planar thin film microstructure based on the area of ​​the composite material molding interface and cut it accordingly;

[0014] Step 2: Determine the shape of the through-hole and create the hole in the planar thin film microstructure;

[0015] Step 3: Based on the shape of the through hole, fix the micro-support structure onto the surface of the planar thin film microstructure.

[0016] Preferably, before making openings in the planar thin-film microstructure, the opening positions are determined and marked on the planar thin-film microstructure; before fixing the micro-support structure to the planar thin-film microstructure, the fixing positions of the micro-support structure are determined and marked on the planar thin-film microstructure.

[0017] Preferably, when the micro-support structure is fixed to the planar thin-film microstructure, the large-face end of the micro-support structure is fixed to the planar thin-film microstructure.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] 1. The present invention provides a composite material rapid melting interface microstructure that leverages the advantages of various simple solid configuration microstructures, maintaining high strength while also possessing advantages such as rapid melting and short welding time.

[0020] 2. The mesh-like planar microstructure independently designed in this invention promotes good contact between the microstructure and the composite material during the molding process, completely wets the surface of the composite material, forms a more uniform interface, and has no porous areas, thereby improving the molding quality of the composite material structure.

[0021] 3. The interfacial microstructure proposed in this invention enables advanced large-scale molding processes for composite materials. Under pressure applied by the welding head, the more flexible microstructure undergoes greater deformation, which promotes better contact with the composite material and thus improves interfacial melting. Furthermore, the uniform deformation of the interfacial microstructure can bond the entire interface, thereby reducing interfacial voids. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a microstructure of a rapid melting interface of composite materials proposed in this invention;

[0024] Figure 2 This is a schematic diagram of the regular pyramidal microstructure in this invention;

[0025] Figure 3 This is a schematic diagram of the hemispherical microstructure in this invention;

[0026] Figure 4This is a schematic diagram of the frustum-shaped microstructure in this invention;

[0027] Figure 5 This is a schematic diagram of the microstructure of the rapid melting interface of the composite material in Embodiment 3 of the present invention;

[0028] Among them: 1. Planar thin film microstructure; 2. Micro support structure; 3. Through hole; 101. Hole; 201. Connecting post; 202. Mounting hole. Detailed Implementation

[0029] The technical solutions of 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.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Example 1:

[0032] Reference Figures 1 to 4 As shown, the present invention provides a composite material rapid melting interface microstructure, including a planar thin film microstructure 1, on which a plurality of through holes 3 are formed, the plurality of through holes 3 are arranged in an array, and the distance between two adjacent through holes 3 is equal. A plurality of micro support structures 2 are arranged along the circumference of the through holes 3, the micro support structures 2 are arranged perpendicularly to the planar thin film microstructure 1, and the plurality of micro support structures 2 are symmetrically arranged on the upper and lower sides of the planar thin film microstructure 1.

[0033] A mesh-like planar microstructure is formed by opening several through holes 3 in the planar thin film microstructure 1. In this embodiment, the thickness of the planar thin film microstructure is 0.4 mm, the through holes 3 are square holes with a cutting length of 17.8 mm, the micro support structure 2 is a regular square pyramid microstructure, which is composed of four triangular inclined planes with an inclination angle of 45°. The large face of the regular square pyramid microstructure is a square with a side length of 4 mm and a height of 2 mm.

[0034] Furthermore, the through hole 3 is either a circular hole or a regular polygonal hole.

[0035] Furthermore, several through holes 3 are arranged in a rectangular array, with four adjacent through holes 3 being equally spaced along the circumference of the micro-support structure 2.

[0036] Furthermore, when the through hole 3 is a regular polygonal hole, several micro-support structures 2 are respectively set at the vertices of the regular polygonal hole.

[0037] Furthermore, when the through hole 3 is a circular hole, several micro-support structures 2 are arranged at equal intervals along the circumference of the through hole 3.

[0038] Furthermore, the micro-support structure 2 is one of a hemispherical microstructure, a regular pyramidal microstructure, or a regular frustum-shaped microstructure.

[0039] Example 2:

[0040] Reference Figures 1 to 4 As shown, this invention provides a method for designing microstructures at the rapid melting interface of composite materials, comprising the following steps:

[0041] Step 1: Determine the outline dimensions of the planar thin film microstructure 1 based on the area of ​​the composite material molding interface and cut it accordingly;

[0042] Step 2: Determine the shape of the through hole 3 and make an opening in the planar thin film microstructure 1;

[0043] Step 3: Based on the shape of the through hole 3, fix the micro support structure 2 onto the surface of the planar thin film microstructure 1.

[0044] Furthermore, before making openings on the planar thin film microstructure 1, the opening positions are determined and marked on the planar thin film microstructure 1; before fixing the micro support structure 2 on the planar thin film microstructure 1, the fixing positions of the micro support structure 2 are determined and marked on the planar thin film microstructure 1.

[0045] Furthermore, when the micro-support structure 2 is fixed to the planar thin film microstructure 1, the large surface end of the micro-support structure 2 is fixed to the planar thin film microstructure 1.

[0046] In this embodiment, heating can be used to fix the micro-support structure 2 to the planar thin film microstructure 1.

[0047] In this invention, the interface microstructure is sandwiched between the interfaces of two objects to be connected. It is important to note that the edge contour of the interface microstructure matches the interface between the two objects and is then clamped using auxiliary fixtures. The main body of the interface microstructure in this invention is a mesh structure, which is more flexible and can better conform to the interface of the objects to be connected, especially solving the connection of interfaces with concave and convex curved surface features. After clamping and fixing with auxiliary fixtures, ultrasonic welding is used for welding. Because the micro-support structure 2 has little material at the connection interface, it melts easily. The melted liquid quickly fills the through-hole 3 under the capillary action of the through-hole 3. It should be noted that because the micro-support structure 2 is a symmetrical structure, it is heated evenly during welding, thus achieving full melting and filling of the through-hole 3. The volume and number of micro-support structures 2 are calculated based on the area of ​​the through-hole 3. Then, the entire interface microstructure melts and completely wets the surface of the composite material. Finally, it is allowed to fully solidify before the object is removed from the auxiliary fixture for inspection.

[0048] Example 3:

[0049] Reference Figure 5 As shown, the difference between this embodiment and embodiments one and two is that a connecting post 201 is fixedly connected to the middle of the large end of one micro-support structure 2 to form a type A micro-support structure; another micro-support structure 2 has a mounting hole 202 adapted to the connecting post 201 in the middle of the large end to form a type B micro-support structure. The type A and type B micro-support structures can be integrally molded by injection molding and used as standard parts of different sizes, improving versatility and reducing processing costs. A hole 101 is opened at the position where the planar thin film microstructure 1 needs to be fixed. The diameter of the hole 101 is equal to the diameter of the connecting post 201. The end of the connecting post 201 away from the micro-support structure 2 passes through the hole 101 and transitions with the mounting hole 202 to realize the fixed connection of the type A and type B micro-support structures. The planar thin film microstructure 1 is sandwiched between the type A and type B support structures, eliminating the process of heating and fixing, improving the consistency and reliability of the connection between the type A and type B micro-support structures on the planar thin film microstructure 1, saving time and reducing costs.

[0050] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, 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 invention.

[0051] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A microstructure of a rapid melting interface for composite materials, characterized in that, The microstructure includes a planar thin film microstructure (1), which has a plurality of through holes (3) arranged in an array, with the distance between two adjacent through holes (3) being equal. A plurality of micro support structures (2) are arranged along the circumference of the through holes (3), and the micro support structures (2) are arranged perpendicular to the planar thin film microstructure (1). The plurality of micro support structures (2) are symmetrically arranged on the upper and lower sides of the planar thin film microstructure (1). One of the micro-support structures (2) has a connecting column (201) fixedly connected to the middle of its large end to form a type A micro-support structure; the other micro-support structure (2) has an installation hole (202) adapted to the connecting column (201) in the middle of its large end to form a type B micro-support structure. A hole (101) is opened on the planar thin film microstructure (1), one end of the connecting column (201) passes through the hole (101) and transitionally fits with the installation hole (202). The planar thin film microstructure (1) is sandwiched between the type A micro-support structure and the type B micro-support structure.

2. The composite material rapid melting interface microstructure according to claim 1, characterized in that, The through hole (3) is either a circular hole or a regular polygonal hole.

3. The composite material rapid melting interface microstructure according to claim 1, characterized in that, Several through holes (3) are arranged in a rectangular array, and four adjacent through holes (3) are equally spaced along the circumference of the micro support structure (2).

4. The composite material rapid melting interface microstructure according to claim 2, characterized in that, When the through hole (3) is a regular polygonal hole, several micro-support structures (2) are respectively located at the vertices of the regular polygonal hole.

5. The composite material rapid melting interface microstructure according to claim 2, characterized in that, When the through hole (3) is a circular hole, several micro support structures (2) are arranged at equal intervals along the circumference of the through hole (3).

6. The composite material rapid melting interface microstructure according to claim 1, characterized in that, The micro-support structure (2) is one of a hemispherical microstructure, a regular pyramidal microstructure, or a regular frustum-shaped microstructure.

7. A method for designing the microstructure of the rapid melting interface of composite materials according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Determine the outline dimensions of the planar thin film microstructure (1) based on the area of ​​the composite material molding interface and cut it accordingly; Step 2: Determine the hole shape of the through hole (3) and make openings in the planar thin film microstructure (1); Step 3: Based on the hole shape of the through hole (3), fix the micro support structure (2) onto the surface of the planar thin film microstructure (1).

8. The design method for the microstructure of the rapid melting interface of composite materials according to claim 7, characterized in that, Before making openings on the planar thin film microstructure (1), the opening positions are determined and marked on the planar thin film microstructure (1); before fixing the micro support structure (2) on the planar thin film microstructure (1), the fixing positions of the micro support structure (2) are determined and marked on the planar thin film microstructure (1).

9. The design method for the microstructure of the rapid melting interface of composite materials according to claim 7, characterized in that, When the micro-support structure (2) is fixed to the planar thin film microstructure (1), the large end of the micro-support structure (2) is fixed to the planar thin film microstructure (1).

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