CN113719504A

CN113719504A - Composite material interface connecting structure and method

Info

Publication number: CN113719504A
Application number: CN202110887788.2A
Authority: CN
Inventors: 刘铁让; 高丽敏; 陈程; 奚晓波; 李星; 宋彦辉; 李晨
Original assignee: Commercial Aircraft Corp of China Ltd; Beijing Aeronautic Science and Technology Research Institute of COMAC
Current assignee: Commercial Aircraft Corp of China Ltd; Beijing Aeronautic Science and Technology Research Institute of COMAC
Priority date: 2021-08-03
Filing date: 2021-08-03
Publication date: 2021-11-30

Abstract

The invention provides a composite material interface connection structure and a method, which relate to the technical field of structural design of airplane bodies, and are connected by adopting two force transmission modes of point force transmission and surface force transmission, so that the requirement on the strength of a bolt in the traditional point force transmission connection can be greatly reduced, the rigidity of the structure can be improved, and the slippage problem can be effectively improved; the method comprises the steps that shear keys are arranged on meshing layers of components to be connected, the components to be connected are connected through the shear keys, and meanwhile, the components to be connected are fixedly connected through bolts or nails, so that a force transmission path is in a mode of combining a surface force transmission path and a point force transmission path; a bottom film is arranged between the shear key and the member to be connected so as to enhance the cementing property of the shear key or provide an electrochemical corrosion insulating layer; the shearing keys on the two members to be connected are alternately arranged; the base film on one of the members to be connected is connected with the shear bond on the other member to be connected. The technical scheme provided by the invention is suitable for the connection design of the composite material structure.

Description

Composite material interface connecting structure and method

Technical Field

The invention relates to the technical field of airplane body structure design, in particular to a composite material interface connecting structure and a method.

Background

At present, in the structural design of a composite material airplane, the traditional bolt connection design concept is applied, and the safety margin of the structure is controlled by the extrusion stress of bolt holes or nail hole edges at the connection positions between components or between components in many cases. Therefore, in order to improve the design margin, it is generally necessary to increase the thickness of the composite structure at the joint, or the diameter of the bolt or nail, or the number of fasteners, or the like. It is obvious that such a method would add to some extent the weight of the structure. Moreover, by applying the traditional bolt connection design concept, high-performance bolts are required to meet the strength requirement in some key connection areas such as wing roots, and the high-performance bolts are undoubtedly not beneficial to improving the economy of the structural design. Also, in the conventional bolt connection design, due to the gap between the bolt and the hole wall and the deformation possibly caused by the compression between the bolt and the hole wall under load, a small slip may occur between the connecting pieces, which directly affects the overall rigidity of the structure, such as the overall rigidity of the wing.

There are also a number of solutions for interfacing in the prior art. Such as: patent 200810064671.9 discloses a method of joining a metallic material and a non-metallic composite material. The method adopted by the document is to increase the bonding strength of the metal and nonmetal interfaces by adding a metal powder layer between the metal and nonmetal material connecting interfaces and then welding the metal powder layer and the nonmetal material connecting interfaces together by AgCu at high temperature. But it requires a high temperature welding operation and is not detachable. Patent 202021424249.2 discloses a connection of a round metal piece to a fiber reinforced composite material. The method comprises the steps of firstly arranging a plurality of grooves on the connecting surface of a metal plate, then filling the grooves with umbrella-shaped fiber bundles inserted into a composite piece, and finally pouring resin for curing and molding. On one hand, the grooves have influence on the strength of the connecting piece, and on the other hand, the umbrella-shaped fiber bundles are connected with the grooves and the fiber cloth and the pouring molding operation is complex. Patent 201710195926.4 discloses a butt joint structure of wing wall panels, which is formed by directly butt-jointing two wing wall panels, and connecting band plates are respectively arranged at the upper and lower sides of the butt joint part and are engaged with the surfaces of the wing wall panels. The connecting mode needs to process the connecting piece, namely the wing wall plate, so that the connecting piece can be meshed with the connecting strip plate, the shape change of the connecting piece is large, and the use scene is limited.

Accordingly, there is a need to develop a composite interfacing structure and method that addresses the deficiencies of the prior art to solve or mitigate one or more of the problems set forth above.

Disclosure of Invention

In view of the above, the invention provides a composite material interface connection structure and a method, which adopt two force transmission modes of point force transmission and surface force transmission for connection, can greatly reduce the requirement on the strength of a bolt in the traditional point force transmission connection, can improve the strength and rigidity of the structure, and effectively improve the slippage problem.

In one aspect, the present disclosure provides a composite interfacing structure comprising a first member and a second member to be joined; the surface of the first member is provided with a first meshing layer, and the surface of the second member is provided with a second meshing layer; the first engagement layer comprises a first shear key and the second engagement layer comprises a second shear key; the first meshing layer and the second meshing layer are meshed and connected through the first shearing key and the second shearing key;

the first member and the second member are fastened and connected by bolts or nails.

The above aspects and any possible implementations further provide an implementation in which the first bonding layer further comprises a first base film, and the first member, the first base film, and the first shear key are sequentially adhesively connected;

the second meshing layer further comprises a second base film, and the second member, the second base film and the second shear keys are sequentially connected in a gluing mode.

The above aspect and any possible implementation further provide an implementation in which the first and second shear keys are each shaped in any one or more of a strip, an arc, and a circle.

The above aspect and any possible implementation further provide an implementation where the first shear key and the second shear key are disposed at a distance apart at the bolt. That is, the bolt may not be provided with the first shear key or the second shear key.

The above aspect and any possible implementation manner further provide an implementation manner, where the first bottom film and the second bottom film are graphene films, carbon fiber composite films, or metal material films.

The above aspect and any possible implementation manner further provide an implementation manner, wherein the first shear key and the second shear key are made of graphene, a carbon fiber composite material, or a metal material.

In another aspect, a method of interfacing a composite material, adapted for use in an interfacing structure as described in any one of the preceding claims;

according to the method, the shearing key for meshing is arranged on the joint surface of the component to be connected, the shearing force is transmitted through the shearing key, and meanwhile, the fastening force is provided for the component to be connected through the bolt or the nail, so that the force transmission path is a mode of combining surface force transmission and point force transmission.

The above aspect and any possible implementation manner further provide an implementation manner, wherein a bottom film is further disposed between the shear key and the member to be connected, and the bottom film is used to enhance the connection strength between the shear key and the member to be connected or provide an electrochemical corrosion insulating layer.

The above aspect and any possible implementation manner further provide an implementation manner, and when the members to be connected, the base film and the shear keys are sequentially glued and connected.

The above aspect and any possible implementation further provide an implementation where the shear keys are disposed at a distance apart at the bolt, i.e., where the shear keys are not disposed.

The bolt can also be provided with a shear key, but the shear key is easy to cause the mutual interference of point force transmission and surface force transmission.

Compared with the prior art, one of the technical schemes has the following advantages or beneficial effects: the invention provides a new force transmission path besides bolts or nails, namely, the connecting interfaces are connected with the bottom film through shear keys; in essence, as the traditional point force transmission path based on the bolt is developed into a point-surface combined multi-force transmission path design, namely, the load transmission mode is converted from point load transmission at the bolt to interface shear keys distributed in an array, more flexibility is provided for the structural connection design, and the shear load which the bolt or the nail in the traditional design should bear is partially or completely converted into the transmission from the shear keys between the connection interfaces;

another technical scheme in the above technical scheme has the following advantages or beneficial effects: due to the double shear load transfer mode, the requirements on high-strength bolts can be greatly reduced, the problem that the traditional connection is likely to slide can be eliminated, and the rigidity of the structure can be improved;

another technical scheme in the above technical scheme has the following advantages or beneficial effects: reinforcing the cementing property of a shear bond by arranging a bottom film or providing a possible electrochemical corrosion insulating layer according to requirements;

another technical scheme in the above technical scheme has the following advantages or beneficial effects: the structure is safer and more reliable, and once the interface layer is meshed and loses efficacy, the bolt can transmit shearing load in a traditional bolt mode;

another technical scheme in the above technical scheme has the following advantages or beneficial effects: the invention can be applied to the connection design between the structural binding surfaces in a wide sense, such as the connection between the wing beam and the skin, the connection between the skin and the stringer and the like.

Of course, it is not necessary for any one product in which the invention is practiced to achieve all of the above-described technical effects simultaneously.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a diagram of a composite interface connection architecture provided by one embodiment of the present invention;

fig. 2 is a schematic structural view of a first member and a second member provided in one embodiment of the present invention.

Wherein, in the figure:

1. a first member; 2. a second member; 3. a first engaging layer; 4. a second engaging layer; 5. fastening a bolt; 31. a first base film; 32. a first shear key; 41. a second base film; 42. a second shear key.

Detailed Description

For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In response to the deficiencies of the prior art, the present invention provides a design concept for a connection by interfacially engaging, i.e., converting, partially or even fully, the shear loads that a bolt or nail would be subjected to in conventional mechanical connection designs into being transmitted by interengagement between the connection interfaces. On the basis, a mode of adding an interface shear key is further provided to partially or completely convert shear load which a bolt or a nail in the traditional mechanical connection design should bear into transmission of the shear key between the connection interfaces. The shear key is designed using high strength, high modulus and wear resistant high performance materials such as graphene films and the like. The technology can be applied to various strip plate connection scenes, and can also be popularized and applied to assembly connection on a common airplane, such as the situation only comprising one binding surface, including connection of a wing spar and a skin, connection of a wing rib and a fuselage frame and the skin, even connection of a stringer and the skin, and the like.

As shown in fig. 1 and 2. The first member 1 and the second member 2 are two members to be interfaced. Be provided with first meshing layer 3 on the face of being connected of first component 1, be provided with second meshing layer 4 on the face of being connected of second component 2, two meshing layers laminate and connect to carry out fore-and-aft fastening connection to two components with a plurality of fastening bolt 5. The first bonding layer 3 includes a first base film 31 having a thin layer shape and first shear keys 32 provided on a surface of the first base film 31. The second bonding layer 4 includes a second carrier film 41 having a thin layer shape and second shear keys 42 disposed on a surface of the second carrier film 41. Whether a base film is required or not can be determined according to circumstances. The first carrier film and the second carrier film are respectively connected with the attaching surfaces of the first member and the second member through gluing; the first cutting key and the second cutting key are respectively connected with the first bottom die and the second bottom die through gluing, or directly glued with the joint surface of the first member and the second member to be connected when the bottom die is not used.

First, a high-strength, high-modulus and abrasion-resistant base film of a high-performance material, such as a graphene film, various composite films, etc., is bonded to the faying surfaces of two members (the first member 1 and the second member 2) to be joined, so as to better bond shear bonds while avoiding possible electrochemical corrosion problems. Then, a sheet-like shear bond made of an array of high modulus and abrasion resistant high performance materials such as graphene, carbon fiber composite, and even metal materials is bonded to the base film, thereby forming the engaging layers (the first engaging layer 3 and the second engaging layer 4) on the mating surface of the member. The shear keys may be configured in a variety of shapes, such as a ribbon, an arc, a circle, and the like. The planar dimensions, thicknesses and number of shear keys can be designed with simplified engineering methods depending on the material properties and shear loads to be borne. Finally, the members with the engaging layers are stacked together and fastened by the fastening bolts 5.

The steps of the connection mode include:

step 1: preparing a component and a material for manufacturing a meshing layer; the preparation of the joint face of the component is in accordance with the requirements of the general cementing technique, and the purpose is to provide a surface for cementing a bottom die or directly bonding a shear key. The material of the bottom die is selected to avoid the problem of electrochemical corrosion between the connecting interfaces.

Step 2: bonding an engaging layer on the member jointing surface; the bonding of the bottom die and the bonding of the shear key can be performed by conventional methods, such as epoxy resin.

And step 3: and (5) overlapping and fastening by bolts.

This design approach provides a new layer of engagement between the force path-connection interface in addition to the bolts or nails, as compared to conventional connection designs. In essence, it provides more flexibility for structural connection design as it evolves the traditional bolt-based point force transfer approach to a point-to-surface bonded multiple force transfer path design. By utilizing the design concept, the requirements on high-strength bolts can be greatly reduced, and space is provided for further optimizing the thicknesses of components such as skins and wall plates. By using the method, the structural design margin which is dominated by bolt or nail hole extrusion in the traditional design is no longer a problem, and the required structural design margin is not required to be realized by increasing the thickness of a component, so that a new way is opened for further weight reduction. Moreover, the design concept can also eliminate the possible slippage between the traditional connecting design parts, such as the wing root joint, the butt joint area of the wing beam and the like, thereby improving the rigidity of the structure. Finally, this design approach will make the structure more secure and reliable because the bolts can also transmit shear loads in a conventional manner once the interface layer engagement fails.

The composite material interface connection structure and method provided by the embodiments of the present application are described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims

1. A composite interfacing structure, comprising a first member and a second member to be joined; the surface of the first member is provided with a first meshing layer, and the surface of the second member is provided with a second meshing layer; the first engagement layer comprises a first shear key and the second engagement layer comprises a second shear key; the first meshing layer and the second meshing layer are meshed and connected through the first shearing key and the second shearing key;

2. The composite interfacing structure of claim 1, wherein said first bonding layer further comprises a first carrier film, said first member, said first carrier film and said first shear bond being sequentially adhesively bonded;

3. The composite interfacing structure of claim 1, wherein the first shear key and the second shear key are each shaped in any one or more of a strip, an arc, and a circle.

4. The composite interfacing structure of claim 1, wherein the first shear key and the second shear key are disposed a distance apart at the bolt.

5. The composite interfacing structure of claim 1, wherein the first base film and the second base film are graphene films or composite films.

6. The composite interfacing structure of claim 1, wherein the first shear key and the second shear key are made of graphene, carbon fiber composite, or metal.

7. The composite material interface connection method is characterized in that shear keys for meshing are arranged on the joint surfaces of members to be connected, shear force transmission is carried out through the shear keys, meanwhile, fastening force is provided for the members to be connected through bolts or nails, and a force transmission path is in a mode of combining surface force transmission and point force transmission.

8. The composite interfacing method of claim 7, wherein a carrier film is further disposed between the shear key and the member to be connected, and the carrier film is used to enhance the connection strength between the shear key and the member to be connected or provide an electrochemical corrosion insulation layer.

9. The composite interfacing method of claim 8, wherein the members to be joined, the base film, and the shear keys are sequentially bonded together by gluing.

10. The composite interfacing method of claim 7, wherein the shear keys are spaced apart at the bolt.