Mixed connection structure of metal-free composite material foam sandwich panel

Abstract

The invention discloses a mixed connection structure of a metal-free composite material foam sandwich panel, which is characterized in that two opposite side surfaces of a composite material connecting piece are respectively provided with a groove, and the two grooves are symmetrically arranged; the multiple groups of first composite material foam sandwich panels and the multiple groups of second composite material foam sandwich panels are symmetrically arranged relative to the center line of the composite material connecting piece, and the center line is parallel to the first direction; the two composite material reinforced cover plates respectively cover two outer side surfaces of the plurality of groups of first composite material foam sandwich plates and the plurality of groups of second composite material foam sandwich plates; the connecting holes penetrate through the composite material reinforcing cover plates, the composite material plates and the composite material connecting pieces, the composite material reinforcing cover plates, the composite material plates and the composite material connecting pieces are fixed through the fiber bundles between the connecting holes, and the whole connecting structure is free of bolts and metal elements, is a pure composite material connecting structure, and is simple in structure and easy to achieve.

Description

Technical Field

[0001] The present application relates to the technical field of composite material connectors, and in particular to a hybrid connection structure of metal-free composite material foam sandwich panels. Background Art

[0002] Composite materials have the characteristics of high strength, high stiffness, low thermal expansion coefficient, non-magnetic and material designability. Compared with traditional metal structures, composite materials can improve structural efficiency and functionality, but due to limitations in design, manufacturing and maintenance, there must be certain connection structures and separation surfaces. These connection parts are generally the weak links of the structure. Studies have shown that 70% of the failure of composite materials occurs at the connection, and 30% of the weight is caused by the connection. Compared with metal structures, non-metal composite material connections are more complicated. The performance of non-metal composite materials is closely related to their geometry, ply design, connection method and load conditions, and the failure and damage modes are more diverse. These characteristics also make composite material connections more designable and more research-oriented. Summary of the invention

[0003] The main purpose of the present application is to provide a hybrid connection structure of a metal-free composite foam sandwich panel, aiming to realize a non-metal composite connection structure without metal and bolts and with higher mechanical performance requirements.

[0004] To achieve the above-mentioned purpose, the present application provides a hybrid connection structure of metal-free composite foam sandwich panels, including: a composite connector, each of the two opposite sides is provided with a groove, and the two grooves are symmetrically arranged; multiple groups of first composite foam sandwich panels, each group of composite foam sandwich panels includes two layers of composite panels arranged opposite to each other, each of the composite panels has a platform close to the edge of the other composite panel, the inner edges of the two platforms are respectively abutted against the edges of the two grooves along the second direction, and a composite foam core is sandwiched between the two composite panels, one side of the composite foam core is clamped to the first end of the composite connector along the second direction, and the second direction is vertical Perpendicular to the first direction, multiple groups of the first composite foam sandwich panels are arranged in parallel along the groove; multiple groups of second composite foam sandwich panels are symmetrically arranged with multiple groups of the first composite foam sandwich panels about the center line of the composite connector, and the center line is parallel to the first direction; two composite reinforced cover panels are respectively covered on two outer side surfaces of the multiple groups of the first composite foam sandwich panels and the multiple groups of the second composite foam sandwich panels; connecting holes pass through the composite reinforced cover panels, the composite panels and the composite connector, and each of the composite reinforced cover panels, the composite panels and the composite connector is fixed by the fiber bundles between the connecting holes.

[0005] Optionally, the platform is a right-angled trapezoidal platform, the cross-section of the composite connector along the second direction is spindle-shaped, the width of the groove of the composite connector at the bottom along the second direction is a, the width of the platform along the second direction is b, and the value of a is greater than or equal to twice b.

[0006] Optionally, a side of the composite foam core close to the composite connector has a V-shaped groove, and the V-shaped groove is matched and connected with two outer side surfaces of the spindle shape.

[0007] Optionally, there are two groups of connecting holes, which are respectively located on both sides of the groove, each group of connecting holes is arranged along the extension direction of the groove, and the two groups of connecting holes respectively penetrate the platforms of multiple groups of the first composite foam sandwich panels and the platforms of multiple groups of the second composite foam sandwich panels.

[0008] Optionally, the composite material connector is formed by short fiber reinforcement compression molding.

[0009] Optionally, after each of the composite material reinforced cover plates, the composite material plates and the composite material connecting pieces are fixed by fiber bundles between the connecting holes, vacuum-assisted resin injection is used in each of the connecting holes for reinforcement and molding.

[0010] Optionally, each of the composite material reinforced cover plates and the composite material plates are formed by pultrusion of long fiber glass and epoxy resin.

[0011] Optionally, the composite material connector is formed by compression molding of short fiber glass and epoxy resin.

[0012] The embodiment of the present application proposes a hybrid connection structure of a metal-free composite foam sandwich panel, in which a groove is provided on each of the opposite sides of two pieces connected by the composite material, and the two grooves are symmetrically arranged; a plurality of groups of first composite foam sandwich panels, each group of composite foam sandwich panels includes two layers of composite panels arranged oppositely, each composite panel has a platform close to the edge of the other composite panel, the inner edges of the two platforms are respectively against the edges of the two grooves along the second direction, and a composite foam sandwich is sandwiched between the two composite panels, one side of the composite foam sandwich is clamped to the first end of the composite connector along the second direction, the second direction is perpendicular to the first direction, and the plurality of first composite foam sandwich panels are arranged in parallel along the groove; a plurality of groups The second composite foam sandwich panel is symmetrically arranged with the multiple groups of first composite foam sandwich panels about the center line of the composite connecting piece, and the center line is parallel to the first direction; two composite reinforced cover panels are respectively covered on the two outer side surfaces of the multiple groups of first composite foam sandwich panels and the multiple groups of second composite foam sandwich panels; connecting holes penetrate the composite reinforced cover panels, the composite panels and the composite connecting pieces, and each composite reinforced cover panel, the composite panel and the composite connecting piece are fixed by the fiber bundles between the connecting holes. The overall connection structure of the present application has no bolts and metal elements and is a pure composite connection structure. Compared with traditional metal connections and existing hybrid connection methods, the structure of the present invention is simple, easy to implement, and has diversified application environments and conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the assembly state of an embodiment of a hybrid connection structure of a metal-free composite foam sandwich panel provided in the present application;

[0014] Figure 2 A schematic diagram of the disassembled state structure of an embodiment of a hybrid connection structure of a metal-free composite material foam sandwich panel of the present application is provided.

[0015] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0016] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0017] In the fields of modern weapons, aerospace, etc., composite materials are generally used in consideration of wave transmission and lightweight requirements. In order to avoid complex electromagnetic interference, metal and bolt connection structures are generally not allowed in their structural connections. The present invention relates to a metal-free composite material connection joint, which is used for the connection of composite foam sandwich panels.

[0018] At present, composite sandwich structures have various forms, processing methods and material selection, which greatly enhances the designability of composite sandwich structures. In recent years, more and more research has been conducted on composite sandwich structures. However, none of the patents involve research on metal-free composite foam sandwich structures with special requirements such as wave transmission and electromagnetic interference. There is no report on composite sandwich structures with composite connectors and foam sandwich connection structures using fiber bundle (3) threading technology.

[0019] Reference Figure 1 The first embodiment of the present application provides a hybrid connection structure of metal-free composite foam sandwich panels. The hybrid connection structure of metal-free composite foam sandwich panels may include a composite connector 6, multiple groups of first composite foam sandwich panels, multiple groups of second composite foam sandwich panels and a connection hole 2, wherein the two opposite sides of the composite connector 6 are symmetrically arranged about the center of the composite connector 6, and the two opposite sides are provided with a groove 601, and the two grooves 601 are symmetrically arranged about the center of the composite connector 6; each group of the multiple groups of first composite foam sandwich panels includes two oppositely arranged composite panels 4 and a composite foam sandwich 5 sandwiched between the two composite panels 4, and each composite panel 4 has a composite foam sandwich 5 sandwiched between the two composite panels 4, and the inner edge of each composite panel 4 close to the other ... metal-free composite foam sandwich panels provided in the first embodiment of the present application. There is a platform 401, and the two platforms 401 are respectively clamped in the two grooves 601, the composite foam sandwich 5 is matched and connected with the outer side of the composite connecting piece 6, and multiple groups of first composite foam sandwich panels are arranged along the first direction; multiple groups of second composite foam sandwich panels and multiple groups of first composite foam sandwich panels are axially symmetrically arranged about the composite connecting piece 6; two composite reinforced cover plates 1, each composite reinforced cover plate 1 is covered on the outer side of the same side of the multiple groups of first composite foam sandwich panels and the multiple groups of second composite foam sandwich panels; the connecting hole 2 runs through the two composite reinforced cover plates 1, each composite plate 4 and the composite connecting piece 6, and the two composite reinforced cover plates 1, each composite plate 4 and the composite connecting piece 6 are connected and fixed by the fiber bundle 3 in the connecting hole 2. In addition, the core layer of the hybrid connection structure of metal-free composite foam sandwich panels is a foam material, such as common polyurethane foam and polystyrene foam, which is light and has good heat insulation and sound insulation properties; the upper and lower surface layers are composite materials, such as carbon fiber reinforced composite materials (CFRP) or glass fiber reinforced composite materials (GFRP), which have high strength and corrosion resistance and can provide bearing capacity for the overall structure. The hybrid connection structure of metal-free composite foam sandwich panels in this application does not use metal materials, has good wave permeability, and will not cause electromagnetic shielding. It can be applied to scenarios in aviation, aerospace or ships where signal penetration is required.

[0020] The first direction is the same as the direction in which the groove 601 extends. The groove 601 of the composite material connector 6 may be a trapezoidal groove, which may accommodate the respective platforms 401 of the two opposite composite material plates 4. Figure 1 , Figure 1 Taking two relative composite panels 4 as an example, in order to increase the area of ​​the hybrid connection structure of the metal-free composite foam sandwich panels, a composite connector 6 can be used to connect multiple groups of first composite foam sandwich panels and multiple groups of second composite foam sandwich panels. The height of the platform 401 can be greater than or equal to the groove 601, so as to ensure that the platform 401 is in contact with the bottom surface of the groove 601, form a pressing force on the composite panel 4, and increase the stability of the hybrid connection structure of the metal-free composite foam sandwich panels. The cross-section of the two edges of the composite connector 6 can be rectangular, triangular, or other shapes. The shape of the cross-section matches the cross-section of the edge in the same direction of the composite foam sandwich 5, so as to increase the torque between the composite foam sandwich 5 and the composite connector 6, thereby increasing the strength of the hybrid connection structure of the metal-free composite foam sandwich panels. Two composite reinforced cover plates 1 are pressed on both sides of the multiple groups of first composite foam sandwich panels and the multiple groups of second composite foam sandwich panels, so that the strength of the hybrid connection structure of the metal-free composite foam sandwich panels can be increased through the composite connector 6 in the middle and the composite reinforced cover plates 1 on both sides. By connecting the composite reinforced cover plate 1, the composite plate 4 and the composite connector 6 through the fiber bundle 3, the strength of the hybrid connection structure of the metal-free composite foam sandwich panel can be further increased. In addition, compared with the traditional connection method between metal parts and the hybrid connection method with metal connectors in the prior art, the structure of the present invention is simple and easy to implement, and has the unique advantage of not containing any metal components, and the application environment and conditions are more diverse. Considering that the strength of a pure composite plate may be relatively small and there is a possibility of premature damage during use, the present application adopts a sandwich hybrid connection structure of a composite plate, a composite foam sandwich and a composite connector to increase the strength of the structure.

[0021] In an embodiment of the present application, the platform 401 is a right-angled trapezoidal platform, and the cross-section of the composite connector 6 along the second direction is a double spindle shape. Both sides of the double spindle shape have a groove 601, and both ends of the double spindle shape have two adjacent inclined surfaces, and the two adjacent inclined surfaces extend along the length direction of the groove 601. The inclined surface of the right-angled trapezoidal platform coincides with the inner edge of the groove 601, and the width of the bottom of the groove 601 along the second direction is a, and the minimum width of the platform 401 along the second direction is b, and the value of a is greater than or equal to twice b, wherein the first direction is perpendicular to the second direction.

[0022] Specifically, the two relative platforms 401 in the same groove 601 can be in close contact or have a gap in between. The advantage of close contact is that the strength is greater than that of non-close contact. However, when the strength requirement is not high, there can be a gap between the two relative platforms 401. This can save the material of the composite material plate 4 and thus save costs.

[0023] In the embodiment of the present application, a side of the composite foam core 5 close to the composite connecting piece 6 has a V-shaped groove 501 , and the V-shaped groove 501 matches two adjacent inclined surfaces on the same side of the composite connecting piece 6 .

[0024] like Figure 1 As shown, it is worth noting that the edges of the two platforms 401 of the upper and lower composite material connectors 6 can coincide with the groove 601 and contact the upper and lower vertices of the spindle shape, so that the triangular blocks at both ends of the composite material connector 6 with a spindle-shaped cross-section can fit tightly with the V-shaped groove 501, thereby limiting the activity space of the composite foam core 5 in its two adjacent composite material panels 4, thereby ensuring the stability of the structure.

[0025] In an embodiment of the present application, there are two groups of connecting holes 2, which are respectively located on both sides of the groove 601, and each group of connecting holes 2 is arranged along the extension direction of the groove 601. The two groups of connecting holes 2 respectively penetrate the respective platforms 401 of the multiple groups of first composite foam sandwich panels and the respective platforms 401 of the multiple groups of second composite foam sandwich panels.

[0026] Specifically, the connection holes 2 are located on both sides of the groove 601, and each group of connection holes 2 is arranged along the extension direction of the groove 601. The two groups of connection holes 2 respectively penetrate the platforms 401 of the multiple groups of first composite foam sandwich panels and the platforms 401 of the multiple groups of second composite foam sandwich panels. After the fiber bundles 3 are used to penetrate the connection holes 2, each composite reinforced cover plate 1, composite board 4 and composite connector 6 are fixed by the fiber bundles 3 between the connection holes 2, and then vacuum-assisted resin injection is used in each connection hole 2 for reinforcement molding. Vacuum-assisted molding is used to inject resin to eliminate pores and holes in the structure to improve the overall bearing capacity of the structure.

[0027] In the embodiment of the present application, the composite connector 6 is molded by short fiber reinforcement. The two composite reinforced cover plates 1, each composite plate 4 and the composite connector 6 are connected by the fiber bundle 3 between the connection holes 2, and each connection hole 2 is reinforced by vacuum-assisted injection resin. Each composite reinforced cover plate 1 and composite plate 4 are pultruded by long fiber glass and epoxy resin. The composite connector 6 is molded by short fiber glass and epoxy resin.

[0028] Specifically, the composite foam sandwich panel connecting piece is composed of a composite panel 4 and a composite foam sandwich 5, the composite connecting piece 6 is in a double spindle shape and is formed by short fiber reinforcement molding; the contact part of the double spindle-shaped composite connecting piece 6 and the composite foam sandwich panel is in the same shape, the two composite reinforced cover plates 1 and each composite panel 4 are formed by pultrusion of long fiber glass and epoxy resin; the composite connecting piece 6 is molded by short fiber glass and epoxy resin. The connection structure does not contain any metal structure, the technology is simple and feasible, and the practicability is strong.

[0029] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A hybrid connection structure of a metal-free composite foam sandwich panel, characterized in that: include: A composite material connecting piece (6), wherein two opposite side surfaces are symmetrically arranged about the center of the composite material connecting piece (6), and both the opposite side surfaces are provided with grooves (601), and the two grooves (601) are symmetrically arranged about the center of the composite material connecting piece (6); A plurality of groups of first composite foam sandwich panels, each group of the first composite foam sandwich panels comprising two composite panels (4) arranged opposite to each other and a composite foam sandwich (5) sandwiched between the two composite panels (4), each composite panel (4) having a platform (401) at the inner edge close to another composite panel (4), the two platforms (401) being respectively engaged in the two grooves (601), the composite foam sandwich (5) being matched and connected to the outer side surface of the composite connector (6), the plurality of groups of the first composite foam sandwich panels being arranged along a first direction, the first direction being the same as the direction in which the grooves (601) extend; A plurality of groups of second composite foam sandwich panels are arranged symmetrically with the plurality of groups of the first composite foam sandwich panels about the axis of the composite connector (6); Two composite material reinforced cover plates (1), each of the composite material reinforced cover plates (1) being arranged to cover the outer side surfaces of the plurality of groups of the first composite material foam sandwich panels and the plurality of groups of the second composite material foam sandwich panels on the same side; The connecting hole (2) passes through the two composite material reinforced cover plates (1), each of the composite material plates (4) and the composite material connecting piece (6), and the two composite material reinforced cover plates (1), each of the composite material plates (4) and the composite material connecting piece (6) are connected and fixed by the fiber bundle (3) in the connecting hole (2).

2. The hybrid connection structure of the metal-free composite foam sandwich panel according to claim 1, characterized in that: The platform (401) is a right-angled trapezoidal platform, the cross-section of the composite material connector (6) along the second direction is a double spindle shape, both sides of the double spindle shape have the groove (601), both ends of the double spindle shape have two adjacent inclined surfaces, the two adjacent inclined surfaces extend along the length direction of the groove (601), the inclined surface of the right-angled trapezoidal platform coincides with the inner edge of the groove (601), and the width of the bottom of the groove (601) along the second direction is a, the minimum width of the platform (401) along the second direction is b, and the value of a is greater than or equal to twice b, wherein the second direction is perpendicular to the first direction.

3. The hybrid connection structure of the metal-free composite foam sandwich panel according to claim 2, characterized in that: The composite foam core (5) has a V-shaped groove (501) on the side close to the composite connecting piece (6), and the V-shaped groove (501) matches two adjacent inclined surfaces on the same side of the composite connecting piece (6).

4. The hybrid connection structure of the metal-free composite foam sandwich panel according to claim 1, characterized in that: The connection holes (2) are in two groups, and the two groups of connection holes (2) are respectively located on both sides of the groove (601), and each group of connection holes (2) is arranged along the extension direction of the groove (601), and the two groups of connection holes (2) respectively penetrate the respective platforms (401) of the plurality of groups of the first composite foam sandwich panels and the respective platforms (401) of the plurality of groups of the second composite foam sandwich panels.

5. The hybrid connection structure of the metal-free composite foam sandwich panel according to claim 1, characterized in that: The composite material connecting piece (6) is formed by short fiber reinforcement compression molding.

6. The hybrid connection structure of the metal-free composite foam sandwich panel according to claim 1, characterized in that: The two composite material reinforced cover plates (1), each composite material plate (4) and the composite material connecting piece (6) are connected via a fiber bundle (3) between the connecting holes (2), and each connecting hole (2) is reinforced and formed by vacuum-assisted injection of resin.

7. The hybrid connection structure of the metal-free composite foam sandwich panel according to claim 1, characterized in that: The two composite material reinforced cover plates (1) and each composite material plate (4) are formed by pultrusion of long fiber glass and epoxy resin.

8. The hybrid connection structure of the metal-free composite foam sandwich panel according to claim 1, characterized in that: The composite material connecting piece (6) is formed by compression molding of short fiber glass and epoxy resin.

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