A CFRP-aluminum alloy box-type plate joint

Abstract

The present invention discloses a CFRP-aluminum alloy box-type plate node, including an aluminum alloy connecting rod member, an upper CFRP cover plate, a lower CFRP cover plate, an upper aluminum alloy cover plate, a lower aluminum alloy cover plate, a cylinder, a sleeve, a socket, a CFRP cable, an adhesive, a glass glue, an end plug, and a clamping block; The present invention uses two upper and lower CFRP cover plates as the intermediate layer to connect the aluminum alloy cover plate and the rod member, replacing the connection of the cover plate and the rod member with bolts in the traditional plate node. And it adopts the form of connecting the CFRP cable with the connecting rod member, so as to improve the situation of dispersed force among the connecting rod members in the traditional plate node. The connection method used in the present invention can effectively avoid the stress concentration phenomenon caused by bolt holes, improve the overall stability of the aluminum alloy connecting member and the aluminum alloy cover plate, and prevent the cracking of the member from reducing the bearing capacity. The present invention effectively avoids the notch effect caused by the sudden release of the extrusion stress at the small hole end by setting a straight section on the inner wall of the embedded socket of the connecting rod member.

Description

Technical Field

[0001] The present invention relates to the technical field of connection nodes, and particularly relates to a CFRP-aluminum alloy box-shaped plate node. Background Art

[0002] Single-layer spherical latticed shells have become a widely used structural form in large-span spatial structures due to their reasonable force-bearing and beautiful shape. Nodes are an important part of the latticed shell structure. Currently, the commonly used node form for single-layer spherical latticed shell structures in China is the plate node. However, the traditional plate node has a large number of bolts at the connection between the metal cover plate and each member, which is not conducive to construction. Moreover, stress concentration is likely to occur at the bolt holes, and the members are prone to break along the holes under external forces, resulting in the fracture of the ends of the connecting members and the failure of the node connection. In addition, the traditional plate node only relies on the metal cover plate to transfer bending moment and shear force, and there is no effective connection between the connecting members, so the overall force-bearing of the node is relatively weak. Therefore, on the basis of the traditional plate node, new materials and new connection methods are used to optimize the plate node to further improve the overall mechanical properties of the single-layer latticed shell structure.

[0003] Among them, carbon fiber reinforced polymer (CFRP for short) is very suitable for cable and prestressed structures due to its advantages such as light weight, high strength, corrosion resistance, small temperature deformation, and high tensile strength. The CFRP material has various shapes and a wide range of applications. It has sheet form, cable form, and member form. It can not only be used as a strengthening and renovation material in building structures, but also replace steel cables and be applied to large-span spatial structures.

[0004] In addition, aluminum alloy materials are also favored by more and more designers due to their unique advantages. First of all, aluminum alloy has a light self-weight and high strength. Using an aluminum alloy structure can effectively reduce the overall self-weight of the structure, reduce the load-bearing of the lower structure, and weaken the seismic action on the structure. Secondly, aluminum alloy has good corrosion resistance. Aluminum alloy can form a dense oxide film in the air and is suitable for large industrial buildings with high anti-corrosion requirements. Finally, aluminum alloy is easy to extrude and can be processed into profiles with relatively complex cross-sectional shapes to meet the requirements of building shapes.

[0005] In summary, combining the characteristics and advantages of the above two materials, on the premise of ensuring the safety, reliability, and feasibility of the structure, a CFRP-aluminum alloy box-shaped plate node is designed. Summary of the Invention

[0006] The purpose of the present invention is to provide a CFRP-aluminum alloy box-shaped plate node to solve the above problems.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A CFRP-aluminum alloy box-shaped plate node, comprising an aluminum alloy connecting rod, an upper CFRP cover plate, a lower CFRP cover plate, an upper aluminum alloy cover plate, a lower aluminum alloy cover plate, a cylinder, a sleeve, a socket, a CFRP cable, an adhesive, a glass glue, an end plug, and a clamping block; the upper and lower surfaces of the outer side of the aluminum alloy connecting rod are adhesively bonded to the upper CFRP cover plate and the lower CFRP cover plate respectively through an adhesive, a cylinder is vertically arranged between the upper CFRP cover plate and the lower CFRP cover plate, the upper CFRP cover plate is arranged at the top end of the cylinder, and the lower CFRP cover plate is arranged at the bottom end of the cylinder; the center lines of the cylinder along the length direction coincide with the center lines of the upper CFRP cover plate and the lower CFRP cover plate respectively; the upper CFRP cover plate and the lower CFRP cover plate are tightly connected to the cylinder through an adhesive.

[0009] On the other side of the upper and lower CFRP cover plates that are not adhesively bonded to the cylinder, they are respectively adhesively connected to the upper and lower aluminum alloy cover plates through an adhesive. The upper and lower CFRP cover plates and the upper and lower aluminum alloy cover plates are circular cover plates with the same diameter.

[0010] The aluminum alloy connecting rod is a box-shaped rod, and six connecting rods are evenly distributed around the upper CFRP cover plate, the lower CFRP cover plate, and the cylinder.

[0011] Further, both ends of the aluminum alloy connecting rod contain an embedded socket. The embedded socket is of a straight cylinder combined with an internal cone adhesive type, and the length accounts for 20% of the overall rod length. The inner wall of the socket is a straight section at the small hole end, and the length of the straight section accounts for 40% of the overall socket length. The remaining part of the inner wall except the straight section is wedge-shaped along the length direction of the connecting rod, and the diameter of the internal cone hole gradually increases.

[0012] Further, a metal sleeve is arranged inside the embedded socket for connecting with the CFRP cable. The CFRP cable is composed of 19 parallel rod cables and is arranged along the length direction of the connecting rod. The width of the metal sleeve is between the inner diameter of the socket and the outer diameter of the CFRP cable. The surface of the sleeve is ribbed and provided with a cutting slot. The opening shape of the cutting slot is wedge-shaped corresponding to the straight section of the inner wall of the socket and rectangular corresponding to the wedge section of the socket.

[0013] The cylinder is a hollow cylinder with side holes. There are six side holes of equal size. The centers of the side holes are respectively aligned with the centers of the holes of the embedded sockets at the ends of the connecting rods. The inner wall of the side holes of the cylinder is wedge-shaped and contains a straight soft metal sleeve. The CFRP cable passes through the soft metal sleeve and is connected to the cylinder. One end of the cylinder close to the connecting rod is a small hole, and the end close to the hollow of the cylinder is a large hole. End plugs are used to fix the parallel strands of the CFRP cable at both the large hole end and the small hole end.

[0014] The end of the CFRP cable-connected cylinder uses a wedge-shaped clamp and an adhesive to form a composite anchorage. The contact surface between the wedge-shaped clamp and the soft metal sleeve is roughened, and the contact surface with the inner wall of the cylinder is made smooth. The end of the CFRP cable connecting rod is provided with an end plug and sealed with glass glue.

[0015] After the CFRP cable is cut, the CFRP strands are polished with sandpaper to increase the interfacial bonding performance. The adhesive should preferably be a high-performance epoxy resin.

[0016] A connection method for a CFRP-aluminum alloy box-shaped plate node includes the following steps:

[0017] (a) Position and paste six connecting rods on the lower CFRP cover plate, and paste the lower aluminum alloy cover plate on the other side of the lower CFRP cover plate;

[0018] (b) Paste and fix the multi-side hole hollow cylinder at the center of the lower CFRP cover plate, and align the side holes with the six connecting rods;

[0019] (c) Connect the hollow cylinder with a CFRP cable through a metal sleeve, and fix one end of the CFRP cable connected to the cylinder through a clamp, an end plug, an adhesive and glass glue;

[0020] (d) Pass the CFRP cable through the metal sleeve and connect it to the rod, and fix it with an end plug, glass glue and an adhesive;

[0021] (e) Fix the upper surface of the upper CFRP cover plate and the six connecting rods with an adhesive, and fix the other side of the upper CFRP cover plate to the upper aluminum alloy cover plate with an adhesive.

[0022] The order of steps (a) and (b) can be exchanged.

[0023] The end plugs in steps (c) and (d) are provided at the large hole end and the small hole end, which play the role of fixing the strands and accurate positioning, and the end plugs can fall off.

[0024] The present invention uses two upper and lower CFRP cover plates as the intermediate layer to connect the aluminum alloy cover plate and the rod, replacing the connection of the cover plate and the rod with bolts in the traditional plate node. And it adopts the form of connecting the CFRP cable with the connecting rod, so as to improve the situation of force dispersion between the connecting rods of the traditional plate node. The connection method used in the present invention can effectively avoid the stress concentration phenomenon caused by bolt holes, improve the overall stability of the aluminum alloy connecting member and the aluminum alloy cover plate, and prevent the component from cracking and reducing the bearing capacity.

[0025] Compared with the existing plate node types and node connection technologies, the beneficial effects of the present invention are specifically as follows:

[0026] 1. By using a CFRP cover plate as the intermediate layer between the connecting rod members and the aluminum alloy cover plate, the overall stability of the connecting rod members and the cover plate in the joint area is greatly improved. Compared with traditional plate joints, the bearing capacity of the joint is increased, the processing cost is saved, and the construction speed is accelerated.

[0027] 2. At the center of the joint area, by setting a cylinder between the upper CFRP cover plate and the lower CFRP cover plate, the connection between the upper and lower cover plates is strengthened, and the shear bearing capacity at the joint connection is improved.

[0028] 3. The aluminum alloy box-shaped connecting rod members and the hollow cylindrical body with side holes are connected by CFRP cables. Compared with the discontinuous arrangement form of each connecting rod member in the traditional plate joint and only relying on the upper and lower cover plates to transfer bending moment and shear force, the present invention uses the form of CFRP cables to transfer the bending moment and shear force received by the joint under external force to the connecting rod members to bear the force together, effectively avoiding the situation of excessive concentrated force on the upper and lower cover plates resulting in fracture, and the overall safety of the joint is higher.

[0029] 4. In the present invention, by setting a straight section on the inner wall of the embedded sleeve of the connecting rod member, the notch effect caused by the sudden release of extrusion stress at the small hole end is effectively avoided. At the same time, the present invention proposes a new type of ribbed slotted sleeve form. On the one hand, it can be better embedded in the bonding medium to make the sleeve and the adhesive fit more closely together to bear the force together. On the other hand, the variable cross-section cutting seam width setting can control the process of the radial extrusion force transmitting inward. The ribbed metal sleeve can increase the contact area between the sleeve and the adhesive medium and better play the anchoring role.

[0030] 5. The box-shaped connecting rod member of the present invention is connected to the cylinder by a CFRP cable. There is no contact between the connecting rod member and the cylinder, allowing a small range of errors, facilitating construction, having stronger practicability, and effectively improving the energy dissipation capacity of the joint under seismic action.

[0031] 6. The end of the connecting rod member of the present invention is not welded, which can avoid the reduction of the strength of the aluminum alloy member caused by welding and simplify the construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of the present invention.

[0033] Figure 2 It is a schematic diagram without a cover plate.

[0034] Figure 3 It is a schematic diagram of a hollow cylinder with side holes.

[0035] Figure 4 It is a schematic diagram of a soft metal sleeve.

[0036] Figure 5 It is a schematic cross-sectional diagram of the side hole of the cylinder.

[0037] Figure 6 Schematic diagram of a hollow cylinder with side holes for CFRP cable connection belt

[0038] Figure 7 Schematic diagram of an aluminum alloy connecting rod

[0039] Figure 8 Schematic diagram of the sleeve cross-section

[0040] Figure 9 Schematic diagram of a ribbed slotted metal casing

[0041] Figure 10 Schematic diagram of CFRP cable connecting aluminum alloy rod

[0042] Figure 11 Schematic diagram of CFRP cable Specific implementation mode

[0043] The following further illustrates the present invention in conjunction with embodiments. It can be known that these embodiments are only used to explain the present invention and are not used to limit the present invention.

[0044] Combined with the attached Figure 1 This embodiment of a CFRP-aluminum alloy box-type plate node includes an aluminum alloy box-type connecting rod member (1), an upper aluminum alloy cover plate (2), a lower aluminum alloy cover plate (3), an upper CFRP cover plate (4), a lower CFRP cover plate (5), and a multi-side-hole hollow cylinder (6). The connecting rod member (1) is adhesively installed between the upper and lower CFRP cover plates and is evenly distributed around the cylinder (6) at equal angles. One side of the upper CFRP cover plate (4) is connected to the upper surfaces of six connecting rod members (1) through an adhesive (11), and the other side is connected to the upper aluminum alloy cover plate (2) through the adhesive (11). One side of the lower CFRP cover plate (5) is connected to the lower surfaces of six connecting rod members (1) through the adhesive (11), and the other side is connected to the lower aluminum alloy cover plate (3) through the adhesive (11). The center of the hollow part of the cylinder (6) is aligned with the centers of the upper CFRP cover plate (4) and the lower CFRP cover plate (5).

[0045] Combined with the attached Figure 3 ~Attached Figure 5 In this embodiment, the multi-side-hole hollow cylinder (6) is placed between the upper and lower CFRP cover plates. The side hole wall of the cylinder (6) is smooth and wedge-shaped, and the inner cone angle is 2°. Among them, the side close to the connecting rod member (1) is the loading end, and the side close to the hollow part of the cylinder is the free end. The CFRP cable (8) passes through the soft metal casing (10), and the soft metal casing (10) is adhesively bonded to the inside of the side hole of the cylinder (6) through an adhesive (11).

[0046] In this embodiment, the wedge-shaped clamping block (12) is used to anchor the CFRP cable (8) at the free end of the cylindrical side hole. At the cylindrical side hole, the compressive stress is transmitted to the wedge-shaped clamping block and distributed on the surface of the metal sleeve. Then, the pressure is transmitted to the CFRP cable (8) through the metal sleeve, thereby reducing the concentrated compressive stress borne by the CFRP cable. At the same time, the outer surface of the roughened soft metal sleeve (10) and the inner surface of the wedge-shaped clamping block (12) are adopted, so that sufficient friction can be generated at the contact between the soft metal sleeve and the clamping block to prevent the slip of the CFRP cable. When the CFRP cable (8) is subjected to an external tensile force, the wedging effect of the wedge block generates a mechanical biting force to balance the external load of the CFRP cable (8). The material of the soft metal sleeve (10) can be an aluminum sleeve or a copper sleeve, and the material of the wedge-shaped clamping block (12) can be a steel wedge-shaped clamping block. Considering the protection of the CFRP cable (8) and the construction cost comprehensively, the length of the two ends of the soft metal sleeve (10) exposed outside the wedge-shaped clamping block (12) is 2 - 5 cm.

[0047] Combined with the attached Figure 6 ~ attached Figure 9 , both ends of the connecting rod member (1) are provided with embedded sleeves (7). The inner wall of the embedded sleeve (7) is composed of a straight cylinder section and an inner cone section, accounting for 40% and 60% of the overall sleeve length at both ends respectively, and the inner cone angle is 2° - 4°. The direction close to the cylinder (6) is the loading end, which is in a straight cylinder shape, and the direction along the length of the connecting rod member (1) is the free end, which is in a wedge shape.

[0048] In this embodiment, the CFRP cable (8) passes through the ribbed slotted sleeve (9) and is bonded to the embedded sleeve (7) through an adhesive (11). The diameter of the ribbed slotted sleeve (9) is between the inner diameter of the sleeve and the outer diameter of the CFRP cable. The outer surface is roughened and provided with ribbed stripes. The opening shape of the cutting slot is wedge-shaped corresponding to the straight section of the inner wall of the sleeve (7), and rectangular corresponding to the wedge section of the sleeve (7). The cutting slot of the ribbed slotted sleeve (9) has the largest width at the large hole end of the sleeve (7), and the width of the cutting slot gradually decreases to zero at the small hole end of the sleeve (7). Such a setting can better resist the inward transmission of excessive radial pressure at the small hole end, and enable the sleeve (9) and the adhesive (11) to be better bonded at the large hole end.

[0049] Although the preferred examples of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific implementation methods. The above specific implementation methods are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can make more forms without departing from the idea, purpose and scope protected by the claims of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A CFRP-aluminum alloy box-shaped plate node, characterized in that, It includes aluminum alloy connecting rods, upper CFRP cover plates, lower CFRP cover plates, upper aluminum alloy cover plates, lower aluminum alloy cover plates, cylinders, sleeves, sleeves, CFRP cables, adhesives, glass adhesives, end plugs, and clamping blocks; The upper and lower surfaces of the outer side of the aluminum alloy connecting rod are adhesively bonded to the upper CFRP cover plate and the lower CFRP cover plate respectively through an adhesive. A cylinder is vertically arranged between the upper CFRP cover plate and the lower CFRP cover plate. The upper CFRP cover plate is arranged at the top end of the cylinder, and the lower CFRP cover plate is arranged at the bottom end of the cylinder; the center line of the cylinder along the length direction coincides with the center lines of the upper CFRP cover plate and the lower CFRP cover plate respectively; the upper CFRP cover plate and the lower CFRP cover plate are firmly connected to the cylinder through an adhesive; both ends of the aluminum alloy connecting rod contain embedded sleeves, and a metal sleeve is arranged inside the embedded sleeve for connecting with the CFRP cable; the aluminum alloy connecting rod is a box-shaped rod; On the other side of the upper CFRP cover plate and the lower CFRP cover plate that are not adhesively bonded to the cylinder, they are respectively adhesively bonded to the upper aluminum alloy cover plate and the lower aluminum alloy cover plate through an adhesive. The upper and lower CFRP cover plates and the upper and lower aluminum alloy cover plates are circular cover plates with the same diameter; an end plug is provided at the end of the CFRP cable connecting rod and is sealed with a glass adhesive; the end of the CFRP cable connecting the cylinder is combined with a wedge-shaped clamping block and an adhesive to form a composite anchorage; The embedded sleeve is of a straight cylinder combined with an inner cone pasting type, and its length accounts for 20% of the overall rod length. The inner wall of the sleeve is a straight section at the small hole end, and the length of the straight section accounts for 40% of the overall sleeve length. The remaining part of the inner wall except the straight section is wedge-shaped along the length direction of the connecting rod, and the diameter of the inner cone hole gradually increases from small to large.

2. The CFRP-aluminum alloy box-type plate joint according to claim 1, wherein Six connecting rods are evenly distributed around the upper CFRP cover plate, the lower CFRP cover plate, and the cylinder.

3. The CFRP-aluminum alloy box-shaped plate node according to claim 1, characterized in that, The CFRP cable is composed of multiple parallel rod cables and is arranged along the length direction of the connecting rod. The width of the metal sleeve is between the inner diameter of the sleeve and the outer diameter of the CFRP cable. The surface of the sleeve is ribbed and provided with a cutting seam. The opening shape of the cutting seam is wedge-shaped corresponding to the straight section of the inner wall of the sleeve and rectangular corresponding to the wedge-shaped section of the sleeve.

4. A CFRP-aluminum alloy box-shaped plate node according to claim 1, characterized in that, The cylinder is a hollow cylinder with side holes. There are six side holes of the same size. The centers of the side holes are respectively aligned with the centers of the holes of the embedded sleeves at the ends of the connecting rods. The inner wall of the side holes of the cylinder is wedge-shaped and contains a straight soft metal sleeve. The CFRP cable passes through the soft metal sleeve and is connected to the cylinder; one end of the cylinder close to the connecting rod is a small hole, and the end close to the hollow of the cylinder is a large hole. End plugs are used to fix the parallel strands of the CFRP cable at both the large hole end and the small hole end.

5. A CFRP-aluminum alloy box-shaped plate node according to claim 1, characterized in that, The contact surface between the wedge-shaped clamping block and the soft metal sleeve is roughened, and the contact surface with the inner wall of the cylinder is made smooth.

6. The CFRP-aluminum alloy box-shaped plate node according to claim 1, characterized in that, After the CFRP cable is cut, the CFRP strands are polished with sandpaper to increase the interfacial bonding performance.

7. A CFRP-aluminum alloy box-type plate node according to claim 1, characterized in that, The adhesive uses a high-performance epoxy resin.

8. A connection method for implementing the CFRP-aluminum alloy box-plate joint as described in any one of claims 1-7, characterized in that, It includes the following steps: (a) Position and paste six connecting rods on the lower CFRP cover plate, and paste the lower aluminum alloy cover plate on the other side of the lower CFRP cover plate; (b) Paste and fix the multi-side-hole hollow cylinder at the center of the lower CFRP cover plate, and align the side holes with the six connecting rods; (c) Connect the hollow cylinder with CFRP cables through metal sleeves, and fix one end of the CFRP cables connected to the cylinder by clamping blocks, end plugs, adhesives and glass glue; (d) Pass the CFRP cables through the metal sleeves to connect with the rods, and fix them with end plugs, glass glue and adhesives; (e) Fix the upper surface of the upper CFRP cover plate and the six connecting rods with adhesives, and fix the other side of the upper CFRP cover plate with the upper aluminum alloy cover plate through adhesives.

9. The connection method of the CFRP-aluminum alloy box girder plate joint according to claim 8, characterized in that, Exchange the order of steps (a) and (b); In steps (c) and (d), the end plugs are provided at the large-hole end and the small-hole end, which play the role of fixing the wire strands and accurate positioning, and the end plugs can fall off.

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