Flange connection structure of composite thin-walled pipe and forming device and method

Abstract

The present application relates to the technical field of pipe connection, in particular to a composite thin-walled pipe flange connection structure, a forming device and a forming method, the connection structure comprising a composite thin-walled pipe and a flange assembly; the composite thin-walled pipe is integrally formed with a flange at both ends; a through hole is arranged on the flange; the flange assembly comprises a first flange fixedly connected with the inner side of the flange and a second flange fixedly connected with the outer side of the flange; the diameter of the flange hole of the first flange is the same as the outer diameter of the composite thin-walled pipe. The number of the through hole, the first bolt hole arranged on the first flange and the second bolt hole arranged on the second flange is the same and one-to-one corresponding. The composite thin-walled pipe flange connection structure has large bonding strength, high connection precision and can realize high-precision connection between two composite thin-walled pipes with different diameters.

Description

Technical Field

[0001] This invention relates to the field of pipe connection technology, and in particular to a composite material thin-walled pipe flange connection structure, forming device and method. Background Technology

[0002] Composite material thin-walled tubes possess advantages such as lightweight, high load-bearing capacity, high stiffness, and high strength, and are widely used in fields such as electronics, rail transportation, and aerospace. However, due to their thin walls and large length-to-diameter ratio, these tubes cannot undergo complex machining after structural molding, and the strength of the connection with flanges cannot be guaranteed, leading to unstable connections between pipes, low concentricity, and consequently affecting connection accuracy. Chinese patent CN217843048 U discloses a butt joint structure for carbon fiber tubes, requiring the installation of a ring and hook structure inside the carbon fiber tube. For thin-walled carbon fiber tubes with small inner diameters, the molding process is complex, and the strength and molding accuracy of the ring cannot be guaranteed. Chinese patent CN113202849 A discloses a carbon fiber tube and metal joint adhesive connection structure and metal joint, requiring the installation of an adhesive injection port on the carbon fiber tube body, which damages the fiber structure, resulting in discontinuous structure and affecting the strength of the carbon fiber tube.

[0003] Therefore, there is an urgent need to provide a composite material thin-walled pipe flange connection structure that has high bonding strength, high connection accuracy, and does not damage the continuity of fiber structure. Summary of the Invention

[0004] To address one or more technical problems in the prior art, the present invention provides a composite material thin-walled pipe flange connection structure, forming device, and method. This composite material thin-walled pipe flange connection structure has high bonding strength and high connection accuracy, does not require disruption of fiber structure continuity, and can achieve high-precision connection between two composite material thin-walled pipes of different diameters.

[0005] The present invention provides a composite material thin-walled tube flange connection structure in a first aspect, comprising a composite material thin-walled tube 1 and a flange assembly 2;

[0006] Both ends of the composite material thin-walled tube 1 are integrally formed with flanges 11; through holes are provided on the flanges 11;

[0007] Flange assembly 2 includes a first flange 21 that is sleeved on the composite thin-walled tube 1 and fixedly connected to the inner side of the flange 11, and a second flange 22 that is fixedly connected to the outer side of the flange 11;

[0008] The diameter of the flange hole of the first flange 21 is the same as the outer diameter of the composite thin-walled tube 1.

[0009] The number of through holes is the same as the number of first bolt holes 212 provided on the first flange 21 and the number of second bolt holes 222 provided on the second flange 22, and their positions correspond one-to-one.

[0010] In a second aspect, the present invention provides an apparatus for molding a composite material thin-walled pipe flange connection structure of the first aspect, the apparatus comprising a support 3 and a fastener 4;

[0011] The support member 3 includes two support bases 31 and a plurality of support columns 32 located between the two support bases 31;

[0012] The support base 31 is provided with a U-shaped slot 311 and a plurality of evenly distributed positioning holes 312;

[0013] U-shaped slot 311 is used to position composite material thin-walled tube 1;

[0014] The fastener 4 is provided with a plurality of evenly distributed positioning pins 42;

[0015] The locating pin 42 is inserted into the locating hole 312 to locate the flange assembly 2.

[0016] The present invention provides, in a third aspect, a method for forming a composite material thin-walled pipe flange connection structure as described in the first aspect, the method being implemented using the apparatus of the second aspect, the method comprising the following steps:

[0017] The composite thin-walled tube 1 is subjected to flanging and drilling to form a flanged 11 with through holes;

[0018] The tube body of the composite thin-walled tube 1 is placed in the U-shaped groove 311 to position the composite thin-walled tube 1.

[0019] Adhesive is applied to the surfaces of the flange 11, the first flange 21, and the second flange 22 of the composite thin-walled tube 1;

[0020] Insert the locating pin 42 into the locating hole 312 to locate the flange assembly 2, thereby improving the connection accuracy of the composite material thin-walled pipe flange connection structure.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] The composite material thin-walled tube flange connection structure provided by this invention features integrally formed flanges at both ends of the composite material thin-walled tube, ensuring the continuity of the fiber structure. This increases the bonding area between the composite material thin-walled tube and the flange assembly without affecting the tube's strength, thereby improving bond strength and reducing stress concentration. This connection structure offers high strength and precision between the composite material thin-walled tube and the flange assembly, solving the problems of low connection strength and poor forming precision between existing composite material thin-walled tubes and flange assemblies, as well as between different composite material thin-walled tubes. Furthermore, the coordinated arrangement of the first and second flanges ensures the perpendicularity and concentricity of the flange and the composite material thin-walled tube, enabling high-precision connections between composite material thin-walled tubes of different diameters.

[0023] The device for molding composite thin-walled tube flange connection structures provided by this invention includes a support member and a fixing member. The support member includes two support bases and multiple support columns located between the two support bases. The support bases are provided with U-shaped grooves and multiple evenly distributed positioning holes. The support columns play a supporting role during the molding process of the composite thin-walled tube flange connection structure, which can prevent the strength of the composite thin-walled tube body from being affected during the bonding process. The U-shaped grooves are used to position the composite thin-walled tube. The fixing member is provided with multiple evenly distributed positioning pins. The positioning pins are inserted into the positioning holes to position the flange assembly. This device can simultaneously position and press the composite thin-walled tube and the flange assembly during the molding process of the composite thin-walled tube flange connection structure, ensuring the perpendicularity and concentricity of the composite thin-walled tube and the flange assembly, and improving the bonding strength between the composite thin-walled tube and the flange assembly.

[0024] This invention provides a method for molding a composite thin-walled tube flange connection structure. By flanging the composite thin-walled tube to form a flange, the continuity of the fiber structure can be ensured. Without affecting the strength of the composite thin-walled tube body, the bonding area between the composite thin-walled tube and the flange assembly is increased, stress concentration is reduced, and the bonding strength between the composite thin-walled tube and the flange assembly is improved. During the bonding process, support and fixing components are used to position and tighten the composite thin-walled tube and the flange assembly, ensuring the perpendicularity and concentricity of the composite thin-walled tube and the flange assembly, as well as the bonding strength and accuracy between them. This molding method can effectively improve the bonding strength and connection accuracy of the composite thin-walled tube and the flange assembly, and has strong applicability, applicable to various connections between composite thin-walled tubes and flanges. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a composite material thin-walled tube provided by the present invention;

[0027] Figure 2 This is a schematic diagram of a composite material thin-walled pipe flange connection structure provided by the present invention;

[0028] Figure 3 This is a schematic diagram of the composite thin-walled tube, flange assembly, and support components during the molding process of a composite thin-walled tube flange connection structure provided by the present invention;

[0029] Figure 4 This is a structural schematic diagram of a fastener provided by the present invention;

[0030] Figure 5 This is a schematic diagram of the composite thin-walled tube, flange assembly, support and fasteners in the molding process of a composite thin-walled tube flange connection structure provided by the present invention.

[0031] Figure label:

[0032] 1-Composite thin-walled tube; 11-Flanged edge;

[0033] 21-First flange; 212-First bolt hole;

[0034] 22-Second flange; 221-Second flange hole; 222-Second bolt hole;

[0035] 3-Support component; 31-Support base; 311-U-shaped slot; 312-Positioning hole; 313-Third bolt hole; 32-Support column;

[0036] 4-Fixing component; 41-Circular groove; 42-Positioning pin; 43-Fourth bolt hole. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] In the description of the embodiments of the present invention, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple sets" refers to two or more sets; the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0039] In this specification, it should be understood that the directional terms such as "upper" and "lower" used in the description of the embodiments of the present invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of the present invention. Furthermore, in the context, it should also be understood that when it is mentioned that one element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0040] like Figure 1-2 The present invention provides a composite material thin-walled pipe flange connection structure, the connection structure including a composite material thin-walled pipe 1 and a flange assembly 2;

[0041] Both ends of the composite material thin-walled tube 1 are integrally formed with flanges 11; through holes are provided on the flanges 11;

[0042] Flange assembly 2 includes a first flange 21 that is sleeved on the composite thin-walled tube 1 and fixedly connected to the inner side of the flange 11, and a second flange 22 that is fixedly connected to the outer side of the flange 11;

[0043] The diameter of the flange hole of the first flange 21 is the same as the outer diameter of the composite thin-walled tube 1.

[0044] The number of through holes is the same as the number of first bolt holes 212 provided on the first flange 21 and the number of second bolt holes 222 provided on the second flange 22, and their positions correspond one-to-one.

[0045] It should be noted that "inner side" refers to the side of the flange closest to the composite thin-walled tube body; "outer side" refers to the side of the flange furthest from the composite thin-walled tube body. The composite thin-walled tube of this invention is a thin-walled tube made using resin as the matrix material and fiber as the reinforcing material, manufactured through a vacuum flow process. The fiber can be, but is not limited to, glass fiber, carbon fiber, and quartz fiber; the resin can be, but is not limited to, epoxy resin, unsaturated polyester resin, polyimide resin, bismaleimide resin, and cyanate ester resin. The flange assembly can be, but is not limited to, metal flanges, glass fiber composite flanges, carbon fiber composite flanges, etc.

[0046] The composite material thin-walled tube flange connection structure provided by this invention features integrally formed flanges at both ends of the composite material thin-walled tube, ensuring the continuity of the fiber structure. This increases the bonding area between the composite material thin-walled tube and the flange assembly without affecting the tube's strength, thereby improving bond strength and reducing stress concentration. This connection structure offers high strength and precision between the composite material thin-walled tube and the flange assembly, solving the problems of low connection strength and poor forming precision between existing composite material thin-walled tubes and flange assemblies, as well as between different composite material thin-walled tubes. Furthermore, the coordinated arrangement of the first and second flanges ensures the perpendicularity and concentricity of the flange assembly and the composite material thin-walled tube, enabling high-precision connections between composite material thin-walled tubes of different diameters.

[0047] It should be noted that in the process of connecting composite thin-walled pipes of different diameters, the two pipes are connected by passing bolts through the first bolt holes provided on the first flange and the second bolt holes provided on the second flange.

[0048] In some embodiments of the present invention, the wall thickness of the composite material thin-walled tube 1 is 0.2 to 0.8 mm, and the wall thickness of the composite material thin-walled tube of the present invention can be any value from 0.2 to 0.8 mm.

[0049] In some embodiments of the present invention, the flange 11 includes a plurality of folded portions evenly distributed along the circumference; through holes are provided on the folded portions and are evenly distributed along the circumference.

[0050] In some embodiments of the present invention, the number n of folds and the radius R of the composite material thin-walled tube 1 satisfy the following relationship:

[0051] When R≤40mm, 1≤R / n≤1.5;

[0052] When 40 < R ≤ 200 mm, 1.5 < R / n ≤ 2.5;

[0053] When R > 200 mm, 2.5 < R / n ≤ 3.

[0054] The number of folds in this invention is adjusted according to the radius R of the composite thin-walled tube to ensure that the strength of the composite thin-walled tube body is not affected during the formation of the folds.

[0055] like Figure 3-5 The present invention provides, in two aspects, an apparatus for forming a composite material thin-walled pipe flange connection structure of the first aspect; the apparatus includes a support member 3 and a fixing member 4;

[0056] The support member 3 includes two support bases 31 and a plurality of support columns 32 located between the two support bases 31;

[0057] The support base 31 is provided with a U-shaped slot 311 and a plurality of evenly distributed positioning holes 312;

[0058] U-shaped slot 311 is used to position composite material thin-walled tube 1;

[0059] The fastener 4 is provided with a plurality of evenly distributed positioning pins 42;

[0060] The locating pin 42 is inserted into the locating hole 312 to locate the flange assembly 2.

[0061] The device for molding composite thin-walled tube flange connection structures provided by this invention includes a support member and a fixing member. The support member includes two support bases and multiple support columns located between the two support bases. The support bases are provided with U-shaped grooves and multiple evenly distributed positioning holes. The support columns play a supporting role during the molding process of the composite thin-walled tube flange connection structure, which can prevent the strength of the composite thin-walled tube body from being affected during the bonding process. The U-shaped grooves are used to position the composite thin-walled tube. The fixing member is provided with multiple evenly distributed positioning pins. The positioning pins are inserted into the positioning holes to position the flange assembly. This device can simultaneously position and press the composite thin-walled tube and the flange assembly during the molding process of the composite thin-walled tube flange connection structure, ensuring the perpendicularity and concentricity of the composite thin-walled tube and the flange assembly, and improving the bonding strength between the composite thin-walled tube and the flange assembly.

[0062] The device also includes a third bolt hole 313 on the support member 3 and a fourth bolt hole 43 on the fastener 4; the third bolt hole 313 and the fourth bolt hole 43 are connected by bolts to press the composite thin-walled tube 1 and the flange assembly 2 together, so as to further improve the bonding strength and accuracy of the composite thin-walled tube 1 and the flange assembly 2 during the molding process.

[0063] It should be noted that during the insertion of the locating pin 42 into the locating hole 312, the locating pin 42 passes through the second bolt hole 222, the through hole, the first bolt hole 212, and the locating hole 312 in sequence to ensure that the flange assembly 2 and the composite material thin-walled tube 1 are concentrically aligned. The number of locating pins 42, locating holes 312, through holes, the first bolt hole 212, and the second bolt hole 222 are the same, and their positions correspond one-to-one.

[0064] The present invention does not specifically limit the dimensions of the support and fixing components, which can be adjusted according to the dimensions of the flange assembly 2.

[0065] In some embodiments of the present invention, the plurality of support columns 32 are symmetrically distributed; and / or

[0066] The width of the U-shaped groove 311 is not less than the outer diameter of the composite thin-walled tube 1.

[0067] The symmetrical distribution of multiple support columns 32 ensures uniform stress distribution during the molding process of the composite thin-walled tube flange connection structure, thereby improving connection accuracy. A U-shaped groove is provided on the support base 31 to position the composite thin-walled tube 1, and also facilitates its removal after molding.

[0068] In some embodiments of the present invention, a circular groove 41 with the same diameter as the first flange 21 and the second flange 22 is provided in the middle of the fastener 4;

[0069] The circular groove 41 is used to accommodate the flange assembly 2; the depth of the groove is equal to the thickness of the flange assembly 2. It should be noted that the thickness of the flange assembly 2 here refers to the distance between the inner surface of the first flange 21 and the outer surface of the second flange 22. The inner surface refers to the surface of the first flange 21 that is close to the pipe body of the composite thin-walled tube 1; the outer surface refers to the surface of the flange 11 that is away from the pipe body of the composite thin-walled tube 1.

[0070] The fastener 4 has a circular groove 41 in the middle for accommodating the flange assembly 2, the first flange 21, and the second flange 22. The groove has the same diameter and the same depth as the flange assembly 2. This ensures the positioning accuracy of the composite thin-walled tube and the flange assembly 2, and improves the bonding strength and accuracy of the flange structure of the composite thin-walled tube 1 during the molding process.

[0071] In some embodiments of the present invention, the positioning pins 42 are evenly distributed circumferentially inside the circular grooves 41, and the number of them is the same as that of the positioning holes 312 and their positions correspond one-to-one.

[0072] The present invention provides, in a third aspect, a method for forming a composite material thin-walled pipe flange connection structure as described in the first aspect, the method being implemented using the apparatus of the second aspect, the method comprising the following steps:

[0073] The composite thin-walled tube 1 is subjected to flanging and drilling to form a flanged 11 with through holes;

[0074] The tube body of the composite thin-walled tube 1 is placed in the U-shaped groove 311 to position the composite thin-walled tube 1.

[0075] Adhesive is applied to the surfaces of the flange 11, the first flange 21, and the second flange 22 of the composite thin-walled tube 1;

[0076] Insert the locating pin 42 into the locating hole 312 to locate the flange assembly 2, thereby improving the connection accuracy of the composite material thin-walled pipe flange connection structure.

[0077] The present invention first performs flanging and drilling on the composite thin-walled tube to form a flanged edge with through holes; then the composite thin-walled tube is placed in a U-shaped groove to position the composite thin-walled tube; adhesive is applied to the flanged edge of the composite thin-walled tube, the surface of the first flange and the second flange; finally, a positioning pin is inserted into the positioning hole to align the flange assembly and the composite thin-walled tube, thereby improving the connection accuracy of the composite thin-walled tube flange connection structure.

[0078] This invention provides a method for forming a flange connection structure for composite thin-walled tubes. By flanging the composite thin-walled tube to form a flange, the continuity of the fiber structure can be ensured. Without affecting the strength of the composite thin-walled tube body, the bonding area between the composite thin-walled tube and the flange assembly is increased, stress concentration is reduced, and the bonding strength between the composite thin-walled tube and the flange assembly is improved. During the bonding process, support and fixing components are used to position and tighten the composite thin-walled tube and the flange assembly, ensuring the perpendicularity and concentricity of the composite thin-walled tube and the flange assembly, as well as the bonding strength and accuracy between them. This method can effectively improve the bonding strength and connection accuracy of composite thin-walled tubes and flange assemblies, has strong applicability, and can be used for various connections between composite thin-walled tubes and flanges.

[0079] In some embodiments of the present invention, the flanging process includes dividing the opening of the composite thin-walled tube 1 into multiple parts, and then folding each part outward while the composite thin-walled tube is in a ductile state to form a flanged edge 11. It should be noted that the present invention places the composite thin-walled tube at a certain temperature to make it in a ductile state for folding; the present invention does not specifically limit the specific temperature, as long as it satisfies the requirement that the composite thin-walled tube is in a ductile state suitable for folding, and can be adjusted according to the different matrix materials of the composite thin-walled tube.

[0080] In a specific embodiment of the present invention, the first flange 21 is first fitted onto the composite thin-walled tube 1, and the opening of the composite thin-walled tube 1 is divided into multiple parts. When the composite thin-walled tube 1 is in a tough state, each part is folded outward to form a flange 11 containing multiple folded parts. Then, holes are punched in the folded parts to obtain a flange 11 with through holes. Then, the composite thin-walled tube 1 is placed in the U-shaped groove 311, and adhesive is applied to the surface of the flange 11, the first flange 21, and the second flange 22 of the composite thin-walled tube 1. Then, the positioning pin 42 is passed through the second bolt hole 222, the through hole, the first bolt hole 212, and the positioning hole 312 in sequence, so that the composite thin-walled tube 1 and the flange assembly 2 can be better aligned. Finally, the third bolt hole 313 provided on the support base 31 and the fourth bolt hole 43 provided on the fastener 4 are connected by bolts, which further improves the bonding strength and accuracy of the composite thin-walled tube flange connection structure forming process.

[0081] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An apparatus for molding composite material thin-walled pipe flange connection structures, characterized in that, The device includes a support (3) and a fixing member (4); The support member (3) includes two support bases (31) and a plurality of support columns (32) located between the two support bases (31). The support base (31) is provided with a U-shaped slot (311) and a plurality of evenly distributed positioning holes (312). The U-shaped groove (311) is used to position the composite material thin-walled tube (1). The fastener (4) is provided with a plurality of evenly distributed positioning pins (42). The positioning pin (42) is inserted into the positioning hole (312) to position the flange assembly (2) of the composite material thin-walled pipe flange connection structure. The connection structure includes a composite material thin-walled tube (1) and a flange assembly (2); Both ends of the composite material thin-walled tube (1) are integrally formed with flanges (11); the flanges (11) are provided with through holes; The flange assembly (2) includes a first flange (21) sleeved on the composite thin-walled tube (1) and fixedly connected to the inside of the flange (11) and a second flange (22) fixedly connected to the outside of the flange (11). The diameter of the flange hole of the first flange (21) is the same as the outer diameter of the composite thin-walled tube (1); The number of through holes is the same as the number of the first bolt holes (212) provided on the first flange (21) and the number of the second bolt holes (222) provided on the second flange (22), and their positions correspond one-to-one.

2. The apparatus according to claim 1, characterized in that, The plurality of the support columns (32) are symmetrically distributed; and / or The width of the U-shaped groove (311) is not less than the outer diameter of the composite material thin-walled tube (1).

3. The apparatus according to claim 1, characterized in that, The fastener (4) has a circular groove (41) with the same diameter as the first flange (21) and the second flange (22) of the flange assembly (2) in the middle. The circular groove (41) is used to accommodate the flange assembly (2); the depth of the groove is equal to the thickness of the flange assembly (2).

4. The apparatus according to claim 3, characterized in that, The positioning pins (42) are evenly distributed circumferentially inside the circular groove (41), and the number of them is the same as that of the positioning holes (312) and their positions correspond one-to-one.

5. The apparatus according to claim 1, characterized in that, The wall thickness of the composite material thin-walled tube (1) is 0.2~0.8mm.

6. The apparatus according to claim 1, characterized in that, The flange (11) includes a plurality of folded portions evenly distributed along the circumference; The through holes are provided on the folded portion and are evenly distributed along the circumference.

7. The apparatus according to claim 6, characterized in that, The number n of the folded portions and the radius R of the composite thin-walled tube (1) satisfy the following relationship: When R≤40mm, 1≤R / n≤1.5; When 40 < R ≤ 200 mm, 1.5 < R / n ≤ 2.5; When R > 200 mm, 2.5 < R / n ≤ 3.

8. A method for molding a composite material thin-walled pipe flange connection structure, characterized in that, The method is implemented using the apparatus according to any one of claims 1-7, and the method includes the following steps: The composite thin-walled tube (1) is subjected to flange (11) treatment and hole punching treatment to form flange (11) with through holes. The tube body of the composite thin-walled tube (1) is placed in the U-shaped groove (311) to position the composite thin-walled tube (1). Adhesive is applied to the surfaces of the flange (11), the first flange (21), and the second flange (22) of the composite thin-walled tube (1); Insert the locating pin (42) into the locating hole (312) to position the flange assembly (2) and improve the connection accuracy of the composite material thin-walled pipe flange connection structure.

9. The method according to claim 8, characterized in that, The flange (11) process includes dividing the opening of the composite thin-walled tube (1) into multiple parts, and then folding each part outward when the composite thin-walled tube is in a tough state to form a flange (11).

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