A composite pressure pipe and a method of manufacturing the same

Abstract

The present application relates to a composite pressure pipe and a manufacturing method, and belongs to the field of composite pressure pipes, solving the problems that the carbon fiber composite pipe is difficult to achieve the use requirement of the pressure pipe in terms of compression strength and is difficult to demold during forming. A composite pressure pipe comprises: a metal alloy honeycomb pipe, which comprises an inner skin, a metal alloy honeycomb structure and an outer skin from inside to outside; an insulating fiber layer arranged on the outer surface of the outer skin; and a carbon fiber composite layer arranged on the outer surface of the insulating fiber layer. The composite pressure pipe and the manufacturing method thereof adopt a metal alloy honeycomb pipe as the inner liner of the carbon fiber composite material, the metal alloy honeycomb pipe has strong pressure bearing capacity and can reinforce the pressure bearing performance of the carbon fiber composite pipe. In the manufacturing method, a water-soluble material is arranged on the inner surface of the mold, and after curing, the mold is placed in water. After the water-soluble material between the mold and the composite pipe dissolves, the mold is easily demolded.

Description

Technical Field

[0001] This invention relates to the field of composite material pressure-bearing technology, and in particular to a composite material pressure-bearing pipe and its manufacturing method. Background Technology

[0002] Pressure-bearing pipes are pipes capable of withstanding internal or external pressure. For example, pressure-bearing pipes can be used to transport fluid media, including gases, liquefied gases, steam, or flammable, explosive, toxic, or corrosive liquids. They can also be used in long-distance pipelines and heat exchange applications. Furthermore, some specialized fields require pipes with excellent pressure-bearing properties.

[0003] Current pressure-bearing pipes are generally made of pure metal or pure composite materials. To meet their pressure-bearing requirements, pure metal pipes typically have thicker walls, increasing their weight. Meanwhile, pure composite material pipes are prone to cracking at the ends under pressure. Therefore, designing a lightweight pressure-bearing pipe with excellent tensile and pressure-bearing properties is of great significance, especially to meet the high mechanical performance requirements in specialized fields such as aerospace. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a composite material pressure-bearing pipe and its manufacturing method to solve at least one of the following technical problems: Existing carbon fiber composite materials have excellent tensile properties, but when bearing pressure, they mainly rely on the strength of the resin matrix, and the compressive strength is difficult to meet the requirements of the pressure-bearing pipe. Providing a composite material pressure-bearing pipe with light weight and excellent tensile and compressive properties is an urgent problem to be solved; and during the manufacturing process of carbon fiber composite pipes, there are problems such as difficulty in demolding due to resin curing and pressure factors during molding.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] First aspect: The present invention provides a composite material pressure pipe, comprising: an inner liner layer and a composite material layer;

[0007] The inner liner consists of a metal alloy honeycomb tube, and from the inside out, it includes an inner skin, a metal alloy honeycomb structure, and an outer skin.

[0008] The composite material layer includes an insulating fiber layer and a carbon fiber composite material layer; the insulating fiber layer is disposed on the outer surface of the outer skin; and

[0009] A carbon fiber composite layer is disposed on the outer surface of the insulating fiber layer.

[0010] Optionally, the metal alloy honeycomb tube is a metal alloy honeycomb tapered tube.

[0011] Optionally, the materials for the metal alloy honeycomb structure include at least one of aluminum alloy and magnesium alloy.

[0012] Optional materials for the metal alloy honeycomb structure include AlSi. 10 Mg alloy.

[0013] Optionally, the inner skin, metal alloy honeycomb structure, and outer skin can be integrally formed by 3D printing.

[0014] Optionally, the materials of the inner and outer skins include at least one of aluminum alloy and magnesium alloy, the insulating fiber layer includes glass fiber cloth, and the carbon fiber composite material layer includes multilayer carbon fiber cloth.

[0015] Secondly, this invention provides a method for manufacturing a composite material pressure-bearing pipe, comprising the following steps:

[0016] Step (1): Provide a metal alloy honeycomb tube, which includes an inner skin, a metal alloy honeycomb structure and an outer skin from the inside out;

[0017] Step (2): Wrap insulating fiber prepreg around the outer surface of the outer skin.

[0018] Step (3): A carbon fiber prepreg layer is set on the outer surface of the insulating fiber prepreg fabric. The carbon fiber prepreg layer is formed by winding multiple layers of carbon fiber prepreg to obtain the preformed structure of the composite material tube.

[0019] Step (4): The preformed structure is placed into a mold for curing to form a composite material tube. The inner surface of the mold is provided with a water-soluble material.

[0020] Step (5): After curing, the mold is placed in water. The water-soluble material between the mold and the composite material pipe dissolves and the mold is demolded to form a composite pressure pipe.

[0021] Optionally, the mold includes a conical cavity, with edge bosses of 2-5mm height provided at both ends of the inner curved surface of the conical cavity along the axial direction, water-soluble material provided on the inner curved surface of the conical cavity and located inside the edge bosses, and platforms provided on the upper and lower sides of the conical cavity respectively.

[0022] Optionally, a double-sided adhesive polytetrafluoroethylene film is disposed between the inner curved surface of the conical cavity and the water-soluble material.

[0023] Optionally, in step (4), the preformed structure is cured by compression molding.

[0024] Optionally, in step (2), the insulating fiber prepreg includes glass fiber plain weave prepreg, and the carbon fiber prepreg includes carbon fiber plain weave prepreg.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] 1. In the composite pressure-bearing pipe provided by the present invention, the metal alloy honeycomb pipe serves as the inner liner of the carbon fiber composite material. The metal alloy honeycomb pipe has strong pressure-bearing capacity and can enhance the pressure-bearing performance of the carbon fiber composite pipe. At the same time, compared with solid metal pipes, the honeycomb structure is conducive to reducing weight and achieving product lightweighting, which is of great significance for meeting the requirements of the aerospace industry for lightweighting and high performance.

[0027] 2. The metal alloy honeycomb tube and carbon fiber composite material in the composite pressure pipe provided by the present invention work synergistically to give the composite pressure pipe of the present invention advantages such as high strength, light weight, good heat resistance, and excellent tensile properties, while also having good pressure bearing performance, which can meet the requirements for use as a pressure pipe; for example, it can be used as a lightweight high-strength pipe with excellent tensile and pressure bearing properties for trusses in the aerospace field.

[0028] 3. In the manufacturing process of the composite material pressure pipe provided by the present invention, the axial pressure bearing capacity of the composite material pressure pipe can be further enhanced without significantly increasing the weight by wrapping carbon fiber prepreg on the outside.

[0029] 4. The composite material pressure pipe provided by the present invention has an insulating fiber layer between the metal alloy honeycomb pipe and the carbon fiber composite material, which can avoid galvanic corrosion caused by direct contact between the metal alloy and the carbon fiber, thereby improving the service life of the composite material pressure pipe.

[0030] 5. In the manufacturing method of the composite pressure pipe provided by the present invention, a water-soluble material is provided on the inner surface of the mold. After curing, the mold is placed in water. After the water-soluble material between the mold and the composite pipe dissolves, easy demolding can be achieved, which solves the problem of difficult demolding of carbon fiber composite pipes during the molding process due to resin curing and pressure factors in the prior art.

[0031] 6. The composite material pressure pipe provided by this invention has a boss on the edge of the inner surface of the mold. The water-soluble material is placed on the inner surface of the mold and located inside the edge boss, which is more conducive to demolding. Furthermore, a double-sided adhesive polytetrafluoroethylene film can be placed between the water-soluble material and the inner surface of the mold to further enhance the adhesion between the water-soluble material and the inner surface of the mold. Moreover, the polytetrafluoroethylene film is easy to remove after demolding, which facilitates the cleaning and maintenance of the mold.

[0032] 7. The inner skin, metal alloy honeycomb structure and outer skin of the metal alloy honeycomb tube of the present invention are integrally formed by 3D printing, which is simple to operate and has good bonding between the inner skin, metal alloy honeycomb structure and outer skin.

[0033] 8. The metal alloy honeycomb tube of the present invention is a tapered tube. On the one hand, it can increase the processability of 3D printing. Compared with a straight tube with uniform wall thickness, the cross section of the tapered tube is trapezoidal, which is beneficial to improve the structural stability between layers during the 3D printing process. On the other hand, the tapered tube structure is not prone to overall buckling during the pressure process and has a higher load-bearing capacity for angular impacts.

[0034] 9. The metal alloy honeycomb structure of the present invention is made of at least one of aluminum alloy and magnesium alloy, which is lightweight, thus making the composite material pressure pipe lighter.

[0035] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0036] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0037] Figure 1 This is a schematic diagram of the structure of a metal alloy honeycomb tube according to an embodiment of the present invention;

[0038] Figure 2 This is a schematic cross-sectional view of the composite material pressure-bearing pipe according to an embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram of the mold structure in the manufacturing method of the composite pressure pipe according to an embodiment of the present invention.

[0040] Symbol explanation:

[0041] 100-Composite material pressure pipe; 10-Metal alloy honeycomb pipe; 11-Inner skin; 12-Metal alloy honeycomb structure; 13-Outer skin; 20-Insulating fiber layer; 30-Carbon fiber composite material layer; 40-Edge boss; 50-Water-soluble material. Detailed Implementation

[0042] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0043] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0044] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0045] In this invention, unless otherwise specified, the numerical range "a~b" means including the endpoints a, b, and any numerical value between a and b.

[0046] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. Unless otherwise specified, the term "comprising" as used in the present invention can be open-ended or closed-ended. For example, "comprising" may mean that it may also include or contain other components not listed, or it may include only or contain the listed components.

[0047] Unless otherwise specified, the terms “length,” “thickness,” “upper,” “lower,” “vertical,” “inner,” “outer,” “axial,” etc., used in this invention to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0048] Please see Figure 1 and Figure 2 This invention provides a composite material pressure-bearing pipe 100, comprising: an inner liner layer and a composite material layer; the inner liner layer includes a metal alloy honeycomb tube 10, and the composite material layer includes an insulating fiber layer 20 and a carbon fiber composite material layer 30. The metal alloy honeycomb tube 10 includes, from the inside out, an inner skin 11, a metal alloy honeycomb structure 12, and an outer skin 13. The insulating fiber layer 20 is disposed on the outer surface of the outer skin 13, and the carbon fiber composite material layer 30 is disposed on the outer surface of the insulating fiber layer 20.

[0049] The inner skin 11, the metal alloy honeycomb structure 12, and the outer skin 13 are preferably, but not limited to, integrally formed by 3D printing, which is simple to operate and provides good bonding between the inner skin, the metal alloy honeycomb structure, and the outer skin. Furthermore, the honeycomb structure significantly reduces weight compared to ordinary solid tubes. For example, selective laser melting (SLM) technology is used for 3D printing, which is a relatively mature technology.

[0050] Preferably, the metal alloy honeycomb tube 10 is a metal alloy honeycomb conical tube. The metal alloy honeycomb conical tube is defined as the first part and the second part along the 3D printing layup direction, and the cross-sectional diameter of the first part is larger than that of the second part. On the one hand, the metal alloy honeycomb conical tube can increase the manufacturability of 3D printing. Compared with a straight tube with uniform wall thickness, the cross-section of the conical tube is trapezoidal, which is beneficial to increasing the structural stability between layers during the 3D printing process. On the other hand, the conical tube structure is not prone to overall buckling during pressure and has a higher load-bearing capacity for angular impacts.

[0051] The inner skin 11 and outer skin 13 can be selected from metal alloys or non-metallic fiber cloth. Preferably, the inner skin 11 and outer skin 13 include at least one of aluminum alloy and magnesium alloy. In this embodiment, the inner skin 11 and outer skin 13 are AlSi. 10 The Mg aluminum alloy, inner skin 11, outer skin 13 and metal alloy honeycomb structure 12 are integrally formed.

[0052] The material of the metal alloy honeycomb structure 12 is preferably, but not limited to, at least one of aluminum alloy and magnesium alloy. Aluminum alloy and magnesium alloy are lightweight, which in turn makes the composite pressure-bearing pipe 100 lighter. In this embodiment, the material of the metal alloy honeycomb structure 12 is AlSi. 10 Mg aluminum alloy.

[0053] An insulating fiber layer 20 is disposed between the metal alloy honeycomb tube 10 and the carbon fiber composite material layer 30 to prevent galvanic corrosion caused by direct contact between the metal alloy honeycomb tube 10 and the carbon fiber composite material layer 30, thereby extending the service life of the composite pressure-bearing tube 100. The insulating fiber layer 20 is preferably, but not limited to, wrapped around the outer surface of the outer skin 13. The insulating fiber layer 20 can be selected according to actual needs; preferably, the insulating fiber layer 20 includes, but is not limited to, fiberglass cloth. The number of fiberglass cloth layers can be selected according to actual needs.

[0054] The carbon fiber composite layer 30 comprises multiple layers of carbon fiber cloth. Preferably, the carbon fiber composite layer 30 is formed by winding multiple layers of carbon fiber cloth, and the number of layers of carbon fiber cloth can be selected according to the pressure requirements. Preferably, the carbon fiber composite layer 30 includes, but is not limited to, plain weave carbon fiber cloth.

[0055] In the composite material pressure-bearing pipe 100 provided by this invention, the metal alloy honeycomb tube 10 serves as the inner liner of the carbon fiber composite material tube. The metal alloy honeycomb tube 10 possesses strong pressure-bearing capacity, reinforcing the pressure-bearing performance of the carbon fiber composite material tube, thus resulting in better pressure-bearing capacity for the composite material pressure-bearing pipe 100. Simultaneously, the honeycomb structure, compared to a solid metal tube, helps reduce weight, achieving product lightweighting. The synergistic effect of the metal alloy honeycomb tube 10 and the carbon fiber composite material in the composite material pressure-bearing pipe 100 provides advantages such as high strength, light weight, good heat resistance, and excellent tensile strength, while also exhibiting good pressure-bearing performance, meeting the requirements for pressure-bearing pipe use. Furthermore, by setting a carbon fiber composite material layer 30 on the outside of the pressure-bearing pipe, the axial pressure-bearing capacity of the composite material pressure-bearing pipe 100 can be further enhanced without significantly increasing weight. By setting an insulating fiber layer 20 between the metal alloy honeycomb tube 10 and the carbon fiber composite material layer 30, galvanic corrosion caused by direct contact between the metal alloy and carbon fiber can be avoided, thereby improving the service life of the composite material pressure-bearing pipe 100. The inner skin 11, metal alloy honeycomb structure 12, and outer skin 13 of the metal alloy honeycomb tube 10 are integrally formed by 3D printing, which is simple to operate and also ensures good bonding between the inner skin 11, metal alloy honeycomb structure 12, and outer skin 13. The metal alloy honeycomb tube 10 is a metal alloy honeycomb tapered tube. On the one hand, the metal alloy honeycomb tapered tube can increase the manufacturability of 3D printing. Compared with a straight tube with uniform wall thickness, the cross-section of the tapered tube is trapezoidal, which is beneficial to increasing the structural stability between layers during 3D printing. On the other hand, the tapered tube structure is not prone to overall buckling during pressure and has a higher load-bearing capacity for angular impacts. The metal alloy honeycomb structure 12 is made of at least one of aluminum alloy and magnesium alloy, which is lightweight, making the composite pressure-bearing tube 100 lightweight and convenient to use.

[0056] This invention also provides a method for manufacturing the above-mentioned composite material pressure-bearing pipe 100, comprising the following steps:

[0057] Step (1): Provide a metal alloy honeycomb tube 10, which includes an inner skin 11, a metal alloy honeycomb structure 12 and an outer skin 13 from the inside to the outside.

[0058] Step (2): Wrap insulating fiber prepreg around the outer surface of the outer skin 13;

[0059] Step (3): A carbon fiber prepreg layer is set on the outer surface of the insulating fiber prepreg fabric. The carbon fiber prepreg layer is formed by winding multiple layers of carbon fiber prepreg to obtain the preformed structure of the composite material tube.

[0060] Step (4): The preformed structure is placed into a mold for curing to form a composite material tube. The inner surface of the mold is provided with a water-soluble material.

[0061] Step (5): After curing, the mold is placed in water. After the water-soluble material between the mold and the composite material pipe dissolves, the mold is demolded to form the composite pressure pipe 100.

[0062] In step (1), preferably, the inner skin 11, the metal alloy honeycomb structure 12, and the outer skin 13 are integrally formed by 3D printing to form the metal alloy honeycomb tube 10. This operation is simple, and the inner skin 11, the metal alloy honeycomb structure 12, and the outer skin 13 are well bonded. In this embodiment, laser selective melting (SLM) technology is used for the 3D printing of the metal alloy honeycomb tube 10.

[0063] In step (2), the type of insulating fiber prepreg is selected according to actual needs, as long as it can prevent galvanic corrosion of the metal alloy honeycomb tube 10 and the carbon fiber composite material layer 30. In this embodiment, the insulating fiber prepreg is a glass fiber plain weave prepreg.

[0064] The type of resin in the insulating fiber prepreg can be selected according to actual needs. Examples include, but are not limited to, epoxy resin, phenolic resin, polyimide resin, and bismaleimide resin. In this embodiment, the resin in the insulating fiber prepreg is epoxy resin.

[0065] In step (3), the carbon fiber prepreg layer is formed by winding multiple layers of carbon fiber prepreg. The type of carbon fiber prepreg can be selected according to actual needs. In this embodiment, the carbon fiber prepreg is a plain weave carbon fiber prepreg.

[0066] The type of resin in the carbon fiber prepreg can be selected according to actual needs. Examples include, but are not limited to, epoxy resin, phenolic resin, polyimide resin, and bismaleimide resin. In this embodiment, the resin in the carbon fiber prepreg is epoxy resin.

[0067] For step (4), please refer to [link / reference]. Figure 3 In some preferred embodiments, compression molding is employed. The mold includes a conical cavity, with edge bosses of 2-5 mm height at both ends of the inner curved surface of the conical cavity along the axial direction, and platforms on the upper and lower sides of the conical cavity to facilitate compression molding. Preferably, the conical cavity has a symmetrical structure. The water-soluble material is disposed on the inner curved surface of the conical cavity and located inside the edge bosses. The edge bosses facilitate the filling of the water-soluble material, thus facilitating subsequent demolding. The platforms on the upper and lower sides facilitate compression molding.

[0068] For example, compression molding is performed at room temperature. The preformed structure is placed in a mold and then pressed as a whole under a press. This allows for a tighter bond between the carbon fiber prepreg, the insulating fiber prepreg, and the inner liner, and improves the appearance quality of the pressure-bearing pipe. The calculation of the compression molding pressure depends on several factors, the most important of which are material properties, mold dimensions, and molding parameters. The calculation formula is as follows:

[0069] P = 2.5F / Dta

[0070] Where P represents the molding pressure, in MPa; F represents the clamping force of the mold, in N; Dt represents the outer diameter of the mold cavity, in m; and a represents the depth of the mold cavity, also in m.

[0071] In steps (4) and (5), water-soluble material refers to a material in which solid fillers are bonded together with water-soluble adhesives and made into a certain shape according to the usage requirements. It still has certain mechanical properties within the operating temperature range and can maintain its original shape. When demolding, solvents such as water are used to disperse it to obtain a product. As an example, it can be, but is not limited to, a mixture of polyvinyl alcohol and urea, or polyvinyl alcohol and clay.

[0072] The water-soluble material is preferably evenly spread on the inner curved surface of the conical cavity. The thickness of the water-soluble material is preferably flush with the edge protrusions at both ends. For example, multiple layers can be laid and compacted, and then the part that is higher than the mold edge can be scraped along the mold edge with a leveling ruler before being placed in a curing oven for curing.

[0073] More preferably, a double-sided adhesive polytetrafluoroethylene film is pasted on the inner surface of the mold to more firmly bond the water-soluble material to the outer metal mold. After molding, the water-soluble material can be dispersed with room temperature tap water to complete the demolding process. In the final stage of water dissolution, the single-sided adhesive polytetrafluoroethylene film on the inner surface of the mold can be directly removed to clean up any undissolved residue.

[0074] The purpose of the aforementioned water-soluble materials is mainly to achieve easy demolding. For example, paraffin wax is also a commonly used industrial demolding agent. Industrial paraffin wax can also be applied to the inner curved surface of the conical cavity. After cooling and solidification, it is processed to match the curvature of the inner curved surface. After molding, the entire mold is placed in a steam dewaxing kettle. After the wax melts, it can be easily demolded.

[0075] In the manufacturing method of the composite pressure-bearing pipe 100 provided by the present invention, a water-soluble material can be provided on the inner surface of the mold. After curing, the mold is placed in water. After the water-soluble material between the mold and the composite pipe dissolves, easy demolding can be achieved. Moreover, the composite pressure-bearing pipe will not be damaged during the demolding process, thus solving the problem of difficult demolding of carbon fiber composite pipes in the prior art. As an alternative, industrial paraffin wax can also be provided on the inner surface of the mold. After molding, the entire mold is placed in a steam dewaxing kettle. After the wax melts, it can be easily demolded.

[0076] The inner skin 11, the metal alloy honeycomb structure 12, and the outer skin 13 are integrally formed by 3D printing to form the metal alloy honeycomb tube 10. The operation is simple, and the inner skin 11, the metal alloy honeycomb structure 12, and the outer skin 13 are well integrated.

[0077] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and comparative examples.

[0078] Example 1:

[0079] In this embodiment, the composite material pressure pipe is a metal alloy honeycomb pipe with a taper of 3%. The diameter of the lower section of the aluminum alloy honeycomb pipe is slightly larger than that of the upper section. The outer skin, inner skin, and aluminum alloy honeycomb structure are made of AlSi10Mg aluminum alloy. The aluminum alloy honeycomb pipe is 3D printed in one piece using selective laser melting (SLM) technology.

[0080] The 3D printing process and parameters of aluminum alloy honeycomb cone tubes are as follows: The domestic BLT S300 laser selective melting manufacturing system is used. The printing process first establishes a three-dimensional model of the part, and then the contour model of each layer is obtained by slicing software. The powder spreading roller brings AlSi10Mg powder from the powder supply cavity into the forming cavity. The laser beam scans according to the model. After the scanning is completed, the forming cavity drops by one layer thickness and the powder is spread again. The laser scans again according to the next layer model, and finally the part is obtained by accumulation. The set SLM process parameters include: laser power 400W, scanning speed 400mm / s, layer thickness 30μm, and scanning spacing 60μm.

[0081] A layer of glass fiber plain weave prepreg is wound around the outer surface of the outer skin. A carbon fiber composite material layer is set outside the glass fiber plain weave prepreg. The carbon fiber composite material layer is made of four layers of carbon fiber plain weave prepreg, each layer of carbon fiber plain weave prepreg is 0.4 mm thick, forming a preformed structure of composite material tube.

[0082] The preformed structure is placed in a molding die for compression molding and curing. The molding die includes a symmetrical conical cavity with platforms on the upper and lower sides. The inner curved surface of the conical cavity has edge bosses with a height of 3mm at both ends along the axial direction. Double-sided adhesive polytetrafluoroethylene (PTFE) films are pre-attached to the inner curved surface of the die. A mixture of polyvinyl alcohol and clay is then used as a water-soluble material and placed on the inner curved surface of the conical cavity with the PTFE film attached, inside the edge bosses. Compression molding is performed at room temperature. After the preformed structure is placed in the die, the entire assembly is placed under a press for compression molding. After curing, the die is placed in a water tank to dissolve the water-soluble material between the die and the composite material tube. Demolding is then achieved, resulting in a composite pressure tube with a length of 100mm, an inner diameter of 50mm, an outer diameter of 59.2mm, and an angle of 0° between the tube axis and the carbon fiber direction.

[0083] Comparative Example 1:

[0084] Using existing carbon fiber composite pipes, the carbon fiber composite pipe in this comparative example has the same carbon fiber composite layer as that in Example 1, and the diameter of the carbon fiber composite pipe in this comparative example is the same as that of the composite pressure pipe in Example 1.

[0085] Axial crush tests were conducted on Example 1 and Comparative Example 1 using a CSS-88100 electronic universal testing machine. The loading rate was 3 mm / min, and the crush displacement was set to 45 mm. The test results are shown in Table 1 below.

[0086] Table 1 Comparison of Pressure Test Data

[0087]

[0088] As can be seen from Table 1, the initial peak load of Example 1 increased by 133% compared with Comparative Example 1, indicating that the load-bearing capacity of the embodiment disclosed in this invention is significantly better than that of pure carbon fiber composite tube.

[0089] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing a composite material pressure-bearing pipe, characterized in that, Includes the following steps: Step (1): Provide a metal alloy honeycomb tube, which includes an inner skin, a metal alloy honeycomb structure and an outer skin from the inside out; Step (2): Wrap insulating fiber prepreg around the outer surface of the outer skin. Step (3): A carbon fiber prepreg layer is provided on the outer surface of the insulating fiber prepreg fabric. The carbon fiber prepreg layer is formed by winding multiple layers of carbon fiber prepreg to obtain the preformed structure of the composite material tube. Step (4): The preformed structure is placed in a mold for curing to form a composite material tube. The preformed structure is cured by compression molding. Compression molding includes placing the preformed structure in the mold and then pressing it as a whole under a press. The mold includes a conical cavity, which is a symmetrical structure. The inner surface of the mold is provided with a water-soluble material. Step (5): After curing, the mold is placed in water. The water-soluble material between the mold and the composite material pipe dissolves and the mold is demolded to form the composite material pressure pipe.

2. The method for manufacturing a composite pressure-bearing pipe according to claim 1, characterized in that, The mold includes a conical cavity, with edge bosses provided at both ends of the inner curved surface of the conical cavity along the axial direction, a water-soluble material disposed on the inner curved surface of the conical cavity and located inside the edge bosses, and platforms provided on the upper and lower sides of the conical cavity respectively.

3. The method for manufacturing a composite pressure-bearing pipe according to claim 2, characterized in that, A double-sided adhesive polytetrafluoroethylene film is placed between the inner curved surface of the conical cavity and the water-soluble material.

4. The method for manufacturing a composite pressure-bearing pipe according to any one of claims 1-3, characterized in that, In step (2), the insulating fiber prepreg includes glass fiber plain weave prepreg, and the carbon fiber prepreg includes carbon fiber plain weave prepreg.

5. The method for manufacturing a composite pressure-bearing pipe according to claim 1, characterized in that, The metal alloy honeycomb tube is a metal alloy honeycomb cone tube.

6. The method for manufacturing a composite pressure-bearing pipe according to claim 1, characterized in that, The material of the metal alloy honeycomb structure includes at least one of aluminum alloy and magnesium alloy.

7. The method for manufacturing a composite pressure-bearing pipe according to claim 1, characterized in that, The material of the metal alloy honeycomb structure includes AlSi. 10 Mg aluminum alloy.

8. The method for manufacturing a composite pressure-bearing pipe according to claim 1, characterized in that, The inner skin, metal alloy honeycomb structure, and outer skin are integrally formed by 3D printing.

9. The method for manufacturing a composite pressure-bearing pipe according to claim 1, characterized in that, The materials of the inner and outer skins include at least one of aluminum alloy and magnesium alloy.

10. A composite material pressure-bearing pipe prepared by the manufacturing method of the composite material pressure-bearing pipe according to any one of claims 1 to 9, characterized in that, include: Inner liner and composite material layer; The inner liner layer includes a metal alloy honeycomb tube, and from the inside out, it includes an inner skin, a metal alloy honeycomb structure, and an outer skin. The composite material layer includes an insulating fiber layer and a carbon fiber composite material layer; An insulating fiber layer is disposed on the outer surface of the outer skin; And a carbon fiber composite material layer, disposed on the outer surface of the insulating fiber layer.

Images