Composite metal lining cylindrical shell structure and forming process thereof

Abstract

The invention relates to the technical field of advanced composite material design and manufacturing, in particular to a composite metal lining cylindrical shell structure and a forming process thereof.The cylindrical shell structure comprises a metal lining, a functional coating and a carbon fiber composite material layer, and a three-dimensional mortise and tenon array structure is arranged on the surface of the metal lining; the functional coating is arranged between the metal lining and the carbon fiber composite material layer, and the carbon fiber composite material layer is connected with the metal lining through a compression molding process. According to the forming process, a tenon-and-mortise structure is utilized, a metal lining with a tenon is manufactured through mold pressing by means of interlocking between the tenon and a mortise, a functional layer can be additionally arranged on the metal lining, then carbon fiber cloth is laid on the metal lining according to the layer laying sequence, and finally the cylindrical shell structure is obtained in a mold pressing forming mode. The invention provides a new normal form for the design of the lightweight pressure vessel, is particularly suitable for extreme working condition demand scenes such as low-temperature storage tanks of aerospace shuttle devices and pressure-resistant cabins of deep sea detection equipment, and has remarkable technical and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of advanced composite material design and manufacturing, in particular to a composite metal lined cylindrical shell structure and a forming process thereof. Background Art

[0002] In modern industry, material properties play a key role in the overall effectiveness of equipment. Traditional metal shell material systems have many defects, which seriously restrict the performance improvement and application expansion of related equipment. Taking aviation aluminum alloy fuel storage tanks as an example, according to ASTM D7568 standard test data, the shell mass accounts for more than 40% of the total system mass, which significantly limits the payload and range parameters of the aircraft, making it difficult to meet the growing performance requirements of the aviation field. In deep-sea operating environments, according to NACE TM0177 standard test results, titanium alloy shells under 6000m water pressure conditions suffer stress corrosion cracking, resulting in a service life reduction of up to 30%, which greatly affects the reliability and service life of deep-sea equipment. After enduring 10^6 torsional cycle loads, the fatigue strength retention rate of SAE 4340 steel drive shaft housings according to ISO 1143 standard fatigue test data shows that it is only 60% of the initial value, showing obvious performance degradation in dynamic load-bearing.

[0003] At the same time, existing composite materials technology also faces a series of bottlenecks. According to the ASTM D3846 test standard, the interlaminar shear strength of epoxy / carbon fiber composites prepared by traditional layup processes is typically ≤50MPa, less than 10% of the intralaminar strength. This results in interface delamination becoming the primary failure mode, posing a serious threat to structural safety. From a manufacturing economics perspective, the purchase cost of a single automatic fiber placement device exceeds $2 million, and the energy consumption of the autoclave curing process accounts for 42.7% of the manufacturing cost (according to the NASACR-195478 technical and economic analysis report). This high cost limits the large-scale application of composite materials. In terms of metal-composite connections, according to ISO 4587 standard test data, the failure probability of adhesive joints under 70MPa internal pressure conditions is as high as 15%. Finite element analysis results show that the interface delamination stress concentration coefficient exceeds 3.5, and the problem of weak interface connection is prominent.

[0004] Therefore, there is an urgent need to develop a new material system or preparation process to overcome the above-mentioned defects of traditional metal shell materials and existing composite materials, and to improve the comprehensive performance and application value of the equipment. Summary of the Invention

[0005] The object of the present invention is to provide a composite metal lined cylindrical shell structure and a forming process thereof, which can solve the above technical problems.

[0006] The present invention provides a composite metal-lined cylindrical shell structure, comprising a metal liner, a functional coating and a carbon fiber composite material layer. The surface of the metal liner is provided with a three-dimensional mortise and tenon array structure, the functional coating is arranged between the metal liner and the carbon fiber composite material layer, and the carbon fiber composite material layer is connected to the metal liner through a compression molding process.

[0007] Preferably, the ratio λ of the tenon height to the base material thickness in the three-dimensional mortise and tenon array structure is 0.25-0.35. The three-dimensional mortise and tenon array structure is constructed on the surface of the metal lining through CNC precision machining to achieve the dual functions of mechanical interlocking and stress diffusion.

[0008] Preferably, the functional coating comprises a polyimide thermal insulation layer and / or a silicon carbide wave absorbing layer.

[0009] Preferably, the ply angles of the carbon fiber composite material layers are symmetrically distributed at [0° / ±45° / 90°]s.

[0010] Specifically, the ply sequence and composition:

[0011] 0° layer: The fibers are laid along the main load direction (reference axis), providing axial stiffness and strength;

[0012] ±45° layer: includes +45° and -45° layers, used to resist shear loads and improve damage resistance;

[0013] 90° layer: The fibers are perpendicular to the main direction, enhancing lateral stiffness and compressive resistance;

[0014] The order in the square brackets [0° / ±45° / 90°] means starting from the middle surface, lay four layers in order: 0°, +45°, -45°, and 90°;

[0015] Symmetry (s stands for symmetry)

[0016] The plies are arranged in a mirrored manner with the midplane as the axis of symmetry. For example, if the plies in the upper half are arranged in the order of 0°, +45°, -45°, 90°, the order in the lower half will be 90°, -45°, +45°, 0°.

[0017] The total number of floors is 8, and the structure is:

[0018] 0°, +45°, -45°, 90°, 90°, -45°, +45°, 0°.

[0019] Design Objective: Symmetrical layup eliminates in-plane coupling with bending-torsion, reducing cure distortion and thermal stresses. A mix of angles (0°, ±45°, and 90°) balances multi-directional load capacity and improves the overall mechanical properties of the laminate. The laminate is constructed with eight plies arranged symmetrically in a specified order, each with 0°, ±45°, and 90° angles, to optimize stiffness and stability.

[0020] The present invention also provides a forming process for the composite metal lined cylindrical shell structure, comprising the following steps:

[0021] Step 1: Making a metal round tube: Making a metal round tube by hot rolling;

[0022] Step 2: Processing the tenon: Using water jet cutting to produce the corresponding tenon on the surface of the metal tube obtained in step 1, forming a metal lining with a three-dimensional mortise and tenon array structure;

[0023] Step 3, adding functional coating: adding polyimide thermal insulation layer and silicon carbide absorbing layer functional coating on the surface of the metal lining;

[0024] Step 4: Lay the carbon fiber layer: Lay the carbon fiber cloth on the metal lining at a symmetrically distributed layer angle of [0° / ±45° / 90°]s;

[0025] Step 5: Compression molding: A composite metal-lined cylindrical shell structure is produced through a compression molding process.

[0026] Preferably, the thickness of the functional coating in step 3 is 0.2-0.5 mm. If there are two layers, the thickness of each layer is 0.2-0.5 mm.

[0027] Preferably, in step 4, carbon fiber cloth is used as prepreg.

[0028] Preferably, the carbon fiber prepreg is an epoxy resin-based carbon fiber prepreg, specifically using nano-modified epoxy resin (shear strength ≥85MPa, ASTM D1002 standard), the mortise and tenon structure increases the interface contact area by 40%-60%, and cooperates with the nano-modified epoxy resin to form a mechanical-chemical dual bonding system.

[0029] Preferably, the material of the metal lining is one of aviation aluminum alloy and titanium alloy.

[0030] Preferably, the molding process is suitable for manufacturing lightweight pressure vessels in aerospace fuel storage and transportation systems, deep-sea energy equipment pressure vessels, and marine engineering buoyancy unit application scenarios.

[0031] Beneficial effects:

[0032] This invention proposes a biomimetic structural metal-composite integrated molding process, innovatively integrating the mortise and tenon interlocking principles of ancient Chinese wooden architecture with modern composite materials technology. Compared to traditional winding processes, this invention achieves breakthroughs in the following technical indicators: 1. Improved interfacial bonding strength; 2. Multifunctional integration: The compression molding process allows for pre-coating of functional coatings at the metal-composite interface, saving energy compared to post-processing coating processes; 3. Optimized manufacturing costs: The investment in automatic wire laying equipment is eliminated, and hot pressing energy consumption is reduced compared to traditional processes, resulting in lower overall costs. This technical solution provides a new paradigm for lightweight pressure vessel design, particularly suitable for applications requiring extreme conditions, such as cryogenic storage tanks for aerospace shuttles and pressure chambers for deep-sea exploration equipment, with significant technical and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a schematic diagram of the three-dimensional structure of the composite metal lined cylindrical shell structure of the present invention;

[0035] Figure 2 Schematic diagram of the composite metal lined cylindrical shell structure of the present invention from a side perspective;

[0036] Figure 3 Schematic diagram of the structure of the metal round tube produced in step 1 of the forming process of the present invention;

[0037] Figure 4 Schematic diagram of the structure of the metal lining with a three-dimensional mortise and tenon array structure in step 2 of the forming process of the present invention.

[0038] Explanation of the reference numerals: 1-metal lining, 2-carbon fiber composite material layer, 3-tenon. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Example 1

[0043] A composite metal lined cylindrical shell structure, such as Figure 1-2 As shown, it comprises a metal liner 1, a functional coating, and a carbon fiber composite layer 2. The metal liner surface is provided with a three-dimensional mortise and tenon array structure. The functional coating is disposed between the metal liner 1 and the carbon fiber composite layer 2, which is connected to the metal liner 1 via a compression molding process. The three-dimensional mortise and tenon array structure has a tenon height to substrate thickness ratio, λ, of 0.25-0.35. The functional coating includes one or both of a polyimide insulation layer and a silicon carbide absorbing layer. The carbon fiber composite layer is laid up at angles symmetrically distributed at [0° / ±45° / 90°]s.

[0044] A forming process of the composite metal lined cylindrical shell structure comprises the following steps:

[0045] Step 1: Making a metal round tube: Making a metal round tube by hot rolling;

[0046] Step 2, processing the tenon: using water jet cutting to produce the corresponding tenon on the surface of the metal tube obtained in step 1, forming a metal lining with a three-dimensional mortise and tenon array structure, the material of the metal lining is one of aviation aluminum alloy and titanium alloy;

[0047] Step 3, adding functional coating: adding polyimide thermal insulation layer and silicon carbide absorbing layer functional coating on the surface of the metal lining, the thickness of the functional coating is 0.2-0.5mm;

[0048] Step 4: Laying carbon fiber plies: Lay carbon fiber cloth (prepreg) on the metal liner at a symmetrically distributed ply angle of [0° / ±45° / 90°]s; the carbon fiber prepreg is an epoxy resin-based carbon fiber prepreg, specifically using nano-modified epoxy resin (shear strength ≥85MPa, ASTM D1002 standard), and the mortise and tenon structure increases the interface contact area by 40%-60%, and forms a mechanical-chemical dual bonding system with the nano-modified epoxy resin;

[0049] Step 5: Compression molding: A composite metal-lined cylindrical shell structure is produced through a compression molding process.

[0050] The above-mentioned molding process is suitable for the manufacture of lightweight pressure vessels in aerospace fuel storage and transportation systems, deep-sea energy equipment pressure vessels, and marine engineering buoyancy unit application scenarios.

[0051] The structure of the present invention utilizes a new process, using a mortise and tenon structure, through the interlocking between the tenon and the mortise, and combined with high-strength glue (nano-modified epoxy resin). A metal lining with a tenon is produced by molding. A polyimide insulation layer and a silicon carbide absorbing layer can be added to the metal lining, and then carbon fiber cloth is laid on the metal lining in a layered order. Finally, a cylindrical shell structure is obtained by molding.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite metal lined cylindrical shell structure, characterized in that: It includes a metal lining, a functional coating and a carbon fiber composite material layer. The surface of the metal lining is provided with a three-dimensional mortise and tenon array structure. The functional coating is arranged between the metal lining and the carbon fiber composite material layer. The carbon fiber composite material layer is connected to the metal lining through a compression molding process.

2. The composite metal lined cylindrical shell structure according to claim 1, characterized in that: The ratio λ of the tenon height to the base material thickness in the three-dimensional mortise and tenon array structure is 0.25-0.

35.

3. The composite metal lined cylindrical shell structure according to claim 1, characterized in that: The functional coating comprises a polyimide heat insulation layer and / or a silicon carbide wave absorbing layer.

4. The composite metal lined cylindrical shell structure according to claim 1, characterized in that: The ply angles of the carbon fiber composite material layers are symmetrically distributed according to [0° / ±45° / 90°]s.

5. A forming process for a composite metal lined cylindrical shell structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Making a metal round tube: Making a metal round tube by hot rolling; Step 2: Processing the tenon: Using water jet cutting to produce the corresponding tenon on the surface of the metal tube obtained in step 1, forming a metal lining with a three-dimensional mortise and tenon array structure; Step 3, adding functional coating: adding polyimide thermal insulation layer and silicon carbide absorbing layer functional coating on the surface of the metal lining; Step 4: Lay the carbon fiber layer: Lay the carbon fiber cloth on the metal lining at a symmetrically distributed layer angle of [0° / ±45° / 90°]s; Step 5: Compression molding: A composite metal-lined cylindrical shell structure is produced through a compression molding process.

6. The forming process of the composite metal lined cylindrical shell structure according to claim 5, characterized in that: The thickness of the functional coating in step 3 is 0.2-0.5 mm.

7. The forming process of the composite metal lined cylindrical shell structure according to claim 5, characterized in that: In step 4, carbon fiber cloth is used as prepreg.

8. The forming process of the composite metal lined cylindrical shell structure according to claim 5, characterized in that: Carbon fiber prepreg is epoxy resin based carbon fiber prepreg.

9. The forming process of the composite metal lined cylindrical shell structure according to claim 5, characterized in that: The material of the metal lining is one of aviation aluminum alloy and titanium alloy.

10. The forming process of the composite metal lined cylindrical shell structure according to claim 5, characterized in that: The molding process is suitable for manufacturing lightweight pressure vessels in aerospace fuel storage and transportation systems, deep-sea energy equipment pressure vessels, and marine engineering buoyancy unit application scenarios.

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