Double-layer lattice sandwich structure pressure container and manufacturing method thereof

Abstract

The invention discloses a double-layer lattice sandwich structure pressure container and a manufacturing method thereof, and relates to the technical field of additive manufacturing, the double-layer lattice sandwich structure pressure container comprises an inner tank body, an outer tank body and a plurality of lattice structures, the inner tank body is located in the outer tank body, and the outer tank body is located in the outer tank body; a gap is formed between the inner tank body and the outer tank body, the lattice structures are all located between the inner tank body and the outer tank body, each lattice structure comprises a plurality of lattice supporting rods, the two ends of each lattice supporting rod are connected with the inner tank body and the outer tank body respectively, and the lattice supporting rods are connected with the outer tank body. The dot matrix supporting rod comprises an inner core and an outer shell, the inner core is located on the inner side of the outer shell, and the inner core and the outer shell are made of different materials. According to the pressure container with the double-layer dot matrix sandwich structure, the weight can be obviously reduced on the premise that the strength and rigidity required by a product are reserved, and the transportation cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and particularly to a double-layer lattice sandwich structure pressure vessel and a manufacturing method thereof. Background Art

[0002] With the development of industrial technology, pressure vessels have been applied in multiple fields such as energy, chemical industry, aerospace, etc. Factors such as their structural performance, load-bearing capacity, and manufacturing cost have gradually become research hotspots. Traditional pressure vessels are usually designed with a single-layer structure. Although they have certain strength and stability, there are still obvious deficiencies in terms of material utilization rate, lightweight, and performance adjustability. For pressure vessels with a double-layer structure, in order to ensure a certain strength, at both ends of the pressure vessel, the inner structure and the outer structure are connected together and are solid structures. The above-mentioned pressure vessels require more materials and have a larger mass during manufacturing, increasing the transportation cost. Summary of the Invention

[0003] The purpose of the present invention is to provide a double-layer lattice sandwich structure pressure vessel and a manufacturing method thereof, which can reduce the weight and transportation cost.

[0004] To achieve the above purpose, the present invention provides the following solutions:

[0005] The present invention provides a double-layer lattice sandwich structure pressure vessel, including: an internal tank body, an external tank body, and a plurality of lattice structures. The internal tank body is located inside the external tank body, and a plurality of the lattice structures are all located between the internal tank body and the external tank body. There is a gap between the internal tank body and the external tank body. The lattice structure includes a plurality of lattice struts. Two ends of the lattice strut are respectively connected to the internal tank body and the external tank body. The lattice strut includes an inner core and an outer shell. The inner core is located inside the outer shell, and the inner core and the outer shell are made of different materials.

[0006] In some specific solutions, the lattice structure includes at least three lattice struts. One end of the lattice strut is a connection end, and the other end of the lattice strut is a free end. The connection ends of the lattice struts are all connected to each other, and the free ends of the lattice struts do not contact each other.

[0007] In some specific solutions, the angles between adjacent lattice struts are the same; the lengths of the lattice struts of the lattice structure are all the same.

[0008] In some specific solutions, the connection end of the lattice strut is connected to the external tank body, and the free end of the lattice strut is connected to the internal tank body.

[0009] In some specific embodiments, a plurality of connection holes are provided on the outer tank, and the connection holes are used to connect with the lattice structure.

[0010] In some specific embodiments, the inner tank and the outer tank are coaxially arranged.

[0011] In some specific embodiments, the cross-section of the lattice strut is circular.

[0012] The present invention provides a manufacturing method for the double-layer lattice sandwich structure pressure vessel as described above, including:

[0013] Manufacturing the inner tank;

[0014] When manufacturing the lattice structure, it includes: planning the deposition path, dividing each lattice structure into several lattice structure layers from bottom to top, each lattice structure layer includes several lattice strut layers, each lattice strut layer includes a core layer and a shell layer located outside the core layer. When depositing each layer of the lattice structure layer, first deposit the shell layer of each lattice strut layer on the inner tank, and then deposit the core layer of each lattice strut layer, and complete the deposition of each lattice structure from bottom to top;

[0015] Manufacturing the outer tank outside several lattice structures;

[0016] Connecting the outer tank with the lattice structure.

[0017] In some specific embodiments, the shell layer is in a circular ring shape, and the core layer is circular.

[0018] In some specific embodiments, when manufacturing the inner tank, the lattice structure and the outer tank, an arc additive manufacturing technology is adopted, and the welding torch of the arc welding remains vertically downward.

[0019] The present invention has achieved the following technical effects compared with the prior art:

[0020] A gap is provided between the inner tank and the outer tank of the present invention, and a lattice structure is provided in the gap between the inner tank and the outer tank. By using the lattice structure as a compressive structure between the inner tank and the outer tank, the load-bearing capacity of the pressure vessel is improved, and due to the setting of the lattice structure, the overall weight can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1Schematic diagram of a pressure vessel with a double-layer lattice sandwich structure in some embodiments of the present invention Figure 1 (Partially removed);

[0023] Figure 2 Schematic diagram of a pressure vessel with a double-layer lattice sandwich structure in some embodiments of the present invention Figure 2 (Partially removed);

[0024] Figure 3 Schematic diagram of the internal tank and the lattice structure in some embodiments of the present invention (partially removed);

[0025] Figure 4 Schematic diagram of the external tank in some embodiments of the present invention Figure 1 (Partially removed);

[0026] Figure 5 Schematic diagram of the external tank in some embodiments of the present invention Figure 2 (Partially removed);

[0027] Figure 6 Schematic diagram of the lattice structure in some embodiments of the present invention;

[0028] Figure 7 Top view of the lattice structure in some embodiments of the present invention;

[0029] Figure 8 Partial schematic diagram of the connection between the lattice structure and the internal and external tanks respectively in some embodiments of the present invention;

[0030] Figure 9 Schematic diagram of the outer shell layer in some embodiments of the present invention;

[0031] Figure 10 Schematic diagram of the outer shell layer and the inner core layer in some embodiments of the present invention;

[0032] Figure 11 Schematic diagram of the lattice struts obtained by layer-by-layer deposition in some embodiments of the present invention;

[0033] Figure 12 Cross-sectional view of the lattice struts obtained by layer-by-layer deposition in some embodiments of the present invention;

[0034] Figure 13 Flow chart of the manufacturing process of the lattice structure in some embodiments of the present invention;

[0035] In the figure: 1 - internal tank, 2 - external tank, 3 - lattice structure, 4 - lattice struts, 5 - outer shell, 6 - inner core, 7 - connection holes, 8 - strengthening nodes, 9 - outer shell layer, 10 - inner core layer. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] The object of the present invention is to provide a double-layer lattice sandwich structure pressure vessel and its manufacturing method to reduce weight and transportation costs.

[0038] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0039] Embodiment 1

[0040] As Figures 1 to 12 shown, this embodiment provides a double-layer lattice sandwich structure pressure vessel, including: an inner tank 1, an outer tank 2, and a plurality of lattice structures 3. The inner tank 1 is located inside the outer tank 2, and there is a gap between the inner tank 1 and the outer tank 2. A plurality of lattice structures 3 are all located between the inner tank 1 and the outer tank 2. The lattice structure 3 includes a plurality of lattice struts 4. The two ends of the lattice strut 4 are respectively connected to the inner tank 1 and the outer tank 2. The lattice strut 4 includes an inner core 6 and an outer shell 5. The inner core 6 is located inside the outer shell 5, and the inner core 6 and the outer shell 5 are made of different materials. In this embodiment, the lattice structure 3 is used as the compressive structure between the inner tank 1 and the outer tank 2 of the double-layer pressure vessel, which can improve the bearing capacity and reduce the weight of the structure at the same time.

[0041] In the specific implementation of some embodiments, the inner tank 1 and the outer tank 2 are coaxially arranged.

[0042] In the specific implementation of some embodiments, the inner tank 1 and the outer tank 2 have the same shape. The inner tank 1 and the outer tank 2 both include a tank body and end structures located at both ends of the tank body. The tank body is a cylindrical hollow cylinder, and both end structures are hollow hemispherical. A plurality of lattice structures 3 are regularly arranged between the tank body of the inner tank 1 and the tank body of the outer tank 2. There is a gap between the end structure at one end of the inner tank 1 and the end structure at one end of the outer tank 2, and there is a gap between the end structure at the other end of the inner tank 1 and the end structure at the other end of the outer tank 2.

[0043] In the specific implementation of some embodiments, the gaps at corresponding positions between the inner tank 1 and the outer tank 2 are all the same.

[0044] In the specific implementation of some embodiments, the lattice structure 3 includes at least three lattice struts 4, preferably four lattice struts 4, forming a pyramid-shaped lattice structure 3. One end of each lattice strut 4 is a connection end, and the other end of each lattice strut 4 is a free end. The connection ends of all lattice struts 4 are connected to each other to form a strengthening node 8, and the free ends of all lattice struts 4 do not touch each other. The free ends of all lattice struts 4 are connected to the inner tank 1.

[0045] In the specific implementation of some embodiments, the angles between adjacent lattice struts 4 are the same.

[0046] In the specific implementation of some embodiments, the lengths of all lattice struts 4 of the lattice structure 3 are the same.

[0047] In the design of the lattice structure 3 in this embodiment, the inner core 6 and the outer shell 5 are differentially deposited with two metal materials according to the stress requirements of each region, so as to form a high-strength composite structure and further improve the overall mechanical properties. For example, the inner core 6 can be made of stainless steel material, and the outer shell 5 can be made of low-carbon steel material. The materials of the inner core 6 and the outer shell 5 can be selected differently according to requirements.

[0048] In the specific implementation of some embodiments, a number of connection holes 7 are provided on the outer tank 2. The connection holes 7 are used to connect with the connection ends of the lattice structure 3 by welding to form a high-strength and lightweight sandwich structure. Specifically, the connection ends of the lattice structure 3 extend out from the connection holes 7, and then the CMT welding process is used to fusion-weld the connection ends to the outer tank 2 to form a strengthening node 8, that is, a reliable mechanical interlock structure is formed. This connection method not only ensures the effective transmission of loads, but also maximally maintains the structural integrity of the outer tank 2, while achieving a lightweight design.

[0049] In the specific implementation of some embodiments, the cross-section of the lattice strut 4 is circular, and the cross-section is a cross-section perpendicular to the length direction of the lattice strut 4. For the lattice structure 3, two metal materials can be used. One metal material is the outer shell 5, and the other metal material is the inner core 6. During manufacturing, the CMT mode is used to form a circular sleeve-shaped outer layer, and then another metal wire is switched to fill the inner core 6 inside, and this process is repeated until the complete build height is deposited. The entire additive process uses an infrared thermal imager to monitor the interlayer temperature in real time and control the interlayer temperature to suppress welding deformation.

[0050] This embodiment designs the inner tank 1, the outer tank 2 and a number of lattice structures 3, and the lattice struts 4 of the lattice structure 3 are made of the inner core 6 and the outer shell 5 with different materials, which can save materials and improve the comprehensive performance and manufacturing efficiency of the pressure vessel.

[0051] The double-layer lattice sandwich structure pressure vessel proposed in this embodiment can significantly reduce the weight while retaining the required strength and stiffness of the product, reducing the transportation cost. At the same time, the lattice structure 3 has a certain buffering capacity as a whole. When cracks appear, the inner core 6 can prevent their continuous diffusion in time, significantly improving the impact resistance of the product. In addition, using different materials for the lattice struts 4 helps to achieve functional complementarity among the materials, realizing the collaborative optimization of the overall structure and improving the structural reliability and product safety.

[0052] Embodiment 2

[0053] As Figures 1 to 12 shown, this embodiment provides a manufacturing method for the double-layer lattice sandwich structure pressure vessel of Embodiment 1, including:

[0054] Manufacture the internal tank 1; when manufacturing the internal tank 1, use 316L stainless steel welding wire as the main material and carry out multi-layer and multi-pass surfacing to form the internal tank 1;

[0055] As Figure 13 shown, when manufacturing the lattice structure 3, it includes: the planning and design of the numerical control machining path, the deposition of the outer shell layer 9, the deposition of the inner core layer 10, repeating the deposition of the outer shell layer 9 and the inner core layer 10 until the complete lattice structure 3 is completed, and milling the lattice structure until the required size and accuracy are obtained; before depositing the lattice structure 3 outside the internal tank 1, manufacture a lattice structure sample for testing, conduct mechanical property tests on the lattice structure sample, and systematically evaluate the bearing capacity and reliability of the lattice structure 3 under complex working conditions. When the bearing capacity and reliability of the lattice structure 3 meet the requirements, deposit the lattice structure 3 outside the internal tank 1 as follows: use three-dimensional modeling software and path planning tools to generate the deposition path of the lattice structure 3 according to the structural design requirements of the pressure vessel, and combine the stress distribution of the structure to divide the material area, complete the design of the dual-material deposition area, divide each lattice structure 3 into several lattice structure layers from bottom to top, each lattice structure layer includes several lattice strut layers, and each lattice strut layer includes an inner core layer 10 and an outer shell layer 9 located outside the inner core layer 10. When depositing each layer of the lattice structure layer, first deposit the circular outer shell layer 9 of each lattice strut layer on the internal tank 1 to ensure that the pressure vessel has good geometric accuracy and external stiffness, and then deposit the circular inner core layer 10 of each lattice strut layer inside the outer shell layer 9. Through the way of layer-by-layer construction and the alternating deposition of the outer shell layer 9 and the inner core layer 10, the deposit reaches the required height to complete the deposition of each lattice structure 3; after the deposition of the lattice structure 3 is completed, use a numerical control machine tool to perform subtractive finishing on the lattice structure 3 to remove redundant surface materials to obtain the required shape, size and surface accuracy;

[0056] Manufacture an outer tank 2 outside a plurality of lattice structures 3; when manufacturing the outer tank 2, use 316L stainless steel welding wire as the main material and perform multi-layer multi-pass surfacing to form the outer tank 2;

[0057] Connect the outer tank 2 and the lattice structure 3.

[0058] In the specific implementation manners of some embodiments, the outer shell layer 9 is in an annular shape, the inner core layer 10 is in a circular shape, and in a layer-by-layer deposition manner, a zigzag interlocking structure is formed between the outer shell layer 9 and the inner core layer 10, as Figure 12 shown.

[0059] In the specific implementation manners of some embodiments, when manufacturing the inner tank 1, the lattice structure 3 and the outer tank 2, an arc additive manufacturing technology is adopted, preferably a cold metal transfer (CMT) welding process. During the deposition process, a positioner is used to change the angle and position of the deposited structure so that the welding torch of the arc welding remains vertically downward.

[0060] The manufacturing method of the double-layer lattice sandwich structure pressure vessel in this embodiment has achieved significant innovations in terms of structural design, material utilization rate, and manufacturing process compared with the manufacturing process of traditional pressure vessels, and has broad industrial application prospects. First, the double-layer lattice strut 4 design is introduced in this embodiment to achieve the coordinated cooperation between structures, effectively disperse the load, improve the specific strength and energy absorption capacity, and significantly enhance the overall structural performance. Secondly, by reasonably configuring two metal materials according to the stress distribution in different regions, the dual-material functional complementarity is realized, and the performance of the lattice structure 3 in terms of strength is significantly improved. In addition, in the manufacturing process, the high deposition efficiency of arc additive manufacturing is organically combined with the high dimensional accuracy of subtractive machining, which not only effectively overcomes the dimensional errors and surface quality problems existing in traditional additive manufacturing, but also significantly improves the manufacturing efficiency and finished product quality while ensuring the performance of the components. Finally, the manufacturing method of the double-layer lattice sandwich structure pressure vessel in this embodiment has good scalability and adaptability, is suitable for manufacturing metal structures with complex shapes and large sizes, and is particularly suitable for application in high-end equipment fields such as aerospace and ships where extremely high requirements are placed on structural performance and manufacturing accuracy.

[0061] In the production process of the manufacturing method of the double-layer lattice sandwich structure pressure vessel in this embodiment, through the cold metal transfer welding technology, the outer shell layer 9 surrounds the inner core layer 10 to complete the welding work of the dual materials, making the product have higher compressive strength and impact resistance than the single-metal structure. The deposition method from the inside out in this embodiment, first depositing the inner tank 1, then depositing the lattice structure 3, and finally depositing the outer tank 2, combined with the application of dual materials, expands the design freedom and performance customization space.

[0062] The manufacturing method of the double-layer lattice sandwich structure pressure vessel in this embodiment has the advantages of high efficiency, wide applicability, and high reliability, realizing the efficient construction of complex lattice sandwich structure pressure vessels and meeting the comprehensive performance requirements of high strength, light weight, and high precision.

[0063] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, 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 thus cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0064] In the description of the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] If the present invention discloses or involves components or structural members that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (such as using bolts or screws), or it can also be understood as: an inseparable fixed connection (such as riveting, welding). Of course, the mutually fixed connection can also be replaced by an integral structure (such as manufactured by an integral casting process) (except when it is obviously impossible to adopt the integral forming process).

[0066] In addition, the terms used to represent positional relationships or shapes in any technical solution disclosed in the present invention, unless otherwise stated, include states or shapes that are approximate, similar, or close to them.

[0067] Any component provided by the present invention can either be assembled from multiple separate components or be a single component manufactured by an integral forming process.

[0068] It should be noted that the structures, proportions, sizes, etc. depicted in the accompanying drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the conditions for the implementation of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0069] It should also be noted that in the embodiments of this application, the same reference numeral is used to represent the same component or the same part.

[0070] Adaptability changes made according to actual needs are all within the protection scope of the present invention.

[0071] Specific examples are used in the present invention to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A double-layer lattice sandwich structure pressure vessel, characterized in that: Comprising: An inner tank body (1), an outer tank body (2), and a plurality of lattice structures (3). The inner tank body (1) is located inside the outer tank body (2). A gap is provided between the inner tank body (1) and the outer tank body (2). A plurality of the lattice structures (3) are all located between the inner tank body (1) and the outer tank body (2). The lattice structure (3) includes a plurality of lattice struts (4). Two ends of the lattice strut (4) are respectively connected to the inner tank body (1) and the outer tank body (2). The lattice strut (4) includes a core (6) and a shell (5). The core (6) is located inside the shell (5). The core (6) and the shell (5) are made of different materials.

2. The double-layer lattice sandwich structure pressure vessel according to claim 1, wherein: The lattice structure (3) includes at least three lattice struts (4). One end of the lattice strut (4) is a connection end, and the other end of the lattice strut (4) is a free end. The connection ends of the lattice struts (4) are all connected to each other, and the free ends of the lattice struts (4) do not contact each other.

3. The double-layer lattice sandwich structure pressure vessel according to claim 2, characterized in that: The angles between adjacent lattice struts (4) are the same; the lengths of the lattice struts (4) of the lattice structure (3) are all the same.

4. The double-layer lattice sandwich structure pressure vessel according to claim 2, wherein: The connection end of the lattice strut (4) is connected to the outer tank body (2), and the free end of the lattice strut (4) is connected to the inner tank body (1).

5. The double-layer lattice sandwich structure pressure vessel according to claim 1, characterized in that: A plurality of connection holes (7) are provided on the outer tank body (2). The connection holes (7) are used for connecting with the lattice structure (3).

6. The pressure vessel with a double-layer lattice sandwich structure according to claim 1, characterized in that: The inner tank body (1) and the outer tank body (2) are coaxially arranged.

7. The double-layer lattice sandwich structure pressure vessel according to claim 1, wherein: The cross-section of the lattice strut (4) is circular.

8. A manufacturing method of a double-layer lattice sandwich structure pressure vessel as described in any one of claims 1-7, characterized in that: Comprising: Manufacturing the inner tank body (1); When manufacturing the lattice structure (3), it includes: planning a deposition path, dividing each lattice structure (3) into a plurality of lattice structure layers from bottom to top. Each lattice structure layer includes a plurality of lattice strut layers. Each lattice strut layer includes a core layer (10) and a shell layer (9) located outside the core layer (10). When depositing each lattice structure layer, first deposit the shell layer (9) of each lattice strut layer on the inner tank body (1), and then deposit the core layer (10) of each lattice strut layer, and complete the deposition of each lattice structure (3) from bottom to top. Manufacturing the outer tank body (2) outside a plurality of lattice structures (3); Connecting the outer tank body (2) and the lattice structure (3).

9. The manufacturing method of the double-layer lattice sandwich structure pressure vessel according to claim 8, characterized in that: The shell layer (9) is in a circular ring shape, and the core layer (10) is circular.

10. The manufacturing method of the double-layer lattice sandwich structure pressure vessel according to claim 8, characterized in that: When manufacturing the inner tank body (1), the lattice structure (3), and the outer tank body (2), an arc additive manufacturing technology is adopted, and the welding torch of the arc welding remains vertically downward.

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