Automatic modeling method for three-dimensional composite pressure vessel

Abstract

This invention provides a method for automatically modeling a three-dimensional model of a composite pressure vessel. This method, which belongs to the technical field of composite pressure vessel design, utilizes Gmsh software to implement a complete automated process, from importing two-dimensional coordinate data, geometric transformation and three-dimensional body generation, physical grouping, meshing, and information output to model verification and correction. This method accurately and rapidly constructs a three-dimensional model of a composite pressure vessel and extracts key information, providing a reliable foundation for subsequent finite element analysis. Compared with existing technologies, this method offers advantages such as efficiency, accuracy, flexibility, and scalability, making it suitable for the design and analysis of composite pressure vessels in fields such as aerospace, energy, and chemical engineering.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material pressure vessel design, and specifically discloses an automatic modeling method for a three-dimensional model of a composite material pressure vessel. Background Art

[0002] With the rapid development of composite materials technology, composite pressure vessels have found widespread application in a variety of fields, including aerospace, automotive, and chemical engineering, due to their remarkable properties, such as lightweight, high strength, and corrosion resistance. However, the complex structural design and material properties of composite pressure vessels make accurately constructing 3D models and extracting relevant information during the design and simulation process a challenging task.

[0003] In existing technologies, manual modeling is often used to construct 3D models of composite pressure vessels. However, this approach is not only inefficient but also difficult to ensure model accuracy and integrity. This is especially true when dealing with complex structures and multiple material properties, making manual modeling methods inadequate and unable to meet the rapid design and analysis requirements of modern industry.

[0004] Furthermore, as the application of composite pressure vessels continues to expand, the demand for modeling and simulation analysis is also increasing. Traditional modeling methods can no longer meet the needs of the rapid development of modern industry. Therefore, there is an urgent need for an efficient, accurate, and flexible automatic modeling technology to support the research and development and production of composite pressure vessels. Summary of the Invention

[0005] In response to the problems of low efficiency and poor accuracy in manual modeling methods in the existing technology, the present invention proposes an automatic modeling method for three-dimensional models of composite pressure vessels based on programming Gmsh software. This method aims to achieve accurate description and modeling of complex structures of composite pressure vessels by integrating advanced algorithms and programming technologies, improve modeling efficiency and accuracy, and provide strong support for product optimization design.

[0006] The above-mentioned automatic modeling method of the three-dimensional model of the composite pressure vessel comprises the following steps:

[0007] S1, reading the two-dimensional coordinate point data of the composite pressure vessel 1 / 4 model, wherein the two-dimensional coordinate point data includes geometric information of all regions of the composite pressure vessel, importing the two-dimensional coordinate point data into the Gmsh software as initial data for modeling, and generating the two-dimensional 1 / 4 model of the composite pressure vessel;

[0008] S2, using Gmsh software to perform geometric transformation on the 2D 1 / 4 model to obtain a 3D 1 / 8 model;

[0009] S3, divide the elements and nodes of each region in the three-dimensional 1 / 8 model into corresponding physical groups, and the physical group label is i, i starts from 1 and the total number of regions in the composite pressure vessel, ndomain, is the total number of cycles;

[0010] S4, using the 3D 1 / 8 model obtained in step S2 as the 3D basic model, performing geometric transformation again using Gmsh software to obtain a 3D 2 / 8 model;

[0011] S5, divide the elements and nodes of each region in the three-dimensional 2 / 8 model into corresponding physical groups. The physical group label is i+ndomain, where i starts from 1 and the total number of regions in the composite pressure vessel, ndomain, is the total number of cycles.

[0012] S6, repeat step S4 until a complete three-dimensional overall model is obtained. After each step S4, the three-dimensional n / 8 model obtained in step S4 is grouped into physical groups according to step S5. n is 3, 4, 5, 6, 7, and 8, and six physical groups are obtained. The corresponding physical group labels are i+2. ndomain、i+3 ndomain、i+4 ndomain、i+5 ndomain、i+6 ndomain、i+7 ndomain;

[0013] S7, integrating the physical groups belonging to the same area in steps S3, S5 and S6 to obtain the physical group of the three-dimensional overall model, the corresponding physical group label is i+8 ndomain;

[0014] S8, according to the preset grid division parameters, the physical group i+8 Divide each area in ndomain into grids, extract and output the cell information and node information of each area, and save them;

[0015] S9, using finite element calculation software to read the unit and node information obtained in step S8, and to check and correct the three-dimensional overall model.

[0016] Steps S1-S9 are implemented by writing a script program using the API Fortran programming interface of the Gmsh software.

[0017] The regions in the composite pressure vessel include the liner, the plug and each ply. The geometric information of each region includes the coordinate point data, line segment data and the number of line segments in the region.

[0018] In step S1, the two-dimensional coordinate point data of the composite pressure vessel 1 / 4 model is stored in a TXT file.

[0019] In step S2, step S4 and step S6, the two-dimensional 1 / 4 model is rotated 90° using Gmsh software to obtain a three-dimensional 1 / 8 model, and then the three-dimensional 1 / 8 model is rotated, mirrored and translated to obtain a complete three-dimensional body model.

[0020] In step S8, the grid division parameters include grid size and grid shape; the unit information includes unit type, and the node information includes node coordinates; the saved file is in el3 format.

[0021] In step S9, the three-dimensional overall model is checked for geometric integrity, correctness of physical component grouping, and mesh quality.

[0022] Compared with the prior art, the present invention has the following beneficial effects.

[0023] 1. Efficiency: By programming the automated modeling process of Gmsh software, a complete three-dimensional model of the composite pressure vessel can be quickly generated and the required information can be extracted, greatly improving the modeling efficiency.

[0024] 2. Accuracy: Based on accurate coordinate data and precise control of programming operations, the accuracy and completeness of the model can be ensured, providing a reliable basis for subsequent analysis.

[0025] 3. Flexibility: Through programming, functions such as physical grouping and information output can be realized. Modeling parameters and output formats can be flexibly adjusted according to specific needs, improving the flexibility and accuracy of analysis.

[0026] 4. Scalability: This method is implemented based on the programming interface of the Gmsh software. Other functions can be expanded as needed, such as optimization algorithm integration, to further improve the efficiency and accuracy of modeling and analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 A flow chart of an automatic modeling method for a composite pressure vessel three-dimensional model;

[0029] Figure 2 This is a schematic diagram of the two-dimensional coordinate point data of the 1 / 4 model of the composite pressure vessel;

[0030] Figure 3 This is a schematic diagram of the position diagram of the three-dimensional 1 / 8 model;

[0031] Figure 4 This is a schematic diagram of the 3D overall model and mesh division in Gmsh software;

[0032] Figure 5 This is a schematic diagram of the lining physical group and mesh division in the Gmsh software;

[0033] Figure 6 This is a schematic diagram of the ply physical group and mesh division in the Gmsh software;

[0034] Figure 7 This is a schematic diagram of the plug physical group and mesh division in the Gmsh software;

[0035] Figure 8 This is a schematic diagram for reading the output nodes and finite element unit information of a single ply in the finite element calculation software;

[0036] Figure 9 Schematic diagram of reading the output nodes and finite element unit information of two layers in the finite element calculation software.

[0037] In the figure: 1- lining area; 2- laying area; 3- plugging area. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment provides a method for automatically modeling a three-dimensional model of a composite pressure vessel, which is implemented by writing a script program through the API Fortran programming interface of the Gmsh software. It can fully utilize computer technology and programming technology to achieve accurate description and modeling of the complex structure of the composite pressure vessel, improve modeling efficiency and accuracy, and meet the needs of modern industry for rapid design and analysis. Specifically, it includes the following steps.

[0041] S1, 2D coordinate data import:

[0042] The two-dimensional coordinate point data of the 1 / 4 model of the composite pressure vessel stored in the TXT file is read, and the two-dimensional coordinate point data includes the geometric information of all areas of the composite pressure vessel. The areas in the composite pressure vessel include the liner, the plug and each layer. The geometric information of each area includes the coordinate point data, the line segment data and the number of line segments in the area. The two-dimensional coordinate point data is imported into the Gmsh software as the initial data for modeling to generate a two-dimensional 1 / 4 model of the composite pressure vessel.

[0043] S2, geometric transformation and 3D body generation:

[0044] The two-dimensional 1 / 4 model was rotated 90° using Gmsh software to obtain a three-dimensional 1 / 8 model.

[0045] S3, physical grouping:

[0046] The units and nodes of the liner, plug and each ply in the three-dimensional 1 / 8 model are divided into corresponding physical groups. The physical group label is i, i starts from 1 and the total number of domains in the composite pressure vessel, ndomain, is the total number of cycles.

[0047] S4, geometric transformation and 3D body generation again:

[0048] The three-dimensional 1 / 8 model obtained in step S2 is used as the three-dimensional basic model, and the geometric transformation operation is performed again using the Gmsh software to obtain a three-dimensional 2 / 8 model.

[0049] S5, physical grouping again:

[0050] The elements and nodes of the liner, plug and each ply in the three-dimensional 2 / 8 model are divided into corresponding physical groups. The physical group label is i+ndomain, where i starts from 1 and the total number of domains in the composite pressure vessel, ndomain, is the total number of cycles.

[0051] S6, repeat step S4 until a complete three-dimensional overall model is obtained. After each step S4, the three-dimensional n / 8 model obtained in step S4 is grouped into physical groups according to step S5. n is 3, 4, 5, 6, 7, and 8, and six physical groups are obtained. The corresponding physical group labels are i+2. ndomain、i+3 ndomain、i+4 ndomain、i+5 ndomain、i+6 ndomain and i+7 ndomain.

[0052] During the geometric transformation process, the symmetry and integrity of the model must be ensured to ensure that the final generated three-dimensional overall model meets the design requirements.

[0053] Grouping physical groups helps to define independent material properties and set boundary conditions for different physical groups in subsequent finite element analysis.

[0054] S7, integrating the physical groups belonging to the same area in steps S3, S5 and S6 to obtain the physical group of the three-dimensional overall model, the corresponding physical group label is i+8 ndomain.

[0055] S8, grid division and information output:

[0056] Meshing is a key step in finite element analysis, which determines the accuracy and efficiency of the analysis. According to the preset meshing parameters (meshing parameters include mesh size and mesh shape, etc.), the physical group i+8 The lining, plugs and various plies in ndomain are meshed, and key data such as element type and node coordinates of the lining, plugs and various plies are extracted and output, and saved in el3 format for subsequent finite element calculation software to read and use.

[0057] S9, Model Checking and Correction:

[0058] Finite element calculation software is used to read the element and node information obtained in step S8 and inspect the overall 3D model. This inspection includes the geometric integrity, correctness of physical component grouping, and mesh quality of the overall 3D model. If any issues are found in the overall 3D model (such as geometric discontinuities, incorrect physical component grouping, or poor mesh quality), corrections and optimization are performed. These corrections and optimizations include re-meshing and adjusting physical component groupings. The corrected and optimized model is then inspected again to ensure that the accuracy and integrity of the overall 3D model meet design requirements.

[0059] Example 2

[0060] This example uses a single-ply composite pressure vessel as an example to illustrate 3D modeling and finite element mesh generation. The composite pressure vessel in this example consists of three regions: the port, the liner, and the single ply. This means the total number of regions, ndomain, in the composite pressure vessel is 3.

[0061] S1, obtain Figure 2The coordinate point data of the two-dimensional plane 1 / 4 composite pressure vessel shown is the initial data for modeling, which includes 65 coordinate points, 67 line segments and 3 areas. The three areas are lining area 1, laying area 2 and plugging area 3. Its two-dimensional plane data includes coordinate point data, line segment data, and the number of line segments in each area. For example, the closed loop area of ​​plugging area 3 consists of line segments numbered 1, 2, 3, 65, 66, and 67. Line segment 1 consists of coordinate points 1 and 2; line segment 2 consists of coordinate points 2 and 3; line segment 3 consists of coordinate points 3 and 4; line segment 65 consists of coordinate points 4 and 64; line segment 66 consists of coordinate points 64 and 65; and line segment 67 consists of coordinate points 65 and 1. Coordinate point 1 has the coordinates (100.0, 180.0); coordinate point 2 has the coordinates (130.0, 180.0); coordinate point 3 has the coordinates (136.65, 179.60); coordinate point 4 has the coordinates (140.0, 179.039); coordinate point 64 has the coordinates (14.0, 200.0); and coordinate point 65 has the coordinates (100.0, 200.0). Lining area 1, ply area 2, and plugging area 3 are similar. The two-dimensional coordinate point data is imported into the Gmsh software as the initial data for modeling to generate a two-dimensional 1 / 4 model of the composite pressure vessel.

[0062] S2, first rotate the 2D 1 / 4 model. Since Gmsh will overlap with the original figure after one rotation, rotate it 90° to get the following Figure 3 The three-dimensional 1 / 8 model shown.

[0063] S3, define the physical groups of the three-dimensional 1 / 8 model, and divide the units and nodes of the lining area 1, the ply area 2, and the plug area 3 in the three-dimensional 1 / 8 model into corresponding physical groups respectively. The physical group label is i, and i starts from 1 and the total number of cycles is 3. That is, the physical group labels corresponding to the lining area 1, the ply area 2, and the plug area 3 in the three-dimensional 1 / 8 model are 1, 2, and 3 respectively.

[0064] S4, using the three-dimensional 1 / 8 model obtained in step S2 as the three-dimensional basic model, performing composite operations such as rotation, mirroring, and translation on it using Gmsh software to obtain a three-dimensional 2 / 8 model.

[0065] S5, physical grouping again:

[0066] The physical groups of the three-dimensional 2 / 8 model are defined, and the elements and nodes of the lining area 1, the ply area 2, and the plug area 3 in the three-dimensional 2 / 8 model are divided into corresponding physical groups. The physical group label is i+ndomain, i starts from 1 and the total number of cycles is 3, that is, the physical group labels corresponding to the lining area 1, the ply area 2, and the plug area 3 in the three-dimensional 2 / 8 model are 4, 5, and 6 respectively.

[0067] S6. Repeat step S4 until a complete three-dimensional model is obtained. After each step S4, perform physical grouping according to step S5. In the three-dimensional 3 / 8 model, the physical group labels corresponding to liner area 1, ply area 2, and plug area 3 are 7, 8, and 9, respectively. In the three-dimensional 4 / 8 model, the physical group labels corresponding to liner area 1, ply area 2, and plug area 3 are 10, 11, and 12, respectively. In the three-dimensional 5 / 8 model, the physical group labels corresponding to liner area 1, ply area 2, and plug area 3 are 13, 14, and 15, respectively. In the three-dimensional 6 / 8 model, the physical group labels corresponding to liner area 1, ply area 2, and plug area 3 are 16, 17, and 18, respectively. In the three-dimensional 7 / 8 model, the physical group labels corresponding to liner area 1, ply area 2, and plug area 3 are 19, 20, and 21, respectively. In the three-dimensional 8 / 8 model, the physical group labels corresponding to liner area 1, ply area 2, and plug area 3 are 22, 23, and 24, respectively.

[0068] S7, integrating the physical groups belonging to the same area in steps S3, S5 and S6, and obtaining the physical group labels corresponding to the lining area 1, the ply area 2 and the plug area 3 in the three-dimensional overall model as 25, 26, and 27, respectively. Figure 4-Figure 7 For example, physical groups 1, 4, 7, 10, 13, 16, 19, and 22 all belong to the lining area 1. By integrating them, we can obtain the physical group 25 of the lining area 1 in the three-dimensional overall model. Figure 5 This grouping method helps to define independent material properties and set boundary conditions for different physical groups in subsequent finite element analysis.

[0069] S8. Mesh the lining area 1, ply area 2, and plug area 3 in the 3D overall model according to preset meshing parameters (such as mesh size and shape). A program can be written to set the maximum and minimum characteristic constants of the mesh to 50 and 10, respectively. 50 represents the upper limit, meaning the generated mesh characteristic length will not exceed this value; 10 is typically used to control the coarseness of the mesh; a smaller value results in a finer mesh. A program can be written to set the mesh smoothing times to 2000, which controls the mesh smoothing process. A larger value results in more smoothing times and a smoother mesh. These settings can be modified to meet the needs of subsequent 3D finite element analyses of varying precision.

[0070] After the meshing is completed, only the unit information and node information of physical groups 25, 26, and 27 are extracted and saved as a specific file el3 format, which can be read by finite element calculation software, such as Figure 8 shown.

[0071] S9, model checking and correction.

[0072] The aforementioned automatic modeling method also applies to composite pressure vessels with multi-layer layup structures. The total number of domains in a composite pressure vessel, ndomain, is the sum of the plugs, liner, and multiple layers. During the physical grouping and meshing steps, a separate physical group is assigned to each layer. Element data for each layer can also be output separately. Figure 9 Output node and finite element information for two-ply layup.

[0073] 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 method for automatically modeling a three-dimensional model of a composite pressure vessel, characterized in that: The steps include: S1, reading the two-dimensional coordinate point data of the composite pressure vessel 1 / 4 model, wherein the two-dimensional coordinate point data includes geometric information of all regions of the composite pressure vessel, importing the two-dimensional coordinate point data into the Gmsh software as initial data for modeling, and generating the two-dimensional 1 / 4 model of the composite pressure vessel; S2, using Gmsh software to perform geometric transformation on the 2D 1 / 4 model to obtain a 3D 1 / 8 model; S3, divide the elements and nodes of each region in the three-dimensional 1 / 8 model into corresponding physical groups, and the physical group label is i, i starts from 1 and the total number of regions in the composite pressure vessel, ndomain, is the total number of cycles; S4, using the 3D 1 / 8 model obtained in step S2 as the 3D basic model, performing geometric transformation again using Gmsh software to obtain a 3D 2 / 8 model; S5, divide the elements and nodes of each region in the three-dimensional 2 / 8 model into corresponding physical groups. The physical group label is i+ndomain, where i starts from 1 and the total number of regions in the composite pressure vessel, ndomain, is the total number of cycles. S6, repeat step S4 until a complete three-dimensional overall model is obtained. After each step S4, the three-dimensional n / 8 model obtained in step S4 is grouped into physical groups according to step S5. n is 3, 4, 5, 6, 7, and 8, and six physical groups are obtained. The corresponding physical group labels are i+2. ndomain、i+3 ndomain、i+4 ndomain、i+5 ndomain、i+6 ndomain、i+7 ndomain; S7, integrating the physical groups belonging to the same area in steps S3, S5 and S6 to obtain the physical group of the three-dimensional overall model, the corresponding physical group label is i+8 ndomain; S8, according to the preset grid division parameters, the physical group i+8 Divide each area in ndomain into grids, extract and output the cell information and node information of each area, and save them; S9, using finite element calculation software to read the unit and node information obtained in step S8, and to check and correct the three-dimensional overall model.

2. The automatic modeling method for a composite pressure vessel three-dimensional model according to claim 1, characterized in that: Steps S1-S9 are implemented by writing a script program using the API Fortran programming interface of the Gmsh software.

3. The automatic modeling method for a composite pressure vessel three-dimensional model according to claim 1, characterized in that: The regions in the composite pressure vessel include the liner, the plug and each ply. The geometric information of each region includes the coordinate point data, line segment data and the number of line segments in the region.

4. The automatic modeling method for a composite pressure vessel three-dimensional model according to claim 1, characterized in that: In step S1, the two-dimensional coordinate point data of the composite pressure vessel 1 / 4 model is stored in a TXT file.

5. The automatic modeling method for a composite pressure vessel three-dimensional model according to claim 1, characterized in that: In step S2, step S4 and step S6, the two-dimensional 1 / 4 model is rotated 90° using Gmsh software to obtain a three-dimensional 1 / 8 model, and then the three-dimensional 1 / 8 model is rotated, mirrored and translated to obtain a complete three-dimensional body model.

6. The automatic modeling method for a composite pressure vessel three-dimensional model according to claim 1, characterized in that: In step S8, the grid division parameters include grid size and grid shape; The unit information includes the unit type, and the node information includes the node coordinates; The saved file is in el3 format.

7. The automatic modeling method for a composite pressure vessel three-dimensional model according to claim 1, characterized in that: In step S9, the three-dimensional overall model is checked for geometric integrity, correctness of physical component grouping, and mesh quality.

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