A method, application and computer program product for rapidly generating a two-dimensional geometric model mesh of a tire

Abstract

The present application relates to the technical field of tire design, and particularly relates to a method for quickly generating a tire two-dimensional geometric model grid, an application and a computer program product. The method for quickly generating a tire two-dimensional geometric model grid comprises the following steps: first, drawing auxiliary lines; second, exporting a file; third, reading a mesh.dxf file generated in the second step; fourth, performing geometric repair on lines in TireLines in the second step; fifth, generating a part closed area; sixth, generating a unit closed area; and seventh, identifying accurate unit information. The present application adds grid auxiliary lines to a tire two-dimensional geometric model, and then directly and accurately extracts grid data by using a program, so that not only the speed is fast (5 minutes are expected), but also the present application is free from dependence on third-party software, and the efficiency of dividing a grid of a tire geometric model is greatly improved, thereby providing technical support for tire numerical simulation.

Description

Technical Field

[0001] This invention relates to the field of tire design technology, and in particular to a method, application, and computer program product for rapidly generating two-dimensional geometric model meshes of tires. Background Technology

[0002] Tire numerical simulation is a key and hot topic in tire R&D technology. Through simulation, it is possible to predict almost all tire performance characteristics, such as deformation, stress, contact patch conditions, and rolling resistance, which has a significant guiding role in the evaluation and analysis of tire performance. The foundation of numerical simulation technology is the mesh generation of the geometric model. Due to the complex geometric features of tires, mesh generation is difficult to automate completely.

[0003] Chinese invention patent application (publication number: CN103246792A, publication date: 2013-08-14) discloses a preprocessing method for two-dimensional mesh generation of tire finite element method. The method involves manually generating the mesh by adding auxiliary lines, which allows for autonomous control of the mesh and generates as many quadrilateral meshes as possible. However, it requires manually picking the intersection point of each contour line and the auxiliary line and specifying the inner contour line. Furthermore, the generated mesh needs to be manually adjusted, which is very tedious and is expected to take one hour, thus wasting time.

[0004] Chinese invention patent application (publication number: CN108287975A, publication date: 2018-07-17) introduces a method for quickly realizing a two-dimensional mesh of tire finite element method. It requires generating inner and outer contour exchange files, tire carcass reinforcement material exchange files and other drawing exchange files, and relies on UG third-party software to generate the mesh, which is quite cumbersome.

[0005] Chinese invention patent application (publication number: CN114782585A, publication date: 2022-07-22) discloses a direct finite element mesh generation method based on tire structural features. The method generates meshes by directly discretizing the surface regions of the components. However, the tire geometry is complex and the component shapes are very irregular, making it difficult to generate high-quality quadrilateral-based meshes. Generating all triangular meshes would result in a significant loss of computational accuracy, and there is a high probability that some areas cannot be automatically meshed. Summary of the Invention

[0006] To address the aforementioned technical challenges—namely, the complex geometry of tires, which makes fully automated mesh generation difficult—currently reported techniques suffer from drawbacks such as slow speed, inability to automatically generate meshes in certain areas, cumbersome procedures, or reliance on third-party software. The purpose of this invention is to provide a method for rapidly generating meshes for two-dimensional tire geometric models. This method involves adding mesh auxiliary lines to the tire's two-dimensional geometric model and then directly and accurately extracting the mesh data using a program. This approach is not only fast but also eliminates reliance on third-party software, significantly improving the efficiency of mesh generation for tire geometric models and providing technical support for tire numerical simulation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for rapidly generating a 2D geometric model mesh of a tire, comprising the following steps:

[0009] The first step is to draw auxiliary lines.

[0010] Add auxiliary lines to the existing 2D geometric model of the tire. The auxiliary lines are all line segments or polylines. The auxiliary lines must pass through all intersection points of the components in the tire geometric model. The auxiliary lines form triangles or quadrilaterals with the lines in the raw material distribution map. The auxiliary lines are stored in a separate layer named WG. This layer only contains auxiliary lines.

[0011] The second step is to export the file.

[0012] Export the 2D tire model and auxiliary lines together as a DXF file and name it mesh.dxf;

[0013] The third step is to read the mesh.dxf file generated in the second step.

[0014] The ezdxf library in Python is used to read the mesh.dxf file, read the lines in the WG layer and store them in the GuideLines collection, and read the lines in other layers and store them in the TireLines collection;

[0015] The fourth step is to perform geometric repairs on the lines in TireLines from the second step.

[0016] In the TireLines set, distances less than d min Merge points or lines, d min The value ranges from 0.1mm to 0.5mm, and the TireLines set is updated after geometric repair.

[0017] Step 5: Generate the closed area of ​​the component.

[0018] The Python program is used to process the line data in TireLines, extract the smallest closed area, each closed area is a tire component, and the closed areas are stored in the collection ClosedAreas as the coordinates of points arranged in order;

[0019] Step 6: Generate the closed region of the unit.

[0020] Create a new element dictionary `ElementDict` to store information about the set of closed areas of elements; use a Python program to iterate through the closed areas C of each component in the `ClosedAreas` set. j Create a set Element and calculate C. j The smallest closed unit E formed by the intersection of all lines in the GuideLines set. i Its area is AE i Calculate E i With C j overlapping area CEA i Define the overlap coefficient c i =CEA i / AE i The set of units identified for each closed region is used as the value, and the closed region number is used as the key to add it to the dictionary ElementDict.

[0021] Step 7: Identify precise unit information

[0022] Excess points in the identified closed units are removed, i.e., points that are not located on the auxiliary lines; these points are considered invalid. After identifying the precise unit information, the Element set is updated, and ElementDict is updated.

[0023] As a preferred embodiment, in step three, line segments are stored with start and end coordinates, polylines are stored with coordinates of points arranged in sequence, and arcs are discretized into polylines with a maximum length of 0.1 mm and stored in the form of polylines.

[0024] As a preferred option, if c in step six i If the value is greater than 0.6, then the smallest closed unit E is considered to be... i Located in closed area C j Inside, add the coordinates of points Ei arranged in point order to the Element collection. If c i If the value is less than or equal to 0.6, then the smallest closed unit E is considered to be... i Located in closed area C j Do not add it to the Element collection.

[0025] Preferably, in step seven, a Python program is used to iterate through the enclosed region of each element in each element set generated in step six, and extract the coordinate point P in each enclosed region. k Find P k The minimum distance to all lines in the GuideLines set is denoted as l. k If l k If the value is greater than 0.01, the point is considered not to be on the auxiliary line. The coordinates of this point are removed from the geometric points of the enclosed region of the element set, while the order of other points remains unchanged. If l k If the value is less than or equal to 0.01, then the coordinates of the point are retained in the geometric points of the enclosed region of the element in the Element set.

[0026] Furthermore, the present invention also discloses the application of the method in tire simulation modeling.

[0027] Furthermore, the present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the method.

[0028] Furthermore, the present invention also discloses a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the method.

[0029] Furthermore, the present invention also discloses a computer program product, including a computer program or instructions that, when executed by a processor, implement the method.

[0030] This invention, by employing the aforementioned technical solution, adds mesh auxiliary lines to the two-dimensional geometric model of a tire, and then uses a program to directly and accurately extract mesh data. This not only results in high speed (estimated to be 5 minutes) but also eliminates the dependence on third-party software, greatly improving the efficiency of mesh generation for tire geometric models and providing technical support for tire numerical simulation. Attached Figure Description

[0031] Figure 1 This is the technology roadmap for this application;

[0032] Figure 2 Material distribution diagram for 21550R15 tires;

[0033] Figure 3 The unit diagram formed after adding auxiliary lines;

[0034] Figure 4 These are the guide lines contained in the WG layer;

[0035] Figure 5The GuideLines collection contains a portion of the data;

[0036] Figure 6 This is a partial data set for TireLines;

[0037] Figure 7 Data structures for line segments and polylines;

[0038] Figure 8 A schematic diagram of discretizing a circular arc into line segments;

[0039] Figure 9 It consists of dots and lines with minute distances between them;

[0040] Figure 10 This refers to the closed area of ​​the tire geometry model component.

[0041] Figure 11 This is a portion of the data in the ClosedAreas collection;

[0042] Figure 12 This is a partial data set for ElementDict;

[0043] Figure 13 This is a diagram of the closed regions of the generated cells;

[0044] Figure 14 A schematic diagram showing valid and invalid points within a closed region of a unit;

[0045] Figure 15 To remove invalid data from the closed region of the cell;

[0046] Figure 16 For accurately generated mesh diagrams. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented based on the technical solution of the present invention and provides detailed implementation methods, but the protection scope of the present invention is not limited to the following embodiments.

[0048] Taking 21550R15 tires as an example:

[0049] The first step is to draw auxiliary lines. This is done on an existing two-dimensional tire geometry model (such as...). Figure 2 Add auxiliary lines to the tire geometry model. These auxiliary lines are line segments or polylines and must pass through all intersections of components in the tire geometry model. The auxiliary lines should form triangular or quadrilateral units with the lines in the raw material distribution diagram (e.g., ...). Figure 3 The guide lines are stored in a separate layer named WG. This layer contains only the guide lines (e.g., ...). Figure 4 );

[0050] The second step is to export the file. Export the 2D tire model and auxiliary lines together as a DXF format file, and name it mesh.dxf;

[0051] The third step is to read the mesh.dxf file generated in the second step. This is done using the ezdxf library in a Python program, which reads the mesh.dxf file and stores the lines from the WG layer in the GuideLines collection (e.g., ...). Figure 5 ), read lines from other layers and store them in the TireLines collection (e.g. Figure 6 Line segments are stored using their starting and ending coordinates, while polylines are stored using the coordinates of points arranged in sequence (e.g., ...). Figure 7 The arc is discretized into a polyline with a maximum length of 0.1 mm (e.g., Figure 8 ), stored in polyline format;

[0052] The fourth step involves geometrically repairing the lines in the TireLines from the second step. This is because drawing errors or arc discrepancies can cause extremely small distances between lines or points that should intersect (e.g., ...). Figure 9 Therefore, the TireLines set needs to contain elements with a distance less than d. min Merge points or lines, d min The value ranges from 0.1mm to 0.5mm, and the TireLines set is updated after geometric repair.

[0053] Step 5: Generate closed regions for components. Use a Python program to process the line data in TireLines, extracting the smallest closed regions. Each closed region represents a tire component (e.g., ...). Figure 10 ), and store the closed region as the coordinates of points arranged in order in the collection ClosedAreas, such as Figure 11 .

[0054] Step 6: Generate the closed areas of the units. Create a new unit dictionary, ElementDict, to store information about the set of closed areas of the units. Use a Python program to iterate through the closed areas C of each component in the ClosedAreas set. j Create a set Element and calculate C. j The smallest closed unit E formed by the intersection of all lines in the GuideLines set. i Its area is AE i Calculate E i With C j overlapping area CEA i Define the overlap coefficient c i =CEA i / AE i If c iIf the value is greater than 0.6, then the smallest closed unit E is considered to be... i Located in closed area C j Inside, E i The coordinates of the points, arranged in point order, are added to the Element collection. If c i If the value is less than or equal to 0.6, then the smallest closed unit E is considered to be... i Located in closed area C j Within each enclosed region, the set of cells identified is used as the value, with the enclosed region's ID as the key, and added to the dictionary ElementDict, such as... Figure 12 As shown, the generated units are as follows Figure 13 As shown.

[0055] Step 7: Identify precise cell information. Since there may be redundant points within the identified closed cells—points not located on the auxiliary lines—these points are invalid and need to be discarded. For example... Figure 14 Using a Python program, iterate through the enclosed regions of each element in each element set generated in step six, and extract the coordinates P of each enclosed region. k Find P k The minimum distance to all lines in the GuideLines set is denoted as l. k If l k If the value is greater than 0.01, the point is considered not to be on the auxiliary line. The coordinates of this point are then removed from the geometric points of the enclosed region of the element set, while the order of other points remains unchanged (e.g., ...). Figure 15 If l k If the value is less than or equal to 0.01, the coordinates of that point are retained among the geometric points of the enclosed region of that cell in the Element set. After identifying the precise cell information, the Element set is updated, and then the ElementDict is updated.

[0056] At this point, the mesh diagram has been accurately generated, and the units have been grouped according to the components, such as... Figure 16 This facilitates further operations such as assigning material properties.

[0057] The steps described in this invention take approximately 5 minutes, while other patent reports estimate the time to be approximately 60 minutes. The method described in this patent is about 12 times more efficient, demonstrating the effectiveness of this invention patent.

[0058] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations 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. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for rapidly generating a two-dimensional geometric model mesh of a tire, characterized in that, The method includes the following steps: The first step is to draw auxiliary lines. Add auxiliary lines to the existing 2D geometric model of the tire. The auxiliary lines are all line segments or polylines. The auxiliary lines must pass through all intersection points of the components in the tire geometric model. The auxiliary lines form triangles or quadrilaterals with the lines in the raw material distribution map. The auxiliary lines are stored in a separate layer named WG. This layer only contains auxiliary lines. The second step is to export the file. Export the 2D tire model and auxiliary lines together as a DXF file and name it mesh.dxf; The third step is to read the mesh.dxf file generated in the second step. The ezdxf library in Python is used to read the mesh.dxf file, read the lines in the WG layer and store them in the GuideLines collection, and read the lines in other layers and store them in the TireLines collection; The fourth step is to perform geometric repairs on the lines in TireLines from the second step. In the TireLines set, distances less than d min Merge points or lines, d min The value ranges from 0.1mm to 0.5mm, and the TireLines set is updated after geometric repair. Step 5: Generate the closed area of ​​the component. The Python program is used to process the line data in TireLines, extract the smallest closed area, each closed area is a tire component, and the closed areas are stored in the collection ClosedAreas as the coordinates of points arranged in order; Step 6: Generate the closed region of the unit. Create a new element dictionary (ElementDict) to store information about the set of enclosed regions of elements; Using a Python program, iterate through the closed regions C of each component in the ClosedAreas collection. j Create a set Element and calculate C. j The smallest closed unit E formed by the intersection of all lines in the GuideLines set. i Its area is AE i Calculate E i With C j overlapping area CEA i Define the overlap coefficient c i =CEA i / AE i The set of units identified for each closed region is used as the value, and the closed region number is used as the key to add it to the dictionary ElementDict. Step 7: Identify precise unit information Excess points in the identified closed units are removed, i.e., points that are not located on the auxiliary lines; these points are considered invalid. After identifying the precise unit information, the Element set is updated, and ElementDict is updated.

2. The method for rapidly generating a two-dimensional geometric model mesh of a tire according to claim 1, characterized in that, In step three, line segments are stored with their starting and ending coordinates, polylines are stored with the coordinates of points arranged in order, and arcs are discretized into polylines with a maximum length of 0.1 mm and stored in polyline form.

3. The method for rapidly generating a two-dimensional geometric model mesh of a tire according to claim 1, characterized in that, In step six, if c i If the value is greater than 0.6, then the smallest closed unit E is considered to be... i Located in closed area C j Inside, add the coordinates of points Ei arranged in point order to the Element collection. If c i If the value is less than or equal to 0.6, then the smallest closed unit E is considered to be... i Located in closed area C j In addition, it is not added to the Element collection.

4. The method for rapidly generating a two-dimensional geometric model mesh of a tire according to claim 1, characterized in that, Step 7: Using a Python program, iterate through the enclosed region of each element in each element set generated in Step 6, and extract the coordinate point P of each enclosed region. k Find P k The minimum distance to all lines in the GuideLines set is denoted as l. k If l k If the value is greater than 0.01, the point is considered not to be on the auxiliary line. The coordinates of this point are removed from the geometric points of the enclosed region of the element set, while the order of other points remains unchanged. If l k If the value is less than or equal to 0.01, then the coordinates of the point are retained in the geometric points of the enclosed region of the element in the Element set.

5. The application of the method according to any one of claims 1-4 in tire simulation modeling.

6. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the method according to any one of claims 1-4.

7. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed by a processor, they implement the method described in any one of claims 1-4.

8. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, they implement the method described in any one of claims 1-4.

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