Method for fast extraction of the outer profile of an asymmetric main groove tire

Abstract

The application relates to a kind of non-symmetrical major groove tire outer contour fast extraction methods, belong to the field of tire section contour design.Extract all node numbers on the section of three-dimensional finite element model arbitrary node of tire and the node corresponding body element number;Find the section outer contour edge from section body element set;Determine the starting point and end point of upper half outer contour, find two nodes adjacent to each boundary node based on section boundary set;According to the order of adjacent nodes, connect straight line between two points in turn, draw upper half outer contour line of tire section;Determine the end point of lower half outer contour, find two nodes adjacent to each boundary node based on section boundary set;According to the order of adjacent nodes, connect straight line between two points in turn, draw lower half outer contour line of tire section;Merge upper and lower half outer contour lines;Judge whether the tire section outer contour drawn meets the requirements, if the last node of outer contour is missing, it needs to be manually supplemented, and draw the complete outer contour line of tire section.

Description

Technical Field

[0001] This invention relates to the field of tire cross-sectional profile design, specifically to tire finite element model post-processing, and more specifically to a method for rapid extraction of the outer profile of an asymmetric tire with a main groove. Background Technology

[0002] As is well known, tire profile design is a crucial step in tire development. To date, various tire profile design theories have emerged, all of which require specifying key parameters such as section width, outer diameter, groove depth, and tread width. Most domestic tire structure engineers design tires based on experience, either by measuring competitor tire profiles or by combining classic profiles and changing parameters.

[0003] Before and after vulcanization, the various components of a tire undergo changes in position (thickness) across their cross-sections due to thermal flow. These changes significantly impact contact patch, wear, durability, handling, and the optimization of the tire profile. Therefore, it is essential to perform simulation analysis on a finite element model based on the designed cross-section to obtain the simulated inflated outer profile of the tire, thereby providing feedback guidance for tire cross-section design.

[0004] Alternatively, directly cutting and measuring the cross-section of the finished tire is too time-consuming, has large measurement errors, is labor-intensive, and makes it difficult to digitally reconstruct the tire cross-sectional profile, thus providing little feedback for design. Therefore, developing a method that can automatically, quickly, and accurately obtain the outer profile of the tire cross-section is of great significance in order to shorten the R&D cycle.

[0005] When drawing the outer contour of a tire section, the next node connected to the current node is usually determined based on the minimum distance between nodes. However, when encountering... Figure 4 In this case, the closest node to node 5 is node 8, not node 6, so directly connecting nodes 5 and 8 will result in an error.

[0006] Researchers have used a method of ray rotation scanning to extract points from the outer contour of a tire, specifically the method described in Chinese patent application number 202110614390.1, but encountered... Figure 5 In this case, the node closest to the ray is node 6, not node 5, and directly connecting nodes 4 and 6 will result in an error. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a method for rapid extraction of the outer contour of an asymmetric tire with a main groove. The method uses an algorithm to extract node information and element information on the cross-section where any node is located on the tire finite element model, and automatically draws the outer contour curve of the cross-section.

[0008] The technical solution adopted by this invention to solve its technical problem is: a method for rapid extraction of the outer contour of an asymmetric tire with a main groove, characterized in that the method includes the following steps:

[0009] (1) Extract all node numbers and corresponding volume element numbers on the cross section of any node in the three-dimensional finite element model of the tire, rotate the cross section around the Y-axis to the XOY plane, and then discard one layer of volume elements.

[0010] (2) Find the outer contour edge of the cross section from the cross section element set and save it to the cross section boundary set;

[0011] (3) Determine the starting and ending points of the upper outer contour, and find the two adjacent nodes of each boundary node based on the cross-sectional boundary set;

[0012] (4) Connect the two points in sequence according to the order of the adjacent nodes to draw the upper half of the outer contour line of the tire cross section;

[0013] (5) Determine the termination point of the lower half of the outer contour, and find the two adjacent nodes of each boundary node based on the cross-sectional boundary set;

[0014] (6) Connect the two points with straight lines in the order of adjacent nodes to draw the lower half of the outer contour line of the tire section;

[0015] (7) Merge the upper and lower outer contour lines;

[0016] (8) Determine whether the drawn tire cross-section outer contour meets the requirements. If the last node of the outer contour is missing, it needs to be added manually. At this point, the complete outer contour line of the tire cross-section is drawn.

[0017] In step (1) described above,

[0018] (1.1) Assume the coordinates of the center point O of the coordinate system of the three-dimensional finite element model of the tire are (0,0,0). Arbitrarily designate any node A on the tire finite element model as the reference point, and its coordinates are (...). Extract all node numbers that are on the same cross section as node A and save them to the cross section node set;

[0019] (1.2) Rotate the nodes of the cross-section node set around the Y-axis into the XOY plane;

[0020] (1.3) Traverse the cross-section node set, extract the two layers of volume element numbers to which the nodes on the cross-section belong, remove duplicate volume element numbers, discard one layer of volume element, and save it to the cross-section volume element set.

[0021] In step (1.1), the vector formed by the remaining nodes X(x,y,z) on the tire finite element model and point O is... sequentially with vector If the product is combined with the Y-axis, then... This indicates that node X and node A belong to the same cross section.

[0022] In step (1.2), assuming the node coordinates before rotation are (x, y, z), then the node coordinates after rotation are (x, y, z). ,y,0), that is, points within the XOY plane ( ,y).

[0023] In step (1.3), since the cross-section is located on the XOY plane, the Z values ​​of the nodes in the two layers of volume elements have opposite signs. By traversing the cross-section volume element set and deleting the volume elements containing nodes with Z values ​​greater than 0, the remaining layer of volume elements can be obtained.

[0024] In step (2), the first half of the nodes of the body element are the nodes of the cross-section surface element. By traversing the body element, the number of times each edge of the body element on the cross-section is shared can be found. Among them, the edge that is shared by the body element once is the boundary edge.

[0025] In step (3), the outer contour is drawn in half. Here, the outer contour of the part with a Y value greater than 0 is drawn first. First, the starting point and ending point of the upper outer contour are determined. The starting point is the point with the smallest Y value, which is the center line of the tread, and the ending point is the point with the smallest X value, which is the toe end. Except for these two points which have only one adjacent node, all other points have two adjacent nodes. Starting from the starting point, the points adjacent to each boundary node can be found by traversing the cross-sectional boundary set.

[0026] In step (4), starting from the starting point, it is determined whether the two adjacent nodes of the current node appear in the connected line. If the adjacent nodes that do not appear are selected to be connected, the connection to the end point of the upper half of the outer contour can be maintained in sequence.

[0027] In step (5), for the outer contour with a Y value less than 0, the starting point of the lower half contour and the starting point of the upper half contour are the same point. The point with the smallest X value, i.e. the toe end point, is taken as the termination point. The rest of the operation is the same as that of the upper half contour.

[0028] In step (7), if the toe endpoint is not located at the position with the minimum X value, the missing node needs to be added manually.

[0029] The beneficial effects of this invention are that it compensates for the misalignment of node connections when drawing the bottom of the tread groove. It uses an algorithm to extract node information and element information on the cross-section of any node on the tire finite element model, and uses the outer contour node information and peripheral element information to quickly draw the outer contour, which greatly reduces the error rate when connecting nodes at the bottom of the tread groove, thereby improving the accuracy of drawing the tire outer contour and the accuracy of tire performance simulation. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Figure 1 This is a flowchart of a method for rapid extraction of the outer contour of an asymmetric tire with a main groove according to the present invention;

[0032] Figure 2 This is a schematic diagram of a three-dimensional finite element model of a tire;

[0033] Figure 3 It is the volume element of the selected section;

[0034] Figure 4 This is a schematic diagram illustrating how the minimum distance method addresses problems encountered at the bottom of the tire tread grooves.

[0035] Figure 5 This is a schematic diagram illustrating how to handle problems encountered at the bottom of the tread groove using a method of ray rotation scanning of the outer contour to obtain points.

[0036] Figure 6 This is the final drawn outer contour curve of the tire. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be combined with the present invention. Figure 1 The technical solutions in the embodiments of this invention are clearly and completely described. Obviously, the three-dimensional finite element model of the tire used in this invention is only a part of the embodiments of this invention, not all of them. This invention is applicable to all rotating bodies after deformation under load. Of course, this invention is also applicable to obtaining the outer contour line directly from the two-dimensional cross-sectional finite element model of the tire. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] Combination Figure 1 The basic implementation steps of the method of the present invention are as follows:

[0039] (1) Extract all node numbers and corresponding volume element numbers on the cross section of any node in the three-dimensional finite element model of the tire, rotate the cross section around the Y-axis to the XOY plane, and then discard one layer of volume elements.

[0040] (2) Locate the outer contour edge of the cross section from the cross section element set;

[0041] (3) Determine the starting and ending points of the upper outer contour, and find the two adjacent nodes of each boundary node based on the cross-sectional boundary set;

[0042] (4) Connect the two points in sequence according to the order of the adjacent nodes to draw the upper half of the outer contour line of the tire cross section;

[0043] (5) Determine the termination point of the lower half of the outer contour, and find the two adjacent nodes of each boundary node based on the cross-sectional boundary set;

[0044] (6) Connect the two points with straight lines in the order of adjacent nodes to draw the lower half of the outer contour line of the tire section;

[0045] (7) Merge the upper and lower outer contour lines;

[0046] (8) Determine whether the drawn tire cross-section outer contour meets the requirements. If the last node of the outer contour is missing, it needs to be added manually. At this point, the complete outer contour line of the tire cross-section is drawn and saved as a CAD file.

[0047] The following examples provide a more detailed description of the present invention.

[0048] Assume the coordinate system of the tire finite element model is as follows Figure 2 As shown, the coordinates of the center point O are (0,0,0).

[0049] First, designate any node A on the tire finite element model as a reference point, whose coordinates are ( Extract the node numbers of all nodes on the same cross section as node A and save them to the cross section node set;

[0050] The vector formed by the remaining nodes X(x,y,z) on the tire finite element model and point O. sequentially with vector If the product is combined with the Y-axis, then... This indicates that node X and node A belong to the same cross section.

[0051] Next, the cross-section is rotated around the Y-axis onto the XOY plane. Assuming the node coordinates before rotation are (x, y, z), then the node coordinates after rotation are (x, y, z). The coordinates of a point in the XOY plane are ( ,y,0). ,y).

[0052] Secondly, traverse the cross-section node set, extract the two layers of volume element numbers to which the nodes belong on the cross-section, remove duplicate volume element numbers, discard one layer of volume elements, and save them to the cross-section volume element set, such as... Figure 3 As shown, the specific method is as follows:

[0053] Since the cross-section is located on the XOY plane, the Z values ​​of the nodes in the two layers of volume elements have opposite signs. By traversing the cross-section volume element set and deleting the volume elements containing nodes with Z values ​​greater than 0, the remaining layer of volume elements can be obtained.

[0054] Next, the outer contour edge of the cross-section is found from the cross-sectional element set and saved to the cross-sectional boundary set. The specific method is as follows:

[0055] The first half of the nodes of the volume element are the nodes of the cross-section element. By traversing the volume element, we can find the number of times each edge of the volume element on the cross-section is shared. Among them, the edge that is shared by the volume element once is the boundary edge.

[0056] Secondly, determine the starting and ending points of the upper outer contour, and find the two adjacent nodes of each boundary node based on the cross-sectional boundary set. The specific method is as follows:

[0057] The outer contour is drawn in half, starting with the portion where the Y-value is greater than 0. First, the starting and ending points of the upper outer contour are determined. The starting point is the node with the smallest Y-value, located at the center line of the tread, and the ending point is the node with the smallest X-value, located at the toe end. Except for these two points, which have only one adjacent node, all other points have two adjacent nodes. Starting from the starting point, traversing the boundary set of the cross-sections allows us to find the adjacent points of each boundary node.

[0058] Next, connect the two points with straight lines in the order of adjacent nodes to draw the upper half of the outer contour line of the tire cross-section. The specific method is as follows:

[0059] Starting from the starting point, determine whether the two adjacent nodes of the current node appear within the already connected lines. Select and connect the adjacent nodes that do not appear to maintain the connection to the end point of the upper outer contour.

[0060] Secondly, determine the termination point of the lower half of the outer contour. Based on the cross-sectional boundary set, find the two adjacent nodes of each boundary node. The specific method is as follows:

[0061] For the outer contour where the Y value is less than 0, the starting point of the lower half contour and the starting point of the upper half contour are the same point. The point with the smallest X value, i.e., the toe endpoint, is taken as the ending point. The already drawn upper half boundary set is removed from the cross-sectional boundary set to obtain the lower half boundary set. Starting from the starting point, traversing the lower half boundary set will find the points adjacent to each lower half boundary node.

[0062] Next, connect the two points with straight lines in the order of adjacent nodes to draw the lower half of the outer contour line of the tire section. The specific method is as follows:

[0063] Starting from the starting point, determine whether the two adjacent nodes of the current node appear within the already connected lines. Select and connect the adjacent nodes that do not appear to maintain the connection to the end point of the lower half of the outer contour.

[0064] Merge the upper and lower outer contour lines;

[0065] Finally, determine if the drawn tire cross-section outline meets the requirements. If the toe endpoint is not located at the position with the minimum X value, the missing node needs to be manually added. At this point, the complete outer outline of the tire cross-section is drawn and saved as a CAD file. Figure 6As shown.

[0066] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for rapid extraction of the outer contour of an asymmetric tire with main grooves, characterized in that, Includes the following steps: (1) Extract all node numbers and corresponding solid element numbers on the cross section where any node is located in the three-dimensional finite element model of the tire; The following method is used to extract node numbers and body element numbers: (1.1) Assume the coordinates of the center point O of the coordinate system of the three-dimensional finite element model of the tire are (0,0,0). Arbitrarily designate any node A on the tire finite element model as the reference point, and its coordinates are (...). Extract all node numbers that are on the same cross section as node A and save them to the cross section node set; (1.2) Rotate the nodes of the cross-section node set around the Y-axis into the XOY plane; (1.3) Traverse the cross-section node set, extract the two layers of volume element numbers to which the nodes on the cross-section belong, remove duplicate volume element numbers, discard one layer of volume elements, and save them to the cross-section volume element set. In step (1.3), since the cross section is on the XOY plane, the Z values ​​of the nodes contained in the two layers of volume elements have opposite signs. By traversing the cross section volume element set and deleting the volume elements containing nodes with Z values ​​greater than 0, the remaining layer of volume elements can be obtained. (2) Find the outer contour edge of the cross section from the cross section element set and save it to the cross section boundary set; (3) Determine the starting and ending points of the upper outer contour, and find the two adjacent nodes of each boundary node based on the cross-sectional boundary set; (4) Connect the two points in sequence according to the order of the adjacent nodes to draw the upper half of the outer contour line of the tire cross section; (5) Determine the termination point of the lower half of the outer contour, and find the two adjacent nodes of each boundary node based on the cross-sectional boundary set; (6) Connect the two points with straight lines in the order of adjacent nodes to draw the lower half of the outer contour line of the tire section; (7) Merge the upper and lower outer contour lines; (8) Determine whether the drawn tire cross-section outer contour meets the requirements. If the last node of the outer contour is missing, it needs to be added manually. At this point, the complete outer contour line of the tire cross-section is drawn.

2. The method for rapid extraction of the outer contour of an asymmetric tire with main grooves according to claim 1, characterized in that... In step (1.1), the vector formed by the remaining nodes X(x,y,z) on the tire finite element model and point O is... sequentially with vector If the product is combined with the Y-axis, then... This indicates that node X and node A belong to the same cross section.

3. The method for rapid extraction of the outer contour of an asymmetric tire with a main groove according to claim 1, characterized in that... In step (1.2), assuming the node coordinates before rotation are (x, y, z), then the node coordinates after rotation are (x, y, z). ,y,0), that is, points within the XOY plane ( ,y).

4. The method for rapid extraction of the outer contour of an asymmetric tire with a main groove according to claim 1, characterized in that... In step (2), the first half of the nodes of the body element are the nodes of the cross-sectional surface element. By traversing the body element, the number of times each edge of the body element on the cross-section is shared can be found. Among them, the outer contour edge is shared by the body element once.

5. The method for rapid extraction of the outer contour of an asymmetric tire with main grooves according to claim 1, characterized in that... In step (3), the outer contour is drawn in half. Here, the outer contour of the part with Y value greater than 0 is drawn first. First, the starting point and ending point of the upper half of the outer contour are determined. The starting point is the point with the smallest Y value, i.e. the center line of the tread, and the ending point is the point with the smallest X value, i.e. the toe end point. Except for these two points which have only one adjacent node, the other points have two adjacent nodes. Starting from the starting point, the points adjacent to each boundary node can be found by traversing the cross-sectional boundary set.

6. The method for rapid extraction of the outer contour of an asymmetric tire with main grooves according to claim 1, characterized in that... In step (4), starting from the starting point, it is determined whether the two adjacent nodes of the current node appear in the connected line. If the adjacent nodes that do not appear are selected to be connected, the connection to the end point of the upper half of the outer contour can be maintained in sequence.

7. The method for rapid extraction of the outer contour of an asymmetric tire with a main groove according to claim 1, characterized in that... In step (5), for the outer contour with a Y value less than 0, the starting point of the lower half contour and the starting point of the upper half contour are the same point. The point with the smallest X value, i.e. the toe end point, is taken as the termination point. The rest of the operation is the same as that of the upper half contour.

8. The method for rapid extraction of the outer contour of an asymmetric tire with a main groove according to claim 1, characterized in that... In step (7), if the toe endpoint is not located at the position with the minimum X value, the missing node needs to be added manually.

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