JP6626707B2 - Method, apparatus and program for correcting tire FEM model - Google Patents

Description

  The present disclosure relates to a method, an apparatus, and a program for modifying a tire FEM model used for analyzing a pneumatic tire by a Finite Element Method (FEM).

  The tire FEM model data is a mesh model in which a pneumatic tire to be analyzed is divided into a plurality of elements, a group is set for the element, and a property including the physical property of the member is set for the group. I have. One member is composed of one or a plurality of groups.

  As a main component of a tire, there is a member in which fibers are topped with rubber, such as a belt, a carcass ply, and a chaher. Such a fiber member can be defined as a membrane element as shown in Patent Document 2. However, since the membrane element is an element having no thickness and a force acting only in the plane direction, it cannot be said that the analysis accuracy is good.

  In order to improve the analysis accuracy, recently, as shown in Patent Literature 3, a fiber member is defined as a solid element having anisotropy.

JP 2012-56392 A JP 2003-94916 A JP 2013-23146 A

  As a first problem, when defining a solid element having anisotropy, an anisotropic property having different physical properties depending on the direction is set as a property to be set for a group. Since different physical property values are defined according to the directions, it is important that the surface directions (element connectivity) of all the elements of the fiber member are uniform. The direction of the plane between the nodes is set according to the order of defining the nodes. Patent Literature 1 does not mention the connectivity of the elements of the fiber member when creating a tire model, but seems to describe unifying the order of defining the nodes.

  Automatic element generation logic is desired to ensure the connectivity of elements, but it is difficult to provide automatic element generation logic corresponding to all tire models because the shapes and arrangement positions of the members of the tire model are variously different. .

  Further, even once the tire model is created, the user may manually change the tire model. In this case, it is necessary to change the definition order of the nodes in the same order as the other elements in the fiber member, but the user may mistakenly set the definition. In this case, the orientation of the surface between the nodes is not unified, and unintended physical characteristics are set for the anisotropic property, and as a result, the analysis accuracy is reduced.

  As a second problem, in addition to the anisotropic element group constituting the fiber member, the uniformity of the surface between the nodes is required as a tire inner surface to which an internal pressure is applied, a ground contact candidate surface, or a contact surface with a rim. Are formed.

  The present disclosure has been made by focusing on at least one of the first problem and the second problem, and its purpose is to ensure the connectivity of the anisotropic element group or the surface between nodes. It is an object of the present invention to provide a method, an apparatus and a program for correcting tire FEM model data which can ensure the uniformity of the tire.

  The present disclosure takes the following measures in order to achieve the above object.

That is, the method of modifying the tire FEM model data of the present disclosure includes:
In the tire FEM model data, a group is set for an element, and a property is set for the group. Elements defined by four nodes are arranged in one row and belong to the same group, and between the nodes. An anisotropic element group in which anisotropic properties having different physical properties are set according to the orientation of the surface has an anisotropic element group, and elements belonging to the anisotropic element group are arranged between nodes according to the definition order of the nodes. The orientation of the surface is set,
For the anisotropic element group, identifying elements at both ends based on a group of adjacent elements,
In the tire meridian cross-section, when the axis along the tire inner surface from the tire equator to the toe is the S coordinate, and the axis along the tire thickness direction from the tire inner surface to the tire outer surface is the T coordinate, Identifying the first element among the identified elements at both ends based on at least one of the condition that the S coordinate is small or the T coordinate is small;
Modifying all the elements constituting the anisotropic element group in order from the first element to the terminal element which is the other end so that the definition order of each of the four nodes is the same;
including.

An apparatus for correcting tire FEM model data of the present disclosure includes:
In the tire FEM model data, a group is set for an element, and a property is set for the group. Elements defined by four nodes are arranged in one row and belong to the same group, and between the nodes. An anisotropic element group in which anisotropic properties having different physical properties are set according to the orientation of the surface has an anisotropic element group, and elements belonging to the anisotropic element group are arranged between nodes according to the definition order of the nodes. The orientation of the surface is set,
For the anisotropic element group, a both-ends element specifying unit that specifies both end elements based on a group of adjacent elements,
In the tire meridian cross-section, when the axis along the tire inner surface from the tire equator to the toe is the S coordinate, and the axis along the tire thickness direction from the tire inner surface to the tire outer surface is the T coordinate, A first element specifying unit that specifies the first element among the specified elements at both ends based on at least one of the condition that the S coordinate is small or the T coordinate is small;
A correction unit for correcting all the elements constituting the anisotropic element group in order from the first element to the terminal element which is the other end so that the definition order of each of the four nodes is the same;
Is provided.

"No. 1 element" is the order in which, when the group of elements constituting the group is wound up at the bead portion, advance from the tire equator to the bead portion, turn back at the bead portion, and proceed on the tire outer surface side to the tire equator. Means the element that is the most upstream in the group, and if the group of elements that make up the group is not wound up at the bead, it is viewed in order from the tire equator to the bead. Means the most upstream element in the group.
Since the shapes of the members of the tire model and the arrangement positions thereof are variously different, it is difficult to provide a correction logic corresponding to all tire models with the XYZ coordinates. The automatic correction logic that corrects the definition order of the nodes from the inner surface side of the tire to the outer surface side so as to be the same order can be provided, and as a result, the connectivity of the anisotropic element group can be secured.

FIG. 1 is a block diagram illustrating an apparatus for correcting tire FEM model data according to a first embodiment of the present disclosure. The figure which shows an example of tire FEM model data. FIG. 4 is an explanatory diagram regarding an anisotropic element group for which an anisotropic property is set. FIG. 9 is an explanatory diagram regarding a problem that occurs in an anisotropic element group for which an anisotropic property is set. 9 is a flowchart illustrating a model correction process according to the first embodiment. FIG. 7 is a block diagram showing an apparatus for correcting tire FEM model data according to a second embodiment. FIG. 4 is an explanatory diagram relating to boundary conditions set in tire FEM model data. 9 is a flowchart illustrating a model correction process according to the second embodiment.

<First embodiment>
Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings.

[Apparatus for correcting tire FEM model data]
The device 1 according to the present disclosure is a device that corrects existing tire FEM model data.
Specifically, as shown in FIG. 1, the device 1 includes a model acquisition unit 10, a both-ends element identification unit 11, a first element identification unit 12, a bead core center identification unit 13, a winding determination unit 14, a correction A part 15. These units 10 to 15 are realized by software and hardware in cooperation with each other in a data processing device such as a personal computer having a CPU, a memory, and various interfaces by the CPU executing a processing routine (not shown) stored in advance. Is done.

  The model acquiring unit 10 shown in FIG. 1 acquires tire FEM model data as shown in FIG. It is conceivable that when the user changes the model data created in advance and performs a save operation, the model data after the change is acquired in order to perform a correction process by the present apparatus. Of course, the model acquiring unit 10 may automatically generate the FEM model from the drawing data according to a predetermined procedure.

  The element group to be corrected in the tire FEM model is an anisotropic element group. When there are a plurality of anisotropic element groups, all the anisotropic element groups are sequentially corrected. As shown in FIG. 3, in the present embodiment, the correction target is an anisotropic element group SS1, SS2, SS3, SS4, SS5 representing a fiber member, and specifically, an anisotropic element group representing a belt. SS1, an anisotropic element group SS representing a carcass ply, an anisotropic element group SS3, SS4, SS5 representing a chaher, and the like. Of course, the present invention is not limited to these three, and differs depending on the tire FEM model. Other examples of the member serving as the anisotropic element include a cap ply, an edge ply, a side ply, and a chipper. In the tire FEM model data, as shown in FIGS. 2 and 3, groups are set for the elements, and properties are set for the groups. The anisotropic element group is arranged in a band shape in the tire meridian section, and specifically, is an element group in which elements defined by four nodes are arranged in one row and belong to the same group. In the group of the anisotropic element group, anisotropic properties having different physical properties are set according to the direction of the plane between the nodes. In the example of FIG. 3, the belt is constituted by one group (group # 1), and is represented by an anisotropic element group SS1. The carcass ply is composed of one group (group # 2) and is represented by an anisotropic element group SS2. The chaher is composed of a plurality of (three in this embodiment) groups (group # 3, group # 4, group # 5), and is represented by three anisotropic element groups SS3, SS4, and SS5. In addition, in the example of FIG. 3, for convenience of description, the chafer is configured by a plurality of groups, but another fiber member may be configured by a plurality of groups.

  As shown in FIG. 3, for the elements belonging to the anisotropic element group, the directions of the surfaces between the nodes are set in accordance with the definition order of the four nodes. As a preferred order, the first node n1, the second node n2, the third node n3, and the fourth node n4 are set in this order. A face (face # 1) is defined between the first node n1 and the second node n2 in the direction of the arrow. Between the second node n2 and the third node n3, a face (face # 2) is defined in the direction of the arrow. A surface (face # 3) is defined between the third node n3 and the fourth node n4 in the direction of the arrow. A surface (face # 4) is defined between the fourth node n4 and the first node n1 in the direction of the arrow. For example, it is preferable that face # 1 is set on the tire inner surface side, face # 2 is set on the bead side, face # 3 is set on the tire outer surface side, and face # 4 is set on the tire equator side. However, in the element group continuous from the tire inner surface side, the portion wound up by the bead core is not limited to this.

The end element specifying unit 11 illustrated in FIG. 1 specifies the elements S ₁ and _SN at both ends of the anisotropic element group (for example, SS2) based on the group of adjacent elements. N is the number of elements constituting the anisotropic element group (the number of elements belonging to the same group). Specifically, the determination is performed for all elements S _i (i = 1 to N) that constitute the anisotropic element group SS2. If the element of interest refers to the group of four adjacent elements adjacent to S _i, a group of three adjacent elements are different groups, it is determined that the element of interest S _i is an element of both ends. Otherwise, it is determined that the element of interest _Si is not an element at both ends.

No. 1 element identification unit 12 shown in FIG. 1, the No. 1 element S ₁ of the two ends Element S ₁ across a specific portion 11 has _identified, S _N, at least in that it or T coordinate S coordinate smaller the Specify based on any of the conditions. In the present specification, the “first element” means that when an element group constituting a group is wound up at a bead portion, the tire proceeds from the tire equator to the bead portion, is folded at the bead portion, and the tire outer surface side is a tire. When viewed from the equator order, this means the element that is the most upstream in the group.If the group of elements that make up the group is not rolled up at the bead part, from the tire equator side to the bead part side When viewed in the order of progress, it means the element that is the most upstream in the group. As shown in FIG. 2, the S coordinate is an axis along the tire inner surface from the tire equator CL to the toe in the tire meridian section. The T coordinate is an axis along the tire thickness direction from the inner surface of the tire to the outer surface of the tire. For example, the portion of the tire equator CL on the inner surface of the tire can be represented by (S, T) = (0, 0).

  The first element specifying unit 12 performs different processing depending on whether the anisotropic element group is wound around the bead core 2. For this purpose, a bead core center specifying unit 13 and a winding determining unit 14 are provided.

  The bead core center specifying unit 13 illustrated in FIG. 1 specifies the S coordinate of the center 2c of the bead core 2. The bead core 2 has characteristics such as a polygon such as a quadrangle and a hexagon, a circle or an ellipse. The bead core 2 is specified by the characteristics of the member shape. Also, the approximate position of the bead portion can be determined from the data on the tire size, and matching can be performed based on the shape characteristics.

The winding determination unit 14 shown in FIG. 1 determines whether or not the anisotropic element group has been wound around the bead core. Specifically, the S coordinates of both ends S ₁ and _SN of the anisotropic element group are smaller than the S coordinates of the center 2 c of the bead core 2, and all the elements S _i (i = 1 to N), it is determined whether the condition that an S coordinate larger than the S coordinate of the center 2c of the bead core 2 exists is satisfied. When the condition is satisfied, it is determined that the anisotropic element group is wound around the bead core. When the condition is not satisfied, it is determined that the anisotropic element group is not wound around the bead core. In the present embodiment, only the S coordinate of the first node constituting the element is set as the comparison target, but the S coordinate of any of the first to fourth nodes may be set as the comparison target.

No. 1 element specifying section 12, when the anisotropic element group to be corrected by winding up judgment unit 14 is determined not to wound the bead core, towards S coordinate is small is No. 1 element S ₁ And specify. This is because, when not wound around the bead core, the determination can be made only by the magnitude of the S coordinate. This is difficult to determine in a normal XYZ coordinate system.

  On the other hand, when the winding determining unit 14 determines that the anisotropic element group to be corrected is wound around the bead core, the first element specifying unit 12 determines that the smaller T coordinate is the first element. And specify. This is because, when the bead core is wound, the T-coordinate of the winding end is always larger than the inner surface of the tire, so that it can be determined only by the magnitude of the T-coordinate. This is difficult to determine in a normal XYZ coordinate system.

The correction unit 15 illustrated in FIG. 1 sequentially performs, for all the elements S _i (i = 1 to N) configuring the anisotropic element group to be corrected, from the first element S ₁ to the terminal element _SN which is the other end. , So that the definition order of each of the four nodes n1, n2, n3, and n4 is the same. In this way, as shown in FIG. 3, the directions of the surfaces between the nodes of the elements of the anisotropic element group are aligned.

As shown in FIG. 3, one fiber member (Cheach in the figure) is represented by a plurality of anisotropic element groups SS3, SS4, and SS5 in the tire FEM model data. , SS4 and SS5 may be continuously arranged in one row. In this case, the correction unit 15 corrects the number one element S ₁ to the termination element S _N is completed, when the adjacent element at the end element S _N belongs to another anisotropic element group, said abutment element Is the first element, the order of defining the nodes is modified for the other anisotropic element group, and the modification of the other anisotropic element group is changed so that the element adjacent to the terminal element _SN becomes another anisotropic element group. Repeat until no longer belongs.

In the example case shown in FIG. 3, if the modified from 1st element S ₁ of the anisotropic element group SS3 to the termination element S _N is completed, the adjacent element at the end element S _N of the anisotropic element group SS3, other Exists in the anisotropic element group SS4. Therefore, detects this, the other anisotropic element group SS4 the detected adjacent elements as No. 1 element S ₁ to modify the definition order of nodes. If modified from 1st element S ₁ of the anisotropic element group SS4 to the termination element S _N is completed, the termination element S _N of the anisotropic element group SS4 to adjacent elements, the other anisotropic element group SS5 There is an element to which it belongs. Therefore, detects this, the other anisotropic element group SS5 the detected adjacent elements as No. 1 element S ₁ to modify the definition order of nodes. If modified from 1st element S ₁ of the anisotropic element group SS5 to the termination element S _N is completed, the adjacent element at the end element S _N of the anisotropic element group SS5 belongs to another anisotropic element group Since the element does not exist, the processing ends. As the adjacent direction, setting a detection direction such as the side of the surface (face # 2) between the second node and the third node may be mentioned.

  For example, the model acquisition unit 10 generates the square elements from the small value to the large value of the S coordinate and the rectangular element from the small value to the large value of the T coordinate, and defines the node as the one from the small S coordinate to the large S coordinate. It is conceivable to do so. Then, as shown in FIG. 4, the direction of the surface may be reversed at the winding end portion around the bead core 2. The above correction is particularly effective for the tire FEM model data generated in this manner.

[Method of modifying tire FEM model data]
A method for correcting the tire FEM model data using the device 1 will be described with reference to FIG. A case where the anisotropic element group SS2 representing the carcass ply is corrected will be described.

  First, in step S100, the model acquisition unit 10 acquires tire FEM model data to be corrected. In the tire FEM model data, a group is set for an element, and a property is set for the group. Elements defined by four nodes are arranged in one row, belong to the same group, and have There is an anisotropic element group SS2 in which anisotropic properties having different physical properties are set according to the orientation of the surface. For the elements belonging to the anisotropic element group SS2, the direction of the plane between the nodes is set according to the order of defining the nodes.

  Steps S101 to S109 are executed for each anisotropic element group.

In the next step S101, the both ends element specifying unit 11 specifies the elements S ₁ and _SN at both ends of the target anisotropic element group SS2 based on the group of the adjacent elements.

  In the next step S102, the bead core center specifying unit 13 specifies the S coordinate of the center 2c of the bead core 2.

In the next step S103, the winding determination unit 14 determines that the S coordinates of the two end elements S ₁ and _SN of the anisotropic element group SS2 are smaller than the S coordinate of the center 2c of the bead core 2 and that the anisotropic element group SS2 If the condition that any of the elements constituting S has an S coordinate larger than the S coordinate of the center 2c of the bead core 2 is satisfied, it is determined that the anisotropic element group SS2 is wound around the bead core. If the condition is not satisfied, it is determined that the anisotropic element group SS2 is not wound around the bead core.

Next, the No. 1 element specifying section 12, when the anisotropic element group SS2 is determined to be wound up on the bead core 2 (S104: YES), who T coordinates is small is No. 1 element _{S 1} (S105). Meanwhile, No. 1 element identification unit 12, when the anisotropic element group SS2 is determined not wound up on the bead core (S104: NO), identified as better S coordinate is small is number one element S ₁ (S106).

In the next step S107, correction unit 15, for all the elements _S i configuring the anisotropic element group SS2 to be corrected (i = 1 to N), the terminating element S from No. 1 element _{S 1} is the other end Up to _N , the four nodes n1, n2, n3, and n4 are modified so that the definition order is the same. The definition order of the nodes of the element of interest S _i is checked, and if the definition order is not the predetermined order, it is corrected. If the definition order is the predetermined order, the element of interest S _i may be set to the next element S _{i + 1} .

In the above description, the processing target is the anisotropic element group SS2, but the following is assumed to be the anisotropic element group SS3 for convenience of explanation. In step S107, the modified from 1st element _{S 1} of the anisotropic element group SS3 to the termination element _{S N} is completed, at the next step S108, the adjacent element at the end element _{S N} belongs to another anisotropic element group Is determined. If it belongs (S108: YES), the adjacent element is set as the first element, and the definition order of the nodes in the other anisotropic element group SS4 is corrected (step S109). The other anisotropic element groups SS4 and SS5 performed in step S109 are repeatedly executed until the element adjacent to the terminal element _SN does not belong to another anisotropic element group (S108: NO).

As described above, the method of correcting the tire FEM model data of the present embodiment is as follows.
In the tire FEM model data, a group is set for an element, and a property is set for the group. Elements defined by four nodes are arranged in one row and belong to the same group, and between the nodes. It has an anisotropic element group SS2 in which anisotropic properties having different physical properties are set according to the direction of the surface. Elements belonging to the anisotropic element group SS2 include nodes n1, n2, n3, and n4. The orientation of the surface between the nodes is set according to the definition order,
A step (S101) of specifying elements S ₁ and _SN at both ends based on a group of adjacent elements for the anisotropic element group SS2;
In the tire meridian section, when the axis along the tire inner surface from the tire equator CL to the toe is the S coordinate, and the axis along the tire thickness direction from the tire inner surface to the tire outer surface is the T coordinate, No. 1 element _{S 1} of the elements _S 1, _{S N} of the specified ends, the step (S104, S105, S106) specific for based on at least one of the conditions that can or T coordinate S coordinate is small is small,
For all elements _S i configuring the anisotropic element group SS2 (i = 1~N), in order from the No. 1 element _{S 1} to the termination element _{S N} which is the other end, each of the four nodes n1, n2, n3, modifying the definition order of n4 to be the same (S107);
including.

The device 1 for correcting the tire FEM model data of the present embodiment includes:
In the tire FEM model data, a group is set for an element, and a property is set for the group. Elements defined by four nodes are arranged in one row and belong to the same group, and between the nodes. It has an anisotropic element group SS2 in which anisotropic properties having different physical properties are set according to the direction of the surface. Elements belonging to the anisotropic element group SS2 include nodes n1, n2, n3, and n4. The orientation of the surface between the nodes is set according to the definition order,
To anisotropic element group SS2, and both end element identification unit 11 for identifying the elements S _1, S _N ends based on the group of adjacent elements,
In the tire meridian section, when the axis along the tire inner surface from the tire equator CL to the toe is the S coordinate, and the axis along the tire thickness direction from the tire inner surface to the tire outer surface is the T coordinate, A first element specifying unit 12 that specifies the first element S ₁ among the specified elements S ₁ and _SN at both ends based on at least one of the condition that the S coordinate is small or the T coordinate is small;
For all elements _S i configuring the anisotropic element group SS2 (i = 1~N), in order from the No. 1 element _{S 1} to the termination element _{S N} which is the other end, each of the four nodes n1, n2, n3, a modifying unit 15 for modifying the definition order of n4 to be the same,
Is provided.

  Since the shapes of the members of the tire model and the arrangement positions thereof are variously different, it is difficult to provide a correction logic corresponding to all tire models with the XYZ coordinates. For SS2, it is possible to provide an automatic correction logic for correcting the definition order of the nodes from the tire inner surface side to the outer surface side so as to be the same order, and as a result, it is possible to secure the connectivity of the anisotropic element group. .

In the method of the present embodiment,
A step of identifying the S coordinate of the center 2c of the bead core 2 (S102);
The S-coordinate of both end elements S ₁ , _SN of the anisotropic element group SS2 is smaller than the S-coordinate of the center 2c of the bead core 2, and one of the elements constituting the anisotropic element group SS2 has the bead core 2 If the condition that there is an S coordinate larger than the S coordinate of the center 2c is met, it is determined that the anisotropic element group SS2 is wound around the bead core 2, and if the condition is not met, the anisotropic element group SS2 is anisotropic. A step of determining that the element group SS2 is not wound around the bead core 2 (S103);
Including
In the step of specifying the _first element S1 (S104, S105, S106), when it is determined that the anisotropic element group SS2 is wound up around the bead core 2 (S104: YES), the smaller T coordinate is used. When it is determined that the element S1 is the _first element S1 (S105) and it is determined that the anisotropic element group SS2 is not wound around the bead core 2 (S104: NO), the one having the smaller S coordinate is the first element S. It is specified that it is ₁ (S106).

In the device of the present embodiment,
A bead core center specifying unit 13 for specifying the S coordinate of the center 2c of the bead core 2;
The S-coordinate of both end elements S ₁ , _SN of the anisotropic element group SS2 is smaller than the S-coordinate of the center 2c of the bead core 2, and one of the elements constituting the anisotropic element group SS2 has the bead core 2 If the condition that there is an S coordinate larger than the S coordinate of the center 2c is met, it is determined that the anisotropic element group SS2 is wound around the bead core 2, and if the condition is not met, the anisotropic element group SS2 is anisotropic. A winding determination unit 14 that determines that the element group SS2 is not wound around the bead core 2,
With
No. 1 element specifying unit 12, anisotropic element group SS2 is when it is determined that the wound bead cores 2, identified as better T coordinates is small is number one element S ₁ by winding up judgment unit 14 When it is determined that the anisotropic element group SS2 is not wound up around the bead core 2, the one having the smaller S coordinate is identified as the _first element S1.

In particular, the member (chach) wound up on the bead core is not necessarily processed through the tire equator CL, so that the processing is difficult. However, according to the method and the apparatus of the present embodiment, the presence or absence of the winding on the bead core 2 is determined, and the characteristics of the member arrangement pattern according to the presence or absence of the winding are used, so that appropriate recognition can be performed. For example, as Cheha shown in FIG. 3, even when the S coordinate of the terminating element S _N than No. 1 element S ₁ which is the other end is small, can be recognized properly No.1 element S _1.

The program according to the present embodiment is a program that causes a computer to execute each step of the method.
By executing these programs, it is also possible to obtain the operational effects of the above method. In other words, it can be said that the above method is used.

  As described above, the embodiments of the present disclosure have been described with reference to the drawings. However, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present disclosure is shown not only by the description of the embodiment but also by the claims, and further includes meanings equivalent to the claims and all modifications within the scope.

<Second embodiment>
Hereinafter, a second embodiment of the present disclosure will be described with reference to the drawings. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

[Apparatus for correcting tire FEM model data]
The device 2 according to the present disclosure is a device that corrects existing tire FEM model data.
Specifically, as illustrated in FIG. 6, the device 2 includes a model acquisition unit 10, an element group identification unit 21, and an identifier correction unit 22. In each of the units 10, 21, and 22, the software and hardware cooperate with each other by executing a processing routine (not shown) stored in advance by the CPU in an information processing device such as a personal computer having a CPU, a memory, various interfaces, and the like. Is realized.

  The model acquisition unit 10 is the same as in the first embodiment. As shown in FIG. 7, the tire FEM model data has an element defined by a plurality of nodes. The identifier of the surface between the nodes is defined according to the definition order of the nodes. The identifiers set in the definition order are the same as in the first embodiment. As shown in FIG. 7, the tire FEM model data includes a surface on which internal pressure is applied (indicated by a dashed line), a contact candidate node (indicated by an arrow) that forms a contact surface that can contact the road surface, and contact with the rim. A contact candidate node (shown by a circle) that forms a possible contact candidate surface is set as a boundary condition. Of course, it is sufficient that at least one of the boundary conditions is set. The identifier of the surface to which the internal pressure is applied is face # 1 defined between the first node and the second node, and the identifier of the surface between the contact candidate nodes and the identifier of the surface between the contact candidate nodes are the third node and the third node. Face # 3 defined between four nodes. In the present embodiment, the identifier is a surface number, and the identifier is not limited to the example of FIG.

  The element group specifying unit 21 illustrated in FIG. 6 specifies an element group for which the above boundary conditions have been set.

  The identifier correcting unit 22 shown in FIG. 6 is configured such that, for all the elements constituting the element group specified by the element group specifying unit 21, the identifiers of the surfaces between the nodes for which the boundary conditions are set become predetermined identifiers corresponding to the boundary conditions. Modify the node definition order so that For example, the order of defining the nodes is corrected so that the identifier of the surface to which the internal pressure is applied is face # 1. The order of defining the nodes is modified so that the identifiers of the surfaces between the grounding candidate nodes and the identifiers of the surfaces between the contact candidate nodes become face # 3.

[Method of modifying tire FEM model data]
A method for correcting the tire FEM model data using the device 2 will be described with reference to FIG. First, in step S201, the model acquisition unit 10 acquires tire FEM model data to be corrected. Steps S202 to S203 are executed for each boundary condition. In step S202, the element group identification unit 21 identifies an element group for which the above boundary conditions have been set. In the next step S203, the identifier correcting unit 22 determines, for all the elements constituting the element group specified by the element group specifying unit 21, the identifiers of the surfaces between the nodes for which the boundary conditions are set corresponding to the predetermined boundary conditions. Modify the order of defining nodes so that they become identifiers.

  In this way, the identifier of the tire inner surface to which the internal pressure is applied, the contact candidate surface, or the contact candidate surface with the rim is unified to the identifier corresponding to the boundary condition. With such uniformity, the value of the simulation result can be obtained by the identifier of the surface without confirming the orientation of the element for each element, and the post-processing is facilitated. Particularly, the identifier (face # 1) of the inner surface of the tire such as the surface to which the internal pressure is applied is corrected so as to be unified with the identifier (face # 3) of the outer surface of the tire that is in contact with the ground. The connectivity of the elements is unified, making it easier to handle calculation results such as ground distribution.

  The structure adopted in each of the above embodiments can be adopted in any other embodiment. The specific configuration of each unit is not limited to only the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure.

DESCRIPTION OF SYMBOLS 11 ... Both-ends element specification part 12 ... No. 1 element specification part 13 ... Bead core center specification part 14 ... Winding determination part 15 ... Correction part 21 ... Element group specification part 22 ... Identifier correction part

Claims (9)

A method in which a computer modifies tire FEM model data,
In the tire FEM model data, a group is set for an element, and a property is set for the group. Elements defined by four nodes are arranged in one row and belong to the same group, and between the nodes. An anisotropic element group in which anisotropic properties having different physical properties are set according to the orientation of the surface has an anisotropic element group, and elements belonging to the anisotropic element group are internodes according to the definition order of the nodes. Surface orientation is set,
For the anisotropic element group, identifying elements at both ends based on a group of adjacent elements,
In the tire meridian cross-section, when the axis along the tire inner surface from the tire equator to the toe is the S coordinate, and the axis along the tire thickness direction from the tire inner surface to the tire outer surface is the T coordinate, Identifying the first element among the identified elements at both ends based on at least one of the condition that the S coordinate is small or the T coordinate is small;
Modifying all the elements constituting the anisotropic element group in order from the first element to the terminal element which is the other end so that the definition order of each of the four nodes is the same;
A method for modifying tire FEM model data, comprising: Identifying the S coordinate of the center of the bead core;
The S coordinate of both end elements of the anisotropic element group is smaller than the S coordinate of the center of the bead core, and any of the elements constituting the anisotropic element group has an S coordinate smaller than the S coordinate of the center of the bead core. When the condition that a large S coordinate exists is satisfied, it is determined that the anisotropic element group is wound around the bead core. When the condition is not satisfied, the anisotropic element group is wound around the bead core. Determining that the user has not been
Including
The step of specifying the first element includes, when it is determined that the anisotropic element group is wound around the bead core, specifying that the smaller T coordinate is the first element, The method according to claim 1, wherein when it is determined that the group is not wound around the bead core, the one having the smaller S coordinate is identified as the first element. The tire FEM model data has a plurality of the anisotropic element groups arranged in one row,
When the modification from the first element to the terminal element is completed, and the adjacent element of the terminal element belongs to another anisotropic element group, the adjacent element is regarded as the first element and a node is set for the other anisotropic element group. 3. The method according to claim 1, further comprising the step of: modifying the definition order of the terminating elements, wherein the modification of the another anisotropic element group is repeatedly performed until an element adjacent to the terminal element does not belong to another anisotropic element group. The method described in. An apparatus for correcting tire FEM model data,
In the tire FEM model data, a group is set for an element, and a property is set for the group. Elements defined by four nodes are arranged in one row and belong to the same group, and between the nodes. An anisotropic element group in which anisotropic properties having different physical properties are set according to the orientation of the surface has an anisotropic element group, and elements belonging to the anisotropic element group are arranged between nodes according to the definition order of the nodes. The orientation of the surface is set,
For the anisotropic element group, a both-ends element specifying unit that specifies both end elements based on a group of adjacent elements,
In the tire meridian cross-section, when the axis along the tire inner surface from the tire equator to the toe is the S coordinate, and the axis along the tire thickness direction from the tire inner surface to the tire outer surface is the T coordinate, A first element specifying unit that specifies the first element among the specified elements at both ends based on at least one of the condition that the S coordinate is small or the T coordinate is small;
A correction unit for correcting all the elements constituting the anisotropic element group in order from the first element to the terminal element which is the other end so that the definition order of each of the four nodes is the same;
An apparatus for correcting tire FEM model data, comprising: A bead core center specifying part for specifying the S coordinate of the center of the bead core;
The S coordinate of both end elements of the anisotropic element group is smaller than the S coordinate of the center of the bead core, and any of the elements constituting the anisotropic element group has an S coordinate smaller than the S coordinate of the center of the bead core. When the condition that a large S coordinate exists is satisfied, it is determined that the anisotropic element group is wound around the bead core. When the condition is not satisfied, the anisotropic element group is wound around the bead core. A winding determination unit that determines that the
With
The first element specifying unit, when the winding determination unit determines that the anisotropic element group is wound around the bead core, specifies that the one with the smaller T coordinate is the first element, and The device according to claim 4, wherein when it is determined that the isotropic element group is not wound around the bead core, the one having the smaller S coordinate is identified as the first element. The tire FEM model data has a plurality of the anisotropic element groups arranged in one row,
When the correction from the first element to the terminal element is completed, and the adjacent element of the terminal element belongs to another anisotropic element group, the correction unit sets the adjacent element as the first element and the other anisotropic element. The order in which nodes are defined for a group of sex elements is corrected, and the correction of the another group of anisotropic elements is repeatedly performed until an element adjacent to the terminal element no longer belongs to another group of anisotropic elements. An apparatus according to claim 5. A method in which a computer modifies tire FEM model data,
The tire FEM model data has an element defined by a plurality of nodes, and an identifier of a surface between the nodes is defined according to the definition order of the nodes. A ground contact candidate node forming a surface, and at least one of boundary conditions of a contact candidate node forming a contact candidate surface that can make contact with the rim, are set,
Identifying an element group for which the boundary condition has been set;
Modifying the definition order of the nodes such that the identifiers of the surfaces between the nodes for which the boundary conditions are set are the predetermined identifiers corresponding to the boundary conditions, for all the elements constituting the specified element group,
A method for modifying tire FEM model data, comprising: An apparatus for correcting tire FEM model data,
The tire FEM model data has an element defined by a plurality of nodes, and an identifier of a surface between the nodes is defined according to the definition order of the nodes. A ground contact candidate node forming a surface, and at least one of the boundary conditions of a contact candidate node forming a contact candidate surface that can make contact with the rim, are set,
An element group specifying unit that specifies an element group for which the boundary condition is set;
For all the elements constituting the element group specified by the element group specifying unit, the order of defining the nodes is changed so that the identifier of the surface between the nodes for which the boundary condition is set becomes a predetermined identifier corresponding to the boundary condition. An identifier correcting unit to be corrected;
An apparatus for correcting tire FEM model data, comprising:   A program for causing a computer to execute the method according to claim 1.

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