JP7292806B2 - Fluid analysis method around tire, fluid analysis system and program around tire - Google Patents

Description

The present disclosure relates to a fluid analysis method around a tire, a fluid analysis system around a tire, and a program.

In recent years, fluid analysis simulations around tires have been proposed to evaluate performance such as noise performance, drainage performance, and air resistance due to fluids (air, water, etc.) around tires. In the simulation, the fluid region in which the fluid is defined should be set according to the ground shape of the tire model. In Patent Document 1, time-series data relating to displacement of tire model nodes due to tire deformation and rotation is acquired by structural calculation, and this time-series data is used for deformation of computational grid cells of a fluid analysis model to execute fluid analysis calculations. It is stated that

JP 2018-197066 A

Since fluid analysis calculations take time, further speeding up is required.

The present disclosure provides a tire-surrounding fluid analysis method, a tire-surrounding fluid analysis system, and a program capable of reducing calculation time.

A fluid analysis method around a tire according to the present disclosure is a method executed by one or more processors, in which grooves formed on a ground contact surface are analyzed under analysis conditions including a predetermined load, a predetermined internal pressure, and a predetermined rotational speed. rolling a first model that expresses a tire having a plurality of elements and nodes, calculating deformation of the first model due to contact with the road surface by numerical calculation; and tire including grooves in the first model performing a grouping process on a plurality of surfaces constituting an outer surface, with two or more continuous surfaces meeting a predetermined bonding condition as one group surface; and forming each of the group surfaces. Acquiring time-series data on the displacement between the first node at the intersection of the outermost sides and the second node that constitutes each ungrouped surface from the deformation calculation result of the first model; Using a second model in which the space around the tire including the outer surface of the tire and the road surface is represented by a plurality of computational grid cells, the positions of the computational grid cells with the first node and the second node in the time-series data as control points and performing a fluid analysis calculation for calculating the physical quantity of the fluid for each of the computational grid cells while changing .

According to this configuration, two or more continuous faces that meet the predetermined joining condition are taken as one group face. Since the first node at the intersection of the outermost sides of all the nodes forming the group surface is used as the control point, the number of control points is greater than when all the nodes forming the group surface are used as control points. can be reduced, the calculation cost of deformation processing of computational grid cells can be reduced, and the calculation time can be shortened. Moreover, there are cases where it is possible to suppress deterioration of calculation accuracy or calculation failure by using a predetermined connection condition.

Block diagram showing a fluid analysis system around a tire of the present disclosure Perspective view showing an example of a tire finite element method model Perspective view showing tire finite element method model with groove space element Schematic diagram showing groove cross section of tire finite element method model and schematic diagram showing groove cross section of tire finite element method model with groove spatial element Explanatory diagram of grouping process Explanatory diagram of join conditions in grouping processing Explanatory diagram for contact rolling analysis and diagram showing only groove space elements Diagram showing an example of a fluid analysis model around a tire Enlarged view showing the main part in FIG. Explanatory diagram of mesh morphing after grouping Explanatory diagram for mesh morphing without grouping Diagram showing faces before grouping and faces after grouping Tire meridian end view showing surfaces belonging to the first surface group and the second surface group Tire meridian end view showing surfaces belonging to the first surface group and the second surface group Flowchart showing a fluid analysis method according to the present disclosure

An embodiment of the present disclosure will be described below with reference to the drawings.

[Fluid analysis system around tires]
A fluid analysis system 1 according to this embodiment simulates the behavior of a fluid around a tire. Specifically, as shown in FIG. 1, the fluid analysis system 1 includes a memory 1a, a structure calculation unit 12, a grouping processing execution unit 11, a time series data acquisition unit 13, and a fluid calculation unit 14. have. The fluid analysis system 1 may further have a model generator 10 . These units 10 to 14 cooperate with software and hardware by executing the processing routine of FIG. It works and is realized.

The memory 1a shown in FIG. 1 stores a tire finite element method model M2 with groove space elements used for contact rolling analysis. The tire finite element method model M2 with groove space elements is, as shown in FIG. a channel space element 30 located in the channel space surrounded by the channel walls forming 20; The groove space element 30 is bonded to the groove wall surface forming the groove 20 so as not to peel off due to rolling. The tire finite element method model M2 with groove space elements is a model in which groove space elements 30 are provided in the tire finite element method model M1 having the tread pattern (grooves 20) shown in FIG. 2A. In many cases, there are a plurality of grooves 20, such as a main groove extending in the tire circumferential direction and a lateral groove crossing the tire circumferential direction. In the example shown in FIG. 2B, the groove space elements 30 are set for all the grooves, but it is not necessary to set the groove space elements 30 for all the grooves. . For example, the groove space element 30 may be set only for grooves (slits, sipes) that are lateral grooves intersecting in the circumferential direction and whose groove width is equal to or smaller than a certain value. In this embodiment, the tire finite element method model M2 with groove spatial elements is the object of simulation, but the simulation object is the tire finite element method model M1, and the tire finite element method model M1 is stored in the memory 1a. good too.

The upper part of FIG. 3 is a schematic diagram showing a groove cross section of the tire finite element method model M1. A groove wall surface 21 forming the groove 20 is represented by a plurality of node points P0 (indicated by circles in the figure). A tire outer surface 22 (ground contact surface in FIG. 3) other than the grooves 20 is represented by a plurality of node points P0. The lower part of FIG. 3 is a schematic diagram showing a groove cross-section of a tire finite element method model M2 with groove space elements. A groove space element 30 is represented by a plurality of nodes P3 (indicated by triangles in the figure). On the groove wall surface 21, a node point P3 forming a groove space element 30 is set together with a node point P0 forming a tire outer surface (groove wall surface 21, ground contact surface 22).

In this embodiment, a model generator 10 is provided. A general tire finite element method model M1 shown in FIG. 2A is generated or acquired from the outside, and then the model generation unit 10 inserts the groove space element 30 into a predetermined groove of the tire finite element method model M1. A tire finite element method model M2 with spatial elements is generated. Although the model generation unit 10 is provided in this embodiment, the model generation unit 10 can be omitted if the tire finite element method model M2 with groove space elements is obtained. Further, when the tire finite element method model M1 is to be simulated, the model generator 10 can be omitted if the tire finite element method model M1 is obtained.

The physical properties of the groove space element 30 can be set arbitrarily, but are preferably set as follows. The Young's modulus of the groove space element 30 is set to 1/10000 or more and 1/1000 or less of the Young's modulus set to the element forming the ground contact surface, and the Poisson's ratio of the groove space element 30 is 0±0.01. is set to If the Young's modulus is small, the groove space element does not hinder the deformation of the groove, so it is possible to reduce or eliminate the influence on tire contact and rolling analysis. If the Young's modulus is reduced to a certain extent, the effect of not inhibiting groove deformation reaches a ceiling. If it is 1/1000 or less with respect to the elements of the tread portion forming the contact surface, the influence on accuracy can be ignored. The reason why the Poisson's ratio of the groove space element is 0±0.01 is that if the Poisson's ratio is 0, the volume simply changes with the deformation of the groove, so the Poisson's ratio of 0 is most preferable. Considering the level of distortion that can be obtained, an error of about ±0.01 is considered to have no effect on accuracy.

The structural calculation unit 12 shown in FIG. 1 generates a tire finite element method model M2 with groove space elements stored in the memory 1a under analysis conditions including a predetermined load, a predetermined internal pressure, and a predetermined rotational speed. The model M2 is rolled as shown in the upper part of 6, and the deformation of the model M2 caused by the contact with the road surface is calculated by numerical calculation. Specifically, the tire model M2 is mounted on the rim, and internal pressure is applied, and the tire model M2 is pressed against the road surface and rotated. The lower part of FIG. 6 shows only the groove space element 30. As shown in FIG. The deformation of the model M2 includes deformation of the groove space element 30 as well as the outer tire surface including the groove walls. Through this rolling analysis, the contact pressure generated by contact with the road surface is calculated, and the deformation of the tire (groove 20 and groove space element 30) due to the pressure value is calculated along the time axis. A detailed description of this rolling analysis is omitted. In this embodiment, the object of simulation is the tire finite element method model M2 with groove space elements, but the tire finite element method model M1 without the groove space elements 30 may be the object of simulation.

The grouping process execution unit 11 shown in FIG. 1 selects two or more surfaces that meet a predetermined connection condition for a plurality of surfaces that constitute the tire outer surface including grooves in the tire finite element method model M2 with groove space elements. A grouping process is executed in which continuous faces are grouped as one group face. As shown in FIG. 5, the predetermined bonding condition in this embodiment is that the mutually adjacent surfaces (F01, F02) are parallel to each other, or that the mutually adjacent surfaces (F02, F03) are parallel to each other. is within a predetermined angle θ1. FIG. 5 shows a cross section perpendicular to sides (S01) [S02] between adjacent faces (F01, F02) [F02, F03]. 4 and 5 show an example in which a plurality of surfaces (F01 to 07) are flat surfaces and the sides (S01, S02, . . . ) that serve as boundary lines are straight lines; It may be a curved surface. The sides forming the surface may be curved surfaces. The predetermined angle θ1 is preferably set to 10 degrees or less in order to ensure accuracy. Even when comparing surfaces, it is possible to make a determination by comparing angles in a cross section orthogonal to a side.

The grouping process execution unit 11 repeats the process until there are no more combinations of faces that meet a predetermined joining condition. In the example of FIG. 4, two or more continuous planes F01, F02, F03, and F04 are determined as one group plane G01. Faces F05, F06, F07, and F08 are not grouped because they do not meet the predetermined joining conditions.

The time-series data acquisition unit 13 shown in FIG. 1 acquires time-series data for deforming the fluid analysis model used in the fluid analysis calculation from the deformation calculation result of the model M2. The time-series data acquisition unit 13 includes a first nodal data acquisition unit 13a, a second nodal data acquisition unit 13b, a third nodal data acquisition unit 13c, a nodal coordinate acquisition unit 13d, and a displacement vector calculation unit 13e. have. The third node data acquisition unit 13c can be omitted.

As time-series data, the first node data acquisition unit 13a acquires, as shown in FIG. Acquire data on the displacement of one node P1. The first node is the minimum number of nodes required to represent the group face (G01), is a node at the vertex of the group face, and has no nodes inside the group face. As time-series data, the second node data acquisition unit 13b acquires, as shown in FIG. get.

The time-series data is data relating to the displacement of the first node P1 and the second node P2 over the passage of unit time on the simulation. The displacement of the first node P1 and the second node P2, which constitute the tire outer surface, includes deformation due to grounding of the entire outer surface of the tire including the tire side surface, tire contact surface, and groove wall surface, positional movement due to rotation, is included. In other words, the time-series data is data representing how the tire surface including the grooves 20 moves.

The third node data acquisition unit 13c acquires, as time-series data, data relating to the displacement of at least some of the third nodes P3 among all the nodes forming the groove spatial element 30 shown in FIG. If the problem of calculation failure due to groove deformation is not addressed, the third nodal point data acquisition unit 13c may not be provided and the time series data may not include data on the displacement of the third nodal point P3. Of course, if the time-series data includes data on the displacement of all the third nodes P3 that make up the groove spatial element 30 as the third nodes P3, the number of nodes as control points increases, so that the quality of the computational grid cell can be improved. This makes it possible to enhance the effect of suppressing computational failure.

ここで、Ｖはベクトルを示し、ｔは単位時間を表すタイムステップ番号であり、ｃｏｏｄは座標を示し、ｘ、ｙ、ｚはそれぞれ方向成分を示す。
なお、本実施形態では、節点の変位に関する時系列データが上記の変位ベクトルであるとしているが、変位に関するデータであれば、これに限定されず、表現方法は種々変更可能である。 In this embodiment, the node coordinate acquisition unit 13d acquires the coordinates of the first node P1, the second node P2, and the third node P3 from the deformation calculation result of the model M2 every unit time. The displacement vector calculator 13e calculates a displacement vector for each unit time based on the coordinates before and after the unit time for all the nodes whose coordinate histories are extracted. A displacement vector is represented by the following formula (1).

Here, V indicates a vector, t is a time step number representing unit time, cood indicates coordinates, and x, y, and z indicate directional components.
In the present embodiment, the time-series data regarding the displacement of the node is the above-mentioned displacement vector.

The fluid calculation unit 14 shown in FIG. 1 executes fluid analysis calculations using the fluid analysis model and the time-series data. Specifically, using the fluid analysis model, the fluid calculation unit 14 uses the first node P1, the second node P2, and the third node P3 in the time-series data as control points while changing the position of the computational grid. A fluid analysis calculation is executed to calculate the physical quantity of the fluid for each cell. In other words, using time-series data that shows how the grooves and tire surface move, calculations are performed while deforming the computational grid cells for calculating the behavior of the fluid, and the physical quantities of the fluid are calculated. . As shown in FIGS. 7 and 8, a fluid analysis model is used in which the tire surrounding space including the tire outer surface and the road surface is represented by a plurality of computational grid cells. The tire surface shape of the fluid analysis model is created based on the tire finite element method model M2, which is a structural calculation model. In this embodiment, the overlapping grid method is used as the calculation method, but other methods may be adopted. As schematically explained in FIG. 9, the deformation of the computational grid cell C1, that is, the mesh morphing, provides a control point P4 for controlling the deformation of the computational grid cell C1, and the interpolation field ( A region surrounded by a dotted line in the drawing) is arranged to surround the computational grid cell C1, and the computational grid cell C1 in the interpolation field is deformed by proportional calculation according to the displacement of the control point. FIG. 10 shows an example in which a plurality of surfaces are not grouped, and 12 nodes P4 forming 6 surfaces are used as control points. FIG. 9 shows an example of grouping a plurality of faces, with six faces as one group face and four node points P4 constituting one group face as control points. It can be seen that the example in FIG. 9 reduces the number of control points compared to the example in FIG. 10 to reduce the calculation cost.

The grouping process execution unit 11 may perform the grouping process on all the surfaces forming the outer surface of the tire. However, in order to reduce the risk of calculation failure, it is better not to perform the grouping process on surfaces that cause a large change (deformation) in the space around the tire. Therefore, in the present embodiment, each surface constituting the tire outer surface belongs to either the first surface group Gp1 or the second surface group Gp2, and the surfaces belonging to the first surface group Gp1 are grouped. processing, and not grouping processing for surfaces belonging to the second surface group Gp2.

FIG. 12 is a tire meridional end view showing a setting example of the first surface group Gp1 and the second surface group Gp2. In the example shown in FIG. 12, the outer surface rotationally symmetric about the tire axis is a tire side surface such as a sidewall indicated by a dashed line, and belongs to the first surface group Gp1. The outer surfaces that are not rotationally symmetric about the tire axis are the ground contact surfaces indicated by solid lines and the groove wall surfaces that form the groove 20, and belong to the second surface group Gp2. The contact surface is composed of nodes (contact candidate points) that are candidates for contact with the road surface. A plane connecting contact candidate points is a ground plane. When the main groove 20 extending in the tire circumferential direction is parallel to the tire circumferential direction, the groove wall surface forming the main groove 20 may belong to the first surface group Gp1 as being rotationally symmetrical about the tire axis. Moreover, the ground-contacting surfaces having no lateral grooves in the tire circumferential direction may belong to the first surface group Gp1 assuming that they are rotationally symmetrical about the tire axis. In the present embodiment, the tire finite element method model M1 shown in FIG. 2A is generated by combining a tread model and a body model arranged radially inward of the tread model. The tread portion model is defined as a tread portion having a ground contact surface and grooves 20, and is generated by developing members defined as the tread portion in the tire circumferential direction. The body part model is generated by rotating and developing a member such as sidewall rubber defined as the body part in the tire circumferential direction. Each member constituting the tire finite element method model M1 has data indicating whether it is a tread portion or a body portion. The grouping process execution unit 11 refers to this data and determines whether or not to execute the grouping process.

FIG. 13 is a tire meridional end view showing another setting example of the first surface group Gp1 and the second surface group Gp2. As shown in FIG. 13 , the outer surface located on the outer side RD1 in the tire radial direction of the imaginary line L1 connecting the bottoms of the plurality of grooves 20 belongs to the second surface group Gp2. An outer surface located radially inward RD2 of the imaginary line L1 belongs to the first surface group Gp1.

[Fluid analysis method]
A fluid analysis method around a tire using the system 1 will be described with reference to FIG.

First, in step ST100, the memory 1a stores a tire finite element method model M2 that expresses a tire with a plurality of elements and nodes. A tire finite element method model M2 having groove space elements 30 arranged in the groove space is stored.

In the next step ST101, the structural calculation unit 12 causes the tire finite element method model M2 to roll under analysis conditions including a predetermined load, a predetermined internal pressure, and a predetermined rotational speed, and causes the model to change due to contact with the road surface. Deformation is calculated by numerical calculation.

In the next step ST102, the grouping process execution unit 11 selects two or more continuous groups that meet a predetermined connection condition for a plurality of surfaces that constitute the tire outer surface including the grooves 20 in the tire finite element method model M2. A grouping process is executed in which the faces to be processed are grouped as one group face.

In the next step ST103, the time-series data acquisition unit 13 obtains the first node P1 at the intersection of the outermost sides forming each group surface and the second node P1 forming each ungrouped surface. Time-series data on the displacement between P2 and at least a portion of the third nodes P3 among all the nodes forming the groove spatial element 30 is acquired from the deformation calculation results of the model M2.

In the next step ST104, the fluid calculation unit 14 uses a fluid analysis model in which the space around the tire including the tire outer surface and the road surface is represented by a plurality of computational grid cells C1, and uses the first node P1 and the second node P1 in the time-series data. Using the node P2 and the third node P3 as control points, a fluid analysis calculation is performed to calculate the physical quantity of the fluid for each computational grid cell C1 while changing the position of the computational grid cell C1.

As described above, the fluid analysis method around the tire according to the present embodiment is
A method, performed by one or more processors, comprising:
Under analysis conditions including a predetermined load, a predetermined internal pressure, and a predetermined rotational speed, a first model M2 representing a tire having grooves 20 formed on the contact surface with a plurality of elements and nodes is rolled, and the road surface and the model M2 are rolled. Calculating the deformation of the first model M2 caused by the contact by numerical calculation (ST101);
Two or more continuous surfaces (F01 to F04) meeting predetermined bonding conditions are grouped into a plurality of surfaces (F01 to F08) constituting the tire outer surface including the grooves 20 in the first model M2. Execution of grouping processing for surface G01 (ST102);
Time-series data on the displacement between the first node P1 at the intersection of the outermost sides forming each group surface G01 and the second node P2 forming each ungrouped surface (F05 to F08) from the deformation calculation result of the first model M2 (ST103);
Using a second model in which the space around the tire including the tire outer surface and the road surface is represented by a plurality of computational grid cells C1, the position of the computational grid cell C1 is determined using the first node P1 and the second node P2 in the time-series data as control points. (ST104);
including.

The fluid analysis system 1 around the tire of this embodiment includes:
Under analysis conditions including a predetermined load, a predetermined internal pressure, and a predetermined rotational speed, a first model M2 representing a tire having grooves 20 formed on the contact surface with a plurality of elements and nodes is rolled, and the road surface and the model M2 are rolled. a structural calculation unit 12 that numerically calculates the deformation of the first model M2 caused by the contact;
Two or more continuous surfaces (F01 to F04) meeting predetermined bonding conditions are grouped into a plurality of surfaces (F01 to F08) constituting the tire outer surface including the grooves 20 in the first model M2. a grouping process execution unit 11 that executes a grouping process for the surface G01;
Time-series data on the displacement between the first node P1 at the intersection of the outermost sides forming each group surface G01 and the second node P2 forming each ungrouped surface (F05 to F08) from the deformation calculation result of the first model M2;
Using a second model in which the space around the tire including the tire outer surface and the road surface is represented by a plurality of computational grid cells C1, the position of the computational grid cell C1 is determined using the first node P1 and the second node P2 in the time-series data as control points. A fluid calculation unit 14 that executes a fluid analysis calculation that calculates the physical quantity of the fluid for each computational grid cell C1 while changing
Prepare.

According to this configuration, two or more continuous faces that meet the predetermined joining condition are taken as one group face. Since the first node P1 at the intersection of the outermost sides of all the nodes forming the group surface is used as the control point, the number of control points is lower than when all the nodes forming the group surface are used as control points. The number can be reduced, the calculation cost of deformation processing of the computational grid cell C1 is reduced, and the calculation time can be shortened. Moreover, there are cases where it is possible to suppress deterioration of calculation accuracy or calculation failure by using a predetermined connection condition.

As in the present embodiment, each surface constituting the tire outer surface belongs to either the first surface group Gp1 or the second surface group Gp2, and the outer surface rotationally symmetric about the tire axis The outer surfaces that belong to the surface group Gp1 and are not rotationally symmetrical about the tire axis belong to the second surface group Gp2, and the grouping process is performed on the surfaces belonging to the first surface group Gp1 and the second surface group. It is preferably not performed for faces belonging to Gp2.

In this way, since the space formed by the surfaces belonging to the first surface group Gp1, which are arranged at rotationally symmetrical positions about the tire axis, changes little due to rotation, a calculation failure occurs even if the grouping process is executed. is less likely to occur, and the computational cost can be reduced. On the other hand, the space formed by the surfaces belonging to the second surface group Gp2, which are arranged at positions that are not rotationally symmetrical about the tire axis, change a lot due to rotation, and there is a risk that the grouping process may cause a calculation failure in the first surface group. higher than Gp1. However, since the grouping process is not executed for the faces belonging to the second face group Gp2, it is possible to prevent the occurrence of computational failure.

As in the present embodiment, it is preferable that the contact surface composed of the nodes that are candidates for contact with the road surface and the groove wall surface forming the groove 20 belong to the second surface group Gp2.

Since the grouping process is not executed for the grooves 20 and the treads that are likely to change due to the rotation of the tire, it is possible to suppress the occurrence of computational failure.

As in the present embodiment, the tire has a plurality of grooves 20, and the outer surface located radially outside RD1 of the imaginary line L1 connecting the bottoms of the plurality of grooves 20 may belong to the second surface group Gp2. preferable.

The outer surfaces located on the outer side RD1 in the tire radial direction from the imaginary line L1 connecting the bottoms of the plurality of grooves 20 are the tread portions that are likely to be deformed due to the rotation of the tire. , it becomes possible to suppress the occurrence of calculation failure.

As in the present embodiment, the outer surface of the member defined as the tread portion having the ground contact surface and the grooves 20 belongs to the second surface group Gp2 and is defined as the body portion located radially inward RD2 of the tread portion. The outer surface of the member preferably belongs to the first surface group Gp1.

Since the grouping process is not performed on the outer surface of the member defined as the tread portion having the ground contact surface, it is possible to suppress the occurrence of calculation failure. At the same time, the grouping process is performed on the outer surface of the member defined as the body portion located radially inward RD2 of the tire from the tread portion. Calculation cost can be reduced.

As in this embodiment, the predetermined bonding condition may include either that the adjacent surfaces are parallel or that the adjacent surfaces are within a predetermined angle with respect to parallelism. preferable.

According to this configuration, adjacent surfaces that are parallel or within a predetermined angle with respect to the parallel state are grouped. It is possible to reduce calculation costs while suppressing calculation errors.

As in the method of the present embodiment, the first model M2 has the groove space element 30 located in the groove space surrounded by the groove wall surface forming the groove 20, and obtaining the time series data is performed in the first Time-series data on the displacements of the first node P1, the second node P2, and at least a part of the third nodes P3 of all the nodes forming the groove space element 30 are acquired from the deformation calculation results of the first model M2. It is preferable to use the first node P1, the second node P2, and the third node P3 in the time-series data as control points for executing the fluid analysis calculation.
Like the system of this embodiment, the first model M2 has a groove space element 30 arranged in a groove space surrounded by groove wall surfaces forming the groove 20, and the time-series data acquisition unit 13 includes the first Obtaining time-series data on the displacement of the node P1, the second node P2, and at least a part of the third nodes P3 of all the nodes forming the groove space element 30 from the deformation calculation result of the first model M2, The fluid calculation unit 14 preferably uses the first node P1, the second node P2, and the third node P3 in the time-series data as control points.

According to this configuration, not only the first node P1 and the second node P2 that form the outer surface of the tire but also the second node P2 that forms the groove space element 30 are used as control points for the mesh morphing process that changes the position of the computational grid cell C1. Since the third node P3 is also used as a control point, even complicated groove deformation that deteriorates the quality of the computational grid with only the first node P1 and the second node P2 constituting the tire outer surface can be controlled. By increasing the number of points, it is possible to generate a good spatial interpolation field and prevent deterioration of the quality of the computational grid due to the mesh morphing process. Therefore, it becomes possible to suppress quality deterioration and calculation failure of the fluid analysis.

As in this embodiment, the Young's modulus of the groove spatial element 30 is set to 1/10000 or more and 1/1000 or less of the Young's modulus set to the element forming the ground contact surface, and the Poisson modulus of the groove spatial element 30 Preferably the ratio is set to 0±0.01.

If the groove space element 30 is set in this way, even if the groove is complicatedly deformed by contact with the road surface, the groove space element 30 can be deformed following the groove deformation without hindering the groove deformation. Therefore, the deformation of the tire can be calculated with high accuracy.

A program according to the present embodiment is a program that causes a computer to execute the above method.
By executing these programs as well, it is possible to obtain the effects of the above method.

Although the embodiments of the present disclosure have been described above based on the drawings, it should be considered that the specific configurations are not limited to these embodiments. The scope of the present disclosure is indicated not only by the description of the above embodiments but also by the scope of claims, and includes all modifications within the meaning and scope equivalent to the scope of claims.

It is possible to adopt the structure adopted in each of the above embodiments in any other embodiment. The specific configuration of each part is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present disclosure.

REFERENCE SIGNS LIST 11 grouping process execution unit 12 structure calculation unit 13 time series data acquisition unit 14 fluid calculation unit 20 groove 30 groove spatial element M2 tire finite element method model (first model)
C1 computational grid cell Gp1 first surface group Gp2 second surface group

Claims (17)

A method, performed by one or more processors, comprising:
Under analysis conditions including a predetermined load, a predetermined internal pressure, and a predetermined rotational speed, the first model, which expresses a tire having grooves formed on the contact surface with a plurality of elements and nodes, is rolled to prevent contact with the road surface. Calculating the deformation of the first model caused by numerical calculation;
performing a grouping process in which two or more continuous surfaces that meet a predetermined combination condition are grouped as one group surface for a plurality of surfaces that constitute the tire outer surface including the grooves in the first model; ,
Deformation of the first model with time-series data on displacement between a first node at the intersection of the outermost sides forming each of the group surfaces and a second node forming each ungrouped surface. obtaining from the result of the operation;
Using a second model in which the space around the tire including the outer surface of the tire and the road surface is represented by a plurality of computational grid cells, the positions of the computational grid cells with the first node and the second node in the time-series data as control points performing a fluid analysis calculation for calculating the physical quantity of the fluid for each computational grid cell while changing
Fluid analysis methods around tires, including Each surface constituting the tire outer surface belongs to either the first surface group or the second surface group,
The outer surface that is rotationally symmetrical about the tire axis belongs to the first surface group,
The outer surface that is not rotationally symmetrical about the tire axis belongs to the second surface group,
2. The method of claim 1, wherein the grouping process is performed for faces belonging to the first group of faces and not for faces belonging to the second group of faces. 3. The method according to claim 2, wherein a contact surface composed of nodes that are candidates for contact with the road surface and groove wall surfaces forming the groove belong to the second surface group. The tire has a plurality of grooves,
The method according to claim 2 or 3, wherein an outer surface located outside in the tire radial direction of an imaginary line connecting the bottoms of the plurality of grooves belongs to the second surface group. The outer surface of the member defined as the tread portion having the ground contact surface and the groove belongs to the second surface group,
The method according to any one of claims 2 to 4, wherein an outer surface of a member defined as a body portion located radially inward of the tread portion belongs to the first surface group. 6. Any one of claims 1 to 5, wherein the predetermined bonding condition includes either that surfaces adjacent to each other are parallel or that surfaces adjacent to each other are within a predetermined angle with respect to the state of parallelism. The method described in Crab. The first model has a groove space element arranged in a groove space surrounded by groove wall surfaces forming the groove,
Acquiring the time-series data includes time-series data relating to displacements of the first node, the second node, and at least a portion of the third nodes among all the nodes constituting the groove spatial element. Obtained from the deformation calculation result of the first model,
The method according to any one of claims 1 to 6, wherein executing the fluid analysis operation uses the first node, the second node and the third node in the time-series data as control points. The Young's modulus of the groove space element is set to 1/10000 or more and 1/1000 or less of the Young's modulus set to the element forming the ground contact surface, and the Poisson's ratio of the groove space element is 0±0. 8. The method of claim 7, set to 01. Under analysis conditions including a predetermined load, a predetermined internal pressure, and a predetermined rotational speed, the first model, which expresses a tire having grooves formed on the contact surface with a plurality of elements and nodes, is rolled to prevent contact with the road surface. a structural calculation unit that calculates the deformation of the first model caused by numerical calculation;
Grouping for performing a grouping process on a plurality of surfaces that constitute the tire outer surface including the grooves in the first model so that two or more continuous surfaces that meet a predetermined combination condition are grouped as one group surface. a processing execution unit;
Deformation of the first model with time-series data on displacement between a first node at the intersection of the outermost sides forming each of the group surfaces and a second node forming each ungrouped surface. a time-series data acquisition unit that acquires from the calculation result;
Using a second model in which the space around the tire including the outer surface of the tire and the road surface is represented by a plurality of computational grid cells, the positions of the computational grid cells with the first node and the second node in the time-series data as control points a fluid calculation unit that executes a fluid analysis calculation that calculates the physical quantity of the fluid for each computational grid cell while changing
A fluid analysis system around a tire, comprising: Each surface constituting the tire outer surface belongs to either the first surface group or the second surface group,
The outer surface that is rotationally symmetrical about the tire axis belongs to the first surface group,
The outer surface that is not rotationally symmetrical about the tire axis belongs to the second surface group,
10. The system of claim 9, wherein the grouping process is performed for faces belonging to the first group of faces and not for faces belonging to the second group of faces. 11. The system according to claim 10, wherein a contact surface composed of nodes that are candidates for contact with the road surface and groove wall surfaces forming the groove belong to the second surface group. The tire has a plurality of grooves,
The system according to claim 10 or 11, wherein an outer surface located outside in the tire radial direction of an imaginary line connecting the bottoms of the plurality of grooves belongs to the second surface group. The outer surface of the member defined as the tread portion having the ground contact surface and the groove belongs to the second surface group,
The system according to any one of claims 10 to 12, wherein an outer surface of a member defined as a body portion radially inward of the tread portion belongs to the first surface group. 14. Any one of claims 9 to 13, wherein the predetermined bonding condition includes either that the surfaces adjacent to each other are parallel or that the surfaces adjacent to each other are within a predetermined angle with respect to the state of parallelism. the system described in The first model has a groove space element arranged in a groove space surrounded by groove wall surfaces forming the groove,
The time-series data acquisition unit acquires time-series data on displacements of the first node, the second node, and at least a portion of the third nodes of all the nodes forming the groove spatial element. Obtained from the deformation calculation result of the model,
15. The system according to any one of claims 9 to 14, wherein said fluid calculation unit uses said first node, said second node and said third node in said time-series data as control points. The Young's modulus of the groove space element is set to 1/10000 or more and 1/1000 or less of the Young's modulus set to the element forming the ground contact surface, and the Poisson's ratio of the groove space element is 0±0. 16. The system of claim 15, set to 01. A program that causes one or more processors to execute the method according to any one of claims 1 to 8.

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