JP4814751B2 - Tire model creation method, apparatus, and program - Google Patents

Description

  The present invention relates to a tire model creation method, apparatus, and program, and relates to a tire model creation method, apparatus, and program used when analyzing the performance of a pneumatic tire used in an automobile or the like.

  The analysis of tire behavior is based on the results of measuring the tires actually designed and manufactured and using the results of performance tests obtained by mounting them on automobiles. Can now be realized. As a main method for analyzing the tire behavior by simulation, a numerical analysis method such as a finite element method (FEM) is mainly used. FEM is a technique of modeling a structure with a finite number of elements and analyzing the behavior of the structure using a computer, and divides the structure into a finite number of elements from its features (hereinafter referred to as mesh division or Element division). In order to simulate tire behavior with high prediction accuracy, how to produce a tire model for simulation (consisting of numerical data) composed of a finite number of elements in the same way as the actual tire shape is important.

  Therefore, as a technique for simulating the behavior of the tire, a technique for modeling the tire and simulating it by a finite element method (FEM) is known (for example, see Patent Document 1).

The finite element method includes two methods, an implicit method (Implicit or Static analysis) suitable for static tire analysis and an explicit method (Explicit or Dynamic analysis) that can take into account dynamic components such as inertial force. Kinds of solutions are known. In particular, in a simulation in which a tire rolls at a speed of 100 km / h, if the influence of centrifugal force caused by rotation is neglected, the prediction accuracy by the simulation may be reduced. It is common to use a finite element method (hereinafter referred to as an explicit solution FEM). The explicit FEM is also used in the analysis of the tire stepping on the projection on the road surface and the analysis including the dynamic component such as traveling on the irregular road surface due to the characteristics of the dynamic analysis. As the explicit method FEM, for example, commercially available general-purpose software such as ABAQUS-Explicit, Pam-Crash, Dyna3D is known.
JP 2002-350294 A

  By the way, in designing the tire shape and structure, when simulating the tire performance such as the degree of deformation and internal stress while the tire is running by the finite element method (FEM), for example, the carcass line and the belt line have an internal pressure. The number and position of the grooves in the top tread has a significant effect on the shear force in the tread and the ground contact behavior during rolling. .

  However, in order to predict the performance of tires with different shapes and structures, tire models must be created one by one that match the shape and structure of each tire so that the tire performance can be faithfully simulated. It was. In particular, when a plurality of design factors are examined at the same time, the number of combinations is enormous, and the creation of a tire model requires an enormous amount of man-hours. For this reason, the calculation time tends to be long, and simulating the behavior of the tire such as predicting the tire performance results in high calculation cost (it takes calculation time).

  In view of the above facts, an object of the present invention is to obtain a tire model creation method, apparatus, and program capable of improving calculation efficiency in a tire analysis or the like by a numerical analysis method such as a finite element method.

  In order to achieve the above object, the invention described in claim 1 is a tire model creation method for calculating a tire corresponding to a numerical calculation model in order to simulate the behavior of the tire in a use state. A plurality of tire cross-sectional shapes each including a tire member of the same type and different cross-sectional shape are divided into elements, and each element corresponding to at least a part of each tire member divided into elements is formed as a candidate A tire cross-section basic model set for the member is created in advance and stored in the storage means, and at least one formation candidate member set in the tire cross-section basic model read from the storage means is designated, and the designated formation candidate is designated. The tire is determined by setting a material constant smaller than a predetermined material constant as a corresponding tire member for the designated formation candidate member so that no member exists. Fixed surface basic model of the tire cross-section modified model, characterized by creating a tire model based on the modified tire section modified model.

  In the present invention, in the storage means, a tire cross section in which a plurality of tire cross-sectional shapes are overlaid and each element corresponding to at least part of each tire member divided into the elements is set as a formation candidate member The basic model is stored. That is, each element corresponding to at least a part of the tire member is created and stored in advance as a mapping table corresponding to each tire member as a formation candidate member. When at least one of the formation candidate members is designated, a material constant smaller than a material constant predetermined as a tire member corresponding to the designated formation candidate member is determined so that the designated formation candidate member does not exist. The tire cross-section basic model in which the material constant is determined is corrected as a tire cross-section correction model. A tire model is created from the tire cross-section correction model. This means that the formation candidate member is designated to function as a dummy element that does not exist in the numerical calculation on the tire model, and a plurality of tire model shapes and structures can be created. That is, it is possible to create a plurality of tire models that can behave as if there are no elements by simply changing the material constant setting.

  The tire model includes a line representing the outer shape of the tire, a line representing the tire crown shape, a carcass line representing the carcass of the tire, a belt line representing the belt inside the tire, and a folded ply representing the folded line of the carcass ply inside the tire. There are reinforcing material lines representing lines and various reinforcing material lines, and grooves such as rib grooves and sipes are included. In the tire model, a position for identifying these is determined. Specifically, the angle distribution of the belt layer representing the gauge distribution of the tire rubber member and the structure of the belt portion, the width, the cord type, the driving density, and the pattern shape representing the block shape, block groove wall angle, sipe position, The number and length can be included.

  Therefore, the carcass line described in claim 2, the belt line described only in claim 3, and the tire rubber member such as the rib groove described in claim 4 can be adopted as the tire member. By setting these tire members, when obtaining tire models corresponding to different tire shapes and structures, it is as if at least a part of the tire members does not exist just by changing the material constant setting. It is possible to freely create a plurality of tire models that can be allowed to act.

  Further, as described in claim 5, as the material constant, a constant defining at least one element deformation behavior of an elastic coefficient, a viscosity coefficient, and a Poisson's ratio can be adopted. Only by setting a constant that defines the behavior at the time of element deformation, elements that do not contribute to element deformation can be determined, and a plurality of tire models can be easily created.

  By using the model, the behavior of the tire with high accuracy can be simulated in a short time, and a tire model creation device can also be provided. Specifically, as described in claim 6, in order to simulate the behavior of the tire in a use state, the tire model creation device calculates the tire corresponding to the numerical calculation model, and the same A plurality of tire cross-sectional shapes each including tire members having different cross-sectional shapes are divided into elements, and each element corresponding to at least a part of each of the tire members divided into elements is defined as a formation candidate member. A storage means for storing the set tire cross-section basic model; a specifying means for specifying at least one formation candidate member set in the tire cross-section basic model read from the storage means; and the specified formation candidate member does not exist The tire cross-section basic model is determined by setting a material constant smaller than a predetermined material constant as a corresponding tire member for the designated formation candidate member. And correction means for correcting the tire section modified model, characterized by comprising a generating means for generating a tire model based on the modified tire section modified model.

  Further, when analyzing the behavior of the tire by a computer, it is possible to reduce the calculation load and perform numerical calculation by using the model. In the tire model, as described in claim 7, in order to simulate the behavior of the tire in use, the computer for calculating the tire corresponding to the numerical calculation model has the same type and different cross-sectional shapes. The tire cross-section base is divided into elements in a state where a plurality of tire cross-sectional shapes each including the tire members are overlapped, and each element corresponding to at least a part of each of the divided tire members is set as a formation candidate member Storage means for storing the model, specification means for specifying at least one of the formation candidate members set in the tire cross-section basic model read from the storage means, and designation so that the designated formation candidate member does not exist The tire cross-section basic model is typed by setting a material constant smaller than a predetermined material constant as a corresponding tire member for the formed candidate member. And correction means for correcting the cross-section modified model, the tire model creation program to function as a creating means for creating a tire model based on the modified tire section modified model can be easily provided.

  As described above, according to the present invention, a tire model is defined in a state where a plurality of tire cross-sectional shapes are overlapped, and a material constant is determined so that a formation candidate member set to the tire model does not exist as a tire member. As a result, it is possible to provide a plurality of tire models that can behave as if there are no elements there, and to achieve efficient tire development.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, the present invention is applied to the creation of a tire model used for tire behavior analysis.

(Device configuration)
FIG. 1 shows an outline of a personal computer for carrying out the tire model creation method of the present invention. This personal computer includes a keyboard 10 for inputting data and the like, a computer main body 12 for creating a tire model in accordance with a pre-stored processing program for creating a tire model, and a CRT 14 for displaying calculation results of the computer main body 12 and the like. It is configured. The computer main body 12 includes a mass storage device 16 such as a hard disk device for storing the processing program and the like. The processing program includes an analysis program such as a tire behavior simulation, and the performance of the tire can be predicted using the computer main body 12.

  The computer main body 12 includes a flexible disk unit (FDU) into which a flexible disk (FD) as a recording medium can be inserted and removed. Note that processing routines and the like described later can be read from and written to the flexible disk FD using the FDU. Therefore, a processing routine to be described later may be recorded in the FD in advance and the processing program recorded in the FD may be executed via the FDU. Further, the processing program recorded in the FD may be stored (installed) in the mass storage device 16 and executed. As the recording medium, there are optical disks such as CD-ROM and DVD, and magneto-optical disks such as MD and MO. When these are used, a corresponding device may be used instead of or in addition to the FDU. Of course, a workstation or a supercomputer may be used in addition to the personal computer.

(Tire section basic model)
In the present embodiment, in order to perform an analysis such as a tire behavior simulation using a numerical calculation model, a tire model is created as the numerical calculation model. In creating the tire model, one tire cross-section basic model including dummy elements capable of easily creating a plurality of tire models having different shapes and structures is created in advance and stored in the mass storage device 16. Yes. Using this one tire cross-section basic model, by selecting use / unnecessity of dummy elements, a tire model to be analyzed such as a tire behavior simulation is created.

  FIG. 2 shows a processing routine of a creation program for creating a tire cross-section basic model. FIG. 3 shows a processing routine of a creation program for creating various tire models using one created tire cross-section basic model.

  When power is turned on to the computer main body 12 and a tire model creation in the computer main body 12 is instructed by a predetermined operation with the keyboard 10, the processing routine of FIG. Data is read. The tire cross-section data includes data determined from a tire design plan (tire shape, structure, material, etc.) and data obtained by measuring an existing tire.

  FIG. 4 shows an example of a tire cross section, and shows a pneumatic tire 20 having a carcass 22 divided for each of a plurality of rubber members. The carcass 22 is folded back by a bead 26. The inner side of the carcass 22 is an inner liner 24, and a bead rubber 36 is disposed on the inner liner 24 so as to extend. A substantially triangular area formed by the folded carcass 22 is a bead filler 28. A belt 30 is disposed above the carcass 22, a tread rubber 32 in which grooves 38 such as rib grooves are formed is disposed on the outer side in the radial direction of the belt 30, and a side rubber is disposed on the outer side in the axial direction of the carcass 22. 34 is arranged. These carcass 22, inner liner 24, bead 26, bead filler 28, belt 30, tread rubber 32, side rubber 34, bead rubber 36, and groove 38 are tire members. In addition, although the example which divided | segmented the tire cross-section model into plurality for every rubber member was given, you may divide | segment into arbitrary shapes, such as a triangle.

  Next, in step 202 of FIG. 2, tire members are classified for each tire, and in the next step 204, formation candidate regions for tire members classified for each tire are extracted. These processes are to classify data such as the carcass 22, the belt 30, and the groove 38 that are tire members, and to set an area that each tire member occupies in the tire 20 as a formation candidate area and extract the data.

  FIG. 5 shows a part of the tire 20 having belts 30A and 30B having different belt widths as an example of a tire member. The tire 20 shown in FIG. 5A and the tire 20 shown in FIG. 5B are the same except for the belt width where the belt 30A and the belt 30B are different. In the example of FIG. 5, an area occupied by the belt 30 </ b> A and the belt 30 </ b> B, which are one of the belts as tire members, is set as a formation candidate area, and the data is extracted.

  Next, in step 206 in FIG. 2, tire members having a common part are classified as similar members for the same type of tire member among a plurality of tires, and each tire member can be expressed for a plurality of similar members. One integrated member is set (classified). In the next step 208, an identifier is given to the common part and the different part of each tire member in the integrated member, and in the next step 210, the tire member (single member) and the integrated member of the single part without having the common part. A material number (identification number) is assigned to each of them for identification with the others. As an example of the material number, in the case of a belt, it can be abbreviated as BL1, BL2,.

  FIG. 6 is an explanatory diagram for setting an integrated member from the belt 30 including the belts 30A and 30B having different belt widths shown in FIG. 5 as an example of the tire member. When the belt 30 is a belt 30A, 30B, 30C, 30D having different belt widths among the tire members for a plurality of tires, the belt 30A is common and the belts 30B, 30C, 30D are only extended in that order. . For this reason, all the belt widths can be specified only by setting the distance according to the difference from the common part of the belt width to the longest part.

  Therefore, in Step 206, the belts 30A, 30B, 30C, and 30D having different belt widths are classified as similar members. In step 208, identifiers A, B, C, and D are given to the common part and the different part of the belt 30. The different parts of the belts 30B and 30C can be collectively set as the identifier E, and the different parts of the belts 30B, 30C and 30D can be set as the identifier F together.

  Table 1 below shows the relationship between tire members, material numbers, and identifiers as a table.

  In Table 1 above, an example of the belt is shown as the tire material, the integrated member is shown as material number BL1, and the single member is shown as material number BL2. In the case of this single material, an identifier is not required, but a predetermined identifier such as an identifier Z may be defined as a specified value.

  When the identifier and the material number are assigned as described above, element division is performed in step 212 of FIG. In this embodiment, a case where a finite element method (FEM) such as an explicit method is used as a numerical analysis method will be described. Element division is to divide an object such as a tire into several small (finite) small parts, calculate for each small part, calculate all the small parts, and then add all the small parts. The overall response can be obtained. Accordingly, in step 212, input to a computer program created by dividing the tire section into a plurality of elements by element division corresponding to the finite element method (FEM), for example, mesh division, and based on a numerical / analytical method. Refers to digitization in data format.

  In the next step 214, a mapping table that represents the relationship between the tire member, the identifier, and the element after the element division is created for each tire member, and in the next step 216, structural data of the tire cross-section basic model is created as modeling. And stored with the mapping table. In the structure data of the tire cross-section basic model, all tire members are set as formation candidate areas, and further, the integrated member is set so as to be designated as formation candidate areas in detail. FIG. 7 shows an image of a tire cross-section basic model including a formation candidate region by tire members obtained from a plurality of tires created as described above. This tire cross-section basic model includes all tire members as formation candidate regions, and includes dummy elements (elements of formation candidate regions) that can easily create a plurality of tire models having different shapes and structures. .

  The tire cross-section basic model data composed of the tire cross-section basic model structure data and the mapping table is created in advance by the computer main body 12 or another computer and stored in advance in the mass storage device 16 in the computer main body 12. You may make it keep.

  Table 2 below shows the relationship between tire members, material numbers, identifiers, and elements as the correspondence relationship stored as the mapping table.

  In Table 2 above, the symbol q is used to indicate the position of the element after element division. An example of a belt is shown as a tire material, an integrated member is shown as a material number BL1, and a single member is shown as a material number BL2. In the case of this single material, an identifier is not required, but a predetermined identifier such as an identifier Z may be defined as a specified value.

(Tire model)
When the creation of the tire cross-section basic model is completed as described above and the tire cross-section basic model data including the structure data of the tire cross-section basic model and the mapping table is stored in the mass storage device 16, FIG. A tire model can be created according to the processing routine.

  In step 220 of FIG. 3, the above-described tire cross-section basic model data is read from the mass storage device 16. In the next step 222, tire members constituting the tire model created as the analysis model are set. This setting is made by reading the input value of the keyboard 10 and setting that the material number of the tire member made by the input of the keyboard 10 by the user and the identifier constituting the tire member of the material number are designated. Made.

  In this step 222, in response to the fact that at least a part of the tire members other than the tire members constituting the tire model is designated, a tire model for creating at least a part of the undesignated tire member as an analysis model is created. The tire member to be configured is set. That is, at least a part of formation candidate members unnecessary for the tire model to be created is designated.

  In the next step 224, a predetermined material constant is set for at least a part of the formation candidate members set in step 222. These material constants are all constants that define the deformation behavior of elements, such as various elastic coefficients, viscosity coefficients, Poisson's ratio, and the like. As the value, a minute value that does not appear as a behavior when the tire material is deformed is adopted. Specifically, a standard value of tire material or a value of 1/1000 or 1/10000 of the reference value can be adopted. Also, a minute predetermined value such as 0.001 or 0.0001 may be used simply. Here, the case where all constants are set to the above minute values will be described, but only the dominant constants of the deformation behavior of elements may be used. In step 224 above, regular material constants of other tire members may be further determined.

  In the next step 226, a tire radial section model (tire section model, that is, tire section data) is created. In the tire cross-section data created in step 226, there is no change in the numerical calculation shape of the tire cross-section basic model created as a numerical calculation model, and only the material constants of at least some of the set formation candidate members are changed. It has been done. Accordingly, the processing in step 226 corresponds to defining a tire cross-section model, that is, tire cross-section data, in which only the material constant is changed with respect to the tire cross-section basic model.

  In step 226, rubber in the tire cross section, supplementary teaching materials (belts, plies, etc., reinforcing cords made of iron / organic fibers, etc., bundled in a sheet shape) are respectively used according to the modeling method of the finite element method. Model. In this case, it is desirable to model the rubber portion with an 8-node solid element and the reinforcing material with an anisotropic shell element capable of expressing an angle. For example, the rubber part can be handled by an eight-node solid element, and the reinforcing material (belt, ply) can be handled in a two-dimensional manner as the shell element by considering the angle θ of the reinforcing material.

  8 to 10 are explanatory diagrams for explaining that tire members constituting a tire model to be created as an analysis model are set, and that a plurality of tire cross-section models are created from the tire cross-section basic model by the setting. Indicated.

  FIG. 8 shows a tire cross section around the carcass 22. As shown in FIG. 8A, the tire cross-section basic model has five carcass lines KL1, KL2, KL3, KL4 as formation candidate members. Includes KL5. Among these carcass lines, at least part (or all) of formation candidate members unnecessary for the tire model to be created are designated, and correspondingly, at least part of unspecified carcass lines (Or all) is set to the carcass line constituting the tire model created as the analysis model.

  In the example shown in FIG. 8B, when a carcass line other than the carcass lines KL2 and KL4 is designated, the carcass lines KL2 and KL4 are set as carcass lines constituting the tire model. Similarly, in the example shown in FIG. 8C, the carcass lines KL1 and KL2 are set by specifying a carcass line other than the carcass lines KL1 and KL2, and in the example shown in FIG. 8D, other than the carcass lines KL2 and KL3. The carcass lines KL2 and KL3 are set by specifying the carcass lines.

  8B to 8D, a carcass designated as an unnecessary formation candidate member is shown in order to show a model that can behave as if the carcass line element does not exist there by the above designation. The line is not shown.

  FIG. 9 shows a tire cross section around the belt 30. As shown in FIG. 9A, the tire cross section basic model includes three belt lines BL1, BL2, and BL3 as formation candidate members. Yes. The belt line BL3 is an integrated member and is a belt line including identifiers A, B, and C. In the figure, identifiers are shown in parentheses. Among these belt lines, at least a part (or all) of formation candidate members unnecessary for the tire model to be created are designated, and correspondingly, at least a part of the belt lines not designated (Or all) is set as a belt line constituting a tire model created as an analysis model.

  In the example shown in FIG. 9B, a belt line other than the belt lines BL1 and BL3 (identifiers A and C) is designated, and the belt lines BL1 and BL3 (identifiers A and C) constitute a tire model. Set to line. Similarly, in the example shown in FIG. 9C, the belt lines BL1 and BL2 are set by specifying a belt line other than the belt lines BL1 and BL2, and in the example shown in FIG. Belt lines BL1, BL2, and BL3 (identifiers A and B) are set by specifying a belt line other than BL3 (identifiers A and B).

  In FIGS. 9B to 9D, a belt designated as an unnecessary formation candidate member is shown in order to show a model that can behave as if the element of the belt line does not exist there by the above designation. The line is not shown.

  FIG. 10 shows a tire cross section around the tread rubber 32. As shown in FIG. 10 (A), the tire cross section basic model has four grooves MZ1, MZ2, MZ3, and MZ4 as formation candidate members. Contains. In the figure, it is shown that the groove is composed of a plurality of elements, and each groove is indicated by hatching. Among these grooves, at least a part (or all) of formation candidate members unnecessary for the tire model to be created from now on are designated, and correspondingly, at least a part of the undesignated grooves (or All) are set in the grooves constituting the tire model created as the analysis model. A formation candidate member that is not designated as a groove is set as a rubber member as a part of the tread rubber 32.

  In the example shown in FIG. 10B, the grooves MZ2 and MZ4 are set as the grooves constituting the tire model by specifying a groove other than the grooves MZ2 and MZ4, and the other is a rubber as a part of the tread rubber 32. Set to member. Similarly, in the example shown in FIG. 10C, the grooves MZ1 and MZ3 are set by specifying a groove other than the grooves MZ1 and MZ3, and the other is set as a part of the tread rubber 32 to the rubber member.

  In FIGS. 10B and 10C, the line segment of the designated groove is not shown in order to show a model that can be made to behave so that the groove is present there by the above designation.

  FIG. 11 shows a tire cross-section model before and after designating elements (formation candidate members). FIG. 11A is an example of a tire cross-section basic model created by the process of FIG. 2, and FIG. 11B is a process up to step 226 of FIG. It is an example of a tire cross-section model that can be swung so that it does not exist (as it exists in the case of a groove).

  Using the tire cross-sectional model (tire radial cross-section model) after the definition as described above, in step 228 of FIG. 3, the tire cross-sectional data (tire radial cross-section model) that is two-dimensional data is used. Is developed in one circumferential direction (360 degrees) to create a three-dimensional (3D) model of the tire. FIG. 12 shows the process of creating a tire model. (A) is a tire cross-sectional model similar to FIG. 11 (B), (B) is an image diagram of the tire cross-sectional model being developed in the circumferential direction, and (C) is a round. 3 shows a three-dimensional (3D) model of a tire developed in minutes (360 degrees). In FIG. 12, a portion of the tire in the circumferential direction is finely divided, but it is needless to say that 360 degrees may be equally divided.

  As described above, in the present embodiment, when modeling a tire, a plurality of lines and elements are created in advance in a tire model cross section as a base, and the material constant of each element is changed to change the existence. Control presence or absence. In other words, the tire model is created only once for the tire cross-section basic model (or the tire model of the tire cross-section basic model), and by changing the input value at the time of FEM calculation created from the tire model, a plurality of shapes and structures can be obtained. This can greatly reduce the man-hours for creating the tire model.

(Behavior simulation)
FIG. 13 shows a processing routine of an analysis program for analyzing the behavior of the tire using the tire model described above.

  First, in step 100, data of a tire cross-section basic model that is created as described above (FIG. 2) and can represent a tire to be subjected to behavior analysis is read from the mass storage device 16. In the next step 102, a tire model for dropping the tire cross-section basic model into the numerical analysis model is created as described above (FIG. 3).

  After the tire model is created as described above, the process proceeds to step 104, where the road surface setting, that is, the road surface model is created and the road surface state is input. In this step 104, the road surface is modeled and input for setting the modeled road surface to an actual road surface state. The road surface is modeled by dividing the road surface shape into elements and selecting the road surface friction coefficient μ and inputting the road surface state. For example, depending on the road surface condition, there is a road friction coefficient μ corresponding to dry (DRY), wet (WET), on ice, snow, unpaved, etc., so by selecting an appropriate value for the friction coefficient μ, The road surface condition can be reproduced.

  A fluid model may be created and provided between the road surface and the tire model. The fluid model divides and models a part (or all) of a tire, a ground contact surface, and a fluid region including a region where the tire moves and deforms.

  In this way, when the road surface condition is input, the boundary condition is set in the next step 106. The boundary conditions are necessary for analysis of the tire model, that is, for simulating the behavior of the tire, and are various conditions given to the tire model. In setting the boundary condition in step 106, first, an internal pressure is applied to the tire model, and at least one of rotational displacement and straight displacement (displacement may be force or speed) and a predetermined load load are applied to the tire model. give. In addition, when considering friction with the road surface, only one of rotational displacement (or force or speed) or straight displacement (or force or speed) may be used.

  Next, a deformation calculation of the tire model as an analysis is performed based on the numerical model created or set up to step 106. That is, when the setting of the boundary condition is completed in step 106, the process proceeds to step 108, and the tire model is calculated for deformation. In this step 108, deformation calculation of the tire model is performed based on the finite element method from the tire model and the given boundary conditions. This deformation calculation repeats the tire model deformation calculation (for example, repeat the calculation within 1 msec) in order to obtain the tire rolling state (to obtain a transient state), and each time the boundary condition May be updated. The deformation calculation can employ a predetermined calculation time assuming that the tire deformation is in a steady state. In the next step 110, the calculation result is output. This calculation result uses a physical quantity at the time of tire deformation. Specifically, side deflection amount, contact shape, contact pressure distribution, lateral force acting on the tire center, and the like.

  The calculation result may be output by visualizing the value or distribution of the shape of the contact portion of the tire, the distribution of contact pressure, the force acting on the center of the tire, or the like. These can be derived from the calculation result value, amount of change or rate of change, force direction (vector), and distribution, and if they are displayed together with the tire model and pattern periphery in a diagram, etc., they are presented for easy understanding. Possible visualizations can be made.

  As described above, in the present embodiment, when a tire is modeled, elements are not added or deleted, but a plurality of elements are included in the tire model in advance as formation candidates (dummy elements). The presence or absence is controlled by changing the material constant of each element. In other words, a single tire cross-section basic model (or a tire model of the tire cross-section basic model) is created only once, and a plurality of shapes and structures are expressed by changing input values at the time of FEM calculation for the tire model. Can do. Therefore, compared to creating and calculating individual tire models, it is possible to create a tire model only by changing the material constants of the elements, and simulating the behavior of the tire by changing part of the structure When the analysis is performed as described above, the calculation cost can be reduced, that is, the calculation time can be shortened while maintaining the calculation accuracy without reducing the prediction accuracy.

  In the above, a single tire is used as an analysis target. However, the present invention is not limited to this, and an assembly model in which a tire and a rim are combined may be used as an analysis target. In this case, when considering using the tire in combination with various rims (wheels), the analysis may be performed by replacing the rim and the tire as a single structure (assembled model) with the tire (tire model).

  Moreover, you may employ | adopt the vehicle model which attached the tire as an analysis object. In this case, it is only necessary to add a vehicle model creation process by an existing method and perform a running simulation calculation.

  Next, embodiments of the present invention will be described in detail.

  The tire modeled as this example is an automobile tire having a tire size of PSR275 / 70R16, and a tire model was created when the structure of each of the carcass, belt, and groove was changed, and the time required for simulation was verified. . The results are shown in Table 3.

  As can be seen from Table 3, the time required for model creation and the calculation time are indicated by an index with each time required by the conventional method being 100. When each item is combined, the effect is even greater. Thus, according to this embodiment, it can be understood that it greatly contributes to shortening of the calculation time.

It is the schematic of the personal computer for enforcing the preparation method of the tire model concerning embodiment of this invention. It is a flowchart which shows the flow of the tire cross-section basic model creation process concerning embodiment of this invention. It is a flowchart which shows the flow of the tire model creation process concerning embodiment of this invention. It is a diagram which shows a tire cross-section model. FIG. 4 shows a part of a tire having belts having different belt widths, (A) is a belt having a short width, and (B) is an image diagram showing a belt having a long width. It is explanatory drawing of setting an integrated member from the belt of a different belt width. It is an image figure of a tire section basic model including a formation candidate field by a tire member obtained from a plurality of tires. The tire cross section around the carcass is shown, (A) is a basic tire cross section model, (B) is a carcass line KL2, KL4, (C) is a carcass line KL1, KL2, and (D) is a carcass line KL2, KL3. It is a conceptual diagram which shows a cross-sectional model. The tire cross section around the belt is shown, (A) is a tire cross section basic model, (B) is a belt line BL1, BL3, (C) is a belt line BL1, BL2, (D) is a belt line BL1, BL2, BL3. It is a conceptual diagram which shows the comprised tire cross-section model. FIG. 4 is a tire cross-sectional basic model, (B) is a groove cross section MZ2 and MZ4, and (C) is a conceptual view showing a tire cross section model composed of grooves MZ1 and MZ3. The tire cross-section model before and after designation | designated of an element (formation candidate member) is shown, (A) is a tire cross-section basic model before designation | designated, (B) is a conceptual diagram which shows the tire cross-section model after designation | designated. The tire model creation process is shown, (A) is a tire cross-sectional model, (B) is an image diagram during development, and (C) is a three-dimensional (3D) model. It is a flowchart which shows the flow of a process of the tire behavior analysis program.

Explanation of symbols

10 Keyboard 12 Computer body 14 CRT
16 Mass storage device 20 Pneumatic tire 30 Belt 32 Tread rubber FD Flexible disk (recording medium)

Claims (7)

In order to simulate the behavior of the tire in use, a tire model creation method for calculating a tire corresponding to a numerical calculation model,
A plurality of tire cross-sectional shapes each including a tire member having the same type and different cross-sectional shape are divided into elements, and each element corresponding to at least a part of each of the tire members divided is formed as a candidate member The tire cross-section basic model set to is created in advance and stored in the storage means,
Specify at least one formation candidate member set in the tire cross-section basic model read from the storage means,
The tire formation basic model is corrected to a tire cross-section correction model by setting a material constant smaller than a predetermined material constant as a corresponding tire member for the designated formation candidate member so that the designated formation candidate member does not exist,
A tire model creation method comprising creating a tire model based on a modified tire cross-section correction model. The method of creating a tire model according to claim 1, wherein the tire member is a carcass line. The tire model according to claim 1, wherein the tire member is a belt line. The method for creating a tire model according to claim 1, wherein the tire member is a rib groove. The tire material creation method according to claim 1, wherein the material constant is a constant that defines a behavior during deformation of at least one element of an elastic coefficient, a viscosity coefficient, and a Poisson's ratio. In order to simulate the behavior of the tire in use, a tire model creation device that calculates a tire corresponding to a numerical calculation model,
A plurality of tire cross-sectional shapes each including a tire member having the same type and different cross-sectional shape are divided into elements, and each element corresponding to at least a part of each of the tire members divided is formed as a candidate member Storage means for storing the tire cross-section basic model set in
Designation means for designating at least one of the formation candidate members set in the tire cross-section basic model read from the storage means;
A modification in which the tire section basic model is corrected to a tire section correction model by setting a material constant smaller than a predetermined material constant as a corresponding tire member for the designated formation candidate member so that the designated formation candidate member does not exist. Means,
A tire model creating apparatus, comprising: means for creating a tire model based on a modified tire cross-section corrected model. In order to simulate the behavior of the tire in use, a computer that calculates the tire corresponding to the numerical calculation model,
A plurality of tire cross-sectional shapes each including a tire member having the same type and different cross-sectional shape are divided into elements, and each element corresponding to at least a part of each of the tire members divided is formed as a candidate member Storage means for storing the tire cross-section basic model set in
Designation means for designating at least one of the formation candidate members set in the tire cross-section basic model read from the storage means;
A modification in which the tire section basic model is corrected to a tire section correction model by setting a material constant smaller than a predetermined material constant as a corresponding tire member for the designated formation candidate member so that the designated formation candidate member does not exist. Means,
A tire model creation program that functions as a creation means for creating a tire model based on a corrected tire cross-section correction model.

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