JP2012056393A - Tire model creation method, tire model creation apparatus, and tire model creation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire model creation method, tire model creation apparatus and tire model creation program that can accurately simulate tire performance while shortening an analysis time.SOLUTION: The tire model creation method includes: a step 112 of meshing an inner liner and a reinforcement material composing a tire into membrane elements; a step 114 of meshing composing members of the tire other than the inner liner and reinforcement material into solid elements; and a step 116 of defining rigidity or the like of each element.

Description

  The present invention relates to a tire model creation method, a tire model creation device, and a tire model creation program. More specifically, the present invention relates to a tire model creation method, a tire model creation device, and a tire model for analyzing tire performance by a finite element method. Regarding creation program.

  Conventionally, attempts have been made to reduce prototype costs and gain a deeper physical understanding by predicting various tire performances by numerical analysis such as the finite element method. Various techniques have been proposed with regard to a tire model creation method for this purpose (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-153520

  However, the above-described prior art has a problem that the analysis time is increased because the tire performance is simulated by creating a tire model by dividing each part of the tire into elements by solid elements.

  For example, in order to accurately calculate the eigenvalue of a high vibration frequency of about 2 kHz, it is necessary to make the element division fine. However, as the tire model is subdivided, the analysis time increases in a quadratic curve.

  The present invention has been made to solve the above-described problem. A tire model creation method, a tire model creation device, and a tire model creation program capable of accurately simulating tire performance while reducing analysis time The purpose is to provide.

  In order to achieve the above object, a tire model creation method according to the first aspect of the present invention includes a step of dividing an inner liner and a reinforcing material constituting a tire by a membrane element, and the steps other than the inner liner and the reinforcing material. And dividing the tire component into solid elements.

  The tire model creation device according to the second aspect of the present invention includes a first element dividing unit that divides an inner liner and a reinforcing material constituting the tire into elements by a membrane element, and a configuration of the tire other than the inner liner and the reinforcing material. And a second element dividing means for dividing the member into solid elements.

  According to a third aspect of the present invention, there is provided a tire model creation program comprising the steps of dividing an inner liner and a reinforcing material constituting a tire into elements by a membrane element, and constituting members of the tire other than the inner liner and the reinforcing material as solid elements. And a step of dividing the element.

  According to these inventions, since the inner liner is divided into elements by the membrane elements, it is possible to accurately simulate the tire performance while reducing the analysis time.

  According to the present invention, the tire performance can be accurately simulated while shortening the analysis time.

It is the schematic of the personal computer for implementing performance prediction of a tire. It is a schematic block diagram of a computer. It is a flowchart of a tire performance simulation program. It is a flowchart of tire model creation. It is sectional drawing of a tire. It is sectional drawing of a tire model.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an outline of a personal computer as a tire performance simulation apparatus for creating a tire model of a pneumatic tire and performing performance prediction as an example. This personal computer includes a keyboard 10 for inputting data, a computer 12 for creating a three-dimensional tire model and predicting performance according to a pre-stored processing program, calculation results and various screens by the computer 12, and the like. A display 14 to be displayed and a mouse 16 for performing an operation of moving a cursor displayed on the display 14 to a desired position, selecting, deselecting, or dragging a menu item or an object at the cursor position. It is configured to include.

  As shown in FIG. 2, the computer 12 includes a CPU (Central Processing Unit) 12A, a ROM (Read Only Memory) 12B, a RAM (Random Access Memory) 12C, a non-volatile memory 12D, and an input / output interface (I / O) 12E. Are connected to each other via a bus 12F.

  Connected to the I / O 12E are a keyboard 10, a display 14, a mouse 16, a hard disk 18, and a CD-ROM drive 21 into which a CD-ROM 20 as a recording medium can be inserted and removed.

  The hard disk 18 stores a tire performance simulation program, which will be described later, and various parameters and data necessary for the execution thereof. The CPU 12A reads and executes a tire performance simulation program stored in the hard disk 18.

  Note that a tire performance simulation program, which will be described later, can be read from and written to the CD-ROM 20 using, for example, the CD-ROM drive 21, so that a tire performance simulation program, which will be described later, is recorded in the CD-ROM 20 in advance. The tire performance simulation program recorded on the CD-ROM 20 may be read and executed via the CD-ROM drive 21. Further, the recording medium is not limited to the CD-ROM, but includes an optical disk such as a DVD-ROM and a magneto-optical disk such as MD and MO. A DVD-ROM drive, MD drive, MO drive or the like may be used.

  Next, as a function of the present embodiment, a processing routine of a tire performance simulation program executed by the computer 12 will be described with reference to a flowchart shown in FIG.

  First, in step 100, a design plan (tire shape, structure, material, etc.) of a tire to be subjected to behavior analysis is determined. For example, design data such as CAD data (design data of tire shape, structure, material, etc.) of a plurality of types of tires is stored in the hard disk 18 in advance, and the design data of a tire to be subjected to behavior analysis is selected. By reading, it is possible to set a tire to be subjected to behavior analysis.

  Note that the setting in step 100 is not limited to the tire design plan, but includes the case of analyzing an existing tire. That is, the existing tire itself may be set as the target model.

  In the next step 102, a tire tire model for creating a tire design plan into a numerical analysis model is created. The creation of the tire model differs slightly depending on the numerical analysis method used. In this embodiment, a finite element method (FEM) is used as a numerical analysis method.

  Therefore, the tire model created in step 102 is divided into a plurality of elements by element division corresponding to the finite element method (FEM), for example, mesh division, and the tire is created based on a numerical / analytical method. This is a digitized input data format for computer programs. This element division means dividing an object such as a tire and a road surface (described later) into several small (finite) small parts, that is, elements. After calculating each element and calculating all the elements, the whole response can be obtained by adding all the elements.

  In the creation of the tire model in step 102, a tire model creation routine shown in FIG. 4 is executed.

  FIG. 5 shows an example of a tire cross section of a passenger car tire as an example. The tire 20 has a carcass 22 serving as a tire skeleton. 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 having a groove is disposed on the outer side in the radial direction of the belt 30, and a side rubber 34 is disposed on the outer side in the axial direction of the tire of the carcass 22. is doing. In the present embodiment, the belt 30 includes two belts 30A and 30B.

  In order to create a tire model for performing such tire performance analysis, first, in step 112, the inner liner 24 is divided into elements by membrane elements. Here, the membrane element is an element in which a force acts only in the surface direction. The membrane element can be defined by, for example, a triangle or a quadrilateral.

  Since the inner liner 24 has a relatively low rigidity, even if the element is divided by the membrane element having no bending rigidity, the influence on the accuracy of the simulation calculation of the tire performance is relatively small. Moreover, even if it is a membrane element, while maintaining mass and tensile rigidity, it is possible to calculate a stress and distortion, and it is useful for evaluation of the simulation result of a tire performance. For this reason, it is not preferable to omit the modeling.

  Therefore, in this embodiment, the inner liner 24 is divided into elements by membrane elements. Thereby, it is possible to accurately simulate the tire performance while shortening the analysis time.

  In step 114, other parts such as the carcass 22, the bead filler 28, the carcass 22, the belt 30, the tread rubber 32, the side rubber 34, and the bead rubber 36 are divided into elements. For example, the reinforcing material such as the belt 30 and the carcass 22 is defined by membrane elements, and the other tread rubber 32 and the like are divided into elements by solid elements.

  Here, the solid element is an element defined by a solid having a thickness, and can be defined by a tetrahedron, a pentahedron, a hexahedron, or the like.

  In step 116, rigidity characteristics and the like are defined for each element obtained by dividing the element, and this routine is terminated.

  In this way, a tire model of the tire 20 is created. FIG. 6 shows an example of a cross-sectional view of the created tire model.

  After the tire model including the finite element model (analysis model) of the tire 20 created as described above is created, the process proceeds to step 104 in FIG. 3 where road surface setting, that is, creation of the road surface model and input of the road surface state are made. The 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. Next, a rotational displacement and a straight displacement (displacement may be force or speed), a predetermined load load, or the like is applied to the tire model according to desired calculation conditions.

  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. In this deformation calculation, a known rolling analysis method can be used.

  In the next step 110, the calculation result is output. This calculation result uses a physical quantity at the time of tire deformation. Specifically, the amount of side deflection, contact shape, contact pressure distribution, lateral force acting on the center of the tire, moment, eccentric eigenvalue in the vertical direction of the tire, 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 or rate of change, force direction (vector), and distribution, and can be presented in an easy-to-understand manner by representing them with a diagram etc. along with the tire model and pattern periphery. Visualization is possible.

  Thus, in this embodiment, the inner liner 24 is divided into elements by the membrane elements. Thereby, it is possible to accurately simulate the tire performance while shortening the analysis time.

  (Example)

  Next, examples of the present invention will be described. Table 1 below shows the calculation of the eccentric eigenvalue in the vertical direction of the tire in the conventional method, that is, in the case where the inner liner is modeled with a solid element, and the method of the present invention, that is, the inner liner as a membrane element. The simulation results of analysis time and vibration frequency in the case of using a modeled tire model and in the case of the modeled tire model are shown. The numerical values in the table are normalized with the result of the conventional method as 100.

As shown in Table 1 above, it was found that the analysis time can be shortened as compared with the conventional method when a simulation is performed with a tire model in which the inner liner is modeled with a membrane element as in the present invention.

10 Keyboard 12 Computer 14 Display 16 Mouse 18 Hard Disk 20 Tire 21 CD-ROM Drive 22 Carcass 24 Inner Liner 26 Bead 28 Bead Filler 30 Belt 32 Tread Rubber 34 Side Rubber 36 Bead Rubber

Claims (3)

Dividing the inner liner and the reinforcing material constituting the tire into membrane elements, and
Dividing the components of the tire other than the inner liner and the reinforcing material into solid elements, and
Tire model creation method including. First element dividing means for dividing the inner liner and the reinforcing material constituting the tire into elements by membrane elements;
Second element dividing means for dividing the constituent members of the tire other than the inner liner and the reinforcing material into elements by solid elements;
Tire model creation device including Dividing the inner liner and the reinforcing material constituting the tire into membrane elements, and
Dividing the components of the tire other than the inner liner and the reinforcing material into solid elements, and
Tire model creation program for causing a computer to execute processing including