JP2013007709A - Tire performance simulation method, tire performance simulation device, and tire performance simulation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately simulate deformation of the surroundings of a tire cord.SOLUTION: A tire performance simulation method includes: a step 102 of creating a tire whole model obtained by performing element breakdown of the whole of a tire into a plurality of elements; a step 104 of creating a cord surrounding model obtained by performing the element breakdown including the tire cord and rubber in the surroundings of the tire cord by a plurality of solid elements for components including the tire cord among the components constituting the tire; a step 106 of executing a deformation calculation of the tire whole model; steps 108 and 110 of giving physical quantity at a position equivalent to the cord surrounding model of the tire whole model to the cord surrounding model as a boundary condition on the basis of a result of the deformation calculation of the tire whole model; and a step 112 of executing the deformation calculation of the cord surrounding model on the basis of the boundary condition.

Description

  The present invention relates to a tire performance simulation method, a tire performance simulation apparatus, and a tire performance simulation program. More specifically, the present invention relates to a tire performance simulation method and tire performance for analyzing tire performance by a numerical analysis method such as a finite element method. The present invention relates to a simulation apparatus and a tire performance simulation program.

  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 (for example, see Patent Document 1). 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.

  By the way, the tire is configured to include many tire cords as well as a rubber material. This tire cord is used by forming a plurality of cores (filaments) in a complex twisted manner. Thus, a technique for modeling a tire cord portion when a tire is simulated by FEM is known (see, for example, Patent Document 2).

JP 2006-293432 A JP 2009-196598 A

  However, the technique described in Patent Document 2 does not consider the influence of rubber around the tire cord when modeling the tire cord. In the tire model, the influence of each tire cord is not taken into consideration. For this reason, there has been a problem that rolling resistance due to deformation of rubber inside and around the tire cord and durability due to distortion at a ply end such as a belt or a sidewall cannot be accurately evaluated.

  The present invention has been made to solve the above problems, and provides a tire performance simulation method, a tire performance simulation device, and a tire performance simulation program capable of accurately simulating deformation around a tire cord. Objective.

  In order to achieve the above object, the tire performance simulation method according to the first aspect of the present invention includes a step of creating an entire tire model in which the entire tire is divided into a plurality of elements, and among the constituent members constituting the tire For a component including a tire cord, a step of creating a cord peripheral model in which the tire cord and rubber around the tire cord are divided into a plurality of solid elements, and a step of executing deformation calculation of the entire tire model A physical quantity at a position corresponding to the cord peripheral model of the tire overall model as a boundary condition based on the result of the deformation calculation of the tire overall model, based on the boundary condition Performing a deformation calculation of the code surrounding model. And features.

  According to the present invention, for the constituent members including the tire cord among the constituent members constituting the tire, a cord peripheral model is created by dividing the element with a plurality of solid elements including the tire cord and the rubber around the tire cord, Based on the result of the deformation calculation of the entire tire model, a physical quantity at a position corresponding to the code surrounding model of the entire tire model is assigned as a boundary condition to the code surrounding model, and the deformation calculation of the code surrounding model is performed based on this boundary condition. Execute. As a result, the deformation around the tire cord can be accurately simulated.

  In addition, as described in claim 2, the deformation calculation may be executed using a viscoelastic material as a rubber material constituting the entire tire model and the cord peripheral model.

  According to a third aspect of the present invention, in the deformation calculation of the cord periphery model, tire performance relating to rolling resistance of the tire may be calculated.

  According to a fourth aspect of the present invention, the tire performance relating to the rolling resistance may include at least one of shear strain and strain energy loss.

  According to a fifth aspect of the present invention, the physical quantity can be any one of displacement, speed, and acceleration.

  A tire performance simulation apparatus according to a sixth aspect of the present invention includes a tire overall model creating means for creating a tire overall model in which the entire tire is divided into a plurality of elements, and a tire code among the constituent members constituting the tire. A cord perimeter model creating means for creating a cord perimeter model that is divided into a plurality of solid elements including the tire cord and rubber around the tire cord, and a deformation calculation of the tire overall model. 1 execution means, and on the basis of the result of deformation calculation of the tire overall model, an assigning means for assigning a physical quantity at a position corresponding to the code surrounding model of the tire overall model as a boundary condition to the code surrounding model; A second execution for performing a deformation calculation of the code surrounding model based on the boundary condition; Characterized by comprising a stage, a.

  The tire performance simulation program of the invention according to claim 7 includes a step of creating a tire overall model in which the entire tire is divided into a plurality of elements, and a constituent member including a tire code among constituent members constituting the tire. A step of creating a cord peripheral model divided into a plurality of solid elements including the tire cord and the rubber surrounding the tire cord; a step of executing deformation calculation of the overall tire model; and a deformation of the overall tire model Based on the calculation result, a step of assigning a physical quantity at a position corresponding to the cord peripheral model of the overall tire model as a boundary condition to the cord peripheral model, and a deformation calculation of the code peripheral model based on the boundary condition And executing a process including: And characterized in that.

  The present invention has an effect that the deformation around the tire cord can be simulated with high accuracy.

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 perspective view showing an example of the whole tire model. (A) is a perspective view showing an example of a tire cord model, (B) is a perspective view showing an example of a cord peripheral model including a tire cord model and rubber around it. (A) is sectional drawing of the whole tire model, (B) is the partially expanded view of (A). It is a partially enlarged view of the vicinity of the belt of the overall tire model. It is a partially enlarged view of the vicinity of the belt of the overall tire model. It is sectional drawing of the whole tire model. It is a partial enlarged view of the whole tire model. It is a figure for demonstrating arrangement | positioning of a code periphery model. It is a figure which shows an example of the code | cord | chord surrounding 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 22 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 22, so that a tire performance simulation program, which will be described later, is recorded in the CD-ROM 22 in advance. The tire performance simulation program recorded on the CD-ROM 22 may be read and executed via the CD-ROM drive 22. 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 an MD or 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 for tire shape, structure, material, etc.) of multiple types of tires is stored in advance in the hard disk of the computer 12, and the design data of the tire to be subjected to behavior analysis is selected. Thus, it is possible to set a tire to be subjected to behavior analysis.

  In the next step 102, a tire overall model for the entire tire for creating a tire design plan into a numerical analysis model is created. The creation of the overall 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 entire 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 refers to dividing an object such as a tire and a road surface 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. FIG. 4 shows an example of the overall tire model 30.

  In the entire tire model, for example, rubber is defined by a solid element, and a reinforcing material such as a belt or a carcass is defined by a membrane element, a shell element, or a rebar element or a solid element corresponding thereto.

  In step 104, a cord perimeter model including a tire cord and surrounding rubber is created. In the code surrounding model, each element is defined by a solid element. FIG. 5A shows an example of a tire cord model 32 in which only a tire cord is modeled. FIG. 5B shows a cord circumference model 34 including the tire cord model 32 and rubber around the tire cord model 32. An example was given.

  In FIG. 5A, the tire cord model 32 is an example of a steel cord having three filaments 36 as an example, which are twisted in the same twist direction and filled with a filler between the filaments 36. It is a three-dimensional model.

  The cord surrounding model 34 is a model including a tire cord model 32 and a rubber model 38 that models the surrounding rubber. As shown in FIG. 5A, the tire cord model 32 is mesh-divided according to the twist of the filament 36, so that it is difficult to match the tire cord model 32 with the rubber model 38. For this reason, the rubber model 38 is divided into meshes independently of the tire cord model 32.

  Then, for each of the mesh nodes on the outer periphery of the tire code model 32, the nearest node is searched among the nodes of the inner mesh that come into contact with the tire code model 32 of the rubber model 38. The relative positional relationship between each of the mesh nodes on the outer circumference of the tire code model 32 and the nearest node searched for each of these nodes is not changed during the behavior analysis of the code surrounding model 34, that is, Each node is defined to be constrained.

  Instead of constraining the nodes, for each of the meshes on the outer periphery of the tire cord model 32, the nearest mesh is searched from the inner meshes contacting the tire cord model 32 of the rubber model 38, and the tire The relative positional relationship between each of the mesh nodes on the outer periphery of the code model 32 and the nearest mesh searched for each of these nodes is defined so as not to change during the behavior analysis of the code surrounding model 34. Also good.

  In step 106, behavior analysis of the entire tire model 30 is performed. Specifically, first, boundary conditions are set. The boundary conditions are necessary for the analysis of the tire overall model 30, that is, for simulating the behavior of the tire, and are various conditions given to the tire overall model 30. In setting the boundary conditions, for example, an internal pressure, a load load, or the like is applied to the entire tire model 30. Then, based on the boundary condition given to the entire tire model 30, the behavior on the tire contact surface is calculated by the finite element method. That is, the deformation calculation of the entire tire model 30 is performed based on the finite element method. In this deformation calculation, for example, a known rolling analysis method can be used for analysis. In rolling analysis, analysis with tire slip angle and camber angle set, analysis combined with vehicle model of vehicle to which tire is attached, and analysis combined with road surface model modeled by dividing road surface into elements be able to. In the road surface model, the road surface state can be set. For example, the road surface condition can be set by setting the friction coefficient μ of the road surface corresponding to drying (DRY), wetting (WET), on ice, on snow, non-paved, etc. as necessary.

  In step 108, based on the result of the deformation calculation of the entire tire model in step 106, the part to be analyzed in detail, for example, the reinforcing material such as a belt or a carcass including the tire cord in the entire tire model 30, and the periphery thereof The displacement of the part to be extracted is extracted.

  For example, as shown in FIG. 6A, a case where the displacement of a portion corresponding to the belt 40 of the tire is extracted will be described. In this case, as shown in FIG. 5B, in the overall tire model 30, the belt 40 is defined by a single membrane element.

  As shown in FIG. 7, the belt 40 actually has a thickness and includes a tire cord 44 and a rubber 46 around the tire cord 44. For this reason, in the example of FIG. 7, the displacement of each node of the mesh including the belt 40 is extracted.

  In step 110, the extracted displacement is given to the external boundary of the code surrounding model 34 created in step 104 as a forced displacement boundary condition. For example, when analyzing the end portion of the belt 40, as shown in FIG. 8, the displacement of the nodes 52 of the meshes 50A and 50B including the end portion of the belt 40 is represented by the outer boundary (in FIG. It is given to the node on the thick line part).

  At this time, since the positions of the nodes of the tire overall model 30 and the cord peripheral model 34 are different, for example, in the example of FIG. 8, based on the displacement of the nodes 52A to 52F of the meshes 50A and 50B including the ends of the belt 40. Then, the displacement applied to the outer boundary of the code surrounding model 34 is interpolated. As an interpolation method, for example, there are methods using linear interpolation, polynomial interpolation, and a shape function of a finite element method. For example, in the interpolation using the shape function of the finite element method, the displacement to be given to the outer boundary of the code surrounding model 34 is calculated according to the following equation.

Here, U _i (vector) is an interpolated displacement, that is, a displacement applied to the outer boundary of the code surrounding model 34. N _A is the shape function, U _A (vector) is the displacement of the nodes of the mesh of the overall tire model 34 including the outer boundary of the code surrounding model 34, and nn is the number of nodes of the mesh. For example, the displacement of the nodes on the outer boundary of the upper half of the code surrounding model 34 in FIG. 8 is based on the displacement of the nodes 52A to 52D of the mesh 50B of the tire overall model 30 including the nodes on the outer boundary (1 ) And the displacement of the node on the outer boundary of the lower half of the code surrounding model 34 is based on the displacement of the four nodes 52C to 52F of the mesh 50A of the entire tire model 30 including the node on the outer boundary. Then, it is obtained by the above equation (1).

  In step 112, the behavior analysis of the code surrounding model 34 is performed based on the finite element method based on the boundary condition given in step 110. That is, the deformation calculation of the code surrounding model 34 is performed. Specifically, for example, performance related to tire rolling resistance, for example, interlaminar shear strain and strain energy loss when the belt is formed in two layers.

  In step 114, the calculation result, for example, the shape of the code surrounding model 34 calculated in step 112 is output to the display 14 or the like. The carcass ply end region 54 shown in FIG. 9 can be analyzed in the same manner as described above.

  The rubber material for the entire tire model and the cord peripheral model may be defined by an elastic material, but is preferably defined by a viscoelastic material. By defining the viscoelastic material, the tire performance can be simulated more accurately.

  As described above, in this embodiment, deformation calculation is performed in consideration of the rubber around the tire cord, so that the deformation around the tire cord can be accurately simulated.

  In the present embodiment, a displacement is obtained as a physical quantity at a position corresponding to the cord peripheral model of the entire tire model based on the deformation calculation result of the entire tire model, and this is given as a boundary condition to the cord peripheral model. As described above, velocity or acceleration may be obtained as the physical quantity, and this may be given as a boundary condition to the code surrounding model.

  (Example)

  Next, examples of the present invention will be described.

  First, an overall tire model with a tire size of 195 / 65R15 was created. FIG. 9 shows a cross-sectional view of the created tire overall model 50.

  Then, a simulation was performed in which an internal pressure of 210 kPa and a load of 4.0 kN were applied to the entire tire model as boundary conditions, and rolling analysis was performed on a flat rigid road surface at a speed of 60 km / h. As shown in FIG. 10 in which the end region 52 of the belt in FIG. 9 is enlarged, the belt has a two-layer structure of belts 40A and 40B, and the tire radial direction and the circumference generated between the layers of the end portions of these two belts. The strain energy loss due to the shear strain in the direction and the total strain component was obtained. In addition, the generalized Maxwell model, which is a material model that takes viscoelasticity into consideration as a rubber material, was also used to determine the strain energy loss at the same position.

  The tire cord model 32 has a structure in which, for example, as shown in FIG. 11A, three filaments 60 having a diameter a of 0.25 mm are twisted, and the thickness b is 0 around the tire cord model 32. A cord peripheral model 34 having a length of 4 mm and a length c of one side of the cross section of 1.4 mm and a length of 1 mm in the longitudinal direction as a whole was prepared. Then, the intersection angle of the two belts 40A and 40B is set to 66 degrees, and the cord peripheral models 34A and 34B are arranged corresponding to this angle, and the entire tire is arranged on the outer boundary, that is, the outer surface of the cord peripheral models 34A and 34B. The displacement obtained by the interpolation method described above from the displacement time history of each node around the belt end of the model 50 was applied and analyzed.

  As shown in FIG. 11A, the cord perimeter model A in the following table includes a cord perimeter model 34A corresponding to the end of the belt 40A and a cord perimeter model 34B corresponding to the end of the belt 40B. The cord peripheral model B is a model that is arranged at the same position in the width direction in a direction orthogonal to the width direction of the tire, and the cord peripheral model B includes two parts corresponding to the end portions of the belt 40A as shown in FIG. This is a model in which the cord peripheral model 34A is arranged side by side along the width direction of the tire, and the cord peripheral model 34B corresponding to the end of the belt 40B is overlapped at the center.

  The analysis results of interlaminar shear strain and strain energy loss are shown below. Here, the strain energy loss is obtained by multiplying the stress and strain of each element by the material loss (tan δ) and the volume. In addition, the result which calculated | required the energy loss using the generalized Maxwell model which is a material model which considered the viscoelasticity for the rubber material was also shown. The analysis result in the overall tire model is set to 100.

上記の結果より、コード周囲モデルＡ、Ｂについては、タイヤ全体モデルより詳細にモデル化しているため、全ての歪が大きくなっていること、コード周囲モデルの配置の違いによって解析結果が異なることが判り、本発明のようにタイヤコードの周囲のゴムも考慮して解析することにより精度よくタイヤコード周辺の変形計算を精度よく行うことができることが判った。

From the above results, the cord perimeter models A and B are modeled in more detail than the overall tire model, so that all the distortions are large and the analysis results differ depending on the arrangement of the cord perimeter models. As can be seen, it was found that the deformation calculation around the tire cord can be accurately performed by analyzing the rubber around the tire cord as in the present invention.

  Next, a code surrounding model 70 as shown in FIG. 12 was created. The tire cord 72 had a diameter of 0.5 mm and a rubber having a circumference of 0.2 mm. In accordance with the radial ply direction, the displacement of the entire tire model 50 was analyzed on the outer surface of the cord peripheral model 70 as a boundary condition by applying the displacement obtained by interpolation using the shape function of the finite element method as described above. . As a result, we were able to analyze the distortion that occurred between the ply cords that could not be analyzed by the whole tire model.

10 Keyboard 12 Computer 14 Display 16 Mouse 18 Hard Disk 22 CD-ROM Drive

Claims (7)

Creating a whole tire model in which the whole tire is divided into a plurality of elements;
A step of creating a cord peripheral model obtained by dividing an element into a plurality of solid elements including a tire cord and rubber around the tire cord for a constituent member including a tire cord among the constituent members constituting the tire;
Performing deformation calculation of the entire tire model;
Based on the result of the deformation calculation of the entire tire model, a physical quantity at a position corresponding to the code surrounding model of the entire tire model is provided as a boundary condition to the code surrounding model;
Performing deformation calculation of the code perimeter model based on the boundary condition;
A tire performance simulation method including: The tire performance simulation method according to claim 1, wherein the deformation calculation is executed using a viscoelastic material as a rubber material constituting the entire tire model and the cord periphery model. The tire performance simulation method according to claim 1 or 2, wherein, in the deformation calculation of the cord periphery model, tire performance relating to rolling resistance of the tire is calculated. The tire performance simulation method according to claim 3, wherein the tire performance related to the rolling resistance includes at least one of shear strain and strain energy loss. The tire performance simulation method according to any one of claims 1 to 4, wherein the physical quantity is any one of displacement, speed, and acceleration. A tire whole model creating means for creating a tire whole model by dividing the whole tire into a plurality of elements;
Cord surrounding model creating means for creating a cord surrounding model obtained by dividing an element by a plurality of solid elements including the tire cord and rubber around the tire cord with respect to a constituent member including a tire cord among the constituent members constituting the tire When,
First execution means for executing deformation calculation of the entire tire model;
Based on the result of the deformation calculation of the entire tire model, an imparting unit that assigns a physical quantity at a position corresponding to the cord surrounding model of the entire tire model as a boundary condition to the cord surrounding model;
Second execution means for performing deformation calculation of the code surrounding model based on the boundary condition;
Tire performance simulation device equipped with. Creating a whole tire model in which the whole tire is divided into a plurality of elements;
A step of creating a cord peripheral model obtained by dividing an element into a plurality of solid elements including a tire cord and rubber around the tire cord for a constituent member including a tire cord among the constituent members constituting the tire;
Performing deformation calculation of the entire tire model;
Based on the result of the deformation calculation of the entire tire model, a physical quantity at a position corresponding to the code surrounding model of the entire tire model is provided as a boundary condition to the code surrounding model;
Performing deformation calculation of the code perimeter model based on the boundary condition;
Tire performance simulation program for causing a computer to execute processing including

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