JP2013049383A - Simulation method and simulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simulation method and a simulation device capable of highly accurately performing a tire behavior analysis using a numeric value analysis technique such as a finite element method (FEM).SOLUTION: This simulation method uses a tire model generated by dividing a tire into a finite number of elements, in the tire having at least one of a skeleton member or a reinforcing member formed by coating an organic fiber cord with coating rubber. The simulation method includes a process A of generating the tire model, and the process A includes a process A1 of defining the skeleton member or the reinforcing member as any element of a film element or a shell element or a solid element, and a process A2 of inputting a Young's modulus of the organic fiber cord as a physical property value used for calculating tensile strain and inputting a Young's modulus of the coating rubber as a physical property value used for calculating compressive stain, to the element.

Description

  The present invention relates to a tire simulation method and a simulation apparatus.

  Conventionally, tire behavior was analyzed by measuring tires that were actually designed and manufactured, using performance test results obtained by mounting tires that were actually designed and manufactured on automobiles, and so on.

  However, in recent years, with the development of the computer (computer device) environment, it has become possible to realize the analysis of the behavior of the tire by simulation on the computer.

  As a method for analyzing tire behavior by simulation, a numerical analysis method such as a finite element method (FEM) is mainly known.

  FEM is a technique for analyzing the behavior of a target structure using a model generated by dividing the target structure into a finite number of elements on a computer device. The target structure is divided into a finite number of elements. (That is, performing mesh division or element division on the target structure) is necessary.

  In order to simulate the behavior of a tire with high accuracy, a tire model (consisting of numerical data) generated by dividing the tire into a finite number of elements is generated in the same way as the actual tire shape. It is important to do.

  Here, when generating a tire model using a numerical analysis method such as the finite element method, the skeleton member and the reinforcing member of the tire such as a ply and a belt are set to the physical property values (rigidity and anisotropy) of the member. There is known a method of defining as an element such as a membrane element, a shell element, or a solid element having the following (for example, Chapter 9 of Reference 1).

  The membrane element or the shell element is defined by a line in the two-dimensional model (2D model), and is defined by a plane in the three-dimensional model (3D model). The solid element is defined by a plane in the two-dimensional model (2D model), and is defined by a polyhedron in the three-dimensional model (3D model).

Composite material engineering, edited by Hayashi Hayashi, Nikka Giren Publisher, 1971, ISBN 4-8171-9008-6

Japanese Patent No. 4559694 JP 2003-94916 A JP 2008-08822 A

  By the way, in the simulation method according to the prior art, when generating a tire model, a skeleton member such as a ply or a belt or a reinforcing member is defined as an element, and a physical property value corresponding to the member is set for the element. However, at this time, when the skeleton member or the reinforcing member has an organic fiber cord, a method of setting a Young's modulus corresponding to the rigidity of the organic fiber cord is general.

  Specifically, the rigidity of the organic fiber cord provided in the skeleton member or the reinforcing member is sufficiently higher than the rigidity of a surrounding rubber member such as a coating rubber. Therefore, in the prior art, the same Young's modulus corresponding to the stiffness of the organic fiber cord is set for both the physical property value used for calculating the tensile strain and the physical property value used for calculating the compressive strain, and a model (so-called It is common to generate an elastic material model.

  Here, since the organic fiber cord is formed by twisting thin strands of fibers, when the compressive strain is generated in the skeleton member or the reinforcing member having the organic fiber cord, the strands forming the organic fiber cord become bent. . Therefore, in practice, the Young's modulus when compressive strain occurs in the skeleton member or the reinforcing member having the organic fiber cord is not as high as the Young's modulus when tensile strain occurs.

  However, in the prior art, since the same Young's modulus is set for the physical property value used for calculating the compressive strain and the physical property value used for calculating the tensile strain, the bending stiffness that greatly affects the compressive strain is calculated. At that time, the calculation result was different from the actual value.

  In particular, when analyzing the tire behavior when the tire is in contact with the road surface, the bending deformation amount of the tire side portion where the tensile strain and the compressive strain are generated largely deviates between the calculation result and the actual value. As a result, there is a problem that the prediction accuracy such as the contact pressure distribution with the road surface and the contact area is significantly lowered.

  Therefore, the present invention has been made in view of the above-described problems, and a simulation method capable of highly accurately analyzing the behavior of a tire using a numerical analysis method such as a finite element method (FEM) and the like. An object is to provide a simulation apparatus.

  The first feature of the present invention is that a skeleton member (carcass ply layer 30) formed by coating an organic fiber cord with a coating rubber, or a reinforcing member (belt reinforcing layer 10, In a tire including at least one of the inclined belt layers 20A and 20B), a simulation method using a tire model generated by dividing the tire into a finite number of elements, the tire model A step A1 for defining at least one of the skeletal member or the reinforcing member as a membrane element, a shell element, or a solid element; and In addition, the Young's modulus of the organic fiber cord is input as the physical property value used for calculating the tensile strain, and the compression strain is calculated. As physical property values used in the, and summarized in that comprising the step A2 to enter the Young's modulus of the coating rubber.

  Another feature of the present invention is that the ratio E2 / E1 between the Young's modulus E2 of the coating rubber and the Young's modulus E1 of the organic fiber cord is in the range of 0 <E2 / E1 <0.008. To do.

  Another feature of the present invention is that, in the step A1, the inclined belt layer of the tire, which is the reinforcing member, is defined as any element of a membrane element, a shell element, or a solid element.

  Another feature of the present invention is that, in the step A1, the belt reinforcing layer of the tire, which is the reinforcing member, is defined as any element of a membrane element, a shell element, or a solid element.

  Another feature of the present invention is that, in the step A1, the carcass ply layer of the tire, which is the skeleton member, is defined as any element of a membrane element, a shell element, or a solid element.

  The gist of the second feature of the present invention is that it is a simulation apparatus for executing the simulation method according to the above-described feature of the present invention.

  As described above, according to the present invention, it is possible to provide a simulation method and a simulation apparatus capable of performing a tire behavior analysis using a numerical analysis method such as a finite element method (FEM) with high accuracy. Can do.

FIG. 1 is a flowchart showing a simulation method according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating an example of an analysis target tire used in the simulation method according to the first embodiment of the present invention. FIG. 3 is a perspective view showing an example of an analysis target tire used in the simulation method according to the first embodiment of the present invention. FIG. 4 is a graph illustrating the relationship between strain and Young's modulus used in the simulation method according to the prior art. FIG. 5A is a graph illustrating the relationship between strain and Young's modulus used in the simulation method according to the first embodiment of the present invention. FIG. 5B is a graph illustrating the relationship between strain and stress used in the simulation method according to the first embodiment of the present invention. FIG. 6 is a schematic diagram of a computer apparatus for executing the simulation method according to the first embodiment of the present invention. FIG. 7A is a graph illustrating the relationship between strain and Young's modulus used in the simulation method according to the modified example of the present invention. FIG. 7B is a graph illustrating the relationship between strain and Young's modulus used in the simulation method according to the modification of the present invention. FIG. 8A is a graph illustrating the relationship between strain and stress used in the simulation method according to the modified example of the present invention. FIG. 8B is a graph illustrating the relationship between strain and stress used in the simulation method according to the modified example of the present invention. FIG. 9 is a diagram for explaining a comparative evaluation test performed using the conventional example and Examples 1 to 3. FIG. 10 is a diagram for explaining a comparative evaluation test performed using the conventional example and Examples 1 to 3.

(Simulation method according to the first embodiment of the present invention)
A simulation method according to the first embodiment of the present invention will be described with reference to FIGS. Specifically, the simulation method according to the present embodiment analyzes the behavior and performance of a tire (for example, a pneumatic tire) used in an automobile or the like using a finite element method. FIG. 1 shows a flowchart of a simulation method according to the first embodiment of the present invention.

  As shown in FIG. 1, in step S101, design information (for example, tire shape, structure, material, etc.) of the tire 1 to be analyzed is input. Here, the analysis target tire 1 may be a newly designed tire 1 or an existing tire 1.

  2 shows a cross-sectional view in the tread width direction (X-axis direction) of the tire 1 to be analyzed, and FIG. 3 shows a perspective view of the tire 1 to be analyzed.

  As shown in FIG. 2, the tire 1 to be analyzed includes a carcass ply layer 30, two inclined belt layers 20 </ b> A and 20 </ b> B provided outside the carcass ply layer 30 in the tire radial direction (Z-axis direction), It is assumed that a belt reinforcing layer (so-called spiral belt layer) 10 provided on the outer side in the tire radial direction of the inclined belt layers 20A and 20B is provided.

  The inclined belt layers 20A and 20B are belt layers in which a plurality of cords arranged at the same inclination angle with respect to the tire equatorial plane are crossed between the layers, and the belt reinforcing layer 10 is formed with respect to the tire equatorial plane. 1 belt layer disposed in the circumferential direction at an angle of approximately 0 degrees.

  Here, in the present embodiment, the belt reinforcing layer 10 and the inclined belt layers 20A and 20B constitute a reinforcing member of the tire 1 to be analyzed. In addition, a reinforcement member is not limited to this, A tire side part reinforcement layer, a bead part reinforcement layer (not shown), etc. may be contained and it is good also as one of these. Further, the carcass ply layer 30 constitutes a skeleton member of the tire 1 to be analyzed.

  In the present embodiment, the reinforcing member and the skeleton member are formed by coating an organic fiber cord with a coating rubber. Specifically, each of the belt reinforcing layer 10, the inclined belt layers 20A and 20B, and the carcass ply layer 30 is formed by coating an organic fiber cord with a coating rubber. Note that at least one of the reinforcing member and the skeleton member may be formed by coating an organic fiber cord with a coating rubber. Specifically, one of the belt reinforcing layer 10, the inclined belt layers 20A and 20B, and the carcass ply layer 30 may be formed by coating an organic fiber cord with a coating rubber, or a plurality of organic fiber cords may be formed. You may make it coat | cover with coating rubber.

  In the belt reinforcing layer 10, the inclined belt layers 20A and 20B, and the carcass ply layer 30, the organic fiber cord is formed by twisting elementary fibers using nylon, polyester, aramid, or the like as a material. The coating rubber can also hold the twisted organic fiber cord by coating the organic fiber cord, and can improve the adhesion of the organic fiber cord to tread rubber and the like, and is also called a corded rubber.

  In step S102, a tire model including a finite number of elements is generated by performing element division corresponding to the finite element method (that is, mesh division) on the tire 1 to be analyzed.

  Such a tire model is digitized into a format that can be handled by a computer device.

  Here, when generating the tire model described above (that is, when dividing the mesh), the skeleton member or the reinforcing member of the tire 1 to be analyzed is defined as any element of a membrane element, a shell element, or a solid element. .

  For example, as shown in FIG. 2, the belt reinforcing layer 10 and the inclined belt layers 20A and 20B, which are the reinforcing members of the tire 1 to be analyzed, are defined as either a membrane element, a shell element, or a solid element. Further, the carcass ply layer 30 which is a skeleton member of the tire 1 to be analyzed is also defined as any element of a membrane element, a shell element, or a solid element.

  Subsequently, for the element defined as the reinforcing member, the Young's modulus of the organic fiber cord is input as the physical property value used for calculating the tensile strain, and the Young's modulus of the coating rubber is used as the physical property value used for calculating the compressive strain. Enter the rate.

  Similarly, for the element defined as a skeleton member, the Young's modulus of the organic fiber cord is input as the physical property value used for calculating the tensile strain, and the Young's modulus of the coating rubber is used as the physical property value used for calculating the compressive strain. Enter the rate.

  In the present embodiment, both the reinforcing member and the skeleton member have a configuration in which an organic fiber cord is coated with a coating rubber. Therefore, in this embodiment, the case where the Young's modulus of the organic fiber cord and the Young's modulus of the coating rubber are input to both the element defined as the reinforcing member and the element defined as the skeleton member will be described as an example. To do. Note that the Young's modulus of the organic fiber cord and the Young's modulus of the coating rubber may be input only to at least one of the reinforcing member and the skeleton member.

  Here, FIG. 4 shows the relationship between the strain ε and the Young's modulus E used in the simulation method according to the prior art. FIG. 5 shows the relationship between strain ε and Young's modulus E used in the simulation method according to this embodiment. 4 to 5, in a region where the strain ε is a positive value (hereinafter referred to as a tensile strain region as appropriate), the relationship between the tensile strain ε and the Young's modulus is shown, and a region where the strain ε is a negative value (hereinafter referred to as a tensile strain region). , Which is appropriately shown as a compressive strain region) shows the relationship between the compressive strain ε and Young's modulus.

  As shown in FIG. 4, in the simulation method according to the prior art, the physical property value used when calculating the tensile strain and the compressive strain are calculated for the elements defined as the skeleton member and the reinforcing member. The same Young's modulus E1 was input as the physical property value.

  In the simulation method according to the present embodiment, as shown in FIG. 5A, the physical property values used for calculating the tensile strain and the tensile strain are calculated for the elements defined as the skeleton member and the reinforcing member. Different Young's moduli E1 to E2 are input as physical property values. The Young's modulus E1 and Young's modulus E2 satisfy the relationship E1> E2.

  Specifically, Young's modulus E1 input as a physical property value used for calculation of tensile strain is the Young's modulus of the organic fiber cord. On the other hand, the Young's modulus E2 input as a physical property value used for calculation of compressive strain is the Young's modulus of the coating rubber.

  FIG. 5B shows the relationship between the strain ε and the stress σ used in the simulation method according to this embodiment. As shown in the figure, when the strain ε is a positive value, that is, in the tensile strain region, the relationship of Young's modulus E1 = σ / ε is satisfied. On the other hand, when the strain ε is a negative value, that is, in the compression strain region, the relationship of Young's modulus E2 = σ / ε is satisfied.

  In the simulation method according to the present embodiment, the Young's modulus E1 of the organic fiber cord included in the belt reinforcing layer 10 is input as a physical property value used for calculating the tensile strain of the belt reinforcing layer 10 that is the reinforcing member of the tire 1 to be analyzed. To do. On the other hand, the Young's modulus E2 of the coating rubber included in the belt reinforcing layer 10 is input as a physical property value used for calculating the compressive strain of the belt reinforcing layer 10.

  Further, the Young's modulus E1 of the organic fiber cord included in the inclined belt layers 20A and 20B is input as a physical property value used for calculation of the tensile strain of the inclined belt layers 20A and 20B that are the reinforcing members of the tire 1 to be analyzed. On the other hand, the Young's modulus E2 of the coating rubber included in the inclined belt layers 20A and 20B is input as a physical property value used for calculating the compressive strain of the inclined belt layers 20A and 20B.

  Further, the Young's modulus E1 of the organic fiber cord included in the carcass ply layer 30 is input as a physical property value used for calculation of the tensile strain of the carcass ply layer 30 that is a skeleton member of the tire 1 to be analyzed. On the other hand, the Young's modulus E2 of the coating rubber included in the carcass ply layer 30 is input as a physical property value used for calculating the compressive strain of the carcass ply layer 30.

  In the present embodiment, the Young's modulus E2 of the coating rubber input to each of the belt reinforcing layer 10, the inclined belt layers 20A and 20B, and the carcass ply layer 30 is set to the same value, and the organic fiber cord The Young's modulus E1 is also set to the same value. The ratio E2 / E1 between the Young's modulus E2 of the coating rubber and the Young's modulus E1 of the organic fiber cord used in the embodiment of the present invention is preferably in the range of 0 <E2 / E1 <0.008. , E2 is considerably smaller than E1. The upper limit value 0.008 is a value obtained from a ratio of nylon-based organic fiber, which is a class having the smallest Young's modulus among organic fibers generally used for tires, and its coating rubber. The lower limit value 0 is 0 when the ratio of the aromatic polyamide, glass fiber, carbon fiber, etc., which is the class having the highest Young's modulus among the organic fibers used in the tire, and the coating rubber thereof is obtained. Therefore, this value was set as the lower limit value.

  Further, as shown in FIG. 2, the tire model (cross-sectional model) generated as a two-dimensional model is expanded 360 degrees into an annular shape, and a three-dimensional model tire model as shown in FIG. 3 is generated.

  In step S103, a road surface is set. That is, a road surface model is generated and a road surface state is input. For example, as the road surface state, a friction coefficient corresponding to dry (DRY), wet (WET), ice, snow, non-paving, or the like is input.

  In step S104, boundary conditions are set. Such boundary conditions are necessary when analyzing a tire model, and are various conditions given to the tire model. For example, the internal pressure, vertical load, rotational displacement (speed, force, etc.), straight displacement (speed, force, etc.), etc. to be applied to the tire model are set as boundary conditions.

  In step S105, a predetermined calculation is performed using the numerical model set in steps S101 to S104 described above, and the behavior and performance of the tire 1 to be analyzed are analyzed.

  As shown in FIG. 6, the simulation apparatus that executes the simulation method according to the present embodiment may be implemented by a computer apparatus or may be implemented by a software module that is executed by a processor of the computer apparatus. However, it may be implemented by a combination of both.

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

(Action and effect)
The following describes the operation and effects of the first embodiment of the present invention.

  Here, in a tire, in a skeleton member or a reinforcing member formed by coating an organic fiber cord with a coating rubber, when compressive strain occurs, the elementary fibers forming the organic fiber cord bend. Therefore, in reality, the rigidity of the skeleton member and the reinforcing member is comparable to the rigidity of the coating rubber formed around the organic fiber cord when compressive strain occurs.

  In the simulation method according to the present embodiment, a skeleton member formed by coating an organic fiber cord with a coating rubber and a reinforcing member formed by covering the organic fiber cord with a coating rubber are defined as elements, and the defined elements are Then, the Young's modulus E1 of the organic fiber cord is input as a physical property value used for calculating the tensile strain, and the Young's modulus E2 of the coating rubber is input as the physical property value used for calculating the compressive strain.

  Therefore, in the simulation method according to the present embodiment, compared to the case where the Young's modulus E1 used for calculating the tensile strain and the Young's modulus E1 used for calculating the compressive strain are the same as in the conventional technique, It is possible to generate a tire model having elements defined in accordance with a more actual situation.

  That is, in the simulation method according to the present embodiment, it is possible to predict tire performance such as tire behavior using a tire model having elements defined in accordance with a more actual situation.

  Thus, according to the simulation method according to the present embodiment, it is possible to analyze the tire behavior using a numerical analysis method such as a finite element method (FEM) with high accuracy.

(Modification 1)
Next, a description will be given first modification of the first embodiment described above.

  Here, in practice, the skeleton member and the reinforcing member formed by coating the organic fiber cord with the coating rubber are the change amount of the stress σ corresponding to the change of the strain ε in the boundary region between the tensile strain region and the compressive strain region. Gradually changes.

  In the simulation method according to this modified example, the Young's modulus E of the skeleton member and the reinforcing member is input in consideration of a gradual change in the amount of change in the stress σ corresponding to the change in the strain ε in the boundary region.

  FIG. 7A shows the relationship between the strain ε and the Young's modulus E according to this modification. As shown in the figure, in the boundary region between tensile strain and compressive strain (region from ε1 to ε2), Young's modulus E is preferably input based on a function indicating a change between stress σ and strain ε. .

  Further, the function indicating the Young's modulus E in the boundary region is not limited to a straight line, and a curve (for example, a quadratic curve, a three-time local line, or an exponential curve) may be used as shown in FIG. The function may be an approximate function calculated from actual measurement values.

  According to the simulation method according to this modified example, the Young's modulus E can be input in accordance with the actual situation in the boundary region between the tensile strain region and the compression strain region, so that a more accurate tire model can be generated. Thus, it is possible to predict tire performance such as tire behavior.

(Modification 2)
It will now be described a second modification of the first embodiment described above.

  Here, in an actual tire, it may be considered that the skeleton member and the reinforcing member formed by coating the organic fiber cord with the coating rubber are subjected to initial strain or initial stress.

  In the simulation method according to this modification, the Young's modulus E considering the initial strain or initial stress is input.

  FIG. 8A shows the relationship between the strain ε and the stress σ when the skeleton member and the reinforcing member are subjected to the initial strain ε0. FIG. 8B shows the relationship between the strain ε and the stress σ when the skeleton member and the reinforcing member are subjected to the initial stress σ0.

  According to the simulation method according to this modified example, as shown in FIGS. 8A to 8B, a tire model with higher accuracy can be obtained by inputting the Young's modulus E considering the initial strain ε0 and the initial stress σ0. Can be used to predict tire performance such as tire behavior.

(Comparison evaluation)
Next, in order to further clarify the effects of the present invention, a comparative evaluation test performed using the simulation method according to the conventional example and the simulation methods according to Examples 1 to 3 will be described. In addition, this invention is not limited at all by these examples.

  In this test, an internal pressure of 210 kPa is applied to a tire for a passenger car having a tire size of “195 / 65R15”, a vertical load of 4 kPa is applied at a camber angle of 0 ° and a slip angle of 0 °, and the coefficient of friction with the road surface is set to “1”. 0.0 ”, and the contact pressure distribution on the tire contact surface in the state of performing the pseudo rolling rotation analysis at a speed of 50 km / h, the measurement result in the actual tire, and the simulation according to the conventional example and Examples 1 to 3 The calculation results using the method were compared.

As shown in FIG. 9 and FIG. 10, the calculation results are obtained by comparing the ground pressure measured in an actual tire with the ground pressure calculated using the simulation method according to the conventional example and Examples 1 to 3. The deviation (position difference) at the position was defined as “ΔPi”, and “ΔPi ² ” integrated over the entire ground contact area was defined as “ΣΔPi ² ”.

Here, “ΣΔPi ² ” is an index indicating a difference from the contact pressure measured in the actual tire (an index indicating a deviation from the contact pressure measured in the actual tire), and the smaller the value, the higher the calculation accuracy. Is a good one. In Table 1, which will be described later, “ΣΔPi ² ” in the simulation method according to the conventional example is set as a reference “100” and compared by an index.

  In all the simulation methods, the tire 1 to be analyzed includes a single carcass ply layer 30 and two inclined belt layers 20A provided on the outer layer side of the carcass ply layer 30 as shown in FIG. And 20B, and one belt reinforcing layer 10 provided on the outer layer side of the inclined belt layers 20A and 20B.

  In the analysis target tire 1, the carcass ply layer 30, the inclined belt layers 20A and 20B, and the belt reinforcing layer 10 are formed by coating an organic fiber cord with a coating rubber. In all the simulation methods, a three-dimensional model is used as a tire model.

  In all the simulation methods, the carcass ply layer 30 is defined as a single film element, the two inclined belt layers 20A and 20B are defined as two film elements, and the belt reinforcing layer 10 is defined as a single film film. Defined as an element (or shell element).

  In the simulation method according to the conventional example, when the tire model is generated, the physical property value (hereinafter, the physical property value in the tensile strain region) used for calculating the tensile strain and the compressive strain are calculated for each membrane element. The Young's modulus E1 of the organic fiber cord was input as a physical property value (hereinafter, a physical property value in the compression strain region). That is, a model (so-called elastic material model) in which the same Young's modulus E1 is input to the Young's modulus for calculating the tensile strain and the Young's modulus for calculating the compressive strain was generated.

  On the other hand, in the simulation method according to the first embodiment, when generating the tire model, the physical property values and compression in the tensile strain region are applied to the respective membrane elements of the inclined belt layers 20A and 20B and the belt reinforcing layer 10. The Young's modulus E1 of the organic fiber cord was input as the physical property value of the strain region. In the simulation method according to Example 1, the Young's modulus E1 of the organic fiber cord is input as the physical property value of the tensile strain region for the film element of the carcass ply layer 30, and the coating property is expressed as the physical property value of the compression strain region. The Young's modulus E2 of rubber was entered.

  In the simulation method according to the second embodiment, when generating the tire model, the organic fiber is used as the physical property value in the tensile strain region and the physical property value in the compression strain region for each of the membrane elements of the inclined belt layers 20A and 20B. The Young's modulus E1 of the code was input. In the simulation method according to Example 2, the Young's modulus E1 of the organic fiber cord is input as the physical property value of the tensile strain region for each of the membrane elements of the belt reinforcing layer 10 and the carcass ply layer 30, and the compression strain The Young's modulus E2 of the coating rubber was input as the physical property value of the region.

  Furthermore, in the simulation method according to the third embodiment, when generating the tire model, the physical property value of the tensile strain region for each of the film elements of the belt reinforcing layer 10, the inclined belt layers 20A and 20B, and the carcass ply layer 30 is obtained. The Young's modulus E1 of the organic fiber cord was input as the Young's modulus E2 of the coating rubber as the physical property value in the compression strain region.

  In Examples 1 to 3 described above, the Young's modulus E2 of the coating rubber input to each of the belt reinforcing layer 10, the inclined belt layers 20A and 20B, and the carcass ply layer 30 is set to the same value, and organic The Young's modulus E1 of the fiber cord was also set to the same value. Further, the ratio E2 / E1 between the Young's modulus E2 of the coating rubber and the Young's modulus E1 of the organic fiber cord was in the range of 0 <E2 / E1 <0.008.

Table 1 below shows “ΣΔPi ² ” (index) and calculation time (index) indicating calculation accuracy in the simulation method according to the conventional example and Examples 1 to 3.

  In the simulation method according to the conventional example, the same Young's modulus E1 of the organic fiber cord is used for each of the membrane elements of the skeleton member or the reinforcing member of the tire with the physical property value of the tensile strain region and the physical property value of the compression strain region. Therefore, the calculation accuracy was not high.

  On the other hand, in the simulation method according to the embodiment corresponding to the simulation method of the present invention, the accuracy of the calculation result is greatly improved. This is because, by generating a model in which the Young's modulus E2 of the coating rubber is input as the physical property value of the compression strain region for the skeleton member and the reinforcing member of the tire, the bending rigidity and bending deformation are particularly close to those of the actual tire. It has become.

  Here, comparing the result of the conventional example with the result of Example 1, the difference in index is “9”. Further, comparing the result of the conventional example and the result of Example 2, the difference in index is “15”, and the calculation accuracy of Example 2 is improved by an index “6” compared to Example 1. is doing. Further, comparing the result of the conventional example and the result of the example 3, the difference in the index is “31”, and the calculation accuracy of the example 3 is improved by the index “16” compared to the example 2. is doing.

  That is, paying attention to the difference in index between Examples 1 to 3, it can be seen that the result of Example 3 in which the carcass ply layer 30 is defined by the elements of the present invention is particularly effective in improving the calculation accuracy.

  Since the carcass ply layer 30 is a member disposed on the tire side portion among the skeleton member and the reinforcing member of the tire, it can be said that the largest tensile strain and compressive strain are generated when the tire contacts the ground. . That is, the simulation method according to the conventional example suggests that the bending rigidity of the carcass ply layer 30 could not be modeled with high accuracy.

  In the simulation method according to the embodiment, the Young's modulus E2 of the coating rubber is inputted only for the physical property value of the compression strain region for the element defined as the member having the organic fiber cord among the skeleton member or the reinforcing member of the tire. This proves that a significant improvement in calculation accuracy can be achieved.

[Other Embodiments]
Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification.

  For example, in the above-described embodiment, the Young's modulus E2 of the coating rubber input to each of the belt reinforcing layer 10, the inclined belt layers 20A and 20B, and the carcass ply layer 30 is set to the same value, and the Young of organic fiber cord Although the rate E1 is also set to the same value, the Young's modulus E2 of the coating rubber and the Young's modulus E1 of the organic fiber cord input to each may be different. That is, as long as the ratio E2 / E1 between the Young's modulus E2 of the coating rubber and the Young's modulus E1 of the organic fiber cord satisfies the relationship of 0 <E2 / E1 <0.008, any value may be used. Absent.

  Further, the above-described embodiment and modification examples can be combined. As described above, the present invention can be implemented as modifications and changes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Tire, 10 ... Belt reinforcement layer, 20A thru | or 20B ... Inclined belt layer, 30 ... Carcass ply layer

Claims (6)

In a tire including at least one of a skeleton member formed by coating an organic fiber cord with a coating rubber or a reinforcing member formed by coating an organic fiber cord with a coating rubber, the tire is generated by dividing the tire into a finite number of elements. A simulation method using a tire model,
Including the step A of generating the tire model;
Step A includes
Defining at least one of the skeletal member or the reinforcing member as a membrane element, a shell element or a solid element;
Step A2 for inputting the Young's modulus of the organic fiber cord as a physical property value used for calculating the tensile strain and inputting the Young's modulus of the coating rubber as a physical property value used for calculating the compressive strain for the element. A simulation method comprising: The simulation according to claim 1, wherein a ratio E2 / E1 between a Young's modulus E2 of the coating rubber and a Young's modulus E1 of the organic fiber cord is in a range of 0 <E2 / E1 <0.008. Method. 3. The simulation method according to claim 1, wherein, in the step A <b> 1, the inclined belt layer of the tire that is the reinforcing member is defined as any element of a membrane element, a shell element, or a solid element. 4. The process according to claim 1, wherein in step A <b> 1, a belt reinforcing layer of the tire that is the reinforcing member is defined as any one of a membrane element, a shell element, and a solid element. The simulation method described. The said process A1 WHEREIN: The carcass ply layer of the said tire which is the said frame | skeleton member is defined as any element of a membrane element, a shell element, or a solid element, The Claim 1 characterized by the above-mentioned. The simulation method described. A simulation apparatus that executes the simulation method according to claim 1.

Images