JP2016024588A - Simulation method of pneumatic tire and simulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simulation method by which evaluation close to a result of the durability of a chord member of an actual tire can be obtained compared with a prior art when evaluating the durability of the chord member using a computer, and a simulation device.SOLUTION: When simulating a pneumatic tire, a tire model and a road face model are created, initial tensile stress is imparted to an element of at least a part of a chord reinforcing layer model which is included in the tire model along a longitudinal direction of a chord material, and the deformation analysis of a tire is performed by using the tire model. After that, a value of stress which is received by an evaluation objective element corresponding to the chord material for evaluating the durability of the pneumatic tire, a variation of the stress on a tire circumference, or a time history of the stress is extruded from a result of the deformation analysis as stress information. The durability of the chord material is evaluated on the basis of a magnitude of the stress information.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire simulation method and a simulation apparatus for evaluating the durability of a cord material in a pneumatic tire.

  Various simulation methods for evaluating the durability of a pneumatic tire (hereinafter simply referred to as a tire) using a computer have been performed. Thereby, it is possible to develop a pneumatic tire excellent in durability without trial manufacture of a pneumatic tire. In such a simulation method, the durability of a plurality of cord materials such as a steel belt material, a carcass ply material, and a belt cover material used for a belt cover layer is also evaluated.

For example, a method for predicting the durability of a tire reinforced with a cord material using a computer is known (Patent Document 1).
The above method includes a model setting step of inputting a tire model including a code model in which a code material is modeled by a finite number of elements to a computer, and applying a predetermined internal pressure and load to the tire model, thereby applying the tire model to the tire model. A deformation calculation step for performing deformation calculation, an acquisition step for acquiring a compression strain along the longitudinal direction of each element of the code model included in the analysis target region determined in advance from the deformation calculation step, and the acquired compression strain A prediction step of predicting a damage occurrence location in the analysis target area based on the size of the analysis target area.

JP 2013-35458 A

  However, although the above method can predict the occurrence of damage to some extent based on the compression strain of the code model, the prediction result using this method may differ from the actual tire durability performance result. In some cases, the durability performance of the tire has not been fully evaluated.

  Therefore, the present invention provides a simulation of a pneumatic tire that can obtain an evaluation closer to the result of the durability of the actual cord material than in the conventional case when evaluating the durability of the cord material using a computer. It is an object to provide a method and a simulation apparatus.

One embodiment of the present invention is a method for simulating a pneumatic tire using a computer. The method is
The computer includes a cord reinforcement layer model that reproduces the cord reinforcement layer of a pneumatic tire, creates a tire model that consists of a finite element model that reproduces the pneumatic tire, and a road surface model that reproduces the road surface on which the pneumatic tire contacts the ground And steps to
Applying an initial tensile stress along the longitudinal direction of the cord material to at least some elements of the cord reinforcing layer model, and performing a deformation analysis of the tire using the tire model;
The stress value received by the evaluation target element of the tire model corresponding to the cord material for evaluating the durability of the pneumatic tire by the computer, the fluctuation on the tire circumference of the stress received by the evaluation target element, or the tire model A time history of stress received by the representative element of the evaluation target element rotating on the tire circumference when rolling on the road surface model, as a stress information from the result of the deformation analysis,
The computer includes a step of evaluating the durability of the cord material according to the magnitude of the stress information.

  The stress information is preferably information on stress in at least the longitudinal direction of the cord material.

  In the step of evaluating the durability, it is preferable that the computer evaluates the durability of the cord material using a maximum stress in the fluctuation of the stress or a time history of the stress.

  In the step of evaluating the durability, it is also preferable that the computer evaluates the durability of the cord material by the difference between the maximum stress and the minimum stress in the stress fluctuation or the time history of the stress.

  The initial tensile stress is preferably set so as to match the spring characteristics of the pneumatic tire.

  The initial tensile stress is calculated by performing a heat conduction analysis of the tire model that reproduces the cooling process of the tire after the vulcanization step in the manufacturing process of the pneumatic tire, using the tire model, It is preferable to use the tensile stress of the cord material resulting from thermal shrinkage during the cooling treatment of the cord material.

Another aspect of the present invention is a pneumatic tire simulation apparatus. The simulation device is
A tire model including a cord reinforcing layer model that reproduces a cord reinforcing layer including a cord material of the pneumatic tire, and a road surface that reproduces a road surface on which the pneumatic tire contacts the ground, comprising a finite element model reproducing a pneumatic tire A model creation unit for creating a model;
A deformation analysis unit that applies an initial tensile stress along the longitudinal direction of the cord material to at least some elements of the cord reinforcement layer model, and performs a deformation analysis of the tire using the tire model;
The value of stress received by the evaluation target element of the tire model corresponding to the cord material for evaluating the durability of the pneumatic tire, the fluctuation of the stress received by the evaluation target element on the tire circumference, or the tire model on the road surface A time history of stress received by a representative point of the evaluation target element that rotates on the tire circumference when rolling in, an information acquisition unit that extracts as stress information from the result of deformation analysis of the tire;
An evaluation unit that evaluates the durability of the cord material according to the magnitude of the stress information.

  According to the above-described aspect, an evaluation closer to the result of the durability of the actual cord material of the tire can be obtained as compared with the conventional case.

It is a figure explaining the flow of the simulation method of this embodiment. It is a block block diagram explaining the structure of the simulation apparatus of this embodiment. It is a figure which shows an example of sectional drawing of the tire model created by this embodiment. It is a perspective view of an example of the tire model and road surface model created by this embodiment. It is a figure which shows an example of the stress information obtained by this embodiment. It is a figure which shows the other example of the stress information obtained by this embodiment. (A), (b) is a figure which shows an example of the distortion | strain and tensile stress distribution of the cord material longitudinal direction of the cord reinforcement layer model of a belt cover layer.

  Hereinafter, a simulation method and a simulation apparatus for a pneumatic tire according to the present invention will be described based on embodiments.

FIG. 1 is a diagram for explaining the flow of the simulation method of the present embodiment. Specifically, the computer creates a tire model composed of a finite element model that reproduces a pneumatic tire, and a road surface model that reproduces the road surface on which the pneumatic tire contacts the ground (step S1). The tire model includes a cord reinforcement layer model that reproduces a cord reinforcement layer including a cord material of a pneumatic tire. The computer applies initial tensile stress along at least a part of the cord reinforcement layer model of the tire model along the longitudinal direction of the cord material (step S2). Further, the computer sets boundary conditions for performing deformation analysis (step S3), and performs tire deformation analysis using the tire model to which the initial tensile stress is applied (step S4).
After that, the value of stress received by the evaluation target element of the tire model corresponding to the cord material for evaluating the durability of the pneumatic tire by the computer, the fluctuation on the tire circumference of the stress received by the evaluation target element, or the tire model The time history of the stress received by the representative element of the evaluation target element that rotates on the tire circumference when the wheel is rolled on the road surface model is extracted as stress information from the result of the tire deformation analysis (step S5).
Thereafter, the computer evaluates the durability of the cord material according to the magnitude of the extracted stress information (step S6).

Such a simulation method is realized by the simulation apparatus 10 shown in FIG. FIG. 2 is a block diagram illustrating the configuration of the simulation apparatus 10 according to the present embodiment.
The simulation apparatus 10 is configured by a computer, and includes a computer main body 12, a printer 14, a display 16, and a mouse / keyboard 18. A printer 14, a display 16, and a mouse / keyboard 18 are connected to the computer main body 12. The computer main body 12 includes a storage unit 20 including a RAM, a ROM, a heart disk, and the like, a CPU 22, and an analysis processing unit 24.
The analysis processing unit 24 includes a model creation unit 26, an initial stress application unit 28, a deformation analysis unit 30, an information acquisition unit 32, and an evaluation unit 34. The model creation unit 26, the initial stress application unit 28, the deformation analysis unit 30, the information acquisition unit 32, and the evaluation unit 34 are modules formed by calling a program stored in the storage unit 20 and executing the program by the CPU 22. It is. That is, the analysis processing unit 24 is a software module in which the CPU 22 controls the substantial operation of the analysis processing unit 24.

The model creation unit 26 executes step S1 shown in FIG. 1 and creates a tire model composed of a finite element model reproducing a pneumatic tire and a road surface model reproducing a road surface on which the pneumatic tire contacts.
The initial stress applying unit 28 is a part that executes step S2, and is an initial tensile stress along the longitudinal direction of the cord material on at least a part of the cord reinforcing layer model that reproduces the cord reinforcing layer including the cord material of the pneumatic tire. Is granted.
The deformation analysis unit 30 performs the tire deformation analysis using the tire model to which the initial tensile stress is applied in the portion that executes Step S4.
The information acquisition unit 32 executes step S5, and extracts and acquires information on stress received by the evaluation target element of the tire model corresponding to the cord material for evaluating the durability of the pneumatic tire from the result of the tire deformation analysis. To do.
The evaluation unit 34 executes step S6 and evaluates the durability of the cord material based on the magnitude of the stress information extracted by the information acquisition unit 32.

As described above, in the simulation method and apparatus according to the present embodiment, the cord obtained by applying the initial tensile stress to at least some elements of the cord reinforcing layer model reproducing the cord reinforcing layer including the cord material and performing the deformation analysis. Since the durability of the cord material is evaluated based on the magnitude of the stress information of the reinforcing layer model, as will be described later, an evaluation of durability closer to the actual tire durability result can be obtained as compared with the conventional case. In the conventional simulation method, since the compressive strain that does not actually occur in the cord material may be calculated as the strain acting on the cord reinforcing layer model, the durability of the cord material cannot be sufficiently evaluated.
Hereinafter, the operation of the pneumatic tire simulation method and the simulation apparatus 10 for evaluating the durability of the cord material will be described in detail.

First, the model creation unit 26 creates a tire model composed of a finite element model that reproduces a pneumatic tire and a road surface model that reproduces a road surface on which the pneumatic tire contacts the ground (step S1). FIG. 3 is a diagram illustrating an example of a cross-sectional view of the tire model T created in the present embodiment. FIG. 4 is a perspective view of an example of the tire model T and the road surface model R created in the present embodiment. The tire model T is a model obtained by dividing a model of a pneumatic tire to be analyzed (whether or not it actually exists) by a finite number of small elements. The tire model T may be a three-dimensional model or a two-dimensional axisymmetric model. The two-dimensional axisymmetric model is a model in which a two-dimensional cross-sectional shape is transferred in the tire circumferential direction and the same cross-sectional shape is continuous in the tire circumferential direction.
In the case of the three-dimensional model, for example, a tetrahedral to hexahedral solid element for reproducing a rubber member, a membrane element for reproducing a cord reinforcing layer including a cord material, a shell element, and the like are used as each element. In the case of the two-dimensional axisymmetric model, for example, a triangular or quadrilateral solid element for reproducing a rubber member, a membrane element for reproducing a cord reinforcing layer including a cord material, a shell element, or the like is used as each element. The cord reinforcing layer model is represented by a membrane element and a shell element for reproducing the cord reinforcing layer.

  The tire model T shown in FIG. 3 includes a belt layer model 40 that reproduces the belt layer, a tread rubber model 41 that reproduces the tread rubber member, and a belt cover layer that reproduces the belt cover layer provided outside the belt layer in the tire radial direction. A model 42, a carcass model 44 reproducing a carcass ply, and the like are included.

Each element of the tire model T is composed of numerical data that can be deformed and calculated by the computer device 10, and the node number, node position coordinate, element shape, material constant, and the like of each element are set. And stored in the storage unit 20.
The road surface model R (see FIG. 4) is, for example, a rigid body model.

The initial stress applying unit 28 applies initial tensile stress along the longitudinal direction of the cord material to at least some elements of the cord reinforcing layer model that reproduces the cord reinforcing layer of the pneumatic tire (step S2). In the vulcanization process in the tire manufacturing process, the tire immediately after vulcanization is taken out of the vulcanization mold and the tire is cooled. At this time, the organic fiber cord material provided on the outer side in the tire radial direction of the belt layer The belt cover layer using the heat shrinks, and tensile stress is generated in the belt cover layer. Further, in the molding process during the tire manufacturing process, in order to extend the circumference of the molded raw tire and give tension to the belt layer, the belt layer having the steel cord material in the tire produced from the raw tire, Tensile stress remains.
Therefore, tensile stress is generated in the cord material in the tire. For this reason, in the present embodiment, an initial tensile stress is applied to at least some elements of the cord reinforcing layer model along the longitudinal direction of the cord material.

  The initial tensile stress is preferably set so as to match the spring characteristics of the pneumatic tire, for example. Specifically, the tire spring characteristics when the tire is grounded with a load applied to the road surface (longitudinal spring representing the change in load load with respect to the displacement in the vertical direction of the road surface, the change in the lateral force of the tire with respect to the displacement in the tire width direction) Cord reinforcement using the tire model T and the road surface model R so that the spring characteristics of the tire model T coincide with the lateral spring that represents the change in the longitudinal force of the tire with respect to the displacement in the tire circumferential direction). Deformation analysis is performed to calculate the spring characteristics of the tire while variously changing the initial tensile stress applied to the layer model. Thereby, it is possible to search for an initial tensile stress to be applied to the cord material that reproduces the actual spring characteristics of the tire, and to obtain the initial tensile stress.

  The initial tensile stress can also be calculated by performing a heat conduction analysis of a tire model that reproduces the tire cooling process after the vulcanization process in the manufacturing process of the pneumatic tire using the tire model. For example, the tensile stress of the cord material due to the thermal contraction during the cooling process of the cord material can be calculated by thermal conduction analysis. In this case, it is preferable to perform a heat conduction analysis by giving the tire model T material characteristics such as a thermal conductivity, a thermal expansion coefficient, and a thermal contraction rate. In the present embodiment, the durability of the cord material in the actual tire can be evaluated by applying the initial tensile stress to the tire model T and performing the deformation analysis so as to match the actual tire.

The deformation analysis unit 30 sets a boundary condition for performing deformation analysis (step S3), and then performs deformation analysis (step S4).
The deformation analysis includes a deformation analysis of the tire by internal pressure filling, a deformation analysis in which the tire contacts the road surface, or a dynamic deformation analysis in which the tire rolls on the road surface. The boundary conditions to be set include various conditions necessary for performing deformation calculation of the tire model T. The boundary conditions include, for example, an internal pressure condition and a rim condition of the tire model T when performing tire deformation analysis by internal pressure filling. In addition, when performing deformation analysis of static contact analysis in which the tire contacts the road surface, the tire model T includes internal pressure conditions, rim conditions, load load conditions, camber angles, and the like. In addition to the above conditions, the boundary conditions include the slip angle of the tire model T, the rotational speed of the tire, and / or the tire model T and the road surface model when performing dynamic rolling analysis in which the tire rolls on the road surface. The coefficient of friction with R is included. These conditions are stored in advance in the storage unit 20, and may be acquired by calling the deformation analysis unit 30. Alternatively, the deformation analysis unit 30 may be input by an operator using an input operation system such as the mouse / keyboard 18. May get.

For example, in the deformation analysis by internal pressure filling, the entire matrix expressing the tire model T by combining the stiffness matrix for each element created based on the shape and material characteristics (for example, various elastic constants) of each element of the tire model T Is created. Then, a constant pressure is applied to each node on the tire inner surface facing the tire cavity region of the tire model T. This causes deformation of the tire model T. At this time, stress and strain act on the cord reinforcement layer model of the tire model T.
Further, for example, when the deformation analysis is a ground contact analysis in which the tire model T contacts the road surface model R, the rigidity of each element created based on the shape and material characteristics (for example, elastic modulus) of each element of the tire model T An overall matrix expressing the tire model T is created by combining the matrices. Then, an overall matrix is created in accordance with the conditions to be analyzed for deformation, and the tire model T is gradually approximated to the road surface model R so that the tire model T contacts the road surface model R. Analysis is performed. At this time, stress and strain act on the cord reinforcement layer model of the tire model T.
Further, when the deformation analysis is a rolling analysis in which the tire model T rolls on the road surface model R, the shape and material characteristics (for example, density, elastic modulus, and in some cases, a damping coefficient) of each element of the tire model T An overall matrix representing the tire model T is created by combining the mass matrix and the stiffness matrix created for each element, and in some cases a damping matrix. Then, an equation of motion using the entire matrix is created in accordance with the condition for the deformation analysis, and the deformation analysis is performed by sequentially calculating this equation of motion in increments of a minute time increment Δt. At this time, stress and strain act on the cord reinforcement layer model of the tire model T.
The deformation analysis results (calculation results of stress, strain, etc.) obtained in this way are stored in the storage unit 20.

  The information acquisition unit 32 acquires stress information on the evaluation target element of the tire model T corresponding to the cord material for evaluating the durability of the tire from the result of the deformation analysis described above (step S5). The evaluation target element is input and set in advance by an operator through an input operation system such as the mouse / keyboard 18. For example, in the cross-sectional shape of the tire model T shown in FIG. 3, the belt cover is located on the outer side in the tire radial direction of the belt model 40 reproducing the belt layer and on the inner side in the tire radial direction of the tread rubber model 41 reproducing the tread rubber. An element near the end in the tire width direction of the belt cover layer model 42 reproducing the layer, an element near the end in the tire width direction of the belt model 40, and the like are selected. The selected evaluation target element is not limited to the element of the cord reinforcing layer model to which the initial tensile stress is applied by the initial stress applying unit 28, and the cord reinforcing layer model to which the initial tensile stress is not applied by the initial stress applying unit 28 May be an element.

  Specifically, the stress information includes, for example, the value of stress received by the selected evaluation target element (code reinforcement layer model) when the deformation analysis is a deformation analysis of a tire by internal pressure filling. Further, when the deformation analysis is a ground contact analysis in which the tire model T is brought into contact with the road surface model R, the stress information includes a variation on the tire circumference of a stress received by the selected evaluation target element (code reinforcement layer model). . When the deformation analysis is a rolling analysis in which the tire model T is rolled on the road surface model R, the stress information rotates on the tire circumference when the tire model T is rolled on the road surface model R. It includes a time history of stress received by a representative element (one element on the tire circumference at a different position in the tire circumferential direction among a plurality of elements at the same position on the tire profile cross section) of the evaluation target element.

Such stress information is obtained by extracting and collecting information on the stress in the information on the selected evaluation target element from the result of the deformation analysis stored in the storage unit 20.
FIG. 5 is a diagram illustrating an example of stress information when the deformation analysis is a grounding analysis. FIG. 5 shows the variation on the tire circumference of the stress of the evaluation target element at the end of the belt cover layer in the tire width direction. This stress is a tensile stress in the longitudinal direction of the cord material of the belt cover layer.
FIG. 6 is a diagram illustrating another example of stress information when the deformation analysis is a grounding analysis in which the tire model T is grounded by applying a load to the road surface model R. FIG. 6 shows the variation on the tire circumference of the stress of the evaluation target element at the end of the belt layer in the tire width direction. This stress is a tensile stress in the longitudinal direction of the cord material of the belt layer.
As described above, in the present embodiment, when the deformation analysis is a ground contact analysis, it is possible to obtain a variation in stress at each position on the tire circumference with the circumferential position of the center in the tire ground contact surface being 180 degrees. At this time, it is preferable that the information acquisition unit 32 acquires stress information at least in the longitudinal direction of the cord material. Thereby, as will be described later, a simulation result close to the actual evaluation result of the durability of the cord material can be obtained.

The evaluation unit 34 evaluates the durability of the cord material based on the magnitude of the stress information (step S6). When evaluating the durability of the cord material, for example, the evaluation unit 34 preferably evaluates the durability of the cord material using the maximum stress in the stress fluctuation or the stress time history. In this case, the durability can be evaluated by comparing the maximum stress with the breaking strength of the cord material. It is also preferable that the evaluation unit 34 evaluates the durability of the cord material using the difference between the maximum stress and the minimum stress in the stress fluctuation or the time history of the stress. In this case, a failure due to heat generation of the cord material can be evaluated. D1 and D2 shown in FIGS. 5 and 6 indicate the difference between the maximum stress and the minimum stress.
The evaluation of the durability of the cord material of the present embodiment is to determine whether or not the corresponding portion of the cord material corresponding to the defined evaluation target element is likely to break, or the code corresponding to the defined evaluation target element This includes identifying the location where the corresponding part of the material is most likely to break on the tire circumference, and if multiple evaluation target elements are selected, the cord material breaks most among the evaluation target elements. It also includes identifying the location of elements that are at increased risk.

As described above, in the present embodiment, the durability of the cord material is evaluated by the magnitude of the stress information obtained by the deformation analysis for the following reason.
Under the influence of the tire manufacturing process, an initial tensile stress has already been applied to the cord material in the state before air filling. Along with this, strain (initial strain) is generated in the cord material and the rubber material around the cord material. For this reason, when it is going to evaluate durability of a cord material using a tire model, internal pressure filling, ground deformation analysis, etc. must be performed from the state where initial tensile stress and initial strain were given. However, it is difficult to determine the initial strain and the initial tensile stress so that the initial tensile stress and the initial strain are balanced with each other. For this reason, in this embodiment, the initial stress is not applied to the tire model T, but the initial tensile stress is applied and the deformation analysis such as the internal pressure filling is performed, whereby the tensile stress generated by the deformation analysis is added to the initial tensile stress. Is added, and stress information regarding the cord material that matches the actual durability evaluation of the cord material can be acquired. In this case, the initial strain is not applied, so it is not balanced mechanically, but the stress calculated by the deformation analysis is added to the stress calculated by the deformation analysis because the stress generated by the deformation analysis is added to the initial stress. Is close to the stress acting on the actual cord material.
As in the prior art, when evaluating the durability of the cord material by the magnitude of the strain of the cord material, the strain may indicate compression even when an actual tensile stress is acting on the cord material. FIGS. 7A and 7B are diagrams illustrating an example of strain and tensile stress distribution in the cord material longitudinal direction of the cord reinforcing layer model of the belt cover layer. In this example, the initial tensile stress is applied to the cord reinforcing layer model of the tire model T and the deformation analysis of the internal pressure filling is performed. Even if the tensile stress is applied to the cord reinforcing layer model as shown in FIG. 7B, there is a portion where the strain is compressed as shown in FIG. 7A. In such a case, it is difficult to appropriately evaluate the durability of the cord material due to strain. For this reason, in this embodiment, the durability of the cord material is evaluated based on the magnitude of the stress information of the cord reinforcing layer model.

  As described above, in this embodiment, deformation analysis is performed by applying an initial tensile stress to the tire model T, and the durability of the cord material is evaluated based on the magnitude of the stress information of the cord reinforcing layer model based on the analysis result. As a result, an evaluation closer to the actual result of the durability of the tire can be obtained as compared with the conventional case. At this time, since the stress information is at least stress information in the longitudinal direction of the cord material, it is possible to accurately evaluate the deterioration of durability due to the fracture of the cord material or the heat generation of the cord material.

(Experimental example)
In order to confirm the effect of this embodiment, two tire models were created that reproduced two types of tires A and B having different tire profile shapes. A predetermined initial tensile stress was applied to the belt layer model and the belt cover layer model of the tire model, and the tire model was subjected to internal pressure filling deformation analysis. Thereafter, a deformation analysis in which the tire model is brought into contact with the road surface model was performed, and the durability of the cord material of the belt layer was evaluated based on the magnitude of the stress information of the belt layer model (Example).
On the other hand, the tire model was subjected to internal pressure filling deformation analysis without applying initial tensile stress to the belt layer model and belt cover layer model of the two tire models. Thereafter, a deformation analysis was performed in which the tire model was brought into contact with the road surface model, and the durability of the cord material of the belt reinforcement layer was evaluated based on the magnitude of strain acting on the belt layer model (conventional example).
Each tire model was a three-dimensional model as shown in FIG. 4 with 500 nodes and 800 elements, and the road surface model was a rigid model. From the result of the deformation analysis, stress information and strain information acting on the end of the belt layer model in the tire width direction were obtained. The stress information and the strain information are information on fluctuations on the tire circumference. Evaluation of the durability of the cord material was performed by the difference between the maximum value and the minimum value among the fluctuations of the extracted stress and strain on the tire circumference. The following table expresses the difference (the difference in strain and the difference in stress) regarding the tire B as an index with the tire A as a reference (index 100). The higher the index, the greater the difference.
On the other hand, for the tires A and B, the belt cord material at the end in the tire width direction of the belt layer after running for 5000 km was taken out, and the breaking strength of the belt cord material was measured. The reciprocal of the breaking strength of the tire A was used as a reference (index 100), and the reciprocal of the breaking strength of the tire B was represented by an index to evaluate the durability of the cord material. The higher the index, the lower the durability.

  From the above table, it can be seen that the index of the difference in the stress of the tire B matches the durability of the cord material of the tire B better than the index of the difference in the strain. From this, the effect of this embodiment is clear.

  The pneumatic tire simulation method and simulation apparatus according to the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the spirit of the present invention. Of course it is also good.

DESCRIPTION OF SYMBOLS 10 Simulation apparatus 12 Computer main body part 14 Printer 16 Display 18 Mouse keyboard 20 Memory | storage part 22 CPU
24 analysis processing unit 26 model creation unit 28 initial stress applying unit 30 deformation analysis unit 32 information acquisition unit 34 evaluation unit 40 belt layer model 41 tread rubber model 42 belt cover layer model 44 carcass model

Claims (7)

A method of simulating a pneumatic tire using a computer,
The computer includes a cord reinforcement layer model that reproduces the cord reinforcement layer of a pneumatic tire, creates a tire model that consists of a finite element model that reproduces the pneumatic tire, and a road surface model that reproduces the road surface on which the pneumatic tire contacts the ground And steps to
Applying an initial tensile stress along the longitudinal direction of the cord material to at least some elements of the cord reinforcing layer model, and performing a deformation analysis of the tire using the tire model;
The stress value received by the evaluation target element of the tire model corresponding to the cord material for evaluating the durability of the pneumatic tire by the computer, the fluctuation on the tire circumference of the stress received by the evaluation target element, or the tire model A time history of stress received by the representative element of the evaluation target element rotating on the tire circumference when rolling on the road surface model, as a stress information from the result of the deformation analysis,
And a step of evaluating the durability of the cord material according to the magnitude of the stress information.   The pneumatic tire simulation method according to claim 1, wherein the stress information is at least stress information in a longitudinal direction of the cord material.   3. The pneumatic tire according to claim 1, wherein in the step of evaluating the durability, the computer evaluates the durability of the cord material by using the maximum stress in the fluctuation of the stress or the time history of the stress. Simulation method.   3. The durability of the cord material according to claim 1, wherein in the step of evaluating the durability, the computer evaluates the durability of the cord material by a difference between the maximum stress and the minimum stress in the fluctuation of the stress or a time history of the stress. Pneumatic tire simulation method.   The pneumatic tire simulation method according to any one of claims 1 to 4, wherein the initial tensile stress is set so as to match a spring characteristic of the pneumatic tire.   The initial tensile stress is calculated by performing a heat conduction analysis of the tire model that reproduces the cooling process of the tire after the vulcanization step in the manufacturing process of the pneumatic tire, using the tire model, The pneumatic tire simulation method according to claim 1, wherein a tensile stress of the cord material resulting from thermal contraction during the cooling process of the cord material is used. A pneumatic tire simulation device,
A tire model including a cord reinforcing layer model that reproduces a cord reinforcing layer including a cord material of the pneumatic tire, and a road surface that reproduces a road surface on which the pneumatic tire contacts the ground, comprising a finite element model reproducing a pneumatic tire A model creation unit for creating a model;
A deformation analysis unit that applies an initial tensile stress along the longitudinal direction of the cord material to at least some elements of the cord reinforcement layer model, and performs a deformation analysis of the tire using the tire model;
The value of stress received by the evaluation target element of the tire model corresponding to the cord material for evaluating the durability of the pneumatic tire, the fluctuation of the stress received by the evaluation target element on the tire circumference, or the tire model on the road surface A time history of stress received by a representative point of the evaluation target element that rotates on the tire circumference when rolling in, an information acquisition unit that extracts as stress information from the result of deformation analysis of the tire;
A pneumatic tire simulation apparatus, comprising: an evaluation unit that evaluates durability of the cord material according to the magnitude of the stress information.

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