JP2006113979A - Simulation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To use a model taking mutual interference between respective members in a tire into consideration for more precisely predicting a lifetime of the tire. <P>SOLUTION: This simulation method is provided with steps for: employing displacement of an overlapping part between a global model 100 and a local model 110 as the sum of displacement of the respective models; considering displacement of the local model 110 in the boundary part of the local model 110 as zero; and predicting the lifetime of the tire according to a finite element method analysis based on the global model 100 and the local model 110. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a simulation method for predicting the progress of a crack generated in a tire using a finite element method.

In recent years, a simulation method for predicting the progress of a crack generated in a tire using a finite element method has been provided. Specifically, in this simulation method, first, a tire model (hereinafter simply referred to as a global model) is set by an assembly of elements capable of numerical analysis, and also by an assembly of elements capable of numerical analysis. A model of cracks occurring in the tire (hereinafter simply referred to as a local model) is set. Then, the behavior of the global model and the local model is analyzed under a predetermined condition, and the progress of cracks occurring in the tire is predicted. In addition, a case 1 of a composite material analysis technique using a finite element method by a superposition mesh method has been reported (for example, see Non-Patent Document 1).
Proceedings of the Computational Engineering Lecture, Vol. 18 (May 2003), “Meso Analysis of Composite Materials Using Polymerization Mesh Method”, P243-246

  However, despite the existence of mutual interference, which is a physical phenomenon, in the behavior between the tire corresponding to the global model and the crack of the tire corresponding to the local model, this simulation method takes this mutual interference into consideration. Therefore, it is difficult to accurately predict the progress of cracks occurring in the tire.

  On the other hand, in the above case 1, an analysis method using a model in which mutual interference existing between members is taken into account is shown. However, this analysis method uses a model that takes into account the mutual interference that exists between each arbitrary member, and does not use a model that takes into account the mutual interference that occurs between each member in the tire. The life of the tire, including the development of cracks, could not be predicted more accurately.

  Therefore, the present invention has been made in view of the above points, and by using a model that takes into account the mutual interference between the members in the tire, a simulation that can more accurately predict the life of the tire It aims to provide a method.

  In order to solve the above problems, the present invention sets a global model in which a tire is modeled by an assembly of elements that can be numerically analyzed, and cracks that occur in the tire due to an assembly of elements that can be numerically analyzed. A first step for setting a modeled local model, a second step for setting the displacement of overlapping portions of the global model and the local model set by the first step as the sum of the displacements of the respective models, and setting by the first step The third step of setting the displacement of the local model at the boundary portion of the generated local model to zero, and the lifetime of the tire by the finite element analysis based on the global model and the local model set by the first to third steps And a fourth step of predicting.

  According to the present invention as described above, the displacement of the overlapping portion of the global model and the local model is set as the sum of the displacements of the respective models, and the displacement of the local model at the boundary portion of the local model is set to zero. The tire life (for example, crack growth at the end of the belt layer, crack growth at the end of the carcass, wire chafer) More accurately, the progress of cracks occurring at the end of the car, the cracks occurring at the end of the nylon chafer, or the cracks occurring at the carcass part located near the shoulder part of the tire) Can be predicted.

  In the above invention, the fourth step is generated in the tire by the finite element method analysis based on the global model and the local model set in the first to third steps and the time series change of the rubber constituting the tire. The progress of cracks may be predicted. Here, rubber has the property of becoming brittle over time. This is because rubber is exposed to oxygen, moisture, and heat entering from the inside or outside of the tire. For this reason, the resistance to the propulsive force that tries to advance the crack generated in the rubber decreases with time. Therefore, the progress of cracks occurring in the tire can be predicted more accurately by using the time series change of rubber.

  In the above invention, the fourth step is generated in the tire by the finite element method analysis based on the global model and the local model set in the first to third steps and the cracking speed of the rubber constituting the tire. The progress of cracks may be predicted. Further, the progress of cracks occurring in the tire may be predicted by a finite element method analysis based on the global model and the local model set in the first step to the third step and the temperature of the rubber constituting the tire. . In this case, since the crack speed and temperature of the rubber are used for the finite element method analysis, the progress of the crack generated in the tire can be predicted more accurately.

  In the above invention, the fourth step includes a step of setting a road surface model obtained by modeling a road surface by an aggregate of elements capable of numerical analysis, and wear of a tread portion generated when the global model rolls the road surface model. Predicting the amount, changing the global model based on the predicted amount of wear, and predicting the progress of cracks in the tire by finite element analysis based on the changed global model. You may prepare. In this case, the progress of cracks occurring in the tire can be predicted more accurately by reflecting the global model changed according to the predicted wear amount in the finite element method analysis.

  ADVANTAGE OF THE INVENTION According to this invention, the progress of the crack of a tire can be estimated more correctly by using the model which considered the mutual interference which exists between each member in a tire.

(Composition of pneumatic tire)
The pneumatic tire 1 in the present embodiment will be described with reference to the drawings. FIG. 1 is a view showing a cross section of a pneumatic tire 1 in the present embodiment. As shown in FIG. 1, a pneumatic tire 1 includes a tread portion 2 having land portions partitioned by grooves, sidewall portions 3 extending inward in the tire radial direction from both ends of the tread portion 2, and sidewall portions 3. A bead core 4 positioned at the inner end in the radial direction, a bead filler 5 embedded in the upper part of the bead core 4 and formed of hard rubber on a fine cut, and the bead core 4 from the tread portion 2 through the sidewall portion 3. A plurality of belt layers 7 extending along the circumferential direction of the tread portion 2 between the inner side of the tread portion 2 and the radially outer side of the carcass 6, and the inner radius of the tread portion 2 and the radius of the belt layer 7 A cap layer 8 that covers the belt layer 7 between the outer side in the direction and a wire chafer 9 that reinforces the folded portion of the carcass 6 are provided.

  The belt layer 7 in the present embodiment includes a rubber 71 and a cord 72 covered with the rubber 71. Similarly, the cap layer 8 also includes a rubber 81 and a cord 82 covered with the rubber 81. A cord 72 (or cord 82) covered with the rubber 71 (or rubber 81) is spirally wound at a small angle with respect to the tire equator CL.

(Computer configuration)
The computer 200 in this embodiment will be described with reference to the drawings. FIG. 2 is a diagram illustrating a configuration of the computer 200 in the present embodiment. As illustrated in FIG. 2, the computer 200 includes an input unit 211 that prompts input of values necessary for simulating tire performance, and a storage unit 212 that stores a program for executing processing by the processing unit 213. The processing unit 213 predicts the tire performance by an analysis method such as a finite element method based on the value input by the input unit 211 and the value stored in the storage unit 212, and the performance predicted by the processing unit 213. And a display unit 214 for displaying the result.

  The processing unit 213 sets a global model 100 in which a tire is modeled by an assembly of elements that can be numerically analyzed. FIG. 3 is a diagram showing the global model 100 in the present embodiment. As shown in FIG. 3, the global model 100 is an aggregate of elements 100a, 100b, 100c. Each element 100a, 100b, 100c... Is data that can be numerically analyzed by the processing unit 213. For example, each of the elements 100a, 100b, 100c,... Includes a film element made up of a two-dimensional triangle / tetragon, or a solid element made up of a three-dimensional tetrahedron. The elements 100a, 100b, 100c,... Define coordinate data, values indicating material characteristics, and the like.

  The processing unit 213 sets the local model 110 using an aggregate of elements that can be numerically analyzed. FIG. 4 is a diagram showing the local model 110 in the present embodiment. As shown in FIG. 4, the local model 110 includes a code model 111 that models a cord provided in a tire, and a crack model 112 that models a crack generated in the tire. Since each element is arranged in the shape of a spider web at the tip 113 of the crack model 112, the stress concentration is reduced. The cord model 111 is obtained by modeling a cord included in the carcass 6, the belt layer 7, the cap layer 8, and the wire chafer 9 and a crack around the cord.

  The processing unit 213 sets the displacement of the overlapping portions of the global model 100 and the local model 110 as the sum of displacements of the respective models (displacement condition 1), and zeros the displacement of the local model 110 at the boundary portion of the local model 110. (Displacement condition 2). Here, FIG. 5 is a diagram showing functions of the global model 100 and the local model 110. As shown in FIG. 5, the function of the global model 100 is uG, and the function of the local model 110 is uL. Further, the overlapping portion of the function of the global model 100 and the function of the local model 110 is set to uG + uL (corresponding to the displacement condition 1). Furthermore, the function uL of the local model 110 at the boundary portion of the local model 110 is set to 0 (corresponding to the displacement condition 2). The above-described processing unit 213 executes the processes of FIGS. 6 and 7 described later under these displacement conditions.

  Based on the global model 100 and the local model 110, the processing unit 213 performs the progress of cracks generated in the tire (for example, the progress of cracks generated at the end T of the belt layer 7, the end of the carcass 6). Progress of a crack generated in 6a, progress of a crack generated in an end portion 9a of a wire chafer 9 (or nylon chafer), or progress of a crack generated in a carcass portion 6b arranged near the shoulder portion 10, tire (See step 5-8).

  The processing unit 213 predicts the progress of cracks occurring in the tire based on the global model 100 and the local model 110 and the time series change of rubber constituting the tire. Here, the time series change of rubber includes a time series change of rubber according to a creep strain characteristic curve described later (see Step 8 and Step 9).

  The processing unit 213 sets a road surface model (not shown) obtained by modeling a road surface by an assembly of elements that can be numerically analyzed, and is generated when the global model 100 rolls the road surface model (not shown). The wear amount of the tread portion 2 is predicted, the shape of the global model 100 and the local model 110 is changed based on the predicted wear amount, and the progress of cracks occurring in the tire based on the changed global model 100 and the local model 110 is observed. Prediction (see Steps 5-8 and 11).

  The processing unit 213 predicts the progress of a crack generated in the tire by a finite element method analysis based on the global model 100 and the local model 110 and the crack speed of the rubber constituting the tire (steps 5-2, 5- 6, 5-7, 5-8). The processing unit 213 predicts the progress of cracks occurring in the tire by a finite element method analysis based on the global model 100 and the local model 110 and the temperature of rubber constituting the tire (steps 4 and 7).

(Simulation method)
The operation of the computer 200 in this embodiment will be described with reference to the drawings. FIG. 6 is a flowchart showing the operation of the computer 200 in the present embodiment. As illustrated in FIG. 6, in step 1, the processing unit 213 sets the global model 100 and the local model 110, and sets the above-described displacement condition 1 and displacement condition 2. The processing unit 213 performs processing described later based on the displacement condition 1 and the displacement condition 2.

  In step 2, the processing unit 213 calculates the stress and strain generated in the tire based on the coordinate data set for each element constituting the global model 100 and the local model 110, values indicating the characteristics of the material, and the like. To do.

  In step 3, the processing unit 213 sets analysis conditions relating to a rolling time during which the global model 100 rolls on a road surface model (not shown).

  In step 4, the processing unit 213 performs thermal analysis of the tire by finite element analysis based on the input tan δ of the rubber sample, the measured value of thermal conductivity, and the measured value of thermal conductivity around the tire. And the temperature in each part of a tire is predicted.

  In step 5, the processing unit 213 calculates a fracture parameter to be described later, thereby predicting a crack speed at which a crack in the rubber progresses, and changing the model at the tip portion 113 of the crack model 112 (destruction parameter calculation process). Execute.

  FIG. 7 is a diagram showing the destruction parameter calculation process in step 5 in the present embodiment. As shown in FIG. 7, in step 5-1, the processing unit 213 calculates the temperature / stress at the tip 113 of the crack model 112, and the calculated temperature (predicted temperature) / stress and the global model 100 are the road surface model. Based on the rolling time of rolling on (not shown), the drag of the rubber against the progressing force to advance the crack in the rubber is calculated.

  In step 5-2, the processing unit 213 prompts the setting of a drag characteristic curve to be described later. FIG. 8 is a diagram showing a drag characteristic curve. The process by which this drag characteristic curve is derived is as follows. First, a cracked rubber sample is placed in an environmental tank maintained at a constant temperature. And the fatigue test of the said rubber | gum is performed and the drag | drug with respect to the said progress force is calculated | required by the degree of the progress force which is going to advance the crack in rubber | gum, and the temperature / time relationship in an environmental tank. Thus, by changing the temperature and time in the environmental tank, a drag characteristic curve showing the relationship between the resistance of rubber and the temperature and time in the environmental tank is derived.

  In Step 5-3, the processing unit 213 shows the rolling time during which the global model 100 rolls on the road surface model (not shown), the predicted temperature at the tip 113 of the crack model 112, and the results shown in FIG. Based on the drag characteristic curve, the drag corresponding to the rolling time and the temperature is specified. On the other hand, the processing unit 213 calculates the J integral based on the calculated stress or strain at the end of the belt layer 7 along the entire circumference of the tire, and uses the calculated J value as the fracture parameter. The fracture parameter is not limited to the J value as a result of J integration, but may be a stress intensity factor, an energy release rate, a result of C integration, a result of T integration, or the like.

  In Step 5-4, the processing unit 213 determines whether or not the calculated J value is larger than the drag calculated in Step 5-1. Further, when the calculated J value is larger than the drag calculated in step 5-1, the processing unit 213 determines that the crack has progressed, and the calculated J value is calculated in step 5-1. If it is smaller than the drag, it is determined that there is no crack growth.

  In step 5-5, the processing unit 213 checks whether or not it is determined in step 5-4 that there is a crack progress. If it is determined in step 5-4 that the crack has progressed, the process proceeds to step 5-7. If it is determined in step 5-4 that the crack has not progressed, the fracture parameter calculation process is performed. finish.

  In step 5-6, the processing unit 213 prompts the setting of a crack rate characteristic curve described later. FIG. 9 is a diagram showing a crack rate characteristic curve. The process by which this crack rate characteristic curve is derived is as follows. First, a cracked rubber sample is placed in an environmental tank maintained at a constant temperature. Then, a fatigue test of the rubber is performed, and the crack speed at which the crack progresses in the rubber is determined based on the calculated value of the fracture parameter and the relationship between temperature and time in the environmental tank. This leads to a crack rate characteristic curve showing the relationship between crack rate-fracture parameter and temperature in the environmental tank.

  In Step 5-7, the processing unit 213, based on the predicted temperature at the tip 113 of the crack model 112 calculated in Step 5-1, the fracture parameter calculated in Step 5-3, and the crack velocity characteristic curve, The cracking speed corresponding to the fracture parameter and the temperature is specified.

  In step 5-8, the processing unit 213 changes the shape of the tip portion 113 of the crack model 112 based on the crack speed specified in step 5-7. The processing unit 213 predicts the progress of cracks occurring in the tire by finite element analysis based on the changed crack model 112 and other models.

  When the destruction parameter calculation process in step 5 ends, the process in step 6 is performed. In step 6, the processing unit 213 prompts input of tan δ of the rubber sample in each part of the tire, a measured value of thermal conductivity, and a measured value of thermal conductivity around the tire. In step 7, the processing unit 213 performs thermal analysis of the tire by finite element analysis based on the input tan δ of the rubber sample, the measured value of thermal conductivity, and the measured value of thermal conductivity around the tire. And the temperature in each part of a tire is predicted.

  In step 8, the processing unit 213 prompts input of a creep strain characteristic curve described later. The process by which this creep strain characteristic curve is derived is as follows. First, a rubber sample constituting each part of the tire is placed in an environmental tank. Then, an internal pressure is applied to the tire. The rubber sample is subjected to a creep test under the condition that a constant load and a constant temperature are applied. By changing the temperature and time in the environmental tank in this creep test, a creep strain characteristic curve showing the relationship between the creep strain of the rubber sample-rubber stress and the temperature and time in the environmental tank is derived.

  In step 9, when internal pressure is applied to the global model 100, the processing unit 213 performs stress analysis by finite element method analysis based on the information including the creep strain characteristic curve set in step 8. A global model 100 and a local model 110 are set according to the analysis result.

  In step 10, the processing unit 213 prompts the setting of a wear amount characteristic curve described later. The process by which this wear characteristic curve is derived is as follows. Specifically, a rubber sample in the tread portion 2 is pressed against the road surface, and the pressure applied to the rubber, the amount of rubber sliding, and the amount of rubber worn (hereinafter simply referred to as the amount of wear) are measured. As a result, a wear amount characteristic curve indicating the wear amount—the pressure applied to the rubber and the slip amount of the rubber is derived.

  In step 11, the processing unit 213 calculates the pressure applied to the tread portion 2 and the slip amount of the tread portion 2 when the global model 100 with a constant load is separated from the road surface model (not shown) by an explicit method in the finite element method analysis. calculate. The processing unit 213 predicts the wear amount of the tread portion 2 corresponding to the calculated pressure and slip amount based on the wear amount characteristic curve set in step 10.

  In step 12, the processing unit 213 changes the global model 100 and the local model 110 based on the predicted wear amount of the tread portion 2. In step 13, when the changed global model 100 and local model 110 satisfy the convergence condition, the processing unit 213 proceeds to the process of step 14, and the changed global model 100 and local model 110 do not satisfy the convergence condition. In this case, the process returns to step 7.

  In step 14, the processing unit 213 executes the same destruction parameter calculation process as in step 5 described above. In step 15, the processing unit 213 confirms whether or not the condition set in step 3 has ended. In addition, the processing unit 213 ends the process when the condition set in Step 3 is completed, and returns to the process in Step 7 when the condition set in Step 3 is not completed.

(Operation and effect of simulation method)
According to the present invention, the displacement of the overlapping portion of the global model 100 and the local model 110 is made the sum of the displacements of the respective models, and the displacement of the local model 110 at the boundary portion of the local model 110 is made zero. Thus, the mutual interference between the global model 100 and the local model 110 is taken into consideration, so that the computer 200 determines the life of the tire (for example, the progress of cracks occurring at the end T of the belt layer 7, the carcass 6). Of cracks occurring at the end 6a of the wire, cracks occurring at the end 9a of the wire chafer 9 (or nylon chafer), or cracks occurring at the carcass portion 6b disposed near the shoulder 10 Progress etc.) can be predicted more accurately.

  Rubber has the property of becoming brittle over time. This is because rubber is exposed to oxygen, moisture, and heat entering from the inside or outside of the tire. For this reason, the drag force against the propulsive force trying to advance the crack generated in the rubber decreases with the passage of time. In the present invention, the time series change of the rubber is used so that the computer 200 can predict the tire life more accurately.

  Further, since the cracking speed and temperature of the rubber related to the destruction of the tire are used for the finite element analysis, the life of the tire can be predicted more accurately. Furthermore, the global model 100 changed by the predicted wear amount is reflected in the finite element method analysis, so that the computer 200 can predict the tire life more accurately.

(Example)
An example of simulation in the present embodiment will be described in detail below. The processing of “rubber time-series change” shown in FIGS. 10 to 13 is steps 8 and 9, the “change in shape of the tread portion” is steps 11 and 12, and the “predicted temperature of each tire portion” is the step. The processing of “4, 6, 7” and “crack propagation at the crack tip” corresponds to steps 5-2 and 5-6, and the processing of “predicted temperature of each portion of tire” corresponds to steps 4 and 7.

  10 to 13 are diagrams showing predicted values (numerator) of the present invention / predicted values (denominator) based on a conventional global model / local analysis when the experimental value is 100. FIG.

  FIG. 10 is a diagram showing the relationship between the predicted value (numerator) of the present invention / conventional predicted value (denominator) until the end X of the two belt layers 7 breaks. In FIG. 10, a radial tire for a passenger car having a size of 185 / 65R14, an internal pressure of 100% with respect to the normal internal pressure, and a load of 120% with respect to the normal load is used, and the room temperature is 45 degrees. The experiment was performed under the condition of a speed of 65 km / h, and a local model for three codes was set in the simulation. As shown in FIG. 10, the predicted value (numerator) of the present invention is closer to the experimental value than the conventional predicted value (denominator), indicating a good result.

  FIG. 11 shows the predicted value (numerator) of the present invention / the conventional predicted value (denominator) until the end X of the three belt layers 7, the end 6a of the carcass 6 and the end 9a of the wire chafer are broken. It is a figure which shows the relationship. In FIG. 11, radial tires for trucks and buses with a size of 11R20, an internal pressure of 100% with respect to the normal internal pressure, and a load of 105% with respect to the normal load are used, and the room temperature is 40 degrees. Experiments were performed under conditions of a speed of 60 km / h and a travel distance of 100,000 km, and a local model corresponding to three codes was set in the simulation. In FIG. 11, a structure in which the end 6 a of the carcass 6 is higher than the end 9 a of the wire chafer 9 is used. As shown in FIG. 11, the predicted value (numerator) of the present invention is closer to the experimental value than the conventional predicted value (denominator), indicating a good result.

  FIG. 12 is a diagram showing the relationship of the predicted value (numerator) / conventional predicted value (denominator) of the present invention until the end 9a of the wire chafer 9 breaks. In FIG. 12, substantially the same conditions as in FIG. 11 are used, but the structure in which the end 6a of the carcass 6 is lower than the end 9a of the wire chafer 9 is used. Some conditions are different in that the model is set. As shown in FIG. 12, the predicted value (numerator) of the present invention is closer to the experimental value than the conventional predicted value (denominator), indicating a good result.

  FIG. 13 shows the prediction value (numerator) of the present invention / the conventional prediction value (denominator) until the end portion X of the four belt layers 7 and the carcass portion 6b arranged near the shoulder portion 10 are broken. It is a figure which shows a relationship. In FIG. 13, a radial tire for a construction vehicle in which the size is 4690R57 and a load of 100% with respect to the regular internal pressure and a load of 120% with respect to the regular load is applied, the room temperature is 45 degrees, Experiments were performed under conditions of a speed of 10 km / h, and a local model for five cords was set. As shown in FIG. 13, the predicted value (numerator) of the present invention is closer to the experimental value than the conventional predicted value (denominator), indicating a good result.

  According to such an embodiment, the displacement of the overlapping portion of the global model 100 and the local model 110 is the sum of the displacements of the respective models, and the displacement of the local model 110 at the boundary portion of the local model 110 is zero. As a result, since the mutual interference between the global model 100 and the local model 110 is taken into consideration, the computer 200 causes the life of the tire (for example, the progress of cracks generated at the end T of the belt layer 7, the carcass, 6 at the end 6a of the wire 6, the crack at the end 9a of the wire chafer 9 (or nylon chafer), or the crack at the carcass portion 6b disposed near the shoulder 10 And the like, and the simulation close to the experiment can be executed.

It is a figure showing the section of the pneumatic tire in this embodiment. It is a figure which shows the structure of the computer in this embodiment. It is a figure which shows the global model in this embodiment. It is a figure which shows the local model in this embodiment. It is a figure which shows the relationship between the global model and local model in this embodiment. It is a figure which shows the process of the computer in this embodiment. It is a figure which shows the destruction parameter calculation process in this embodiment. It is a figure which shows the drag characteristic curve in this embodiment. It is a figure which shows the crack speed characteristic curve in this embodiment. It is a figure which shows the comparative example in this embodiment (the 1). It is a figure which shows the comparative example in this embodiment (the 2). It is a figure which shows the comparative example in this embodiment (the 3). It is a figure which shows the comparative example in this embodiment (the 4).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Tire, 2 ... Tread part, 3 ... Side wall part, 4 ... Bead core, 5 ... Bead filler, 6 ... Carcass, 7 ... Belt layer, 8 ... Cap layer, 9 ... Wire chafer, 10 ... Shoulder part, 100 ... Global model, 110 ... Local model, 111 ... Code model, 112 ... Crack model, 113 ... Tip part, 200 ... Computer, 211 ... Input part, 212 ... Storage part, 213 ... Processing part, 214 ... Display part

Claims (10)

A first step of setting a global model in which a tire is modeled by an aggregate of elements capable of numerical analysis and a local model in which a crack generated in the tire is modeled by an aggregate of elements capable of numerical analysis When,
A second step in which the displacement of overlapping portions of the global model and the local model set in the first step is a sum of displacements of the respective models;
A third step of setting the displacement of the local model at the boundary portion of the local model set in the first step to zero.
And a fourth step of predicting the life of the tire by a finite element method analysis based on the global model and the local model set in the first step to the third step.   The fourth step is generated in the tire by the finite element method analysis based on the global model and the local model set in the first step to the third step and the time series change of the rubber constituting the tire. The simulation method according to claim 1, wherein the progress of a crack is predicted.   The fourth step is generated in the tire by a finite element analysis based on the global model and the local model set in the first to third steps and the crack speed of the rubber constituting the tire. The simulation method according to claim 1, wherein the progress of a crack is predicted.   The fourth step is a crack generated in the tire by a finite element method analysis based on a global model and a local model set in the first step to the third step and a temperature of rubber constituting the tire. The simulation method according to claim 1, wherein the progress of the prediction is predicted.   The fourth step includes a step of setting a road surface model in which a road surface is modeled by an aggregate of elements capable of numerical analysis, and a wear amount of a tread portion generated when the global model rolls the road surface model. Predicting, changing the global model based on the predicted amount of wear, and predicting the progress of cracks occurring in the tire by finite element analysis based on the changed global model. The simulation method according to claim 1, further comprising:   The simulation according to any one of claims 1 to 5, wherein the progress of a crack generated in the tire includes a progress of a crack generated at an end portion of a belt layer provided in the tire. Method.   The simulation method according to claim 1, wherein the progress of the crack generated in the tire includes the progress of a crack generated at an end portion of a carcass provided in the tire. .   The progress of a crack generated in the tire includes a progress of a crack generated in an end portion of a wire chafer provided in the tire. Simulation method.   The progress of a crack generated in the tire includes a progress of a crack generated in an end portion of a nylon chafer provided in the tire. Simulation method. The progress of a crack generated in the tire includes a progress of a crack generated in a carcass disposed near a shoulder portion provided in the tire. The simulation method described in 1.

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