JP2006160003A - Model analysis device and simulation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a model analysis device capable of analyzing behavior of a tire with a high degree of accuracy and shortening the analysis time. <P>SOLUTION: The model analysis device analyses the model of the tire turned into the limited number of elements. The model of the tire is provided with a model of rubber having characteristic of poisson's ratio of 0.49-0.499. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a model analysis apparatus and a simulation method for analyzing a tire model modeled into a finite number of elements.

  In recent years, there has been provided a model analysis apparatus that analyzes a tire model, a model of a reinforcing material provided in the tire, or a tire and wheel model (see Patent Document 1). Here, the rubber used for the tire is an incompressible material that is not perfect, and its Poisson's ratio is as close as possible to 0.5. The Poisson's ratio of a completely incompressible material is 0.5.

Therefore, the model analysis apparatus can analyze the behavior of the tire with high accuracy by analyzing the tire model including the rubber having the Poisson's ratio characteristic as close as possible to 0.5.
Patent 3314082

  However, since the Poisson's ratio of the rubber is as close as possible to 0.5, the model analysis apparatus cannot analyze the behavior of the tire unless a long time is spent. Specifically, when the explicit method of the finite element method is used for the analysis, the time interval of the analysis time is inversely proportional to the 1/2 power of the compression rigidity of the material. This is generally known as being based on Courant conditions. As a result, when the Poisson's ratio related to the compression rigidity of the rubber approaches 0.5 as much as possible, the compression rigidity of the rubber increases, so the time interval of the analysis time is shortened, resulting in a longer overall analysis time. Become.

  Accordingly, the present invention has been made in view of the above points, and an object thereof is to provide a model analysis apparatus and a simulation method capable of analyzing the behavior of a tire with high accuracy and shortening the analysis time. To do.

  In order to solve the above-described problems, the present invention is a model analysis apparatus that analyzes a tire model modeled into a finite number of elements, and the tire model has a Poisson's ratio of 0.49 to 0.499. It is characterized by comprising a rubber model having characteristics.

  According to the present invention, when the Poisson's ratio of rubber is 0.49 to 0.499, the behavior of the tire can be analyzed with high accuracy and the analysis time can be shortened. Specifically, when the Poisson's ratio of rubber exceeds 0.499 and is as close as possible to 0.5, the behavior of the tire can be analyzed with high accuracy, but the analysis time becomes long. The analysis time is inversely proportional to the 1/2 power of the compression rigidity (for example, bulk modulus) of rubber or the size of the elements constituting the rubber model (this is based on the Courant condition). is there).

  On the other hand, if the Poisson's ratio of the rubber is less than 0.49, the tire behavior cannot be analyzed with high accuracy, but the analysis time is shortened. In the present invention, since the Poisson's ratio of rubber is an appropriate 0.49 to 0.499, the behavior of the tire can be analyzed with high accuracy and the analysis time can be shortened.

  In the above invention, the tire model may include a model of a cord member including a rubber having a characteristic of Poisson's ratio inherent to an actual rubber material and a cord covered with the rubber. In this case, even if the Poisson's ratio of the rubber contained in the cord member is a value specific to the actual rubber material, the Poisson's ratio of the cord contained in the cord member is usually around 0.3. The entire Poisson's ratio of the cord member does not exceed the above 0.499, and the analysis time does not become long.

  In the above invention, the tread portion model including the tire and the tire model of other portions may be separately provided. In this case, if the tread model and the tire model for other parts are provided separately, the tread model elements are reduced and the number of tread model elements is increased. Although the analysis time seems to increase based on the Courant condition, the analysis time can be prevented from increasing because the Poisson's ratio of the rubber is 0.49 to 0.499.

  In the above invention, the tire model may include a model of a cord member having a characteristic that a material constant during compression is smaller than a material constant during tension. When the material constant (for example, elastic modulus) at the time of compression of this cord member is smaller than the material constant at the time of tension, rubber existing around the cord member is greatly compressed. When this rubber is greatly compressed, the Poisson's ratio of the rubber increases. In the present invention, the Poisson's ratio of rubber is 0.49 to 0.499, and the Poisson's ratio of rubber does not exceed the range, so that the analysis time can be prevented from increasing.

  In the above invention, a tire model and a wheel or vehicle body model modeled on a finite number of elements may be combined and analyzed. By combining this tire model with the wheel or body model, the total number of elements increases, so the analysis time seems to increase, but the Poisson's ratio of the rubber is 0.49 to 0.499. As a result, the analysis time can be prevented from increasing.

  In the above invention, the pressure at which the tire model and the road surface model are in contact (hereinafter referred to as “contact pressure”) and the speed at which the tire model slides on the road surface model (hereinafter referred to as “slip speed”). Thus, the friction coefficient between the tire model and the road surface model may be changed. In this case, since the Poisson's ratio of the rubber is 0.49 to 0.499, the behavior of the friction coefficient consisting of the relationship between the contact pressure and the sliding speed is analyzed with high accuracy and the analysis time is shortened. Can do.

  In the above invention, a tire model and a road surface model modeled on a finite number of elements may be combined and analyzed. When the tire comes into contact with the road surface, the rubber contained in the tire is greatly compressed. When this rubber is greatly compressed, the Poisson's ratio of the rubber increases. In the present invention, the Poisson's ratio of rubber is 0.49 to 0.499, and the Poisson's ratio of rubber does not exceed the range, so that the analysis time can be prevented from increasing.

  According to the present invention, the behavior of the tire can be analyzed with high accuracy and the analysis time can be shortened.

[First Embodiment]
(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 the chopping, and the bead core 4 from the tread portion 2 through the sidewall portion 3. And a belt layer 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.

  The belt layer 7 in the present embodiment includes a rubber 7a and a cord 7b covered with the rubber 7a. The carcass 6 also includes rubber and a cord covered with rubber.

(Model structure)
A model 100 (hereinafter referred to as “tire model 100”) of the pneumatic tire 1 in the present embodiment will be described with reference to the drawings. FIG. 2 is a diagram showing a tire model 100 in the present embodiment. As shown in FIG. 2, the tire model 100 is a model in which the pneumatic tire 1 is modeled by an assembly of elements (elements 100 a, 100 b, 100 c...) Capable of numerical analysis, and a tread having grooves formed therein. A model (see T shown in FIG. 2) corresponding to the unit 2 is provided. In addition, the numerical analysis in this embodiment shall use the explicit solution analysis of a finite element method analysis.

  Each element 100a, 100b, 100c... Is data that can be numerically analyzed by the processing unit 213 shown in FIG. For example, each element 100a, 100b, 100c... Includes a two-dimensional triangular / tetragonal membrane element, a shell element, a three-dimensional tetrahedral, pentahedral, or hexahedral solid element. The elements 100a, 100b, 100c,... Define coordinate data, tire material characteristics (for example, the Poisson's ratio, density, elastic modulus, etc. of rubber). The Poisson's ratio of rubber included in the tire in this embodiment is assumed to be 0.49 to 0.499.

  FIG. 3 is a diagram showing a tire model 100, a wheel model 200 (hereinafter referred to as “wheel model 200”), and a road surface model 300 (hereinafter referred to as “road surface model 300”) in the present embodiment. The wheel model 200 is obtained by modeling a wheel by an assembly of elements (elements 200a, 200b, 200c,...) Capable of numerical analysis. The road surface model 300 is obtained by modeling a road surface by a set of elements (elements 300a, 300b, 300c,...) Capable of numerical analysis. The elements 200a, 200b, 200c..., 300a, 300b, 300c... Have the same significance as the elements 100a, 100b, 100c.

  FIG. 4 is a diagram showing a tire model 100 and a vehicle body model 400 (hereinafter referred to as “vehicle body model 400”) in the present embodiment. The vehicle body model 400 is obtained by modeling a vehicle body by an assembly of elements (elements 400a, 400b, 400c...) Capable of numerical analysis.

  In the present embodiment, (1) a single tire model 100, (2) a combination of the tire model 100 and a wheel model 200, (3) a combination of the tire model 100 and a road surface model 300, (4) a tire model 100 and a wheel model 200. And a combination of the road surface model 300, (4) a combination of the tire model 100 and the vehicle body model 400, (5) a combination of the tire model 100, the wheel model 200 and the vehicle body model 400, (6) a tire model 100, a wheel model 200, and a road surface model. Any combination of 300 and body model 400 is used.

(Computer configuration)
A computer 200 (model analysis apparatus) in the present embodiment will be described with reference to the drawings. FIG. 5 is a diagram showing a configuration of the computer 200 in the present embodiment. As shown in FIG. 5, the computer 200 includes an input unit 211, a storage unit 212, a processing unit 213, and a display unit 214.

  The input unit 211 prompts input of values necessary for simulating the behavior of the tire model 100, the wheel model 200, the road surface model 300, and the vehicle body model 400. The storage unit 212 stores a program or the like for executing processing by the processing unit 213. The processing unit 213 analyzes the tire model 100, the wheel model 200, the road surface model 300, and the vehicle body model 400 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. The behavior of any one or a combination of two or more of them is analyzed. The display unit 214 displays the behavior result analyzed by the processing unit 213.

(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 shown in FIG. 6, in step 1, the processing unit 213 sets a tire model (tire model 100) modeled into a finite number of elements. The processing unit 213 in the present embodiment sets a tire model (tire model 100) including rubber having a Poisson's ratio characteristic of 0.49 to 0.499. Further, the processing unit 213 sets a combination of one or more of the wheel model 200, the road surface model 300, and the vehicle body model 400 and the tire model 100 in accordance with the operation instruction.

  In step 2, the processing unit 213 prompts input such as a Poisson's ratio of rubber between 0.49 and 0.499. In step 3, the processing unit 213 prompts input of boundary conditions. Examples of the boundary conditions include use conditions of the pneumatic tire 1 such as air pressure, load, slip angle, speed, or rim width of the pneumatic tire 1. In addition, the input order of step 2 and step 3 is not limited to this order, and may be any order.

  In step 4, the processing unit 213 performs distortion and stress of each element by finite element analysis based on the coordinate data of each element stored in the storage unit 212 and the values input in steps 2 and 3. Analyze etc. Since numerical analysis by finite element method analysis or the like is common, detailed description is omitted. In step 5, the display unit 214 displays the analyzed result.

  FIG. 7 is a diagram showing the relationship between Poisson's ratio and compression rigidity. FIG. 8 is a diagram showing the relationship between Poisson's ratio and analysis time. In FIG. 7, the compression stiffness of rubber or the like with respect to the Poisson's ratio (0.4999) is shown as an index of 100. In FIG. 8, the analysis time for the Poisson's ratio (0.4999) is shown as an index of 100.

  As shown in FIGS. 7 and 8, when the Poisson's ratio is as close as possible to 0.5, the compression rigidity of the rubber increases, so that the time interval of the analysis time is shortened due to the above-described Courant condition. Specifically, when the explicit method of the finite element method is used for the analysis, the time interval of the analysis time is inversely proportional to the 1/2 power of the compression rigidity of the rubber, so the Poisson's ratio is as close as possible to 0.5. As a result, the compression stiffness of the rubber is increased, and the time interval of analysis time is shortened accordingly, and the entire analysis time is lengthened. However, as shown in FIG. 8, when the Poisson's ratio is lowered to a value close to 0.5 to 0.499, the analysis time index is lowered to about 30, and further the Poisson's ratio is lowered to 0.49. The time index drops to 10. Therefore, the processing unit 213 sets the tire model including the rubber based on the rubber having the Poisson's ratio characteristic of 0.49 to 0.499, so that the processing unit 213 reduces the tire analysis time. Can be shortened.

  FIG. 9 is a diagram showing a rubber model 500 composed of an assembly of a finite number of elements. FIG. 10 is a diagram illustrating a relationship between an index of a load applied to the flat plate 600 and a Poisson ratio of the model 500 when the model 500 is pressed against the flat plate 600 and a deflection of 0.5 mm occurs in the model 500. In FIG. 10, the rubber load with respect to the Poisson's ratio (0.4999) is shown as an index of 100. In addition, the measurement was performed several times in a state where rubber having the same shape as the model 500 and having a Poisson's ratio characteristic of 0.4999 was pressed against a steel flat plate. The index of the average load of the actually measured values obtained a plurality of times was 97 ± 3, and the index of the average load and the index of the load of the model 500 under the same conditions were substantially the same. The average load index 97 ± 3 of this measured value varies because of the temperature dependence of the elastic modulus of the rubber, the dimensional accuracy of the rubber used for the actual measurement, the parallelism between the top and bottom surfaces of the rubber, and the rubber and steel This is caused by an error such as a friction coefficient generated between the flat plate and the flat plate.

  As shown in FIG. 10, when the Poisson's ratio is 0.499, the load index is approximately 100. When the Poisson's ratio decreases from 0.499 to 0.49, the load index is 94, and the error between the load index 94 and the original load index 100 is 6%. Further, when the Poisson's ratio is lowered to 0.48, the load index is 83, and the error between the load index 83 and the original load index 100 is 17%.

  Thus, when the Poisson's ratio is in the range of 0.49 to 0.499, the load index within the range is in the range of 94 to 100, and therefore the load index is the original load. It can be seen that there is no significant deviation from the index of 100. Moreover, since the experimental value is also 94 to 100, the experimental value and the calculated value have the same accuracy and can be said to be within an engineering acceptable range. Therefore, when the processing unit 213 sets a tire model including rubber having a Poisson's ratio characteristic of 0.49 to 0.499, the processing unit 213 increases tire behavior (such as tire load). The analysis time can be shortened while analyzing with accuracy.

(Operations and effects of model analyzer and simulation)
According to the present invention, when the Poisson's ratio of rubber is 0.49 to 0.499, the behavior of the tire can be analyzed with high accuracy and the analysis time can be shortened. Specifically, when the Poisson's ratio of rubber exceeds 0.499 and is as close as possible to 0.5, the behavior of the tire can be analyzed with high accuracy, but the analysis time becomes long. On the other hand, if the Poisson's ratio of the rubber is less than 0.49, the tire behavior cannot be analyzed with high accuracy, but the analysis time is shortened. In the present invention, since the Poisson's ratio of rubber is an appropriate 0.49 to 0.499, the behavior of the tire can be analyzed with high accuracy and the analysis time can be shortened.

  Further, the combination of the tire model 100 and the wheel model 200 or the vehicle body model 400 increases the total number of elements, so that the analysis time seems to increase, but the Poisson's ratio of the rubber is 0.49-0. By being 499, the analysis time can be prevented from increasing.

  Furthermore, when the rubber contained in the tire is greatly compressed by the contact of the pneumatic tire with the wheel or the road surface, the Poisson's ratio of the rubber is increased, but the Poisson's ratio of the rubber is 0.49 to 0.499. As a result, the Poisson's ratio of the rubber does not exceed the range, so that the analysis time can be prevented from increasing.

[Second Embodiment]
In the first embodiment, the Poisson's ratio of the rubber is 0.49 to 0.499, whereas in this embodiment, only the Poisson's ratio of the rubber (coating rubber) constituting the belt layer 7 or the carcass 6 is 0. It is different in that it is 499916.

  FIG. 11 is a view showing a cross section of the tire model 100 in the present embodiment. Since the contents other than those shown in FIG. 11 are the same as those in the first embodiment, detailed description thereof is omitted.

  As shown in FIG. 11, a rubber member (coating rubber) constituting the belt layer 7 or the carcass 6 and a cord member including a cord and a model of other members are composed of a finite number of elements having equivalent rigidity. . Only the Poisson's ratio of the rubber (coating rubber) constituting the belt layer 7 or the carcass 6 is a value unique to the actual rubber material, and the Poisson's ratio of the other rubber is 0.49 to 0.499. To do.

  Here, the Poisson's ratio in the case where the rubber is not modeled alone and all the materials are modeled by a finite number of elements having equivalent rigidity is calculated by the following formulas 1 and 2.

νL = νf · Vf + νm (1-Vf) Equation 1
νT = νL (ET / EL) ... Equation 2
Here, νL represents the Poisson's ratio in the chord direction. νT represents the Poisson's ratio in the direction perpendicular to the chord direction. νf represents the Poisson's ratio of the cord. νm represents the Poisson's ratio of rubber. Vf represents the volume content in the direction perpendicular to the cord direction. EL indicates the Young's modulus in the cord direction. ET represents the Young's modulus perpendicular to the cord direction.

  As shown in Formula 1 and Formula 2, the Poisson ratio of the pneumatic tire 1 is a value between the Poisson ratio of rubber and cord. This also applies to the tire model 100. Thereby, even if the Poisson's ratio of the rubber contained in the cord member (for example, the carcass 6 and the belt layer 7) is a value unique to the actual rubber material, for example, 0.49999, it is included in the cord member. Since the Poisson's ratio of the cord is usually around 0.3, the overall Poisson's ratio of the cord member does not exceed 0.499. For this reason, even if the Poisson's ratio of the rubber contained in the cord member is 0.499916, the analysis time can be prevented from increasing.

[Third Embodiment]
In the second embodiment, the tire model 100 is configured by a finite number of elements having equivalent rigidity, but in the present embodiment, the model 110 of the tread portion 2 (hereinafter referred to as “tread model 110”), This is different in that the model 120 of the pneumatic tire 1 other than the tread portion 2 (hereinafter referred to as the “non-tread model 120”) is configured separately.

  FIG. 12 is a view showing a cross section of the tire model 100 in the present embodiment. Since the contents other than those shown in FIG. 12 are the same as those in the first embodiment, detailed description thereof is omitted.

  As shown in FIG. 12, the tire model 100 includes a tread model 110 and a non-tread model 120 separately. The size of the elements 110a, 110b, 110c... Constituting the tread model 110 is smaller than the size of the element 100a constituting the tread portion 2 shown in FIG. 11, and the number of elements constituting the tread model 110 is shown in FIG. There are more elements than the tread portion 2 shown.

  In this case, the tread model 110 and the non-tread model 120 are separately provided, and the elements of the tread model 110 constitute the tread portion 2 when the tread model and the non-tread model are integrated as shown in FIG. Since it is smaller than the element 100a and the number of elements of the tread model 110 is larger than that of the element 100a configuring the tread portion 2 shown in FIG. Since the Poisson's ratio is 0.49 to 0.499, the analysis time can be prevented from increasing.

[Fourth Embodiment]
In the present embodiment, the tire model 100 includes a model of a cord member having a characteristic that the material constant during compression is smaller than the material constant during tension. Since the contents other than the present embodiment are the same as those of the other embodiments, detailed description thereof is omitted.

  When the material constant (for example, elastic modulus) at the time of compression of this cord member is smaller than the material constant at the time of tension, rubber existing around this cord member is greatly compressed. When this rubber is greatly compressed, the Poisson's ratio of the rubber increases. In the present invention, the Poisson's ratio of rubber is 0.49 to 0.499, and the Poisson's ratio of rubber does not exceed the range, so that the analysis time can be prevented from increasing.

[Fifth Embodiment]
In the present embodiment, the processing unit 213 uses the pressure at which the tire model 100 is in contact with the road surface model 300 (hereinafter referred to as “contact pressure”) and the speed at which the tire model 100 slides on the road surface model 300 (hereinafter referred to as “slip”). The friction coefficient generated between the tire model 100 and the road surface model 300 is analyzed. Since the contents other than the present embodiment are the same as those of the other embodiments, detailed description thereof is omitted.

  In this case, since the Poisson's ratio of the rubber is 0.49 to 0.499, the behavior of the friction coefficient consisting of the relationship between the contact pressure and the sliding speed is analyzed with high accuracy and the analysis time is shortened. can do.

[Example 1]
An analysis example 1 will be described in detail below. FIG. 13 is a diagram illustrating an analysis result of vertical load (force generated in the vertical direction of the tire model 100) generated in the tire model 100 when the tire model 100 makes one rotation on the road surface. In FIG. 13, a model of a radial tire for a passenger car in which the internal pressure is 200 kPa, the rim width is 6 J, and the deflection is 20 mm was used. In addition, the vertical load generated on the tire when the radial tire for a passenger car rotates once on the road surface when the size is 205 / 55R15, the internal pressure is 210 kPa, the rim width is 6.5 J, and the deflection is 20 mm. The measured value of is shown. In FIG. 13, the average value of the measured values of the vertical load for one rotation of the tire is indicated by an index of 100. In addition, since the wheel model is modeled as a rigid body, there is no influence on the length of the analysis time.

  As shown in FIG. 13, under the analysis condition 1-1, the Poisson ratio of rubber is the same value as the Poisson ratio of rubber in an actual tire. The analysis time in the analysis condition 1-1 is indicated by an index of 100. In analysis condition 1-2, the Poisson's ratio of all rubbers is set as 0.499. In analysis condition 1-3, the Poisson's ratio of all rubbers is set to 0.49. In analysis conditions 1-4, the Poisson's ratio of all rubbers is set to 0.48. In the analysis condition 1-5, the Poisson's ratio of rubber is set to a value specific to the actual rubber material, for example, 0.49999, for each shell element assembly having equivalent rigidity of the cord member such as the belt layer and the carcass. In addition, the Poisson's ratio of rubber is set to 0.49 for the other solid element aggregates.

  Thus, when the analysis condition 1-1 is used, it can be seen that the vertical load index, which is the analysis result, is within the fluctuation range of the measured value index, and the accuracy of the analysis is good. When the analysis conditions 1-2, 1-3, and 1-5 are used, the index of the vertical load as the analysis result is within the fluctuation range of the index of the actual measurement value, and the index of the analysis time is the analysis condition. It turns out that it has decreased significantly rather than 1-1. Moreover, when analysis condition 1-4 is used, although the index of analysis time is significantly smaller than that of analysis condition 1-1, the index of the vertical load as the analysis result is not within the fluctuation range of the index of the actual measurement value. It can be seen that the accuracy of the analysis is poor.

  Therefore, when the Poisson's ratio of rubber is in the range of 0.49 to 0.499, the behavior of the tire can be analyzed with high accuracy and the analysis time can be shortened. Further, even if the Poisson's ratio of the rubber contained in the cord member is a value specific to the actual rubber material, for example, 0.49999, the Poisson's ratio of the cord contained in the cord member is 0.35. Therefore, the entire Poisson's ratio of the cord member does not exceed 0.499, and the analysis time does not become long.

[Example 2]
The analysis example 2 will be described in detail below. FIG. 14 is a diagram illustrating an analysis result of the lateral force generated in the tire model 100 when the tire model 100 makes one turn on the road surface. In FIG. 14, a model of a radial tire for a passenger car in which the internal pressure is 210 kPa, the rim width is 6 J, and the deflection is 20 mm was used. In addition, when the size is 195 / 65R15, the internal pressure is 200 kPa, the rim width is 6 J, and the deflection is 20 mm, the lateral force generated in the tire when the radial tire for a passenger car makes one turn on the road surface is measured. Values are shown. In FIG. 14, the average value of the measured lateral force for one rotation of the tire is indicated by an index of 100. Further, the tread model 110 and the non-tread model 120 were separately provided, and the analysis was performed in a state where these models were joined.

  As shown in FIG. 14, in the analysis condition 2-1, the Poisson's ratio of rubber is the same value as the Poisson's ratio of rubber in an actual tire. The analysis time in the analysis condition 2-1 is indicated by an index of 100. In analysis condition 2-2, the Poisson's ratio of all rubbers is set to 0.49. In analysis condition 2-3, the Poisson's ratio of all the rubbers is set as 0.49, and the elastic modulus (material constant) when the carcass 6 is compressed is set as 1/4 of the elastic modulus (material constant) during tension. In addition, the elastic modulus (material constant) at the time of compression of the belt layer 7 is set as ½ of the elastic modulus (material constant) at the time of tension.

  Thus, when the analysis condition 2-1 is used, it can be seen that the lateral force index, which is the analysis result, is within the fluctuation range of the measured value index, and the accuracy of the analysis is good. When the analysis conditions 2-2 and 2-3 are used, the lateral force index, which is the analysis result, is within the fluctuation range of the actually measured index, and the analysis time index is more than the analysis condition 2-1. It can be seen that the number has decreased significantly.

  Therefore, when the size of the elements constituting the tread model 110 is smaller than the size constituting the non-tread model 120 and the number of elements constituting the tread model 110 is larger than the number of elements constituting the non-tread model 120. Although it seems that the analysis time increases based on the above-mentioned Courant condition, the analysis time can be prevented from increasing because the Poisson's ratio of the rubber is within the range of 0.49 to 0.499.

  In addition, when the elastic modulus at the time of compression of the cord member including the carcass 6 and the belt layer 7 is smaller than the elastic modulus at the time of tension, the rubber existing around the cord member is greatly compressed, and the Poisson's ratio of the rubber is increased. Although increased, the Poisson's ratio of the rubber does not exceed the range of 0.49 to 0.499, so that the analysis time can be prevented from increasing.

[Example 3]
Example 3 of analysis will be described in detail below. FIG. 15 is a diagram illustrating an analysis result of a lateral force generated in the tire model 100 when the tire model 100 makes one revolution on the road surface at a slip angle of 1 degree and then makes one revolution. In FIG. 15, a model of a radial tire for a passenger car in which the internal pressure is 200 kPa, the rim width is 6 J, and the deflection is 20 mm was used. A tire in which a radial tire for a passenger car in which the size is 195 / 70R15, the internal pressure is 200 kPa, the rim width is 6 J, and the deflection is 20 mm is rotated once more after rotating once on the road surface. The measured value of the lateral force generated is shown. In FIG. 15, the average value of the measured lateral force for one rotation of the tire is indicated by an index of 100. The wheel is made of an aluminum alloy, and the model of the wheel is made up of an assembly of solid elements.

  As shown in FIG. 15, in the analysis condition 3-1, the Poisson ratio of rubber is the same value as the Poisson ratio of rubber in an actual tire. The analysis time in the analysis condition 3-1 is indicated by an index of 100. In analysis condition 3-2, the Poisson's ratio of all rubbers is set to 0.49.

  Thus, when the analysis condition 3-1 is used, it can be seen that the lateral force index, which is the analysis result, is within the fluctuation range of the actually measured index, and the analysis accuracy is good. When analysis condition 3-2 is used, the lateral force index, which is the analysis result, is within the fluctuation range of the actual value index, and the analysis time index is significantly smaller than analysis condition 2-1. I understand that

  Therefore, by combining the tire model 100 and the wheel model 200, the total number of elements increases, so the analysis time seems to increase, but the Poisson's ratio of rubber is 0.49 to 0.499. Thus, the analysis time can be prevented from increasing.

[Example 4]
The analysis example 4 will be described in detail below. FIG. 16 is a diagram showing an analysis result of the longitudinal load (force generated in the rotation direction of the tire model 100) generated in the tire model 100 when the tire model 100 makes one rotation while braking on the road surface with a slip rate of 10%. . In FIG. 16, a model of a radial tire for a passenger car in which the internal pressure is 200 kPa, the rim width is 5.5 J, and the deflection is 20 mm is used. A radial tire for a passenger car having a size of 185 / 70R14, an internal pressure of 200 kPa, a rim width of 5.5 J, and a deflection of 20 mm makes one rotation while braking on the road surface with a slip rate of 10%. The actual measured value of the longitudinal load generated in the tire in this case is shown. In FIG. 16, the average value of the measured values of the longitudinal load for one rotation of the tire is indicated by an index of 100. Further, the friction coefficient generated between the tire model 100 and the road surface model 300 is set as a function of the contact pressure and the slip speed.

  As shown in FIG. 16, in the analysis condition 4-1, the Poisson's ratio of rubber is the same value as the Poisson's ratio of rubber in an actual tire. The analysis time under the analysis condition 4-1 is indicated by an index of 100. In analysis condition 4-2, the Poisson's ratio of all rubbers is set to 0.49.

  Thus, when the analysis condition 4-1 is used, it can be understood that the index of the longitudinal load as the analysis result is within the fluctuation range of the index of the actually measured value, and the accuracy of the analysis is good. Further, when analysis condition 4-2 is used, the index of the longitudinal load as the analysis result is within the fluctuation range of the index of the actual measurement value, and further, the index of analysis time is significantly reduced from that of analysis condition 4-1. I understand that

  Therefore, since the Poisson's ratio of the rubber is 0.49 to 0.499, it is possible to analyze the behavior of the friction coefficient consisting of the relationship between the contact pressure and the sliding speed with high accuracy and shorten the analysis time.

[Example 5]
The analysis example 5 will be described in detail below. FIG. 17 is a diagram illustrating an analysis result of the vertical load generated in the tire model 100 when the tire model 100 rotates once on the road surface model 300 formed of asphalt. In FIG. 17, a model of a radial tire for a passenger car in which the internal pressure is 200 kPa, the rim width is 6 J, and the load is 4 kPa is used. In addition, when the size is 195 / 65R14, the internal pressure is 200 kPa, the rim width is 6 J, and the load is 4 kPa, the measurement of the vertical load generated on the tire when the radial tire for a passenger car makes one turn on the road surface Values are shown. In FIG. 17, the average value of the measured values of the vertical load for one rotation of the tire is indicated by an index of 100.

  As shown in FIG. 17, in the analysis condition 4-1, the Poisson ratio of rubber is the same value as the Poisson ratio of rubber in an actual tire. The analysis time in the analysis condition 5-1 is indicated by an index of 100. In analysis condition 5-2, the Poisson's ratio of all rubbers is set to 0.49.

  Thus, when the analysis condition 5-1 is used, it can be seen that the vertical load index, which is the analysis result, is within the fluctuation range of the actually measured index, and the analysis accuracy is good. In addition, when analysis condition 5-2 is used, the index of the vertical load, which is the analysis result, is within the fluctuation range of the index of the actual measurement value, and the index of analysis time is significantly reduced from that of analysis condition 5-1. I understand that

  Therefore, the tire model 100 and the road surface model 300 are combined to increase the total number of elements, so that the analysis time seems to increase, but the Poisson's ratio of the rubber is 0.49 to 0.499. Thus, the analysis time can be prevented from increasing.

[Example 6]
Example 6 of analysis will be described in detail below. FIG. 18 is a diagram illustrating an analysis result of the vertical load generated in the tire model 100 when the tire model 100 is mounted on the vehicle body model 400 and makes one turn on the road surface. In FIG. 18, a model of a radial tire for a passenger car in which the internal pressure is 200 kPa and the rim width is 6 J is used. This passenger car radial tire model is mounted on a body model 400 having a front suspension of a McPherson strut and a rear suspension of a torsion beam.

  In addition, an actual measurement value of the vertical load generated in the tire when the radial tire for a passenger car rotates once on the road surface when the size is 195 / 65R14, the internal pressure is 200 kPa, and the rim width is 6 J is shown. . This passenger car radial tire is also mounted on a car body having a McPherson strut front and a torsion beam rear suspension. In FIG. 18, the average value of the measured values of the vertical load for one rotation of the tire is indicated by an index of 100.

  As shown in FIG. 18, in the analysis condition 6-1, the Poisson ratio of rubber is the same value as the Poisson ratio of rubber in an actual tire. The analysis time in the analysis condition 6-1 is indicated by an index of 100. In analysis condition 6-2, the Poisson's ratio of all rubbers is set to 0.49.

  Thus, when the analysis condition 6-1 is used, it can be seen that the vertical load index, which is the analysis result, is within the fluctuation range of the actually measured index, and the analysis accuracy is good. Further, when the analysis condition 6-2 is used, the index of the vertical load as the analysis result is within the fluctuation range of the index of the actual measurement value, and the analysis time index is significantly smaller than the analysis condition 6-1. I understand that

  Therefore, the tire model 100 and the vehicle body model 400 are combined to increase the total number of elements, so that the analysis time seems to increase, but the Poisson's ratio of the rubber is 0.49 to 0.499. Thus, the analysis time can be prevented from increasing.

It is a figure showing the section of the pneumatic tire in this embodiment. It is a figure showing a tire model in this embodiment. It is a figure which shows the tire model in this embodiment, a wheel model, and a road surface model. It is a figure which shows the vehicle body model in this embodiment. It is a figure which shows the structure of the computer in this embodiment. It is a figure which shows operation | movement of the computer in this embodiment. It is a figure which shows the relationship between the Poisson's ratio and compression rigidity in this embodiment. It is a figure which shows the relationship between the Poisson's ratio and analysis time in this embodiment. It is a figure which shows the model in this embodiment. It is a figure which shows the relationship between the Poisson's ratio and load in this embodiment. It is a figure showing the section of the tire model in this embodiment. It is a figure showing the section of the tire model in this embodiment. It is a figure which shows the analysis result in this embodiment. It is a figure which shows the analysis result in this embodiment. It is a figure which shows the analysis result in this embodiment. It is a figure which shows the analysis result in this embodiment. It is a figure which shows the analysis result in this embodiment. It is a figure which shows the analysis result in this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 2 ... Tread part, 3 ... Side wall part, 4 ... Bead core, 5 ... Bead filler, 6 ... Carcass, 7 ... Belt layer, 100 ... Tire model, 110 ... Tread model, 120 ... Outside tread model , 200 ... computer, 200 ... wheel model, 211 ... input unit, 212 ... storage unit, 213 ... processing unit, 214 ... display unit, 300 ... road surface model, 400 ... car body model

Claims (16)

A model analysis device for analyzing a tire model modeled on a finite number of elements,
The tire analysis model includes a rubber model having a Poisson's ratio characteristic of 0.49 to 0.499.   The model analysis apparatus according to claim 1, wherein the tire model includes a model of a cord member including a rubber having a characteristic of a Poisson ratio specific to an actual rubber material and a cord covered with the rubber. .   The model analysis apparatus according to claim 1, wherein a model of a tread portion in which the tire is included and a model of a tire of another portion are separately provided.   4. The model according to claim 1, wherein the tire model includes a model of a cord member having a characteristic that a material constant during compression is smaller than a material constant during tension. 5. Analysis device.   The model analysis apparatus according to claim 1, wherein the analysis is performed by combining the tire model and a wheel model modeled on a finite number of elements.   The model analysis apparatus according to claim 1, wherein the analysis is performed by combining the tire model and a road surface model modeled into a finite number of elements.   The friction coefficient between the tire model and the road surface model is changed according to the pressure at which the tire model and the road surface model are in contact with each other and the speed at which the tire model slides on the road surface model. The model analysis apparatus according to any one of claims 1 to 6, wherein the model analysis apparatus includes:   The model analysis apparatus according to claim 1, wherein the analysis is performed by combining the tire model and a vehicle body model modeled into a finite number of elements. A simulation method for analyzing a tire model modeled on a finite number of elements,
The tire model includes a rubber model having a Poisson's ratio characteristic of 0.49 to 0.499.   The simulation method according to claim 9, wherein the tire model includes a model of a cord member including a rubber having a characteristic of a Poisson ratio specific to an actual rubber material and a cord covered with the rubber.   11. The simulation method according to claim 9, wherein a model of a tread portion including the tire and a model of a tire of another portion are separately provided.   The simulation according to any one of claims 9 to 11, wherein the tire model includes a model of a cord member having a characteristic that a material constant during compression is smaller than a material constant during tension. Method.   The simulation method according to claim 9, wherein analysis is performed by combining the tire model and a wheel model modeled on a finite number of elements.   The simulation method according to claim 9, wherein analysis is performed by combining the tire model and a road surface model modeled into a finite number of elements.   The friction coefficient between the tire model and the road surface model is changed according to the pressure at which the tire model and the road surface model are in contact with each other and the speed at which the tire model slides on the road surface model. The simulation method according to any one of claims 9 to 14, wherein the simulation method is performed. The simulation method according to claim 9, wherein analysis is performed by combining the tire model and a vehicle body model modeled into a finite number of elements.

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