JP5887696B2 - Tire simulation method - Google Patents

Description

  The present invention relates to a technique for analyzing a tire using a computer.

  Predicting various performances of tires or physical quantities related thereto by numerical analysis such as a finite element method by analysis using a computer is useful for improving performance and improving development efficiency. Among these, as a simulation for predicting the performance of the tire, there is a simulation for detecting the rigidity of the blocks constituting the tread portion of the tire. For example, Patent Document 1 describes a tire tread portion simulation method in which a deformation simulation is performed using a tread model in which at least a part of a tire tread portion is modeled with a finite number of elements. This simulation method sets the tread model, which is formed in a substantially rectangular parallelepiped shape composed of a plurality of elements, and at least a pair of main sides facing each other at the same position, and is modeled by providing nodes at the same position. A deformation simulation is performed by giving a periodic boundary condition, and the rigidity of the tire tread portion is calculated from the result of the deformation simulation. Moreover, the small block which comprises a tread part and becomes a repeating unit of the same shape as a part of tire tread is illustrated.

  In Patent Document 2, a tread to be analyzed is divided in three axial directions with a preselected dimension, and the divided cells are classified into a filled cell, an empty cell, and a partially filled cell. Summarize as piles in the (vertical) direction, determine the formula to be applied based on the type of cells making up each pile, calculate the force of each pile based on the formula, and evaluate performance based on that value It is described to do.

Japanese Patent Laid-Open No. 2005-186791 JP 2000-255226 A

  As in Patent Literature 1, the rigidity of the target region can be efficiently calculated by dividing the tread portion into blocks and specifying the target whose rigidity is to be calculated. However, in the method described in Patent Document 1, since the rigidity is calculated by dividing the target block into each element and analyzing it, the calculation amount increases and the calculation takes time.

  The method described in Patent Document 2 also increases the amount of calculation because the block is divided into cells of a predetermined size. Here, since the rigidity is calculated by calculating the characteristic value of the block based on the number of cells, the calculation can be simplified to a certain extent, but the block is divided into three axis directions, There is a limit to reducing the amount of calculation, for example, it is necessary to calculate the piles separately.

  The present invention has been made in view of the above, and an object of the present invention is to calculate the rigidity of a tire block portion with high accuracy while reducing the amount of calculation in a tire simulation using a computer.

  In order to solve the above-described problems and achieve the object, a tire simulation method according to the present invention includes a computer, a shape acquisition step of acquiring a shape of a block constituting a tire tread to be calculated, and a computer. The block is constituted by a dividing step for dividing the block into strips, a strip stiffness calculating step for calculating the stiffness of each strip divided by the computer based on the dimension parameter of the strip, and the computer. And evaluating the overall rigidity of the block by summing the rigidity of the plurality of strips.

  Thereby, since the shape to be calculated can be divided into simple shapes, the rigidity can be easily calculated. Further, the rigidity of the block portion of the tire can be calculated with high accuracy while reducing the amount of calculation.

  Here, in the dividing step, it is preferable that a cut surface for dividing the block into strips is a surface orthogonal to the tire width direction or a surface orthogonal to the tire circumferential direction. Thereby, the rigidity of a block can be evaluated more appropriately.

  The strip rigidity calculating step preferably calculates the rigidity of the strip based on the dimension parameter of the strip and the elastic modulus of the material. Thereby, the rigidity of the strip can be calculated more accurately and easily, and the rigidity of the block can be calculated accurately.

  Moreover, the said block is deform | transforming by shear deformation, It is preferable that the said division | segmentation step makes the cut surface which divides | segments the said block into a strip parallel to a shear direction. Thereby, the rigidity in the shear direction can be more accurately evaluated, and the rigidity of the block can be accurately calculated.

  In the strip rigidity calculation step, it is preferable to calculate the rigidity of the strip by using a calculation function for outputting the stiffness using the shape parameter of the strip as a variable. Thereby, the rigidity can be calculated by simpler calculation, and the rigidity of the block can be calculated accurately.

  Further, the calculation function is preferably created in advance based on the result of calculating the rigidity of a typical strip shape. Thereby, the rigidity can be calculated by simpler calculation, and the rigidity of the block can be calculated accurately.

  In the dividing step, the width of the strip may be divided by a width that is equal to or less than 10% of a representative size based on the length of the block in a direction orthogonal to a cutting plane that divides the block into strips. preferable. Accordingly, the rigidity of the strip can be calculated more accurately, and the rigidity of the block can be calculated accurately.

  Moreover, it is preferable that the strip rigidity calculating step includes at least a ratio of the height and length of the strip cross section to the parameter of the strip dimensions. Thereby, the rigidity of the strip can be calculated more accurately, and the rigidity of the block can be calculated accurately.

  Further, the block has a shape including an inclined portion inclined with respect to a plane parallel to the tire width direction, and the strip rigidity calculating step is calculated when the strip is a portion obtained by dividing only the inclined portion. It is preferable to execute a process of multiplying the determined rigidity by a coefficient. Thereby, the rigidity of the strip can be calculated more accurately, and the rigidity of the block can be calculated accurately.

  In the dividing step, when there are materials having different elastic moduli in the cross section of the strip, it is preferable to further divide at least a boundary having a different elastic modulus as a cut surface. Thereby, the rigidity of the strip can be calculated more accurately, and the rigidity of the block can be calculated accurately.

  Further, the dividing step further divides the strip in a direction orthogonal to a cutting plane that divides the block into strips to form divided strips, and the strip rigidity calculating step includes, for each of the divided strips, the divided strips. It is preferable to calculate the rigidity of the divided strip based on the dimension parameter, and calculate the rigidity of the strip from the calculated rigidity of the divided strip. Thereby, the rigidity of the strip can be calculated more accurately, and the rigidity of the block can be calculated accurately.

  The strip rigidity calculating step preferably calculates the rigidity of the divided strip by using a calculation function that outputs a stiffness using the shape parameter of the divided strip as a variable. Accordingly, the rigidity of the strip can be calculated by simpler calculation, and the rigidity of the block can be accurately calculated.

  Further, in the strip rigidity calculating step, it is preferable that a plurality of calculation functions for calculating the rigidity of the divided strips are created in advance based on the result of calculating the rigidity of a representative strip shape for each type of boundary condition. . Accordingly, the rigidity of the strip can be calculated by simpler calculation, and the rigidity of the block can be accurately calculated.

  In addition, the shape acquisition step, the division step, the strip rigidity calculation step, and the evaluation step are repeated a plurality of times, and after evaluating the overall rigidity of the plurality of blocks, the plurality of the plurality of blocks are evaluated. It is preferable to further include a block group evaluation step for evaluating the rigidity of a block group in which a plurality of the blocks are grouped based on the evaluation result of the overall rigidity of the block. Thereby, the rigidity which put together the some block can be evaluated.

  According to the tire simulation of the present invention, it is possible to obtain the effect that the rigidity of the block portion of the tire can be calculated with high accuracy while reducing the amount of calculation.

FIG. 1 is a perspective view of a tire. FIG. 2 is a meridional sectional view of the tire shown in FIG. FIG. 3 is a plan view showing a schematic configuration of the tread surface of the tire shown in FIG. 1. FIG. 4 is an explanatory diagram showing an analysis apparatus according to the present embodiment. FIG. 5 is a flowchart showing the procedure of the tire simulation method according to the present embodiment. FIG. 6 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 7 is an explanatory diagram showing an example of the correspondence used for calculating the rigidity of the strip. FIG. 8 is an explanatory diagram showing an example of the correspondence used for calculating the rigidity of the strip. FIG. 9 is an explanatory diagram showing an example of the correspondence used for calculating the rigidity of the strip. FIG. 10 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 11 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 12 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 13A is an explanatory diagram for explaining processing of the tire simulation method. FIG. 13B is a side view of FIG. 13A. FIG. 14 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 15 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 16 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 17 is an explanatory diagram for explaining processing of the tire simulation method. FIG. 18 is a perspective view showing a schematic configuration of a block of a tread portion of a tire used for measurement. FIG. 19A is a perspective view illustrating a schematic configuration of a block of a tread portion of a tire used for measurement. FIG. 19B is a top view of the block shown in FIG. 19A. FIG. 20A is a perspective view illustrating a schematic configuration of a block of a tread portion of a tire used for measurement. 20B is a top view of the block shown in FIG. 20A.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the content described in the following embodiment. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described in the following embodiments can be appropriately combined. In the present embodiment, the tire is described as an example of a pneumatic tire, but the application target of the present embodiment is a general tire and is not limited to a pneumatic tire.

  In the following description, the tire equator plane means a plane perpendicular to the tire rotation axis of the pneumatic tire and passing through the center of the tire width of the pneumatic tire. The tire width direction (width direction) means a direction parallel to the tire rotation axis, the inner side in the tire width direction is the side toward the tire equator in the tire width direction, and the outer side in the tire width direction is the tire equator in the tire width direction. Means the side away from The tire radial direction (radial direction) means a direction orthogonal to the pneumatic tire rotation axis, the tire radial inner side means the side toward the tire rotation axis in the tire radial direction, and the tire radial direction outer side means in the tire radial direction. It means the side away from the tire rotation axis. The tire circumferential direction (circumferential direction) means a circumferential direction centered on the tire rotation axis. Hereinafter, the pneumatic tire is referred to as a tire as necessary.

  FIG. 1 is a perspective view of a tire. FIG. 2 is a meridional sectional view of the tire shown in FIG. FIG. 3 is a plan view showing a schematic configuration of the tread surface of the tire shown in FIG. 1. 1 is a tire rotation axis, the Z axis is an axis orthogonal to the road surface on which the tire 1 contacts, and the X axis is an axis orthogonal to the Y axis and the Z axis. As shown in FIG. 1, the tire 1 is an annular structure that rotates about a tire rotation axis. As shown in FIG. 2, a carcass 2, a belt 3, a belt cover 4 and a bead core 5 appear on the meridional section of the tire 1. A cap tread 6 is disposed on the outer side in the tire radial direction of the tire 1 (on the side of the contact surface with the road surface). The tire 1 is a composite material structure in which rubber as a base material is reinforced by a reinforcing cord such as a carcass 2, a belt 3 or a belt cover 4 as a reinforcing material. A layer of a reinforcing cord made of a cord material such as a metal fiber or an organic fiber, such as the carcass 2, the belt 3, and the belt cover 4, is called a cord layer.

  The carcass 2 is a strength member that functions as a pressure vessel when the tire 1 is filled with gas (for example, air), and supports the load by the pressure (internal pressure) of the gas filled in the tire 1 and travels. It is designed to withstand dynamic loads inside. The belt 3 is a layer of reinforcing cords in which rubberized cords arranged between the cap tread 6 and the carcass 2 are bundled. In the case of a bias tire, it is called a breaker. In the radial tire, the belt 3 plays an important role as a shape retention and strength member.

  A belt cover 4 is disposed on the tread surface G side of the belt 3. The belt cover 4 is formed by arranging, for example, organic fiber materials in layers, and has a role as a protective layer for the belt 3 and a role as a reinforcing layer for the belt 3. The bead core 5 is a bundle of steel wires that supports the cord tension generated in the carcass 2 by internal pressure. The bead core 5 becomes a strength member of the tire 1 together with the carcass 2, the belt 3, the belt cover 4, and the tread. A side portion of the tire 1 is called a sidewall 8 and connects between the bead core 5 and the cap tread 6. Further, a shoulder portion Sh is provided between the cap tread 6 and the sidewall 8.

  As shown in FIGS. 2 and 3, four main grooves 7 a, 7 b, 7 c, 7 d extending in the tire circumferential direction are formed on the tread surface G side (tread surface) of the cap tread 6. This improves drainage during rainy weather. In addition, by forming the four main grooves 7a, 7b, 7c, 7d, the cap tread 6 has a land portion 11a on the outer side in the tire width direction from the main groove 7a, and the main groove 7a and the main groove 7b. A land portion 11b between the main groove 7b and the main groove 7c, a land portion 11d between the main groove 7c and the main groove 7d, and a land outside the main groove 7d in the tire width direction. Part 11e. The land portion 11c is formed at a position passing through the tire equator plane C. Moreover, the land part 11c has the decoration groove | channel 12 whose groove width is narrower than the main grooves 7a, 7b, 7c, and 7d, and a groove depth is small. Furthermore, the land portion 11b has a plurality of lug grooves 14 extending in the tire width direction and extending from the main groove 7a to the main groove 7b at regular intervals in the tire circumferential direction. With such a structure, the land portion 11b has a shape in which the blocks 16 surrounded by the main groove 7a, the main groove 7b, and the lug groove 14 are arranged in a plurality of rows in the tire circumferential direction. The land portion 11d also has a plurality of lug grooves 14 extending in the tire width direction and extending from the main groove 7c to the main groove 7d at regular intervals in the tire circumferential direction. With such a structure, the land portion 11d has a shape in which a plurality of blocks 16 surrounded by the main groove 7c, the main groove 7d, and the lug groove 14 are arranged in the tire circumferential direction. Thus, the tire 1 has the lug grooves 14 in the land portions 11b and 11d at regular intervals in the circumferential direction. For this reason, the tire 1 has a non-uniform shape in the tire circumferential direction, that is, a shape in which irregularities are formed in the tire circumferential direction. Further, the tire 1 alternately has lug grooves 14 and blocks 16 at regular intervals in the tire circumferential direction. With such a structure, the tire 1 has a shape in which the same shape is repeated for each pitch P in the tire circumferential direction. That is, the tire 1 has a shape of a certain angle corresponding to the pitch P around the tire rotation axis as a repeating unit, and a plurality of the tires 1 arranged in the circumferential direction of the shape corresponding to the pitch P.

  Next, an apparatus for executing the tire simulation method according to the present embodiment will be described. FIG. 4 is an explanatory diagram showing an analysis apparatus according to the present embodiment. The analysis device 50 is a computer. The analysis device 50 is a device that realizes the tire simulation method according to the present embodiment. As illustrated in FIG. 4, the analysis device 50 includes a processing unit 52 and a storage unit 54. The input / output device 51 is electrically connected to the analysis device 50, and information necessary for creating an analysis model, or an arithmetic expression and processing used for calculating rigidity are input via an input unit 57 provided therein. Programs, boundary conditions, and the like are input to the processing unit 52 and the storage unit 54. The analysis device 50 also displays various information such as calculation results and input results on the display means 55 of the input / output device 51. An analysis model (corresponding to a simulation model) is a model that can be numerically analyzed using a computer, and includes a mathematical model and a mathematical discretization model.

  An input device such as a keyboard and a mouse can be used for the input means 57. The storage unit 54 stores a computer program including a tire deformation analysis and a tire simulation method according to the present embodiment. The storage unit 54 stores parameter information 54a including information on various conditions used in the simulation method (function expressions, correspondence between various parameters and rigidity, application conditions, etc.). Here, the storage unit 54 is a hard disk device, a magneto-optical disk device, a non-volatile memory such as a flash memory (a storage medium that can be read only such as a CD-ROM), or a RAM (Random Access Memory). Such a volatile memory or a combination thereof can be used.

  The computer program may be capable of realizing various tire simulation methods in combination with a computer program already recorded in the computer system. Further, the computer program for realizing the function of the processing unit 52 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by the computer system and executed to deform the structure. Analysis and a tire simulation method according to the present embodiment may be executed. Here, the “computer system” includes hardware such as an OS (Operating System) and peripheral devices.

  The processing unit 52 includes a model creation unit 52a and an analysis unit 52b. The model creation unit 52a acquires the three-dimensional shape of the tire to be analyzed, creates an analysis model (tire model) based on the acquired shape, and stores it in the storage unit 54. For example, the model creation unit 52a creates an analysis model from CAD (Computer Aided Design) data of a tire to be analyzed.

  The analysis unit 52b calculates the rigidity of the block portion of the tire model (analysis model) created by the model creation unit 52a. The analysis unit 52b includes a block shape acquisition unit 53a, a block division unit 53b, a parameter acquisition unit 53c, a strip stiffness calculation unit 53d, and a block stiffness calculation unit 53e. The block shape acquisition unit 53 a acquires the shape of the block to be analyzed and stores it in the storage unit 54. The block shape acquisition unit 53a acquires the shape of the block by extracting a block (block model) from the tire model created by the model creation unit 52a. In this embodiment, the block is extracted from the tire model. However, the block may be directly acquired from CAD data of the shape of the block. In this embodiment, the block shape data is acquired as a three-dimensional shape of the block. However, as the shape of the block, a set of plane views and dimensions that uniquely determine the three-dimensional shape of the block may be acquired. Good.

  The block dividing unit 53b reads the shape of the block acquired by the block shape acquiring unit 53a and stored in the storage unit 54, cuts the read block in a direction in which a cut surface in a predetermined direction is formed, and forms a plurality of strips. To divide. The block division unit 53b stores a plurality of strips created by dividing a block in the storage unit 54.

  The parameter acquisition unit 53c analyzes a plurality of strips created by the block division unit 53b and stored in the storage unit 54, and acquires various parameters (cross-sectional shape, material parameters, etc.) of the created strip. That is, the parameter acquisition unit 53c acquires various parameters relating to the strip based on the various values set in the created strip and block. It should be noted that the strip dimension parameter can be calculated geometrically from the block shape data. The parameter acquisition unit 53c acquires parameters for all the strips created by the block division unit 53b. The parameter acquisition unit 53c stores the acquired parameters in the storage unit 54.

  The strip stiffness calculation unit 53d calculates the stiffness of the strip created by the block division unit 53b based on the parameter acquired by the parameter acquisition unit 53c and the parameter information 54a stored in the storage unit 54. The strip rigidity calculation unit 53d calculates the rigidity of all the strips constituting the block by repeating the rigidity calculation process for each strip. The strip rigidity calculation unit 53 d stores the calculated rigidity of each strip in the storage unit 54.

  The block stiffness calculator 53e calculates and evaluates the stiffness of the block based on the strip stiffness calculated by the strip stiffness calculator 53d. Specifically, the rigidity of the block is calculated by summing the rigidity of all the strips constituting the block. The block stiffness calculation unit 53e stores the calculated block stiffness in the storage unit 54.

  The processing unit 52 includes, for example, a memory and a CPU (Central Processing Unit). At the time of stiffness analysis, the processing unit 52 performs calculation by reading the computer program into a memory incorporated in the analysis unit 52b by the analysis unit 52b based on the analysis model, input data, and the like created by the model creation unit 52a. At that time, the processing unit 52 appropriately stores a numerical value in the middle of the calculation in the storage unit 54 and extracts the numerical value stored in the storage unit 54 to advance the calculation. The processing unit 52 may realize the function by dedicated hardware instead of the computer program.

  As the display means 55, a liquid crystal display device or the like can be used. In addition, since the simulation results, simulation conditions, and the like can be output to a recording medium such as paper by a printing machine provided as necessary, a printing machine may be used as the display unit 55. The storage unit 54 may be in another device (for example, a database server). For example, the analysis device 50 may access the processing unit 52 and the storage unit 54 by communication from a terminal device including the input / output device 51.

  Next, a simulation model creation method and a tire simulation method according to the present embodiment will be described with reference to FIGS. The tire simulation method according to this embodiment can be realized by the analysis device 50 described above. FIG. 5 is a flowchart showing the procedure of the tire simulation method according to the present embodiment. FIG. 6 is an explanatory diagram for explaining processing of the tire simulation method. 7 and 8 are explanatory diagrams showing examples of correspondences used for calculating the rigidity of the strips.

  First, the processing unit 52 of the analysis apparatus 50 shown in FIG. 4 creates a tire model by the model creation unit 52a. In addition, a tire model is a tire model which has a block part in a tread part. The processing unit 52 creates the tire model and the block in a three-dimensional shape. When the tire creation model is created by the model creation unit 52a, the processing unit 52 executes the processing in the analysis unit 52b.

  First, in step S12, the analysis unit 52b calculates block shape data calculated by the block shape acquisition unit 53a, that is, stiffness, and prepares block shape data to be evaluated. In the present embodiment, the block shape acquisition unit 53a specifies a target block from the tire model created by the model creation unit 52a, and prepares the block shape data by extracting the identified block from the tire model.

  After preparing the block shape data in step S12, the analyzing unit 52b divides the block into strips by the block dividing unit 53b in step S14. Specifically, as shown in FIG. 6, the analysis target block 60 is divided by cut surfaces 62 a, 62 b, 62 c, 62 d, and 62 e (hereinafter referred to as a cut surface 62 unless a cut surface is specified). Accordingly, the block 60 includes a strip 64a cut by the cut surface 62a and the cut surface 62b, a strip 64b cut by the cut surface 62b and the cut surface 62c, and a strip 64c cut by the cut surface 62c and the cut surface 62d. And a strip 64d cut by the cutting surface 62e. FIG. 6 shows only a part of the cut surface of the block 60, but the entire region of the block 60 is cut by the cut surface and divided into a plurality of strips. Here, the cut surface is a surface parallel to the protruding direction (height direction) of the block, that is, the radial direction of the tire. That is, it is a surface orthogonal to the tread surface composed of blocks and the like. The plurality of cut surfaces are parallel to each other. Further, the cut surface cuts the block 60 at regular intervals. By dividing the block 60 by such a plurality of cut surfaces, the strips 64a, 64b, 64c, and 64d (hereinafter referred to as the strips 64 if the strip is not particularly specified) are in the width direction (the direction orthogonal to the cut surface). ) Have the same length (width).

  Here, the block 60 of the present embodiment has a shape in which the outermost surface in the tire radial direction is a square, and the square of the cross section perpendicular to the tire radial direction increases toward the inner side in the tire radial direction. That is, the side surface is inclined with respect to the tire radial direction. Further, the cut surface 62 has an outermost surface in the tire radial direction of the block 60 inclined with respect to the square. For this reason, for example, in the strip 64c, the outermost surface 70 in the tire radial direction is trapezoidal, and the side surfaces 72 and 74 sandwiched between the two cut surfaces are inclined surfaces inclined with respect to the tire radial direction. .

  When the analysis unit 52b divides the block into strips in step S14, the parameter acquisition unit 53c acquires the cross-sectional shape / material parameters of the strip in step S16. That is, the parameter acquisition unit 53c of the analysis unit 52b acquires various parameters necessary for calculation of rigidity, such as the cross-sectional shape / material parameter of the strip 64 created in step S14. Note that the analysis unit 52b acquires or calculates various types of information from information on materials set at the time of tire model creation, information on dimensions, information on division conditions in the block division unit 53b, and the like. Further, the parameter acquisition unit 53c reads parameters corresponding to the acquired information from the parameter information 54a as necessary. In addition, as a cross-sectional shape, the width | variety of a strip, height, length, each surface shape etc. are illustrated. Examples of material parameters include strip elastic modulus, material composition ratio, and the like.

  After acquiring various conditions in step S16, the analysis unit 52b calculates the rigidity of the strip by the strip rigidity calculation unit 53d in step S18. Specifically, the strip stiffness calculation unit 53d identifies the stiffness corresponding to the cross-sectional shape and material parameters of the strip acquired in step S16 from the information stored in the parameter information 54a, and the identified stiffness is determined. The rigidity of the strip.

  Hereinafter, a method for calculating the rigidity of the strip will be described with reference to FIGS. 7 and 8. FIG. 7 is a table showing a correspondence relationship between the plurality of parameters and the rigidity, which is a summary of the results of calculating the rigidity with various combinations of the plurality of parameters. FIG. 8 is a graph showing the relationship between dimensional parameters and rigidity. In FIG. 8, the vertical axis represents rigidity and the horizontal axis represents dimension parameters. For example, as shown in FIG. 7, the parameter information 54a stores a table in which a plurality of parameters are associated with the rigidity corresponding to the combination of the parameters. The parameters in the table of FIG. 7 are strip cross-sectional shape and material parameters, such as strip width, height, length, surface shape, strip elastic modulus, material composition ratio, and the like. The strip rigidity calculation unit 53d compares the combination of the strip parameters acquired by the parameter acquisition unit 53c with the parameters in the table shown in FIG. Calculated as the stiffness of

  Here, when the strip parameter is a value between parameters associated with the table of the parameter information 54a, interpolation is performed based on the value of the adjacent parameter. That is, as shown in FIG. 8, there are two dimension parameters A and B associated with the table of the parameter information 54a, and the strip dimension parameter is C which is a value between A and B. In this case, interpolation approximation (linear approximation in FIG. 8) may be performed to calculate the rigidity. Thus, the rigidity can be calculated even when the parameters in the table and the strip parameters do not completely match. It should be noted that the parameters of the respective items in the table may have a certain range in numerical values. Thereby, the number of the relationship between the parameter to prepare and rigidity can be decreased.

  After calculating the rigidity in step S18, the analysis unit 52b determines whether all the strips have been calculated in step S20, that is, whether the rigidity of all the strips constituting the block has been calculated. If the analysis unit 52b determines that all the strips have not been calculated in step S20 (No), that is, there is a strip for which rigidity has not been calculated, the process proceeds to step S16. Thereafter, the analysis unit 52 identifies a strip for which rigidity has not been calculated from the strips created in step S14, and executes the processes of steps S16 and S18 for the strip.

  If the analysis unit 52b has calculated all the strips in step S20 (Yes), that is, if it is determined that the stiffness of all the strips has been calculated, the block stiffness calculation unit 53e calculates the stiffness for each strip as step S22. Calculate the stiffness of the entire block. After calculating the rigidity of the entire block, the analysis unit 52b ends this process. The processing unit 52 may display the calculation result on the display means 55 after calculating the rigidity of the entire block.

  The analysis device 50 can calculate the rigidity of the block by dividing the analysis target block into strips and calculating the rigidity of the strip having a simple shape. Thereby, the rigidity of the block shape of a complicated tire can be calculated by the total of the rigidity calculation using the strip parameters (for example, the dimension parameter of the strip shape and the elastic modulus of the material) divided into simple shapes. . Thereby, the calculation load can be reduced. In the present embodiment, only the rigidity is calculated, but the calculated rigidity may be further evaluated (conditions for which the rigidity is set, whether the criteria are satisfied, etc.).

  Further, in the present embodiment, since the rigidity of the strip is calculated using a function (calculation function) with the strip shape parameter as a variable, the rigidity of the strip can be obtained by simple calculation or simple processing (association, matching of conditions). Can be calculated. That is, according to this embodiment, the rigidity of the strip can be calculated with a smaller amount of calculation than when the rigidity of the strip is calculated using a numerical calculation method such as FEM. Since the block shape is divided into a plurality of strips, the rigidity of blocks having various shapes can be calculated based on the rigidity of the strips having a fixed pattern. As the function, as in the above embodiment, the input (parameter) and output (stiffness) can be discretely used in the form of a neural network or mathematical expression (arithmetic expression) in addition to the tabular form. Also, the strip stiffness calculation unit 53d calculates the stiffness using interpolation approximation as in the present embodiment, that is, if there is a strip parameter between the prepared parameters, the two parameters of the adjacent parameters are calculated. It is preferable to calculate the rigidity of the strip based on the rigidity.

  Moreover, it is preferable that the function used in the strip rigidity calculation unit 53d is created in advance based on the result of calculating the rigidity of a typical strip shape. By calculating the rigidity of representative shapes and preparing a function in which parameters and rigidity are associated with each other, the rigidity of strips having various shapes can be calculated. Note that the rigidity of a representative shape can be calculated by numerical calculation such as FEM. In addition, a representative strip shape may be determined by combining a plurality of parameters extracted from the range of assumed strip shape parameters, or determined from parameters by sampling including an experimental design method. Also good. In addition, a function of the relationship between a parameter and stiffness can be created by calculating the stiffness of the shape of the parameter by repeated calculation while changing the parameter.

  Here, when the function used in the strip rigidity calculation unit 53d is created in advance based on the result of calculating the rigidity of a typical strip shape, the shape parameter and the rigidity of the strip are associated with each other when the strip is associated with the rigidity. If the relationship is confirmed and the nonlinearity is strong, it is preferable to create a function by further calculating the parameter interval in detail. Thus, the accuracy can be improved by preparing the function. Here, FIG. 9 is an explanatory diagram showing an example of the correspondence used for calculating the rigidity of the strip. FIG. 9 is a graph showing the relationship between the dimension parameter and the rigidity. In FIG. 9, the vertical axis represents rigidity and the horizontal axis represents dimension parameters. For example, as shown in FIG. 9, when the relationship between the stiffness and the dimensional parameter is detected by the number of points of the sample 1, it is detected that there is a non-linear portion in which the change speed of the stiffness changes in the intermediate region of the dimensional parameter. In this case, by detecting the relationship between the dimension parameter of the nonlinear portion and the rigidity by the number of points of the sample 2, the function indicating the relationship between the dimension parameter and the rigidity can be made a more accurate function. Note that it is possible to determine whether it is non-linear based on the relationship between the set condition and the approximate line.

  Further, in the above embodiment, the rigidity of the strip is calculated based on the relationship between the strip parameters and the function prepared in advance, but may be calculated by numerical calculation such as a finite element method (FEM). . When calculating the rigidity of a strip by numerical calculation, the processing time increases due to the processing of dividing the strip into elements, etc., compared to the case of using a function, and the amount of calculation for calculating the rigidity of the strip increases. However, the calculation amount and the processing time can be reduced as compared with the case where the block is calculated as it is by numerical calculation. In addition to the finite element method, numerical methods such as a finite difference method (Finite Difference Method: FDM) and a boundary element method (BEM) can be used for the numerical calculation. Further, the most appropriate analysis method can be selected according to the boundary condition or the like, or a plurality of analysis methods can be used in combination. The finite element method is an analysis method suitable for structural analysis, and is particularly suitable for a structure such as a tire. When creating a block model based on the finite element method, the block shape obtaining unit 53a creates a block model by dividing a block specified by the CAD data into a plurality of finite elements. The block model includes a mathematical model and a mathematical discretization model.

  Here, the cut surface is not particularly limited as long as the block can be divided into strips. In addition, since a cut surface is a surface which divides | segments a block into a strip, the cut surface divided | segmented into each strip becomes a mutually parallel surface. That is, the cut surface forms a strip by cutting the block while moving in a direction orthogonal to the cut surface. As will be described later, when the strip is further divided, a cut surface having a different direction from the cut surface is provided. Here, the cut surface may be a surface that is orthogonal to the surface parallel to the tire circumferential direction and the tire width direction when the surface parallel to the tire radial direction, that is, the surface radially outside the block is regarded as a plane. preferable. Thereby, the structure of a block can be calculated appropriately. The cut surface is more preferably a surface orthogonal to the tire width direction or a surface orthogonal to the tire circumferential direction. By making the cut surface a surface orthogonal to the tire width direction, the rigidity in the tire circumferential direction of the block can be suitably evaluated, and by making the cut surface a surface orthogonal to the tire circumferential direction, the tire width of the block The rigidity in the direction can be suitably evaluated. This makes it possible to evaluate the rigidity in the direction in which the necessity is higher among the rigidity of the block, and it is possible to more appropriately evaluate the performance of the block.

  Here, when the block is deformed by shear deformation, the block dividing portion 53b preferably has a cut surface parallel to the shear direction. Here, FIG. 10 is an explanatory diagram for explaining processing of the tire simulation method. As shown in FIG. 10, when the shear direction is the direction indicated by the arrow 80, it is preferable that the cut surfaces 62 a, 62 b, 62 c, 62 d, and 62 e extend in the direction of the arrow 80. Thereby, the longitudinal direction of the strips 64a, 64b, 64c, and 64d created by being divided by the cut surface becomes a direction parallel to the shearing direction, and the rigidity in the shearing direction can be suitably calculated and evaluated by the strips. Thereby, shear rigidity important as block rigidity can be accurately evaluated.

  It is preferable that the block dividing unit 53b divides the strip so that the width of the strip is 10% or less of the representative size of the block. The block dividing unit 53b is more preferably divided at a width where the width of the strip is 5% or less of the representative size of the block, and more preferably at a width where the width is 1% or less. In this way, by making the width of the divided strips sufficiently smaller than the width of the block, the shape of the top surface of the strip can be regarded as a substantially rectangular shape, and the strip parameters of the function can be maintained while maintaining the accuracy of rigidity calculation. Can be simplified. In addition, the average of the value in both sides of a strip cut surface, or the dimension of the surface of one side of a strip cut surface can be used for the dimension parameter of a strip. Further, as in the present embodiment, the intervals between the cut surfaces are preferably equal intervals, that is, the widths of the strips are preferably the same. Thereby, the width of the strip shape calculated as the representative shape can be made one, and the representative shapes to be prepared can be reduced. Here, the representative size of the block is calculated on the basis of the length in the direction orthogonal to the cut surface of the block. Specifically, the length in the direction perpendicular to the cut surface of the block (the width of the block in the direction perpendicular to the shear direction when the cut surface is parallel to the shear direction) may be used as the representative size. Here, FIG. 11 is an explanatory diagram for explaining processing of the tire simulation method. As shown in FIG. 11, the cutting surface 81 is moved in the direction of the arrow 82 to divide the block 60 to calculate the rigidity of the block 60, and the cutting surface 83 is moved in the direction of the arrow 84 to divide the block 60. When the rigidity of the block 60 is calculated, that is, when the rigidity of the block is calculated in a plurality of directions (when the block is cut in different directions and the rigidity is calculated a plurality of times), the direction of the direction orthogonal to the cut surface of the block In addition to length, an average length based on other directions for calculating stiffness, or the smaller dimension can be used. When calculating the rigidity of a plurality of blocks at the same time, in addition to the length in the direction orthogonal to the cut surface of the block, the average value of the lengths based on other blocks or the smaller dimension can be used. . Moreover, since the width component can be a fixed value, the calculation efficiency can be improved. Moreover, it is preferable that the width | variety of a strip shall be 0.1 mm or more and 1 mm or less. By setting the width of the strip to the above width, the rigidity of the block can be calculated more accurately.

  The strip rigidity calculating unit 53d preferably includes at least the ratio of the height and the length of the strip cross section in the strip dimension parameter. Here, FIG. 12 is an explanatory diagram for explaining processing of the tire simulation method. Specifically, as shown in FIG. 12, the ratio between the height h and the length l of the strip 64 is preferably used as one of the parameters. Thus, by using the ratio of the length and height of the strip as a parameter, the relationship between the parameter and the rigidity becomes linear, and a highly accurate function can be created with a smaller number of samples.

  Further, when the block has a shape including an inclined portion inclined with respect to a plane parallel to the tire width direction, the strip rigidity calculating unit 53d calculates the rigidity when the strip is a portion obtained by dividing only the inclined portion. It is preferable to execute a process of multiplying a factor. FIG. 13A is an explanatory diagram for explaining processing of the tire simulation method, and FIG. 13B is a side view of FIG. 13A. For example, when the block has a shape including the inclined portion 90 as shown in FIG. 13A, the strip rigidity calculating unit 53d determines the parameter when calculating the rigidity of the strip (for example, the strip 94) obtained by dividing the inclined portion 90 by the cutting surface 91. It is preferable to further apply a coefficient to the rigidity calculated based on the function and the function. Thus, by multiplying the coefficient, the influence of the inclined portion can be accurately reflected, and the rigidity of the block can be calculated with higher accuracy. Here, since the inclined part does not come into direct contact with the road surface, the displacement is not given directly in the calculation of shear deformation of a general block, but the inclined part reflects the contribution to the block rigidity by calculating the rigidity of the strip. can do. Furthermore, the rigidity of the block can be calculated with higher accuracy by adjusting the rigidity of the inclined portion by applying a coefficient.

  Here, the coefficient is preferably calculated based on the height of the strip with respect to the height of the entire block. For example, as shown in FIG. 13B, the height of the strip (the strip having the tread surface) 92 in the region that is not the inclined portion (the height of the entire block) is a, and the strip 94 is a portion obtained by dividing only the inclined portion. When the height (maximum height of the strip 94, height up to the dotted line 95 in FIG. 13B) is b, the coefficient is preferably b / a. Thus, by setting the coefficient to a value based on the height, more specifically, a value proportional to the height, the rigidity of the strip of the inclined portion can be calculated with higher accuracy.

  When there are materials having different elastic moduli in the cross section of the strip, it is preferable that the block dividing portion 53b further divides at least a boundary having different elastic moduli as a cut surface. Here, FIG. 14 is an explanatory diagram for explaining the processing of the tire simulation method. For example, as shown in FIG. 14, when the region 104 and the region 106 of the strip 102 have different elastic moduli, it is preferable to calculate the rigidity by setting the region 104 as one strip and the region 106 as one strip. . In addition, the direction of the cut surface in this case can be various directions, for example, it is good also as a surface parallel to a tire width direction like this embodiment. As a result, when the block is made of a material with different elastic modulus, more specifically, the rigidity of the block is calculated with high accuracy even when there are multiple different elastic moduli in the height direction (tire radial direction). can do. As will be described later, the block dividing unit 53b may further divide the strip based on the cross-sectional shape after dividing based on the difference in material.

  The block dividing unit 53b further divides the strip in a direction orthogonal to the cut surface to obtain a divided strip, and the strip stiffness calculation unit 53d determines the rigidity of the divided strip for each divided strip based on the parameter of the dimension of the divided strip. It is preferable to calculate the rigidity of the strip from the calculated rigidity of the divided strip. Here, FIG. 15 is an explanatory diagram for explaining processing of the tire simulation method. Specifically, as shown in FIG. 15, the block dividing unit 53 b is configured such that when the cross-sectional shape of the strip 110 (the shape of the cut surface, the shape of the surface parallel to the cut surface) is composed of a plurality of irregularities, Based on the cross-sectional shape, the strip 110 is divided into a plurality of divided strips 120, 122, 124, 126, 128, and 130. In addition, the strip rigidity calculation unit 53d calculates the rigidity separately for each of the divided divided strips 120, 122, 124, 126, 128, and 130, and calculates the calculated divided strips 120, 122, 124, 126, 128, and 130. The rigidity of the strip 110 is calculated by adding the rigidity. The block dividing unit 53b divides the strip so that the divided strip has a shape corresponding to a typical strip whose rigidity has been calculated in advance. In the example shown in FIG. 15, the positions of the recesses having different depths of the grooves 111 indicated by the line (i) of the block 110 are cut by the cutting surface 112 to divide the strip in the horizontal direction of the strip. Further, a position to be a convex end portion (connecting portion with the groove bottom) indicated by the line (ii) is cut by the cut surface 114, and the cross section is divided in the vertical direction. As a result, the block 110 is divided into divided strips 120, 122, 124, 126, 128, and 130. As a result, each of the divided strips 120, 122, 124, 126, 128, and 130 has a quadrangular cross-sectional shape (shape of a surface parallel to the cut surface) (a trapezoid whose top surface and bottom surface are parallel). In this way, by dividing the strip and making the shape of the divided strip simple, it is possible to calculate strips with various cross-sectional shapes without increasing the number of parameters that define the shape of the strip (split strip). Can do.

  In addition, it is preferable that the strip rigidity calculation unit 53d calculates the rigidity of the divided strip by using a calculation function that outputs the stiffness using the shape parameter of the divided strip as a variable. More specifically, it is preferable to calculate the rigidity of the divided strip using the same calculation function as that of the strip. As a result, the rigidity of the divided strip can be easily calculated.

  Moreover, it is preferable that a separate calculation function is set for each divided strip for each boundary condition. Moreover, it is preferable that the strip rigidity calculation unit 53d creates a plurality of calculation functions for calculating the rigidity of the divided strips in advance based on the result of calculating the rigidity of the representative strip shape for each type of boundary condition. Here, FIG. 16 is an explanatory diagram for explaining processing of the tire simulation method. For example, among the divided strips 120, 122, 124, 126, 128, and 130 shown in FIG. 16, the areas 140a, 140b, and 140c configured by the divided strips 120, 122, and 124 are the same boundary condition (tread surface). The same calculation function is used as a divided strip with a region). The divided strips 120, 122, and 124 can calculate rigidity as one divided strip. In addition, the area 142 a configured by the divided strips 126 and the area 142 b configured by the divided strips 126 and the divided strips 128 have the same boundary condition (divided strips whose both ends are connected to the divided strips included in the area 140). The same calculation function is used. Note that the calculation functions used in the areas 140a, 140b, and 140c are different from the calculation functions used in the areas 142a and 142b. Further, the region 144 configured by the divided strips 130 uses a different calculation function from the calculation function used in the regions 140a, 140b, and 140c and the calculation function used in the regions 142a and 142b. Thus, by setting the calculation function for each different boundary condition, the block rigidity can be calculated with higher accuracy. In particular, by using a function of a condition that gives a shear displacement to the upper surface (one) and a function of a condition that does not give a shear displacement to the upper surface (two according to the boundary conditions in the present embodiment), higher accuracy is achieved. Can calculate the rigidity of the block. The boundary condition includes whether there is a block in an adjacent area or a ground contact surface (whether a displacement is given).

  Further, the processing unit 52 (the analyzing unit 52b) of the analyzing apparatus 50 includes the above-described step S12 (shape acquisition step), step S14 (dividing step), step S16 to step S20 (strip rigidity calculating step), step S22 (evaluation step) is repeated a plurality of times, and the overall rigidity of the blocks is evaluated for a plurality of blocks. Then, based on the evaluation result of the overall rigidity of the plurality of blocks, The rigidity may be evaluated (block group evaluation step). That is, the analysis device 50 may repeat the rigidity calculation processing for a plurality of blocks constituting the tire to calculate the rigidity of the entire tire or the block group. Thereby, the rigidity of not only a single block but also a block group composed of a plurality of blocks and the rigidity of the entire tire pattern can be calculated. Here, FIG. 17 is an explanatory diagram for explaining processing of the tire simulation method. In the tire 200 shown in FIG. 17, two blocks 202 are arranged at the center in the tire width direction (direction orthogonal to the tire circumferential direction in the figure), and two blocks 204 are arranged at both ends of the block 202 in the tire width direction. Has been. Further, the respective blocks 202 and 204 are arranged in a row in the tire circumferential direction. Here, in the block 204, a region 204c between the region 204a on the center side in the tire width direction and the adjacent region 204a is a bottom-up region. Further, a region 204b outside the region 204a of the block 204 in the tire width direction has a groove similar to that of the block 202. When the analysis device 50 calculates the rigidity in the tire circumferential direction with the tire circumferential direction as the shear direction, the tire width direction end area 224 including the area 220 c in the tire width direction including the block 202 and the area 204 c of the block 204. Calculates the rigidity for each block, and the area 222 including the area 204a and the area 204b of the block 204 and the area 222 between the area 220 and the area 224 calculates the rigidity by using a different function for each area having different boundary conditions. The stiffness is calculated by the method. Thus, by repeating the calculation of the rigidity of each block a plurality of times, the rigidity of the entire tire and the rigidity of the grounded block can be suitably calculated.

(Evaluation example)
Next, an evaluation example in which the tire simulation method of the present embodiment is executed will be described with reference to FIGS. 18 to 20B. Here, FIG. 18 is a perspective view showing a schematic configuration of a block of a tread portion of a tire used for measurement. FIG. 19A is a perspective view illustrating a schematic configuration of a block of a tread portion of a tire used for measurement. FIG. 19B is a top view of the block shown in FIG. 19A. FIG. 20A is a perspective view illustrating a schematic configuration of a block of a tread portion of a tire used for measurement. 20B is a top view of the block shown in FIG. 20A.

  First, the analysis by the simulation method of the present embodiment was performed on the block 250 shown in FIG. Here, the block 250 has a trapezoidal shape in the XZ plane, and the trapezoidal shape extends in the Y direction. Further, the analysis was performed on the assumption that the block 250 is shear-deformed in the direction of the arrow 254. In this evaluation example, the rigidity was calculated for each of the case where the coefficient was not multiplied when calculating the rigidity of the strip including only the inclined portion and the case where the coefficient was multiplied. As the coefficient, a value proportional to the height was used. For comparison, the rigidity was also calculated by analysis using FEM. In the analysis using FEM, the analysis was performed by dividing the block 250 into a plurality of elements 252 as shown in the mesh of FIG.

  As a result of the analysis, the rigidity calculated without multiplying the coefficient when calculating the rigidity of the strip including only the inclined portion was 11.54, and the rigidity calculated by multiplying the coefficient was 10.69. The stiffness calculated by analysis with FEM was 10.47. Therefore, based on the stiffness calculated by analysis with FEM, the stiffness error calculated without multiplying the coefficient was 10.2%, and the stiffness error calculated by multiplying the coefficient was 2.1%. From the above, it can be seen that the rigidity can be calculated with higher accuracy by multiplying the coefficient when calculating the rigidity of the strip having only the inclined surface.

  Next, analysis by the simulation method of the present embodiment was performed with the block 260 shown in FIGS. 19A and 19B as an analysis target. Here, the block 260 has a shape in which the height in the Z direction is constant and the shape of the XY plane is a quadrangle. In addition, the analysis was performed on the assumption that the block 260 is shear-deformed in the direction of the arrow 264. The block 260 has a width of 23 mm in the direction orthogonal to the arrow 264. In this evaluation example, the block 260 was divided at intervals of 0.1 mm by a cut surface 265 parallel to the arrow 264 to create a strip, and the rigidity was calculated. For comparison, the rigidity was also calculated by analysis using FEM. In the analysis using FEM, the analysis was performed by dividing the block 260 into a plurality of elements 262 as shown in the mesh of FIG. 19A.

  As a result of the analysis, the stiffness calculated by the analysis by the simulation method of the present embodiment was 47.18, and the stiffness calculated by the analysis by FEM was 48.84. As described above, the error between the calculation result of the present embodiment and the calculation result of FEM is −3.4% (the rigidity of the present embodiment is 3.4% lower), and a substantially similar calculation result is obtained. Can do. If the analysis work time in the FEM is 100 (model creation time is 70, calculation time is 30), the analysis work time in this embodiment is 8 (model creation time is 5 and calculation time is 3). there were.

  Next, analysis by the simulation method of the present embodiment was performed with the block 270 illustrated in FIGS. 20A and 20B as an analysis target. Here, the block 270 has a shape in which the height in the Z direction is constant and the shape of the XY plane is a quadrangle. Further, the analysis was performed on the assumption that the block 270 is shear-deformed in the direction of the arrow 274. The block 270 has a width of 30 mm in the direction orthogonal to the arrow 274. In this evaluation example, the block 270 was divided at intervals of 0.1 mm by a cut surface 275 parallel to the arrow 274 to create strips, and the rigidity was calculated. For comparison, the rigidity was also calculated by analysis using FEM. In the analysis using FEM, the analysis was performed by dividing the block 270 into a plurality of elements 272 as shown in the mesh of FIG. 20A.

  As a result of the analysis, the stiffness calculated by the analysis by the simulation method of the present embodiment was 73.27, and the stiffness calculated by the analysis by FEM was 74.97. As described above, the error between the calculation result of this embodiment and the calculation result of FEM is −2.3% (the rigidity of the present embodiment is 2.3% lower), and a substantially similar calculation result is obtained. Can do. 20A and 20B, if the analysis work time in the FEM is 100 (model creation time is 70, calculation time is 30), the analysis work time of this embodiment is 8 (model creation time is 5, calculation time is 3). From the above, it can be seen that the rigidity can be calculated with the same accuracy as in the case where the block is integrated and analyzed by FEM while reducing the working time.

DESCRIPTION OF SYMBOLS 1 Tire 50 Analysis apparatus 51 Input / output device 53 Processing part 53a Block shape acquisition part 53b Block division part 53c Parameter acquisition part 53d Strip rigidity calculation part 53e Block rigidity calculation part 54 Storage part 54a Parameter information 55 Display means 60 Block 62a, 62b Cutting Surface 64 Strip 72, 74 Side

Claims (11)

A shape acquisition step for acquiring the shape of a block constituting the tire tread to be calculated by a computer;
A dividing step of dividing the block into strips by a computer;
For each of the divided strips by a computer, a strip stiffness calculation step for calculating the stiffness of the strip based on the dimension parameter of the strip,
By the computer, an evaluation step of summing the rigidity of the plurality of strips constituting the block and evaluating the overall rigidity of the block;
Have
In the dividing step, a cutting surface that divides the block into strips is a surface orthogonal to the tire width direction or a surface orthogonal to the tire circumferential direction,
The cutting planes are parallel to each other;
The strip rigidity calculating step includes the shape parameter of the strip and the size of the strip stored in advance when there is a shape parameter of the target strip in the relationship between the strip dimension parameter stored in advance and the rigidity of the strip. Based on the relationship between the parameters and the rigidity of the strip, the rigidity of the strip is calculated,
If there is no shape parameter of the target strip in the relationship between the strip dimension parameter stored in advance and the rigidity of the strip, approximate interpolation is performed using a calculation function that outputs the stiffness using the shape parameter of the strip as a variable. , Calculate the rigidity of the strip ,
The tire calculation method according to claim 1, wherein the calculation function is created in advance based on a result of calculating a stiffness of a representative strip shape by numerical analysis .   2. The tire simulation method according to claim 1, wherein the strip stiffness calculation step calculates the stiffness of the strip based on a dimension parameter of the strip and an elastic modulus of the material. The block is deformed by shear deformation,
3. The tire simulation method according to claim 1, wherein in the dividing step, a cut surface that divides the block into strips is a plane parallel to a shear direction. 4. In the dividing step, the width of the strip is divided by a width that is equal to or less than 10% of a representative size based on the length of the block in a direction orthogonal to a cutting plane that divides the block into strips. The tire simulation method according to any one of claims 1 to 3 . The strip stiffness calculation step, the parameters of the dimensions of the strip, the simulation method of tire according to claim 1, any one of 4, characterized in that it comprises the ratio of the height and length of at least a strip section. The block has a shape including an inclined portion inclined with respect to a plane parallel to the tire width direction,
The strip stiffness calculation step, if the strip is a part obtained by dividing only the inclined portion, claim 1, characterized in that performing the process of applying the coefficients to the calculated stiffness in any one of 5 The tire simulation method described. The dividing step, if there is a material of different modulus strips in cross-section, divided by at least an elastic modulus different boundaries, to any one of claims 1 to 6, characterized in that the separate strip The tire simulation method described. The dividing step further divides the strip into a strip by further dividing the strip in a direction perpendicular to a cut surface that divides the block into strips,
The strip rigidity calculating step calculates, for each of the divided strips, the rigidity of the divided strip based on the parameter of the dimension of the divided strip, and calculates the rigidity of the strip from the calculated rigidity of the divided strip. The tire simulation method according to any one of claims 1 to 7 . 9. The tire simulation method according to claim 8 , wherein the strip rigidity calculating step calculates the rigidity of the divided strip by using a calculation function that outputs a stiffness using a shape parameter of the divided strip as a variable. The strip rigidity calculating step is characterized in that a plurality of calculation functions for calculating the rigidity of the divided strips are created in advance based on the result of calculating the rigidity of a representative strip shape for each type of boundary condition. The tire simulation method according to claim 9 . The shape acquisition step, the division step, the strip rigidity calculation step, and the evaluation step are repeated a plurality of times, and after evaluating the overall rigidity of the block for the plurality of blocks,
Based on the evaluation results of the overall stiffness of the plurality of the blocks, any of claims 1 to 10, characterized by further comprising a block group evaluation step of evaluating the rigidity of the block group summarizing a plurality of said blocks The tire simulation method according to one item.