JP2012006523A - Simulation model creating method, simulation method, simulation model creating device and simulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an increase in calculation time in tire simulation.SOLUTION: A computer creates a first tire model ununiform in a circumferential direction based on a pneumatic tire to be evaluated, and a second tire model actually ununiform in the circumferential direction based on the pneumatic tire to be evaluated (step S12). The computer executes analysis of contact of the second tire model to obtain displacement of joints of the second tire model (step S14). The computer imparts, to the first tire model, rotation information indicating the change in joints in time which is obtained by converting the circumferential position of the joints of the second tire model into time to obtain the rolling shape of the first tire model (steps S16, S18). The computer creates a spatial model in which a region including a region contacting like a contacting shape is divided into a plurality of elements (step S20).

Description

  The present invention relates to a method for creating a simulation model used for tire analysis using a computer, a simulation method using the created simulation model, and an apparatus therefor.

  A method for evaluating various performances of a tire by analysis using a computer and designing a tire and further a vehicle on which the tire is mounted based on the performance has been proposed and put into practical use. For example, Patent Document 1 describes a simulation method for analyzing the behavior of an assembly of a tire and a wheel by a numerical analysis method such as a finite element method. Patent Document 2 describes a simulation method for analyzing the noise performance of a tire.

JP 2007-83925 A JP 2009-161115 A

  In order to evaluate the performance of the tire, it is necessary to calculate the shape of the tire at each time corresponding to the conditions as a simulation model. For example, the simulation methods described in Patent Document 1 and Patent Document 2 perform an operation of rotating the tire while the tire model is in contact with the road surface model. That is, in these simulation methods, deformation calculation is repeatedly performed to calculate the tire shape. However, like the simulation methods described in Patent Document 1 and Patent Document 2, the tire model and the road surface model are relatively rotated, and the tire shape at each time of the rolling tire model is calculated repeatedly. And the calculation for calculating the shape of the tire increases. When the amount of calculation increases, the analysis takes a long time and the load on the computer increases. In particular, in the case of a pneumatic tire in which the meridional cross-sectional shape changes in the circumferential direction due to the formation of lug grooves or the like, the increase in calculation amount is significant.

  The present invention has been made in view of the above, and an object of the present invention is to provide a simulation model creation method, a simulation method, a simulation model creation device, and a simulation device that can suppress an increase in time required for calculation.

  In order to solve the above-described problems and achieve the object, a simulation model creation method according to the present invention includes a first tire model in which a computer is uneven in a circumferential direction based on a pneumatic tire to be evaluated, and the evaluation object. A first model creating step for creating a second tire model substantially uniform in the circumferential direction based on the pneumatic tire, a wheel model, and a road surface model; and the computer performs a ground contact analysis of the second tire model. And a time of the node obtained by converting the circumferential position of the node of the second tire model into time by the ground contact analysis unit that executes and calculates the displacement of the node of the second tire model. Rotation information representing a change with respect to the relative position relationship between the nodes of the first tire model and the nodes of the second tire model. In addition, a tire rolling shape creation step for obtaining a rolling shape of the first tire model by applying to the first tire model, and a rolling shape obtained by the computer in the tire rolling shape creation step. And a second model creating step of creating a spatial model in which a region including a region in contact with is divided into a plurality of elements.

  As a desirable mode of the present invention, in the tire rolling shape creation step, it is preferable that the computer obtains the rotation information by performing a rotation calculation on information representing a position of a node of the first tire model.

  As a desirable mode of the present invention, in the tire rolling shape creation step, the computer preferably obtains the rotation information by interpolating information between nodes adjacent in the circumferential direction of the first tire model.

  As a desirable mode of the present invention, in the first model creation step, it is preferable that the computer provides an extended region outside the second tire model.

  As a desirable mode of the present invention, in the second model creation step, the computer is formed around the rolling shape, and a first element region in which the structure of the element changes according to the time change of the rolling shape; It is preferable to create the spatial model including a second element region formed on the outer periphery of the first element region and having an element structure that does not change.

  As a preferred aspect of the present invention, in the second model creation step, the computer converts an analysis model of at least a part of a vehicle on which the pneumatic tire to be evaluated is mounted, and uses the analysis model and the rolling shape. It is preferable to create a spatial model by dividing an area including a contact area into a plurality of elements.

  In order to solve the above-described problems and achieve the object, a simulation method according to the present invention is characterized in that the computer performs fluid analysis using the spatial model obtained by the simulation model creation method. To do.

  In order to solve the above-described problems and achieve the object, a simulation model creation device according to the present invention includes a first tire model that is non-uniform in a circumferential direction based on a pneumatic tire to be evaluated, and a pneumatic to be evaluated. Performing a first analysis model creation unit that creates a second tire model that is substantially circumferentially uniform based on a tire, a wheel model, and a road surface model; and a contact analysis of the second tire model, A ground contact analysis unit for obtaining a displacement of a node of the two tire model, and rotation information representing a change of the node with respect to time obtained by converting a circumferential position of the node of the second tire model into time. The first tire model is given to the first tire model by using a relative positional relationship between the nodes of the one tire model and the nodes of the second tire model. An analysis result conversion unit for obtaining a rolling shape of the ear model; a second model creation unit for creating a spatial model in which a region including a region in contact with the rolling shape obtained by the analysis result conversion unit is divided into a plurality of elements; It is characterized by including.

  As a desirable mode of the present invention, it is preferable that the analysis result conversion unit obtains the rotation information by performing a rotation calculation on information representing a position of a node of the first tire model.

  As a desirable aspect of the present invention, it is preferable that the analysis result conversion unit obtains the rotation information by interpolating information between nodes adjacent in the circumferential direction of the first tire model.

  As a desirable aspect of the present invention, it is preferable that the analysis result conversion unit is provided with an extended region outside the second tire model.

  As a desirable mode of the present invention, the second model creation unit is formed around the rolling shape, and the first element region in which the structure of the element changes according to the time change of the rolling shape, and the first It is preferable to create the spatial model including a second element region that is formed on the outer periphery of the element region and does not change the element structure.

  As a desirable mode of the present invention, the second model creation unit converts an analysis model of at least a part of a vehicle on which the pneumatic tire to be evaluated is mounted, and an area in contact with the analysis model and the rolling shape. It is preferable to create a spatial model by dividing a region to be included into a plurality of elements.

  In order to solve the above-described problems and achieve the object, a simulation apparatus according to the present invention is characterized in that a fluid analysis is performed using the spatial model obtained by the simulation model creation apparatus.

  The present invention can suppress an increase in time required for 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 / evaluation apparatus according to this embodiment. FIG. 5 is a flowchart showing the procedure of the tire simulation method according to the present embodiment. FIG. 6A is a side view of an example of the first tire model. FIG. 6-2 is a partially enlarged view showing an example of the first tire model shown in FIG. 6-1. FIG. 7-1 is a side view showing an example of the second tire model. FIG. 7-2 is a partially enlarged view showing an example of the second tire model shown in FIG. 7-1. FIG. 8 is a schematic diagram for explaining the correspondence between the nodes of the first tire model and the nodes of the second tire model. FIG. 9 is an explanatory diagram of the relative positional relationship between the nodes of the first tire model and the nodes of the second tire model. FIG. 10A is an explanatory diagram illustrating an example in which an extended region is provided outside the second tire model. FIG. 10-2 is an explanatory diagram illustrating an example in which an extended region is provided outside the second tire model. FIG. 10-3 is an explanatory diagram illustrating an example in which an extended region is provided outside the second tire model. FIG. 11A is a diagram illustrating an example in which the position of the corresponding point is calculated based on the ground contact analysis. FIG. 11B is a diagram illustrating an example in which the position of the corresponding point is converted into a function of time. FIG. 12 is a perspective view showing a schematic configuration of a model around the tire. FIG. 13 is an explanatory diagram showing another example in which the circumferential positions of the nodes existing on the surface of the first tire model are converted into time. FIG. 14 is a schematic configuration diagram illustrating another example of a fluid analysis model. 15A is an enlarged view showing a part of the fluid analysis model shown in FIG. 15-2 is an enlarged view showing a part of the fluid analysis model shown in FIG. 14 in an enlarged manner. FIG. 16 is a perspective view illustrating a schematic configuration of a fluid analysis model according to another example of the present embodiment.

  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 referred to as 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, a simulation model creation method and a device that executes the simulation method according to the present embodiment will be described.

  FIG. 4 is an explanatory diagram showing an analysis / evaluation apparatus according to this embodiment. The analysis / evaluation apparatus 50 is a computer. The analysis / evaluation device 50 is a simulation model creation device and a simulation device, and is a device that realizes the simulation model creation method and simulation method according to the present embodiment. As shown in FIG. 4, the analysis / evaluation apparatus 50 includes a processing unit 52 and a storage unit 54. The analysis / evaluation apparatus 50 is electrically connected to an input / output device 51. Information necessary for creating an analysis model, or a boundary in grounding analysis or fluid analysis, is input via an input unit 53 provided therein. Conditions and the like are input to the processing unit 52 and the storage unit 54. In addition, the analysis / evaluation apparatus 50 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 53. The storage unit 54 stores a computer program including a tire deformation analysis and a tire simulation method according to the present embodiment. 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 first model creation unit 52a, a ground contact analysis unit 52b, an analysis result conversion unit 52c, a second model creation unit 52d, a fluid analysis unit 52e, and an evaluation unit 52f. The first model creation unit 52 a creates an analysis model for use in grounding analysis and stores it in the storage unit 54. The first model creation unit 52a creates a first tire model, a second tire model, a road surface model, and a wheel model as analysis models. The first model creation unit 52a also sets boundary conditions. These analysis models and boundary conditions are created and set based on information input from the input means 53 by the user of the analysis / evaluation apparatus 50.

  The ground analysis unit 52b reads the analysis model created by the first model creation unit 52a from the storage unit 54, and executes the ground analysis under the set conditions. The analysis result conversion unit 52c extracts corresponding points (corresponding nodes) from the tire shape obtained by the ground contact analysis unit 52b performing the ground contact analysis. Then, the analysis result conversion unit 52c converts the result of the ground contact analysis into time-series data of the tire shape in the rolling state using the position of the corresponding point, the information on the rotation angle, and the speed information.

  The second model creation unit 52d uses the time series data of the tire shape in the rolling state converted by the analysis result conversion unit 52c to make an analysis model of the space around the tire shape at each time. In the present embodiment, an analysis model (space model) in which a fluid mesh is created in a space around the tire shape is created. The fluid analysis unit 52e performs fluid analysis of the spatial model created by the second model creation unit 52d under the set conditions. The conditions used for the analysis (fluid analysis and acoustic analysis) performed by the fluid analysis unit 52e are also created and set based on the numerical values input from the input means 53 by the user. The evaluation unit 52f evaluates the performance of the tire based on the result analyzed by the fluid analysis unit 52e. Evaluation targets include air flow around the tire, tire air resistance, tire acoustic characteristics, tire noise, and the like.

  The processing unit 52 includes, for example, a memory and a CPU (Central Processing Unit). At the time of contact analysis and fluid analysis, the processing unit 52 incorporates the computer program into the processing unit 52 based on the analysis model and input data created by the first model creation unit 52a and the second model creation unit 52d. Read into memory and calculate. 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 / evaluation apparatus 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 this embodiment will be described. The tire simulation method according to the present embodiment can be realized by the analysis / evaluation apparatus 50 described above.

  FIG. 5 is a flowchart showing the procedure of the tire simulation method according to the present embodiment. The tire simulation method according to the present embodiment includes a simulation model creation method according to the present embodiment. FIG. 6A is a side view of an example of the first tire model. FIG. 6-2 is a partially enlarged view showing an example of the first tire model shown in FIG. 6-1. FIG. 7-1 is a side view showing an example of the second tire model. FIG. 7-2 is a partially enlarged view showing an example of the second tire model shown in FIG. 7-1.

  In executing the simulation method according to the present embodiment, in step S12, the first model creation unit 52a of the analysis / evaluation apparatus 50 shown in FIG. 4 includes the first tire model 60 (FIG. 6-1) and the evaluation object. A second tire model 80 (FIG. 7-1), a wheel model 64 (FIG. 7-1), and a road surface model 66 (FIG. 7-1) created based on the pneumatic tire are prepared (first). Model creation step). The first tire model 60 and the second tire model 80 are created based on the evaluation target tire. The wheel model 64 is attached to at least the second tire model 80. The road surface model 66 is grounded by the second tire model 80 in a grounding analysis described later. These are all analytical models. The first model creation unit 52a also sets boundary conditions used for analysis.

  The first tire model 60 used in the present embodiment has the same shape as the tire shown in FIGS. 1 to 3 and has a shape in which lug grooves extending in the tire width direction are formed at regular intervals in the tire circumferential direction. is there. The first tire model 60 has a shape in which a plurality of blocks 62 are arranged in a row in the tire circumferential direction. That is, the first tire model 60 is an analytical model having a non-uniform shape in the circumferential direction. The non-uniform shape in the circumferential direction means that at least a part of the meridional section of the first tire model 60 is different in the circumferential direction.

  The second tire model 80 is an analysis model having a shape that is substantially uniform in the circumferential direction, preferably uniform in the circumferential direction. The uniform shape in the circumferential direction means that any meridional section of the second tire model 80 has the same shape in the circumferential direction. For this reason, the 2nd tire model 80 has the circumferential direction groove | channel extended toward the circumferential direction, when there is no groove | channel on the surface or has a groove | channel, and does not have a lug groove | channel. In the present embodiment, the second tire model 80 does not have a groove. When the 2nd tire model 80 has a circumferential groove | channel, the line | wire which connected the width direction center of the circumferential groove | channel is parallel to an equatorial plane.

  The second tire model 80 is a model used for performing a ground contact analysis using a numerical analysis method such as a finite element method or a finite difference method. For example, in this embodiment, since the finite element method (Finite Element Method: FEM) is used for the ground contact analysis of the second tire model 80, the second tire model 80 is created based on the finite element method. The analysis method applicable to the grounding analysis according to the present embodiment is not limited to the finite element method, and a finite difference method (FDM), a boundary element method (BEM), or the like can also be used. 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. Since the finite element method is an analysis method suitable for structural analysis, it can be suitably applied particularly to a structure such as a tire.

  In step S12, the first model creation unit 52a divides the tire that is the annular structure (evaluation target tire) into a plurality of finite elements, as shown in FIGS. 6-1 and 7-1. A first tire model 60 and a second tire model 80 are created. Each of the plurality of elements has a plurality of nodes. For example, the first model creation unit 52a creates the first tire model 60 and the second tire model 80 by dividing the CAD data of the tire to be evaluated into a plurality of finite elements. In the present embodiment, the first tire model 60 and the second tire model 80 are three-dimensional shape analysis models.

  The elements of the first tire model 60 and the second tire model 80 are, for example, solid elements such as tetrahedral solid elements, pentahedral solid elements, and hexahedral solid elements in a three-dimensional body, and shells such as triangular shell elements and rectangular shell elements. It is desirable to use elements that can be handled by computers, such as elements and surface elements. In the process of analysis, the elements divided in this way are identified one by one using three-dimensional coordinates and cylindrical coordinates in the three-dimensional model. The wheel model 64 may be created in the same manner as the second tire model 80, or may be created as a rigid model. Further, the road surface model 66 may be created in the same manner as the second tire model 80 or may be created as a surface model.

  When the processing unit 52 creates the first tire model 60, the second tire model 80, the wheel model 64, and the road surface model 66 in step S12, the processing unit 52 stores them in the storage unit 54 and proceeds to step S14. In step S14, the ground contact analysis unit 52b included in the processing unit 52 of the analysis / evaluation apparatus 50 performs the ground contact analysis of the second tire model 80 created in step S12 (ground contact analysis step). In the present embodiment, the second tire model 80 is attached to the wheel model 64 prior to the ground contact analysis.

  The ground analysis is executed based on the set analysis conditions. The ground contact analysis is to analyze at least the state of deformation or strain of the second tire model 80 in a dynamic or static contact state between the second tire model 80 and a plane or curved surface. In this embodiment, a load is applied from the rotation axis of the second tire model 80 in a state where the second tire model 80 is in contact with the object to be grounded (road surface model 66 in the present embodiment). The state of strain is analyzed. The analysis conditions are input to the analysis / evaluation apparatus 50 via the input means 53 of the input / output device 51 shown in FIG. 2 and stored in the storage unit 54, for example. When the analysis conditions are set, the ground contact analysis unit 52b brings the second tire model 80 into contact with the road surface model 66 and loads the second tire model 80 to perform a ground contact analysis. Find the displacement of the node you have. Then, the ground analysis unit 52b stores the obtained displacement in the storage unit 54. The processing unit 52 proceeds to step S16 after executing the grounding analysis in step S14.

  In step S <b> 16, the analysis result conversion unit 52 c included in the processing unit 52 of the analysis / evaluation apparatus 50 uses the relative positional relationship between the nodes of the first tire model 60 and the nodes of the second tire model 80 as rotation information. Give. The rotation information is a change (displacement) with respect to time of the node obtained by converting the circumferential position of the node (represented by the central angle about the rotation axis) of the second tire model 80 into time. Is information. The rotation information may be obtained from the displacement and position (coordinates) of the nodes of the second tire model 80, or the first tire model 60 obtained from the displacement of the nodes of the second tire model 80 obtained by the ground contact analysis. You may obtain | require from the displacement and position (coordinate) of the node which exists in the surface of this.

  FIG. 8 is a schematic diagram for explaining the correspondence between the nodes of the first tire model and the nodes of the second tire model. FIG. 9 is an explanatory diagram of the relative positional relationship between the nodes of the first tire model and the nodes of the second tire model. FIGS. 10-1 to 10-3 are explanatory diagrams illustrating an example in which an extended region is provided outside the second tire model. FIG. 11A is a diagram illustrating an example in which the position of the corresponding point is calculated based on the ground contact analysis. FIG. 11B is a diagram illustrating an example in which the position of the corresponding point is converted into a function of time. When the rotation information is given to the first tire model 60, it is necessary to grasp the relative positional relationship between the nodes of the first tire model 60 and the nodes of the second tire model 80. As shown in FIG. 9, the position of the node (white circle in FIG. 9) of the first tire model 60 corresponds to which position (white circle in FIG. 9) corresponds to the second tire model 80. As shown in FIG. 5, it is to know which element 82 of the second tire model 80 the surface node 61 of the first tire model 60 belongs to.

  In the present embodiment, the first tire model 60 and the second tire model 80 are such that the former has a non-uniform shape in the circumferential direction and the latter has a uniform shape in the circumferential direction. It is. For this reason, the 1st tire model 60 and the 2nd tire model 80 can be piled up. When both are superimposed, the node 61 on the surface of the first tire model 60 and the element 82 of the second tire model 80 to which the node 61 belongs are the coordinate system (XYZ coordinate system or cylindrical coordinate system, etc.) of both tire models. ) Can be grasped. The processing unit 52 determines which element 82 of the second tire model 80 each node 61 on the surface of the first tire model 60 belongs to when the first tire model 60 and the second tire model 80 are created. The relationship between the two is stored in the storage unit 54.

  When the node 61 on the surface of the first tire model 60 belongs to the element 82 of the second tire model 80, the displacement of the node 61 is, for example, the shape function of the element 82 composed of a plurality of nodes 81A, 81B, 81C, 81D. Can be obtained from Since the first tire model 60 has a groove, the nodes present on the groove wall and the groove bottom of the first tire model 60 are present inside the second tire model 80. In this case, the nodes existing on the groove wall and the groove bottom are hexahedral elements, tetrahedral elements, and the like of the second tire model 80. As in the above-described example, the displacement of the nodes is obtained from the shape function of the element. be able to. The method for obtaining the displacement of the node 61 is not limited to the shape function. The analysis result conversion unit 52c obtains the displacement of the node existing on the surface of the first tire model 60 from the information (displacement) of the node included in the second tire model 80, and stores it in the storage unit 54 by the method described above.

  The displacement of the nodes existing on the surface of the first tire model 60 is obtained by the method described above. In obtaining the rotation information (more specifically, the rotation information of the first tire model 60), the analysis result conversion unit 52c extracts the position of each corresponding node of the first tire model 60. Specifically, the analysis result conversion unit 52c calculates the relationship between the tire circumferential direction angle and coordinates of each node on the tire surface of the first tire model 60 at the time of ground contact. Thereafter, the analysis result conversion unit 52c extracts information on nodes adjacent in the circumferential direction as corresponding point information from the relationship between the calculated angles and coordinates of the nodes in the circumferential direction.

  In other words, in the present embodiment, the analysis result conversion unit 52c identifies one node in the block 62 shown in FIGS. 6-1 and 6-2 as the corresponding node 70, and the corresponding node 70 in the meridional section of each block 62. As the corresponding nodes 70 of the respective blocks 62, the nodes existing at the same position are extracted for one round in the circumferential direction of the first tire model 60. Then, the analysis result conversion unit 52c extracts the relationship between the position of each corresponding node in the circumferential direction (represented by the central angle around the rotation axis) and the coordinates. Here, in FIG. 6B, in order to clarify the relationship between the block 62 and the corresponding node 70, the corresponding node 70 is shown inside the block 62. However, the corresponding node 70 is a point on the surface of the block 62. (Node).

  As described above, when the relationship between the circumferential position and the coordinates of the plurality of corresponding nodes extending in the circumferential direction is extracted, the radial coordinate (displacement in the radial direction) and the circumferential direction are extracted as shown in FIG. The relationship with the position (that is, the central angle around the rotation axis) can be obtained. In FIG. 11A, the vertical axis is the radial coordinate [mm], and the horizontal axis is the angle [°]. This angle is a central angle around the rotation axis and corresponds to the circumferential position of the corresponding node. Angles 0 ° and 360 ° correspond to positions farthest from the road surface (in FIG. 6-1, the position in the 12 o'clock direction of the clock), and angles 180 ° are closest to the road surface (in FIG. 6A). , The position of the watch in the 6 o'clock direction). Further, the radial coordinate is a coordinate of an axis (Z axis in FIG. 1) orthogonal to the contact target surface of the first tire model 60, and the rotation axis (Y axis) of the first tire model 60 is a reference (0 mm). did. From the relationship shown in FIG. 11A, it is possible to determine in which circumferential position the corresponding node 70 of the block 62 of the first tire model 60 is located. In FIG. 11A, the relationship between the radial coordinate and the circumferential position is shown. Similarly, the relationship between the coordinates and the circumferential position can be obtained.

  Next, the analysis result conversion unit 52c converts the circumferential position of each corresponding node into time. Specifically, the analysis result conversion unit 52c converts the tire circumferential direction position into time using the tire rolling speed. That is, if the tire rolling speed (° / s or rad / s) is known, the time required for one corresponding node to make one rotation (360 °) can be known. Therefore, the time required for a certain node to rotate by a certain central angle is also known. For example, when the tire rolling speed is ω [° / s], the time t required for a certain corresponding node to rotate by θ can be obtained by θ / ω. The analysis result conversion unit 52c uses the circumferential position of a corresponding node as a reference (t = 0), and sets the circumferential position θ (see FIG. 9) of each corresponding node with respect to the reference circumferential position as time t (= θ / ω). The example illustrated in FIG. 11B is a result of converting the circumferential position θ of each corresponding node into time with θ = 0 illustrated in FIG. 11A as a reference. As a result, the relationship between the circumferential position and the radial coordinate of any corresponding node shown in FIG. 11-1 is converted into the relationship between the time and the radial coordinate of one corresponding node as shown in FIG. 11-2. it can. In FIG. 11-2, the vertical axis is the radial coordinate [mm], and the horizontal axis is the time [s].

  For example, consider the case where the rolling speed of the first tire model 60 is 360 ° / s, that is, the time required for one rotation of the first tire model 60 is 1 s. At this time, the corresponding node whose circumferential position is 0 ° at time 0s rotates and moves to an angle of 180 ° at time 0.5s, and rotates to an angle of 360 ° at time 1s. Thus, the position of each corresponding node at each time can be obtained from the result of grounding analysis. The analysis result conversion unit 52 c converts the relationship between the coordinates and the rotation angle into the relationship between the coordinates and time for each node existing on the surface of the first tire model 60. Thereby, it is possible to know at which coordinates each node of the first tire model 60 is located at an arbitrary time. In this way, rotation information of the first tire model 60 is obtained. That is, the rotation information is information indicating the relationship between the displacement of the nodes existing on the surface of the first tire model 60 and time. In addition, when the 1st tire model 60 is comprised by repeating the same pitch, the relationship between the coordinate of each node of the 1st tire model 60 and time is the coordinate and time about the node of the surface in one pitch. After obtaining the relationship, the corresponding nodes in other pitches may be obtained by shifting the relationship by a time corresponding to the pitch interval.

  In this way, rotation information of the first tire model 60 is obtained. The change (displacement) with respect to the circumferential position or time of the nodes existing on the surface of the first tire model 60 is obtained from the information on the nodes of the second tire model 80. Therefore, the rotation information, more specifically, the rotation information of the first tire model 60 is obtained by using the circumferential position of the node (expressed by the central angle about the rotation axis) of the second tire model 80 as time. It will be obtained by converting.

  In the above example, the information on the nodes of the second tire model 80 is given to the nodes on the surface of the first tire model 60 and then the rotation information of the first tire model 60 is obtained. The method for obtaining the rotation information is not limited to this. For example, from the relationship between the displacement of the node of the second tire model 80 and the circumferential position, the relationship between the displacement of the node of the second tire model 80 and time, that is, rotation information (more specifically, the second tire model 80 rotation information). Then, using the relative positional relationship between the nodes of the first tire model 60 and the nodes of the second tire model 80, the obtained rotation information is given to the nodes on the surface of the first tire model 60. The rotation information of the first tire model 60 may be obtained by such a method. The method for obtaining the rotation information of the second tire model 80 is to identify a node existing in one pitch shown in FIG. 7-2 (region divided by a dotted line in FIG. 7-2) as the corresponding node 81, and to calculate the meridian of the pitch. A node existing at the same position as the corresponding node 81 in the cross section is extracted as a corresponding node 81 of each pitch for one round in the circumferential direction of the second tire model 80. Then, after the relationship between the circumferential position of each corresponding node 81 (represented by the central angle about the rotation axis) and the coordinates is extracted, the relationship is converted into the relationship between the coordinates and time.

  The rotation information may be obtained by performing rotation calculation on information representing the position of the node of the first tire model 60. The information indicating the position of the node of the first tire model 60 represents the node coordinates of the first tire model 60 or the coordinates of the position where the nodes of the first tire model 60 are projected on the second tire model 80. And rotation information may be calculated | required by performing the rotation calculation according to time and rolling speed to those coordinate information. In this embodiment, the rotation calculation does not actually rotate the first tire model 60 or the second tire model 80. For example, when a certain node rotates by θ, the calculation corresponding to the rotation is performed on the node. It is to be applied to the displacement.

  For example, the analysis result conversion unit 52 c uses the relative positional relationship between the nodes of the first tire model 60 and the nodes of the second tire model 80 as information on the nodes of the second tire model 80 after the deformation analysis is completed. Used to give to the nodes on the surface of the first tire model 60. Then, the analysis result conversion unit 52 c obtains rotation information of the first tire model 60 by performing rotation calculation on the nodes on the surface of the first tire model 60. Moreover, the analysis result conversion unit 52c obtains rotation information of the second tire model 80 by performing a rotation calculation on the displacement of the node of the second tire model 80 after the deformation analysis is completed. Then, the analysis result conversion unit 52c uses the relative positional relationship between the nodes of the first tire model 60 and the nodes of the second tire model 80 to obtain the rotation information of the second tire model 80 obtained. It is given to the node on the surface of the model 60. In this way, rotation information of the first tire model 60 is obtained.

  In obtaining the rotation information, the analysis result conversion unit 52c may provide an extended region 84 outside the second tire model 80 as shown in FIGS. 10-1 to 10-3. Since the first tire model 60 has a non-uniform shape in the circumferential direction, it may have a convex portion on the surface. For this reason, the node existing on the surface of the first tire model 60 may exist outside the second tire model 80 due to the element division relationship. In the example shown in FIG. 10A, the nodes 61A and 61D of the first tire model 60 are present on the surface of the second tire model 80, and the nodes 81E and 81F that are present on the surface of the second tire model 80 are radially outward. In addition, the nodes 61B and 61C of the first tire model 60 exist.

  In such a case, in order to approximate the coordinates of the nodes 61B and 61C of the first tire model 60, the analysis result conversion unit 52c generates an extended region 84 outside the second tire model 80 including the nodes 61B and 61C. The extended area 84 is defined as a new element. In the example illustrated in FIG. 10A, the element includes nodes 81E, 81F, 85B, and 85A. The analysis result conversion unit 52c interpolates the information on the nodes 61B and 61C of the first tire model 60 existing outside the second tire model 80 from the information on the nodes 81E, 81F, 85B and 85A constituting the element. For the interpolation, for example, linear interpolation, quadratic interpolation, spline function interpolation, or the like may be used, or the shape function of the element may be used. Note that the elements defined in the extended region 84 shown in FIG. 10-2 have the contact condition with the road surface model 66 as shown in FIG. 10-3 so as not to affect the contact shape of the second tire model 80. Do not consider. As a result, the node of the first tire model 60 that has penetrated the road surface model 66 moves to a position closest to the surface of the road surface model 66. By doing in this way, the displacement information of the node of the first tire model 60 can be obtained without shortage.

  FIG. 12 is a perspective view showing a schematic configuration of a model around the tire. If rotation information is given to the 1st tire model 60 at Step S16, processing part 52 will progress to Step S18. The analysis result conversion unit 52c creates time-series data of the surface shape of the first tire model 60 in step S18. Specifically, the analysis result conversion unit 52c uses the rotation information obtained in step S16 (that is, the relationship between the coordinates of the nodes existing on the surface of the first tire model 60 and the time) to obtain the first value at each time. The surface shape (rolling shape) of the tire model 60 is obtained. That is, the analysis result conversion unit 52c creates the surface shape of the first tire model 60 at one time by extracting the coordinates (position information) of the nodes at the same time from the relationship between the coordinates of the nodes and the time. . And the analysis result conversion part 52c can acquire the time series data of the surface shape of the 1st tire model 60 by repeating preparation of the surface shape of the 1st tire model 60 in one time. In this embodiment, since the circumferential position is converted to time as the evaluation target tire is rotated at a predetermined rotational speed, the time-series data of the surface shape of the first tire model 60 is the evaluation target This is time-series data of the surface shape of the tire when the tire rolls. Steps S16 and S18 described above correspond to the tire rolling shape creation step.

  When the processing unit 52 creates time-series data of the surface shape of the first tire model 60 in step S18, the processing unit 52 proceeds to step S20. In step S20, the second model creation unit 52d included in the processing unit 52 of the analysis / evaluation apparatus 50 creates a fluid analysis model (spatial model and simulation model) (second model creation step). Specifically, the second model creation unit 52d uses the time series data of the surface shape of the first tire model 60 created in step S18 to generate a plurality of fluid meshes (elements) around the surface shape at each time. ) 90 is created (second model creation step). At this time, the second model creation unit 52d creates a fluid analysis model by dividing a region including a region in contact with the rolling shape into a plurality of elements.

  Thereby, as shown in FIG. 12, a fluid mesh 90 can be formed around the first tire model 60. In the model for fluid analysis, a space inside the first tire model 60 and a space outside the first tire model 60 are partitioned (separated) by the wheel model 64. The first tire model 60 is in contact with the road surface model 66. When the space inside the first tire model 60 and the space outside the first tire model 60 are partitioned, the wheel model 64 may not be used. For example, a plate-like analysis model may be attached to a hole that exists on the radially inner side of the bead portion of the first tire model 60.

  After creating the fluid analysis model in step S20, the processing unit 52 proceeds to step S22. The fluid analysis unit 52e included in the processing unit 52 of the analysis / evaluation apparatus 50 performs fluid analysis as Step S22. Specifically, based on the fluid analysis model created in step S20 and various evaluation conditions, the fluid flowing in the region existing around the tire to be evaluated is analyzed. Note that fluid analysis includes air flow analysis, air resistance analysis, sound echo analysis, and fluid noise analysis such as air column resonance.

  When the fluid analysis is completed in step S22, the processing unit 52 proceeds to step S24. The evaluation unit 52f included in the processing unit 52 of the analysis / evaluation apparatus 50 evaluates the analysis result of step S22 as step S24. Specifically, the evaluation unit 52f determines whether the result of the fluid analysis matches a condition or satisfies an allowable value, and evaluates the performance of the evaluation target tire. The evaluation unit 52f can calculate the evaluation result of the tire to be evaluated as a numerical value, or can calculate the evaluation result based on an evaluation such as pass or fail. When the processing unit 52 evaluates the evaluation target tire, the processing ends.

  As described above, the simulation model creation method and simulation method of the present embodiment assume that the tire surface shape is the same in the ground contact state and the rolling state, and the rolling state from the tire surface shape calculated in the ground contact state. Convert to the tire surface shape. Thereby, a simulation model used for tire fluid analysis can be created from quasi-static contact analysis. Thus, using the ground contact analysis to predict and create the tire surface shape of the rolling analysis, the amount of calculation can be reduced compared to calculating the tire surface shape by rolling analysis of the tire. it can. As a result, the calculation time can be shortened.

  In addition, even if the simulation model created based on the quasi-static grounding analysis is used as in this embodiment, a result equivalent to the case where the simulation model is created by rolling analysis can be obtained. That is, the fluid analysis using the simulation model created by the present embodiment can obtain the same result as the fluid analysis using the simulation model created by rolling analysis of the tire analysis model. As described above, according to the present embodiment, the calculation amount can be reduced while maintaining the accuracy of the simulation, so that the efficiency of the simulation is improved. In addition, when performing fluid analysis around the tire to be evaluated as in the present embodiment, the surface shape of the tire may be acquired as time series data, and information such as internal stress distribution may not be calculated. The surface shape of the tire is information on coordinates of nodes (corresponding points) on the surface of the tire.

  In the present embodiment, rotation information obtained from the second tire model having a uniform shape in the circumferential direction is given to the first tire model, and a simulation model used for tire fluid analysis is created using the first tire model. To do. Therefore, if a plurality of different first tire models are created and the relative positional relationship between these nodes and the nodes of the second tire model is grasped, the rotation obtained from the ground contact analysis of the second tire model Only by giving information to each first tire model, time series data of the surface shape of different first tire models can be obtained. A simulation model used for fluid analysis can be created using time-series data of these surface shapes. Therefore, according to the present embodiment, for example, even when a plurality of tires having different tread patterns are evaluated, the deformation analysis is only required once. For this reason, even when evaluating a plurality of tires, it is not necessary to perform deformation analysis on all tires, so that the calculation time can be shortened. As a result, since a simulation model used for fluid analysis can be efficiently created, the efficiency of evaluation is improved.

  In this embodiment, the fluid analysis simulation is performed after creating the simulation model in all of the embodiments. However, the present embodiment is not limited to this, and the created simulation model may be used for other simulations. Moreover, you may make it perform fluid analysis with another apparatus. Moreover, in this embodiment, although the analysis result was evaluated, the evaluation by an evaluation part does not need to be performed.

  Note that the fluid mesh 90 created around the first tire model 60 in step S20 can be made into various meshes by the fluid analysis to be performed. Specifically, a mesh used for the difference method can be created, or a mesh used for the finite element method can be created. In the present embodiment, the mesh is created. However, the mesh is not limited to the mesh as long as a model used for fluid analysis around the tire can be created. That is, the fluid analysis may be executed using a space model in which the periphery of the first tire model 60 is not divided into elements. The fluid analysis model may be configured by a structured grid (orthogonal grid) targeted for the difference method, or may be configured by an unstructured grid targeted for the finite volume method or the finite element method.

  In the tire simulation method according to the present embodiment, the wheel model 64 is attached to the second tire model 80 in the contact analysis of step S12, but the second tire model 80 not attached to the wheel model 64 is grounded to the road surface model 66. The grounding analysis may be executed. Further, the wheel model 64 only needs to be able to partition an area inside the first tire model 60 and an area outside the first tire model 60 at the time of fluid analysis in step S22. Absent. In addition, what is necessary is just to set a shape of the wheel model 64 as needed, and it can also be set as the detailed shape which reproduced the actual wheel faithfully.

  FIG. 13 is an explanatory diagram showing another example in which the circumferential positions of the nodes existing on the surface of the first tire model are converted into time. In the present embodiment, the rotation information (rotation information of the first tire model 60) is information (displacement and time (position)) between nodes (corresponding nodes) existing at a pitch adjacent to the circumferential direction of the first tire model 60. May be obtained by interpolation. For example, it is possible to acquire the radial coordinates of the triangular points by performing interpolation based on the radial coordinates and the circumferential position information of the circular points shown in FIG. In this way, the rolling shape of the first tire model 60 at an arbitrary time can be obtained in more detail and with high accuracy. For interpolation, linear interpolation, quadratic interpolation, spline function interpolation, or the like can be used.

  FIG. 14 is a schematic configuration diagram illustrating another example of a fluid analysis model. 15A is an enlarged view showing a part of the fluid analysis model shown in FIG. 15-2 is an enlarged view showing a part of the fluid analysis model shown in FIG. 14 in an enlarged manner. In the fluid analysis model (space model), the fluid mesh 101 is formed around the first tire model 60, and the element structure changes according to the temporal change (rolling shape) of the surface shape of the first tire model 60. It is preferable to include one element region 102 and a second element region 104 that is formed on the outer periphery of the first element region 102 and does not change the element structure. The fluid mesh 101 is formed around the first tire model 60. The fluid analysis model also includes a wheel model 64 and a road surface model 66. In the present embodiment, the dimension of the element belonging to the first element area 102 is smaller than the dimension of the element belonging to the second element area 104. With such a structure, a phenomenon of a boundary layer (speed boundary layer, temperature boundary layer, etc.) close to the surface of the first tire model 60 can be accurately simulated.

  The first element region 102 is provided in the entire outer periphery of the first tire model 60. Further, the second element region 104 is provided outside the first element region 102, that is, in a region farther outward from the first tire model 60 in the radial direction than the first element region 102. In the first element region 102, the element structure, more specifically, the shape of the element changes according to the shape of the first tire model 60. In the present embodiment, when the first tire model 60 shown in FIG. 15-1 is rotated by an angle narrower than the rotation angle corresponding to one pitch, the first tire model 60 shown in FIG. In response to a change in the shape of the first tire model 60, the shape of the element changes from the first element region 102 to the first element region 102a. That is, the first element region 102a shown in FIG. 15-2 has a different shape from the first element region 102 shown in FIG. 15-1. On the other hand, the second element region 104 has a constant mesh regardless of the shape of the first tire model 60. That is, the second element region 104 shown in FIG. 15-2 has the same shape as the second element region 104 shown in FIG. 15-1.

  As described above, the fluid analysis model is formed around the first tire model 60, and the first element region in which the element structure changes according to the time change of the shape of the first tire model 60, and the first element region 2nd element area | region which is formed in the outer periphery and does not change an element structure according to the time change of the shape of the 1st tire model 60 is included. With such a structure, the fluid analysis model can reduce the area in which the elements are reformed in accordance with the temporal change in the shape of the first tire model 60. Accordingly, when creating the fluid analysis model, it is not necessary to regenerate all the elements of the fluid analysis model, so that the analysis / evaluation apparatus 50 reduces the burden of generating the elements.

  Further, by fixing the formation position of the element with respect to the shape of the first tire model 60, that is, by rotating the first element region 102 together with the first tire model 60, the relationship between the shape of the first tire model 60 and the mesh is changed. Can be kept constant. Further, the boundary between the first element region 102 and the second element region 104 may be constant regardless of the rotation of the first element region 102. By doing so, it is possible to create a fluid analysis model without generating elements of the fluid analysis model for each time series.

  In the fluid analysis, physical quantities are exchanged between the first element region 102 and the second element region 104. In the present embodiment, the boundary of the first element region 102 and the boundary of the second element region 104 are matched, but the boundary of the first element region 102 and the boundary of the second element region 104 do not match. Also good. That is, the boundary between the first element region 102 and the second element region 104 may partially overlap.

  FIG. 16 is a perspective view illustrating a schematic configuration of a fluid analysis model according to another example of the present embodiment. In the above-described embodiment, the fluid analysis of the space existing around the first tire model 60, the wheel model 64, and the road surface model 66 is performed. However, an analysis model of another object is provided in the space existing around the first tire model 60 It may be. For example, an analysis model of a vehicle or a part of the vehicle on which the tire to be analyzed is mounted is divided into a plurality of elements including a region in contact with the analysis model and the rolling shape of the first tire model 60 Then, a fluid analysis model (spatial model) may be created. Further, fluid analysis may be executed using the fluid analysis model.

  In this modification, the fluid analysis model 210 is created using the object surface region obtained by using the object surface information of the object (tire house, tire tester, etc.) existing around the first tire model 60. To do. That is, in addition to the tire boundary region and the contact surface region obtained from the surface information of the road surface model 66, one or more boundaries are further provided. When actually rolling a tire, members such as a wheel house and a suspension arm of the vehicle body are provided in the vicinity of the tire. Further, when testing a tire, a test apparatus is arranged in the vicinity of the tire. A member, a test apparatus, or the like included in the vehicle body reflects or absorbs radiated sound generated by the tire. In addition, a member, a test apparatus, or the like that the vehicle body has affects the air flow around the tire. Therefore, a state closer to an actual event can be reproduced by adding the member, the test apparatus, or the like as a boundary of the fluid analysis model 210.

  A fluid analysis model 210 shown in FIG. 16 has a tire house model 224 installed as an object in a tire peripheral space 222 defined by a hemispherical region 220 that is a virtual boundary, and the surface of the tire house model 224 is provided. The object surface area is provided as a boundary. The fluid analysis model 210 is created by dividing the fluid analysis model 210 provided with the tire house model 224 having the boundary condition set on the surface in this manner into a plurality of elements.

  As described above, the members existing in the vicinity of the tire are arranged in the tire peripheral space 222 as an analysis model, and the object surface region is set on the surface of the analysis model, so that the air around the tire to be evaluated The flow and sound can be analyzed under conditions closer to the actual state. A plurality of other analysis models may be provided. For example, in addition to the tire house model 224, an axle analysis model, a suspension arm analysis model, and the like may be added.

  As described above, the simulation model creation method, the simulation method, the simulation model creation apparatus, and the simulation apparatus according to the present invention are suitable for evaluating tire performance using a computer.

DESCRIPTION OF SYMBOLS 1 Tire 50 Analysis / evaluation apparatus 51 Input / output device 52 Processing part 52a 1st model creation part 52b Grounding analysis part 52c Analysis result conversion part 52d 2nd model creation part 52e Fluid analysis part 52f Evaluation part 54 Storage part 55 Display means 60 1st 1 tire model 61, 61A, 61D, 81A, 81B, 81D, 81E, 81F node 62 block 64 wheel model 66 road surface model 70, 81 corresponding node 80 second tire model 82 element 84 expansion area 90, 101 fluid mesh 102, 102a First element area 104 Second element area 210 Fluid analysis model 220 Hemisphere area 222 Tire peripheral space 224 Tire house model

Claims (14)

A first tire model that is non-uniform in a circumferential direction based on a pneumatic tire to be evaluated; a second tire model that is substantially uniform in the circumferential direction based on the pneumatic tire to be evaluated; and a wheel model; A first model creating step for creating a road surface model;
The computer executes a ground contact analysis of the second tire model to determine a displacement of a node of the second tire model; and
Rotation information representing the change of the node with respect to time, obtained by converting the circumferential position of the node of the second tire model into time by the computer, the node of the first tire model and the second tire. A tire rolling shape creation step for obtaining a rolling shape of the first tire model by giving to the first tire model using a relative positional relationship between the nodes of the model;
A second model creation step in which the computer creates a spatial model in which a region including a region in contact with the rolling shape obtained in the tire rolling shape creation step is divided into a plurality of elements;
A simulation model creation method characterized by comprising: In the tire rolling shape creation step, the computer
The simulation model creation method according to claim 1, wherein the rotation information is obtained by performing rotation calculation on information representing a position of a node of the first tire model. In the tire rolling shape creation step, the computer
The simulation model creation method according to claim 1, wherein the rotation information is obtained by interpolating information between nodes adjacent in the circumferential direction of the first tire model. In the first model creation step, the computer
The simulation model creation method according to any one of claims 1 to 3, wherein an extended region is provided outside the second tire model. In the second model creation step, the computer
A first element region that is formed around the rolling shape and the structure of the element changes according to a change in the rolling shape with time, and a second element region that is formed on the outer periphery of the first element region and does not change the element structure. The simulation model creation method according to claim 1, wherein the spatial model including an element region is created. In the second model creation step, the computer
Create an analytical model of at least a part of the vehicle on which the pneumatic tire to be evaluated is mounted, and divide the region including the region in contact with the analytical model and the rolling shape into a plurality of elements to create a spatial model The simulation model creation method according to any one of claims 1 to 5.   7. The simulation method according to claim 1, wherein the computer performs fluid analysis using the space model obtained by the simulation model creation method according to claim 1. A first tire model that is uneven in the circumferential direction based on the pneumatic tire to be evaluated, a second tire model that is substantially uniform in the circumferential direction based on the pneumatic tire to be evaluated, a wheel model, and a road surface model A first analysis model creation unit for creating
A ground contact analysis unit for performing a ground contact analysis of the second tire model to obtain a displacement of a node of the second tire model;
The rotation information representing the change of the node with respect to time, obtained by converting the circumferential position of the node of the second tire model into time, and the node of the first tire model and the node of the second tire model. An analysis result conversion unit for obtaining a rolling shape of the first tire model by applying the relative positional relationship between the first tire model and the first tire model;
A second model creation unit that creates a spatial model in which a region including a region in contact with the rolling shape obtained by the analysis result conversion unit is divided into a plurality of elements;
A simulation model creation device characterized by comprising: The analysis result conversion unit
The simulation model creating apparatus according to claim 8, wherein the rotation information is obtained by performing rotation calculation on information representing a position of a node of the first tire model. The analysis result conversion unit
The simulation model creation device according to claim 9, wherein the rotation information is obtained by interpolating information between nodes adjacent in the circumferential direction of the first tire model. The analysis result conversion unit
The simulation model creation device according to claim 9 or 10, wherein an extended region is provided outside the second tire model. The second model creation unit
A first element region that is formed around the rolling shape and the structure of the element changes according to a change in the rolling shape with time, and a second element region that is formed on the outer periphery of the first element region and does not change the element structure. The simulation model creation apparatus according to claim 9, wherein the spatial model including an element region is created. The second model creation unit
Create an analytical model of at least a part of the vehicle on which the pneumatic tire to be evaluated is mounted, and divide the region including the region in contact with the analytical model and the rolling shape into a plurality of elements to create a spatial model The simulation model creation device according to any one of claims 9 to 12.   A simulation apparatus, wherein fluid analysis is performed using the space model obtained by the simulation model creation apparatus according to any one of claims 8 to 13.

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