JP5226339B2 - Tire code analysis model creation method, apparatus, and program - Google Patents

Description

  The present invention relates to a tire code analysis model creation method, apparatus, and program for a tire code used when numerically analyzing a tire used in an automobile or the like.

  The analysis of tire behavior is based on the results of measuring the tires actually designed and manufactured and using the results of performance tests obtained by mounting them on automobiles. Can now be realized. As a main method for analyzing the tire behavior by simulation, a numerical analysis method such as a finite element method (FEM) is mainly used. FEM is a technique of modeling a structure with a finite number of elements and analyzing the behavior of the structure using a computer, and divides the structure into a finite number of elements from its features (hereinafter referred to as mesh division or Element division). In order to simulate tire behavior with high prediction accuracy, how to produce a tire model for simulation (consisting of numerical data) composed of a finite number of elements in the same way as the actual tire shape is important.

  By the way, the tire is configured to include many tire cords as well as a rubber material. This tire cord is used by forming a plurality of cores (filaments) in a complex twisted manner. Therefore, it is preferable to model the tire cord portion when the tire is simulated by FEM. As a technique that enables modeling of a tire cord, a technique that simplifies and models a tire cord so as to have equivalent rigidity is known (for example, see Patent Document 1).

Further, in a method of creating a model of a composite material in which a linear member is spirally wound around a ring-shaped member and embedded in the base material, such as a cable bead in a tire, the ring-shaped model is referred to as a base material model. A technique is disclosed in which a constraining condition is imparted to a ring-shaped model so that the contacting contact surface does not cause relative displacement with respect to the contact surface of the base material model (see, for example, Patent Document 2).
JP 2004-102424 A JP 2007-11474 A

  However, as described in Patent Document 1, it is difficult to perform highly accurate analysis by replacing the tire cord with a model simplified to have equivalent rigidity. That is, when modeling a tire, the tire cross-section elements are often modeled by three-dimensional development. However, tire cords are usually constructed by bundling a plurality of filaments, such as several wires or fibers, and the twist direction of each filament is various. It is complicated and difficult to make a finite element model carefully from the cross-section of the tire cord while considering it, resulting in an increase in the number of elements. For example, FIG. 20 shows an example in which a tire cord in which three bundles of two layers of filaments are twisted and bundled is modeled. However, it is difficult to model such a tire cord.

  In the technique described in Patent Document 2, for example, the gap between the linear member and the ring-shaped member is not considered as a model, and thus it is difficult to perform highly accurate analysis.

  In consideration of the above-described facts, the present invention provides a tire cord that enables a tire code to be analyzed with high accuracy in calculation in a tire analysis by a numerical analysis method such as a finite element method (FEM). It is an object to obtain an analysis model creation method, apparatus, and program.

  In order to achieve the above object, the invention of claim 1 is a method for creating an analysis model of a tire code that constitutes a part of a tire model used to calculate a tire corresponding to a numerical calculation model, When the tire cord is formed by bundling a plurality of filament elements while twisting them in a predetermined direction and is composed of a plurality of classification layers from the center to the outside corresponding to the twisting direction of the filament elements, the inside of the classification layers A step of defining a first two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction with respect to the first layer, and a longitudinal direction while twisting the first two-dimensional region in a corresponding twisting direction. Forming a first layer divided into predetermined division elements that can be numerically calculated while three-dimensionally expanding, and a second layer outside the first layer intersects the longitudinal direction A step of defining a second two-dimensional region including at least a filament element cross-sectional shape in a direction, and a predetermined value capable of numerical calculation while three-dimensionally developing the second two-dimensional region in the longitudinal direction while twisting in the corresponding twisting direction Forming a second layer divided by dividing elements, wherein at least one of the first two-dimensional region and the second two-dimensional region is composed of regions of filament elements and fillers, The step of defining the at least one two-dimensional region is a step of defining the element so that no element is created inside the filler not in contact with the inscribed circle and the circumscribed circle of the at least one two-dimensional region. And

  According to a second aspect of the present invention, the step of defining the second two-dimensional region includes at least a filament element cross-sectional shape in a direction intersecting a longitudinal direction with respect to the second layer outside the first layer, and It is a step of defining a second two-dimensional region so that a buffer layer is formed between the first layer and the first layer.

  The invention described in claim 3 further includes a step of dividing the buffer layer into predetermined division elements capable of numerical calculation.

  According to a fourth aspect of the present invention, there is provided an outer peripheral node of the first layer and an inner peripheral node of the buffer layer at a position corresponding to the node, and an inner peripheral node of the second layer and a position corresponding to the node. The method further includes the step of setting and associating at least one of the outer peripheral nodes of the buffer layer with a restraint condition for restraining them from moving relative to each other.

  According to a fifth aspect of the present invention, there is provided an outer peripheral node of the first layer and an inner peripheral node of the buffer layer at a position corresponding to the node, and an inner peripheral node of the second layer and a position corresponding to the node. The method further includes the step of setting and associating a contact condition defining a relative movement restriction with respect to the outer peripheral nodes of the buffer layer.

  According to a fifth aspect of the present invention, the third layer outside the second layer includes at least a filament element cross-sectional shape in a direction crossing the longitudinal direction, and a buffer layer is formed between the second layer and the second layer. A step of setting the third two-dimensional region in such a manner that the third two-dimensional region is divided by predetermined dividing elements that can be numerically calculated while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction. And a step of forming a layer.

  The present invention can be applied to a tire cord composed of a plurality of classification layers exceeding three layers from the center toward the outside. That is, the sixth aspect may be repeatedly applied from the fourth layer to the outermost classification layer, or may be applied to the outermost layer or a middle layer of the plurality of classification layers. For example, a tire cord composed of n (n is a natural number of 4 or more) classification layers is sequentially formed from the first layer to the nth layer through buffer layers. Therefore, for each layer after the fourth layer (kth layer: 3 <k <n), by replacing the (k-1) layer with the third layer and the (k-2) layer with the second layer, The present invention can be applied to each layer. In this case, the present invention is not limited to the application to all the layers from the first layer to the n-th layer. That is, the present invention can be applied only to the kth (3 <k <n) classification layer in the middle from the first layer to the nth layer.

  Further, the present invention can be applied to a tire cord group constituted by bundling a plurality of tire cords constituted by a plurality of classification layers or a tire cord group constituted by twisting a plurality. That is, by defining a tire cord composed of a plurality of classification layers as a single layer, the present invention can be applied to a tire cord group configured by twisting a plurality of tire cords composed of a plurality of classification layers. it can.

  The invention described in claim 7 further includes a step of forming a buffer layer in which the buffer region is modeled by a meshless method.

  The invention according to claim 8 is characterized in that the meshless method is a free mesh method or an element-free Galerkin method.

  The invention according to claim 9 is a step of setting a constraining element on the outer periphery of the first two-dimensional region, a step of setting a constraining element on at least the inner periphery of the second two-dimensional region, and the second Forming a second layer by dividing a two-dimensional region by a predetermined dividing element that can be numerically calculated while twisting in a corresponding twisting direction while three-dimensionally developing in the longitudinal direction; and a constraining element on the outer periphery of the first layer; An inner peripheral element of the second layer at a position corresponding to the restraining element, an inner peripheral restraining element of the second layer, and an outer peripheral element of the first layer at a position corresponding to the restraining element are respectively relative to each other. And a step of setting and associating a constraint condition for constraint so as not to move.

  The invention according to claim 10 is characterized in that the restraining element is set on at least a part of a peripheral surface, and the association is at least a part of the peripheral surface corresponding to the at least part of the surface. To do.

  The invention according to claim 11 is the filament element cross section in the direction intersecting the longitudinal direction of the outer third layer adjacent to the second layer, the step of setting a constraining element on the outer periphery of the second two-dimensional region. A step of setting a third two-dimensional region including at least a shape, a step of setting a constraint element on at least an inner periphery of the third two-dimensional region, and the third two-dimensional region in a corresponding twisting direction. Forming a third layer divided by predetermined dividing elements that can be numerically calculated while being three-dimensionally developed in the longitudinal direction while twisting, and the constraint element on the outer periphery of the second layer and the third layer at a position corresponding to the constraint element Constraint conditions for restraining the inner circumferential element of the layer, the inner circumferential restraining element of the third layer, and the outer circumferential element of the second layer at a position corresponding to the restraining element so as not to move relative to each other Setting and associating Characterized in that it comprises the al.

  The invention according to claim 12 is the step of setting a contact element on at least one of an outer periphery of the first two-dimensional region and an inner periphery of the second two-dimensional region, and corresponds to the set contact element, An outer peripheral contact element of the first layer and an inner peripheral element of the second layer in contact with the contact element, and an inner peripheral contact element of the second layer and an outer periphery of the first layer in contact with the contact element Further comprising setting and associating at least one of the elements with a contact condition defining a restriction of relative movement between the elements.

  The invention according to claim 13 is characterized in that the contact element is set on at least a part of the peripheral surface, and the association is at least a part of the peripheral surface corresponding to the at least part of the surface. To do.

  The invention according to claim 14 is the step of setting a third two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction with respect to an outer third layer adjacent to the second layer; Forming a third layer obtained by dividing a two-dimensional region of 3 by predetermined dividing elements that can be numerically calculated while twisting in a corresponding twisting direction in a three-dimensional manner, and an outer periphery of the second two-dimensional region And a step of setting a contact element on at least one of the inner circumferences of the third two-dimensional region, the contact elements on the outer circumference of the second layer corresponding to the set contact elements, and the first touching the contact elements For at least one of the inner peripheral element of the three layers and the inner peripheral contact element of the third layer and the outer peripheral element of the second layer that contacts the contact element, the relative movement between the elements is limited. Set the specified contact conditions And further comprising the step giving communication, the.

  The invention according to claim 15 is a tire cord analysis model creation device that constitutes a part of a tire model used to calculate a tire corresponding to a numerical computation model, wherein the tire cord comprises a plurality of filament elements. Are formed by being bundled while being twisted in a predetermined direction, and are composed of a plurality of classification layers from the center toward the outside corresponding to the twisting direction of the filament element, First definition means for defining a first two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the direction, and three-dimensional development in the longitudinal direction while twisting the first two-dimensional region in a corresponding twisting direction The first forming means for forming the first layer divided into predetermined division elements that can be numerically calculated, and the direction intersecting the longitudinal direction of the second layer outside the first layer Second definition means for defining a second two-dimensional region including at least a filament element cross-sectional shape, and numerical calculation can be performed while three-dimensionally developing the second two-dimensional region in the longitudinal direction while twisting in the corresponding twisting direction. Second forming means for forming a second layer divided by predetermined dividing elements, wherein at least one of the first two-dimensional region and the second two-dimensional region is a region of a filament element and a filler. And at least one of the first definition means and the second definition means is defined so that no element is created inside the filler that is not in contact with the inscribed circle and the circumscribed circle of the at least one two-dimensional region. It is characterized by.

  According to a sixteenth aspect of the present invention, there is provided a computer for creating an analysis model of a tire code constituting a part of a tire model used for calculating a tire corresponding to a numerical calculation model, wherein the tire code includes a plurality of tire codes. When the filament element is formed by being bundled while being twisted in a predetermined direction and is composed of a plurality of classification layers from the center toward the outside corresponding to the twist direction of the filament element, the inner first layer of the classification layers First definition means for defining a first two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction; and 3 in the longitudinal direction while twisting the first two-dimensional region in a corresponding twisting direction. A first forming means for forming a first layer divided into predetermined divided elements that can be numerically calculated while developing dimensions, and a second layer outside the first layer, A second definition means for defining a second two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting with the second element, and three-dimensionally developing the second two-dimensional region in the longitudinal direction while twisting in the corresponding twisting direction. And a second forming means for forming a second layer divided by predetermined dividing elements capable of numerical calculation, and at least one of the first two-dimensional area and the second two-dimensional area is a filament element And at least one of the first definition means and the second definition means includes an element inside the filler that is not in contact with the inscribed circle and the circumscribed circle of the at least one two-dimensional area. This is a tire code analysis model creation program that functions as a means for defining that a tire code is not created.

  As described above, according to the present invention, there is an effect that the analysis of the tire code can be performed with high accuracy in calculation.

  (First embodiment)

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, the present invention is applied to the creation of an analysis model for tire behavior analysis.

  (Device configuration)

  FIG. 1 shows an outline of a personal computer for creating a tire code analysis model and executing a tire behavior simulation using the created analysis model. The personal computer includes a keyboard 10 for inputting data and the like, a computer main body 12 that predicts tire performance according to a pre-stored processing program, and a CRT 14 that displays calculation results of the computer main body 12 and the like.

  The computer main body 12 includes a flexible disk unit (FDU) into which a flexible disk (FD) as a recording medium can be inserted and removed. Note that processing routines and the like described later can be read from and written to the flexible disk FD using the FDU. Therefore, a program and a processing routine to be described later may be recorded in the FD in advance, and the processing program recorded in the FD may be executed via the FDU. Further, a mass storage device (not shown) such as a hard disk device is connected to the computer main body 12, and the processing program recorded on the FD is stored (installed) in the mass storage device (not shown) and executed. Also good. As the recording medium, there are optical disks such as CD-ROM and DVD, and magneto-optical disks such as MD and MO. When these are used, a corresponding device may be used instead of or in addition to the FDU. In addition to a personal computer, a workstation or a super computer may be used for tire analysis.

  (Tire code)

  First, a tire cord included in a tire, particularly a steel cord, is a single tire cord formed by twisting a plurality of thin cords (hereinafter referred to as filaments). In this case, a tire cord formed by twisting a plurality of filaments is used as a first layer (single layer twist) tire cord, and a second layer filament is twisted around the tire cord to form a two-layer twisted tire cord. it can. At this time, the first layer and the second layer are reversely rotated in the rotating direction. Further, the twist pitch and the filament diameter are not necessarily the same in the first layer and the second layer. By repeating this, a plurality of layers of tire cords can be created.

  In addition, by inserting a filler (matrix) such as rubber between the filaments of the tire cord, it is possible to suppress rust when used in the tire and moisture adheres around the cord due to trauma and improve durability. it can. A thicker tire cord can be created by further twisting these single or multiple layers of twisted tire cords.

  As shown in FIG. 8, for example, in the case of a single twist cord, it is easy to model a filler around a filament and create a model with solid elements. In the case of multi-layer twisting, if the twisting direction and the pitch are the same between the layers, the positional relationship between the filaments is the same everywhere as long as it is rotated about the longitudinal direction of the tire cord. Therefore, even when there is a filler around the filament, if the element can be divided in the cross section, an entire tire cord model can be created by extruding this in the tire cord longitudinal direction.

  However, ordinary cords have different twisting directions and pitches between layers, and cannot be easily extruded as described above to create a tire cord model. It is also possible to create a three-dimensional solid model using CAD or the like. However, since the shape of the filler between the filaments is very complicated, it is very difficult to create a divided element (mesh) divided into elements. Specifically, there is a case where a tetrahedron cannot be created with automatic element division. Further, rubber usually used as a filler for tire cords is almost incompressible and has a Poisson's ratio close to 0.5. It is known in the finite element method that a hexahedron or a pentahedron (for example, a triangular prism) is necessary when such a material is analyzed with a finite element method with high accuracy. Since it is virtually impossible to automatically generate such a pentahedron in the filler portion obtained from CAD data, the analysis accuracy cannot be improved in consideration of the tire code. It was.

  (Tire cord modeling)

  In consideration of the above facts, in the present embodiment, the tire cord is classified and modeled by layer, and the entire tire cord is modeled by providing a relationship between the layers.

  FIG. 5 shows the processing routine of the tire code analysis model creation program according to the present embodiment, which is executed by the personal computer (FIG. 1). 5 is executed, a tire code analysis model for dropping the tire code alone or the tire code included in the tire design plan into a numerical analysis model is created, and the data is stored in a personal computer. be able to. The creation of the tire cord analysis model differs slightly depending on the numerical analysis method used. In this embodiment, a finite element method (FEM) is used as a numerical analysis method, and an analysis model of a tire cord to be created is divided into a plurality of elements by element division corresponding to the finite element method (FEM), for example, mesh division. This is the result of dividing the tire into a numerical value into an input data format for a computer program created based on numerical and analytical methods. This element division means to divide the tire cord into small (finite) small parts. After calculating every small part and calculating all the small parts, the whole response can be obtained by adding all the small parts.

  First, in step 200 of FIG. 5, a tire code to be modeled to be created as an analysis model is designated. In this step 200, a tire code for which an analysis model is to be created or a design plan (tire shape, structure, material, etc.) of a tire including the tire code is determined. The above is not limited to the tire design plan, but includes the case of analyzing an existing tire. That is, the tire cord itself included in the existing tire may be set as the target model.

  For example, in step 200, the designation is made by selecting one of the tire codes included in the tire model. This designation may be performed by reading a user's keyboard input value and setting a corresponding part in the tire as a tire code, or automatically setting a part predetermined as a tire code from tire design plan data. it can. In this step 200, data relating to material properties such as Young's modulus, shear elastic modulus, Poisson's ratio, etc., and diameter, twist direction and layer configuration of the designated tire cord are obtained. To do.

  FIG. 4 shows an example of a tire cross-section model, and shows a pneumatic tire 20 having a carcass 22 divided for each of a plurality of rubber members. The carcass 22 is folded back by a bead 26. The inner side of the carcass 22 is an inner liner 24, and a bead rubber 36 is disposed on the inner liner 24 so as to extend. A substantially triangular area formed by the folded carcass 22 is a bead filler 28. A belt 30 is disposed above the carcass 22, a tread rubber 32 having a groove is disposed on the outer side in the radial direction of the belt 30, and a side rubber 34 is disposed on the outer side in the axial direction of the carcass 22. Yes. In addition, although the example which divided | segmented the tire cross-section model into multiple for every rubber member was given, you may divide | segment into arbitrary shapes, such as a triangle, according to the design objective. Any one tire cord may be selected from the tire cords included in the members constituting these tires.

  Next, although details will be described later, in step 202 of FIG. 5, a two-dimensional shape of the designated tire cord (which may be referred to as a cross-sectional shape or a two-dimensional model) is created, and the created tire cord is created in the next step 204. A two-dimensional shape is developed in the longitudinal direction of the tire cord to create a three-dimensional shape. When the modeling of the designated tire code is completed, it is determined whether or not the above processing has been completed for all tire models included in the tire model (step 206). If the determination is affirmative, this processing routine is terminated. On the other hand, if the result in Step 206 is negative, the process returns to Step 200, and the above processing is repeated for other tire cords.

  Hereinafter, in order to simplify the description, an example in which a belt is designated as a tire cord and one tire cord included in the belt is modeled as an analytical model capable of numerical calculation will be described in detail. The present invention is not limited to the belt of the tire cord, but can be applied to any one as long as a plurality of filaments such as metal wires are bundled. In many cases, the belt includes a cord formed by a bundle of a plurality of filaments such as several wires. This belt is modeled for each wire and an analysis model is obtained. That is, in the present embodiment, an analysis model of a tire cord is obtained by modeling in detail including a twist direction of each filament, using a belt in which metal wires as filaments are bundled as an example of a tire cord.

  (Tire code 2D model creation)

  In the process of creating the cross-sectional shape (two-dimensional model) in step 202, the creation process routine of FIG. 6 is executed. In step 210, the cross-sectional structure and material characteristics of the tire cord specified in step 200 are read, and in step 212, the filaments are classified by layer. In this classification, a plurality of filaments included in a designated tire cord are classified by layer for each filament in the same twist direction. FIG. 9 shows, as an example, a three-layer tire cord 40 having the same twist direction filament 48 in each of the innermost layer 42, the intermediate layer 44, and the outermost layer 46.

  In the next step 214, the first layer filament (cross section) is divided into elements so as to have a predetermined shape, and in the next step 216, a circumscribed shape surrounding the periphery of the first layer filament group is determined. In FIG. 10A, each of the filaments 48 included in the innermost layer 42 of the tire cord 40 as the first layer is divided into elements, and a circumscribed circle 50 of the filament 48 is defined as a circumscribed shape surrounding the periphery of the filament group. The case is shown. In the above description, the first layer is defined as the innermost layer 42, but the first layer may be the outermost layer 46.

  In the example of FIG. 10, the circumscribed circle 50 is employed as the circumscribed shape. However, the circumscribed shape is not limited to a circle, and may be an ellipse, a square, a triangle, a polygon, or the like. Moreover, it may be concave or convex between the filaments.

  Next, in step 218, the filler existing around the filament 48 is divided into elements so as to have a predetermined shape (see FIG. 10B).

  When the setting of the cross-sectional shape of the first layer is completed as described above, the cross-sectional shape is sequentially set in the same manner as described above for the adjacent layers of the first layer. Specifically, the process proceeds to step 222, and the element is divided into the adjacent layer in the outward direction, here the second layer, in the same manner as in step 214 above. In the next step 224, the circumscribed shape surrounding the periphery of the filament group of the outer adjacent layer (here, the second layer) is determined in the same manner as in the above step 216. In addition, an inscribed shape is defined inside the filament group of the outer adjacent layer (here, the second layer). The inscribed shape is determined so that a gap, that is, a buffer layer is formed between the inscribed shape of the inward adjacent layers (here, the first layer).

  In FIG. 11A, each of the filaments 48 included in the intermediate layer 44 of the tire cord 40 as the second layer is divided into elements, and a circumscribed circle 56 of the filament 48 is defined as a circumscribed shape surrounding the periphery of the filament group. The inscribed circle 54 is defined as the inscribed shape.

  In the example of FIG. 11, a case where a circular shape is adopted as the circumscribed shape is shown, but the shape is not limited to a circular shape, and may be an ellipse, a square, a triangle, a polygon, or the like. Moreover, it may be concave or convex between the filaments.

  In the next step 226, as in step 218 described above, the filler existing around the filament 48 is divided into elements so as to have a predetermined shape (see FIG. 11B).

  FIG. 12 shows a case where the first layer and the second layer are divided into elements. As shown in the figure, a buffer layer 57 is provided between a circumscribed circle 50 of the first layer and an inscribed circle 54 of the second layer. By providing the buffer layer 57 between the first layer and the second layer in this way, a model is created as compared with a model that restrains the first layer and the second layer without providing the buffer layer. Becomes easy.

  In the next step 228, the buffer layer 57 is divided into elements. For example, as shown in FIG. 13 (A), the nodes generated when the first layer filament or filler is divided into elements, and the nodes generated when the second layer filament or filler is divided into elements. , The buffer layer 57 can be divided into elements. If the filler is not divided into elements, the nodes are appropriately set on the circumscribed circle 50 of the first layer and the inscribed circle 54 of the second layer, and the buffer layer 57 is divided into elements by connecting these nodes. be able to.

  When the setting of the cross-sectional shape of the outer adjacent layer (here, the second layer) is completed as described above, the process proceeds to step 230 to determine whether the setting of the cross-sectional shape for all the layers of the tire cord 40 is completed. In the case of negative, the cross-sectional shape is set for the adjacent layers in the same manner as described above. That is, in the example of FIG. 9, the processing of Step 222 to Step 228 is executed for the outermost layer 46 because of the three-layer structure. On the other hand, when the result in step 230 is affirmative, the process proceeds to step 232.

  When creating a two-dimensional model of the cross-sectional shape, it is possible to create the entire cross-sectional shape at the same time, but after creating a two-dimensional model for a part of the cross-section, by copying the created two-dimensional model, A two-dimensional model having a cross-sectional shape can be created in a short time and with high accuracy. For example, as shown in FIG. 10, the innermost layer 42 has symmetry in the rotational direction, and the innermost layer 42 has three filaments arranged at equal intervals, so that it has the same shape every 120 degrees. Become. Considering this, after creating a cross-sectional shape obtained by dividing a part of the basic shape into elements, it is possible to periodically create element divisions of the same shape by developing them in the rotation direction. If created in this way, the accuracy can be improved by aligning the element sizes. Moreover, element generation can be performed in a short time.

  In the above processing (FIG. 6), the case where the buffer layer is defined for all the layers from the innermost layer to the outermost layer of the tire cord 40 has been described, but the present invention is not limited to this, and the buffer layer It may be possible to specify the layer between the layers.

  FIG. 13B shows the two-dimensional model created as described above. In this way, modeling is possible very easily because the buffer layer is provided between the layers and the elements are divided.

  By the way, if the deformation calculation of the tire model created as described above is performed, a large deformation occurs between the filaments at the time of pulling or bending deformation, which also increases the deformation of the filler around the filament, and the elements of the filler May be distorted, making it impossible to perform deformation calculation.

  Therefore, in step 232, some elements of the filler in each layer from the innermost layer to the outermost layer (from the first layer to the third layer in the case of FIG. 13B) are deleted. In order to perform an analysis considering the interaction between the layers, the surface of each layer, i.e., the element of the filler in contact with the inscribed circle and the circumscribed circle of each layer is not deleted, and the inscribed circle and the circumscribed circle of each layer are not deleted. Only the internal elements of the filler that are not in contact with are removed. Specifically, for example, the internal element of the filler as shown by the hatched area in FIG. 13B is deleted. Thereby, the number of elements of a filler can be reduced. Further, for example, the analysis can be performed even when the tire cord is rotated and the filler is largely deformed.

  In FIG. 13B, only some internal elements of the filler of each layer are indicated by hatched areas, but only some internal elements of the filler of each layer may be deleted, You may make it delete all the internal elements of the filler of each layer. Further, instead of deleting some or all of the internal elements of all layers of the filler, some or all of the internal elements of the filler of some layers may be deleted.

  Further, in the above, after the tire model is created by performing the element division of each layer, the internal elements of the filler of each layer are collectively deleted, but the processing of step 232 is omitted, and in steps 218 and 226 When the filler is divided into elements, the elements may be created only in the area in contact with the inscribed circle and the circumscribed circle of each layer, and the elements may not be created in the filler of each layer.

  (Create a three-dimensional tire cord model)

  In the process of creating the three-dimensional shape in step 204, the creation process routine of FIG. 7 is executed. In step 240, the cross-sectional shape (two-dimensional model) which is the two-dimensional shape of the tire code obtained in step 202 (the execution result of the processing routine of FIG. 6) is read, and the first layer of the two-dimensional shape is read. In the next step 242, the innermost layer 42 is developed while being rotated along the longitudinal direction of the tire cord 40 and in the twisting direction. Note that the processing of step 242 includes element division processing.

  That is, since the first layer is a single-stranded tire cord, the three-dimensional model is pushed by a predetermined distance in the tire cord longitudinal direction while rotating the cross-sectional shape (two-dimensional model) around the longitudinal direction of the tire cord. Can be created (see FIG. 8).

  For example, the twisting direction of the corresponding layer (that is, the first layer) is known, and if a predetermined distance in the longitudinal direction of the tire cord is determined, the cross-sectional shape (two-dimensional model) divided into the elements in the longitudinal direction of the tire cord By extruding, a three-dimensional model can be created for the first layer of the tire cord. The predetermined distance in the longitudinal direction is preferably made to correspond to the length of the element when dividing in accordance with a predetermined pitch. A cross-sectional shape (two-dimensional model) rotated according to the twisting direction is formed at a position separated by a predetermined distance in the longitudinal direction, and a cross-sectional shape (two-dimensional model) between both cross-sectional shapes (two-dimensional model) is formed. It is only necessary to create a model with solid elements to connect the locus positions.

  Even when a filler is provided around the filament of the first layer as in this embodiment, it is easy to model the filler around the filament and create a model with solid elements. That is, even when there is a filler around the filament, if the element is divided in the cross-sectional shape, a three-dimensional model of the corresponding layer can be created by extruding this in the tire cord longitudinal direction.

  FIG. 14 shows a three-dimensional model of the innermost layer 42 having three filaments 48 as an example and twisting them in the same twist direction. FIG. 14A shows a case where the innermost layer 42 is constituted by only the filament 48, and FIG. 14B shows a case where the innermost layer 42 is constituted by providing a filler around the filament.

  As shown in FIG. 14, the first layer (innermost layer 42) is twisted by being rotated clockwise as viewed from the longitudinal direction. A three-dimensional model can be created by developing several parts per pitch and developing in the longitudinal direction while twisting. In this modeling, since the filament and the surrounding filler share a node, the element division in the cord longitudinal direction of the filament and the filler is the same. At this time, if the number of element divisions per pitch is reduced, irregularities on the surface of the filler increase, but a three-dimensional model that can shorten the analysis time can be provided by reducing the number of elements. On the other hand, when the number of element divisions is increased, the surface becomes smooth, and by increasing the number of elements, a three-dimensional model that can shorten the analysis time can be provided. In the example of FIG. 14, it is divided into 10 per pitch.

  When the creation of the three-dimensional model of the first layer is completed as described above, the process proceeds to step 244, and the two-dimensional shapes of the buffer layer and the outer adjacent layer are set at positions adjacent to each other in the outer direction of the current layer. Here, the two-dimensional model of the intermediate layer 44 that is the buffer layer and the second layer is set around the innermost layer 42 in the cross-sectional shape (two-dimensional model) that is the two-dimensional shape of the tire code read in step 240 above. To do.

  In the next step 246, as in step 242 described above, the outer adjacent layer (here, the second layer) is developed along the longitudinal direction of the tire cord 40 and in the twisting direction.

  The twist direction of the second layer with respect to the first layer may be the same or opposite. This twist direction is not limited to the relationship between the first layer and the second layer, but the twist direction of each layer is not limited, and the definition of the twist direction defined in the following description is limited thereto. It is not a thing. That is, the twisting direction may be clockwise or counterclockwise, and the cord can be configured by any combination of twisting directions.

  FIG. 15 shows a three-dimensional model of only the intermediate layer 44 having nine filaments 48 as an example and twisted in the same twist direction around the innermost layer 42. FIG. 15A shows a case where the intermediate layer 44 is configured only by the filament 48, and FIG. 15B shows a case where the intermediate layer 44 is configured by providing a filler around the filament.

  As shown in FIG. 15, the second layer (intermediate layer 44) is twisted by rotating counterclockwise when viewed from the longitudinal direction. In the example of FIG. 15, the twist pitch is set to twice that of the first layer. A three-dimensional model can be created by developing several parts per pitch and developing in the longitudinal direction while twisting. In this modeling, since the filament and the surrounding filler share a node, the element division in the cord longitudinal direction of the filament and the filler is the same. At this time, if the number of element divisions per pitch is reduced, irregularities on the surface of the filler increase, but a three-dimensional model that can shorten the analysis time can be provided by reducing the number of elements. On the other hand, when the number of element divisions is increased, the surface becomes smooth, and by increasing the number of elements, a three-dimensional model that can shorten the analysis time can be provided. In the example of FIG. 15, 20 divisions per pitch.

  When the creation of the three-dimensional model of the outer adjacent layer (here, the second layer) is completed as described above, the process proceeds to step 250 to determine whether the creation of the three-dimensional model for all layers of the tire cord 40 is completed. In the case of negative, a three-dimensional model is sequentially created for the adjacent layers in the same manner as described above. That is, in the example of FIG. 9, because of the three-layer structure, the processing from step 244 to step 248 is executed for the outermost layer 46. On the other hand, if the determination at step 250 is affirmative, the present processing routine is terminated.

  As an example, FIG. 16 shows a three-dimensional model modeled up to the second layer, and FIG. 17 shows a three-dimensional model modeled up to the third layer (outermost layer).

  Through the above processing, a layer composed of a filament group can be formed sequentially from the inner layer to the outer layer, and a three-dimensional model composed of a plurality of layers in which buffer layers are provided between adjacent layers can be created.

  In the above processing (FIG. 7), the case where the buffer layers are provided for all the layers from the innermost layer to the outermost layer of the tire cord 40 has been described. However, the present invention is not limited to this, You may enable it to designate the interlayer provided.

  As described above, the present embodiment can be easily applied to a tire cord including two or more classification layers from the center toward the outside. That is, as described in the processing of steps 222 to 230 and the processing of steps 244 to 250, since it is repeatedly applied from the second layer to the outermost classification layer, two layers, three layers, four layers, and so on. Applicable to multiple layers. Also, any layer can be specified and applied.

  Further, in the present embodiment, since the buffer layer is provided between the layers for modeling, the model can be created easily and in a short time compared to the case of creating a model in which the layers are constrained.

  Further, the present invention can be applied to a tire cord group constituted by bundling a plurality of tire cords constituted by a plurality of classification layers or a tire cord group constituted by twisting a plurality. In other words, by defining a tire cord composed of a plurality of classification layers as a single layer, the present embodiment is configured by tying a tire cord group composed of a plurality of tire cords composed of a plurality of classification layers or a plurality of twists. It can be applied to the configured tire cord group.

  Although not shown, a three-dimensional model can be created for a spiral tire cord by the same processing as described above.

  (Behavior simulation)

  Next, an example in which a tire model is formed using the tire code of the above three-dimensional model and the behavior of the tire is analyzed will be described.

  FIG. 2 shows a processing routine of the tire behavior analysis program. In step 100, a design plan (tire shape, structure, material, etc.) of a tire to be subjected to behavior analysis is determined. Note that the setting in step 100 is not limited to the tire design plan, but includes the case of analyzing an existing tire. That is, the existing tire itself may be set as the target model. In the next step 102, a tire tire model for creating a tire design plan into a numerical analysis model is created. The creation of the tire model differs slightly depending on the numerical analysis method used. In this embodiment, a finite element method (FEM) is used as a numerical analysis method. Therefore, the tire model created in step 102 is divided into a plurality of elements by element division corresponding to the finite element method (FEM), for example, mesh division, and the tire is created based on a numerical / analytical method. This is a digitized input data format for computer programs. This element division means dividing an object such as a tire and a road surface (described later) into several small (finite) small parts. After calculating every small part and calculating all the small parts, the whole response can be obtained by adding all the small parts.

  In the creation of the tire model in step 102, a tire model creation routine shown in FIG. 3 is executed. First, in step 112, a tire radial section model (tire section model, that is, tire section data) is created. In addition, rubber in the tire cross section, supplementary teaching materials (belts, plies, etc., reinforcing cords made of iron / organic fibers, etc., bundled in a sheet shape, etc.) are modeled according to the modeling method of the finite element method, respectively. . In the next step 114, two-dimensional tire cross-section data (tire radial cross-section model) is developed for one turn (360 degrees) in the circumferential direction to create a three-dimensional (3D) model of the tire.

  For tire cords that contain reinforcing materials (belts, plies, etc., reinforcing cords made of iron / organic fibers, etc., bundled in a sheet shape, etc.), a detailed analysis model will be created as described later. Then, what is necessary is just to create a model as a uniform tire code.

  Next, in step 116 of FIG. 3, the constituent material of the rubber of each part of the tire is set. In this step, a constituent material having material characteristics such as rigidity corresponding to each part of the tire is selected. In the next step 118, a tire code analysis model creation process for modeling the tire code in detail is executed, and this routine is terminated. In the tire code analysis model creation process in step 118, the above-described processing routine for creating the tire code analysis model (see FIG. 5) is executed.

  After the tire model including the finite element model (analysis model) of the tire cord 40 created as described above is created, the process proceeds to step 104 in FIG. 2, and road surface setting, that is, creation of the road surface model and input of the road surface state are performed. Made. In this step 104, the road surface is modeled and input for setting the modeled road surface to an actual road surface state. The road surface is modeled by dividing the road surface shape into elements and selecting the road surface friction coefficient μ and inputting the road surface state. For example, depending on the road surface condition, there is a road friction coefficient μ corresponding to dry (DRY), wet (WET), on ice, snow, unpaved, etc., so by selecting an appropriate value for the friction coefficient μ, The road surface condition can be reproduced.

  A fluid model may be created and provided between the road surface and the tire model. The fluid model divides and models a part (or all) of a tire, a ground contact surface, and a fluid region including a region where the tire moves and deforms.

  In this way, when the road surface condition is input, the boundary condition is set in the next step 106. The boundary conditions are necessary for analysis of the tire model, that is, for simulating the behavior of the tire, and are various conditions given to the tire model. In the setting of the boundary condition in step 106, first, an internal pressure is applied to the tire model, and at least one of rotational displacement and straight displacement (displacement may be force or speed) is applied to the tire model, a predetermined load load, Give at least one of In addition, when considering friction with the road surface, only one of rotational displacement (or force or speed) or straight displacement (or force or speed) may be used.

  Next, a deformation calculation of the tire model as an analysis is performed based on the numerical model created or set up to step 106. That is, when the setting of the boundary condition is completed in step 106, the process proceeds to step 108, and the tire model is calculated for deformation. In this step 108, deformation calculation of the tire model is performed based on the finite element method from the tire model and the given boundary conditions. This deformation calculation repeats the tire model deformation calculation (for example, by repeating the calculation within 1 msec) in order to obtain the tire rolling state (to obtain a transient state), and each time the boundary condition May be updated. In addition, the deformation calculation can employ a predetermined calculation time assuming that the tire deformation is in a steady state.

  When the deformation calculation of the tire model is performed, the deformation of the filament portion having a high elastic modulus is reduced, and the deformation of the virtual filler around the filament having a low elastic modulus is increased. Further, when the twist rotation direction and the twist pitch of each layer are different, the buffer layer is very deformed, and the element may be distorted and the deformation calculation may not be performed. For example, as shown in FIG. 18A, even if the elements of the buffer layer are not distorted so much at the beginning of the analysis, as the analysis proceeds, the deformation of the elements of the buffer layer (as shown in FIGS. (Distortion) increases and analysis may be difficult.

  In such a case, it is determined whether or not the deformation of the element of the buffer layer falls outside the allowable range. If the deformation of the buffer layer falls outside the allowable range, only the buffer layer may be divided (remeshed) again. This makes it possible to eliminate the distortion of the elements in the buffer layer and continue the analysis as shown in FIG. Thus, by remeshing only the buffer layer, the time required for remeshing can be shortened compared to the case of remeshing the entire tire model.

  Note that whether or not to re-mesh, that is, whether or not the deformation of the element is outside the allowable range, can be determined based on criteria such as the twist angle of the mesh of the buffer layer and the aspect ratio. For example, the determination can be made based on items related to mesh quality in PDQ (Product Data Quality) guideline V4.1 of JAMA / JAAPIA (Japan Automobile Manufacturers Association / Japan Auto Parts Industries Association).

  In the next step 110, the calculation result is output. This calculation result uses a physical quantity at the time of tire deformation. Specifically, side deflection amount, contact shape, contact pressure distribution, lateral force acting on the tire center, and the like.

  The calculation result may be output by visualizing the value or distribution of the shape of the contact portion of the tire, the distribution of contact pressure, the force acting on the center of the tire, or the like. These can be derived from the calculation result value, amount or rate of change, force direction (vector), and distribution, and can be presented in an easy-to-understand manner by representing them with a diagram etc. along with the tire model and pattern periphery. Visualization is possible.

  As described above, in the present embodiment, the tire cord included in the tire is modeled in detail by the finite element model, and the tire behavior including the model (analysis model) is analyzed in accordance with the actual shape. It becomes possible to do. Therefore, it is possible to analyze the tire cord with higher accuracy than in the case where the tire cord is analyzed by a simplified element.

  In the present embodiment, since the buffer layer is provided between the layers for modeling, it is possible to analyze with high accuracy even when the twist rotation direction and the twist pitch are different between the layers.

  Further, in the present embodiment, the case has been described in which the buffer layer is divided into elements by connecting the nodes on the outer periphery of the inner layer adjacent to the buffer layer and the nodes on the inner periphery of the outer layer adjacent to the buffer layer. However, such a method may make it difficult to generate elements.

  Therefore, the nodes on the outer periphery of the inner adjacent layer of the buffer layer or the nodes on the inner periphery of the outer adjacent layer of the buffer layer, and the nodes provided on the outer periphery or the inner periphery independently of these nodes; A constraint element may be defined for each of the models, and a model to which a constraint condition is constrained so that the constraint element does not move relatively may be created.

  The process for giving this constraint condition is performed so that, for example, the nodes on the inner circumference of the buffer layer and the nodes provided on the outer circumference of the adjacent inner layer of the buffer layer do not move relative to each other. This is a process of setting and associating a constraint condition that mutually restrains the node and the node provided on the inner periphery of the outer layer adjacent to the buffer layer so as not to move relative to each other. Thereby, it is possible to easily divide the elements while maintaining the constraints of the inner adjacent layer, the buffer layer, and the outer adjacent layer.

  In addition, a constraint condition is not given, but a node on the outer periphery of the adjacent inner layer of the buffer layer or a node on the inner periphery of the outer adjacent layer of the buffer layer, and these nodes are independent on the outer periphery. Alternatively, a contact element may be defined for each of the nodes provided on the inner periphery, and a model in which a contact condition is assigned to the contact element may be created.

  This contact condition prescribes a relative movement restriction for each of the adjacent inner adjacent layer, buffer layer, and outer adjacent layer. For example, the processing for assigning the contact condition sets a contact condition that allows the nodes on the inner circumference of the buffer layer and the nodes provided on the outer circumference of the adjacent layer in the inner direction of the buffer layer to move relatively while contacting each other. And a process for setting and associating a contact condition that allows the node on the outer periphery of the buffer layer and the node provided on the inner periphery of the adjacent layer in the outer direction of the buffer layer to move relative to each other. It is.

  There are three types of contact conditions: a contact condition based on sliding resistance, a contact condition based on a friction coefficient, and a contact condition based on shape preservation. The contact condition by sliding resistance is to add sliding resistance having a predetermined characteristic (function) with respect to relative movement of adjacent layers. Specifically, for example, the sliding resistance defines the coordinate relationship for a three-dimensional separation between the nodes on the inner circumference of the buffer layer and the nodes provided on the outer circumference of the inner layer adjacent to the buffer layer. These contact points are related by using as a contact condition. This sliding resistance is a linear function, a gradually increasing function of asymptotic characteristics, a gradually decreasing hyperbolic function, a function by a polynomial in which the value of sliding resistance changes stepwise according to input, a nonlinear function, etc. Can be determined by a combination of functions. For example, up to a predetermined input value, a predetermined value of a large sliding resistance is in a restrained state in which the same position is maintained and moved, and when the input value exceeds this value, each slides apart by a predetermined amount of deviation. A function can be defined to be in a state.

  The contact condition based on the friction coefficient is to add a predetermined coefficient of friction to the relative movement (sliding) of adjacent layers. Specifically, for example, the frictional coefficient defines the coordinate relationship for a three-dimensional separation between the nodes on the inner periphery of the buffer layer and the nodes provided on the outer periphery of the adjacent inner layer of the buffer layer. Associate these nodes as contact conditions. This friction coefficient may be a constant value or may be determined by various functions similar to the above.

  The contact condition by shape preservation is to add a shape preservation coefficient such as a predetermined elastic modulus to the relative movement of adjacent layers. Specifically, for example, a coordinate relationship for three-dimensional separation between the nodes on the inner periphery of the buffer layer and the nodes provided on the outer periphery of the adjacent inner layer of the buffer layer is defined by the shape conservation coefficient. These contact points are related by using as a contact condition. This shape preservation coefficient may be a constant value or may be determined by various functions similar to the above. In addition, it is preferable to prescribe | regulate a shape preservation | save coefficient with respect to each direction of three dimensions considering the change of a layer. Thereby, contact conditions can be defined for each of the three-dimensional directions.

  When the contact condition is given in this way, force and displacement can be transmitted between the layers. In addition, since it is not completely constrained, the accuracy of overall deformation was maintained by obtaining the friction coefficient by actual measurement, especially when using a virtual filler, or by setting the friction coefficient so that the overall deformation would match the actual measurement. The deformation of the buffer layer can be reduced as it is.

  Even when the constraint condition or the contact condition is applied, it is preferable to remesh only the buffer layer when the mesh quality of the buffer layer deteriorates.

  In the present embodiment, the case where the buffer layer is divided into elements has been described. However, the present invention is not limited to this, and the buffer layer may be modeled by a meshless method in which element division is not performed. Examples of the meshless method include a free mesh method and an element free Galerkin method.

  In this case, it is possible to analyze the deformation of the buffer layer by defining an arbitrary plurality of points in the buffer layer and calculating the interaction between the points using a known free mesh method or element free Galerkin method. .

  (Example)

  Next, embodiments of the present invention will be described in detail.

The tire cord modeled and prototyped in this example has a filament diameter (2r) of 0.25 mm in all, and the first layer has a filament of {2r / 3 · (3) ^1/2 · 0.125} mm in circumference. Three of them are arranged in a uniform arrangement on the top, and the second layer is arranged so as to be in contact with the first layer, and the third layer is arranged so as to be in contact with the second layer. The twist pitch was 5, 10, and 15 mm from the first layer, and the element division in the tire cord longitudinal direction was 10, 20, and 30 / pitch from the first layer. This tire cord was modeled by a length of 30 mm. Also, rubber was used as a filler around the filament. The analysis was carried out by fixing in both end planes and pulling in the longitudinal direction.

  FIG. 19 shows a three-dimensional model before and after deformation. FIG. 4A is a three-dimensional model before deformation, and FIG. 4B is a three-dimensional model after deformation. As can be understood from the figure, a result conforming to the actual shape was obtained in which the angle formed by the filament with the longitudinal direction of the cord is reduced by tensile deformation, and the distance between the nodes in the longitudinal direction is increased.

  In addition, when the same analysis as described above was performed on a conventional tire model in which the inside of the filler of each layer was not divided into the tire model in which the internal elements of the filler of each layer were deleted as in the present invention, tensile strain was found. After analyzing up to 0.25%, the element shape of the filler deteriorated and the analysis stopped.

  On the other hand, in the analysis in the tire model in which the elements in the hatched area in FIG. 13B are deleted, the analysis was performed up to the point where the tensile strain was 1.0%.

  Thus, it was found that the tire cord can be analyzed with higher accuracy by using the analysis model of the present embodiment.

  (Second Embodiment)

  Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and the detailed description is abbreviate | omitted.

  In this embodiment, a buffer layer is not provided between adjacent layers as in the first embodiment, and a filament (cross section) of each layer is divided into elements, and a circumscribed shape and a constraining element surrounding the periphery are defined. Constraining between the inscribed shape and the circumscribed shape so as to constrain adjacent layers so that they do not move relative to each other so that the two-dimensional model is twisted and rotated in the longitudinal direction in order from the inner layer to the outer layer. A method for obtaining an analysis model by creating a three-dimensional shape by associating elements will be described. Hereinafter, only different parts from the first embodiment will be described.

  (Tire code 2D model creation)

  In the process of creating the cross-sectional shape (two-dimensional model) in step 202 of FIG. 5 described in the first embodiment, the creation process routine of FIG. 21 is executed. Steps 210 to 218, 222, 226, and 230 are the same as those in FIG.

  In step 220, a constraint element for the first layer is defined. As shown in FIG. 23C, the constraining element 52 is positioned on the circumscribed shape (here, circumscribed circle 50) determined in step 216. The constraining element 52 generates a force acting on the outside caused by deformation or movement of the filament group included in the first layer (here, the innermost layer 42) or a force acting on the first layer from the outside. It is for associating between one layer and an adjacent layer. That is, here, the constraining element 52 that associates the circumscribed circle 50 with the second layer is determined. In the following description, the case where the constraint element 52 is indicated by a point will be described. However, it may be a line segment or a surface after three-dimensional development described later. In addition, since the element division of the filler is performed in Step 218, a constraint element is defined on the outer peripheral portion of the filler.

  When the setting of the cross-sectional shape of the first layer is completed as described above, the cross-sectional shape is sequentially set in the same manner as described above for the adjacent layers of the first layer. Specifically, the process proceeds to step 222, and the element is divided into the adjacent layer in the outward direction, here the second layer, in the same manner as in step 214 above. In the next step 224, the circumscribed shape surrounding the periphery of the filament group of the outer adjacent layer (here, the second layer) is determined in the same manner as in the above step 216. In addition, an inscribed shape inscribed in the filament group of the outer adjacent layer (here, the second layer) is defined around the filament group of the inner adjacent layer (here, the first layer). In FIG. 24A, each of the filaments 48 included in the intermediate layer 44 of the tire cord 40 as the second layer is divided into elements, and a circumscribed circle 56 of the filament 48 is defined as a circumscribed shape surrounding the filament group. The inscribed circle 54 is defined as the inscribed shape.

  In the example of FIG. 24, the case where a circular shape is adopted as the circumscribed shape is shown, but the shape is not limited to a circular shape, and may be an ellipse, a square, a triangle, a polygon, or the like. Moreover, it may be concave or convex between the filaments.

  In addition, since the inscribed circle 54 of the inscribed shape of the second layer is constrained to the circumscribed shape of the first layer, it is easy to cooperate and associate (for example, join) if both are the same shape. However, it is not limited to setting both to the same shape. Even if the two shapes are different, they can be constrained after moving without causing stress or distortion so that both shapes can be constrained immediately after the start of calculations such as simulation described later, even if the shapes are different. Can be set to.

  In the next step 226, as in the above step 218, the filler existing around the filament 48 is divided into elements so as to have a predetermined shape (see FIG. 24B). It should be noted that the element division of the filler need not be defined when an external constraint is not necessary, for example, when a single filament is analyzed in the same manner as described above.

  In the next step 228, the constraining elements of the outer adjacent layer (here the second layer) are defined. That is, a restraining element for at least the inner adjacent layer (here, the first layer) is defined. This step 228 is a process for determining a cooperation element for constraining at least the inscribed shape with the inner adjacent layer (here, the first layer). As shown in FIG. 24C, the inner restraint element 59 is positioned on the inscribed shape (here, the inscribed circle 54) determined in step 224. If there is a further adjacent layer (here, the third layer) outside the layer (here, the second layer), the constraining element for the adjacent layer (here, the third layer) is the same as in step 220 above. Determine. As shown in FIG. 24C, the constraining element 58 is positioned on the circumscribed shape (here, circumscribed circle 56) determined in step 224. When there is no adjacent layer outside the layer, it is not necessary to determine a constraint element for the adjacent layer. However, for the outermost layer that does not have an adjacent layer on the outside, predefining the constraint elements outside the outermost layer is preferable when the tire cord is treated as a group of cords as a model for other simulations. .

  When the setting of the cross-sectional shape of the outer adjacent layer (here, the second layer) is completed as described above, the process proceeds to step 230 to determine whether the setting of the cross-sectional shape for all the layers of the tire cord 40 is completed. In the case of negative, the cross-sectional shape is set for the adjacent layers in the same manner as described above. That is, in the example of FIG. 9, the processing of Step 222 to Step 228 is executed for the outermost layer 46 because of the three-layer structure. On the other hand, if the determination in step 230 is affirmative, the present processing routine is terminated.

  When creating a two-dimensional model of the cross-sectional shape, it is possible to create the entire cross-sectional shape at the same time, but after creating a two-dimensional model for a part of the cross-section, by copying the created two-dimensional model, A two-dimensional model having a cross-sectional shape can be created in a short time and with high accuracy. For example, as shown in FIG. 23, the innermost layer 42 has symmetry in the rotation direction, and the innermost layer 42 has three filaments arranged at equal intervals, so that it has the same shape every 120 degrees. Become. Considering this, after creating a cross-sectional shape obtained by dividing a part of the basic shape into elements, it is possible to periodically create element divisions of the same shape by developing them in the rotation direction. If created in this way, the accuracy can be improved by aligning the element sizes. Moreover, element generation can be performed in a short time.

  In the above processing (FIG. 21), the case where the constraint elements are defined for all the layers from the innermost layer to the outermost layer of the tire cord 40 has been described, but the present invention is not limited to this, You can define constraints by specifying layers. In this case, only the process of creating the two-dimensional model is executed for the processes of steps 220 to 230, and the layer designation is performed for the definition of the constraint element. That is, it is assumed that a numerical value representing a layer has been input in advance for the layer of definition of the constraint element, and a process for determining whether or not to define the constraint element is added between steps 226 and 228. This determination process determines whether or not the numerical value representing the layer input in advance is the current layer. When the determination is affirmative, the process proceeds to step 228, and when the determination is negative, the process proceeds to step 230.

  FIG. 25 shows the two-dimensional model created as described above. FIG. 25A shows a two-dimensional model 43A of the three-layer tire cord 40 shown in FIG. 9, and FIG. 25B shows a two-dimensional model 43B of the two-layer tire cord 40 that can be created in the process. Indicated. FIG. 26 shows an example of a two-dimensional model 45 of a tire cord 41 formed by bundling three three-layer tire cords 40. In the two-dimensional model 45 of the three bundled tire cords 41 shown in FIG. 26, the restraining elements are defined in the circumscribed shape (cord surface) of the third layer (outermost layer 46) of each tire cord 40. The three layered tire cords 40 can be bound to each other. Modeling rubber or the like outside the tire cord 40 and the tire cord 41 described above is very easy because it only creates an element outside the circle.

  (Create a three-dimensional tire cord model)

  In the process of creating the three-dimensional shape in step 204 of FIG. 5 described in the first embodiment, the creation process routine of FIG. 22 is executed. In step 240, the cross-sectional shape (two-dimensional model) which is the two-dimensional shape of the tire code obtained in step 202 (the execution result of the processing routine of FIG. 21) is read, and the first layer of the two-dimensional shape is read. In the next step 242, the innermost layer 42 is developed while being rotated along the longitudinal direction of the tire cord 40 and in the twisting direction. Note that the processing of step 242 includes element division processing.

  That is, since the first layer is a single-stranded tire cord, the three-dimensional model is pushed by a predetermined distance in the tire cord longitudinal direction while rotating the cross-sectional shape (two-dimensional model) around the longitudinal direction of the tire cord. Can be created (see FIG. 8).

  For example, the twisting direction of the corresponding layer (that is, the first layer) is known, and if a predetermined distance in the longitudinal direction of the tire cord is determined, the cross-sectional shape (two-dimensional model) divided into the elements in the longitudinal direction of the tire cord By extruding, a three-dimensional model can be created for the first layer of the tire cord. The predetermined distance in the longitudinal direction is preferably made to correspond to the length of the element when dividing in accordance with a predetermined pitch. A cross-sectional shape (two-dimensional model) rotated according to the twisting direction is formed at a position separated by a predetermined distance in the longitudinal direction, and a cross-sectional shape (two-dimensional model) between both cross-sectional shapes (two-dimensional model) is formed. It is only necessary to create a model with solid elements to connect the locus positions.

  At the time of creating the three-dimensional model, the constraint element 52 determined at the time of creating the two-dimensional model may be determined for each processing distance or may be determined at a predetermined interval. In addition, a curve that becomes the locus of the constraint element 52 may be determined. That is, as long as the constraining element 52 is positioned on the cross-sectional shape of the created three-dimensional model, either a point or a curve may be used.

  When the creation of the three-dimensional model of the first layer is completed as described above, the process proceeds to step 244, and the two-dimensional shape of the outer adjacent layer is set at the position adjacent to the current layer in the outer direction. Here, the two-dimensional model of the intermediate layer 44 that is the second layer of the cross-sectional shape (two-dimensional model) that is the two-dimensional shape of the tire code read in step 240 is set around the innermost layer 42. In the next step 246, as in step 242 described above, the outer adjacent layer (here, the second layer) is developed along the longitudinal direction of the tire cord 40 and in the twisting direction. At the time of creating the three-dimensional model, the position on the three-dimensional model (the point or curve serving as the locus of the restricting element 52) is also determined for the restricting element (at least the inner restricting element) determined at the time of creating the two-dimensional model. In addition, when there is no adjacent layer outside the layer, a process for determining a constraint element for the adjacent layer is not necessary. However, for the outermost layer that does not have an adjacent layer on the outside, predefining the constraint elements outside the outermost layer is preferable when the tire cord is treated as a group of cords as a model for other simulations. .

  The twist direction of the second layer with respect to the first layer may be the same or opposite. This twist direction is not limited to the relationship between the first layer and the second layer, but the twist direction of each layer is not limited, and the definition of the twist direction defined in the following description is limited thereto. It is not a thing. That is, the twisting direction may be clockwise or counterclockwise, and the cord can be configured by any combination of twisting directions.

  Next, in step 248, a constraining element is associated between the inscribed shape of the outward adjacent layer (here, the second layer) and the circumscribed shape of the previous layer (here, the first layer). In this process, the previous layer (first layer) and the outer adjacent layer (second layer) are relative to each other in order to create a three-dimensional model of tire cords that restrain each other so as not to move relative to each other. This is a process of setting and associating a restraint condition for restraining so as not to move. In the specific processing here, the relationship between the constraint element 52 of the first layer and the inner peripheral element of the second layer at the position corresponding to the constraint element 52 is relatively different between the constraint element and the element at the corresponding position. Set and associate the constraint condition that restrains it from moving. Similarly, the relation between the restraining element 59 inside the second layer and the element on the outer periphery of the first layer at the position corresponding to the restraining element 59 moves relative to each other between the restraining element and the element at the corresponding position. Set and associate the constraint condition to constrain it.

  FIG. 27 shows a cross-sectional shape near the boundary between the innermost layer 42 and the intermediate layer 44 of the tire cord 40. 27A shows the relationship between the innermost layer 42 and the intermediate layer 44, and FIG. 27B shows the relationship when the innermost layer 42 and the intermediate layer 44 are joined. A constraining element 52 (drawing points Pa and Pb as an example in FIG. 27) is defined in the circumscribed circle 50 of the first layer which is the innermost layer 42. At the time of creating the three-dimensional model of the intermediate layer 44, the association elements (drawing points Da and Db as an example in FIG. 27) corresponding to the constraint elements 52 of the innermost layer 42 are determined.

  Therefore, in the process of step 248, the constraint element 52 and the association element are specifically defined as having a coordinate relationship in which the point Pa and the point Da and the point Pb and the point Db have a coordinate relationship that is not three-dimensionally separated. The constraint element 52 is associated with the association element.

  Thereby, between the restraining element 52 and the associating element, a force acting on the outside caused by deformation or movement of the filament group included in the first layer (here, the innermost layer 42), or the first layer An externally applied force can be associated between the first layer and the adjacent layer.

  Although not shown in the figure, a constraining element 59 is defined on the inscribed circle 54 of the second layer, which is the intermediate layer 44, as described above, and corresponds to the constraining element 59 when creating the three-dimensional model of the intermediate layer 44. The association element is determined on the circumscribed circle 50 of the first layer which is the innermost layer 42. Therefore, the constraint element 59 is associated with the associated element on the condition that the constraint element 59 and the associated element on the circumscribed circle 50 have a coordinate relationship that is not three-dimensionally separated. Thereby, between the restraining element 59 and the association element, a force acting on the outside caused by deformation or movement of the filament group included in the second layer (here, the intermediate layer 44), or the second layer An externally applied force can be associated between the first layer and the adjacent layer.

  In the above description, a case has been described in which association elements are individually defined corresponding to each of the constraint elements 52 and 59. However, the association may be performed between the constraint elements. For example, the closest constraint elements may be associated with each other as a constraint condition having a coordinate relationship in which the constraint elements are not three-dimensionally separated. In this case, the association element is not necessary, and can be executed by processing using only the constraint element.

  When the creation of the three-dimensional model of the outer adjacent layer (here, the second layer) is completed as described above, the process proceeds to step 250 to determine whether the creation of the three-dimensional model for all layers of the tire cord 40 is completed. In the case of negative, a three-dimensional model is sequentially created for the adjacent layers in the same manner as described above. That is, in the example of FIG. 9, because of the three-layer structure, the processing from step 244 to step 248 is executed for the outermost layer 46. On the other hand, if the determination at step 250 is affirmative, the present processing routine is terminated.

  Through the above processing, a layer composed of a filament group is formed sequentially from the inner layer to the outer layer, and a three-dimensional model composed of a plurality of layers in which adjacent layers are constrained to each other can be created.

  In the above processing (FIG. 22), the case where the constraint elements are defined for all the layers from the innermost layer to the outermost layer of the tire cord 40 has been described, but the present invention is not limited to this, You can define constraints by specifying layers. In this case, only the process of creating the three-dimensional model is executed for the processes of steps 244 to 250, and the layer designation is performed for the definition of the constraint element. That is, it is assumed that a numerical value representing a layer has been input in advance for the layer of definition of the constraint element, and a process for determining whether or not to associate the constraint element is added between steps 246 and 248. This determination process determines whether or not the numerical value representing the layer inputted in advance is the current layer. When the determination is affirmed, the process proceeds to step 248, and when the determination is negative, the process proceeds to step 250.

  As described above, the present embodiment can be easily applied to a tire cord including two or more classification layers from the center toward the outside. That is, as described in the processing of steps 222 to 230 and the processing of steps 244 to 250, since it is repeatedly applied from the second layer to the outermost classification layer, two layers, three layers, four layers, and so on. Applicable to multiple layers. Also, any layer can be specified and applied.

  Further, the present invention can be applied to a tire cord group constituted by bundling a plurality of tire cords constituted by a plurality of classification layers or a tire cord group constituted by twisting a plurality. In other words, by defining a tire cord composed of a plurality of classification layers as a single layer, the present embodiment is configured by tying a tire cord group composed of a plurality of tire cords composed of a plurality of classification layers or a plurality of twists. It can be applied to the configured tire cord group.

  In FIG. 28, as an example of the three-dimensional model created in accordance with the above processing, each of the innermost layer 42, the intermediate layer 44, and the outermost layer 46 has filaments 48 in the same twist direction and filaments 48 in different twist directions between the layers. A three-dimensional model 47 of the tire cord 40 having a layer structure is shown. FIG. 29 shows an example of a three-dimensional model 49 of a tire cord 41 configured by bundling three three-layer tire cords 40 shown in FIG.

  The three-dimensional model 47 shown in FIG. 28 is a three-dimensional model constrained between layers, and the three-dimensional model 49 shown in FIG. 29 is constrained to the circumscribed shape (cord surface) of the third layer (outermost layer 46) of each tire cord 40. Since the elements are defined, a three-dimensional model in which three tire cords 40 of three-layer twist are constrained to each other. Modeling rubber or the like outside the tire cord 40 and the tire cord 41 described above is very easy because it only creates an element outside the circle.

  Although not shown, a three-dimensional model can be created for a spiral tire cord by the same processing as described above.

  (Third embodiment)

  Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and the detailed description is abbreviate | omitted.

  In this embodiment, a buffer layer is not provided between adjacent layers as in the first embodiment, and a filament (cross section) of each layer is divided into elements, and a circumscribed shape surrounding the periphery and a contact element are defined. Inscribed shape so that adjacent layers are in contact with each other according to the contact conditions that regulate the relative movement between elements by twisting and rotating the two-dimensional model in the longitudinal direction in order from the inner layer to the outer layer A method of obtaining an analysis model by creating a three-dimensional shape by associating contact elements between the shape and the circumscribed shape will be described. Hereinafter, only different parts from the first embodiment will be described.

  (Tire code 2D model creation)

  In the process of creating the cross-sectional shape (two-dimensional model) in step 202 of FIG. 5 described in the first embodiment, the creation process routine of FIG. 30 is executed. Steps 210 to 218, 222, 226, and 230 are the same as those in FIG.

  In step 220, contact elements for the first layer are defined. As shown in FIG. 32C, the contact element 53 is located on the circumscribed shape (here, circumscribed circle 50) determined in step 216. The contact element 53 generates a force acting on the outside caused by contact due to deformation or movement of the filament group included in the first layer (here, the innermost layer 42) or a force acting on the first layer from the outside. , For associating between the first layer and the adjacent layer. That is, here, the contact element 53 that associates the circumscribed circle 50 with the second layer is determined. In the following description, a case where the contact element 53 is indicated by a point will be described. However, a line segment or a surface after three-dimensional development described later may be used. In addition, since the element division of the filler is performed in Step 218, a contact element is defined on the outer peripheral portion of the filler.

  When the setting of the cross-sectional shape of the first layer is completed as described above, the cross-sectional shape is sequentially set in the same manner as described above for the adjacent layers of the first layer. Specifically, the process proceeds to step 222, and the element is divided into the adjacent layer in the outward direction, here the second layer, in the same manner as in step 214 above. In the next step 224, the circumscribed shape surrounding the periphery of the filament group of the outer adjacent layer (here, the second layer) is determined in the same manner as in the above step 216. In addition, an inscribed shape inscribed in the filament group of the outer adjacent layer (here, the second layer) is defined around the filament group of the inner adjacent layer (here, the first layer). In FIG. 33A, each of the filaments 48 included in the intermediate layer 44 of the tire cord 40 as the second layer is divided into elements, and a circumscribed circle 56 of the filament 48 is defined as a circumscribed shape surrounding the filament group. The inscribed circle 54 is defined as the inscribed shape.

  In the example of FIG. 33, the case where a circular shape is adopted as the circumscribed shape is shown, but the shape is not limited to a circular shape, and may be an ellipse, a square, a triangle, a polygon, or the like. Moreover, it may be concave or convex between the filaments.

  In addition, since the inscribed circle 54 of the inscribed shape of the second layer is in contact with the circumscribed shape of the first layer, if they are the same shape, they can be easily linked and associated (for example, joined). However, it is not limited to setting both to the same shape. Even if the shapes of the two are different, they contact each other in the initial shape, or after moving without causing stress or distortion so that both shapes match immediately after the start of calculations such as simulation described later. Can be set to.

  In the next step 226, as in the above step 218, the filler existing around the filament 48 is divided into elements so as to have a predetermined shape (see FIG. 33B). The element division of the filler is defined when there is no contact with the outside, for example, when analyzing the filament alone in the same manner as described above, for example, when no force acts on an external member. There is no need.

  In the next step 228, the contact elements of the outer adjacent layer (here the second layer) are defined. That is, the contact element for at least the inner adjacent layer (here, the first layer) is defined. This step 228 is a process for determining a cooperating element for making contact with the inner adjacent layer (here, the first layer) at least in the inscribed shape. As shown in FIG. 33C, the inner contact element 61 is located on the inscribed shape (here, the inscribed circle 54) determined in step 224. If there is a further adjacent layer (here, the third layer) outside the layer (here, the second layer), the contact element for the adjacent layer (here, the third layer) is the same as in step 220 above. Determine. As shown in FIG. 33C, the contact element 60 is positioned on the circumscribed shape (here, circumscribed circle 56) determined in step 224. When there is no adjacent layer outside the layer, it is not necessary to determine a contact element for the adjacent layer. However, for the outermost layer where there is no adjacent layer on the outside, it is preferable to pre-define the contact elements outside the outermost layer when the tire cord is treated as a group of cords as a model for other simulations. .

  When the setting of the cross-sectional shape of the outer adjacent layer (here, the second layer) is completed as described above, the process proceeds to step 230 to determine whether the setting of the cross-sectional shape for all the layers of the tire cord 40 is completed. In the case of negative, the cross-sectional shape is set for the adjacent layers in the same manner as described above. That is, in the example of FIG. 9, the processing of Step 222 to Step 228 is executed for the outermost layer 46 because of the three-layer structure. On the other hand, if the determination in step 230 is affirmative, the present processing routine is terminated.

  When creating a two-dimensional model of the cross-sectional shape, it is possible to create the entire cross-sectional shape at the same time, but after creating a two-dimensional model for a part of the cross-section, by copying the created two-dimensional model, A two-dimensional model having a cross-sectional shape can be created in a short time and with high accuracy. For example, as shown in FIG. 32, the innermost layer 42 has symmetry in the rotation direction, and since three filaments are arranged at equal intervals in the innermost layer 42, the same shape is obtained every 120 degrees. Become. Considering this, after creating a cross-sectional shape obtained by dividing a part of the basic shape into elements, it is possible to periodically create element divisions of the same shape by developing them in the rotation direction. If created in this way, the accuracy can be improved by aligning the element sizes. Moreover, element generation can be performed in a short time.

  In the above processing (FIG. 30), the case where the contact elements are defined for all the layers from the innermost layer to the outermost layer of the tire cord 40 has been described, but the present invention is not limited to this, A contact element can be defined by specifying a layer. Moreover, the layer which defines a contact element should just be at least one of an outer periphery and an inner periphery. In this case, only the process of creating the two-dimensional model is executed for the processes of steps 220 to 230, and the layer designation is performed for the definition of the contact element. That is, it is assumed that a numerical value representing the layer has been input in advance for the layer of the contact element definition, and a process for determining whether or not to define the contact element is added between steps 226 and 228. This determination process determines whether or not the numerical value representing the layer input in advance is the current layer. When the determination is affirmative, the process proceeds to step 228, and when the determination is negative, the process proceeds to step 230. In this case, when the layer defining the contact element is defined for at least one of the outer periphery and the inner periphery, the contact element may be specified for at least one of the outer periphery and the inner periphery of the corresponding layer in addition to the layer specification.

  FIG. 34 shows the two-dimensional model created as described above. 34A shows a two-dimensional model 62A of the three-layer tire cord 40 shown in FIG. 9, and FIG. 34B shows a two-dimensional model 62A of the two-layer tire cord 40 that can be created in the process. Indicated. FIG. 35 shows an example of a two-dimensional model 63 of a tire cord 41 formed by bundling three three-layer tire cords 40. In the two-dimensional model 63 of the three tire cords 41 bundled as shown in FIG. 35, contact elements are defined in the circumscribed shape (cord surface) of the third layer (outermost layer 46) of each tire cord 40. The three layered tire cords 40 can be brought into contact with each other. Modeling rubber or the like outside the tire cord 40 and the tire cord 41 described above is very easy because it only creates an element outside the circle.

  When the deformation between the layers is small or when it is desired to suppress the deformation between the layers, the relationship between the contact element and the cooperation element associated with the contact element can be modeled so as to constrain each other. As will be described in detail later, this can be achieved by making the contact condition a characteristic that the degree of restraint changes according to the force acting on the contact element. For example, when the input is small (when it is equal to or less than a predetermined value), the contact condition is set to be mutually restrained, and when the input is exceeded, the contact condition is set to be relatively movable while contacting.

  (Create a three-dimensional tire cord model)

  In the process of creating the three-dimensional shape in step 204, the creation process routine of FIG. 31 is executed. In step 240, the cross-sectional shape (two-dimensional model), which is the two-dimensional shape of the tire code obtained in step 202 (the execution result of the processing routine of FIG. 30), is read, and the first layer of the two-dimensional shape is read. In the next step 242, the innermost layer 42 is developed while being rotated along the longitudinal direction of the tire cord 40 and in the twisting direction. Note that the processing of step 242 includes element division processing.

  That is, since the first layer is a single-stranded tire cord, the three-dimensional model is pushed by a predetermined distance in the tire cord longitudinal direction while rotating the cross-sectional shape (two-dimensional model) around the longitudinal direction of the tire cord. Can be created (see FIG. 8).

  For example, the twisting direction of the corresponding layer (that is, the first layer) is known, and if a predetermined distance in the longitudinal direction of the tire cord is determined, the cross-sectional shape (two-dimensional model) divided into the elements in the longitudinal direction of the tire cord By extruding, a three-dimensional model can be created for the first layer of the tire cord. The predetermined distance in the longitudinal direction is preferably made to correspond to the length of the element when dividing in accordance with a predetermined pitch. A cross-sectional shape (two-dimensional model) rotated according to the twisting direction is formed at a position separated by a predetermined distance in the longitudinal direction, and a cross-sectional shape (two-dimensional model) between both cross-sectional shapes (two-dimensional model) is formed. It is only necessary to create a model with solid elements to connect the locus positions.

  At the time of creating the three-dimensional model, the contact element 53 determined at the time of creating the two-dimensional model may be determined for each processing distance or may be determined at a predetermined interval. Further, a curve serving as a locus of the contact element 53 may be determined. That is, if the contact element 53 is configured to be positioned on the cross-sectional shape of the created three-dimensional model, either a point or a curve may be used.

  When the creation of the three-dimensional model of the first layer is completed as described above, the process proceeds to step 244, and the two-dimensional shape of the outer adjacent layer is set at the position adjacent to the current layer in the outer direction. Here, the two-dimensional model of the intermediate layer 44 that is the second layer of the cross-sectional shape (two-dimensional model) that is the two-dimensional shape of the tire code read in step 240 is set around the innermost layer 42. In the next step 246, as in step 242 described above, the outer adjacent layer (here, the second layer) is developed along the longitudinal direction of the tire cord 40 and in the twisting direction. At the time of creating the three-dimensional model, a position on the three-dimensional model (a point or a curve serving as a trajectory of the contact element 53) is also determined with respect to the contact element (at least the inner contact element) determined at the time of creating the two-dimensional model. When there is no adjacent layer outside the layer, it is not necessary to determine the contact element for the adjacent layer. However, for the outermost layer where there is no adjacent layer on the outside, it is preferable to pre-define the contact elements outside the outermost layer when the tire cord is treated as a group of cords as a model for other simulations. .

  The twist direction of the second layer with respect to the first layer may be the same or opposite. This twist direction is not limited to the relationship between the first layer and the second layer, but the twist direction of each layer is not limited, and the definition of the twist direction defined in the following description is limited thereto. It is not a thing. That is, the twisting direction may be clockwise or counterclockwise, and the cord can be configured by any combination of twisting directions.

  Next, in step 248, a contact element is associated between the inscribed shape of the outwardly adjacent layer (here, the second layer) and the circumscribed shape of the previous layer (here, the first layer). This process is for creating a three-dimensional model of a tire cord that can move relatively while contacting a plurality of adjacent layers. In this process, a contact condition is set and associated that enables relative movement while contacting the previous layer (first layer) and the outer adjacent layer (second layer). This contact condition prescribes | regulates the restriction | limiting of a relative movement about several adjacent layers. In the specific processing here, the relationship between the contact element 53 of the first layer and the inner peripheral element of the second layer at the position corresponding to the contact element 53 is relatively different between the contact element and the element at the corresponding position. Set and associate contact conditions for movably contacting. Similarly, with respect to the relationship between the contact element 61 inside the second layer and the outer peripheral element of the first layer at the position corresponding to the contact element 61, the contact element and the element at the corresponding position move relative to each other. Set and associate contact conditions where possible.

  FIG. 36 shows a cross-sectional shape in the vicinity of the boundary between the innermost layer 42 and the intermediate layer 44 of the tire cord 40. 36A shows the relationship between the innermost layer 42 and the intermediate layer 44, and FIG. 36B shows the relationship when the innermost layer 42 and the intermediate layer 44 are in contact (for example, bonded). A contact element 53 (drawing points Pa and Pb as an example in FIG. 36) is defined on the circumscribed circle 50 of the first layer which is the innermost layer 42. At the time of creating the three-dimensional model of the intermediate layer 44, association elements (drawing points Da and Db as an example in FIG. 16) corresponding to the contact element 53 of the innermost layer 42 are determined.

  When the innermost layer 42 and the intermediate layer 44 are in contact with each other, the innermost layer 42 and the intermediate layer 44 are relatively movable. At this time, if it is assumed that the innermost layer 42 and the intermediate layer 44 are rigid bodies, when a force (deformation) accompanying movement occurs in one of the layers, it acts on the other layer and self-shape-preserving force (for example, rigidity) ) Etc., the other layer moves (deforms). More specifically, the contact element 53 and the association element change from a restrained state in which the contact element 53 is moved while maintaining the same position to a sliding state in which each is displaced by a predetermined amount. It is defined that the relationship between the innermost layer 42 and the intermediate layer 44 changes from a restraint state to a sliding state in accordance with an input (acting force or generated force) (relative movement Stipulate restrictions) as a contact condition.

  There are three types of contact conditions: a contact condition based on sliding resistance, a contact condition based on a friction coefficient, and a contact condition based on shape preservation. As shown in FIG. 36C, the contact condition by the sliding resistance is to add a sliding resistance having a predetermined characteristic (function) with respect to the relative movement between the innermost layer 42 and the intermediate layer 44. . Specifically, the contact element 53 and the association element are associated with each other as a contact condition that the point Pa and the point Da and the point Pb and the point Db are defined in terms of the sliding resistance as a contact condition. . This sliding resistance is a linear function, a gradually increasing function of asymptotic characteristics, a gradually decreasing hyperbolic function, a function by a polynomial in which the value of sliding resistance changes stepwise according to input, a nonlinear function, etc. Can be determined by a combination of functions. For example, up to a predetermined input value, a predetermined value of a large sliding resistance is in a restrained state in which the same position is maintained and moved, and when the input value exceeds this value, each slides apart by a predetermined amount of deviation. A function can be defined to be in a state.

  Further, as shown in FIG. 36D, the contact condition based on the friction coefficient adds a predetermined coefficient of friction to the relative movement (sliding) between the innermost layer 42 and the intermediate layer 44. . Specifically, the contact element 53 and the associated element are associated with each other under the condition that the frictional coefficient defines the coordinate relationship for the point Pa and the point Da and the point Pb and the point Db to be separated three-dimensionally. This friction coefficient may be a constant value or may be determined by various functions similar to the above.

  As shown in FIG. 36E, the contact condition by shape preservation is to add a shape preservation coefficient such as an elastic coefficient having a predetermined value with respect to the relative movement between the innermost layer 42 and the intermediate layer 44. Specifically, the contact element 53 and the association element are associated with each other as a contact condition that the point Pa and the point Da and the point Pb and the point Db are defined by a shape preservation coefficient as a coordinate relationship for three-dimensional separation. . This shape preservation coefficient may be a constant value or may be determined by various functions similar to the above. Note that the shape preservation coefficient is preferably defined for each of the three-dimensional directions as shown in FIG. Thereby, contact conditions can be defined for each of the three-dimensional directions.

  Therefore, in the process of step 248, specifically, the contact element 53 and the associated element (point Pa and The points Da and Pb and the point Db) are associated with each other by applying a contact condition that defines a relative movement restriction that enables a three-dimensionally spaced coordinate relationship.

  Thereby, between the contact element 53 and the association element, a force acting on the outside caused by deformation or movement of the filament group included in the first layer (here, the innermost layer 42), or the first layer An externally applied force can be associated between the contacted first layer and the adjacent layer.

  Although not shown, the contact element 61 is defined on the inscribed circle 54 of the second layer, which is the intermediate layer 44, as described above, and corresponds to the contact element 61 when creating the three-dimensional model of the intermediate layer 44. The association element is determined on the circumscribed circle 50 of the first layer which is the innermost layer 42. Therefore, the contact element 61 and the association element on the circumscribed circle 50 are associated with each other by giving a contact condition that defines a restriction on relative movement. Thereby, between the contact element 61 and the association element, a force acting on the outside caused by deformation or movement of the filament group included in the second layer (here, the intermediate layer 44), or the second layer An externally applied force can be associated between the first layer and the adjacent layer so that the contacted state can be reproduced.

  In the above description, the case where the association elements are individually determined corresponding to each of the contact elements 53 and 59 has been described. However, the association may be performed between the contact elements. For example, the closest contact elements may be associated with each other by applying a contact condition that defines a relative movement restriction. In this case, the association element is not necessary, and can be executed by processing using only the contact element.

  When the creation of the three-dimensional model of the outer adjacent layer (here, the second layer) is completed as described above, the process proceeds to step 250 to determine whether the creation of the three-dimensional model for all layers of the tire cord 40 is completed. In the case of negative, a three-dimensional model is sequentially created for the adjacent layers in the same manner as described above. That is, in the example of FIG. 9, because of the three-layer structure, the processing from step 244 to step 248 is executed for the outermost layer 46. On the other hand, if the determination at step 250 is affirmative, the present processing routine is terminated.

  By the above processing, a layer composed of filament groups can be formed sequentially from the inner layer to the outer layer, and a three-dimensional model composed of a plurality of layers in which adjacent layers are in contact with each other can be created.

  In the above processing (FIG. 31), the case where the contact elements are defined for all the layers from the innermost layer to the outermost layer of the tire cord 40 has been described, but the present invention is not limited to this, A contact element can be defined by specifying a layer. In this case, only the process of creating the three-dimensional model is executed for the processes of steps 244 to 250, and the layer designation is performed for the definition of the contact element. That is, it is assumed that a numerical value representing a layer has been input in advance for the layer of definition of the contact element, and a process for determining whether or not to associate the contact element is added between steps 246 and 248. This determination process determines whether or not the numerical value representing the layer inputted in advance is the current layer. When the determination is affirmed, the process proceeds to step 248, and when the determination is negative, the process proceeds to step 250.

  As described above, the present embodiment can be easily applied to a tire cord including two or more classification layers from the center toward the outside. That is, as described in the processing of steps 222 to 230 and the processing of steps 244 to 250, since it is repeatedly applied from the second layer to the outermost classification layer, two layers, three layers, four layers, and so on. Applicable to multiple layers. Also, any layer can be specified and applied.

  Further, the present invention can be applied to a tire cord group constituted by bundling a plurality of tire cords constituted by a plurality of classification layers or a tire cord group constituted by twisting a plurality. In other words, by defining a tire cord composed of a plurality of classification layers as a single layer, the present embodiment is configured by tying a tire cord group composed of a plurality of tire cords composed of a plurality of classification layers or a plurality of twists. It can be applied to the configured tire cord group.

  In FIG. 37, as an example of the three-dimensional model created in accordance with the above process, the innermost layer 42, the intermediate layer 44, and the outermost layer 46 each have filaments 48 in the same twist direction and filaments 48 in different twist directions between the layers. A three-dimensional model 64 of the layered tire cord 40 is shown. FIG. 38 shows an example of a three-dimensional model 65 of the tire cord 41 formed by bundling the three-layer tire cords 40 shown in FIG.

  The three-dimensional model 64 shown in FIG. 37 is a three-dimensional model in contact between the layers, and the three-dimensional model 65 shown in FIG. 38 is in contact with the circumscribed shape (cord surface) of the third layer (outermost layer 46) of each tire cord 40. Since the elements are defined, a three-dimensional model in which three tire cords 40 of three-layer twist are brought into contact with each other. Modeling rubber or the like outside the tire cord 40 and the tire cord 41 described above is very easy because it only creates an element outside the circle.

  Although not shown, a three-dimensional model can be created for a spiral tire cord by the same processing as described above.

1 is a schematic diagram of a personal computer for creating a tire code analysis model and performing a tire behavior simulation using the created analysis model according to an embodiment of the present invention. FIG. It is a flowchart which shows the flow of a process of the tire behavior analysis program concerning this Embodiment. It is a flowchart which shows the flow of a tire model creation process. It is a diagram which shows a tire cross-section model. It is a flowchart which shows the flow of the process which produces the analysis model of a tire cord concerning embodiment of this invention. It is a flowchart which shows the flow of the two-dimensional model creation process of the tire cord which concerns on 1st Embodiment. It is a flowchart which shows the flow of the 3-dimensional model creation process of the tire cord which concerns on 1st Embodiment. It is explanatory drawing of modeling of the tire cord of a single twist. It is an image figure which shows the filament layer of a tire cord. FIG. 6 is an explanatory diagram of modeling of the innermost layer 42 of the tire cord, where (A) is an element-divided filament, (B) is an element-divided filler, and (C) is a constraining element 52 defined on a circumscribed circle 50. Yes. FIG. 5 is an explanatory diagram for modeling the intermediate layer 44 of the tire cord, in which (A) is an element-divided filament, (B) is an element-divided filler, and (C) is a constraining element 58 defined on a circumscribed circle 56. Yes. It is an image figure which shows a two-dimensional model, (A) has shown the tire cord of 3 layers, (B) has shown the tire cord of 2 layers. It is an image figure showing a tire cord constituted by bundling three tire cords of three layers. It is an image figure which shows the three-dimensional model about an innermost layer, (A) shows only a filament and (B) has shown what provided the filler around the filament. It is an image figure which shows the three-dimensional model about an intermediate | middle layer, (A) shows only a filament and (B) has shown what provided the filler around the filament. It is an image figure which shows an example of the tire code | cord | chord 3D modeled to the 2nd layer. It is an image figure which shows an example of the tire code | cord | chord 3D modeled to the 3rd layer. It is an image figure which shows the mode of a deformation | transformation of the element of a buffer layer. It is an image figure which shows the three-dimensional model before and behind a deformation | transformation concerning an Example, (A) is a three-dimensional model before a deformation | transformation, (B) is a three-dimensional model after a deformation | transformation. It is an image figure which shows an example of the tire cord which bundled three things which twisted and bundled two layers of filaments. It is a flowchart which shows the flow of the 2-dimensional model creation process of the tire cord which concerns on 2nd Embodiment. It is a flowchart which shows the flow of the three-dimensional model creation process of the tire code which concerns on 2nd Embodiment. FIG. 6 is an explanatory diagram of modeling of the innermost layer 42 of the tire cord, where (A) is an element-divided filament, (B) is an element-divided filler, and (C) is a constraining element 52 defined on a circumscribed circle 50. Yes. FIG. 6 is an explanatory diagram for modeling the intermediate layer 44 of the tire cord, in which (A) is an element-divided filament, (B) is an element-divided filler, and (C) is a constraining element 58 defined on a circumscribed circle 58. Yes. It is an image figure which shows a two-dimensional model, (A) has shown the tire cord of 3 layers, (B) has shown the tire cord of 2 layers. It is an image figure showing a tire cord constituted by bundling three tire cords of three layers. It is explanatory drawing of a restraint element. It is an image figure which shows an example of the tire code of the three-dimensional model created according to the process of 2nd Embodiment. It is an image figure showing an example of a three-dimensional model of a tire cord formed by bundling three tire cords. It is a flowchart which shows the flow of the two-dimensional model creation process of the tire cord which concerns on 3rd Embodiment. It is a flowchart which shows the flow of the three-dimensional model creation process of the tire code which concerns on 3rd Embodiment. FIG. 5 is an explanatory diagram of modeling of the innermost layer 42 of the tire cord, where (A) is an element-divided filament, (B) is an element-divided filler, and (C) is a contact element 52 defined on a circumscribed circle 50. Yes. FIG. 5 is an explanatory diagram of modeling of the intermediate layer 44 of the tire cord, where (A) is an element-divided filament, (B) is an element-divided filler, and (C) is a contact element 58 defined by a circumscribed circle 58. Yes. It is an image figure which shows a two-dimensional model, (A) has shown the tire cord of 3 layers, (B) has shown the tire cord of 2 layers. It is an image figure showing a tire cord constituted by bundling three tire cords of three layers. It is explanatory drawing of a contact element. It is an image figure which shows an example of the tire code of the three-dimensional model created according to the process of this embodiment. It is an image figure showing an example of a three-dimensional model of a tire cord formed by bundling three tire cords.

Explanation of symbols

10 keyboard 12 computer main body 20 tire 40, 41 tire cord 42 innermost layer 44 intermediate layer 46 outermost layer 48 filament 50 circumscribed circle 52, 58, 59 constraining element 53, 60, 61 contact element 54 inscribed circle 56 circumscribed circle 57 buffer layer

Claims (16)

An analysis model creation method for a tire code that constitutes a part of a tire model used to calculate a tire corresponding to a numerical calculation model,
When the tire cord is formed by bundling a plurality of filament elements while twisting them in a predetermined direction and is composed of a plurality of classification layers from the center to the outside corresponding to the twist direction of the filament elements, Defining, for the inner first layer, a first two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction;
Forming the first two-dimensional region by dividing the first two-dimensional region into predetermined dividing elements that can be numerically calculated while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
Defining, for the second layer outside the first layer, a second two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction;
Forming the second layer by dividing the second two-dimensional region by a predetermined dividing element that can be numerically calculated while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
Including
At least one of the first two-dimensional region and the second two-dimensional region is composed of each region of a filament element and a filler, and the step of defining the at least one two-dimensional region includes the at least one of the two-dimensional regions. A method for creating an analysis model of a tire code, characterized in that it is a step of defining an element so as not to be created inside an inscribed circle in a two-dimensional region and a filler not in contact with the circumscribed circle. The step of defining the second two-dimensional region includes at least a filament element cross-sectional shape in a direction intersecting a longitudinal direction with respect to the second layer outside the first layer, and a buffer between the first layer and the first layer. The tire cord analysis model creation method according to claim 1, wherein the second two-dimensional region is defined such that a layer is formed. The tire code analysis model creation method according to claim 2, further comprising a step of dividing the buffer layer into predetermined division elements capable of numerical calculation. An outer peripheral node of the first layer and an inner peripheral node of the buffer layer at a position corresponding to the node, and an inner peripheral node of the second layer and an outer node of the buffer layer at a position corresponding to the node The tire code analysis model creation method according to claim 3, further comprising a step of setting and associating at least one of the above and a constraint condition for constraint so as not to move relative to each other. An outer peripheral node of the first layer and an inner peripheral node of the buffer layer at a position corresponding to the node, and an inner peripheral node of the second layer and an outer node of the buffer layer at a position corresponding to the node The tire code analysis model creation method according to claim 3, further comprising a step of setting and associating contact conditions that define restrictions on the relative movement of each of the tire code and the contact condition. The third layer outside the second layer includes at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction, and a buffer layer is formed between the third layer and the second layer. A process of setting
Forming the third layer by dividing the third two-dimensional region by a predetermined dividing element capable of numerical calculation while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
The tire cord analysis model creation method according to any one of claims 2 to 5, further comprising: The tire cord analysis model creation method according to claim 2, further comprising a step of modeling the buffer layer by a meshless method. 8. The tire cord analysis model creation method according to claim 7 , wherein the meshless method is a free mesh method or an element free Galerkin method. Setting a constraint element on the outer periphery of the first two-dimensional region;
Setting a constraining element on at least the inner periphery of the second two-dimensional region;
Forming the second layer by dividing the second two-dimensional region by a predetermined dividing element that can be numerically calculated while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
The constraint element on the outer periphery of the first layer, the inner periphery element of the second layer at a position corresponding to the constraint element, the constraint element on the inner periphery of the second layer, and the first element at the position corresponding to the constraint element. A step of setting and associating a constraint condition that restrains each of the elements on the outer periphery of the first layer from moving relative to each other;
The tire cord analysis model creation method according to claim 1, further comprising: The tire according to claim 9, wherein the restraining element is set on at least a part of a peripheral surface, and the association is at least a part of a peripheral surface corresponding to the at least part of the surface. Code analysis model creation method. Setting a constraint element on the outer periphery of the second two-dimensional region;
Setting a third two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction for an outer third layer adjacent to the second layer;
Setting a constraining element on at least the inner periphery of the third two-dimensional region;
Forming the third layer by dividing the third two-dimensional region by a predetermined dividing element capable of numerical calculation while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
An outer peripheral restraining element of the second layer, an inner peripheral element of the third layer at a position corresponding to the restraining element, an inner peripheral restraining element of the third layer, and the first of the position corresponding to the restraining element. A step of setting and associating a constraint condition for restraining the two layers of outer peripheral elements from moving relative to each other;
The tire code analysis model creation method according to claim 9 or 10, further comprising: Setting a contact element on at least one of an outer periphery of the first two-dimensional region and an inner periphery of the second two-dimensional region;
Corresponding to the set contact element, the outer peripheral contact element of the first layer, the inner peripheral element of the second layer in contact with the contact element, and the inner peripheral contact element of the second layer and the contact element Setting and associating at least one of the outer peripheral elements of the first layer in contact with each other with a contact condition that defines a restriction on relative movement between the elements;
The tire cord analysis model creation method according to claim 1, further comprising: The tire according to claim 12, wherein the contact element is set on at least a part of a peripheral surface, and the association is at least a part of a peripheral surface corresponding to the at least part of the surface. Code analysis model creation method. Setting a third two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction for an outer third layer adjacent to the second layer;
Forming the third layer by dividing the third two-dimensional region by a predetermined dividing element capable of numerical calculation while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
Setting contact elements on at least one of an outer periphery of the second two-dimensional region and an inner periphery of the third two-dimensional region;
The contact element on the outer periphery of the second layer corresponding to the set contact element, the inner periphery element of the third layer in contact with the contact element, and the contact element on the inner periphery of the third layer and the contact element Setting and associating at least one of the elements on the outer periphery of the second layer in contact with each other with a contact condition that defines a restriction on relative movement between the elements;
The tire code analysis model creation method according to claim 12 or 13, further comprising: An analysis model creation device for a tire code constituting a part of a tire model used for calculating a tire corresponding to a numerical calculation model,
When the tire cord is formed by bundling a plurality of filament elements while twisting them in a predetermined direction and is composed of a plurality of classification layers from the center to the outside corresponding to the twist direction of the filament elements, A first defining means for defining a first two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction with respect to the inner first layer;
First forming means for forming a first layer divided into predetermined dividing elements capable of numerical calculation while twisting the first two-dimensional region in the longitudinal direction while twisting in the corresponding twisting direction;
A second defining means for defining a second two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction with respect to the second layer outside the first layer;
A second forming means for forming a second layer by dividing the second two-dimensional region by a predetermined dividing element capable of numerical calculation while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
Including
At least one of the first two-dimensional region and the second two-dimensional region is composed of each region of a filament element and a filler, and at least one of the first definition means and the second definition means is at least one of the first definition means and the second definition means. An apparatus for creating an analysis model of a tire code, characterized in that it is defined so that no element is created inside a filler that is not in contact with an inscribed circle and a circumscribed circle in the two-dimensional region. A computer for creating an analysis model of a tire code constituting a part of a tire model used for calculating a tire corresponding to a numerical calculation model;
When the tire cord is formed by bundling a plurality of filament elements while twisting them in a predetermined direction and is composed of a plurality of classification layers from the center to the outside corresponding to the twist direction of the filament elements, A first defining means for defining a first two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction with respect to the inner first layer;
First forming means for forming a first layer divided into predetermined dividing elements capable of numerical calculation while twisting the first two-dimensional region in the longitudinal direction while twisting in the corresponding twisting direction;
A second defining means for defining a second two-dimensional region including at least a filament element cross-sectional shape in a direction intersecting the longitudinal direction with respect to the second layer outside the first layer;
A second forming means for forming a second layer by dividing the second two-dimensional region by a predetermined dividing element capable of numerical calculation while three-dimensionally developing in the longitudinal direction while twisting in the corresponding twisting direction;
As well as
At least one of the first two-dimensional region and the second two-dimensional region is composed of each region of a filament element and a filler, and at least one of the first definition means and the second definition means is at least one of the first definition means and the second definition means. A tire code analysis model creation program that functions as a means for defining an element so as not to be created inside a filler that is not in contact with the inscribed circle and circumscribed circle in the two-dimensional region.

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