JP4989236B2 - Structure model creation device, structure model creation method, and structure model creation program - Google Patents

Description

  The present invention relates to a structure model creation apparatus, a structure model creation method, and a structure model creation program. More specifically, a structure model for analyzing the performance of a toroidal structure by a finite element method or the like. The present invention relates to a structure model creation device, a structure model creation method, and a structure model creation program.

  For toroidal structures that rotate about the axis of rotation, especially pneumatic tires, solid tires, tire tubes, etc., even if the shape is axisymmetric with respect to the axis of rotation, the type of use is non-axial Receive a symmetrical force. For this reason, when performing the numerical analysis of the toroidal structure as described above, it is essential to use a three-dimensional model.

  When creating a three-dimensional model of a toroidal structure, a method for directly modeling the three-dimensional structure of the structure and a cross section when the structure is first cut by a plane including the rotation axis of the structure was modeled. There is a method of creating a three-dimensional model by creating a two-dimensional cross-sectional model and expanding it in the circumferential direction of the structure.

Conventionally, simulations using the finite element method, boundary element method, finite volume method, etc. are performed using the three-dimensional model created in this way, and physical quantities such as displacement, velocity, stress, force, and strain are calculated. It is made from. For example, Patent Literature 1 to Patent Literature 3 disclose a tire model creation method for simulating tire performance by a finite element method.
Japanese Patent No. 3314082 JP 2006-199155 A JP 2006-1361 A

  However, the toroidal structure does not always have the same cross section in the entire circumferential direction. For example, in the case of a tire, in order to model a tire in which grooves extending in a direction orthogonal to the tire equatorial plane exist intermittently in the circumferential direction, for example, a tire without grooves is modeled three-dimensionally and further specified. It is necessary to make modifications such as forming grooves by deleting some elements from the cross section.

  If only a single two-dimensional cross-sectional model can be used as in the past, it is necessary to perform editing operations such as adding and deleting elements individually after creating the three-dimensional model, making modeling work complicated Met.

  The present invention has been made to solve the above-described problem, and is a structure model creation apparatus and structure model creation capable of easily creating a three-dimensional model of a toroidal structure having different shapes of cross sections. It is an object to provide a method and a structure model creation program.

  In order to achieve the above object, a structure model creation device according to a first aspect of the present invention is configured to divide a cross section of the structure in a plane including a rotation axis of a toroidal structure into a plurality of finite elements. Two-dimensional cross-section model setting means for setting a plurality of types of two-dimensional cross-section models; arrangement setting means for setting the arrangement of a plurality of types of two-dimensional cross-section models; And creating means for creating a three-dimensional model of the structure by expanding in the circumferential direction of the structure.

  According to this invention, the two-dimensional cross-section model setting means sets a plurality of types of two-dimensional cross-section models in which the cross section of the structure on the plane including the rotation axis of the toroidal structure is divided into a finite number of elements. The two-dimensional section model may be created, or a two-dimensional section model created in advance may be stored in the storage means and selected from these. In addition, the toroidal structure is not limited as long as it rotates with respect to a predetermined rotation axis, and is not necessarily closed in an annular shape, and may be partially opened.

  Then, by setting the arrangement of a plurality of types of two-dimensional cross-section models by the arrangement setting means, and by developing the plurality of types of two-dimensional cross-section models in the circumferential direction of the structure according to the arrangement set by the arrangement setting means. Create a three-dimensional model of a toroidal structure.

  In this way, since a two-dimensional cross-sectional model of a plurality of types of toroidal structures is set, a three-dimensional model is created by setting these arrangements in a desired order and developing them in the circumferential direction of the structure. A three-dimensional model of a structure having various shapes can be easily created.

  In addition, as described in claim 2, the editing unit that edits the two-dimensional section model, and the creation unit include a three-dimensional model correcting unit that corrects the three-dimensional model based on an editing result by the editing unit. It is good also as a structure further provided with these.

  In this case, as described in claim 3, the editing unit may perform at least one of addition, deletion, partial change, and change of the arrangement of the two-dimensional cross-sectional model. Good.

  According to a fourth aspect of the present invention, the apparatus may further include display means for displaying the two-dimensional cross-sectional model, the arrangement of the two-dimensional cross-sectional model, and the three-dimensional model.

According to a fifth aspect of the present invention, there is provided a structure model creation method in which a computer uses a plurality of two-dimensional section models obtained by dividing a section of the structure on a plane including a rotation axis of a toroidal structure into a plurality of finite elements. By setting the type, setting the arrangement of a plurality of types of two-dimensional cross-sectional models, and expanding the plurality of types of two-dimensional cross-sectional models in the circumferential direction of the structure according to the arrangement set by the arrangement setting means A three-dimensional model is created.

According to this invention, a computer sets a two-dimensional cross-sectional model of a plurality of types of toroidal structures, sets these arrangements in a desired order, and develops them in the circumferential direction of the structure, thereby generating a three-dimensional model. Therefore, a three-dimensional model of a structure having various shapes can be easily created.

  The program for creating a structure model according to claim 6 sets a plurality of types of two-dimensional cross-sectional models in which a cross section of the structure on a plane including the rotation axis of the toroidal structure is divided into a finite number of elements. A step of setting an arrangement of a plurality of types of two-dimensional cross-sectional models, and expanding the plurality of types of two-dimensional cross-section models in the circumferential direction of the structure according to the arrangement set by the arrangement setting means And a step of creating a three-dimensional model of the object.

  According to the present invention, a two-dimensional cross-sectional model of a plurality of types of toroidal structures is set, a three-dimensional model is created by setting these arrangements in a desired order and developing them in the circumferential direction of the structure. Therefore, a three-dimensional model of a structure having various shapes can be easily created.

  As described above, according to the present invention, it is possible to easily create a three-dimensional model of a toroidal structure having cross sections having different shapes.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an outline of a personal computer for creating a tire model of a pneumatic tire and predicting performance as an example. This personal computer includes a keyboard 10 for inputting data and the like, a computer main body 12 for creating a three-dimensional tire model and predicting performance according to a pre-stored processing program, calculation results and various settings by the computer main body 12 A CRT 14 for displaying a screen and the like, and a mouse 16 for performing an operation of moving a cursor displayed on the CRT to a desired position, selecting, deselecting, or dragging a menu item or object at the cursor position. It is composed of

  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 a processing routine described later can be read from and written to the flexible disk FD using, for example, an FDU. Therefore, 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, the processing program may be stored (installed) in a mass storage device (not shown) such as a hard disk device provided in the computer main body 12 and executed. As recording media, there are optical discs such as CD-ROM and DVD-ROM, and magneto-optical discs such as MD and MO. When these are used, a CD-ROM device or DVD-ROM is used instead of or in addition to the FDU. A ROM device, MD device, MO device, or the like may be used.

  The hard disk of the computer main body 12 stores a tire model creation and tire performance analysis program, which will be described later, and various parameters and data necessary for the execution thereof.

  Next, as an operation of the present embodiment, a tire model creation and tire performance analysis program processing routine executed by the computer main body 12 will be described with reference to a flowchart shown in FIG.

  In step 100, a plurality of types of two-dimensional tire cross-sectional models are created. This two-dimensional cross-sectional model is a cross-sectional model when a tire is cut on a plane including a rotation axis of the tire (a plane including a direction orthogonal to the circumferential direction of the tire).

  In creating the two-dimensional section model, first, the outer shape of the two-dimensional section is set. In this case, a screen for creating a two-dimensional cross-sectional model may be displayed on the CRT 14 and the external shape of the two-dimensional cross-section may be designated by the user operating the mouse 16 or the keyboard 10. Data of the external shape of the two-dimensional cross section may be stored in advance in a hard disk of the computer main body 12 and the external shape of the two-dimensional cross section may be selected from these.

  In addition to setting the external shape of the two-dimensional cross section, various parameters (for example, Young's modulus, etc.) relating to the tire material and the like can be set. This may be input directly by the user, or may be selected by the user from a plurality of types of parameters, or predetermined parameters may be set.

  Then, after setting the external shape of the two-dimensional cross section and various parameters related to the tire material, a two-dimensional cross-sectional model for numerical analysis is created. The creation of this 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 two-dimensional section model to be created includes data related to the node of each element when it is divided into a plurality of elements (mesh) by element division corresponding to the finite element method (FEM), for example, mesh division.

  This element division means dividing the tire into a large number of (finite) elements (small parts). The element can be, for example, a tetrahedral element, a pentahedral element, a hexahedral element, or the like. In this embodiment, the element is divided into hexahedral elements as an example. After performing numerical calculation for each element and calculating all the elements, the entire response can be obtained by combining all the elements. The numerical analysis method is not limited to the finite element method, and other known numerical analysis methods such as a difference method, a finite volume method, and a discrete element method (DEM) may be used.

  A plurality of types of two-dimensional cross-section models are created as described above. Examples of the created two-dimensional cross-sectional model are shown in FIGS. As shown in FIG. 3, the two-dimensional section model 20 is a model composed of a plurality of elements 20A, and as shown in FIG. 4, the two-dimensional section model 22 is a model composed of a plurality of elements 22A.

  The created two-dimensional section models 20 and 22 are displayed in sub-windows 26 and 28 on the tire model creation screen 24 displayed on the CRT 14, for example, as shown in FIG.

  As shown in FIG. 4, the two-dimensional section model 22 has a shape in which a part of the upper part of the two-dimensional section model 20 shown in FIG. In this case, the user can create the two-dimensional section model 22 by copying the two-dimensional section model 20 on the tire model creation screen 24 shown in FIG. . Thereby, it is not necessary to create the two-dimensional section model 22 from the beginning, and convenience can be improved.

  In the above description, a case where a plurality of types of two-dimensional cross-sectional models are created has been described. However, a plurality of types of two-dimensional cross-sectional models created in advance are stored in advance in the hard disk or the like of the computer main body 12, and a desired plurality of them can be selected. The two-dimensional section model may be selected by the user.

  In step 102, the arrangement of the two-dimensional section model created in step 100, that is, the arrangement order of the two-dimensional section model in the tire circumferential direction is set. For example, in the subwindow 30 on the tire model creation screen 24 shown in FIG. 5, the user arranges the two-dimensional section model 20 (two-dimensional section model A) and the two-dimensional section model 22 (two-dimensional section model B) (the tire The order in the circumferential direction) can be specified. FIG. 5 shows an example in which the two-dimensional section models A and B are set to be alternately arranged.

  In step 104, a plurality of types of two-dimensional cross-sectional models are developed in the tire circumferential direction in accordance with the arrangement set in step 102 to create a tire three-dimensional model. An example of the three-dimensional model created in this way is shown in FIG. A three-dimensional model 32 shown in FIG. 6 is created by setting the two-dimensional cross-sectional models 20 and 22 shown in FIGS. 3 and 4 to be alternately arranged. The created three-dimensional model 32 is displayed in a subwindow 34 on the tire model creation screen 24 shown in FIG. Each sub-window can change the display position and the size of the window, delete or call the window, etc. as necessary.

  Conventionally, for example, one type of two-dimensional cross-sectional model 20 as shown in FIG. 3 could be developed in the circumferential direction of the tire to create a three-dimensional model 36 as shown in FIG. In the present embodiment, a plurality of types of two-dimensional cross-sectional models can be created, and the arrangement of these tires in the circumferential direction can be freely set. Therefore, a three-dimensional model of a tire having grooves of various patterns Can be easily created. Therefore, it is possible to easily examine the tire design particularly in the initial stage, and to improve the design efficiency.

  In step 106, it is determined whether or not an instruction to edit the three-dimensional model of the created tire is given on the tire model creation screen 24. If the user instructs to edit, the process proceeds to step 108; Proceeds to step 110.

  In step 108, an editing process instructed by the user is executed. Here, the editing refers to, for example, partial change (correction), addition, deletion, change of arrangement of the two-dimensional section model, partial change of the three-dimensional model, and the like.

  In the partial change of the two-dimensional cross-sectional model, for example, a part of the two-dimensional cross-sectional model 20 can be changed to create a two-dimensional cross-sectional model 38 as shown in FIG. In the two-dimensional section model 38 shown in FIG. 8, two grooves 40 are provided. In this case, the user designates deletion of the element corresponding to the groove 40 on the sub-window 26 of the tire model creation screen 24 shown in FIG. 5, so that the two-dimensional cross-sectional model 20 shown in FIG. The two-dimensional section model 38 shown can be modified. In this case, the data representing the two-dimensional section model 38 can be created by deleting the data of the element corresponding to the groove 40 from the data representing the two-dimensional section model 20. Note that it is also possible to create the two-dimensional cross-sectional model 38 shown in FIG. 8 by adding an element to the central portion of the groove 42 of the two-dimensional cross-sectional model 22 shown in FIG. 4 instead of deleting the element.

  When the two-dimensional section model 22 is corrected to the two-dimensional section model 38 as shown in FIG. 8 and arranged alternately with the two-dimensional section model 20 as described above, a three-dimensional model 44 as shown in FIG. 9 is created. can do.

  Further, in the partial change of the two-dimensional section model, it is possible not only to add and delete elements, but also to change the shape of the elements by changing the positions of the nodes of the elements.

  In addition, in the addition of the two-dimensional section model, a new two-dimensional section model is created by the same processing as in step 100, or a two-dimensional section model stored in advance in the hard disk of the computer main body 12 is selected. A two-dimensional section model can be added. For example, when a two-dimensional section model 46 as shown in FIG. 10 is added and the two-dimensional section models 20, 38, 20, 46 are set in this order, a three-dimensional model 48 as shown in FIG. 11 is created. can do.

  In the deletion of the two-dimensional section model, for example, the two-dimensional section model can be deleted by designating the two-dimensional section model to be deleted in the sub-window 30 of the tire model creation screen 24 shown in FIG.

  After editing the two-dimensional cross-sectional model, the arrangement of the two-dimensional cross-sectional model is set by the same process as in step 102, and the two-dimensional cross-sectional model is developed in the tire circumferential direction by the same process as in step 104. As a result, the three-dimensional model can be automatically corrected simply by correcting the two-dimensional section model, and the three-dimensional model can be easily corrected.

  Instead of correcting the two-dimensional section model, the three-dimensional model may be corrected directly by deleting or adding elements to the three-dimensional model, changing the element shape, or the like. In this case, the user designates element deletion or addition, element shape change, or the like on the subwindow 34 of the tire model creation screen 24 shown in FIG. As a result, the three-dimensional model can be corrected directly.

  In step 110, it is determined whether or not the user gives an instruction to execute the performance analysis of the created three-dimensional model. If there is an instruction, the process proceeds to step 112. If there is no instruction, the process proceeds to step 120. Transition.

  In step 112, the road surface state is input together with the road surface model. In this step 112, the road surface is modeled and input to set the modeled road surface to an actual road surface state. The road surface shape is divided into elements to model the road surface, and the friction coefficient μ of the road surface is calculated. The road surface condition is input by selecting and inputting. That is, depending on the road surface condition, there is a friction coefficient μ of the road surface corresponding to a dry state, a wet state, on ice, on snow, non-paved, etc., so by selecting an appropriate value for the friction coefficient μ, the actual road surface state can be changed. Can be reproduced.

  In this way, when the road surface condition is input, the boundary condition is set in the next step 114. The boundary condition is set by applying an internal pressure, a load, a displacement, a rotational speed, a torque, or the like to the tire model, or a straight traveling speed or a road surface speed.

  In step 116, tire deformation is calculated by the finite element method under the boundary conditions set in step 114, and tire distortion and the like are simulated.

  In step 118, the simulation result based on the tire deformation calculation in step 116, for example, the tire shape or the like is displayed on the CRT 14.

  In step 120, it is determined whether or not the user has instructed the re-creation of the tire model. If the re-creation has been instructed, the process returns to step 100 to repeat the same processing as described above. On the other hand, if re-creation is not instructed, the process proceeds to step 122.

  In step 122, it is determined whether or not the user has instructed to end the creation and analysis of the tire model. If there is no end instruction, the process returns to step 106 to repeat the same processing as described above, and has received an end instruction. If so, this routine is terminated.

  As described above, in the present embodiment, a two-dimensional cross-sectional model of a plurality of types of tires is created, and a three-dimensional model of the tire is created by setting these arrangements in a desired order and developing them in the circumferential direction of the tire. Therefore, a three-dimensional model of a tire having various patterns of grooves can be easily created. Therefore, particularly in the initial stage of tire design, it is possible to efficiently create and analyze tire models having various shapes.

  In the present embodiment, the case where a three-dimensional model of a pneumatic tire is created has been described. However, the present invention is not limited to this, and a toroidal structure that rotates with respect to a rotating shaft, for example, a solid tire, a tire tube, and the like. The present invention is applicable.

It is the schematic of the personal computer for implementing preparation of a tire model and performance prediction of a tire. It is a flowchart of a tire model creation and tire performance analysis program. It is sectional drawing which shows an example of the two-dimensional cross-section model of a tire. It is sectional drawing which shows an example of the two-dimensional cross-section model of a tire. It is a figure which shows an example of a tire model creation screen. It is a perspective view which shows an example of the three-dimensional model of a tire. It is a perspective view which shows an example of the three-dimensional model of a tire. It is sectional drawing which shows an example of the two-dimensional cross-section model of a tire. It is a perspective view which shows an example of the three-dimensional model of a tire. It is sectional drawing which shows an example of the two-dimensional cross-section model of a tire. It is a perspective view which shows an example of the three-dimensional model of a tire.

Explanation of symbols

10 Keyboard 12 Computer body 14 CRT
16 mice

Claims (6)

Two-dimensional cross-section model setting means for setting a plurality of types of two-dimensional cross-section models obtained by dividing a cross section of the structure on a plane including the rotation axis of the toroidal structure into a plurality of finite elements;
Arrangement setting means for setting the arrangement of a plurality of types of two-dimensional section models;
Creating means for creating a three-dimensional model of the structure by expanding the plurality of types of two-dimensional cross-sectional models in the circumferential direction of the structure according to the arrangement set by the arrangement setting means;
A structure model creation device characterized by comprising: Editing means for editing the two-dimensional section model;
The creating means includes a three-dimensional model correcting means for correcting the three-dimensional model based on an editing result by the editing means;
The structure model creating apparatus according to claim 1, further comprising:   3. The structure model creating apparatus according to claim 2, wherein the editing unit performs at least one of addition, deletion, partial change, and change of the arrangement of the two-dimensional section model. .   4. The display device according to claim 1, further comprising a display unit configured to display at least one of the two-dimensional cross-sectional model, the arrangement of the two-dimensional cross-sectional model, and the three-dimensional model. The structure model creation device described. Computer
Setting a plurality of types of two-dimensional cross-sectional models in which the cross section of the structure on the plane including the rotation axis of the toroidal structure is divided into a finite number of elements,
Set the arrangement of multiple types of 2D section models,
A structure model creation method for creating a three-dimensional model of the structure by developing the plurality of types of two-dimensional cross-sectional models in a circumferential direction of the structure according to the arrangement set by the arrangement setting means. Setting a plurality of types of two-dimensional cross-sectional models obtained by dividing a cross section of the structure in a plane including the rotation axis of the toroidal structure into a plurality of finite elements;
Setting the arrangement of a plurality of types of two-dimensional section models;
Creating a three-dimensional model of the structure by expanding the plurality of types of two-dimensional cross-sectional models in the circumferential direction of the structure according to the arrangement set by the arrangement setting means;
A structure model creation program for causing a computer to execute a process including:

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