JP6214972B2 - FEM analysis model generation apparatus, method, and computer program - Google Patents

Description

  The present invention relates to an FEM analysis model generation apparatus, method, and computer program used for FEM (Finite Element Method) analysis of pneumatic tires and other structures.

  The FEM analysis model is a mesh model in which a structure to be analyzed is divided into a plurality of elements, and members, member boundary lines, elements, nodes, material properties of the members, and the like constituting the structure are defined. The model for FEM analysis is generally generated manually.

  Product development is often designed by changing the product size or changing the shape of a part of the product. In this case, it is necessary to generate FEM analysis models for the product one by one even if the sizes are different or only some shapes are different. In this case, for example, when products of three types of sizes are to be analyzed, it is necessary to generate three FEM analysis models, which takes a long time for development and increases development costs.

  As one means for reducing the time required for development, in Patent Document 1, when changing the shape by moving an element of an existing FEM model, the shape of surrounding elements is changed in conjunction with the movement of the element. Is disclosed.

JP 2006-199155 A

  However, even if the technique of Patent Document 1 is used, it is necessary to manually move a plurality of nodes and elements defined in the existing FEM model so that a desired shape is obtained. Although it may be possible to reduce the development time somewhat compared to the case of generating an FEM model from scratch, all the nodes and elements required for the shape change must be moved manually. Development takes time.

  The inventor of the present invention pays attention to the fact that there is often drawing data in which the object to be analyzed is represented by member boundary lines (vector data, etc.) such as two-dimensional CAD data in the product design scene. I got a new idea of effectively using.

  The present invention has been made based on such a new idea, and an object thereof is to provide an FEM analysis model generation apparatus, method, and computer program that can reduce development time and development cost. It is.

  In order to achieve the above object, the present invention takes the following measures.

  That is, the FEM analysis model generation apparatus of the present invention is a new model generation unit that generates a new model having the member boundary line data based on the drawing data representing the structure to be newly modeled by the member boundary line. A member recognition unit that recognizes a closed region surrounded by the member boundary line in the new model as one member, a predetermined reference line common to the new model and the existing FEM model, and a contour line of the structure A member matching unit that associates the member of the new model with the member of the existing FEM model based on the arrangement order, and the member boundary line of the new model based on the arrangement order along the predetermined reference line and the outline line of the structure A boundary line matching unit that associates a member boundary line of the existing FEM model with the member in the new model. In copying the physical property data definition part that defines the same material physical property data as the material physical property of the corresponding member in the FEM model and the node on the member boundary line in the existing FEM model onto the corresponding member boundary line in the new model, A first-type node copying unit that copies the node at a position corresponding to a ratio of a length of the member boundary line to a length from the end of the member boundary line to the node; and on the member boundary line in the existing FEM model Depending on the ratio of the length of the virtual line to the length from the end of the virtual line to the node when copying the node on the virtual line connecting the nodes to the corresponding virtual line in the new model A second-type node copying unit that copies the node at a predetermined position.

  The method for generating a model for FEM analysis according to the present invention includes a step of generating a new model having data of the member boundary line based on drawing data representing a structure to be newly modeled by a member boundary line, and the new model Recognizing as a single member a closed region surrounded by the member boundary line, and based on a predetermined reference line common to the new model and an existing FEM model and an arrangement order along an outline line of the structure, A member boundary line of the new model and a member boundary line of the existing FEM model based on the step of associating the model member with the member of the existing FEM model, and the arrangement order along the predetermined reference line and the outline line of the structure And the member of the corresponding member in the existing FEM model with respect to the member in the new model In the step of defining the same material property data as the physical properties, and copying the node on the member boundary line in the existing FEM model onto the corresponding member boundary line in the new model, from the end of the member boundary line to the node A step of copying the node to a position corresponding to a ratio of a length of the member boundary line to a length; and a node on a virtual straight line connecting the nodes on the member boundary line in the existing FEM model. Copying on the corresponding virtual straight line in step (b), copying the node to a position corresponding to the ratio of the length of the virtual straight line to the length from the end of the virtual straight line to the node.

  The predetermined reference line is a line common to the existing model and the new model, and may be a line that penetrates the structure. For example, the center line of a structure is mentioned.

  In this way, using the drawing data in which the structure to be newly modeled is represented by the member boundary line, the material of the member defined in the existing FEM model is created by associating the new model with the member and the member boundary line of the existing FEM model. Data of physical properties, nodes and elements are copied so as to match the boundary line of the new model. Therefore, a new model can be generated automatically or semi-automatically, and the model generation time can be greatly reduced and convenience can be improved. At the same time, development costs can be reduced.

  In the apparatus, in order to associate the member and the member boundary line sufficiently and accurately, the member matching unit and the boundary line matching unit are associated with the existing FEM model among the members of the new model. When an unprocessed member is not already associated with the unprocessed member and an adjacent member across the member boundary line, the unprocessed member and the member of the existing FEM model according to the adjacent positional relationship Are preferably associated with each other.

  In the method, in order to sufficiently and accurately associate the member and the member boundary line, the unprocessed member that is not associated with the member of the existing FEM model among the members of the new model Preferably, when a member and an adjacent member across the member boundary line are already associated, the unprocessed member and the member of the existing FEM model are associated with each other according to the adjacent positional relationship. .

  In the apparatus, when a node that is not in either the member boundary line or the virtual line in the existing FEM model is copied to the new model, the position of the node is expressed with reference to a plurality of nodes around the node. A third type node copying unit that converts the normalized coordinates into shape coordinates using a shape function and copies the corresponding nodes to the coordinates calculated by the normalized coordinates and the coordinates of the corresponding nodes in the new model; preferable.

  In the method, when a node that is not on either the member boundary line or the virtual line in the existing FEM model is copied to the new model, the position of the node is expressed with reference to a plurality of nodes around the node. Preferably, the method includes a step of converting the normalized coordinates using a shape function, and copying the nodes to the coordinates calculated from the positions of the corresponding nodes and the normalized coordinates in the new model.

  As a preferred application example of the present invention, the existing FEM model and the newly modeled structure are tires, and the predetermined reference line is a tire equator line.

  In the apparatus, in order to improve the processing speed of associating members and member boundary lines, the existing FEM model and the new model have tire size data, and the member matching unit and the boundary line matching unit are It is preferable to associate the member constituting the bead portion and the member boundary line according to the tire size and a predetermined member shape.

  In the method, the existing FEM model and the new model have data on tire size, and the tire size and the predetermined member shape are determined in order to improve the processing speed of the association between the member and the member boundary line. It is preferable to include a step of associating a member constituting the bead portion and a member boundary line.

  In the present invention, the steps constituting the above method can be specified from the viewpoint of a program. That is, the computer program of the present invention causes the computer to execute each step constituting the above FEM analysis model generation method. By executing this program, the operational effects produced by the above method can be obtained.

The block diagram which shows the production | generation apparatus of the model for FEM analysis of this invention. The figure which shows an example of the existing FEM model in which the node, the element, and the member boundary line were defined. The figure which shows the member of the existing FEM model by hatching. The figure which shows the diagram data showing the structure to model newly. The figure which shows the member of the structure to model newly by hatching. The figure which shows the result of the 1st-2nd member matching process. The figure which shows the result of the 1st-3rd member matching process. Explanatory drawing regarding the process which copies the node on the member boundary line of the existing FEM model to a new model. Explanatory drawing regarding the process which copies the node on the member boundary line of the existing FEM model to a new model. Explanatory drawing regarding the process which copies the node on the virtual straight line which connects the nodes on the member boundary line of the existing FEM model to a new model. Explanatory drawing regarding the process which copies the node on the virtual straight line which connects the nodes on the member boundary line of the existing FEM model to a new model. Explanatory drawing regarding the process which copies the node which is not in either the member boundary line of an existing FEM model, or a virtual straight line to a new model. The flowchart which shows a FEM model production | generation process.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[FEM analysis model generation device]
The FEM analysis model generation apparatus 1 according to the present invention uses the existing FEM model M1 shown in FIG. 2A and the drawing data representing the newly modeled structure shown in FIG. This is an apparatus for generating a model for FEM analysis. The structure shown in FIGS. 2A and 3A is a pneumatic tire. 2A and 3A differ in the shape of the end of the tread portion.

  Specifically, as illustrated in FIG. 1, the apparatus 1 includes an existing FEM model storage unit 10, a drawing data storage unit 11, a new model generation unit 12, a member recognition unit 13, a member matching unit 14, a boundary The line matching unit 15, the physical property data defining unit 16, the first type node copying unit 17, the second type node copying unit 18, and the third type node copying unit 19 are provided. These units 12 to 19 are realized by cooperation of software and hardware by executing a processing routine (not shown) stored in advance by the CPU in an information processing apparatus such as a personal computer having a CPU, a memory, various interfaces, and the like. Is done.

  The existing FEM model storage unit 10 illustrated in FIG. 1 stores an existing FEM model M1 as illustrated in FIGS. 2A and 2B. The FEM model is a mesh model in which the structure to be analyzed is divided into a plurality of elements. The FEM model is composed of members, information on members (including member names and material physical properties), nodes, and nodes. Elements (mesh) are defined and used for FEM analysis. In FIG. 2A, a node is indicated by “◯”, an element constituted by four nodes is indicated by a dotted line, and a member boundary line is indicated by a solid line. In FIG. 2B, members are indicated by hatching, and member boundary lines are indicated by solid lines. In the present embodiment, the FEM analysis model is a tire model, and tire equator line CL (see FIG. 4A), tire size data (for example, rim diameter), boundary conditions, analysis condition data, and the like are set.

  The drawing data storage unit 11 shown in FIG. 1 stores drawing data in which a structure to be newly modeled as shown in FIG. 3A is represented by member boundary lines (such as vector data). In the present embodiment, the drawing data is diagram data representing a tire with a member boundary line, and a straight line or a curve is used as the member boundary line. Various formats can be adopted as the method for expressing the line segment data.

  Data stored in the existing FEM model storage unit 10 and the drawing data storage unit 11 is set by the user via an operation unit (not shown).

  The new model generation unit 12 illustrated in FIG. 1 generates a new model M2 having member boundary data based on the drawing data stored in the drawing data storage unit 11. The new model M2 is a model in which member boundary data indicated by a solid line is defined, but the members, material properties, nodes, and elements of the members are not defined. These pieces of information are defined in the new model M2 by the following units.

  The member recognition unit 13 illustrated in FIG. 1 recognizes a closed region surrounded by a member boundary line in the new model M2 as one member. FIG. 3B is a diagram showing the members recognized in the new model M2 by hatching.

  The member matching unit 14 illustrated in FIG. 1 associates the member of the new model M2 illustrated in FIG. 3B with the member of the existing FEM model M1 illustrated in FIG. 2B. The first member association process executed by the member matching unit 14 is performed based on the arrangement order along a predetermined reference line common to the new model M2 and the existing FEM model M1. The predetermined reference line can be appropriately changed as long as it is a line penetrating the structure. For example, the center line can be mentioned. In this embodiment, as shown in FIG. 4A, since the structure is a tire, the tire equator line CL is used as a predetermined reference line.

  The 2nd member matching process which the member matching part 14 performs is performed based on the arrangement order along the external shape line of a structure (this embodiment tire). If these first and second member association processes are executed, in the case of a tire, most members can be associated as shown in FIG. 4A. In FIGS. 4A and 4B, the hatched member indicates that the member is associated, and the non-hatched member (outlined portion) indicates that the member is not associated (member matching). Show. In the example of FIG. 4A, it can be seen that no association is made with members inside the tire, such as the bead core 20 and the bead filler 21.

  The member matching unit 14 can execute a third member association process. As shown in FIGS. 4A and 4B, the third member association process associates the members constituting the bead portion 2 according to the tire size and the predetermined member shape of the new model M2 and the existing FEM model M1. I do. In this embodiment, the association of the bead core 20 and the bead filler 21 is executed as a member constituting the bead unit 2. The bead core 20 has a feature such as a quadrangle, a polygon such as a hexagon, a circle or an ellipse, and the bead filler 21 has a feature of a triangle. Since the other member of the bead part 2 is plate-shaped, if the position of the bead part 2 can be specified, the bead core 20 and the bead filler 21 can be specified by the characteristics of the member shape. Since the rim diameter can be determined from the information on the tire size, the position of the bead portion 2 can be roughly specified. When the first to third member association processes are executed, the members are associated as shown in FIG. 4B. From this figure, it can be seen that the bead core 20 and the bead filler 21 are associated with each other. In this embodiment, the association of both the bead core 20 and the bead filler 21 is executed, but only one of the associations may be implemented.

  The member matching unit 14 can execute a fourth member association process. As shown in an enlarged view in FIG. 4B, the fourth member association process is performed on the unprocessed member 22 that is not associated with the existing FEM model M1 among the members of the new model M2, and When the adjacent members (23, 24, 25) are already associated with the member boundary line interposed therebetween, the unprocessed member 22 and the member of the existing FEM model M1 are associated with each other according to the adjacent positional relationship. Specifically, adjacent member information is stored when member association is performed in the first to third member association processes. When the third member association process is executed, the unprocessed member 22 that has not been associated is extracted from the new model M2, and the extracted unprocessed member 22 is searched from the adjacent member information. When the unprocessed member 22 is found from the adjacent member information, the members are associated according to the adjacent positional relationship. If the fourth member association method is repeatedly executed, all members can be associated with each other.

  The boundary line matching unit 15 illustrated in FIG. 1 associates the member boundary line of the new model illustrated in FIG. 3A with the member boundary line of the existing FEM model M1 illustrated in FIG. 2A. The boundary line matching unit 15 can execute the first to third boundary line association processes. The first boundary line association process associates the member boundary line of the new model M2 with the member boundary line of the existing FEM model M1 based on the arrangement order along the predetermined reference line (tire equator line CL). The first member association process executed by the member matching unit 14 is common in that the object to be associated is not a member but a member boundary line, and thus detailed description thereof is omitted.

  In the second boundary line association process, the member boundary line of the new model M2 and the member boundary line of the existing FEM model M1 are associated with each other based on the arrangement order along the outer shape line of the structure (the tire in the present embodiment). The second member association process executed by the member matching unit 14 is common in that the object to be associated is not a member but a member boundary line, and thus detailed description thereof is omitted.

  The third boundary line associating process is performed on the boundary lines of the members (the bead core 20 and the bead filler 21) constituting the bead portion 2 according to the tire size and the predetermined member shape of the new model M2 and the existing FEM model M1. Perform the association. The third member association process executed by the member matching unit 14 is common in that the object to be associated is not a member but a member boundary line, and thus detailed description thereof is omitted.

  The physical property data defining unit 16 shown in FIG. 1 uses the correspondence relationship data constructed by the member matching unit 14 to make the material physical property data the same as the material physical property of the corresponding member in the existing FEM model M1 for the member in the new model M2. Define As a result, the material properties of the members of the existing FEM model M1 are copied and defined for all the members of the new model M2.

  As shown in FIG. 5A, the first type node copying unit 17 shown in FIG. 1 copies the node on the member boundary line in the existing FEM model M1 onto the corresponding member boundary line in the new model M2. In the example of FIG. 5A, the existing FEM model M1 is shown in the upper part, and the new model M2 is shown in the lower part. As shown in the figure, the nodes (n1 to n8) on the member boundary line 30 in the existing FEM model M1 are copied onto the corresponding member boundary line 30 'in the new model M2. As shown in FIG. 5B, for example, when the node n7 of the existing FEM model M1 is copied as the node n7 ′ of the new model M2, the node from the end of the member boundary line 30 is used to cope with the change in the shape and size of the member. The node n7 ′ is copied at a position corresponding to the ratio (L2 / L1) of the length L1 of the member boundary line 30 to the length L2 up to n7. Specifically, first, a ratio (L2 / L1) between the length L2 from the end of the member boundary line 30 to the node n7 in the existing FEM model M1 and the length L1 of the member boundary line 30 is calculated. Next, the length (D1) of the corresponding member boundary line 30 ′ in the new model M2 is calculated, and from the end of the member boundary line 30 ′ in the new model M2 to the node n7 ′ based on the ratio (L2 / L1). Is calculated (D2). The node n7 'is copied to the coordinate position satisfying the length (D2). This operation is executed for all the nodes (n1 to n8) on the member boundary line 30. The length here is the length along the line.

  As shown in FIG. 6A, the second-type node copying unit 18 shown in FIG. 1 converts the nodes on the virtual line connecting the nodes on the member boundary line in the existing FEM model M1 to the corresponding virtual line in the new model M2. Copy up. In the example of FIG. 6A, the existing FEM model M1 is shown in the upper part, and the new model M2 is shown in the lower part. As shown in the figure, the nodes (n8 to n11) on the virtual straight line 40 connecting the nodes on the member boundary line in the existing FEM model M1 are copied onto the corresponding virtual straight line in the new model. As shown in FIG. 6B, for example, when the node n9 on the virtual line 40 in the existing FEM model M1 is copied as the node n9 ′ on the virtual line 40 ′ in the new model M2, it corresponds to the change in the shape and size of the member. Therefore, as shown in FIG. 6B, the node n9 ′ is copied to a position corresponding to the ratio (L4 / L3) of the length L3 of the virtual straight line 40 to the length L4 from the end of the virtual straight line 40 to the node n9. . Specifically, first, a ratio (L4 / L3) between the length L4 from the end of the virtual straight line 40 to the node n9 and the length L3 of the virtual straight line 40 in the existing FEM model M1 is calculated. Next, the length (D3) of the corresponding virtual straight line 40 ′ in the new model M2 is calculated, and based on the ratio (L4 / L3), the length (D4) from the end of the virtual straight line 40 ′ to the node n9 ′ Is calculated. The node n9 'is copied to the coordinate position satisfying the length (D4). This operation is executed for all nodes (n8 to n11) on the virtual straight line 40. The length here is a linear distance.

FIG. 7 is a view showing the periphery of the bead portion.
As shown in FIG. 7, the third-type node copying unit 19 shown in FIG. 1 copies the node n20 that is not on either the member boundary line or the virtual line in the existing FEM model M1 to the new model M2. First, as shown in the upper part of FIG. 7, the third-type node copying unit 19 first normalizes coordinates (representing the position of the node n20 with reference to a plurality of (four) nodes P1 to P4 around the node n20). r, s) is converted using a shape function. The coordinates of the node n20 are (P _X , P _Y ), and the coordinates of the plurality of nodes P1 to P4 around the node n20 are (P _{1 X} , P _{1 Y} ), (P _{2 X} , P _{2 Y} ), When (P _{3 X} , P _{3 Y} ) and (P _{4 X} , P _{4 Y} ) are used, the normalized coordinates (r, s) are calculated by the following equation.

a _x = (P _{1 X} + P _{2 X} + P _{3 X} + P _{4 X} ) / 4
_{b x = (- P 1 X} + P 2 X + P 3 X -P 4 X) / 4
_{c x = (- P 1 X} -P 2 X + P 3 X + P 4 X) / 4
_{d x = (P 1 X -P} 2 X + P 3 X -P 4 X) / 4
_ay = ( _P1Y + _P2Y + _P3Y + _P4Y ) / 4
_{b y = (- P 1 Y} + P 2 Y + P 3 Y -P 4 Y) / 4
_{c y = (- P 1 Y} -P 2 Y + P 3 Y + P 4 Y) / 4
_{d y = (P 1 Y -P} 2 Y + P 3 Y -P 4 Y) / 4

Next, as shown in the lower part of FIG. 7, the third-type node copying unit 19 takes the position calculated by the coordinates of the corresponding nodes Q1 to Q4 and the normalized coordinates (r, s) in the new model M2. Copy node n20 '. The coordinates of the node n20 ′ as the copy destination are (Q _X , Q _Y ), and the coordinates of the plurality of nodes Q1 to Q4 around the node n20 ′ are (Q _{1 X} , Q _{1 Y} ), (Q _{2 X} , Q _{2 Y} ), (Q _{3 X} , Q _{3 Y} ), (Q _{4 X} , Q _{4 Y} ), the following formula is used. [N] is a shape function.

N ₁ = (1-r) (1-s) / 4
N ₂ = (1 + r) (1-s) / 4
N ₃ = (1 + r) (1 + s) / 4
N ₄ = (1−r) (1 + s) / 4

[Method for generating FEM analysis model]
A method of generating an FEM analysis model using the apparatus 1 will be described with reference to FIG.

First, in step S100, the new model generation unit 12 generates a new model having a member boundary line using the drawing data shown in FIG. 3A. In this new model, elements, nodes, and member information (member names, member material properties, etc.) are not defined.
In the next step S101, the member recognition unit 13 recognizes the closed region defined by the member boundary line in the new model M2 as one member.
In the next step S102, the member matching unit 14 associates the member of the existing FEM model M1 with the member of the new model M2. First to fourth member association processing is executed.
In the next step S103, the boundary line matching unit 15 associates the member boundary line of the existing FEM model M1 with the member boundary line of the new model M2. First to third boundary line association processing is executed. In the present embodiment, for the convenience of performing the fourth member association process, the member matching process in step S102 and the boundary line matching process in step S104 are performed simultaneously.
In the next step S104, the physical property data definition unit 16 defines the same material property data as the material property of the corresponding member in the existing FEM model M1 for the member in the new model M2 based on the association of the members. Note that the processing order of S102 to 104 can be changed as appropriate. For example, processing may be performed in the order of S102, S104, and S103, or processing may be performed in the order of S102, S103, and S104.
In the next step S105, the first-type node copying unit 17 copies the nodes (n1 to n8) on the member boundary line 30 in the existing FEM model M1 onto the corresponding member boundary line 30 ′ in the new model M2. .
In the next step S106, the second-type node copying unit 18 uses the nodes (n8 to n11) on the virtual straight line 40 connecting the nodes on the member boundary line in the existing FEM model M1 to the corresponding virtual models in the new model M2. Copy on line 40 '.
In the next step S107, the third type node copying unit 19 copies the node n20 that is not on either the member boundary line or the virtual line in the existing FEM model M1 to the new model M2.
In the next step S108, elements are constructed from the copied nodes, and boundary conditions (rim contact, internal pressure, ground contact candidate points, etc.) set in the existing FEM model M1 are defined in the new model M2 if possible. Then, the generation of the new model M2 ends.

  As described above, the FEM analysis model generation apparatus 1 according to the present embodiment generates a new model M2 having member boundary data based on the drawing data representing the structure to be newly modeled by the member boundary. New model generation unit 12 that recognizes, a member recognition unit 13 that recognizes a closed region surrounded by a member boundary in the new model M2 as one member, a predetermined reference line and a structure common to the new model M2 and the existing FEM model M1 Based on the arrangement order along the outline line of the object, based on the arrangement order along the outline line of the structure, the member matching unit 14 that associates the member of the new model M2 and the member of the existing FEM model M1, A boundary line matching unit 15 that associates the member boundary line of the new model M2 with the member boundary line of the existing FEM model M1, and the new model M2 A physical property data definition unit 16 that defines the same material physical property data as that of the corresponding member in the existing FEM model M1, and a node n7 on the member boundary line 30 in the existing FEM model M1 In copying on the corresponding member boundary line 30 ′ in FIG. 5, the node n7 ′ is copied at a position corresponding to the ratio of the length L1 of the member boundary line 30 to the length L2 from the end of the member boundary line 30 to the node n7. In copying the node n9 on the virtual straight line 40 connecting the first-type node copying unit 17 and the nodes on the member boundary line in the existing FEM model M1 onto the corresponding virtual straight line 40 ′ in the new model M2, The node n9 ′ is copied to a position corresponding to the ratio of the length L3 of the virtual straight line 40 to the length L4 from the end of the straight line 40 to the node n9. It includes a seed node duplicator 18.

  Further, the FEM analysis model generation method of the present embodiment generates a new model M2 having member boundary data based on drawing data representing a structure to be newly modeled by member boundary lines (S100). ), A step of recognizing a closed region surrounded by a member boundary line in the new model M2 as one member (S101), a predetermined reference line common to the new model M2 and the existing FEM model M1, and an outline line of the structure The member of the new model M2 is associated with the member of the new model M2 and the member of the existing FEM model M1 on the basis of the arrangement order along the alignment line, and the arrangement order along the predetermined reference line and the outline line of the structure. The step of associating the boundary line with the member boundary line of the existing FEM model M1 (S103), and the part in the new model M2 In contrast, the step (S104) of defining the same material property data as the material property of the corresponding member in the existing FEM model M1, and the node n7 on the member boundary line 30 in the existing FEM model M1 correspond to the new model M2. In copying on the member boundary line 30 ', the node n7' is copied to a position corresponding to the ratio of the length L1 of the member boundary line 30 to the length L2 from the end of the member boundary line 30 to the node n7 (S105). ) And the node n9 on the virtual straight line 40 connecting the nodes on the member boundary line in the existing FEM model M1 are copied onto the corresponding virtual straight line 40 ′ in the new model M2 from the end of the virtual straight line 40. copying the node n9 ′ to a position corresponding to the ratio of the length L3 of the virtual straight line 40 to the length L4 up to n9 Including S106 and), the.

  As described above, the drawing data representing the structure to be newly modeled by the member boundary line is used, and the member and the member boundary line of the new model M2 and the existing FEM model M1 are associated with each other and defined in the existing FEM model M1. Copy material properties, nodes and element data to match the member boundaries of the new model M2, so new models can be generated automatically or semi-automatically, greatly reducing model generation time and improving convenience And the development cost can be reduced.

  In the apparatus of the present embodiment, the member matching unit 14 and the boundary line matching unit 15 are the unprocessed member 22 and the member for the unprocessed member 22 that is not associated with the existing FEM model M1 among the members of the new model M2. If the adjacent members (23, 24, 25) are already associated with the boundary line, the unprocessed member 22 and the member of the existing FEM model M1 are associated with each other according to the adjacent positional relationship.

  In the method of the present embodiment, among the members of the new model M2, the unprocessed members 22 that are not associated with the members of the existing FEM model M1 are adjacent to the unprocessed members 22 with the member boundary line interposed therebetween (23 , 24, 25) is associated with the unprocessed member 22 and the member of the existing FEM model M1 according to the adjacent positional relationship (S102).

  As described above, since the members are associated according to the adjacent positional relationship, the structure of the structure is complicated, and the association cannot be sufficiently performed even if the association process is performed along the outer shape line and the predetermined reference line. Even if it exists, it becomes possible to associate sufficiently and accurately.

  In the apparatus of the present embodiment, in copying the node n20 that is not on either the member boundary line or the virtual line in the existing FEM model M1 to the new model M2, the nodes are based on the plurality of nodes P1 to P4 around the node n20. The normalized coordinate (r, s) representing the position of n20 is converted using a shape function, and is calculated from the coordinates of the corresponding nodes Q1 to Q4 and the normalized coordinate (r, s) in the new model M2. A third-type node copying unit 19 for copying the node n20 ′ to the coordinates is provided.

  In the method of the present embodiment, in copying the node n20 that is not on either the member boundary line or the virtual line in the existing FEM model M1 to the new model M2, the nodes are based on the plurality of nodes P1 to P4 around the node n20. The normalized coordinate (r, s) representing the position of n20 is converted using a shape function, and is calculated from the coordinates of the corresponding nodes Q1 to Q4 and the normalized coordinate (r, s) in the new model M2. Copying the node n20 ′ to the coordinates (S107).

  When the existing FEM model M1 is automatically generated using a tool, the node is arranged on either the member boundary line or the virtual straight line. In principle, the nodes of the existing FEM model M1 are arranged either on the member boundary line or on the virtual straight line. However, when a user manually adds or changes a node, there is a possibility that there is a node that is not arranged on either the member boundary line or the virtual straight line. Therefore, according to the present embodiment, it is possible to appropriately reflect a node that is not in either the member boundary line or the virtual straight line in the new model by manually adding or changing the existing FEM model. .

  In the present embodiment, the existing FEM model M1 and the newly modeled structure are tires, and the predetermined reference line is the tire equator line CL.

  In the FEM analysis model for a tire, a plurality of members are stacked and the structure becomes complicated. Therefore, the ability to generate a new model automatically or semi-automatically can significantly reduce the model generation time and is useful. Nevertheless, since the members constituting the tire skeleton concentrate on the tire equator line CL, it is possible to accurately realize the correspondence between the majority of the members constituting the tire and the member boundary lines, which is preferable because the processing speed can be improved.

  In the apparatus according to the present embodiment, the existing FEM model M1 and the new model M2 have data related to the tire size, and the member matching unit 14 and the boundary line matching unit 15 have a bead portion according to the tire size and a predetermined member shape. 2 and the member boundary line are associated with each other.

  In the method of the present embodiment, the existing FEM model M1 and the new model M2 have data relating to the tire size, and the correspondence between the members constituting the bead portion 2 and the member boundary lines according to the tire size and the predetermined member shape (S102, S103).

  Since the position of the bead portion 2 can be specified according to the tire size, and the shape of the bead core 20 and the like constituting the bead portion 2 is characteristic as compared with other members, the member and the member are obtained using tire-specific data. It is possible to improve the processing speed of the boundary line association, and to improve the throughput.

The computer program according to the present embodiment is a program that causes a computer to execute the steps constituting the FEM analysis model generation method.
By executing these programs, it is possible to obtain the operational effects of the above method. In other words, it can be said that the above method is used.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not only by the above description of the embodiments but also by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, the member matching unit 14 executes the first to fourth member association processes, but if the first to second member association processes are performed, the third to fourth processes can be omitted. . That is, an embodiment for executing the first to second member association processing, an embodiment for executing the first, second, and third member association processing, an embodiment for executing the first to fourth member association processing, There is an embodiment in which the first, second, and fourth member association processes are executed.

  The boundary line matching unit 15 executes the first to third boundary line association processes. However, if the first to second boundary line association processes are performed, the third process can be omitted. That is, there are embodiments that execute the first to second boundary line association processes and embodiments that execute the first to third boundary line association processes.

  In the above, an example in which the structure is a pneumatic tire has been described. However, the structure is not limited to a tire and can be applied to various structures.

  The structure employed in each of the above embodiments can be employed in any other embodiment. The specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 12 ... New model production | generation part 13 ... Member recognition part 14 ... Member matching part 15 ... Boundary line matching part 16 ... Physical property data definition part 17 ... 1st kind node copying part 18 ... 2nd kind node copying part 19 ... 3rd kind node Copy section 30, 30 '... member boundary line 40, 40' ... virtual straight line M1 ... existing FEM model M2 ... new model

Claims (11)

A new model generation unit that generates a new model having the data of the member boundary line based on the drawing data representing the structure to be newly modeled by the member boundary line;
A member recognition unit for recognizing a closed region surrounded by the member boundary line in the new model as one member;
A member matching unit that associates the member of the new model and the member of the existing FEM model based on the predetermined reference line common to the new model and the existing FEM model and the arrangement order along the outline of the structure;
A boundary matching unit that associates the member boundary of the new model with the member boundary of the existing FEM model based on the predetermined reference line and the arrangement order along the outline of the structure;
A physical property data defining unit for defining the same material property data as the material property of the corresponding member in the existing FEM model for the member in the new model;
In copying the node on the member boundary line in the existing FEM model onto the corresponding member boundary line in the new model, the ratio of the length of the member boundary line to the length from the end of the member boundary line to the node A first-type node copying unit that copies the node to a position according to
In copying the node on the virtual straight line connecting the nodes on the member boundary line in the existing FEM model onto the corresponding virtual straight line in the new model, the length relative to the length from the end of the virtual straight line to the node is A second-type node copying unit that copies the node to a position according to the ratio of the length of the virtual straight line;
An FEM analysis model generation apparatus comprising:   The member matching unit and the boundary line matching unit are adjacent to the unprocessed member that is not associated with the existing FEM model among the members of the new model with the member boundary line interposed therebetween. The FEM analysis model generation device according to claim 1, wherein when the member is already associated, the unprocessed member and the member of the existing FEM model are associated with each other according to the adjacent positional relationship.   In the existing FEM model, when a node that is not on either the member boundary line or the virtual line is copied to the new model, normalized coordinates that represent the position of the node with reference to a plurality of nodes around the node 3. A third-type node copying unit that converts a node into a coordinate calculated by a coordinate function and a coordinate calculated by the normalized coordinates in the new model. The apparatus for generating a model for FEM analysis described in 1. The existing FEM model and the newly modeled structure are tires,
The FEM analysis model generating apparatus according to claim 1, wherein the predetermined reference line is a tire equator line. The existing FEM model and the new model have data on tire size,
The FEM analysis model generation apparatus according to claim 4, wherein the member matching unit and the boundary line matching unit associate a member constituting the bead unit and a member boundary line according to the tire size and a predetermined member shape. . Generating a new model having the data of the member boundary line based on the drawing data representing the structure to be newly modeled by the member boundary line;
Recognizing a closed region surrounded by the member boundary in the new model as one member;
Associating a member of the new model with a member of the existing FEM model based on a predetermined reference line common to the new model and the existing FEM model and an arrangement order along the outline of the structure;
Associating a member boundary of the new model with a member boundary of the existing FEM model based on the predetermined reference line and the arrangement order along the outline of the structure;
Defining, for members in the new model, the same material property data as the material properties of the corresponding member in the existing FEM model;
In copying the node on the member boundary line in the existing FEM model onto the corresponding member boundary line in the new model, the ratio of the length of the member boundary line to the length from the end of the member boundary line to the node Copying the node to a position according to
In copying the node on the virtual straight line connecting the nodes on the member boundary line in the existing FEM model onto the corresponding virtual straight line in the new model, the length relative to the length from the end of the virtual straight line to the node is Copying the node to a position corresponding to a ratio of lengths of virtual lines;
A method for generating a model for FEM analysis , in which a computer is executed .   When an unprocessed member that is not associated with a member of the existing FEM model among the members of the new model is already associated with the unprocessed member and an adjacent member across the member boundary line The method for generating a model for FEM analysis according to claim 6, further comprising the step of associating the unprocessed member with the member of the existing FEM model according to the adjacent positional relationship.   In the existing FEM model, when a node that is not on either the member boundary line or the virtual line is copied to the new model, normalized coordinates that represent the position of the node with reference to a plurality of nodes around the node 8. The FEM analysis according to claim 6, further comprising: a step of: converting to a coordinate calculated by the position of a plurality of corresponding nodes and the normalized coordinates in the new model by using a shape function. Model generation method. The existing FEM model and the newly modeled structure are tires,
The method for generating a model for FEM analysis according to any one of claims 6 to 8, wherein the predetermined reference line is a tire equator line. The existing FEM model and the new model have data on tire size,
The method for generating a model for FEM analysis according to claim 9, comprising: associating a member that constitutes a bead portion and a member boundary line according to the tire size and a predetermined member shape.   A computer program for causing a computer to execute the FEM analysis model generation method according to claim 6.