JP2010067159A - Device, method and program for supporting design work of object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of easily generating a mesh model after a design change even if repeating the design change. <P>SOLUTION: A design support device is provided with a means for storing shape data that describe a design shape of an object, a mesh model of the shape data, and link data. The link data describe nodes in the mesh model located on each vertex, an edge line or a plane of the vertex, an edge line or a plane of the design shape described by the shape data. The design support device is also provided with a means for changing the design shape described by the shape data, and a morphing means for executing a morphing operation of the stored mesh model in accordance with a change in the design shape. The morphing means executes a morphing operation so that each node of the mesh model described in the link data is located on the same vertex, the edge line or the plane even in the design shape after the design change with reference to the link data. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for supporting object design work. In particular, the present invention relates to a technology for supporting an object design work using a finite element method.

  Patent Document 1 discloses a technique for supporting an object design work using a finite element method. In this technology, the shape of the object after the design change is divided into meshes using the mesh model obtained by dividing the shape of the object before the design change and the deformed surface data describing the deformed portion of the shape after the object design change. Create a mesh model. More specifically, the mesh model before the design change of the object is overlaid with the deformation surface described by the deformation surface data, and the mesh model surface nodes located near the deformation surface are positioned on the deformation surface. Each node is moved (so-called morphing operation). According to this technique, when an object design is changed, a mesh model after the design change can be efficiently created using the mesh model before the design change. Since there is no need to create a new mesh model after the design change, the mesh model after the design change can be created in a short time, and the design work of the object using the finite element method can be advanced efficiently. .

JP 2007-334726 A

In the technique described in Patent Literature 1, in order to create a mesh model after a design change, deformed surface data describing a changed portion where the design change has been made is required. Therefore, when the design change is repeatedly performed, for example, when a parameter study is performed on a specific design dimension, it is necessary to separately generate deformation surface data every time the design change is performed. It is difficult to automate the creation of deformed surface data, and if it is necessary to create deformed surface data each time a design change is made, the resulting workload becomes relatively large.
The present invention solves the above problems. The present invention provides a technique capable of easily creating a mesh model after a design change even when the design change is repeatedly performed.

  The present invention is embodied in an apparatus that supports object design work. The apparatus includes means for storing shape data describing a design shape of an object, means for storing a mesh model of the design shape described by the shape data, each vertex of the design shape described by the shape data, each edge, and Means for storing link data describing the vertexes, ridge lines, or nodes in the mesh model located on the surface in association with each surface; means for changing the design shape described by the shape data; The mesh model and link data that has been changed and the shape data after the change are used, and each node of the mesh model described in the link data corresponds to the vertex, edge, or surface corresponding to the design shape described by the shape data after the change. Morphing means for performing a morphing operation on the mesh model is provided.

In the apparatus described above, the correspondence between each vertex, each ridgeline, and each surface of the design shape described by the shape data, and each node in the mesh model located on each vertex, each ridgeline, and each surface, It can be given in advance by link data. As a result, when the design shape described by the shape data is changed, each node of the mesh model described by the link data is the same vertex, edge, or even in the design shape described by the changed shape data. A morphing operation can be performed on the mesh model so as to lie on the surface. Thereby, the mesh model after the design change can be created in a short time without greatly changing the quality.
Before and after changing the design shape, the correspondence between each vertex, each ridgeline, and each surface of the design shape and each node in the mesh model located on each vertex, each ridgeline, and each surface is maintained as it is. Is done. Accordingly, since the link data prepared first is effective after the design change, it is not necessary to prepare the link data every time the design change is performed.
According to this apparatus, even when the design change is repeated, the mesh model after the design change can be easily created.

The above-described design support apparatus preferably further includes analysis means for executing analysis processing by the finite element method using the mesh model after the morphing operation by the morphing means.
This makes it possible to perform a series of design changes in shape data, a morphing operation of the mesh model accompanying the design change, and an analysis process using the mesh model after the morphing operation.

The technique of the present invention can also be embodied in a method for supporting object design work. In this method, a computer stores shape data describing the design shape of an object, a process of storing a mesh model of the design shape described by the shape data, and each vertex and edge of the design shape described by the shape data. A process for storing link data described in association with nodes in the mesh model located on the vertex, ridge line, or face for each and each face, and a process for changing the design shape described by the shape data; Using the stored mesh model and link data and the changed shape data, each node of the mesh model described in the link data corresponds to the vertex, ridge line, and the corresponding design shape described by the changed shape data. Or the morphing process which performs morphing operation with respect to a mesh model is performed so that it may be located on a surface.
According to this method, the mesh model after the design change can be easily created even when the design change is repeated.

The technique of the present invention can also be embodied in a program for executing the above-described method. That is, the program stores, in a computer, processing for storing shape data describing the design shape of an object, processing for storing a mesh model of the design shape described by the shape data, and for each vertex of the design shape described by the shape data. For each ridgeline and each surface, a process for storing link data described in association with the vertexes, ridgelines, or nodes in the mesh model located on the surface, and a process for changing the design shape described by the shape data Then, using the stored mesh model and link data and the changed shape data, each node of the mesh model described in the link data corresponds to the vertex corresponding to the design shape described by the changed shape data, A morphing process is executed to execute a morphing operation on the mesh model so as to be positioned on the ridgeline or the surface.
By using this program, the mesh model after the design change can be easily created even when the design change is repeated.

  According to the present invention, it is possible to efficiently advance design work for machine parts and the like, and it is possible to develop a highly reliable product in a relatively short time.

First, preferred embodiments for carrying out the present invention will be listed.
(Embodiment 1) The design support apparatus preferably includes shape data processing means (CAD system) for creating and editing shape data (CAD data).
(Mode 2) The design support apparatus preferably includes a mesh creation system for creating a mesh model from shape data.
(Mode 3) The design support apparatus preferably includes a link data creation system that creates link data from shape data and mesh data describing a mesh model.

(Mode 4) In the morphing operation by the morphing means, as a pre-process, for each node of the mesh model described in the link data,
A process of specifying the position in the design shape after the change of the vertex, the ridgeline, or the surface associated with the link data from the changed shape data;
It is preferable to execute a process of setting the position in the design shape after changing the specified vertex, ridge line, or face as the movement target position after the morphing operation.
By setting the moving target position in advance, the mesh model nodes described in the link data are then described by the modified shape data using a general mesh morphing method. The morphing operation can be performed on the mesh model so that the shape is located on the corresponding vertex, ridgeline, or surface.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a design support apparatus 10 according to the present embodiment. The design support apparatus 10 is a computer used by a designer who designs the shape of a machine part. By using the design support apparatus 10, the designer can obtain the optimum design shape of the machine part by repeating design changes while confirming the mechanical characteristics of the designed machine part.
The design support apparatus 10 is configured using a general-purpose computer, and various functional parts shown in FIG. 1 are configured by computer hardware and software (computer program). The design support apparatus 10 can be configured by a single computer or can be configured by a plurality of computers.

  As illustrated in FIG. 1, the design support apparatus 10 includes a data storage unit 20 for storing CAD data 22, mesh data 24, and link data 26. The design support apparatus 10 can input and store CAD data 22, mesh data 24, and link data 26 from the outside. As will be described in detail later, the design support apparatus 10 can also create the CAD data 22, the mesh data 24, and the link data 26 by itself based on instructions from the designer.

  The CAD data 22 is data describing the design shape of the machine part. FIG. 2 shows an example of the design shape 110 described by the CAD data 22. Here, the design shape 110 is a cube having a width W1, a height H1, and a depth D1. In the CAD data 22, each vertex P (= P1, P2, P3,...), Each ridge line E (= E1, E2, E3,...), And each surface F (= F1, F2) of the design shape 110. , F3,...) Is attached with identification information for individually identifying each. The CAD data 22 can be created by a general CAD device.

The mesh data 24 is data describing a mesh model obtained by dividing the design shape 110 described by the CAD data 22 into meshes. FIG. 3 shows an example of the mesh model 112 described by the mesh data 24. As shown in FIG. 3, in the mesh model 112, a large number of finite elements 114 are connected by a large number of nodes N (= N111, N112, N113,...). In the mesh data 24, identification information for individually identifying each node N (= N111, N112, N113,...) Is attached. The mesh data 24 can be created by a general mesh creation device.
Here, the mesh model 112 shown in FIG. 3 is illustrated with a simplified configuration for convenience of explanation. That is, the actual mesh model 112 is composed of a larger number of minute finite elements 114. Further, the shape of the finite element 114 is not limited to the hexahedral element shown in FIG. 3, and may be other forms such as a tetrahedral element.

The link data 26 is data describing a correspondence relationship between the vertex P, the ridge line E, and the surface F of the design shape 110 described by the CAD data 22 and the node N of the mesh model 112 described by the mesh data 24. FIG. 4 shows an example of the data structure of the link data 26. As shown in FIG. 4, the link data 26 is located on the vertex P, the ridge line E, or the surface F for each vertex P, each ridge line E, and each surface F of the design shape 110 described by the CAD data 22. A node N of the mesh model 112 is described.
For example, as is apparent from FIGS. 2 and 3, the node N <b> 111 of the mesh model 112 is located on the vertex P <b> 1 of the design shape 110. Therefore, as shown in FIG. 4, in the link data 26, the identification information of the vertex P1 and the identification information of the node N111 are described in association with each other. Similarly, nodes N122, N123, N132, and N133 of the mesh model 112 are located on the surface F1 of the design shape 110. Therefore, in the link data 26, the identification information of the face F1 and the identification information of the nodes 122, N123, N132, and N133 are described in association with each other.

As shown in FIG. 1, the design support apparatus 10 includes a CAD system 32, a mesh creation system 34, a link data creation system 36, an FEM analysis system 38, and a morphing system 40.
The CAD system 32 is a functional part that creates the CAD data 22 in accordance with a designer's instruction (operation). The CAD system 32 only needs to have the same function as a general CAD device. The CAD system 32 allows the designer to newly create CAD data 22 and store the created CAD data 22 in the data storage unit 20. Further, the designer reads the existing CAD data 22 from the data storage unit 20, changes the design shape 110 described by the CAD data 22, and stores the new CAD data 22 after the change in the data storage unit 20. Can do.

  The mesh creation system 34 is a functional part that inputs the CAD data 22 from the data storage unit 20 and creates the mesh model 112 of the design shape 110 described by the CAD data 22. The mesh creation system 34 only needs to have the same function as a general mesh creation device. The mesh creation system 34 allows the designer to create a mesh model 112 of the design shape 110 designed by the CAD system 32 and store the mesh data 24 describing the mesh model 112 in the data storage unit 20.

  The link data creation system 36 is a functional part that creates the link data 26 described above using the CAD data 22 stored in the data storage unit 20 and the mesh data 24 corresponding thereto. The processing procedure in which the link data creation system 36 creates the link data 26 is not particularly limited. The link data creation system 36 of this embodiment sequentially extracts each vertex P, each ridge line E, and each surface F from the CAD data 22, and the position (range) of the extracted vertex P, ridge line E, or surface F. The link data 26 is created by specifying the node N that coincides with the mesh data 24. The link data creation system 36 does not need to automatically create the link data 26, and may create the link data 26 according to an instruction (operation) from the designer.

  The FEM analysis system 38 is a functional part that executes analysis processing by the finite element method using the mesh data 24 stored in the data storage unit 20. The FEM analysis system 38 only needs to have the same function as a general FEM analysis. Thereby, the designer can grasp the mechanical characteristics of the design shape 110 designed by the CAD system 32.

  The morphing system 40 is a functional part that executes a morphing operation on the mesh data 24 stored in the data storage unit 20. The morphing operation uses the mesh model 112 described by the existing mesh data 24 and changes the position of the node N or the shape of the finite element 114 to directly (newly) a mesh model having a new design shape. (Without the need for CAD data describing a simple design shape). However, as will be described in detail later, the morphing system 40 according to the present embodiment has the existing design shape 110 when the design change is performed and the CAD data 22 describing the new design shape is created. A morphing operation is performed on the mesh model 112. At this time, the morphing system 40 refers to the link data 26 so that the nodes N located at any one of the vertices P, the ridge lines E, and the surfaces F of the design shape 110 are changed after the design change. The morphing operation is executed so that the design shape is located on the same vertex P, ridge line E, or plane F.

  As shown in FIG. 1, the design support apparatus 10 includes an input device 52, a display device 54, and a storage medium drive 56. The input device 52 is a mouse or a keyboard, for example, and accepts instructions from the designer. The display device 54 is a liquid crystal display, for example, and visually displays various data and analysis results. The storage medium drive 56 is a DVD drive, for example, and can transfer various data (CAD data 22, mesh data 24, link data 26, etc.) via a storage medium such as a DVD.

  FIG. 5 is a flowchart showing the flow of design work using the design support apparatus 10. The design work using the design support apparatus 10 will be described with a specific example along the flowchart shown in FIG. In the following description, as a specific example, the design shape 110 shown in FIG. 2 is used as a reference (initial shape), and an operation for searching for an optimal design shape is performed by repeating design changes on the reference design shape 110. Will be explained.

First, in step S10, the designer uses the CAD system 32 to design a design shape 110 as a reference, and creates CAD data 22 describing it (see FIG. 2). Hereinafter, the reference design shape 110 may be specifically referred to as a reference design shape 110, and the CAD data 22 describing the reference design shape 110 may be particularly referred to as reference CAD data 22. The created reference CAD data 22 is stored in the data storage unit 20. The reference CAD data 22 does not necessarily have to be newly created at this stage, and the existing CAD data 22 may be used.
In step S12, the mesh creation system 34 reads the reference CAD data 22 from the data storage unit 20, and creates the mesh model 112 of the reference design shape 110 (see FIG. 3). Hereinafter, the mesh model 112 of the reference design shape 110 may be specifically referred to as a reference mesh model 112, and the mesh data 24 describing the reference mesh model 112 may be particularly referred to as reference mesh data 24. The data storage unit 20 stores reference mesh data 24 describing the created reference mesh model 112.

In step S14, the link data creation system 36 reads the reference CAD data 22 and the reference mesh data 24 from the data storage unit 20, and creates link data 26 relating to both (see FIG. 4).
In step S <b> 16, the designer sets various analysis conditions for analysis processing by the FEM analysis system 38. Specifically, boundary conditions (fixed position, load load, overload position), material properties (Young's modulus, etc.), etc. are set. These settings are performed using the preprocessor of the FEM analysis system 38, and an input file describing various set analysis conditions is created.
In step S18, the FEM analysis system 38 executes analysis processing by the finite element method using the reference mesh data 24 read from the data storage unit 20 and the input file created in step S16, and outputs the analysis result. . The analysis result by the FEM analysis system 38 is displayed on the display device 54, for example, and confirmed by the designer.

  In step S <b> 20, the reference design shape 110 described in the reference CAD data 22 satisfies the required mechanical characteristics (optimum solution) based on the analysis result by the FEM analysis system 38. It is determined whether or not. If the reference design shape 110 is the optimal solution (YES), the operation is terminated assuming that the desired design shape is obtained. If the reference design shape 110 is not the optimal solution (NO), the process proceeds to step S22, and the design change is performed on the reference design shape 110. Here, the determination in step S20 may be automatically performed by the design support apparatus 10 by instructing the design support apparatus 10 in advance with necessary mechanical characteristics.

In step S22, the designer uses the CAD system 32 to change the reference design shape 110 described by the reference CAD data 22, and for example, new CAD data describing a new design shape 120 as shown in FIG. 22 is created. Hereinafter, the new design shape 120 after the design change may be particularly referred to as a new design shape 120, and the new CAD data 22 describing the new design shape 120 may be particularly referred to as new CAD data 22. In the new design shape 120 shown in FIG. 6, the width is changed from W1 to W2, the height is changed from H1 to H2, and the depth is changed from D1 to D2. This design change is an example for clarifying the description.
Here, the determination process of the previous step S20 and the design change process of this step S22 can be automated by incorporating general optimization software. In this case, a design dimension (one or a plurality of widths, heights, and depths) for which a design change is to be made and a change width thereof are set in advance, and the CAD system 32 configures a system that automatically creates new CAD data 22. It is good to keep.

  In step S24, in response to the design change in step S22, the morphing system 40 performs a morphing operation on the reference mesh model 112. Thereby, as shown in FIG. 7, a mesh model 122 obtained by dividing the new design shape 120 into meshes is created. Hereinafter, the mesh model 122 of the new design shape 120 may be particularly referred to as a new mesh model 122, and the new mesh data 24 describing the new mesh model 122 may be particularly referred to as new mesh data 24. The data storage unit 20 stores new mesh data 24 describing the created new mesh model 122.

  In the morphing operation in step S24 described above, new CAD data 22, reference mesh data 24, and link data 26 stored in the data storage unit 20 are used. The morphing system 40 uses, for each node N described in the link data 26, the position (range) after the design change of the vertex P, the edge E, or the surface F associated with the node N as new CAD data. 22 is specified. The morphing system 40 sets each position (range) read from the new CAD data 22 for each node N as a target position for moving each node N, and then executes a morphing operation on the reference mesh model 112. (Node N movement processing and finite element 124 deformation processing). The morphing operation after setting the target position of each node N is not particularly limited, and can be performed using various commercially available morphing software. However, in the design support apparatus 10 of the present embodiment, the position is set on each vertex P, each ridge line E, and each surface F at the stage of the reference design shape 110 by setting the target position using the link data 26. Even after the design change to the new design shape 120, each node N that has been arranged is arranged again on each corresponding vertex P, each ridge line E, and each surface F. As a result, before and after the design change, the same node N of the mesh models 112 and 122 is located at each vertex P, each ridge line E, and each surface of the design shapes 110 and 120 (FIGS. 2 and 3). 6 and 7). Therefore, even after the design change, the link data 26 is the data in which the correspondence between the new CAD data 22 and the new mesh data 24 is correctly described.

In step S26, the analysis conditions set in step S16 are corrected based on the new mesh data 24 created in step S24. That is, as the node N moves, the boundary conditions (fixed position, overload position, etc.) are changed and new input data is created.
After step S26, the process returns to step S18, and the FEM analysis system 38 re-executes the analysis process using the new mesh data 24 and the new input data. Thereafter, the process from step S18 to S26 is repeated, and the design change is repeated to search for the optimum design shape. At this time, the new CAD data 22 and the new mesh data 24 created in the previous cycle are used as the reference CAD data 22 and the reference mesh data 24 in the next cycle. Since the link data 26 is always valid even when the design change is repeated, it is not necessary to recreate the link data 26.

  As described above, in the design support apparatus 10 of the present embodiment, when a design change is performed on the reference design shape 110, a new morphing operation is performed on the reference design shape 110 from the mesh model 112 of the reference design shape 110. A mesh model 112 of the design shape 120 is created. Thereby, the mesh model 112 after the design change can be created in a short time without greatly changing its quality.

  In particular, in the design support apparatus 10 of the present embodiment, each vertex P, each ridge line E, and each node N located on each surface F of the reference design shape 110 is also in the new design shape 120 after the design change. A morphing operation is performed on the reference mesh model 112 so as to be positioned on the same vertex P, each ridge line E, and each surface F. Therefore, before and after the design change, the configuration of the mesh models 112 and 122 does not change greatly, and the quality is particularly maintained. In order to execute such a morphing operation, the design support apparatus 10 needs the link data 26. However, it is sufficient to create the link data 26 only at the stage of the reference design shape 110, and every time the design is changed. There is no need to recreate the link data 26.

In general, when the morphing operation is performed on the reference mesh model 112 using the mesh morphing software, it is not necessary to return to the reference CAD data 22 to make a design change, and directly to the reference mesh model 112. It is possible to make design changes. However, when a design change is made directly on the reference mesh model 112, new CAD data 22 describing the new design shape 120 from the new mesh model 122 at that time is obtained when a good analysis result is obtained. Work to create is required. In creating the new CAD data 22, if the new design shape 120 is created faithfully to the outer shape of the new mesh model 122, a design dimension that is inconvenient in manufacturing (for example, machining accuracy such as 10.1251 mm). May be a small dimension that cannot be guaranteed). In this case, the designer will modify the design dimensions based on experience (for example, 10.251 mm is corrected to 10.0 mm). Such artificial adjustment of the design dimensions has a considerable influence on the mechanical characteristics of the new design shape 120, and the new design shape 120 after adjustment does not satisfy the required mechanical characteristics. Can also occur. Further, when changing design variables at a plurality of locations that interfere with each other, the complicated three-dimensional shape obtained by the morphing operation is replaced with a designally meaningful dimension on the CAD data 22. Can be very difficult.
On the other hand, in the design support apparatus 10 of the present embodiment, the design change is made in the CAD data 22, and the creation and analysis processing of the mesh data 24 is performed based on the design change. Therefore, when a good analysis result is obtained. The CAD data 22 describing the new design shape 120 already exists. Therefore, the above-described problems do not occur.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The figure which shows the structure of the design assistance apparatus of an Example. The figure which shows an example of the design shape which CAD data describes. The figure which shows an example of the mesh model which mesh data describes. The figure which shows the data structure of link data. The flowchart which shows the flow of the design operation | work using a design support apparatus. The figure which shows an example of the new design shape which new CAD data describes. The figure which shows an example of the new mesh model which new mesh data describes.

Explanation of symbols

10: Design support device 20: Data storage unit 22: CAD data 24: Mesh data 26: Link data 32: CAD system 34: Mesh creation system 36: Link data creation system 38: FEM analysis system 40: Morphing system 52: Input device 54: Display device 56: Storage medium drive 110: Design shape (reference design shape)
112: Mesh model (reference mesh model)
120: Design shape (new design shape)
122: Mesh model (new mesh model)

Claims (4)

An apparatus for supporting object design work,
Means for storing shape data describing the design shape of the object;
Means for storing a mesh model of a design shape described by shape data;
Means for storing link data describing the vertexes, ridgelines, or nodes in the mesh model located on the surface in association with each vertex, ridgeline, and surface of the design shape described by the shape data;
Means for changing the design shape described by the shape data;
Using the stored mesh model and link data and the changed shape data, each node of the mesh model described in the link data corresponds to the vertex, ridge line, and the corresponding design shape described by the changed shape data. Or a morphing means for performing a morphing operation on the mesh model so as to be located on the surface;
A device comprising:   The apparatus according to claim 1, further comprising an analysis unit that executes an analysis process by a finite element method using a mesh model after the morphing operation by the morphing unit. A method for supporting the design work of an object,
Processing to store shape data describing the design shape of the object;
A process of storing a mesh model of a design shape described by shape data;
A process of storing link data describing the vertexes, ridge lines, or nodes in the mesh model located on the surface in association with each vertex, ridge line, and surface of the design shape described by the shape data;
A process of changing the design shape described by the shape data;
Using the stored mesh model and link data and the changed shape data, each node of the mesh model described in the link data corresponds to the vertex, ridge line, and the corresponding design shape described by the changed shape data. Or a morphing process for performing a morphing operation on the mesh model so as to be located on the surface;
How to run. A program for supporting object design work,
Processing to store shape data describing the design shape of the object;
A process of storing a mesh model of a design shape described by shape data;
A process of storing link data describing the vertexes, ridge lines, or nodes in the mesh model located on the surface in association with each vertex, ridge line, and surface of the design shape described by the shape data;
A process of changing the design shape described by the shape data;
Using the stored mesh model and link data and the changed shape data, each node of the mesh model described in the link data corresponds to the vertex, ridge line, and the corresponding design shape described by the changed shape data. Or a morphing process for performing a morphing operation on the mesh model so as to be located on the surface;
A program that executes

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