JPH10312473A - Method for deleting cornor rounding part, cae system for realizing the same method and recording medium for recording program of the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time necessary for correction and thus the time for analysis by deleting part, for example, a small roundness part, which does not influence analysis and generating a simplified model in a method for correcting a detailed model and generating the simplified one. SOLUTION: In a mechanical CAE system for generating a model for analysis and executing an numerical analysis of construction or the like, a numerical value of a radius of roundness part, which does not affect the above result of analysis by way of a man-machine device 54, is given. Thus, a computer body 50 detects the roundness part in model above based on the programmed contents and by expanding the surface of the roundness part and cutting off crossing parts of each other, an exclusive simplified model for analysis is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a mechanical CAE (Co
The present invention relates to a method for deleting a rounded corner portion, which is suitable for use in model analysis by mputer Aided Engineering, a CAE system that realizes the method, and a recording medium on which the method is programmed and recorded.

[0002]

2. Description of the Related Art CAE is the concept of product design, which not only integrates the environment in which computers are used, but also integrates important parts of engineering design, experimental analysis, drafting, and manufacturing departments. is there. Using an integrated CAE system early in the product development phase not only significantly reduces development time and costs, but also enables more innovative and superior product development. .

FIG. 10 shows a typical flow of development and design of a mechanical product by CAE. The important point of this method is to generate a new product concept by computer, observe it, and evaluate the performance of the product at the system level through system simulation before making expensive prototypes. The layout and shape of the system can be easily defined and visualized using solid modeling techniques. The system dynamic characteristic analysis is based on the building block method (BBA). In BBA,
It deals with mathematical information on how to connect each part to each part in the system. By changing the mathematical representation of the required components and re-simulating the resulting new mathematical model, the relationship between system performance and component design conditions and their connection methods can be easily evaluated.

[0004] The system model and its parts can be represented by solid modeling software.
The mathematical information for the part can be obtained from the finite element method, from a data bank, or experimentally, if the part is present. The results of system analysis can be used to understand product issues under various operating conditions. For example, packaging, weight reduction, mechanical mechanism, vibration, sound, and other problems to be focused on in the development process of each mechanical component. Evaluating and solving these problems in a computer in the early stages of design not only focuses on manufacturing problems and costs in the early stages, but also reduces the need for trial production. Makes it possible.

[0005] A general analysis method in a mechanical CAE system will be described below with reference to an example of stress analysis.

(1) Create a model to be analyzed.

(2) The model is divided to create a finite element model.

(3) Set a constraint condition and a load condition.

(4) Perform analysis.

[0010]

In general, a model to be analyzed is not important for the result of the analysis. For example, a small rounded portion (hereinafter, referred to as an R portion) at a corner is simply model-created. . This model creation is shown in FIG.
As shown in (a), there are two methods: using a detailed model created by design and using it as a simplified model (b) for analysis, and creating a simplified model (b) dedicated to analysis from the beginning. Exists. Considering the applicability of the model,
The former is more efficient because the model can be used for both design and analysis.

However, in the above-described method of creating a simplified model by modifying the detailed model, it takes time to modify the simplified model, including parts that are not important for analysis. In addition, if an analysis model (finite element model) is created without modifying the design model, the number of finite elements increases, and the analysis time becomes extremely long, and in some cases, the analysis cannot be completed because the analysis does not converge. Sometimes.

The present invention has been made in view of the above circumstances. In a method of modifying a detailed model to create a simplified model, the method does not affect the analysis. For example, a simplified model is created by deleting a small R portion. To reduce the time required for the correction, and thereby to reduce the rounding time of the corner, thereby reducing the rounding time, a CAE system for realizing the method, and a recording medium on which the method is programmed and recorded The purpose is to provide.

[0013]

The first feature of the present invention is as follows.
In a mechanical CAE system that creates a model to be analyzed and performs a numerical analysis of the structure and the like, the radius of the corner rounded portion (R portion) that does not affect the result of the above analysis is given by a numerical value, so that R Search for a part and its R
The purpose of the present invention is to create a simple model dedicated to analysis by expanding the surface of the part and cutting off the intersection of the surfaces.

A second feature of the present invention is that, in a method of creating a three-dimensional (2) -dimensional analysis model and creating a simplified model for creating a finite element model, an R part having a value smaller than the radius R is used. To search, create a virtual sphere (circle) to search for the largest R value that needs to be deleted from the analysis model, specify a surface (line) to be searched, and make contact with the inner surface of the analysis model. The presence or absence of a contact is found by rolling (circle), and when there are two or more contacts, it is determined that the portion is an R portion that needs to be deleted, and the surface (line) is extended tangentially from the contact portion. Then, a portion after the plane (line) intersects is cut out and the corresponding R portion is deleted.

A third feature of the present invention is that a computer main body that creates a predetermined analysis model while interacting with an operator via a man-machine device and generates a simplified model for creating a finite element model, An input device for designating an R value having an arbitrary corner radius and a target corner portion for removing unnecessary corner portions from the inside thereof, and the computer main body comprises an R value designated via the input device. Create an imaginary sphere to search for the largest R value that needs to be deleted in order to search for an R part with a smaller value, and further specify the plane (line) to be searched via the input device, and The presence or absence of a contact is found by rolling a virtual sphere (circle) so that the inner and outer surfaces of the contact point are in contact with each other, and when there are two or more contacts, it is determined that the corner portion needs to be deleted, and the contact portion is determined. (Line) extends tangentially cut section after which the surface (line) is crossed, in the mechanical system CAE systems and deletes the partial rounding unnecessary corner.

A fourth feature of the present invention is each step for creating a predetermined analysis model and creating a simple model for creating a finite element model, which is not necessary through an input means. A step of specifying and accepting an R portion, a step of creating a virtual sphere (circle) having an input radius of R, and a surface (line) to be searched
And moving the virtual sphere (circle) so that the inner and outer faces (lines) are in contact with all of the specified faces (lines), confirm that there are two or more points of contact, ) To cut out the surface (line) of the recording medium is programmed and recorded.

Thus, the detailed model can be modified into a simple model for analysis by designating only the size of the unnecessary R portion, and the time required for analysis can be reduced.

[0018]

FIG. 1 is a block diagram showing a configuration example of a CAE system according to the present invention.

In the figure, workstation 2 terminals (1,
A relatively large-scale system is shown in which each device is connected to and centered on 2) and a router engine 1 terminal (3). The terminals 1, 2, 3 and the personal computers 4, 5 are connected by a LAN line 6 and can perform bidirectional file transfer, login, and the like.

Each terminal 1 including a personal computer
5 is equipped with a high-definition color graphics display device (CRT) and a large-capacity disk file device (MK) as standard equipment, and has a configuration in which a color electrostatic plotter (PRT) can be shared by switching and using. I have. Each of the terminals 1 to 5 including the personal computer is required to perform advanced theoretical calculations and high-precision graphic processing, so that a relatively high-performance type is required.

FIG. 2 is a diagram showing only software modules related to the present invention in the software data structure of the personal computer 5 shown in FIG. In the figure, 51 is UNI
A general-purpose OS such as X, Windows, etc., which forms the core of the system and performs multitasking and multiwindow processing.

Reference numeral 52 denotes each module configuration of CAE software serving as an application. The CAE software includes a system design module 521, a system analysis module 522, a three-dimensional part shape definition module 523, a finite element modeling module 524, a finite element analysis and optimization module 525, a graphic display module 526, an experiment / analysis module 527, and a two-dimensional module. The drafting module 528 is connected via the GUI interface 529. Each module 5 described above
21 to 528 commonly use the database 530.
531 is a CAD / CAM module and 532 is an experiment evaluation module. Each of these modules 521, 52
2, 523, 524, 525, 526, 527, 52
8 and 529 are resident in the disk file device 53, and are loaded into the main storage device 50 and used as needed.

Each of the modules described above processes the entire flow of the mechanical product design shown in FIG. 10. As described above, (1) the color shape representation by the solid model of the part and the assembly of the system, (2) ) Mechanism analysis including animation display, (3) color blur for finite element analysis, host processing, (4) finite element analysis, (5) system simulation, (6) 2D drafting,
(7) Perform an experimental analysis such as a fatigue analysis.

Reference numeral 54 denotes a color graphic display device having an input device such as a mouse and a keyboard.
Is a man-machine tool used for designing a layout while interacting with a designer via a basic input / output system (BIOS). The color graphic display device 54 has a built-in large-capacity bitmap memory and can display a high-resolution high-definition image. Reference numeral 55 denotes a LAN card, which can communicate with another system via the LAN via the basic input / output system of the OS. 56 is C
The PU is a PU that realizes a function described later by sequentially reading and executing a program stored in the main storage device 50, and is a control center of the system of the present invention in CAE.

FIG. 3 is a flow chart showing the flow of processing by software for the part of the finite element modeling shown in FIG. 2 that corrects a detailed model to a simplified model.

FIGS. 4 to 9 are views cited for explaining the operation of the embodiment of the present invention. The analysis model, the virtual sphere (circle), the expansion of the plane (line), the created simplified model, the simplified model The finite element model in the model and the finite element model in the detailed model are shown.

The operation of the embodiment of the present invention shown in FIGS. 1 and 2 will be described below in detail with reference to FIGS.

First, the operator uses the keyboard 54 to
In order to correct a corner having an R part smaller than a certain value of R, the maximum R value to be corrected is input. In the embodiment of the present invention, the distance is set to 2 mm. The radius R may be designated by using a mouse instead of a keyboard, and may be selected from numerical values displayed on the screen in advance. CPU 56 receiving this
Creates a virtual sphere in order to find an R part having a value smaller than the input R value. In the embodiment of the present invention, a two-dimensional display is illustrated to facilitate understanding, so that it is a virtual circle.

Next, a target plane (line) is designated via the mouse. The search target of the unnecessary R portion is left to the input of the operator, and all or a part can be arbitrarily designated. Here, it is assumed that all are selected. This allows the CPU
As shown in FIG. 5, reference numeral 56 rolls a virtual sphere (circle) so as to contact the inner and outer surfaces of the model, and checks the number of contact points. The presence / absence of a contact point uses a well-known mathematical method based on geometric calculation. Here, if there are two or more contacts, it is determined that the shape of the portion is an unnecessary R portion. Then, as shown in FIG. 6, the surface (line) is extended in the tangential direction from the contact portion. Then, as shown in FIG. 7, the portion after the intersection of the planes (lines) is an unnecessary part, so that the existing planes (lines) are cut out, and a simplified model is created. This cutting is also performed by an existing mathematical method.

FIGS. 7 and 8 show a finite element model (automatic mesh generation, 80 elements) in the simplified model, respectively.
) And a finite element model (automatic mesh creation, 315 elements) in the detailed model. To search for unnecessary R parts,
A virtual sphere (circle) is created based on the input unnecessary R part, and the number of contacts is rolled on a surface (line) to be searched using a mathematical method such as a known algebraic geometry. Ask. After the unnecessary portion search, a known mathematical method or the function of the existing system is used to expand the surface (line) in the tangential direction at the point beyond the contact point, and cut off the intersection of the surfaces (lines). Is used. By using a known mathematical method, it is easy and efficient to construct a system. The model created here is a model for creating the finite element shown in FIG.

[0031]

As described above, according to the present invention, a predetermined analysis model is created, and a numerical analysis such as a structural analysis is performed.
It provides a method for creating a simplified model with improved analysis efficiency by searching for unnecessary R parts from the model and extending the plane (line), using the functions and mathematical methods of known systems. Therefore, system construction is easy. In addition, the following effects can be obtained.

(1) The detailed model can be automatically corrected to a simple model simply by specifying the size of the unnecessary R portion.

(2) Since a target surface can be specified, a fixed R portion can be deleted for all surfaces (lines) at once, and R portions having different sizes can be deleted in a plurality of portions. You can also.

(3) Since a finite element model that does not depend on the unnecessary R portion can be created, the number of elements can be reduced, and the analysis time can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a software structure used in the present invention.

FIG. 3 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 4 is a diagram showing an example of a screen display cited to show the operation of the embodiment of the present invention.

FIG. 5 is a view showing an example of a screen display cited to show the operation of the embodiment of the present invention.

FIG. 6 is a view showing an example of a screen display cited to show the operation of the embodiment of the present invention.

FIG. 7 is a view showing an example of a screen display cited to show the operation of the embodiment of the present invention.

FIG. 8 is a view showing an example of a screen display cited to show the operation of the embodiment of the present invention.

FIG. 9 is a view showing an example of a screen display cited to show the operation of the embodiment of the present invention.

FIG. 10 is a diagram showing a typical flow of a conventional mechanical product development and design by CAE.

FIG. 11 is a diagram showing a conventional model creation.

[Explanation of symbols]

1, 2, ... workstation, 3 ... router engine,
4, 5 personal computer, 6 LAN line, 5
0: Computer main body, 51: OS, 52: CAE software module, 521: System design module, 53: Disk device, 54: Man-machine device, 55
... LAN card, 56 ... CPU, 522 ... System analysis module, 523 ... 3D part shape definition module,
524: Finite element modeling module, 525: Finite element analysis and optimization module, 526: Graphic display module, 527: Experiment / analysis module, 52
8 ... two-dimensional drafting module, 529 ... GUI
Interface, 530 ... Database, 531 ... CA
D / CAM module, 532 ... Experiment evaluation module.

Claims (7)

[Claims] 1. In a mechanical CAE system for creating a model to be analyzed and performing a numerical analysis of a structure or the like, a corresponding corner rounding is given by giving a numerical value a radius of a corner rounding portion which does not affect the result of the analysis. A simple model dedicated to analysis is created by searching for parts, expanding the faces or lines at the corners in the tangential direction, and cutting out the faces or lines beyond the intersection of the faces or lines. How to remove rounded corners. 2. Designation of a surface or a line to be searched is
2. The method according to claim 1, wherein the corner is at least a part of a corner constituting the analysis model. 3. A method for creating a three-dimensional analysis model and creating a simplified model for creating a finite element model, wherein a deletion from the analysis model is performed to search for a corner rounded portion having a value smaller than the radius R. Create a virtual sphere to search for the required maximum R value, specify the surface to be searched, and roll the virtual sphere so that it touches the inner surface of the analysis model to find the presence or absence of a contact, and find two or more contacts When there is, it is determined that the part is a corner rounding part that needs to be deleted, the surface is extended in the tangential direction from the contact portion, the part after the surface intersects is cut out, and the corresponding corner rounding part is deleted. How to remove the rounded corners that are the feature. 4. In a method of creating a two-dimensional analysis model and generating a simplified model for creating a finite element model, in order to search for a corner rounded portion having a value smaller than the radius R, deletion is performed from the analysis model. Create a virtual circle to search for the required maximum R value, specify the line to be searched, and roll the virtual circle so as to touch the inner surface of the analysis model to find the presence or absence of a contact, and find two or more contacts When there is, it is determined that the part is a corner rounding part that needs to be deleted, the line is extended in the tangential direction from the contact point, the part after the line intersects is cut, and the corresponding corner rounding part is deleted. How to remove the rounded corners that are the feature. 5. The presence or absence of a contact is found by designating a surface to be searched and rolling a virtual sphere (circle) so as to touch the inner surface of the detailed model. Is determined to be an R part that needs to be deleted, and the operation of expanding the surface (line) from the contact point in the tangential direction and cutting off the part after the intersection of the surface (line) is specified. The method according to claim 3 or 4, wherein the same operation is repeated for the outer surface (line) until the completed surface (line) is completed. 6. A computer main body for creating a predetermined analysis model while interacting with an operator via a man-machine device and generating a simplified model for creating a finite element model, and an unnecessary corner portion from the analysis model. An input device for designating an R value having an arbitrary corner radius and a corner portion to be deleted, the computer main unit comprising: an R portion having a smaller value than the R value specified via the input device; Create a virtual sphere that searches for the maximum R value that needs to be deleted in order to search for, and specify the surface (line) to be searched via the input device, and touch the inner and outer surfaces of the analysis model. Rolling the virtual sphere (circle) detects the presence or absence of a contact, and when there are two or more contacts, determines that the corner portion needs to be deleted, and moves the surface (line) from the contact portion in the tangential direction. Expanded to A mechanical CAE system characterized by cutting off a portion after a plane (line) intersects and removing an unnecessary corner rounding portion. 7. A simple model generation step of generating a predetermined analysis model and generating a simple model for generating a finite element model, wherein an unnecessary R portion is specified via input means. Accepting, a step of creating a virtual sphere (circle) having an input radius of R, a step of specifying a surface (line) to be searched,
Move the virtual sphere (circle) so that the inner and outer faces (lines) are in contact with all the specified faces (lines), confirm that there are two or more points of contact, expand the faces (lines), Recording a surface (line) is programmed and recorded.