JP2000331194A - Method for simplifying shape model - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the number of meshes and also to shorten the numerical analysis time by providing a trace means which can apply the shape simplification process data obtained before the shape change to a shape model obtained after the shape change when the shape of the shape model is changed. SOLUTION: A simplifying feature retrieval part 106 reads the shape simplifying process data registered in a shape simplifying process data base 105 and retrieves the feature to be simplified. A simplifying feature data base 115 holds the relevant feature as a simplifying feature in response to the retrieval result of the part 106. A simple model production part 107 registers the simple model data 114 by deleting the feature registered in the data base 115 from a shape model. A numerical analysis processing part 109 performs the numerical analysis according to the mesh data 113. An analysis error register part 110 compares the analysis results obtained before and after the shape model is simplified with each other and registers the difference of both analysis results into the data base 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CAE system that optimizes and rationalizes design work by numerical simulation using a computer, and in particular, simplifies a shape model by removing features in the shape model to be analyzed. Related to a simplified shape model simplification technique.

[0002]

2. Description of the Related Art Conventional techniques for easily simplifying a portion of a shape model to be analyzed that does not affect the analysis accuracy include the following method.

The first is to search for a corresponding fillet portion by giving a numerical value the radius of the fillet portion that does not affect the analysis accuracy in the shape model, expand the surface of the fillet portion in the tangential direction, and intersect each other. This is a method of creating a simplified model by cutting out the surface beyond the part. This is described in JP-A-10-312473.

[0004] Second, when the user specifies the type of simplification and the shape element to be simplified, the state is parallel to the shape element and the connection state is concave, convex, or smooth. In this method, a simplified model is created by extracting shape elements characterized by the above from shape data and deleting or combining target shape elements. This is described in JP-A-6-259505.

[0005]

In the above two methods, it is necessary to specify a portion to be simplified each time the shape is changed, and the number of steps for creating a simplified model increases. further,
In both methods, the shape is simplified by the geometric operation, so that much time is required for processing, or a simplified model not intended by the user may be created depending on a numerical error. In the former method, the fillet portion can be simplified, but other features such as holes and chamfers cannot be simplified. In the latter method, it is necessary to interactively select individual shape elements to be simplified one by one, and a plurality of shape elements cannot be specified collectively, so that the number of steps for creating a simplified model increases.

An object of the present invention is to provide a shape simplification method for solving the above problems and efficiently creating a simplified model for reducing the calculation cost without reducing the analysis accuracy. is there.

[0007]

In order to achieve the above object, the present invention provides a shape model input means for inputting a shape model to be subjected to numerical analysis to a computer and registering the shape model in a storage device;
Means for inputting a dimension parameter, an area parameter, and a volume parameter for comparing the size of the dimension data, the area data, and the volume data of the features of the shape model as the feature to be removed; Means for entering keywords,
Means for directly inputting whether or not to remove the feature;
Model simplification process registration means for registering the input dimension parameter, area parameter, volume parameter, feature name keyword, and procedural data directly specifying whether or not to remove the feature in a database as shape simplification process data, Means for reading the shape simplification process data registered in the database; means for automatically searching for features having dimensions smaller than the registered dimension parameters; and automatically retrieving features having areas smaller than the registered area parameters. Means for searching; means for automatically searching for features having a volume smaller than the registered volume parameter; means for automatically searching for features having a name that includes or matches the registered keyword; Fee with or without Means for automatically searching the simplified feature database, means for registering the features corresponding to the search in the simplified feature database, and creation of the simplified model by removing the features registered in the simplified feature database. Is stored in the storage device.

Further, when the shape of the shape model is changed,
There is also provided a tracing means capable of applying the shape simplification process data before the shape change to the shape model after the shape change. In the shape model simplification unit, an analysis result registration unit that performs a numerical analysis on the model after the shape model simplification and registers an identifier of analysis result data obtained by the numerical analysis in a shape simplification process database. Prepare.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 1. Configuration of a Shape Simplification System of the Present Invention and Processing Procedures of Each Component FIG. 1 is a configuration diagram showing an embodiment of the shape simplification apparatus. This system inputs a shape model to a computer and registers it as shape model data 111 and feature data 112. The size data, area data, and volume data of the features of the shape model are large or small as features to be removed. Simplification including means for inputting a dimension parameter, an area parameter, and a volume parameter for comparing, a means for inputting a keyword of a name of a feature to be removed, and a means for directly inputting whether or not to remove a feature It has a feature search parameter input unit 104.

For example, search parameters are input on an input screen as shown in FIG. Here, the features to be removed by the dimension parameter, the area parameter, and the volume parameter are often fillets, chamfers, holes, and notches, which do not affect the analysis accuracy. Can be specified.

For example, as shown in FIG. 3, when the fillet is removed, when the radius 301 of the fillet is equal to or smaller than the dimension parameter input by the user, the shape is changed to a shape such as 302. A fillet radius is 201 as a fillet dimension parameter, a chamfer dimension is 202 as a chamfer dimension parameter, and a hole contour area is 2 as a hole area parameter.
03, the volume of the notch is 2 as the volume parameter of the notch
04, the keyword of the name of the feature is further input to 205, the button 206 and the mouse pointer 210 designate that the feature is directly removed, and the button 207 designates that the feature is not directly removed. Specified with the mouse pointer 210.

Further, there is provided a shape simplification process database 105 for holding the procedure data designated by the simplified feature search parameter input unit 104 together with the model identifier of the input shape model as shape simplification process data.

A simplified feature search unit 106 reads the shape simplified process data registered in the shape simplified process database 105 and searches for a feature to be simplified. It has a simplified feature database 115 that is maintained as simplified features. A simplified model creation unit 107 that removes a feature registered in the simplified feature database 115 from the shape model and registers it as simplified model data 114, and simplified model data 114.
A numerical analysis mesh creating unit 108 that generates a numerical analysis mesh and registers it as mesh data 113, and a numerical analysis processing unit 1 that performs a numerical analysis based on the mesh data 113.
09, an analysis error before performing the shape model simplification and a numerical analysis after the shape model simplification, comparing the obtained analysis results, and registering a difference between the two cases of analysis results in the shape simplification process database 105. It comprises a registration unit 110.

By providing the shape simplification process database 105 and the simplification feature database 115 to the shape simplification device in the conventional shape simplification method, a simplified model can be more easily created for the shape model after the shape change. It has become. Further, the analysis result after the shape simplification can be referred to. The processing procedure in each component of the system will be described below.

In the shape model input unit 103, the user creates and changes a shape model based on the input data by using the keyboard 101b and the mouse 101c of the input / output device 101 via the input / output control unit 102. It is registered as data 111 and feature data 112 and displayed on the display 101a.

Simplified feature search parameter input unit 1
In the input screen 04, the user uses the keyboard 101b and the mouse 101c of the input device 101 on the input screen shown in FIG. For the data, a dimensional parameter, an area parameter, and a volume parameter for comparing the size as a feature to be removed, a keyword of the name of the feature to be removed, and the presence / absence of direct removal of the feature are input. Further, the procedure designated by the simplified feature search parameter input unit 104 is registered in the simplified shape process database 105 as simplified process data.

The simplified feature search unit 106 searches for a corresponding feature in the procedure shown in FIG. 4 based on the data input by the simplified feature search parameter input unit 104 in the shape model data 111.

(1) The feature data 112 of the shape model to be simplified is read (ST4-1).

(2) The shape simplification process data is read from the shape simplification process database 105. At this time, when a plurality of shape simplification process data having the same shape model identifier is registered in the shape simplification database 111, the shape simplification process data of the similar shape model can be selected (ST4-2). .

(3) For all features and objects (4) to (1)
The simplified process data shown in 0) is applied.

(4) If the target feature is specified as a feature that is not directly simplified, it is excluded from the target of the removed feature (ST4-3).

(5) If the target feature is specified as a directly simplified feature, it is set as a removal feature target (ST4-4).

(6) When the target feature is a fillet, if the radius of the fillet is smaller than the designated dimension parameter, it is set as a removal feature target (ST4-5).

(7) When the target feature is chamfered, if the dimension of the chamfer is smaller than the specified dimension parameter, it is set as a removal feature target (ST4-6).

(8) When the target feature is a hole, if the contour area of the hole is smaller than the designated area parameter, it is set as a removal feature target (ST4-7).

(9) If the target feature is a notch, and if the volume of the notch is smaller than the designated volume parameter, it is set as a removal feature target (ST4-8).

(10) If the name of the target feature contains the specified keyword or is unique, it is set as the target of the removed feature (ST4-9).

As a result of the search, the corresponding feature is set as a simplified feature in the simplified feature database 1.
Register at 15. In the simplified model creation unit 107, the feature data 112 of the shape model to be simplified.
Is read, the feature that matches the simplified feature registered in the simplified feature database 115 is removed, and the simplified model after the removal is referred to as simplified model data 1
Register as 14.

The numerical analysis mesh generation unit 108 generates a numerical analysis mesh in the simplified model 115 and registers it as mesh data 113.

The numerical analysis processing unit 109 performs a numerical analysis based on the mesh data, and outputs the result to the analysis result data 11.
Save as 4.

The analysis error registration unit 110 performs a numerical analysis on the model after the shape model simplification, and registers the identifier of the obtained analysis result data in the shape simplification process data.

2. Example of Creating a Simplified Model Using the Shape Simplification System of the Present Invention Next, an example of creating a simplified model using the shape simplification system of the present invention will be described.

A case where a simplified model is created for the shape model shown in FIG. 5 will be described.

When the user selects the button 501, an input screen as shown in FIG. 2 is displayed as the simplified feature search parameter input unit 104. The user sets the fillet radius to 20 as a simplified fillet size parameter.
1. The chamfer dimension is 20 as the chamfer dimension parameter.
2. The area of the hole contour is 203 as the hole area parameter,
The volume of the notch is 204 as the volume parameter of the notch,
The name of the feature to be simplified is designated by 205. When the button 206 is selected, a simplified feature can be designated by the mouse pointer 210, and when the button 207 is selected, a non-simple feature can be designated by the mouse pointer 210. The designation of the simplified feature is confirmed with the button 208, and the button 209 is canceled. After confirming the designation of the simplified feature, the system registers the designated procedure in the shape simplified process database 105.

Subsequently, a feature is searched by the procedure shown in FIG. 4, the corresponding feature is registered as a simplified feature in the simplified feature database 115, the registered feature is removed from the shape model, and the shape after the removal is simplified. Register as a model (FIG. 6). After that, a mesh for numerical analysis is created, numerical analysis is performed based on the mesh data 113, and registered as analysis result data 116.
Thereafter, the system registers the difference between the analysis result of the shape model before the shape simplification and the analysis result of the simplified model in the shape simplification process database 105 as an analysis error.

After the series of processes described above, when a simplified model in which the shape is changed is created as shown in FIG. 7, the shape can be simplified by the method described above. However, many operations are performed before the shape change, and the user's labor increases. Therefore, a simplified model can be automatically created for the shape model after the shape change using the shape simplification process data before the shape change.

When the user selects the button 701, the system searches the shape simplification process database 105 for shape simplification process data having the same shape model identifier as the target shape model. In this case, since the shape simplification process data before the shape change is registered, FIG.
And the analysis result 802 of the shape 801 before the shape change and the simplified shape are displayed. Here, when there are a plurality of shape simplification process data having the same shape model identifier,
When the button 803 and the button 804 are selected, registered simple models and their analysis results can be sequentially displayed.

A button 805 is selected to determine the shape simplification process, and a button 806 is selected to cancel it. After confirming the shape simplification process, the system applies the shape simplification process data registered in the shape model,
A feature is searched by the procedure shown in FIG. 4, the corresponding feature is registered as a simplified feature in the simplified feature database 115, the registered feature is removed from the shape model, and the shape after the removal is shown in the simplified model (FIG. 9). 1
Register as 14. Thereafter, a mesh for numerical analysis is created, numerical analysis is performed based on the mesh data, and the result is stored as analysis result data. After that, the system registers the identifier of the analysis result data of the simplified model in the shape simplification process database 105.

[0039]

According to the method of the present invention, features that do not affect the analysis accuracy in the shape model can be simplified. Further, even when the shape is changed, a simplified model can be easily created. Thereby, the shape for the numerical analysis can be simplified in a short time, and the number of meshes and the numerical analysis time can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of the present shape model simplification apparatus.

FIG. 2 is a designation screen for simplifying a shape.

FIG. 3 is a diagram showing an example of simplified feature parameters and simplified shapes.

FIG. 4 is a flowchart of a simplified feature search unit.

FIG. 5 is a perspective view showing an example of a shape model to be simplified.

FIG. 6 is a perspective view showing an example of a simplified model.

FIG. 7 is a perspective view showing an example of a shape model after a shape change.

FIG. 8 is a perspective view showing an example of a shape simplification process data selection screen.

FIG. 9 is a perspective view showing an example of a simplified model after a shape change.

[Explanation of symbols]

101: input / output device, 101a: display, 101
b ... keyboard, 101c ... mouse.

Claims (1)

[Claims] 1. A method for inputting a shape model to be subjected to numerical analysis to a computer, creating a mesh for numerical analysis on the shape model, and performing a numerical analysis based on the mesh for numerical analysis. When the shape is changed, a shape simplification procedure data set before the shape change is read from a database, the simplification procedure is applied to the changed shape model, and a simplified model is created. Simplification method.