JPH0822484A - Device and method for automatically dividing element - Google Patents

Abstract

PURPOSE:To provide a highly accurate analyzed result in element division for which the size and shape of elements are uniform. CONSTITUTION:At the time of performing the design analysis of a structure obtained by a CAD system by a finite element method, the nodes of equal pitches are generated along the boundary line of the display shape of the structure (S2) and respective vertical lines vertical to the boundary line passing through the respective nodes are generated (S3). The respective nodes are generated at equal pitch positions in the inside from the boundary positions on the respective vertical lines (S4), obtained respective contact points are connected, the parallel line of the boundary line is generated and then, an element division line is automatically generated based on the boundary line, the respective vertical lines and the parallel line (S5).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic element dividing apparatus and method used when performing numerical simulation by a finite element method model in design analysis of a structure.

[0002]

2. Description of the Related Art For example, when structural analysis is performed on a structure obtained by a three-dimensional CAD device by numerical simulation using a finite element method model, conventionally, CAD is used.
From the shape display on the device, the elements are divided uniformly without paying attention to the distance between the nodes without distinguishing the boundary or the inside of the structure. Therefore, the automatic setting is not made by intentionally changing the boundary and inner node patterns.

[0003]

The above-mentioned conventional apparatus has the following problems. That is, on the boundary line of the finite element method model, although the nodes are divided into equal pitches, etc., consideration is given to the inside, but no regular restrictions are applied to the inside, and the shapes and sizes of the elements are uneven. There is. And, there are many cases where the boundary is constrained or a load is applied, and the flow of force along the shape also becomes a problem in structural analysis, so that the shape and size of the elements are not uniform as described above. Negative for evaluation of analysis results.

The present invention has been made in view of the above situation, and the finite element method automatic element dividing device capable of obtaining a highly evaluated analysis result because the shapes and sizes of the elements are almost the same. And to provide a method.

[0005]

That is, the present invention provides a CA
When the design analysis of the structure obtained by the D device is performed by the finite element method, the first generating means for generating the nodes of equal pitch along the boundary line of the display shape of the structure, and the first generating means. Second generating means for generating perpendicular lines perpendicular to the boundary line passing through the nodes obtained by the means, and the nodes at equal pitch positions inward from the boundary positions on the perpendicular lines obtained by the second generating means. It is provided with a third generating means for generating and a fourth generating means for connecting the respective contacts obtained by the third generating means to generate a parallel line of the boundary line, the boundary line, each perpendicular line and the parallel line. The element dividing line is automatically generated based on the line.

[0006]

With the above-mentioned configuration, the element can be divided into elements having the same size and shape along the boundary shape.
It is possible to obtain highly accurate analysis results.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the relationship with a peripheral device according to an embodiment of the present invention. In the figure, 11 is a two-dimensional CAD or three-dimensional CA used to input a structural shape for design.
This is a structural shape inputting CAD device by D, and the recognition data of the coordinates and the surface representing the structural shape input by the structural shape inputting CAD device 11 are sent to the design analysis device 12.

This design analysis device 12 is a structure shape input CA.
Numerical values required for structural strength design analysis, thermal design design analysis, sound field design analysis, magnetic field design analysis, etc. are obtained by simulation with respect to the input from the D device 11 and the respective numerical values are input by the structural shape input CAD device 11. The data is supplied to the automatic element dividing device 13 of the finite element method model according to the present invention together with the recognition data of the coordinates and the surface representing the formed structural shape.

The automatic element dividing device 13 divides the structure into elements having the same size and shape along the boundary shape by the processing described later, and the divided elements are divided into the design analyzing device 12 described above.
It is sent to the analysis calculation device 14 together with the input from.

In this analysis calculation device 14, the structural shape input C
Each analysis described above based on the recognition data of the coordinates and the surface representing the structural shape input by the AD device 11, the simulation numerical value obtained by the design analysis device 12 and the dividing element of the structural shape obtained by the automatic element dividing device 13. To perform calculations,
Various data obtained as a result of the calculation are output by the data output device 15 and fed back to the design.

With the above-mentioned structure, the operation of element division by the automatic element division device 13 will be described below with reference to FIGS. 2 and 3. FIG. 2 is a flow chart showing the processing contents by the automatic element dividing device 13. When the design analyzing device 12 inputs the simulation numerical values and the recognition data of the coordinates and the surface representing the structural shape, and the instruction of the element division is given, the automatic element dividing device 13 First, as shown in step S1, the step 13 reads the coordinates representing the structural shape and the recognition data of the surface and stores them.

Next, as shown in step S2, the boundary line in the stored structural shape is recognized, and the recognized boundary line is divided and calculated so as to have a substantially equal pitch. A node is generated and numbered at each divided position obtained by this calculation, and the position coordinates of each node are stored in combination with the number.

After that, as shown in step S3, a perpendicular line that passes through each of the boundary nodes and intersects the boundary tangent line at a right angle is generated by calculation, and the inside and outside of the boundary are discriminated, so that it is positioned within the boundary. Stores vertical line data.

Then, as shown in step S4, each vertical line is divided and calculated so as to have a substantially equal pitch from the boundary, nodes are generated and numbered at each divided position obtained by the calculation, and the position coordinates of each node are calculated. Is stored as a pair with the number.

FIG. 3 (1) illustrates the above processing on an actual structural shape. BL is a boundary line, a point P on the boundary line BL is a node, and only one of the nodes P is a boundary. Border line B
A line TL in contact with L is a tangent line, a line PL perpendicular to the tangent line TL is a perpendicular line, and points P at substantially equal pitches inside the shape from the boundary line BL on the perpendicular line PL are nodes.

Next, as shown in step S5, the distances between the nodes generated in the boundary are calculated, and the nodes at approximately equal pitches are compared to classify the nodes. The peripheral elements defined by the nodes on the boundary are numbered and the corresponding node numbers are stored.

FIG. 3B shows an example of the nodes generated around the boundary when the structural shape is rectangular. Based on this, the dividing element generated using only the nodes around the boundary is a diagram. 3 (3).

After that, as shown in step S6, nodes other than the periphery of the boundary are generated, the distances between the nodes are calculated only for those inside the boundary, and the nodes are compared and compared to each other. The divided elements obtained by connecting the remaining nodes after classification are numbered and the corresponding node numbers are stored.

FIG. 3 (4) illustrates the case where the nodes are generated in the area IA further inside the rectangular peripheral area BA by the processing of step S6, and when the division element is generated based on this, FIG. As shown in (5).

Then, as shown in step S7, in order to collectively synthesize the nodes and elements of the entire area, the node numbers and the element numbers are sequentially arranged, and the node coordinates and the node numbers corresponding to the element numbers are stored.

According to the contents stored at this point, a divided element having a structural shape in which the nodes and elements of the entire region are integrated and synthesized is created as shown in FIG. 3 (6). Assuming that the automatic element division processing has been completed as described above, the division element data as the structural data of the finite element method is output to the analysis calculation device 14 in the next stage as shown in step S8, and the analysis calculation is executed to execute this processing. Is to end.

[0022]

As described above, according to the present invention, a finite element method model capable of contributing to the improvement of analysis accuracy by enabling element division in which element sizes and shapes are aligned along the boundary shape. An automatic element dividing device and method can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a relationship with peripheral devices according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation according to the embodiment.

FIG. 3 is a diagram for explaining the operation according to the embodiment.

[Explanation of symbols]

11 ... CAD device for inputting structural shape, 12 ... Design analysis device, 13 ...
Automatic element dividing device, 14 ... Analytical calculation device, 15 ... Data output device.

Claims (2)

[Claims] 1. When a design analysis of a structure obtained by a CAD device is performed by a finite element method, nodes having an equal pitch are generated along a boundary line of the display shape of the structure.
Generating means, second generating means for generating each vertical line perpendicular to the boundary line passing through each node obtained by the first generating means, and boundary position on each vertical line obtained by the second generating means. A third generating means for generating the nodes at equal pitch positions from the inside to a fourth generating means for connecting the contact points obtained by the third generating means to generate parallel lines of the boundary line. An automatic element dividing device, comprising: an element dividing line automatically generated based on the boundary line, each perpendicular line and the parallel line. 2. When the design analysis of the structure obtained by the CAD device is performed by the finite element method, the first pitches are generated along the boundary line of the display shape of the structure.
Generation processing, a second generation processing for generating each vertical line perpendicular to the boundary line passing through each node obtained in this first generation processing, and a boundary position on each vertical line obtained in this second generation processing. A third generating process for generating nodes at equal pitch positions from the inside to a fourth generating process for connecting the contact points obtained in the third generating process to generate parallel lines of the boundary line. An automatic element dividing method comprising: automatically generating an element dividing line based on the boundary line, each perpendicular line and the parallel line.