JPH11283050A - Method for generating finite element data and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve the burden of a data input and a data generating parameter input by an operator, to reduce a boundary shape error and to reduce a calculation load by preferentially giving a node number from a direction with less rectangular element dividing numbers in a two-dimensional coordinate axis. SOLUTION: A space area 9 including a body to be an object 8 is processed by division and cut into small cubes. The material numbers of three-dimensional elements which are processed by division are set in the material numbers of blocks including the three-dimensional elements. In this case, two-dimensional cross sections are piled from the one with a smaller Z-coordinate at every plane and three-dimensional element division is generated so that the order of the element numbers and the node numbers becomes the order of size from the one with the small Z-coordinate. At this time, the max. value of difference in the node numbers in the elements of the respective two-dimensional cross sections becomes the number of the nodes of the two-dimensional cross sections before piling. Then, the numbers of the respective nodes are changed into numbering from a direction with the smaller number of division concerning the respective X-axis, Y-axis and Z-axis directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently generating finite element data in a finite element analysis of a target object having a complicated structure, thereby reducing the calculation load and improving the calculation accuracy. And its device.

[0002]

2. Description of the Related Art Generally, the number of operations in an analysis program using the finite element method is based on the maximum difference between node numbers (generally assigned in the input order) of each node constituting one element (this is referred to as a maximum node number difference). ), The method of arranging the node numbers directly affects the operation time, and has a problem that the calculation load increases. However, the input data of the analysis program (this is called finite element data)
Is mainly composed of node information, element information, and analysis information. As the target object becomes more complicated, the number of data becomes enormous. Therefore, the data creator has conventionally created and input the node information in an arbitrary order without considering how to arrange the node information. Alternatively, even if this is taken into consideration, there is a problem that it is difficult to optimally arrange the nodes due to the large amount of node information.

[0003] As means for solving such problems, Japanese Patent Application Laid-Open No. Hei 8-30658 discloses a finite element data creation device, which simplifies the input operation itself of object data to be analyzed. The finite element data is rearranged to reduce the calculation load of the finite element analysis program.

[0004]

However, according to the method disclosed in Japanese Patent Application Laid-Open No. Hei 8-30658, since the target object and the space area can be divided into elements only in a grid pattern, the object is divided into three axes (X, Y, and Z axes). In order to divide a target object such as a triangular prism with non-parallel surfaces into elements, it is difficult to create finite element data near the boundary between the target object and the space area. There was a problem that it was difficult to make.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the burden on the operator for inputting data and inputting parameters for generating finite element data, and based on these inputs, reduce errors in the boundary shape of the object to be analyzed and reduce the computational load. An object of the present invention is to provide a method and an apparatus for creating finite element data that can automatically create legal data.

[0006]

A method for creating finite element data according to a first method of the present invention is a method for creating two-dimensional finite element data of an object to be analyzed by a finite element method.
Setting a two-dimensional region including the object to be analyzed; dividing the two-dimensional region into a plurality of rectangular elements according to a specified number of divisions; and defining sides of the rectangular element in a specified direction. Of the nodes at both ends of the side through which the contour of the object to be analyzed penetrates, a step of translating in the specified direction so as to match the node closer to the contour to the contour; and A step of giving a node number with priority from the direction in which the number of divisions of the rectangular element is small.

According to a second aspect of the present invention, there is provided a method for generating finite element data, comprising the steps of: setting a three-dimensional region including the object to be analyzed in the method for generating three-dimensional finite element data of the object to be analyzed by the finite element method. Dividing the three-dimensional area into a plurality of rectangular parallelepiped elements according to a specified number of divisions; and specifying a rectangular element of a cross-section of the rectangular parallelepiped element in a two-dimensional cross section of the three-dimensional area in a specified direction. Among the nodes at both ends of the side through which the contour of the object to be analyzed penetrates in the specified direction, the node closer to the contour is translated in the specified direction so as to match the contour with the contour. And a step of giving a node number preferentially from a direction in which the number of divisions of the rectangular parallelepiped element is small among the three-dimensional coordinate axes.

[0008] A method for creating finite element data according to a third method of the present invention is a method for creating two-dimensional finite element data of an object to be analyzed by the finite element method, wherein a step of setting a two-dimensional area including the object to be analyzed is performed. Dividing the two-dimensional region into a plurality of rectangular elements in accordance with a designated number of divisions, and, among the rectangular elements, those having an area included in the object to be analyzed of 50% or more are regarded as objects to be analyzed. And a step of giving a node number preferentially from a direction in which the number of divisions of the rectangular element is small among the two-dimensional coordinate axes.

According to a fourth aspect of the present invention, there is provided a method of generating finite element data, comprising the steps of: setting a three-dimensional region including the object to be analyzed in the method of generating three-dimensional finite element data of the object to be analyzed by the finite element method. Dividing the three-dimensional area into a plurality of rectangular parallelepiped elements in accordance with a designated number of divisions; and, among the rectangular parallelepiped elements, those having an area included in the object to be analyzed of 50% or more are regarded as objects to be analyzed. And a step of giving a node number preferentially from a direction in which the number of divisions of the rectangular parallelepiped element is small among the three-dimensional coordinate axes.

In a fifth aspect of the present invention, a method for generating finite element data includes the step of setting a two-dimensional region including an object to be analyzed in the method for generating two-dimensional finite element data of an object to be analyzed by a finite element method. Dividing the two-dimensional region into a plurality of rectangular elements according to a specified number of divisions in a grid, and, among the rectangular elements, those whose nodes are included in two or more analysis target objects are regarded as analysis target objects. And a step of giving a node number preferentially from a direction in which the number of divisions of the rectangular element is small among the two-dimensional coordinate axes.

According to a sixth aspect of the present invention, there is provided a method of generating three-dimensional finite element data of an object to be analyzed by the finite element method, wherein a three-dimensional region including the object to be analyzed is set. Dividing the three-dimensional region into a plurality of rectangular parallelepiped elements according to a designated number of divisions; and, among the rectangular parallelepiped elements, those whose nodes are included in the object to be analyzed four or more, are regarded as the object to be analyzed. And a step of giving a node number preferentially from a direction in which the number of divisions of the rectangular parallelepiped element is small among the three-dimensional coordinate axes.

According to a first aspect of the present invention, there is provided an apparatus for creating finite element data, the apparatus for creating two-dimensional finite element data of an object to be analyzed by a finite element method, wherein a two-dimensional region including the object to be analyzed is set. Means, means for grid-dividing the two-dimensional area into a plurality of rectangular elements according to a specified number of divisions, and sides in the specified direction of the rectangular elements, through which the contour of the object to be analyzed penetrates Means for translating in parallel to the specified direction so that a node closer to the contour line among the nodes at both ends of the rectangle coincides with the contour line, and a direction in which the number of divisions of the rectangular element is smaller among the two-dimensional coordinate axes. And means for assigning a node number with priority to

A finite element data creation device according to a second configuration of the present invention is a device for creating three-dimensional finite element data of an object to be analyzed by a finite element method, wherein a three-dimensional region including the object to be analyzed is set. Means, means for grid-dividing the three-dimensional area into a plurality of rectangular parallelepiped elements in accordance with a specified number of divisions, and, in a two-dimensional cross section in a specified direction of the three-dimensional area, a rectangular element having a cross section of the rectangular parallelepiped element Of the sides in the specified direction, of the nodes at both ends of the side through which the contour of the object to be analyzed penetrates, translate in the specified direction so that the node closest to the contour matches the contour. And a means for preferentially assigning a node number from a direction in which the number of divisions of the rectangular parallelepiped element is small among the three-dimensional coordinate axes.

According to a third aspect of the present invention, there is provided a finite element data creating apparatus for creating a two-dimensional finite element data of an object to be analyzed by a finite element method, wherein the two-dimensional area including the object to be analyzed is set. Means, means for grid-dividing the two-dimensional area into a plurality of rectangular elements according to a specified number of divisions, and, among the rectangular elements, those having an area included in the object to be analyzed of 50% or more are regarded as objects to be analyzed. And a means for preferentially assigning a node number from a direction of a smaller number of divisions of the rectangular element among the two-dimensional coordinate axes.

According to a fourth aspect of the present invention, there is provided an apparatus for generating three-dimensional finite element data of an object to be analyzed by a finite element method, wherein the three-dimensional area including the object to be analyzed is set. Means, means for grid-dividing the three-dimensional region into a plurality of rectangular parallelepiped elements according to a specified number of divisions, and, among the rectangular parallelepiped elements, those having an area included in the object to be analyzed of 50% or more are defined as objects to be analyzed. And a means for preferentially assigning node numbers to directions of the three-dimensional coordinate axes in which the number of divisions of the rectangular parallelepiped element is small.

According to a fifth aspect of the present invention, there is provided an apparatus for creating finite element data, the apparatus for creating two-dimensional finite element data of an object to be analyzed by a finite element method, wherein a two-dimensional region including the object to be analyzed is set. Means, means for grid-dividing the two-dimensional area into a plurality of rectangular elements according to a specified number of divisions, and, among the rectangular elements, those whose nodes are included in the object to be analyzed two or more as the object to be analyzed. And a means for preferentially assigning a node number from a direction of a smaller number of divisions of the rectangular element among the two-dimensional coordinate axes.

According to a sixth aspect of the present invention, there is provided an apparatus for generating finite element data, the apparatus for generating three-dimensional finite element data of an object to be analyzed by the finite element method, wherein a three-dimensional region including the object to be analyzed is set. Means, means for grid-dividing the three-dimensional area into a plurality of rectangular parallelepiped elements in accordance with a specified number of divisions, and among the rectangular parallelepiped elements, those whose nodes are included in the object to be analyzed by four or more. And a means for preferentially assigning node numbers to directions of the three-dimensional coordinate axes in which the number of divisions of the rectangular parallelepiped element is small.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram of an apparatus used for implementing the present invention. In FIG.
An input device 1 includes a keyboard, a mouse, a scanner, and the like. 2 is a CPU, according to a program,
It creates and processes finite element data, which will be described later, and controls each component connected to the bus 7. Reference numeral 3 denotes a display device such as a CRT, which is used at the time of data input work and confirmation of input information. Reference numeral 4 denotes a program memory, which is a memory for storing a control program operating on the CPU 2. Reference numeral 5 denotes a data memory for storing data generated in various processes. Reference numeral 6 denotes an external storage device for storing data of the created finite element model. Further, data or a processing program to be subjected to element division may be read from the external storage device 6. 7
Is a bus for transferring an address signal indicating a component to be controlled by the CPU 2, a control signal for controlling each component, and data exchanged between components.

Next, the operation of the first embodiment will be described with reference to FIGS.
This will be described with reference to FIG. When creating three-dimensional finite element data, translate the rectangular elements near the contour of the target object that are not parallel to the rectangular element to the contour of the target object so that the nodes that make up the rectangular element match the shape of the target object A method for performing the above will be described. FIG. 2 is a flowchart showing a processing procedure of the present method. Here, a triangular prism target object 8 as shown in FIG. 3 will be described. In the electromagnetic field analysis, not only the target object but also the spatial region 9 around it
Also needs to be divided into elements.

First, the operator selects the most complicated two-dimensional section. As criteria for selecting a complicated two-dimensional cross section, there are many objects having different physical property values on the cross section, and there are many irregularities on the object. The most complicated cross section in FIG. 3 is the XY plane including the target object. FIG. 4A is an explanatory diagram of a cross section created by an operator.

<Steps S1 and S2> The operator uses the sectional view as shown in FIG.
The vertex coordinate table shown in (b), the material number for each block shown in (c), and the constituent vertex number table are input.

<Step S3> Lines parallel to the X, Y, and Z axes of the contour of the target object are automatically extended on the apparatus, and the block is subdivided. FIG. 5 is an explanatory diagram of a subdivided block.

<Steps S4 to S5> The operator inputs the number of divisions in the X and Y directions to the apparatus.
At this time, the line segment divided into the lattice shape always includes the boundary of the block parallel to the X axis and the Y axis. FIG. 6 (a)
Indicates that the operator is between vertex numbers 7-11, 11-1 in FIG.
It is an explanatory view of a state where the number of divisions between 1-10 and 10-2 is input and divided into lattice-like elements using rectangular elements.
Assuming that the rectangular element is composed of nodes, the coordinates of the node, the material number of the rectangular element, and the number of the composing node constituting the rectangular element are stored in the device (FIG. 6B,
(C)).

<Step S6> The apparatus automatically performs the following processing. (1) The material number of the rectangular element included in the target object 8 at all is set as the material number of the target object 8. (2) The material numbers of the remaining rectangular elements are used as the material numbers of the space area 9. FIG. 7 is an image of this operation, in which the element indicated by ● represents the target object 8 and the element indicated by ○ constitutes the space area 9. (3) The device stores the element number through which the contour of the target object that is not parallel to the X or Y axis penetrates and the intersection of the contour and the side of the rectangular element in the device. (4) In the rectangular elements stored in (3), among the constituent nodes at both ends of the line segment intersecting with the contour of the target object 8, the coordinates of the constituent nodes whose distance to the intersection with the contour is short and the intersection with the contour are determined. Translate to The direction of the parallel movement is a direction in which the number of intersections between the rectangular element and the contour is small in the X and Y directions (FIG. 8). (5) The material number of the rectangular element having two or more constituent nodes not included in the target object 8 is changed to the material number of the space area 9 (FIG. 9). (6) The rectangular element that is traversed by the outline of the target object 8 is divided into two triangular elements each having the outline of the target object 8 as one side. (7) Among the triangular elements, the material numbers of the elements whose constituent nodes are not all included in the target object 8 are changed to the material numbers of the space area 9 (FIG. 10).

<Step S7> Next, the apparatus is subjected to input processing of the vertex coordinates of the block in the height (Z) direction, the material number, and the number of divisions for each block.

<Step S8> The apparatus automatically performs the following operations. (1) The spatial area 9 including the target object 8 is divided into dice. When the two-dimensional element is a rectangle, the three-dimensional elements stacked in the height (Z) direction become a rectangular parallelepiped, and when the two-dimensional element is a triangle, the three-dimensional element becomes a triangular prism. (2) The material number of the divided three-dimensional element is set to the material number of a block including the three-dimensional element. FIG. 11 (a)
Is Y = 66.6 to 73.3 in the element division diagram after the three-dimensional division.
Is an XZ plane of the cross section of (a), (A) and (B) in the element are the material numbers of each element. FIGS. 11B and 11C temporarily store the data in the data memory 5.

At this time, two-dimensional sections are stacked for each plane from the smaller Z coordinate to create a three-dimensional element division. Therefore, the order of element numbers and node numbers is from the smallest Z coordinate to the largest. At this time, the maximum value of the difference between the node numbers of the elements in each of the two-dimensional cross sections (this is referred to as “maximum node number difference”) is substantially equal to the number of nodes of the two-dimensional cross section before being stacked. For example, the maximum node number difference in FIG.
83. Data corresponding to FIGS. 11B and 11C is created and stored in the external storage device 6.

<Step S9> The number of each node is set on the X axis,
For each of the Y-axis and Z-axis directions, the numbering is changed from the direction in which the number of divisions is small (this is called “small order of division number”). 12A and 12B are examples in which the node numbers are numbered in the order of the Z axis, the X axis, and the Y axis, and the maximum node number difference is 1
It becomes 18. By the operation in step S9, step S8
, The maximum node number difference decreases from 183 to 118.

As described above, according to this embodiment, the burden on the operator for inputting data and inputting parameters for finite element method data creation is small, and errors in the boundary shape of the object to be analyzed are based on these inputs. And the finite element method data with a small calculation load can be automatically created. In particular, in this embodiment, since a calculation model that matches the boundary of the target object that is not parallel to the coordinate axis is created, an error due to the boundary shape is extremely small.

Embodiment 2 FIG. In the creation of the two-dimensional finite element data of FIG. 13, a method using a means for moving nodes constituting a rectangular element so that a rectangular element near the contour of the target object that is not parallel to the rectangular element matches the shape of the target object explain. In the figure, 10 is a target object, and 11 is a space area.

Steps S1 to S1 shown in FIG.
6 are performed in the same manner as in the first embodiment. FIGS. 4 to 10 are referred to. Next, in step 9, the numbering of each node is changed in the X-axis and Y-axis directions in ascending order of the division number. In the case of FIG. 10, the node numbering is Y axis,
The order of the X axis is changed to the order of the X axis and the Y axis, and the maximum node number difference decreases from 15 to 13.

Embodiment 3 FIG. In the creation of the two-dimensional finite element data of FIG. 13, when the area of the rectangular element near the contour of the target object that is not parallel to the rectangular element is included in the target object by 50% or more, the element is divided into grids by the rectangular element. A method using a means for determining a target object will be described. FIG. 14 is a flowchart showing the processing procedure of this method.

First, steps S1 to S5 are performed. The operation from step S1 to step S5 is the same as the flowchart in FIG. In step S11, the material number of the rectangular element whose area is included in the target object by 50% or more of the rectangular element is set as the material number of the target object (FIG. 15). In step S12, the numbering of the nodes is changed in the X-axis and Y-axis directions in ascending order of the number of divisions. In the case of FIG. 15, the node numbers are numbered in the order of the X axis and the Y axis, and the maximum node number difference is 13. In step 11 of this embodiment, when the center of gravity of the rectangular element is included in the target object, the element may be determined to be the target object.

As described above, according to this embodiment, the burden on the operator for inputting data and inputting parameters for data creation is small, and based on these inputs, errors in the boundary shape of the object to be analyzed are small. Finite element method data with low calculation load can be created automatically.

Embodiment 4 FIG. In the creation of the three-dimensional finite element data of FIG. 3, when the volume of the rectangular parallelepiped element near the boundary surface of the target object that is not parallel to the rectangular parallelepiped element is included in the target object by 50% or more, the element is divided into grids by the rectangular parallelepiped element. A method using a means for determining a target object will be described.

In this case, FIG.
Steps S1 to S5, S11, and S12 can be easily performed simply by extending them from two-dimensional to three-dimensional. Step 1 of this embodiment
In 1, when the center of gravity of a rectangular parallelepiped element is included in the target object, the element may be determined to be the target object.

Embodiment 5 In the creation of the two-dimensional finite element data of FIG. 13, when the target object includes two or more constituent nodes of the rectangular element near the contour of the target object that is not parallel to the rectangular element, A method of using a means adopted as a target object will be described. FIG. 14 is a flowchart showing the processing procedure of this method.

First, the operation from step S1 to step S5 is performed. The operation from step S1 to step S5 is the same as in the third embodiment. Is the same as In step S11, when two or more constituent nodes of the rectangular element are included in the target object, the material number of the element is set as the material number of the target object (FIG. 15). Although the determination means is different from that of the third embodiment, similar results are obtained. In step S12, the numbering of each node is changed in the X-axis and Y-axis directions in ascending order of the number of divisions as in the third embodiment. In the case of FIG. 15, the node numbers are numbered in the order of the X axis and the Y axis, and the maximum node number difference is 13.

As described above, according to this embodiment, the burden on the operator for inputting data and inputting data creation parameters is small, and errors in the boundary shape of the object to be analyzed are small based on these inputs. Finite element method data with low calculation load can be created automatically.

Embodiment 6 FIG. In the creation of the three-dimensional finite element data of FIG. 3, when the target object includes four or more constituent nodes of a rectangular parallelepiped element near the contour of the target object that is not parallel to the rectangular parallelepiped element, A method of using a means adopted as a target object will be described.

In this case, FIG. 14 shown in Embodiment 5
Steps S1 to S5, S11, and S12 can be easily performed simply by extending them from two-dimensional to three-dimensional.

Embodiment 7 Although the first embodiment is a case where the target object is parallel to the Z axis, the present invention can be applied to a case where the target object is not parallel to the Z axis. An object having a triangular cross section having different sizes in the Z direction as shown in FIG. 16 will be described. FIG. 17A shows the upper surface of the target object,
(B) is a lower surface of the target object, and steps S1 to S8 in FIG. 2 are executed for these two types of surfaces. In step 4, the values of the division number inputs in FIGS. 17A and 17B are made to match. In step 5, when calculating the coordinate values of the sides of the three-dimensional element that are not parallel to the Z direction, the coordinates are linearly approximated from the coordinates of the upper surface (a) and the lower surface (b) of the target object. The numbering in step 9 can be performed in a similar procedure even if it is irregular.

Embodiment 8 FIG. The present invention can be applied to a case where the shape of the target object is not uniform in the height (Z) direction, which is not included in the first and second embodiments. The target object as shown in FIG. 18 will be described. As shown in FIGS. 19A to 19C, the block is divided into two as shown in FIGS. 19A and 19B so that different cross sections in the height (Z) direction can be considered. Steps 1 to 9 in FIG. 2 are executed in advance.

[0044]

As described above, according to the method and apparatus for generating finite element data by the first method and configuration of the present invention, two-dimensional finite element data of an object to be analyzed is generated by the finite element method. Setting a two-dimensional region including the object to be analyzed, dividing the two-dimensional region into a plurality of rectangular elements according to a specified number of divisions, and analyzing the sides of the rectangular elements in a specified direction, Of the nodes at both ends of the side through which the contour of the target object penetrates, translate in the specified direction so that the node closer to the contour matches the contour, and move the rectangle out of the two-dimensional coordinate axes. Since node numbers are assigned with priority from the direction in which the number of element divisions is small, the burden on the operator for inputting data and inputting data creation parameters is small, and the analysis target is based on these inputs. Body error is very small border shape, less computationally intensive FEM data can be automatically created.

A method and apparatus for creating finite element data according to the second method and configuration of the present invention is for creating three-dimensional finite element data of an object to be analyzed by a finite element method. Set the area,
The three-dimensional area is lattice-divided into a plurality of rectangular parallelepiped elements according to a specified number of divisions, and in a two-dimensional cross section in a specified direction of the three-dimensional area, a rectangular element in a cross section of the rectangular parallelepiped element in a specified direction Of the nodes at both ends of the side through which the contour of the object to be analyzed penetrates, the node is moved in parallel in the designated direction so that the node closer to the contour matches the contour, and the three-dimensional Since the node numbers are preferentially assigned to the coordinate axes in the direction in which the number of divisions of the rectangular parallelepiped element is small, the burden on the operator for inputting data and inputting data creation parameters is small, and the analysis target is based on these inputs. The error of the boundary shape of the object is extremely small,
Finite element method data with low calculation load can be created automatically.

A method and an apparatus for creating finite element data according to the third method and configuration of the present invention are for creating two-dimensional finite element data of an object to be analyzed by a finite element method. Set the area,
The two-dimensional area is grid-divided into a plurality of rectangular elements according to a specified number of divisions, and among the rectangular elements, those having an area included in the object to be analyzed of 50% or more are regarded as objects to be analyzed, Since the node numbers are preferentially assigned to the coordinate axes from the direction in which the number of divisions of the rectangular element is small, the burden on the operator for inputting data and inputting data creation parameters is small, and the analysis target is based on these inputs. The finite element method data with a small calculation load and small errors in the boundary shape of the object can be automatically created.

A method and an apparatus for creating finite element data according to a fourth method and configuration of the present invention are for creating three-dimensional finite element data of an object to be analyzed by a finite element method. Set the area,
The three-dimensional area is divided into a plurality of rectangular parallelepiped elements according to a designated number of divisions, and among the rectangular parallelepiped elements, those having an area included in the object to be analyzed of 50% or more are regarded as the object to be analyzed. Since the node numbers are preferentially assigned to the coordinate axes in the direction in which the number of divisions of the rectangular parallelepiped element is small, the burden on the operator for inputting data and inputting data creation parameters is small, and the analysis target is based on these inputs. The finite element method data with a small calculation load and small errors in the boundary shape of the object can be automatically created.

A method and apparatus for creating finite element data according to the fifth method and configuration of the present invention is for creating two-dimensional finite element data of an object to be analyzed by the finite element method. Set the area,
The two-dimensional area is grid-divided into a plurality of rectangular elements according to a specified number of divisions, and among the rectangular elements, those whose nodes are included in the object to be analyzed two or more are regarded as objects to be analyzed, Since the node numbers are preferentially assigned to the coordinate axes from the direction in which the number of divisions of the rectangular element is small, the burden on the operator for inputting data and inputting data creation parameters is small, and the analysis target is based on these inputs. The finite element method data with a small calculation load and small errors in the boundary shape of the object can be automatically created.

According to a sixth aspect of the present invention, there is provided a method and apparatus for creating finite element data according to the sixth method and configuration, wherein three-dimensional finite element data of an object to be analyzed is created by a finite element method. Set the area,
The three-dimensional area is grid-divided into a plurality of rectangular parallelepiped elements according to a specified number of divisions, and among the rectangular parallelepiped elements, those whose nodes are included in the object to be analyzed four or more are regarded as objects to be analyzed, and three-dimensional Since the node numbers are preferentially assigned to the coordinate axes in the direction in which the number of divisions of the rectangular parallelepiped element is small, the burden on the operator for inputting data and inputting data creation parameters is small, and the analysis target is based on these inputs. The finite element method data with a small calculation load and small errors in the boundary shape of the object can be automatically created.

[Brief description of the drawings]

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

FIG. 2 is an operation flowchart showing an operation sequence according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a target object and a spatial region used in the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of target object data input to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an intermediate state of element division according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating an intermediate state of element division according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram for determining a material number of an element in the first embodiment of the present invention.

FIG. 8 is a diagram illustrating movement of node coordinates according to the first embodiment of the present invention.

FIG. 9 is an explanatory diagram for determining a material number of an element in the first embodiment of the present invention.

FIG. 10 is an explanatory diagram for determining element division and element numbers of elements in Embodiment 1 of the present invention.

FIG. 11 is a diagram illustrating three-dimensional element division in the first embodiment of the present invention.

FIG. 12 is an explanatory diagram of an information storage table after node rearrangement in the first embodiment of the present invention.

FIG. 13 is an explanatory diagram of a target object and a spatial region used in Embodiment 2 of the present invention.

FIG. 14 is an operation flowchart showing an operation sequence according to the third embodiment of the present invention.

FIG. 15 is an explanatory diagram for determining a material number of an element in the third embodiment of the present invention.

FIG. 16 is an explanatory diagram of a target object and a spatial region used in Embodiment 7 of the present invention.

FIG. 17 is a diagram illustrating input data used in the seventh embodiment of the present invention.

FIG. 18 is an explanatory diagram of a target object and a spatial region used in Embodiment 8 of the present invention.

FIG. 19 is a diagram illustrating input data used in the eighth embodiment of the present invention.

[Explanation of symbols]

1 input unit, 2 CPU, 3 output unit, 4 program memory, 5 data memory, 6 external storage device, 7 bus, 8, 10 target object, 9, 11 space area.

Claims (12)

[Claims] 1. A method for creating two-dimensional finite element data of an object to be analyzed by a finite element method, comprising the steps of: setting a two-dimensional area including the object to be analyzed; Grid-dividing into rectangular elements, and, among the nodes in both sides of the rectangular element in the designated direction and through which the outline of the object to be analyzed penetrates, the nodes closer to the outline are contoured. Finite element data comprising a step of translating in the designated direction so as to match a line, and a step of giving a node number preferentially from a direction in which the number of divisions of the rectangular element is smaller among two-dimensional coordinate axes. How to create 2. A method for creating three-dimensional finite element data of an object to be analyzed by a finite element method, comprising the steps of: setting a three-dimensional area including the object to be analyzed; Grid dividing into rectangular parallelepiped elements, and, in a two-dimensional cross section in a specified direction of the three-dimensional region, a side in a specified direction of a rectangular element of a cross section of the rectangular parallelepiped element, and a contour line of an object to be analyzed. Among the nodes at both ends of the side penetrating through, a step of translating in the specified direction so that a node closer to the contour line coincides with the contour line, and dividing the rectangular parallelepiped element among the three-dimensional coordinate axes A method for creating finite element data, comprising: a step of giving a node number preferentially from a small number of directions. 3. A method for creating two-dimensional finite element data of an object to be analyzed by a finite element method, comprising the steps of: setting a two-dimensional region including the object to be analyzed; Dividing the rectangular element into lattice elements, of which the area included in the object to be analyzed is 50% or more as the object to be analyzed, dividing the rectangular element among the two-dimensional coordinate axes A method for creating finite element data, comprising: a step of giving a node number preferentially from a small number of directions. 4. A method for creating three-dimensional finite element data of an object to be analyzed by a finite element method, comprising the steps of: setting a three-dimensional region including the object to be analyzed; Dividing the rectangular parallelepiped elements into grid elements; determining, among the rectangular parallelepiped elements, those having an area included in the analysis target object of 50% or more as the analysis target objects; and dividing the rectangular parallelepiped elements among the three-dimensional coordinate axes. A method for creating finite element data, comprising: a step of giving a node number preferentially from a small number of directions. 5. A method for creating two-dimensional finite element data of an object to be analyzed by a finite element method, comprising the steps of: setting a two-dimensional region including the object to be analyzed; Grid-dividing into rectangular elements; and, among the rectangular elements, a step in which two or more nodes of the rectangular elements are included in the object to be analyzed as an object to be analyzed. A method for creating finite element data, comprising: a step of giving a node number preferentially from a small number of directions. 6. A method for creating three-dimensional finite element data of an object to be analyzed by a finite element method, comprising the steps of: setting a three-dimensional area including the object to be analyzed; Dividing the rectangular parallelepiped elements into grid elements, and, among the rectangular parallelepiped elements, those whose nodes are included in the object to be analyzed four or more, as an object to be analyzed, and dividing the rectangular parallelepiped elements among the three-dimensional coordinate axes. A method for creating finite element data, comprising: a step of giving a node number preferentially from a small number of directions. 7. An apparatus for creating two-dimensional finite element data of an object to be analyzed by a finite element method, comprising: means for setting a two-dimensional area including the object to be analyzed; Means for grid-dividing into a plurality of rectangular elements, and, among the nodes in the specified direction of the rectangular elements, the nodes nearer to the outline among the nodes at both ends of the side through which the outline of the object to be analyzed passes. A finite element comprising: means for moving in parallel to the specified direction so as to match the contour line; and means for giving priority to the node numbers in the two-dimensional coordinate axes from the direction in which the number of divisions of the rectangular element is small. Data creation device. 8. An apparatus for creating three-dimensional finite element data of an object to be analyzed by a finite element method, comprising: means for setting a three-dimensional area including the object to be analyzed; Means for grid-dividing into a plurality of rectangular parallelepiped elements, and, in a two-dimensional cross section in a specified direction of the three-dimensional region, a side in a specified direction of a rectangular element of a cross section of the rectangular parallelepiped element, Of the nodes at both ends of the side through which the line penetrates, means for translating in the specified direction so that the node closer to the contour line coincides with the contour line, and of the three-dimensional coordinate axes, Means for preferentially assigning node numbers from the direction in which the number of divisions is small. 9. An apparatus for creating two-dimensional finite element data of an object to be analyzed by a finite element method, comprising: means for setting a two-dimensional area including the object to be analyzed; Means for dividing the rectangular element into a plurality of rectangular elements; means for regarding the rectangular element whose area included in the object to be analyzed is 50% or more as the object to be analyzed; Means for preferentially assigning node numbers from the direction in which the number of divisions is small. 10. An apparatus for creating three-dimensional finite element data of an object to be analyzed by a finite element method, comprising: means for setting a three-dimensional region including the object to be analyzed; Means for dividing the grid into a plurality of rectangular parallelepiped elements; means for considering, among the rectangular parallelepiped elements, those having an area included in the object to be analyzed of 50% or more as the object to be analyzed; Means for preferentially assigning node numbers from the direction in which the number of divisions is small. 11. An apparatus for creating two-dimensional finite element data of an object to be analyzed by a finite element method, comprising: means for setting a two-dimensional area including the object to be analyzed; Means for grid-dividing into a plurality of rectangular elements, means for considering, as the object to be analyzed, those whose nodes are included in the object to be analyzed among the rectangular elements, two or more of the two-dimensional coordinate axes Means for preferentially assigning node numbers from the direction in which the number of divisions is small. 12. An apparatus for creating three-dimensional finite element data of an object to be analyzed by a finite element method, comprising: means for setting a three-dimensional region including the object to be analyzed; Means for grid-dividing into a plurality of rectangular parallelepiped elements; means for considering, among the rectangular parallelepiped elements, four or more nodes of which are included in the object to be analyzed as the object to be analyzed; and three-dimensional coordinate axes, Means for preferentially assigning node numbers from the direction in which the number of divisions is small.