JP3216951B2 - Finite element mesh generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finite element mesh creating apparatus, and more particularly, to a method for inputting a computer program for analysis using the finite element method to two or more finite element meshes displayed on a graphic display. The present invention relates to a finite element mesh creation device for combining and creating a new finite element mesh.

[0002]

2. Description of the Related Art Conventionally, in order to create a finite element mesh of this type, first, a process of changing each finite element mesh to the same order is performed according to an instruction of a creator, and then, the same order is obtained. A process for combining a plurality of finite element meshes is performed.

[0003]

In the above-described conventional finite element mesh creation, finite element meshes of different orders cannot be combined. Therefore, when finite element meshes of different orders are combined, the order must be changed. Since the order change process is repeated for the number of necessary finite element meshes before performing the join process, the number of orders for the order change by the creator is large and the operability is poor, and the order change process and the join process are difficult. There is a problem that the processing / response time is long because the procedure is different. Further, even if the respective finite element meshes have the same order, if it is desired to change the order of the new finite element mesh after the combination, the order is changed after performing the combination. And the processing / response time becomes longer.

[0004]

According to the present invention, there is provided a finite element mesh creating apparatus for creating a new finite element mesh by combining at least two finite element meshes. A node order changing unit that changes each finite element mesh storing mesh data to a finite element mesh of a specified order and creates finite element mesh data, and a finite element that has the same order by the node order changing unit. A mesh joining unit that joins element meshes to create joined finite element mesh data, an identical coordinate node searching unit that detects nodes of the same coordinate value on the data created by the joining unit, and an identical coordinate node Element-constituting nodes that change the nodes with the same coordinate value found by the search unit to the node numbers with the lowest node numbers And the nodes changed by the element configuration node changing unit are deleted from the data, and the node numbers subsequent to the deleted node number are moved up to the smaller number of deleted node numbers to create the combined finite element mesh data. It has a node deletion / node number changing unit.

[0005]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of an embodiment of the present invention. FIG. 1 includes an input unit 1, a storage unit 2 including a disk device, a processing unit 3, and an output unit 4 including a graphic display for displaying the finite element mesh created by the processing unit 3. The input means 1 has a keyboard 11 for inputting a processing execution command and an element order after the finite element mesh is combined, a tablet 12 for specifying a finite element mesh to be combined, and a stylus pen 13. The storage means 2 stores the number of elements, the number of nodes constituting the finite element mesh, the element order, the element shape as the element data constituting the finite element mesh, the number of element constituting nodes and the node reference address, and the nodes constituting the finite element mesh. The number of nodes and the coordinates of the nodes are stored as data. The node reference address is a pointer for referring to a corresponding node record in data in which node information is stored. The processing means 3 includes a node degree changing unit 31, a mesh connecting unit 32, an identical coordinate node searching unit 33, an element configuration node changing unit 34, and a node deleting / node number changing unit 35.

[0007] The node degree changing unit 31 creates finite element mesh part information from the finite element mesh information stored in the storage means 2 and the degree after the finite element mesh specified by the keyboard 11. The mesh combining unit 32 creates one finite element mesh by combining the finite element meshes processed by the node degree changing unit 31. The same coordinate node search unit 33 searches for nodes having the same coordinates in the finite element mesh created by the mesh connection unit 32, and edits the node data. The element configuration node change unit 34 refers to the node data edited by the same coordinate node search unit 33, and if the nodes indicated by the node reference addresses of the element data have the same coordinates, considers these nodes to be the same, The node reference address of each element data is made the same. The node deletion / node number changing unit 35 deletes nodes that are no longer required due to the editing of the element data in the element configuration node changing unit 34 for the node data, and then corrects the node numbers so that there are no missing numbers. Correct the node reference address of the data.

FIG. 2 is a diagram showing the data structure of the finite element mesh stored in the storage means 2. FIG. 2A is a configuration diagram of an upper table of the finite element mesh. The first record is the total number of elements in the finite element mesh, the second record is the total number of nodes in the finite element mesh, and the third record is The order of the finite element mesh is stored. FIG. 2B is a configuration diagram of the element information table, and shows element information in the finite element mesh. The i-th record stores the element number, the element shape, the number of element constituent nodes, and the node reference address (the record number of the node information table in FIG. 2C).
In the case of a quadrilateral primary element, the node reference addresses are four items. For quadratic quadratic elements, the node reference address is 1
The reference addresses of the next nodes are stored in the first to fourth items, and the reference addresses of the secondary nodes are stored in the fifth to ninth items, for a total of nine items. If the total number of elements of the first record in the upper table of the finite element mesh is m, the number of records in the element information table is m. Also,
The node information table is a node information table in the finite element mesh, and the j-th record stores the node number of the j-th node and three-dimensional coordinate values (x, y, z). If the total number of nodes in the second record of the upper table of the finite element mesh is n, the number of records in the node information table is n.

Next, the processing of the embodiment of FIG. 1 will be described with reference to a specific example. FIG. 3 is a conceptual diagram of a finite element mesh to be combined, and FIG. 3A is a conceptual diagram of a finite element mesh composed of four finite elements (each having a quadratic primary). Here, the finite element mesh composed of the four quadrilateral primary finite elements is referred to as a finite element mesh A. FIG.
(B) is a conceptual diagram of a finite element mesh composed of two finite elements (each quadratic quadratic). Here, a finite element mesh composed of these quadratic quadratic finite elements is referred to as a finite element mesh B. The finite element mesh obtained by combining the finite element mesh A with the finite element mesh B will be referred to as a finite element mesh C. FIG. 3C is a conceptual diagram of the finite element mesh C, and shows what positions the finite element mesh A and the finite element mesh B are at the time of connection.

FIG. 4 is a diagram showing the data contents of the finite element mesh A shown in FIG. 3. FIG. 4 (a) is an upper table of the finite element mesh A, and FIG. FIG. 4C is a node information table of the finite element mesh A.

FIG. 5 is a diagram showing the data content of the finite element mesh B shown in FIG. 3, wherein FIG. 5 (a) is an upper table of the finite element mesh B, and FIG. FIG. 5C is a node information table of the finite element mesh B.

In this example, assuming that the combined degree of the finite element mesh is 1, the node degree changing unit 31
It is known that the order of the finite element mesh A is 1 from the upper table in FIG. 4A, and the process is not performed because it is the same as the order after the combination. Since the order of the finite element mesh B is known to be 2 from the upper table in FIG. 5A and is different from the order after the combination, the secondary node reference address of each record of the element information table in FIG. Is set to "0" in the node information table of FIG. That is, FIG.
The second-order node reference addresses for the element [1] are stored in the fifth to ninth items of the node reference address part of the first record of the element information table of FIG. 8, 4, and 5. Therefore, FIG.
The contents of the node number items of the second record, the sixth record, the eighth record, the fourth record, and the fifth record in the node information table (c) are set to “0”. Further, secondary node reference addresses for element [2] are stored in the fifth to ninth items of the node reference address portion of the second record of the second record of the element information table of FIG. 1
2, 14, 10, 11. Therefore, FIG.
8th record, 12th record,
The content of the item of the node number of the 14th record, the 10th record, and the 11th record is set to “0”. FIG. 6 is a diagram showing the contents of the node information table after the above-described halfway processing by the node degree changing unit 31.

Next, in the node information table shown in FIG. 6, unnecessary records are packed in ascending order of records (an unnecessary record is a record whose node number is "0"). At that time, the node number is also changed to the same value as the record number, and if there is a node reference address referring to the record of the node information table of FIG. 6 in the element information table of FIG. The address is also changed to the processed record number. After executing unnecessary record deletion processing for all records of the node information table shown in FIG. 6, the contents of the second record of the upper table shown in FIG. 5A are changed to store the total number of records in this table. I do. In order to store the order after the element order is changed, the contents of the third record of the upper table in FIG. 5A are changed. That is, first, the second node information table of FIG.
The record is an unnecessary record, and one record is packed after the third record. Next, the contents of the third record of the node information table of FIG. 6 are stored in the second record.
At this time, the node number is changed to “2”. Also, the node reference address 3 of the first record of the element information table of FIG. 5B referring to this record is changed to 2. Next, the fourth, fifth, and sixth records in the node information table in FIG. 6 are unnecessary records, and four records are packed after the seventh record. Next, the contents of the seventh record of the node information table of FIG. 6 are stored in the third record. At this time, the node number is changed to “3”. Also, the node reference address 7 of the first and second records of the element information table of FIG. 5B referring to this record is changed to 3. Next, FIG.
The eighth record of the node information table is an unnecessary record, and the ninth and subsequent records are packed with five records. Next, the contents of the ninth record of the node information table of FIG. 6 are stored in the fourth record. At this time, the node number is changed to “4”. FIG. 5 (b) referring to this record.
Change the node reference address 9 of the first and second records of the element information table to “4”. Next, the tenth, eleventh, and twelfth records in the node information table of FIG. 6 are unnecessary records, and eight records are packed after the seventh record. Next, the contents of the thirteenth record of the node information table of FIG. 6 are stored in the fifth record. At this time, the node number is changed to “5”. FIG. 5 referring to this record.
The node reference address 13 of the second record of the element information table of (b) is changed to 5. Next, the fourteenth record in the node information table of FIG.
After five records, nine records are packed. The contents of the fifteenth record of the node information table are stored in the sixth record. At this time, the node number is changed to “6”. Further, the node reference address 15 of the second record of the element information table of FIG. 5B referring to this record is changed to 6. Finally, the node information table in FIG. 6 has been deleted from nine records to six, so that the contents of the second record in the upper table in FIG. The content of the third record of the upper table in FIG. 5A is changed from 2 to 1. FIG. 7 shows the finite element mesh B after the above processing of the nodal degree change processing unit 31.
FIG. 7A shows the upper table,
FIG. 7B shows a node information table.

Next, FIG. 5 which becomes unnecessary with the order change
The fifth to ninth items of the node reference address part of the element information table of (b) are deleted. That is, the fifth to ninth items of the node reference address portion of the element information table of FIG. 5B are deleted. Then, the element information node number 9 in the element information table of FIG. FIG. 7C shows the element information table after this processing.

Next, the mesh connection unit 32 determines the upper table of the finite element mesh A shown in FIG. 4A and the upper table of the finite element mesh B shown in FIG. The upper table shown in FIG. 8A is obtained from the element information table of the finite element mesh A shown in FIG. 4B and the element information table of the finite element mesh B shown in FIG. FIG. 8 of the finite element mesh C is obtained from the node information table of the finite element mesh A shown in FIG. 4C and the node information table of the finite element mesh B shown in FIG.
A node information table shown in (b) is created. That is, the first table of the upper table of the finite element mesh C shown in FIG.
The records (total number of elements) include the contents of the first record of the upper table of the finite element mesh A shown in FIG. 4A and the contents of the first record of the upper table of the finite element mesh B shown in FIG. Is stored, that is, 6 is stored. The second record (total number of nodes) of the upper table of the finite element mesh C shown in FIG. 8A includes the contents of the second record of the upper table of the finite element mesh A shown in FIG. B is the sum of the contents of the second record of the upper table shown in FIG.
5 is stored. The third record in the upper table of the finite element mesh C shown in FIG.
4A and the same 1 as the contents of the third record of the finite element mesh B of the upper table shown in FIG. 7A. The first node information table of the finite element mesh C shown in FIG.
From the record to the ninth record, the first to ninth records of the node information table of the finite element mesh A shown in FIG. FIG. 8 of the finite element mesh C
The first record to the sixth record of the node information table of the finite element mesh B shown in FIG. 7B are copied to the tenth record to the fifteenth record of the node information table shown in FIG. At this time, only the content of the item of the node number in the node information table of the finite element mesh B shown in FIG.
The finite element mesh C of the copy destination is stored in place of the record number of the node information table shown in FIG. 8B. That is, the item contents of the finite element mesh C from the node number of the tenth record to the node number of the fifteenth record of the node information table shown in FIG.
5 ". The first to fourth records of the element information table of the finite element mesh C shown in FIG. 8C include the first record of the element information table of the finite element mesh A shown in FIG. The fifth record and the sixth record of the element information table of the finite element mesh C shown in FIG. 8C are copied to the nodes of the element information table of the finite element mesh B shown in FIG. Only the item content of the reference address has the record content of the node information table of the finite element mesh B shown in FIG. 7B, and the record number of the node information table of the finite element mesh C shown in FIG. Since the value is stored in the increased record number, the value increased by 9 is stored, that is, the node of the fifth record of the element information table of the finite element mesh C shown in FIG. Content of the item of reference address in turn 1
0, 11, 13, and 12, and the contents of the node reference address items of the sixth record are 12, 13, 15, and 14, respectively.

Next, the same-coordinate node search unit 33 executes the process shown in FIG.
In the node information table shown in (b), a search is made for records having the same coordinate value, and a search is made for those records having the smallest node number among these records. Copy to the node number item of all records That is, the seventh record and the twelfth record of the node information table shown in FIG.
0,0,0). Since the item content of the node number is "7" in the seventh record and "12" in the twelfth record, the smaller value "7" is copied as the item content of the node number in the twelfth record. The eighth record and the fourteenth record of the node information table shown in FIG. 8B have the same coordinate value (200, 100, 0). The item content of the node number is "8" in the eighth record, and "14" in the fourteenth record.
Therefore, the smaller value “8” is copied as the item content of the node number of the 14th record. FIG. 9A is a diagram showing the contents of the node information table after the above processing.

Next, the element configuration node changing unit 34
In the node information table of (a), a record whose record number is not equal to the content of the node number item of the record has the same coordinate value as the record of the record number indicated by the content of the node number item of the record. , Also the record to be deleted in the next step. Therefore, the content of the node reference address of the element information table shown in FIG. 8C referring to the record is represented by the content of the node number of the record of the node information table of FIG. 9A indicated by the node reference address. replace. That is, in the node information table of FIG. 9A, the records in which the record number is not equal to the content of the item of the node number of the record are the twelfth record and the fourteenth record. First, the twelfth record is referred to in the element information table of FIG.
The fourth item of the node reference address of the record and the first item of the node reference address of the sixth record are described. The contents of these items are represented by the node numbers of the twelfth record in the node information table of FIG. Replace with 7 for the content value of the item. Next, referring to the 14th record of the node information table of FIG. 9A is the fourth item of the node reference address of the 6th record in the element information table of FIG. 8C. Is replaced with the content value 8 of the item of the node number of the 14th record of the node information table of FIG. FIG.
(B) is a diagram showing the contents of the element information table after the above processing.

Next, the node deletion / node number changing unit 35
In the node information table of FIG. 9A, unnecessary tables are packed in ascending order of records (unnecessary records are records in which the record number and the contents of the node number items in the record are different). At this time, the node number is also changed to the same value as the record number, and if the node reference address refers to the element information table of FIG.
The content of the node reference address is similarly changed to the processed record number. After executing unnecessary record deletion processing for all records in the node information table of FIG. 9A, the total number of records in this table is stored in the second record of the upper table of FIG. 8A. That is, FIG.
The twelfth record of the node information table is an unnecessary record, and one record must be packed after the thirteenth record. Therefore, the contents of the thirteenth record of the node information table of FIG. 9A are stored in the twelfth record.
At this time, the item content of the node number is changed to “12”. Further, the contents of the node reference addresses of the fifth and sixth records in the element information table of FIG. 9B referencing this record are changed to “12”. The 14th record of the node information table in FIG. 9A is an unnecessary record, and the 15th record and the subsequent records are two records. Therefore, the contents of the fifteenth record of the node information table of FIG. 9A are stored in the thirteenth record. At this time, the item content of the node number is changed to “13”. Further, the content of the reference address of the sixth record in the element information table of FIG. 9B referring to this record is changed to 13.
Then, 13 as the total number of nodes is stored in the second record of the upper table of FIG. FIG. 10 (a), FIG.
(B) and FIG. 10 (c) are diagrams showing the contents of the upper table, the node information table, and the element information table of the finite element mesh C after the above processing, respectively, and FIG. It is a conceptual diagram.

[0019]

As described above, according to the present invention, when a plurality of finite element meshes are combined, the finite element meshes have the same degree changing function, so that finite element meshes of different orders are combined. When changing the order of the finite element mesh after joining, it is possible to create a new finite element mesh in a single procedure, reduce the number of instructions by the creator, improve operability, improve processing and response time There is an effect that it can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a format of data content of a finite element mesh stored in a storage unit of the embodiment of FIG.

FIG. 3 is a conceptual diagram showing an example of a finite element mesh to be combined for explaining the embodiment of FIG. 1;

FIG. 4 is a diagram showing data contents of a finite element mesh A in the conceptual diagram of FIG. 3;

FIG. 5 is a diagram showing data contents of a finite element mesh B in the conceptual diagram of FIG. 3;

FIG. 6 is a diagram showing an example of the contents of a node information table in the process of being processed by a node degree changing unit in the embodiment of FIG. 1;

FIG. 7 is a diagram showing data contents of a finite element mesh B after processing by a node degree changing unit of the embodiment of FIG. 1;

FIG. 8 is a diagram showing data contents of a finite element mesh C after processing by the mesh connection unit of the embodiment of FIG. 1;

9 shows the contents of the node information table of the finite element mesh C after processing by the same coordinate node search unit and the element information table of the finite element mesh C after processing by the element configuration node changing unit in the embodiment of FIG. 1; FIG.

FIG. 10 is a diagram showing data contents of a finite mesh C after processing by a node deletion / node number changing unit of the embodiment of FIG. 1;

11 is a conceptual diagram of a finite mesh C after processing by a node deletion / node number change unit in the embodiment of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input means 2 Storage means 3 Processing means 4 Output means 11 Keyboard 12 Tablet 13 Stylus pen 31 Nodal degree change part 32 Mesh connection part 33 Same coordinate node search part 34 Element configuration node change part 35 Node deletion / node number change part

Claims (1)

(57) [Claims] 1. A finite element mesh creating apparatus for creating a new finite element mesh by combining at least two finite element meshes, wherein each finite element mesh whose finite element mesh data is stored in a storage means is designated. A node order change unit that changes the finite element mesh of the given order to create finite element mesh data and a finite element mesh that has the same order by the node order change unit are combined, and the combined finite element mesh data is A mesh connection unit to be created, a same coordinate node search unit that detects nodes having the same coordinate value on the data created by the connection unit, and a node having the same coordinate value searched by the same coordinate node search unit. An element configuration node change unit that changes to the node number with the lowest node number, and a node changed by this element configuration node change unit Having a node deletion / node number change unit for creating data of a finite element mesh which is deleted by deleting the point from the data and raised to a smaller number after deleting the node number after the deleted node number and joined. Finite element mesh generator.