wiki:public/doc/by_ext/msh/S_elements
Last modified 3 years ago Last modified on 08/05/15 09:47:41

Description

The $ELEMENTS keyword introduces the topological definition of element types and their conncetivity.

Parameters

  • Number of elements: At first the number of all elements must be given in the subsequent line under the subkeyword $ELEMENTS.
  • List of elements: int int char int int int int int int int int The 1st parameter (int) defines the element index. The numbering starts always with "0" and must be complete and without gaps. The 2nd parameter (int) assignes a material number to the element. Therefore, the element is directly linked with the material properites given in the MMP file. Again we start counting from zero, i.e. "0" is linked with the first material property definition of the MMP file. The 3rd parameter (char) defines the element type. OpenGeoSys supports the following element type keywords:

line (Line) tri (Triangle) quad (Rectangle) tet (Tetrahedra) pris (Prism) hex (Hexahedra)

The parameters after the element type definition (int int . . .) are the node indezes forming the element. According to the element type, 2.3.4.6 or 8 numbers must be given. See examples below.

Examples:

  0 0 line 321 60
  1 4 tri 58 328 59
  2 5 quad 304 1 351 17
  3 2 tet 339 294 337 219
  4 1 pris 328 311 297 54 53 307
  5 3 hex 344 314 343 28 319 29 307 316

Order of nodes

hex:
    4. . . . . . . . . . 3
  / |                 /  |
1. . . . . . . . .  2    |
|   |               |    |
|   |               |    |
|   8  . . . . . .  | . 7
| /                 | /
5. . . . . . . . . .6

prism:
       3
    / |  \
  /   |    \   
1 . . . . . 2
|     |      |
|     6      |
|   /|  \   |
| /  |    \ | 
4 . . . . . 5

pyra
     '          5
              /=\\
             /===\ \
            /=====\' \
           /=======\'' \
          /=========\ ' '\
         /===========\''   \
        /=============\ ' '  \
       /===============\   ''  \
      /=================\' ' ' ' \
     /===================\' ' '  ' \
    /=====================\' '   ' ' \
   /=========4=============\  '   ' 3
  /=========================\   ' /
 /===========================\'  /
1=============================2

Examples

1

#FEM_MSH
 $NODES
 7500
0 0.0 0.0 0.0
1 1000.0 0.0 0.0
2 1000.0 750.0 0.0
3 0.0 750.0 0.0
4 10.10101010 750.0 0.0
5 20.20202020 750.0 0.0
: : : :
: : : :
: : : :
 $ELEMENTS
7326
0 0 quad 3 4 346 345
1 0 quad 345 346 347 344
2 0 quad 344 347 348 343
3 0 quad 343 348 349 342
: : : :
: : : :
: : : :
#STOP