elty

  'elty' <set> 'be2'|'be2r'|'be2f'|'be2d'|->
'be3'|'be3r'|'be3f'|->
'tr3'|'tr3u'|'tr3e'|'tr3s'|'tr3c'->
'tr6'|'tr6u'|'tr6e'|'tr6s'|'tr6c'|->
'qu4'|'qu4e'|'qu4s'|'qu4c'|->
'qu4r'|'qu4er'|'qu4sr'|'qu4cr'|->
'qu8'|'qu8e'|'qu8s'|'qu8c'|->
'qu8r'|'qu8er'|'qu8sr'|'qu8cr'|->
'he8'|'he8f'|'he8i'|'he8r'|->
'he20'|'he20r'|'pe6'|'pe6f'|'pe15'|->
'pe15r'|'te4'|'te4f'|'te10'|'te10m'|->
'te10t' [<parameter>]

This keyword is used to assign a specific element type to a set of entities (see section Element Types in the appendix). In most cases it can be used to specify the element type before the mesh is created. In case of unstructured meshes the element attributes have to be assigned after the mesh is created (from tr6u to tr6c or te10 to te10t etc.).

The element name is composed of the following parts: The leading two letters define the shape (be: beam, tr: triangle, qu: quadrangle, he: hexahedra, pe: penta, te:tetraeder), then the number of nodes and at last an attribute describing the mathematical formulation or other features (c: axisymmetric, e: plain strain, s: plain stress, u: unstructured mesh, r: reduced integration, i: incompatible modes, f: fluid element for ccx, t: initial temperatures are interpolated linearly within the tet element (ccx:C3D10T)).

If the element type is omitted, the assignment is deleted. If all parameters are omitted, the actual assignments are posted:

elty

will print only the sets with assigned elements. Multiple definitions are possible. For example,

elty all

deletes all element definitions. If the geometry was already meshed, the mesh will NOT be deleted. If the mesh command is executed again after new assignments has taken place, additional elements will be created.

elty all he20

assigns 20 node brick-elements to all bodies in the set all.

elty part1 he8

redefines that definition for all bodies in the set part1.

elty part2 tr6u

assigns 6 node unstructured triangle elements to all surfaces in set part2.

elty part2 tr6u 0.5

will do the same but specifies a mesh refinement factor of 0.5 (>1: coarser than the average boundary spacing, <1: denser ). Be aware that specialized unstructured meshes must be created by using two times the elty command. First time the general unstructured type before the mesh is actually created and afterwards a redefinition into the more specific type:

elty part2 tr6u
mesh all
elty part2 tr6c

creates an axisymmetric unstructured mesh.

elty part3 te10

assigns 10 node elements to all bodies in set part3. But this works only if NETGEN [4] is installed and the program ng_vol is accessible.

elty part3 te10 3.5

will do the same but specifies a target size for the elements. In this case the modified program ng_vol from the cgx-distribution must be available. Replace the original ng_vol in the NETGEN package and build it again. Be aware that specialized unstructured meshes must be created by using two times the elty command. First time the general unstructured type before the mesh is actually created and afterwards a redefinition into the more specific type:

elty part2 te10
mesh all
elty part2 te10t

The penta element types are not supported for meshing but can be used to redefine the attributes (pe6 to pe6f). Penta elements are only created if a mesh of triangles (2D) is sweeped in 3D. This procedure is used to create quasi 2D cfd meshes.

The fluid network element types are be2f and be3f. The be2f has to be used at the begin and the end of a network. This elements will use the special node nr '0' at the entry and exit. This node-nr is automatically assigned to the element definition when written in the ccx format. All other elements in the network must use the be3f type. The detailed element type definition has to be done in the ccx input file based on element-sets.