2. Structure of a subfile

A subfile starts with a key and ends with the imposed keyword FINSF:

This description is sufficient for*Aster*. The most complete description is as follows:

• each sub-file has 3 parts:

1. the header of the subfile,

2. the content of the information,

3. the end mark of the subfile (FINSF).

• MOTCLE and FINSF (end of subfile) are mandatory because they delimit the subfile within the mesh file.

• NOM is optional. When the keyword is GROUP_MA or GROUP_NO, if NOM is absent then the first character string encountered after this MOTS - CLES will form the NOM of the GROUP_MA or of the GROUP_NO.

By convention, any character string that follows the% character is interpreted as a comment.

2.1. The header

The role of the header is to provide global information on the content of the subfile:

MOT_CLE	In addition to its role as a subfile delitter, it provides information on the nature of the information that will follow. It should be on the first line of the subfile and framed on the left.
NOM	it is used to designate a set of information. It must be on the first line of the subfile header. It is optional.
	All other keywords are currently ignored by the operator:external LIRE_MAILLAGE.

2.2. List of information

This is information from a mailer and written in free format.

The information that this file must contain defines classical entities of the finite element method:

nodes:

points defined by a name and by their Cartesian coordinates in 2D or 3D space,

mesh:

topological figures named plane or solid (point, segment, triangle, quadrangle, tetrahedron,…), defined by the ordered list of the nodes that constitute them and to which various types of finite elements, boundary conditions or loads may be applied. The order of the knots orients the stitch. This orientation must be carefully established because it is used in particular to define the orientation of loads (pressure,…).

Groups of these topological entities can also be defined.

• node groups: named lists of node names,

• mesh groups: named lists of mesh names.

Systematically, when we have to refer to knots (or meshes), we can refer to groups of knots (or groups of meshes).

Interfaces with lessors automatically generate such groups (according to criteria specific to the lessor).

These groups make it easy to assign material characteristics to the mesh, boundary conditions, or print results. In fact, during such operations, reference is made to knots or meshes, which it is interesting to describe in groups.

The Code operator_Aster DEFI_GROUP [U4.22.01] allows you to create groups a posteriori on any mesh-type concept already read.

Note that all the entities manipulated in the code (nodes, meshes, groups of nodes, groups of meshes) are named and usable at any time by name (8 characters at most for meshes and nodes, 24 characters maximum for meshes and nodes, 24 characters maximum for GROUP_MA and GROUP_NO).

The « case » of the names is retained: for example, “ GR_AB “is different from “gr_ab”. Entity numbering is never explained: it is only used internally to point to the values of the various associated variables.

2.3. Sub-file FIN

It is the word “reserved” and mandatory FINSF that indicates the end of a subfile, which starts with a MOTCLE.