3. Operands#

3.1. Operand MODELE#

♦ MODELE = me,

Model name X- FEM generated by the MODI_MODELE_XFEM command.

3.2. Operands PREF_NOEUD_X, PREF_NOEUD_M, PREF_NOEUD_P, PREF_MAILLE_X, PREF_GROUP_CO#

♦ PREF_NOEUD_X = pref_nx,

♦ PREF_NOEUD_M = pref_nm,

♦ PREF_NOEUD_P = pref_lp,

♦ PREF_MAILLE_X = pref_mx,

♦ PREF_GROUP_CO = pref_gc,

pref_nx: prefix for the name of the new simple nodes (not located on the lips).

pref_nm: prefix for the name of the new double nodes located on the "minus" lip.

pref_nm: prefix for the name of the new double nodes located on the "plus" lip.

pref_mx: prefix for the name of the new meshes.

pref_gc: name of the group created with the nodes located on the "minus" lip.


The names by default can cause errors if these names already exist in the initial mesh (which can be the case with a mesh from Salome, because Salome does not name the nodes :math:`\mathrm{N1}`, :math:`\mathrm{N2}`...).


The group of nodes PREF_GROUP_CO is intended to be used for contact post-processing. It contains exactly the nodes on the slave side of the crack that will carry contact ddls (after calling POST_CHAM_XFEM).

3.3. notes#

  1. The concept produced by this command is only for post-processing X- FEM elements. Under no circumstances should it be used for the calculation.

  1. To allow the crack to open, the top nodes of the initial mesh belonging to the crack were doubled and new nodes of the crack plane were added to perform the sub-cutting of the X-FEM cells.

  1. The GROUP_MA groups of the healthy mesh are retained in the post-processed mesh:

  • if a GROUP_MA mesh is classic, it is copied as it is in the GROUP_MA of the post-processed mesh,

  • if a GROUP_MA mesh is X- FEM, it is replaced by its sub-elements in the GROUP_MA of the post-processed mesh, provided that the mesh is properly assigned to a model.

It is therefore possible that some GROUP_MA disappear, if they only contain meshes without modeling.

  1. To allow the visualization of crack bottoms, knots and meshes are constructed at these points. The prefix for constructed nodes is \(\mathit{NF}\) and the prefix for stitches is \(\mathit{MF}\). The meshes are POI1 in 2D and SEG2 in 3D.

Clusters of knots and meshes are also constructed. The groups of nodes are named \(\text{NF\_xx\_yy}\) where \(\mathit{xx}\) refers to the \(\mathit{xx}\) th crack and \(\mathit{yy}\) refers to the \(\mathit{yy}\) th bottom. The mesh groups are named \(\text{MF\_xx\_yy}\) or \(\mathit{xx}\) refers to the \(\mathit{xx}\) th crack and \(\mathit{yy}\) refers to the \(\mathit{yy}\) th bottom.