5. Link assignment X- FEM

This is the treatment of the keyword “LIAISON_XFEM” in “AFFE_CHAR_MECA”, specific for X- FEM, and no change has occurred for the transition to contact in major landslides. We briefly present the Fortran routines by specifying that the main purpose is to apply relationships between contact degrees of freedom to satisfy condition LBB. The treatment also serves to eliminate excess degrees of contact freedom in the case of the old formulation.

Here is an example of a call in the command file:

CHXFEM = AFFE_CHAR_MECA (MODELE = MODELEK,

CONTACT_XFEM = CTXFEM,

LIAISON_XFEM =” OUI “,);

The description of Fortran routines and their call tree (Figure 4) are given below.

CAXFEM — the launch routine for operations to cancel excess contact degrees of freedom.

XDELCO - routine to remove excess contact degrees of freedom. Only for the old formulation of contact, where the Lagrangians are stored at the edges.

XRELCO — routine for applying relationships between contact degrees of freedom in order to satisfy condition LBB. Remember that these relationships are now created in the operator DEFI_CONTACT (FORMULATION =” XFEM “). Regarding the respect of condition LBB for large landslides, it turns out that the algorithms developed and implemented for the HPP [8] case work well in this case, which is logical considering that the contact unknowns are stored only on the slave part of the crack.

AFLRCH — the routine that assigns the relationship list to the load object. In other words, this routine makes it effective to apply the list of relationships created previously.

Figure 4. The AFFE_CHAR_MECA operator call tree, LIAISON_XFEM keyword