Modeling A
==============


Characteristics of modeling
-----------------------------------

The **simplex** method is used by PROPA_FISS.


Characteristics of the mesh
----------------------------

The structure is modelled by a mesh composed of 2040 elements HEXA8 (see).


.. image:: images/100002010000013B000003381CEECC25E0FB087B.png
    :width: 1.2591in
    :height: 3.2929in


.. _RefImage_100002010000013B000003381CEECC25E0FB087B.png:

Figure 3.2-a: structure mesh

The mesh is very coarse to reduce the calculation time. Slightly smaller elements are used in the crack propagation zone. The dimension of the elements is :math:`0.17\times 0.33\times 0.2m` in this area. The largest element used has a dimension equal to :math:`0.17\times 0.8\times 1.6m`.


Tested sizes and results
------------------------------

We extract the normal (:math:`\mathrm{LSN}`) and tangent (:math:`\mathrm{LST}`) level set using the POST_RELEVE_T operator using the operator and we check that the maximum and minimum values remain within the radius of capture of the nodes tested around the crack front, i.e. 1/3:


.. csv-table::

    ":math:`\mathrm{Propag.}i` "," :math:`\mathrm{Max}{\mathrm{LSN}}_{i}` "," :math:`\mathrm{Min}{\mathrm{LSN}}_{i}` "," "," :math:`\mathrm{Max}{\mathrm{LST}}_{i}` "," :math:`\mathrm{Min}{\mathrm{LST}}_{i}`"
    "3", "0.2", "0.2", "0.2", "0.267", "0.267"


The results obtained clearly show that the level-sets remain less than the radius in which the crack front was located. This means that the crack bottom has been correctly located by the simplex method.