N modeling
==============

Validation of the interface element HEXA20 with the cohesive law for fatigue CZM_TRA_MIX in open mode. Loading here is cyclical to cycle through all states of the law.


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

3D modeling for the elastic element.

3D modeling_ INTERFACE_S for the interface element


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

Number of knots: 32

The elastic element is a HEXA20.

The interface element is a degenerate HEXA20 (nodes combined).


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

The quantities tested and the results are identical to those obtained in :math:`\mathrm{2D}` (see modeling :math:`M`).


.. csv-table::

    "**Size tested**", "**Reference**", "**Tolerance (** :math:`\text{\%}` **)**"
    "SIGN (SIEF_ELGA) inst.9", "9", "0.10"
    "SIGN (DEPL) inst.9", "9", "0.10"
    "SITY inst.9.6", "0.0", "0.10"
    "V1 installation 2.5 (contact)", "0.01", "0.10"
    "V4 installation 2.5 (contact)", "0", "0.10"


.. csv-table::

    "V1 inst.5.4 (tray)", "0.017991", "0.10"
    "V4 inst. 5.4 (tray)", "0.079910", "0.10"


.. csv-table::

    "V1 inst.7.4 (discharge)", "0.029991", "0.10"
    "V4 inst. 7.4 (discharge)", "0.199910", "0.10"
    "V1 inst.12.6 (endo)", "0.108662", "0.10"
    "V4 inst.12.6 (endo)", "0.869312", "0.10"
    "V1 inst.23 (broken)", "0.16", "0.10"
    "V4 inst.23 (breaking)", "1", "0.10"


We test the normal stress on a gauss point: SIGN (SIEF_ELGA) as well as the Lagrange multiplier on a middle node: SIGN (DEPL).

Unlike :math:`\mathrm{2D}`, we're testing SITY instead of SITX