J modeling
==============

Validation of the interface element HEXA8 with the cohesive law for fatigue CZM_FAT_MIX in open mode. The loading here is cyclical (see :ref:`5 <RefHeading__31154616>`) erratic. The odd times are the peaks and the even times correspond to the troughs.


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

D_ PLAN modeling for the elastic element.

Modeling PLAN_INTERFACE_S for the interface element


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

Number of knots: 12

The elastic element is a HEXA8.

The interface element is a degenerate HEXA8 (nodes combined).


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

The remark on control mentioned for modeling A also applies to this modeling.


.. csv-table::

    "**Size tested**", "**Reference**", "**Tolerance (** :math:`\text{\%}` **)**"
    "SIXXinst. 3", "6.05826", "0.10"
    "SIGN (SIEF_ELGA) inst.9", "1.45221", "0.10"
    "SIGN (DEPL) inst.9", "1.45221", "0.10"
    "SITX (SIEF_ELGA) inst.7", "0.0", "0.10"
    "V1 inst.3", "2.04959E-02", "0.10"
    "V4 inst.3", "1.94457E-01", "0.10"


**Remarks**:


* The SIXXest tested on the elastic volume element, the other tests are carried out on the interface element.


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