.. _R3.06.09:

**r3.06.09** Mechanical joint finite elements and hydromechanically coupled joint finite elements
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**Summary:**

This documentation relates to the description of the finite elements of linear and quadratic mechanical joints. Pure mechanical models (xxx_ JOINT) support both types of meshes, while coupled hydromechanical models (xxx_ JOINT_HYME) are only implemented for quadratic meshes. Fictional pressure degrees of freedom are eliminated for quadratic models in pure mechanics. These models make it possible to simulate the evolution of a crack along a predetermined path. The second type of element also takes into account the interaction of mechanics with a flow of fluid inside the crack.

The following points are presented in succession:


1. geometry of the elements


2. local coordinate system at the joint and matrix for the transition from the global coordinate system to the local coordinate system


3. displacement jump in the joint


4. fluid pressure gradient


5. nodal vector of internal forces as well as the elementary tangent matrix


.. toctree::
    :hidden:

    self

.. toctree::
    :maxdepth: 2
    :numbered:

    G_om_trie_des__l_ments
    Rep_re_local_et_matrice_de_passage
    Saut_de_d_placement
    Gradient_de_la_pression_de_fluide
    Efforts_int_rieurs_et_matrice_tangente
    Fonctionnalit_s_et_validation
    Description_des_versions_du_document