.. _R5.04.01:

**r5.04.01** Non-local modeling with gradients of internal variables GRAD_VARI
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**Summary**

Here we present the non-local gradient modeling of internal variables entitled GRAD_VARI in Code_Aster. This modeling is the result of the work of E. Lorentz [:ref:`Bib 1 <Bib 1>`]. However, the algorithm for solving the equilibrium and regularization equations has been modified compared to the initial version of the model.

Non-local models of type GRAD_VARI are available in 3D (3D_ GRAD_VARI), axisymmetric (AXIS_GRAD_VARI), and plane deformations (D_ PLAN_GRAD_VARI).

Unlike the old version, the use of GRAD_VARI is relatively simple, since it is sufficient to specify the X_ GRAD_VARI modeling in AFFE_MODELE, to specify a characteristic length under the keyword NON_LOCAL in DEFI_MATERIAU, and to check that the law of behavior that one wishes to use is indeed available in a non-local version.

The writing and numerical processing of this model are presented.




.. toctree::
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    self

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

    Rappel_sur_la_th_orie_des_mod_les___gradient
    Choix_des__l_ments_finis
    Mod_lisations_disponibles
    Lois_de_comportement_disponibles_avec_les_mod_lisations_GRAD_VARI
    Conseils_Proc_dure_pour_la_mise_en_oeuvre_d_une_nouvelle_loi_de_comportement___gradients_de_variables_internes
    Bibliographie
    Description_des_versions_du_document