.. _r5.03.08:

**r5.03.08** Integration of viscoelastoplastic behavior relationships in nonlinear mechanical operators
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**Summary**

This document describes, in the case of nonlinear viscoelastic and viscoelastoplastic behaviors with threshold, built on the basis of Lemaître's nonlinear viscoelastic model, the ingredients necessary for the implementation of the nonlinear mechanics algorithm, as in STAT_NON_LINE described in [:ref:`R5.03.01 <R5.03.01>`]. The input data for all of these nonlinear viscoelastic behavior relationships embedded in *Code_Aster* generally have the same shape. Only the way to enter the main data (the viscous deformation rate function) varies: it is presented according to the various keywords that allow the user to choose the desired behavior relationship.

These quantities are calculated by a semi-implicit or implicit integration method. From the initial state, or from the previous calculation instant, the stress field resulting from a deformation increment is calculated.




.. toctree::
    :hidden:

    self

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

    Introduction
    Relation_continue
    Nature_de_la_fonction_g_pour_chacune_des_relations_de_comportement
    Int_gration_de_la_relation_de_comportement
    Calcul_de_l_op_rateur_tangent
    Bibliographie
    Description_des_versions_du_document