.. _U2.04.04:

**u2.04.04** Instructions for using contact in code_aster
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**Summary:**

This document describes the procedure to be followed for taking into account contact and friction conditions in nonlinear studies. We are interested in surface contact between deformable solids or between a deformable solid and a rigid solid. First, we recall what it means to take into account touch-friction in structural mechanics, then we draw the main lines of a contact problem in code_aster: matching and resolution.

The contact is defined with the DEFI_CONTACT command while the resolution is done with the STAT_NON_LINE or DYNA_NON_LINE commands. Recommendations are formulated for the parametrization of the pairing and the choice of resolution methods in these operators.

Finally, various methodologies are mentioned (contact with a rigid surface, recovering contact pressure during post-treatment, large deformations and contact, rigid body movements blocked by contact,...). They make it possible to overcome the difficulties frequently encountered in studies. In this section, alternative models of the phenomenon of touch-friction by joint elements or discrete elements (through the law of behavior) are also discussed.

**Table of Contents**




.. toctree::
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    self

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

    Introduction
    Appariement
    R_solution
    M_thodologies
    Bibliographie