.. _U2.02.01:

**u2.02.01** Instructions for the use of plate, shell, grid and membrane elements
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**Summary:**

This document is a user manual for plate, shell, grid and membrane models.

Shell and plate elements are used in the numerical modeling of thin structures with an average surface, flat (plate modeling) or curved (shell modeling). Grid models are used for the numerical modeling of reinforcements and prestress cables in reinforced concrete structures. Membrane modeling makes it possible to model thin structures whose flexural stiffness is negligible.

**Mechanics**:

The DKT models are the most complete because they are capable, for thin or slightly thick structures (:math:`h/L<1/20`), of representing a wide range of linear or non-linear mechanical phenomena while remaining efficient. For problems of large transformations with constant pressure and no need to take contact into account, it is better to prefer the COQUE_3D models. If, in addition to the shell aspect and non-linear phenomena (contact, subsequent pressure), we are not interested in the flexure part (inflatable balloon for example), it is better to use the MEMBRANE models in large transformations. In the case where the structure is thick and you need to properly treat the transverse shear and the pinch, it is better to prefer the DST models in linear mechanics and to prefer the non-linear 3D model. Finally, for a geometry of revolution and with a loading remaining from revolution, it is better to prefer COQUE_AXIS in linear as in non-linear.

**Thermal**:

There are three shell models in code_aster that can deal with heat: COQUE (surface) COQUE_PLAN and COQUE_AXIS (1D).

Table of contents




.. toctree::
    :hidden:

    self

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

    Introduction
    M_canique
    Thermique
    Cha_nage_thermom_canique
    Conclusion_et_conseils_d_utilisation
    Bibliographie