Introduction
============

This document aims to guide the user in implementing a limit analysis calculation with and complements the documentation available in on limit analysis which consists of:


* reference document: [:ref:`R7.07.01 <R7.07.01>`];


* validation documents SSNV124A [:external:ref:`V6.04.124 <V6.04.124>`] and SSNV146 [:external:ref:`V6.04.124 <V6.04.124>`];


* training document: Training section of the site www.code-aster.org

To do this*code_aster* uses:



.. _OLE_LINK1:

* a regularized kinematic approach (Norton-Hoff-Friaâ regularization method, cf. [:ref:`1 <1>`]) for the Von Mises resistance criterion (adjustment by a regularization coefficient whose limit value leads to convergence);


* almost incompressible finite elements;


* a static non-linear resolution by parametric control;


* post-processing to obtain an estimate of the upper :math:`{\lambda }_{\text{lim}}^{\text{sup}}` and lower :math:`{\mathrm{\lambda }}_{\text{lim}}^{\text{inf}}` values that surround the limit value :math:`{\lambda }_{\text{lim}}`.

This document is composed of three parts:


1. the first part, which summarizes the main lines of the method and its properties;


2. the second part, which presents the various steps required to implement it in **code_aster**;


3. the third part which presents some implementation remarks based on the test case [:external:ref:`V6.04.124 <V6.04.124>`] and on the industrial case aimed at determining the limit pressure for a Canopy tank joint.