1. Introduction

1.1. Choosing the type of law of behavior

The choice of the law of behavior is of course a function of the material that is being modelled, but also of the phenomena to be treated: for example, the same steel will be elasto-plastic at low temperature, and visco-plastic at high temperature.

This document gives ways to make good use of elasto- (visco) -plastic behaviors (mainly for metals).

For other types of behavior, reading the following documents is recommended:

• For laws with damage (case of concrete for example), see

  u2.05.06 u2.05.06

• For metallurgy, see

  u2.03.04

• For porous media in THM, see

  u2.04.05 and r7.01.11

• For the use of CZM elements, see

  u2.05.07 u2.05.07

• For specific laws of discrete elements, see

  r5.03.17

• For laws specific to 1D elements, see

  r5.03.09

• For hyperelastic laws (Mooney-Rivlin type) see

  r5.03.19

• For laws of behavior specific to fuel rods and metals under irradiation, see

  r5.03.08 and r5.03.23 Elasto-plastic behavior under metal irradiation: application to tank internals

• For the laws of crystalline plasticity, see

  r5.03.11 r5.03.11

1.2. Which elasto-plastic laws to choose: what are their capacities?

In this document, elements are provided for choosing laws of behavior, according to their capacities, and the phenomena to be modelled.

Advice for the identification of parameters will be given, with emphasis on the field of validity of the models: the parameters are identified for very specific deformations, speeds, temperatures, which must correspond to the studies envisaged.

On the other hand, if the models envisaged require it, it may be necessary to conduct the identifications in the field of large deformations. For this purpose, adapted formalities can be used:

• SIMO_MIEHE for Von Mises behaviors with isotropic work hardening, laws with the effect of metallurgical phases, Rousselier’s law,

• GDEF_LOG for most behaviors,

• GROT_GDEP for hyperelastic laws of the MOONEY - RIVLIN type.