====== Isotropic hardening ======

The ''IsotropicHardening'' class manages all isotropic hardening laws in Metafor. The laws developed for thixotropic materials are are described below.


===== ShimaOyaneIsotropicHardening =====

=== Description ===

Isotropic hardening, specific for thixotropic materials. Shima and Oyane extended laws, only taking one internal parameter into account, the [doc:user:elements:volumes:thixo_scheilliquidfractionmatlaw|liquid fraction]], either full ($ f_l $ if SSIH_EFF = 0) or effective: ($ f_l^{eff} if SSIH_EFF = 1) . 

$$
\sigma_{vm} = \sigma_{vm}^{sol} (1-f_l)^{h_2}
$$

where $$ \sigma_{vm}^{sol} $$ is the yield stress for the solid phase, computed using any isotropic hardening law.

=== Parameters === 
^          Name                                         ^  Metafor Code^ Dependency ^
|Number of the isotropic hardening law              |  ''SSIH_NUM''  |  ''TM/TO''         |
|Shima et Oyane parameter $h_2 $                    |   ''SSIH_H2''  |  ''TM/TO''         | 
|Use of full or effective liquid fraction           |   ''SSIH_EFF''  |  '' / ''         | 

:!: Careful: Only works if used with thixotropic materials (''ThixoEvpIsoHHypoMaterial'' or  ''ThixoTmEvpIsoHHypoMaterial'').