Meaning of internal variables
====================================

The internal variables of the model at the Gauss points (VARI_ELGA) are for all models:


* VARI_1 = :math:`\text{p}`: the cumulative plastic deformation (positive or zero)


* VARI_2 = :math:`\xi`: equal to 1 if the Gauss point has plasticized during the increment or 0 otherwise.

:math:`\text{X}`: reminder tensor:

For 3D modeling:


* VARI_3 = :math:`{X}_{\text{11}}`


* VARI_4 = :math:`{X}_{\text{22}}`


* VARI_5 = :math:`{X}_{\text{33}}`


* VARI_6 = :math:`{X}_{\text{12}}`


* VARI_7 = :math:`{X}_{\text{13}}`


* VARI_8 = :math:`{X}_{\text{23}}`

For D_ PLAN, C_ PLAN, AXIS models


* VARI_3 = :math:`{X}_{\text{11}}`


* VARI_4 = :math:`{X}_{\text{22}}`


* VARI_5 = :math:`{X}_{\text{33}}`


* VARI_6 = :math:`{X}_{\text{12}}`

For shell models (DKT, COQUE_3D), in a local coordinate system and at each integration point of each layer:


* VARI_3 = :math:`{X}_{\text{11}}`


* VARI_4 = :math:`{X}_{\text{22}}`


* VARI_5 = :math:`{X}_{\text{33}}`


* VARI_6 = :math:`{X}_{\text{12}}`