====== Fields at Gauss Points ======

Fields that are computed at each integration point are referenced by codes with the ''IF'' prefix (standing for **I**nternal **F**ield).


^  Metafor Code  ^  Description  ^
| ''IF_DEV_SIG_XX'' | Cauchy stress deviator tensor (see important remark at the bottom) |
| ''IF_DEV_SIG_YY'' |  :::|
| ''IF_DEV_SIG_ZZ'' |  :::|
| ''IF_SIG_XX'' | Cauchy stress tensor (see important remark at the bottom) |
| ''IF_SIG_YY'' |  :::|
| ''IF_SIG_ZZ'' |  :::|
| ''IF_SIG_XY'' |  :::|
| ''IF_SIG_XZ'' |  :::|
| ''IF_SIG_YZ'' |  :::|
| ''IF_SIG_1'' | Cauchy Principal stress 1 |
| ''IF_SIG_2'' | Cauchy Principal stress 2 |
| ''IF_SIG_3'' | Cauchy Principal stress 3 |
| ''IF_DEV_SIG_ORTHO_XX'' | Cauchy stress deviator tensor in a frame which moves with the matter (see important remark at the bottom) |
| ''IF_DEV_SIG_ORTHO_YY'' | :::|
| ''IF_DEV_SIG_ORTHO_ZZ'' | :::|
| ''IF_SIG_ORTHO_XX'' | Cauchy stress deviator tensor in a frame which moves with the matter|
| ''IF_SIG_ORTHO_YY'' |:::   |
| ''IF_SIG_ORTHO_ZZ'' |:::   |
| ''IF_SIG_ORTHO_XY'' |:::  |
| ''IF_SIG_ORTHO_XZ'' |:::  |
| ''IF_SIG_ORTHO_YZ'' |:::  |
| ''IF_ALP_XX'' | "backstress" (kinematic hardening) |
| ''IF_ALP_YY'' |  :::|
| ''IF_ALP_ZZ'' |  :::| 
| ''IF_ALP_XY'' |  :::| 
| ''IF_ALP_XZ'' |  :::|
| ''IF_ALP_YZ'' |  :::|
| ''IF_GL_STRAIN_XX'' | Green-Lagrange strains (in the initial frame) |
| ''IF_GL_STRAIN_YY'' |  :::|  
| ''IF_GL_STRAIN_ZZ'' |  :::|  
| ''IF_GL_STRAIN_XY'' |  :::|  
| ''IF_GL_STRAIN_XZ'' |  :::|  
| ''IF_GL_STRAIN_YZ'' |  :::| 
| ''IF_NAT_STRAIN_XX'' | Natural strains (in the initial frame) |
| ''IF_NAT_STRAIN_YY'' |  :::| 
| ''IF_NAT_STRAIN_ZZ'' |  :::|  
| ''IF_NAT_STRAIN_XY'' |  :::| 
| ''IF_NAT_STRAIN_XZ'' |  :::|  
| ''IF_NAT_STRAIN_YZ'' |  :::| 
| ''IF_BIOT_STRAIN_XX'' | Biot strains (in the initial frame)|
| ''IF_BIOT_STRAIN_YY'' |  :::|  
| ''IF_BIOT_STRAIN_ZZ'' |  :::|  
| ''IF_BIOT_STRAIN_XY'' |  :::|  
| ''IF_BIOT_STRAIN_XZ'' |  :::|  
| ''IF_BIOT_STRAIN_YZ'' |  :::| 
| ''IF_ALP_J2'' | contrainte cinématique équivalente :?: | 
| ''IF_P'' | pressure | 
| ''IF_EPL'' | equivalent plastic strain | 
| ''IF_DEPL'' | equivalent plastic strain rate | 
| ''IF_EVMS'' | von Mises stress | 
| ''IF_CRITERION'' | Plastic Criterion (different to EVMS if VonMises is not used as plastic Critetion) | 
| ''IF_YIELD_STRESS'' | yield stress | 
| ''IF_VISCOPLAST_STRESS'' | Visco-Plastic Stress | 
| ''IF_GRAINSIZE'' | grain size Value | 
| ''IF_GRAINSIZE_STRESS'' | grain size Stress | 
| ''IF_TRIAX'' | stress triaxiality T = hydrostatic stress / equivalent stress | 
| ''IF_RUPT_CRIT'' | rupture Criterion |
| ''IF_ISO_DAMAGE'' | isotropic damage | 
| ''IF_DAMAGE_XX'' | orthotropic damage |
| ''IF_DAMAGE_YY'' |   :::|
| ''IF_DAMAGE_ZZ'' |   :::|
| ''IF_DAMAGE_XY'' |   :::|
| ''IF_DAMAGE_YZ'' |   :::|
| ''IF_DAMAGE_XZ'' |   :::|
| ''IF_RHO'' | density | 
| ''IF_FLUX_X'' | heat flux | 
| ''IF_FLUX_Y'' |  :::| 
| ''IF_FLUX_Z'' |  :::| 
| ''IF_GRADT_X'' | temperature gradient | 
| ''IF_GRADT_Y'' |  :::| 
| ''IF_GRADT_Z''  |  :::| 
| ''IF_DEV_SIG_XX_UPPER_SIDE'' | stress deviator tensor - upper skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} |
| ''IF_DEV_SIG_YY_UPPER_SIDE'' |  :::|
| ''IF_DEV_SIG_ZZ_UPPER_SIDE'' |  :::|
| ''IF_SIG_XX_UPPER_SIDE'' | stress tensor - upper skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} |
| ''IF_SIG_YY_UPPER_SIDE'' |  :::|
| ''IF_SIG_ZZ_UPPER_SIDE'' |  :::|
| ''IF_SIG_XY_UPPER_SIDE'' |  :::|
| ''IF_SIG_XZ_UPPER_SIDE'' |  :::|
| ''IF_SIG_YZ_UPPER_SIDE'' |  :::|
| ''IF_P_UPPER_SIDE'' | pressure - upper skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} | 
| ''IF_EPL_UPPER_SIDE'' | equivalent plastic strain - upper skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} | 
| ''IF_DEV_SIG_XX_LOWER_SIDE'' | stress deviator tensor - lower skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}}  |
| ''IF_DEV_SIG_YY_LOWER_SIDE'' |  :::|
| ''IF_DEV_SIG_ZZ_LOWER_SIDE'' |  :::|
| ''IF_SIG_XX_LOWER_SIDE'' | stress tensor - lower skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} |
| ''IF_SIG_YY_LOWER_SIDE'' |  :::|
| ''IF_SIG_ZZ_LOWER_SIDE'' |  :::|
| ''IF_SIG_XY_LOWER_SIDE'' |  :::|
| ''IF_SIG_XZ_LOWER_SIDE'' |  :::|
| ''IF_SIG_YZ_LOWER_SIDE'' |  :::|
| ''IF_P_LOWER_SIDE'' | pressure - lower skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} | 
| ''IF_EPL_LOWER_SIDE'' | equivalent plastic strain - lower skin of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} | 
| ''IF_THICKNESS'' | deformed thickness of a shell{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} |
| ''IF_CURVATURE_XX'' | shell curvatures{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} |
| ''IF_CURVATURE_YY'' |  :::|
| ''IF_CURVATURE_ZZ'' |  :::|
| ''IF_CURVATURE_XY'' |  :::|
| ''IF_CURVATURE_XZ'' |  :::|
| ''IF_CURVATURE_YZ'' |  :::|
| ''IF_TORQUE_XX'' | shell torques{{:doc:user:ico-expert.png?18|Expert!}}{{:doc:user:ico-danger.png?18|Danger!}} |
| ''IF_TORQUE_YY'' |  :::|
| ''IF_TORQUE_ZZ'' |  :::|
| ''IF_TORQUE_XY'' |  :::|
| ''IF_TORQUE_XZ'' |  :::|
| ''IF_TORQUE_YZ'' |  :::|
| ''IF_FTOTAL_XX'' | deformation gradient |
| ''IF_FTOTAL_YY'' |  :::|
| ''IF_FTOTAL_ZZ'' |  :::|
| ''IF_FTOTAL_XY'' |  :::|
| ''IF_FTOTAL_XZ'' |  :::|
| ''IF_FTOTAL_YZ'' |  :::|
| ''IF_FTOTAL_YX'' |  :::|
| ''IF_FTOTAL_ZX'' |  :::|
| ''IF_FTOTAL_ZY'' |  :::|
| ''IF_LODE_PARAMETER'' | Lode parameter $\in [-1,1]$ |

This codes are to be used in [[doc:user:results:courbes_res]] to specify which field must be archived. 

Important note: ''IF_SIG_XX'' stresses are always Cauchy stresses, whether a [[doc:user:elements:volumes:iso_hypo_materials#evpisohhypomaterial|hypoelastic]] or [[doc:user:elements:volumes:hyper_materials#neohookeanhyperpk2material|hyperelastic]] formulation is used. To get Piola-Kirchhoff-2 stresses, the transformation formula must be applied, used the gradient deformation tensor (''IF_FTOTAL_XX'', ...):

$$
 \boldsymbol{\sigma}_{\text{cauchy}} = \dfrac{\mathbf{F}\,\boldsymbol{\sigma}_{\text{PK2}}\,\mathbf{F}^T}{\det(\mathbf{F}_{\text{total}})}
$$