Residual stress

To determinie \"residual\" stresses, you can use either a non-linear statics analysis with an unloading step (if the source of residual stress comes from plastic/viscous strains) or a thermo-mechanical analysis (thermal induced stresses, maybe also coupled with viscous strains).

In this last case, you need to first do a non-linear thermal analysis to determine the temperature field as a function of time and re-use this field as an input for the non-linear (or linear) statics analysis: temperature field is imposed on mechanical model through the command AFFE_CHAR_MECA->TEMP_CALCULEE.

To impose initial stresses & displacements on another configuration, you can used the ETAT_INIT (=initial state) option of STAT_NON_LINE (non linear statics solver).

If the mesh is changing between two configurations, you need to project the fields on the new mesh with the command PROJ_CHAMP before you use it in the solver's initial state or in the boundary conditions definition.

Try to look for examples in the following way:
\"grep 'ETAT_INIT' /opt/aster/STA8.2/astest/*.comm\"
or with other keywords like TEMP_CALCULEE for example.

Hi,

in beta 1, you will need to first decompress the astest.tar.bz archive in /opt/aster/STA8.1/ and then do a
\"grep 'ETAT_INIT' /opt/aster/STA8.1/astest/*.comm\"

You can try to load your stress field in the following way:
- create a simple mesh containing all the coordinates of your data points (you can create rather easily an Aster \"MAIL\" mesh file with a text editor, see a .mail file for example)
- create a field: several options here.
Either you try to read a field from a MED file (LIRE_CHAMP) o r a \"result\" set from a UNV file (LIRE_RESU) or you evaluate a set of interpolated functions (CREA_CHAMP, LIRE_FONCTION)...
- then you need to project the field from the \"data\" mesh to the \"FE\" mesh with PROJ_CHAMP.

This part is a quite complex procedure, but if you can translate the document U2.01.09-A available on Code-Aster.org documentation section, there is an example on how to create an initial stress field from an analytical function. This can serve as a good base for your developments.