Hexa20 Elements

Dear all,
is it possible, with the release of salomè incluede in pc-OsLinux 2008, make a mesh directly with elements of second order and run Code-Aster?
I think yes, because there is a specfic key to transform the mesh from first order to second, but in most example of CodeAster usage, there is the conversion of mesh from first to second order. Why?

It's very important for me, infact I usuallly transform the mesh in the salome mesh module and than I create the code aster model in the Aster module without insert the command of transformatio (I was sure that the elements were of second order!).

thanks a lot in advance.
Fabio

Hi Fabio,

I use normally second order elements in Salomè and they work good.

To be sure about that, I advise you to build a simple model with linear elements and perform an analysis; then modify elements from linear to quadratic and perform the same analysis. Finally, compare results and remark the differences.

Good luck, ciao.

Luigi

Fabio,

"there is a specfic key to transform the mesh from first order to second, but in most example of CodeAster usage, there is the conversion of mesh from first to second order. Why?"

This has a historical reason: in earlier versions of Salome and with other meshing tools used with Code-Aster there was only meshing with lin elements possible. For mechanical Analysis, the use of quadratic elements is highly recommanded in Aster. That's why there is this very nice Aster-keyword (to use in the .comm-file)

MeshQuad=CREA_MAILLAGE(MAILLAGE=MeshLin,
LINE_QUAD=_F(TOUT='OUI',),
INFO=1,);

to create a quadratic mesh from a linear one in order to analyse the quadratic one.
I like still to use this command (and after analysis the command

ResLin_2=PROJ_CHAMP(RESULTAT=ResQuad,
MODELE_1=FEMQuad,
MODELE_2=FEMLin,
NOM_CHAM=('DEPL','SIEF_NOEU_ELGA','EQUI_NOEU_SIGM',),);

to project back the results of quadratic calculation onto the linear mesh), because all files are smaller (less nodes).

Regards, Johannes