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## #1 2012-03-23 23:20:05

Theobalt
Member
Registered: 2009-03-11
Posts: 119

### Easy question: how to set a force on a surface?

Hi!

From what I understand FORCE_FACE requires a force per unit area. Is there a way to say to Code_aster to set a let's say 1000N force on such or such area, or do I have to manually compute the area of the given surface, compute the resulting force per unit area and then enter that value at the FORCE_FACE keyword?

In short, with Abaqus, Cosmos, and others, we simply indicate for example: "put 1000N on the surface A." Is there an equivalent with Code_Aster?

Thanks!

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## #2 2012-03-24 14:53:01

Johannes_ACKVA
Member
From: Ingenieurbüro für Mechanik, DE
Registered: 2009-11-04
Posts: 595
Website

### Re: Easy question: how to set a force on a surface?

Theobald,
there is no "put 1000N on the surface A."  in Code-Aster. But it is not necessary to compute You surface manually. You can insert the POST_ELEM command in order to get and then print the surface area of the whole mesh or of a group of elements. Example:

MeshLin=LIRE_MAILLAGE();

dkt=AFFE_MODELE(MAILLAGE=MeshLin,
VERIF='MAILLE',
AFFE=_F(TOUT='OUI',
PHENOMENE='MECANIQUE',
MODELISATION='DKT',),);

elastic=DEFI_MATERIAU(ELAS=_F(E=200000.0, RHO=1, NU=0.0,),);

Mat=AFFE_MATERIAU(MAILLAGE=MeshLin, AFFE=_F(TOUT='OUI', MATER=elastic,),);

Cara=AFFE_CARA_ELEM(MODELE=dkt,
COQUE=_F(GROUP_MA='PLATE_T1',EPAIS=1.0,),);

tab_post=POST_ELEM(MASS_INER=_F(GROUP_MA='PLATE_T1'),
MODELE=dkt,
CHAM_MATER=Mat,
CARA_ELEM=Cara,
TITRE='tit_von_post_elem',);
IMPR_TABLE(TABLE=tab_post,);

After read the surface area You can commentarize the POST_ELEM and IMPR_TABLE command and add the subsequent commands editing the load in AFFE_CHAR_MECA.

If You need more automatization You can extract the surface area from table tab_post using python commands and calculate using python the load value to input, but I think the first way is quite easy and sufficient.

Johannes Ackva
______________________________________________________________________
Ingenieurbüro für Mechanik
Dr.-Ing. Johannes Ackva
Markgrafenstr. 21
D 91717 Wassertrüdingen

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Last edited by Johannes_ACKVA (2012-03-24 14:53:34)

Ingenieurbüro für Mechanik
D 91717 Wassertrüdingen / Germany

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