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#1 2016-10-11 15:55:34

bbd
Member
From: Vandoeuvre, F
Registered: 2016-09-30
Posts: 189
Website

supprimer 1D et 2D elements

bonjour
j'ai construit un maillage par extrusion dans salome-meca à l'aide du plugin gmsh
quand je clique sur maillage/information sur le maillage je constate que les éléments 1D et 2D extrudés en éléments volumiques ont été conservés.
Comment les supprimer ?
Merci d'une réponse

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#2 2016-10-11 16:06:39

bbd
Member
From: Vandoeuvre, F
Registered: 2016-09-30
Posts: 189
Website

Re: supprimer 1D et 2D elements

bon, j'ai fait un groupe de faces et un groupe d'aretes
et j'ai cliqué (bouton droit) sur supprimer groupe et son contenu.
C'est étrange mais je n'ai pas trouvé de solution plus simple.

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#3 2016-10-12 14:21:14

Johannes_ACKVA
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From: Ingenieurbüro für Mechanik, DE
Registered: 2009-11-04
Posts: 588
Website

Re: supprimer 1D et 2D elements

your idea seems plausible, but this is not the usual and practical way to work with Code-Aster.

It is very normal (in Code-Aster!) that the lower-dimensional elements (2D-skin-elements wrapping the 3D-solid-elements, 1D-edges.  Or 1D-edges arounding a mesh of plates or shells) exist and remain! They can then an any time be used to apply loads, contact conditions, boundary conditions, to limit postprocessing etc. Generally you will really need them. Example: there is no way to apply a pressure "on a face of a 3D-element" in Code-Aster (in Nastran there is this way). But you can apply the pressure only onto a 2D-element. That's why the skin elment is useful.

The "skin-element" do not disturb in any way. They do not blow up your global matrice, nor make stiffer your model. This is because in a 3D-model you do:

  Model = AFFE_MODELE(MAILLAGE=Mesh,
                      AFFE=_F(PHENOMENE='MECANIQUE',
                              TOUT='OUI',
                              MODELISATION=('3D', ),),    )

Sur les 28 mailles du maillage Mesh, on a demandé l'affectation de 28, on a pu en affecter 28
 Modélisation     Type maille  Élément fini     Nombre
                  SEG2         MECA_ARETE2      16
                  QUAD4        MECA_FACE4       10
 3D               HEXA8        MECA_HEXA8       2

You see that only your 2 HEXE8 elements get a stiffness (Modélisation 3D), the SEG2- and QUAD4-elements remain void (but exist to be used for BC etc)

You can find some more very basic information here:
http://www.code-aster.de/workflow-for-a … ation.html
or some more hints for beginners here:
http://www.code-aster.de/how-do-i-start … aster.html

Regards Johannes_ACKVA

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#4 2017-01-06 13:58:16

bbd
Member
From: Vandoeuvre, F
Registered: 2016-09-30
Posts: 189
Website

Re: supprimer 1D et 2D elements

Thks for your comment which is very helpful.
I did not used pressure input in my model but I understand that no extra stiffness was due to the 1D and 2D elements. So there was no reason to remove them.

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#5 2017-01-11 17:19:31

bbd
Member
From: Vandoeuvre, F
Registered: 2016-09-30
Posts: 189
Website

Re: supprimer 1D et 2D elements

I read in fascicule u4.51.03 OPERATOR STAT_NON_LINE :
'Caution, all the main meshes of the model
must be associated with a material (if not fatal error with not very explicit message),'

if all the meshes of the model have to be feeded with material properties, how can't they bring stiffness neither mass to the whole model?

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