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2 quick doubts

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2 quick doubts

Posted by npmc at November 06. 2012

Hello,

I'm a newcomer here and I've been using Salome fora couple weeks (noobie phase).

I've got these "little" doubts that experienced people can quickly dissolve:

- Is there a Mesh algorithm more used/recommended to complex 3D shape structures?

      I've been using 3D Tetrahedron (Netgen) and NetGen 1D-2D because meshing with Hexaedron's and 3D extrusion doesn't seem very adequate/easy. 

 

- I've been trying the LIAISON_MAIL "command". Is it recommended to be used when we want to "mate" different meshes (like Mesh_1 and Mesh_2), or it can also be used like in the Press example (by  cacciatorino) were there is only one Mesh? 

     Is there another way to assign the connections between parts in the Salome in order to the code-aster run it? (making Fuse between the parts leads to not accurate physics i guess.)

 

Best regard's.

Re: 2 quick doubts

Posted by Cacciatorino at November 07. 2012

About the first question, I don't have an answer.

 

About the second:

Let's think to a 3d-model (but it is the same for a 2d-problem of course): You have two meshes _1 and _2and you are looking for a way to connect them, so they can interact onew with the other. There are several ways to obtain this: LIAISON_MAIL, LIAISON_ELEM, CONTACTS, etc etc. You can have a single mesh with several bodies (3d-groups) too, as in my example of the press. Well, Code_Aster does not make difference in the two cases: you still need to connect each 3d-group to the others with the same methods of the two meshes, otherwise each group (orr each mesh) will float in the air.

 

More precisely: I guess that Code_Aster allways treat just ONE mesh, that can contain one or more 3d-group (if there is just one group, the 3d-group is implicit and don't need to be declared in the comm file). By consequence, If you give two meshes to Code_aster, the very first operation will be to ASSEMBLE the two meshes, in order to create a new unique one. You can avoid this step in the code_aster command file by creating a meshes compund in the mesh module of Salome.

 

 

Previously npmc wrote:

Hello,

I'm a newcomer here and I've been using Salome fora couple weeks (noobie phase).

I've got these "little" doubts that experienced people can quickly dissolve:

- Is there a Mesh algorithm more used/recommended to complex 3D shape structures?

      I've been using 3D Tetrahedron (Netgen) and NetGen 1D-2D because meshing with Hexaedron's and 3D extrusion doesn't seem very adequate/easy.

 

 

- I've been trying the LIAISON_MAIL "command". Is it recommended to be used when we want to "mate" different meshes (like Mesh_1 and Mesh_2), or it can also be used like in the Press example (by  cacciatorino) were there is only one Mesh? 

     Is there another way to assign the connections between parts in the Salome in order to the code-aster run it? (making Fuse between the parts leads to not accurate physics i guess.)

 

Best regard's.

 

 

Re: 2 quick doubts

Posted by Saint Michael at November 07. 2012

- Is there a Mesh algorithm more used/recommended to complex 3D shape structures?

NETGEN 1D-2D-3D is the best. Most of the rest algos are for particular cases.

St.Michael

Re: 2 quick doubts

Posted by npmc at November 07. 2012

Obrigado both of you, quick indeed.

I will then practice with the two tutorials I've found with various elements (3d groups), your hydraulic press and a ring assembly (c.andersen), both seem quite detailed and i hope to understand the concepts involved.

Best regards.

 

 

 

 

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