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#1 2009-10-29 22:46:44

mtg450
Member
Registered: 2008-06-17
Posts: 7

question regarding forces on a face

Hello,

I want to make sure if i understood the structure correctly.

when i use FORCE_ FACE on a surface the applied value has a f.e. a structure N/mm2 like the PRES operand, is that correct?

so if I want to apply a force distributed to a surface i have to divide it by the size of the surface?

Is there a more (convenient) way to apply forces on a surface? I would need it because the surface i have is not so easy to calculate

Andre

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#2 2009-10-30 09:42:55

jo
Member
From: Ingenieurbüro für Mechanik, DE
Registered: 2008-01-29
Posts: 146
Website

Re: question regarding forces on a face

"when i use FORCE_ FACE on a surface the applied value has a f.e. a structure N/mm2 like the PRES operand, is that correct?"

Yes, You understood correctly. The naming of the Code-Aster load types make it easy to understand the dimension:  FORCE_ FACE means force per surface (N/m2). FORCE_ NODAL means force per node (N onto each node), FORCE_ ARETE means force per edge length (N/m).

To avoid misunderstanding: of course is dimension-free. It is up to You to interpret millimeter instead of m, kg instead of ton etc.

FORCE_ FACE and PRES have the same dimension. The difference is that for  FORCE_ FACE You have to input the direction of the load (spatial components) while using PRES the direction is always the normal onto the elm plane.

"so if I want to apply a force distributed to a surface i have to divide it by the size of the surface?"

Yes

"Is there a more (convenient) way to apply forces on a surface?"

No

"I would need it because the surface i have is not so easy to calculate"

It is easy to calculate inserting just these lines in Your command file:

tab_post=POST_ELEM(MASS_INER=_F(TOUT='OUI',),
MODELE=mode,
CHAM_MATER=mat,
CARA_ELEM=cara,
TITRE='tit_of_post_elem',);
IMPR_TABLE(TABLE=tab_post,);

Johannes Ackva
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Ingenieurbüro für Mechanik
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