2D axisymmetric

About the development of the FEM module/workbench.

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schupin
Posts: 304
Joined: Sun Jan 21, 2018 1:43 pm

2D axisymmetric

Postby schupin » Thu Oct 10, 2019 11:55 am

Hi,

I'll like to know if there is a way to do a 2D-axisymmetric analysis with FreeCAD and Calculix through the FEM workbench ?
fandaL
Posts: 344
Joined: Thu Jul 24, 2014 8:29 am

Re: 2D axisymmetric

Postby fandaL » Thu Oct 10, 2019 9:16 pm

CalculiX can do it so after modifying inp file from FreeCAD, you could get it working. Maybe this can help for the beginning:

Create a 2D model in xy plane where y is the axis of symmetry, as if you are making shell analysis, but do not constraint nodal rotations.

Write inp file, modify element type, e.g.

Code: Select all

*Element, TYPE=S6, ELSET=Efaces
** change to axisymmetric type:
*Element, TYPE=CAX6, ELSET=Efaces
and change SHELL SECTION to SOLID SECTION, e.g.

Code: Select all

*SHELL SECTION, ELSET=SolidMaterialElementGeometry2D, MATERIAL=SolidMaterial
20
** change to:
*SOLID SECTION, ELSET=SolidMaterialElementGeometry2D, MATERIAL=SolidMaterial
According to the manual https://www.feacluster.com/CalculiX/ccx ... ode54.html , loads in the plane should have size as if they are acting on the whole circumference.
Jckcdt
Posts: 10
Joined: Tue Oct 22, 2019 9:02 am

Re: 2D axisymmetric

Postby Jckcdt » Fri Nov 29, 2019 2:55 pm

Hello,

Any chances to get it work on a 3D analysis on a complex geometry ?

I'm trying to modelize the stresses in the welds between the hub and the flanges of a gear wheel of about 4 meters diameter, so the number of nodes if more than 5 millions, and Calculix goes outrange.

As it is a axisymmetric shape, the good solution would be the cut it in 8 and to apply symmetry on the cutted faces. But I don't find any example of such apllication on freecad FEM. Do you know if there is a trick, or if there are any ongoing developments ?

Thanks,

Jonathan
Jee-Bee
Posts: 1969
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: 2D axisymmetric

Postby Jee-Bee » Fri Nov 29, 2019 3:26 pm

you need this function
https://www.feacluster.com/CalculiX/ccx ... de231.html

i think you can create 1/8 of the model.
create some constraints so you can find it back in the files.
and modifie it as in the example