Learning Forum

[LaraDlg]

Hi,

I have two shells (with constant thickness defined in ansys) , one of the shell is around the first one but they are 1mm apart at the beginning.

The inner shell has an opening with springs to deform it (the location of this opening would be changed in the DoE) and the aim of the simulation is to assess how the inner shell deforms with the restriction of the outer and softer shell. Imagine a skull expanding under the scalp.

So right now, the software makes me select every faces of each shells manually because they are not in contact yet. I have selected Frictional contact and because the shells have manually defined thicknesses, only the top and bottom faces are selected.

However, when I try to run a DoE, the software looses the manually defined contact because the opening in the shell changes and therefore the faces selected change as well.

I tried to define each shell as a named selection but the contact tool won't let me select them.

Does anyone know what I'm doing wrong or if there is a solution for this problem at all?

Thank you!

[Ashish Khemka]

Based on the maximum possible gap between the two bodies define a slightly larger pinball radius than the gap and see if that helps. Also, please see if you have the Large Deflections turned on.
Regards Ashish Khemka

[peteroznewman]

What is the geometry editor that is changing the location of the hole? Is it SpaceClaim or DesignModeler or some other CAD program?
I recommend DesignModeler for DOEs that include geometry parameters.

[LaraDlg]

the parameters are selected in DesignModeler but they are created in the geometry in Solidworks because I work with NURBBS files

[peteroznewman]

Did you bring the geometry from Solidworks into DM as a Parasolid file?
Then in DM you created parameters to move the hole? What DM feature is used to move the hole?

[LaraDlg]

Thanks for your suggestion, I've tried it but unfortunately it's still not working, the warnings ask for user input

[LaraDlg]

I used the existing link between Solidworks and Ansys: the parameters and the cuts are made in Solidworks (defined as "DS_example") and then the shells are imported as "geometry" and the parameters that I want to use later are selected in DM

[peteroznewman]

If you are using the Solidwork-Ansys Geometry Interface correctly, there is no need to use DM. The parameters should be defined in Solidworks and show up in Mechanical as CAD parameters with a DS_ prefix. Please insert some image in your reply to show exactly what you did in Solidwork and Mechanical.

[LaraDlg]

Here is the solidworks picture with the parameter definition and then the selection in DM. I've performed some DoE for this study before and it worked well but it's the first time I try to include manually defined contact. The outer shell is imported as a geometry from solidworks as well but without any parameter and it seems like this shell is the problem because it disappears (the BC for this second shell are lost). Maybe I should try to import them together from solidworks but they both have different material properties and thicknesses.

[Erik Kostson]

See if this post helps for the issue of getting in both solid and shell parts from a cad import.
Erik

[LaraDlg]

Erik
Thank you for sharing this! Do you think this could be the origin of the contact problem?

[Erik Kostson]

Hi

Not sure I am afraid - but something perhaps worth testing especially if you have surfaces/shells imported.

let us know how it goes

Erik

[LaraDlg]

I tried to assemble both shells in Solidworks to import them in one go instead of creating 2 geometries and two mechanical models but even after modifying the properties like in the post you sent, the parameters don't appear anywhere (not even in DM where they use to be). I'm guessing the issue comes from both surfaces being imported together (the import check sign appears in yellow instead of green in DM)

Lara

[LaraDlg]

it looks like at least some of the target faces are kept after changing the location of the cuts but the entire contact (and BC) from the outer shell is lost