Foam structure

Hi Everyone,

I am new to Grasshopper and Rhino.

I am facing difficulties in modeling attached closed cell foam structure. Also i'm not able to import the model to commercial (like abaqus/solid works/CATIA) to complete FE analysis.

It would be grateful if someone help me to model the attached foam structure.

Thanks in advance.

Regards

Vignesh

Attachments:

foam structure.jpg, 186 KB

Replies to This Discussion

Permalink Reply by Laurent DELRIEU on June 11, 2016 at 10:04am

Hello

3 posts for the same question, you are joking !!!! One is enough, discussion was a good place, samples & examples you are kidding and Errors and bugs (it is for real GH bug)... Could you please read this :

http://www.grasshopper3d.com/forum/topics/how-to-get-help-when-you-...

...

Permalink Reply by vignesh on June 11, 2016 at 11:23am

Hello

I am not joking. Just i am new to the forum.

Nevertheless sorry for three posts. I shall remove it now.

Permalink Reply by David Rutten on June 11, 2016 at 1:51pm

Isn't it just a 3D voronoi from a bunch of random but well-distributed points?

Permalink Reply by vignesh on June 16, 2016 at 9:26am

I tried 3d voronoi from random points inside box and then baked. I need to join all poly surfaces into single surface.

Please find attached model, in which i have to combine all the surfaces into single surface.

Permalink Reply by peter fotiadis on June 16, 2016 at 10:06am

combine all the surfaces into single surface.

You mean join Breps?? But that yields a polysurface (the equivalent of a so called "smart" surface in CAD apps using the ParaSolids engine) that is NOT a "single" surface: it's just a "kind" of List (kinda) of Breps.

If your goal is talking to CATIA effortlessly I could prepare a small demo on that matter (using STEP 214).

BTW: As David said ... this is a 3D Voronoi minus some BrepFaces according to some kind of logic (prox at boundary ?? or what else?).

Permalink Reply by Laurent DELRIEU on June 16, 2016 at 12:43pm

Hello

here a solution to suppress borders and duplicate faces and transform that in a list of single faces. I transform that also in a mesh. At the end I think you want a single solid in order to apply FEM (mesh triangles or quad). I try to join but it is not possible, Rhino doesnt like to make impossible thinks. If wall became thick Rhino will surely handle that.

Attachments:

foam_voronoi.gh, 10 KB

Permalink Reply by vignesh on June 17, 2016 at 12:31pm

Hello Laurent

1) First Thanks a lot for help.

2) As you said i want a single solid in order to apply FEM. Is it possible to give thickness to cell walls and then join using Rhino?

3) I tried exporting the model in STP format.But i'm getting error message as "polygon meshes were not exported"

I would highly value your advise you give me.

Thanks in advance.

Permalink Reply by Laurent DELRIEU on June 17, 2016 at 1:10pm

Before going to far, I understand that you used CATIA surface design so you get a topological error which seems logic, it is the same for a mesh because there is no inside or outside. So your FEM will it be with triangles/quad (surface) or shell/tetrahedral (volume) ?

With "tet" one solution will be to smooth each voronoi and do something like in this paper :

Build-to-Last: Strength to Weight 3D Printed Objects

https://www.cs.bgu.ac.il/~asharf/3dprintsig.pdf

Have you some documentation in order to have some clues where we can help ?

Permalink Reply by Laurent DELRIEU on June 17, 2016 at 1:16pm

here is a STEP model, I didn't bake the mesh but where there is the arrow

It seems that Abaqus can "join" "combine into single part"

http://www.intrinsys.com/blog/2016/importing-parts-into-abaqus-cae

Attachments:

foam.stp, 1.2 MB

Permalink Reply by vignesh on June 17, 2016 at 1:25pm

I was intended to use 4 node Shell element (S4R in ABAQUS Library) for each foam cell wall.

If all cell walls are combined to single surface (one part), i can import it into ABAQUS.

I have tried using CATIA, only to combine surfaces. But it failed.

Permalink Reply by vignesh on June 17, 2016 at 12:43pm

Hello Peter,

Thanks a lot for help.

I have created a 3D Voronoi model (having 3129 faces) with faces removed. Then exported to CATIA in order to combine all 3129 faces to single surface.

I have used 'JOIN' option from SURFACE DESIGN workbench in CATIA. But i got topological error.

I am trying to Join all 3129 surfaces into single surface.So that i can export to ABAQUS in order to do FEM Analysis.Kindly advise.

I could send Voronoi Model and CATIA model to you if needed.

Thanks.

Permalink Reply by Laurent DELRIEU on June 17, 2016 at 1:35pm

One surface seems to be difficult due to topology concern. But it seems that it is possible when importing STEP in ABAQUS to "combine into single part", so it could be your answer ?

http://www.intrinsys.com/blog/2016/importing-parts-into-abaqus-cae