Meshing of shell structure

[s103531]

Hi I am having some challenges when meshing a shell structure, I have both modelled it directly in Robot and also imported a .SAT model. The first problem is: The mesh does not triangulate, when I choose triangular elements. I have tried changing the settings to 'force' triangular elements without luck. I can work around this by setting the 'Triangulization near edges' to 4, but it seems highly illogical to do it this way. The second problem: When I reach a certain mesh size (approx. 0.75m in my case), the main parts of the mesh are no longer refined, and only the amount of elements along the edges increase. I can get more element by splitting each element - but that only gives me more points, not a better shape approximation. I hope it makes sense. Best regards Tina

[s103531]

I'll just attach one of my files - however it also happens when I mesh a continuous spherical cap.

[s103531]

Maybe this time, the file is actually attached..

[Artur.Kosakowski]

Try one of these services:

http://forums.autodesk.com/t5/robot-structural-analysis/sending-bigger-files/td-p/3795062

[s103531]

Thanks Artur. Hopefully fourth time is the charm. Here is the link for my robot file: https://fil.email/1BwfuA

[Artur.Kosakowski]

As your structure has been defined as ACIS object which is not recommended for shells the meshing algorithm is different than the options available for "standard" panels and the only solution is as the one you already tried however I can't see any issue with having smaller elements.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[s103531]

Can I define the shell differently, either by modelling it in Robot or importing it. The file you see, has a panel modelled directly in Robot.

I am also able to define a smaller mesh size, but the main part  of the elements are still 0.75m, and I guess the element edge length along the edge curves matches the size that I have prescribed for the elements. This means that the elements along the edge are very oblong.

[s103531]

I'm just gonna try again, in hopes that you see my reply. Can I define the shell differently, either by modelling it in Robot or importing it. The file you see, has a panel modelled directly in Robot, so it seems odd that the shell elements do not work properly - maybe the problem occurs, when I perform boolean operations to create the holes. I am also able to define a smaller mesh size, but the main part of the elements are still 0.75m, and I guess the element edge length along the edge curves matches the size that I have prescribed for the elements. This means that the elements along the edge are very oblong.

[Rafacascudo]

Why Bolean operations??

Just create a regular contour and set it as "opening"

[s103531]

Because I figured that I wouldn't be able to draw a contour on a curved surface. This way, I have cut the holes with cylinders.

[Artur.Kosakowski]

You may want to have a look at this topic:

http://forums.autodesk.com/t5/robot-structural-analysis/import-autocad-meshes-in-arsa/m-p/4746821

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.