Solid model with shell skin

[Breezer]

Hi all,

Can someone explain to me why ones would build a finite element solid model with a shell skin? Is it for more accurate answers on the surface? How does one determine the shell thickness to get the most accurate answer bearing in mind not to add too much material or additional stiffness to the model?

Thank you.
A

 

[mloew]

This topic has been covered before in the thread Coating Solid Mesh with plates for Stress Recovery. (thread727-46439)

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Breezer]

I obviously didn't search successfully.

Thanks, Matt

 

[mloew]

AnnHer,

Not a problem. The search function seems a bit dodgy at times. I hope you find what you are looking for. Welcome to the fora.


Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[brc01]

Gary Mostyn in the same thread says he uses Tet elements for fatigue analysis and coated with triangular elements.Are Tets appropriate for problems involving strain gradients as in fatigue problems?Moreover traingular elements are also overly stiff.Aren't they? Any comments?


brc01

 

[mloew]

Higher order tetrahedral (10-node) and triangular (6-node) elements avoid the problem of constant strain in the element formulation. This topic has been discussed before, but I do not know in what threads. Try the search facility and Google. Perhaps someone will create a FAQ on this topic.

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[brc01]

Loew,
You are right,
but tets and triangular shells are still not as good as hexahedrons and general shells respectively and I am still sceptical of using them wherever high strain gradients are involved.

Perhaps one can use hexahedrons in critical regions coupled to tets in rest of the model.In ANSYS one can do that.


Regards
brc01