Re: [Tochnog-users] quad8 elements

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On 10/12/2013 01:49 AM, tochnog-users@... wrote:
> Hi Florenzo,
>
> I tried to use element index -quad8, but the program erred with 'I do
> not know : -quad8'. How to write the input file?
>
> Ning
You can easily see which elements are supported by looking into the 
database.cc file. I don't see quad8.
quad4, quad9, quad16 are available. The manual shows the node order for 
quad9. Quad16 should be similar.
I dont think free Tochnog allows collapsing 9 noded quad into 8. If an 
element doesn't show up in the test folder, then most likely it is not 
supported.

Osman

Ning, my apologies for giving you the incorrect information regarding the use of quad8 elements. As Osman correctly pointed out, Tochnog allows the use of quad4, quad9 and quad16. I misunderstood your question. Technically speaking quad 9 elements are in may ways better than quad8 elements. 

In many circumstances when the geometry gets complicated, I have found it better to use a preprocessor to prepare the mesh for tochnog. GiD is the recommended application, but Gmsh is another good source and there is a translator to convert a Gmsh mesh into a Tochnog input file.

Good Luck
Fernando Lorenzo
fel...@at...