[Gmsh] Stress on Gauss Points

[Jeremy Theler]

On Thu, 2019-02-14 at 10:56 -0500, Max Orok wrote:
> Jeremy, 
> 
> You're right, there isn't any explicit averaging going on, it just
> goes through all the nodes and assigns values based on their number. 
> After assigning I trusted Gmsh to display them nicely :):)

ok, I now finally understood your script... I made up a simplified 2d
version, see attached


> This does mean that node data values are set multiple times -> to the
> same value (magnitude at least).

yes, I can see... nodes 2 and 3 get scalars 5 and 8, whilst I would
expect and averaging between 2 and 5 in node 2 and 8 and 3 in node 3 :-
/

> A lot of the data on each row is duplicated elsewhere in the file, my
> idea was that if the elements were ordered correctly, the 
> repeated overwrite wouldn't matter as long as the overwrite contained
> the same number. 

this is the point, the data is not repeated! stresses or whatever
evaluated at the gauss points in different elements will surely contain
different values, even if they are near the same node... am I clear?

I am interesting in seeing how to average these values to assign them
to the shared node...
plain average? weighted average? how? using the element's volume? the
element's quality? etc


regards
--
jeremy theler
www.seamplex.com
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$MeshFormat
2.2 0 8
$EndMeshFormat
$Nodes
6
1 0 0 0
2 1 0 0
3 1 1 0
4 0 1 0
5 2 0 0
6 2 1 0
$EndNodes
$Elements
2
1 3 2 1 1 1 2 3 4
2 3 2 1 1 2 5 6 3 
$EndElements
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$MeshFormat
4 0 8
$EndMeshFormat
$Entities
0 0 1 0
1 0 0 0 2 1 0 1 1 0 
$EndEntities
$Nodes
1 6
1 2 0 6
1 0 0 0
2 1 0 0
3 1 1 0
4 0 1 0
5 2 0 0
6 2 1 0
$EndNodes
$Elements
1 2
1 2 3 2
1 1 2 3 4 
2 2 5 6 3 
$EndElements
$InterpolationScheme
"INTERPOLATION_SCHEME"
1
4
2
4 4
0.25 -0.25 0.25 -0.25 
0.25 0.25 -0.25 -0.25 
0.25 0.25 0.25 0.25 
0.25 -0.25 -0.25 0.25 
4 2
0 0 
1 0 
1 1 
0 1 
$EndInterpolationScheme
$NodeData
1
"scalars"
1
0
3
0
1
6
1 1
2 5
3 8
4 4
5 6
6 7
$EndNodeData